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1
Zhang, Kaitian, Jianhua Liu e Heng Cui. "Investigation on the Slag-Steel Reaction of Mold Fluxes Used for Casting Al-TRIP Steel". Metals 9, n. 4 (1 aprile 2019): 398. http://dx.doi.org/10.3390/met9040398.
Testo completoAbstract (sommario):
The reaction between [Al] in molten steel and (SiO2) in the liquid slag layer was one of the restrictive factors in the quality control for high Al-TRIP steel continuous casting. In this work, the composition and property variations of two slags during a slag-steel reaction were analyzed. Accordingly, the crystalline morphologies of slag were discussed and the solid layer lubrication performance was evaluated by Jackson α factors. In addition, a simple kinetics equilibrium model was established to analyze the factors which affected SiO2 consumption. The results reflected that slag-steel reacted rapidly in the first 20 minutes, resulting in the variation of viscosity and the melting temperature of slags. The slag-steel reaction also affected the crystal morphology significantly. Slag was precipitated as crystals with a higher melting temperature, a higher Jackson α factor, and a rougher boundary with the consumption of SiO2 and the generation of Al2O3. In other words, although generated Al2O3 acted as a network modifier to decrease the viscosity of the liquid slag layer adjacent slab shell, the consumption of SiO2 led to the deterioration of the lubrication performance in the solid slag layer adjacent copper, which was detrimental to the quality control for high Al-TRIP steel. Finally, a kinetics equilibrium model indicated that it is possible to reduce a slag-steel reaction by adjusting factors, such as the diffusion coefficient k, cSiO2, ρf and Lf, during the actual continuous casting process.
2
Li, Qi Nan, Guo Jun Ma, Xiang Zhang e Xun Cai. "Characteristics of Metallurgical Waste Slag and its Heating Behavior in a Microwave Field". Key Engineering Materials 680 (febbraio 2016): 574–79. http://dx.doi.org/10.4028/www.scientific.net/kem.680.574.
Testo completoAbstract (sommario):
Four kinds of typical metallurgical waste slags were characterized with their chemical composition, crystalline phases, microstructure and thermal behavior. The heating behavior of these slags in a microwave field were also examined. The results show that there is a high content of CaO in these waste slags. When the metallurgical waste slags were heated from room temperature to 1300°C, the weight loss of Blast Furnace (BF) slag and ladle furnace (LF) refining slag are only 2.25% and 0.9%, respectively, while the weight loss of Basic Oxygen Furnace (BOF) slag and electric arc furnace (EAF) slag are more than 5%. These metallurgical waste slags have a good absorption capacity for the microwave irradiation, the absorption capacity of microwave decreases in the order of converter slag > EAF carbon steel slag > baste furnace slag. In addition, the temperature-rising rates of the metallurgical waste slags increase with the microwave power and the quality or the particle sizes of slags. Furthermore, the crystalline phases of treated slag with microwave are similar with that of the untreated metallurgical slag. A number of internal cracks in particles of metallurgical slag can be found or extended after microwave treatment.
3
Gupta, Avishek Kumar, Matti Aula, Jouni Pihlasalo, Pasi Mäkelä, Marko Huttula e Timo Fabritius. "Preparation of Synthetic Titania Slag Relevant to the Industrial Smelting Process Using an Induction Furnace". Applied Sciences 11, n. 3 (27 gennaio 2021): 1153. http://dx.doi.org/10.3390/app11031153.
Testo completoAbstract (sommario):
A high titania slag that is used as a feedstock for TiO2 manufacturing is obtained by ilmenite smelting (FeO.TiO2). The composition of the slag obtained by smelting is dependent on the composition of the mineral used for slag preparation, i.e., ilmenite in our study. At the laboratory scale, ilmenite slags are mostly obtained by using ilmenite as the raw material. An easy and simple way would be to prepare the synthetic slag using the individual components and heating them to high temperature in a furnace. The titania slag has a high oxidizing nature and requires an inert atmosphere to prevent oxidation of the slag as well as the molybdenum crucible. This paper describes the preparation of synthetic ilmenite slag using an induction furnace and the study of the composition and the phases formed in the slag. X-ray powder diffraction (XRD), scanning electron microscopy (SEM), and inductively coupled plasma-optical emission spectroscopy (ICP-OES) were used as analytical techniques for studying the slag. A comparison between obtained synthetic slag and industrial ilmenite slag was performed to test the possibility of preparing slags in the laboratory as per the required composition. The slags show similar phase formation as obtained in industrial ilmenite slags, which means that the synthetic slags are identical to the industrial slags.
4
Zhao, Qiang, Lang Pang e Dengquan Wang. "Adverse Effects of Using Metallurgical Slags as Supplementary Cementitious Materials and Aggregate: A Review". Materials 15, n. 11 (26 maggio 2022): 3803. http://dx.doi.org/10.3390/ma15113803.
Testo completoAbstract (sommario):
This paper discusses a sustainable way to prepare construction materials from metallurgical slags. Steel slag, copper slag, lead-zinc slag, and electric furnace ferronickel slag are the most common metallurgical slags that could be used as supplementary cementitious materials (SCMs) and aggregates. However, they have some adverse effects that could significantly limit their applications when used in cement-based materials. The setting time is significantly delayed when steel slag is utilized as an SCM. With the addition of 30% steel slag, the initial setting time and final setting time are delayed by approximately 60% and 40%, respectively. Because the specific gravity of metallurgical slags is 10–40% higher than that of natural aggregates, metallurgical slags tend to promote segregation when utilized as aggregates. Furthermore, some metallurgical slags deteriorate the microstructure of hardened pastes, resulting in higher porosity, lower mechanical properties, and decreased durability. In terms of safety, there are issues with the soundness of steel slag, the alkali-silica reaction involving cement and electric furnace ferronickel slag, and the environmental safety concerns, due to the leaching of heavy metals from copper slag and lead-zinc slag.
5
Long, Xiao, Wenbo Luo, Guohong Lu, Falou Chen, Xiaoning Zheng, Xingfan Zhao e Shaolei Long. "Iron Removal from Metallurgical Grade Silicon Melts Using Synthetic Slags and Oxygen Injection". Materials 15, n. 17 (1 settembre 2022): 6042. http://dx.doi.org/10.3390/ma15176042.
Testo completoAbstract (sommario):
Novel SiO2-CaO-CaF2-R2O-MgO based synthetic slags (R2O represents alkali metal oxides) with varied binary basicity values were used with oxygen injection to refine silicon melts and remove Fe from metallurgical-grade silicon. Silicon samples and slags at the silicon-slag interfaces were obtained during refinement. The compositions of the silicon samples were analyzed, and the quenched slag samples and mild cooling slags from the final crucible were inspected using scanning electron microscopy and energy dispersive X-ray spectroscopy. After 15 min of refinement, the Fe removal rate ranged from 52.3 to 60.1 wt%. During the refining process, the Fe-concentrated phase formed within the silicon droplets and was then transferred to the silicon-slag interfaces and wetted with slags. The Fe-concentrated phase at the silicon-slag interface can dissolve directly in the slags. It can also be transferred into the slag phase in the form of droplets, which can be affected by the binary basicity of the slags. Ti removal demonstrated a similar mechanism. Fe-bearing crystals were not detected in the quenched slag samples obtained during refinement, while complex Fe-bearing phases were detected in the final slag. This study demonstrates Fe removal from metallurgical-grade Si using slag refining methods and reveals the removal mechanism during the refinement.
6
Liu, Xingbei, Chao Zhang, Huanan Yu, Guoping Qian, Xiaoguang Zheng, Hongyu Zhou, Lizhang Huang, Feng Zhang e Yixiong Zhong. "Research on the Properties of Steel Slag with Different Preparation Processes". Materials 17, n. 7 (28 marzo 2024): 1555. http://dx.doi.org/10.3390/ma17071555.
Testo completoAbstract (sommario):
To promote the resource utilization of steel slag and improve the production process of steel slag in steelmaking plants, this research studied the characteristics of three different processed steel slags from four steelmaking plants. The physical and mechanical characteristics and volume stability of steel slags were analyzed through density, water absorption, and expansion tests. The main mineral phases, morphological characteristics, and thermal stability of the original steel slag and the steel slag after the expansion test are analyzed with X-ray diffractometer (XRD), scanning electron microscope (SEM), and thermogravimetric analysis (TG) tests. The results show that the composition of steel slag produced by different processes is similar. The main active substances of other processed steel slags are dicalcium silicate (C2S), tricalcium silicate (C3S), CaO, and MgO. After the expansion test, the main chemical products of steel slag are CaCO3, MgCO3, and calcium silicate hydrate (C-S-H). Noticeable mineral crystals appeared on the surface of the steel slag after the expansion test, presenting tetrahedral or cigar-like protrusions. The drum slag had the highest density and water stability. The drum slag had the lowest porosity and the densest microstructure surface, compared with steel slags that other methods produce. The thermal stability of steel slag treated by the hot splashing method was relatively higher than that of steel slag treated by the other two methods.
7
Potysz, Anna, Bartosz Mikoda e Michał Napieraj. "(Bio)dissolution of Glassy and Diopside-Bearing Metallurgical Slags: Experimental and Economic Aspects". Minerals 11, n. 3 (3 marzo 2021): 262. http://dx.doi.org/10.3390/min11030262.
Testo completoAbstract (sommario):
Dissolution of diopside-bearing slag and its amorphous counterpart was investigated to decipher recovery potential of these slags. The contribution of direct slag phase dissolution was investigated using a biotic solution with Acidithiobacillus thiooxidans versus sterile growth medium, whereas citric acid was applied to demonstrate slags dissolution in organic medium. Potential metal donor slag phases and easily released elements were identified by comparing theoretical and experimental dissolution ratios. It was shown that K and Na were the most mobile elements leaching from glassy and diopside slag (up to 99%). Recovery targeted metals were released in the quantities of 56% (Cu)–96% (Zn) from glassy slag and 27% (Cu)–98% (Zn) from diopside slag. Results demonstrated that studied slags are good candidates for Zn recovery during short-term treatment, whereas extension of time would be required for efficient Cu extraction. Abiotic growth medium had little effect on metal leaching (up to 53% versus only 3% for the glassy and diopside slags, respectively). Glassy slag revealed greater susceptibility to dissolution as compared to diopside slag. Further studies improving recovery conditions are expected to improve environmental soundness of proposed treatments and to generate residues depleted in toxic elements. This study highlights the importance of evaluation of individual slags in terms of metal and major elements leachability.
8
Zhou, Sheng Bo, Ai Qin Shen e Geng Fei Li. "Interaction between Slag and Clinker during Cement Hydration Process". Advanced Materials Research 857 (dicembre 2013): 70–74. http://dx.doi.org/10.4028/www.scientific.net/amr.857.70.
Testo completoAbstract (sommario):
In order to investigate the activity of different original slags and the coupled relation between the slag and the clinker, the simplified slag cement system was designed in the experiment, in which clinker was replaced by lime.The reactional degree of slag in cement was determined through using chemical combined water content method, and the hydration processs were determined through using DSC-TGA. The results showed that for the different original slags, the destruction and rebuilding process of their microstructure were important to distinguish the activity of slags. And the process of slag hydration mainly experienced two stages, including microstructure destruction at early ages and microstucture rebuilding at later ages. And the variation of Calcium hydroxide content in cement indicated the interaction between the slag and clinker, and slag may improve the clinker hydration velocity.
9
Pfeiffer, Andreas, Kathrin Thiele, Gerald Wimmer e Johannes Schenk. "Laboratory Scale Evaluation of the Slag Foaming Behavior". IOP Conference Series: Materials Science and Engineering 1309, n. 1 (1 maggio 2024): 012007. http://dx.doi.org/10.1088/1757-899x/1309/1/012007.
Testo completoAbstract (sommario):
Abstract Due to the ambitious climate targets of the European Union, one can expect that the electric arc furnace (EAF) will gain greater importance in the future of steelmaking. Since slag foaming is a decisive factor in an efficient process, understanding this phenomenon is essential when applying hydrogen-based direct reduced iron (DRI). Therefore, a method was developed to check different slag compositions concerning their foaming behavior. Slag samples are melted, and a carbon carrier is added. After a selected reaction time, the crucible is quenched in liquid nitrogen, superficially freezing the state while foaming. Afterward, it is halved, providing metallographic examination and height measurement possibilities. Three slags were tested, MgO-saturated EAF slag, MgO-unsaturated EAF slag, and electrical Smelter-like slag. Digital and scanning electron microscopy with energy dispersive x-ray spectroscopy are used to compare the slags and evaluate the method. The Smelter slag shows no foamability, unaffected by the FeO content. Contrary, good foamability can be observed for EAF slags.
10
Jiang, Dongbin, Xiaoxuan Peng, Ying Ren, Wen Yang e Lifeng Zhang. "Water modeling on slag entrainment in the slab continuous casting mold". Metallurgical Research & Technology 119, n. 6 (2022): 601. http://dx.doi.org/10.1051/metal/2022083.
Testo completoAbstract (sommario):
A water model is built to investigate the transport phenomena in the slab continuous casting mold. The gas flow rate, casting speed, and slab width on the slag entrainment are studied. The sliver defect in the IF steel plate is analyzed by the scanning electron microscope. The slag entrainment is recorded by the high-speed camera and the velocity is measured by the PIV. The results show that sliver defects contain Al, Ca, Si, Mg, Na, and O, which are mainly derived from the mold slag entrainment. With the casting speed increase, the fluid velocity from the submerged entry nozzle rises clearly and the slag droplets detach from slag layer. As the gas flow rate increases, the liquid moves upward with bubble floating and attacks the slag-steel interface. It is suggested the gas flow rate should be less than 3.3 NL/min for the slab width of 1300 mm and the casting speed of 1.2 m/min. With the slab width increasing from 1300 mm to 1700 mm, no slag entrainment zone is reduced. The gas flow rate should be below 2.2 NL/min with the casting speed increasing to 1.4 m/min, both for the slab width of 1300 mm and 1700 mm.
11
Eric, R. H. "Chromous capacities of ferrochromium and matte smelting slags". Archives of Materials Science and Engineering 2, n. 93 (1 ottobre 2018): 49–58. http://dx.doi.org/10.5604/01.3001.0012.7354.
Testo completoAbstract (sommario):
Purpose: of this paper is to extend the slag capacity concept to sparingly soluble cationic species encountered for example in matte smelting and ferrochromium processing in terms of chromous capacities. Design/methodology/approach: In this context in order to develop the chromous capacity the experimental data on slag-metal equilibrium for ferrochromium smelting and on chromium distribution between slag and matte phases encountered in sulphide smelting of PGM (Platinum Group Metals) and chromium containing copper nickel concentrates were used. Findings: The calculated chromous capacities were in the 10-8 range for ferrochrome smelting slags and 10-4 range for matte smelting slags. These values indicate the very low and moderate chromous ion dissolving ability of ferrochromium smelting slags and matte smelting slags respectively. Research limitations/implications: Due to highly reducing conditions in ferrochromium smelting and the imposed low oxygen partial pressures in sulphide smelting of chromium and PGM containing concentrates chromium in the slag was assumed to be in its divalent state. The slag-metal/matte reaction for dissolution of chromium into the slag as a cation under reducing conditions -in contrast to reactions for dissolution of species such as sulphur and phosphorus into the slag as anions under oxidizing conditions – required the release of electrons. Thus to maintain charge neutrality the dissolution of chromium from the metal or the matte phases into the slag as Cr2+ ions was accompanied by consumption of these electrons by reduction of Fe2+ ions in the slag into metallic Fe which dissolved in the metal/ matte phase. This was supported by the experimental equilibrium data. Hence the slagmetal/ matte reaction defining the chromous capacity involved both O2- and Fe2+ ions of the slag phase. Moreover for matte smelting the thermodynamic activities of species in the matte phase were assumed to conform to ideal associated solution model due to lack of data. For future work it is advisable to determine such activities. Practical implications: The calculated chromous capacities were in the 10-8 range for ferrochrome smelting slags and 10-4 range for matte smelting slags. The results clearly indicate that in matte smelting lower basicity slags would be preferable to render chromium more soluble in the slag in contrast to ferrochromium smelting where higher basicity slags would be suitable to minimize chromium losses to the slag. Originality/value: This research and hence the paper is probably the first on dissolution of chromium as chromous ion in slags, thus it is novel and original.
12
Dai, Yuxiang, Jing Li, Wei Yan e Shenyang Song. "Effect of slag-remaining operation on dephosphorization based on single-slag converter steelmaking technology". Metallurgical Research & Technology 116, n. 5 (2019): 504. http://dx.doi.org/10.1051/metal/2019032.
Testo completoAbstract (sommario):
During converter steelmaking process, large amounts of slags are generated which take away heat and iron resources from molten bath. The slag-remaining operation is a kind of hot slag recycling. It is that all or most of the slags are left in the converter for next heat during continuous production of several successive heats. The basicity of the remaining slag is about 3, and the content of (FeO) is about 20%.When slag-remaining operation is adopted, it increases the slagging speed in the early stage. Influence of slag-remaining process on the dephosphorization during converter steelmaking was studied through industrial practice and theoretical calculation. The results show that the slag-remaining operation can realize low cost and high efficiency for converter steelmaking. It can reduce the consumption of lime and achieve better dephosphorization effect. But phosphorus content in slag increases gradually with the increase of slag remaining times and the dephosphorization capacity of slag is reduced, which result in the poor dephosphorization of steel. Therefore, the times of slag-remaining should be less than 5 to ensure the dephosphorization of steel.
13
Wang, Hui, Su Ping Cui e Ya Li Wang. "Influence of Cooling Ways on the Structure and Hydraulic Activity of Blast Furnace Slag". Key Engineering Materials 633 (novembre 2014): 234–39. http://dx.doi.org/10.4028/www.scientific.net/kem.633.234.
Testo completoAbstract (sommario):
Using the industrial limestone, fly ash and pure chemical reagents as raw materials, the blast furnace slag was prepared in the simulation condition of the actual slag-making process by three different cooling ways, including air cooling, water cooling and liquid nitrogen cooling. Combined with different test methods such as XRD, SEM, IR, the influence of cooling ways on the structure and hydraulic activity of blast furnace slag was studied in the present in investigation. The relationship between glass content, compressive strength and the phase compositions of blast furnace slag has been obtained. The results showed that, the glass content of water cooling slag or liquid nitrogen cooling slag was slightly higher than that of air cooling slag, there was obviously gehlenite crystal phase in air cooling slag. The 7d and 28d compressive strength of three slags did not present positive correlation with vitreous content, the sequence of 28d compressive strength of three slags was water cooling slag > air cooling slag > liquid nitrogen cooling slag. SEM observation found that crystallization phases in water cooling slag had a small grain and uniform distribution, this kind of structure was advantageous to the latter hydration reaction and strength development of blast furnace slag.
14
Shi, Guan-yong, Ting-an Zhang, Li-ping Niu e Zhi-he Dou. "Study on physical properties of Al2O3-based slags used for the self-propagating high-temperature synthesis (SHS) – metallurgy method". High Temperature Materials and Processes 41, n. 1 (1 gennaio 2022): 424–33. http://dx.doi.org/10.1515/htmp-2022-0046.
Testo completoAbstract (sommario):
Abstract The Al2O3-based slags are playing important roles in the preparation of Cu–Cr alloy through self-propagating high-temperature synthesis (SHS) – Metallurgy method. However, the current research on Al2O3-based slag is mainly concentrated on steel metallurgical slag and electroslag remelting slag, and the research on aluminum thermal reduction slag with high content of Al2O3 is still insufficient. Therefore, systematic studies of the physical properties of slag with high aluminum content were carried out in the present work, and the influence of CaF2, CaO, MgO, SiO2, and Na3AlF6 on viscosities, liquidus temperatures, densities, and surface tensions of high Al2O3 content slags was measured and analyzed. The results indicated that CaO and CaF2 have positive effects on the physical properties of Al2O3-based slags, MgO has positive effects when its content is not over 3%, and SiO2 and Na3AlF6 have negative impacts. CaO, CaF2, and MgO (not over 3%) could be used as additives to improve the metallurgical performance of Al2O3-based slags in aluminothermic reduction–slag refining method.
15
Cao, Jianqi, Yao Li, Wanming Lin, Julong Che, Feng Zhou, Yunfang Tan, Dongliang Li, Jie Dang e Chao Chen. "Assessment of Inclusion Removal Ability in Refining Slags Containing Ce2O3". Crystals 13, n. 2 (23 gennaio 2023): 202. http://dx.doi.org/10.3390/cryst13020202.
Testo completoAbstract (sommario):
The elimination of inclusions in steelmaking processes has been widely studied. The removal of inclusions by slags containing the rare earth oxide Ce2O3 are studied using an integrated numerical model. The integrated model involves the inclusion motion model, interfacial tension calculation model, surface tension calculation model of slag, and the mass action concentration model, based on ion and molecule coexistence theory. The motion behaviors of both solid Al2O3 inclusions and 50%wtAl2O3–50%wtCaO liquid inclusions of varied sizes at CaO-Ce2O3-SiO2-Al2O3(-MgO) slag systems are evaluated. The results show that it is more difficult to remove the inclusions with smaller sizes and in slag with a higher viscosity. Liquid inclusions are more difficult to remove than solid inclusions. It is found that the CaO-Ce2O3-SiO2-Al2O3-MgO refining slag shows a better ability to remove Al2O3 inclusions than that of the CaO-SiO2-Al2O3-MgO slag. The reason for this is that the addition of the rare earth oxide Ce2O3 can decrease the viscosity of slags, as well as improving the wetting effects of slags on Al2O3 inclusions. For two slags systems, the CaO-Ce2O3-SiO2-Al2O3-MgO slag system shows a better ability to remove Al2O3 inclusions than the CaO-Ce2O3-SiO2-Al2O3 slag system. The addition of 5% to 8% Ce2O3 in a CaO-SiO2-Al2O3-MgO slag is an optimized case for industrial applications.
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Barnett, Vincent L. "Slags and Slag Heaps". Film International 20, n. 3 (1 settembre 2022): 36–43. http://dx.doi.org/10.1386/fint_00171_1.
Testo completo
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Gao, Ju, e Cheng Liang Du. "Study of Large Inclusions in Casting Slab of 45# Steel". Advanced Materials Research 634-638 (gennaio 2013): 1859–63. http://dx.doi.org/10.4028/www.scientific.net/amr.634-638.1859.
Testo completoAbstract (sommario):
According to the production process of 45#steel(120t BOF→ slag refining →CC), some system analysis are introduced to research on the type, composition and quantity of large inclusions in casting slab under slag washing process, the effect of slag washing production process on the cleanliness of casting slab is evaluated. The results of the study show that: Under slag washing process, many of large inclusions are spherical inclusions，the main type of large inclusions is CaO-SiO2-Al2O3-MnO complex inclusion andSiO2-Al2O3 inclusion; the content of large inclusions in normal slab is 5.17mg/10kg, it is lower than that under un-slag washing process; the content of large inclusions in head slab is 108.82mg/10kg, it’s 21.05 times higher than that in normal slab; the content of large inclusions in compound casting slab is 15.94mg/10kg, it’s 3.08 times higher than that in normal slab; the content of large inclusions in casting slab is slightly higher under the condition of unsteady casting; the main inclusions with a size of between 140μm and 300μm in head slab, take up 70.13%, the inclusions with a size of more than 300μm is second, take up 29.24%, and the least is inclusions with a size of between 80μm and 140μm, only take up 0.63%. The level of the molten steel fluctuated remarkably, slag entrapment and secondary oxidation is serious at the casting start and compound casting, which cause the cleanliness of casting slab decreasing. Unsteady casting has great effect on the cleanliness of casting slab.
18
Liu, Kuisheng, Zengqi Zhang e Jianwei Sun. "Advances in Understanding the Alkali-Activated Metallurgical Slag". Advances in Civil Engineering 2021 (22 maggio 2021): 1–16. http://dx.doi.org/10.1155/2021/8795588.
Testo completoAbstract (sommario):
This paper summarized and reviewed the mechanism and macro-performance of alkali-activated metallurgical slag, including steel slag, copper slag, ferronickel slag, and lead-zinc slag. Better activated method and alkali-activator are still needed to be developed to improve the performance of the metallurgical slag with low reactivity. Besides, the chemical components’ variation of these metallurgical slags from different regions will lead to unpredictable performance, which needs further study.
19
Kolodezhnaya, E. V., I. V. Shadrunova e M. S. Garkavi. "Potential of Using Waste Incinerator Slag to Sequester Carbon Dioxide". Ecology and Industry of Russia 26, n. 3 (5 marzo 2022): 40–45. http://dx.doi.org/10.18412/1816-0395-2022-3-40-45.
Testo completoAbstract (sommario):
Data on conditions and volumes of slag formation resulting from waste fuel incineration is presented, technological schemes of processing and disposal are made including carbon dioxide fixation. Results of gravitational-magnetic slag enrichment to process polymetallic bulk concentrate are achieved. Granulometric, chemical and mineral composition of fresh and unused slags resulting from waste incineration were measured. Differences of slag material composition depending on grain-size class were identified. Reaction equations of slag carbonization were studied. Reactivity of slag phases with respect to carbonic oxide was assessed. Carbonization potential of unused and fresh slags resulting from waste incineration was calculated depending on grain-size class.
20
Kenzhaliyev, B. K., S. A. Kvyatkovskiy, M. A. Dyussebekova, A. S. Semenova e D. Nurhadiyanto. "Analysis of Existing Technologies for Depletion of Dump Slags of Autogenous Melting". Kompleksnoe Ispolʹzovanie Mineralʹnogo syrʹâ/Complex Use of Mineral Resources/Mineraldik Shikisattardy Keshendi Paidalanu 323, n. 4 (23 maggio 2022): 23–29. http://dx.doi.org/10.31643/2022/6445.36.
Testo completoAbstract (sommario):
Pyro-metallurgy of copper production is characterized by the output of copper slag, which is regarded as a kind of solid waste. Moreover, this slag is identified as hazardous because it contains impurities, like Pb, As, and Cu. Obtaining dump slags in autogenous processes does not always meet the requirements of effective technologies, most often slags contain more than 1.0% of copper and need to be depleted. This work is presented a brief analysis of existing technologies used for copper slag depletion. The analysis of the existing technologies for the depletion of autogenous smelting dump slags showed that the most promising option seems to be the depletion of copper slags in one PV unit since by improving the process itself, by changing the unit design, it is possible to achieve technologically complete production of matte and dump slag with low copper content. There were proposed two technologies of improvement: electro-heating of slag siphon using the graphite electrodes and depletion process in two-zone PV furnace.
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Pribulová, A., P. Futáš, A. Kmita, D. Márasová e M. Holtzer. "Impact of electro slag remelting on 14 109 steel properties". Archives of Metallurgy and Materials 62, n. 1 (1 marzo 2017): 181–85. http://dx.doi.org/10.1515/amm-2017-0025.
Testo completoAbstract (sommario):
Abstract The Electro Slag Remelting (ESR) is one of the remelting processes in the field of metal refinery. In this process, the slag plays various roles, such as heat generation, protection of melt, and chemical refining. The main objective of the experiments described in this article was to identify the most appropriate slag composition for the electro slag remelting of the steel in order to achieve the chemical composition compliant with the standard applicable to the given steel, minimum sulphur content, minimum contents of oxide and sulphide inclusions, as well as mechanical properties corresponding to the standard applicable to the steel STN 14 109. Ten electrodes were remelted, whereas the remelting was carried out under 8 slags. The used slags containing 70% of CaF2 and 30% of Al2O3 with different addition of CaO, the slags consisted of the same components as previous slags, whereas the ratio of individual components was 1:1:1, and with SiO2 and MgO and slag without Al2O3. With regard to all the above mentioned facts, the slag types which may be regarded as the most appropriate for the STN 14 109 steel remelting are the basic slags containing 70% of CaF2 - 30% of Al2O3 with added 30 and 45 weight % of CaO.
22
Shubina, Marianna V., e Elena S. Makhotkina. "Analysis of the Leaching Stage Effect on the Vanadium Extraction from Technogenic Raw Materials". Materials Science Forum 1052 (3 febbraio 2022): 462–66. http://dx.doi.org/10.4028/p-27ijw5.
Testo completoAbstract (sommario):
As a result of titanomagnetite iron ore processing, technogenic waste is formed in the form of vanadium-containing slags. The industrial processing of these slags is important to improve the environmental situation in industrial regions and expand vanadium raw material base. The study purpose was the vanadium extraction from slags of titanomagnetite ore processing (ITmk3 process slag and JSC “EVRAZ NTMK” slag) in the soluble vanadate form. Research tasks: hydrometallurgical vanadium extraction from slags of different chemical composition using soda technology; determination of the leaching mode effect (temperature and duration) on the vanadium extraction degree. Experimental samples in the form of slag and soda Na2CO3 mixture were processed to oxidative roasting and subsequent water leaching at different temperatures from 50 °C to 80 °C for 1, 2 and 3 hours. In the resulting solutions the vanadium content was determined with X-ray fluorescence spectroscopy (XRF). Analysis of the research results showed that the slag chemical composition and the water leaching conditions had a significant effect on vanadium extraction degree. The vanadium extraction degree from the JSC “EVRAZ NTMK” slag was 2 – 2.5 times higher than from the ITmk3 process slag after applying the same leaching modes. The highest degree of vanadium extraction was obtained after leaching at a temperature of 80 °C for 3 hours. These leaching modes increased the vanadium extraction degree from the JSC “EVRAZ NTMK” slag to 65 – 87%, and from the ITmk3 process slag to 31 – 33%.
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Liu, Yu, Zhao Zhang, Guangqiang Li, Yang Wu, Xijie Wang e Baokuan Li. "Effect of SiO2 containing slag for electroslag remelting on inclusion modification of 42CrMo steel". Metallurgical Research & Technology 116, n. 6 (2019): 627. http://dx.doi.org/10.1051/metal/2019063.
Testo completoAbstract (sommario):
Five heats were carried out to study the effects of SiO2 containing slag for electroslag remelting (ESR) on inclusion characteristics of 42CrMo steel. Fluoride vaporization at elevated temperature from slags was also explored by thermogravimetric analysis. The results show that fluoride vaporization is dominated by slag viscosity and component activities in the melt. Slag composition has an important effect on the composition of the oxide inclusion. For 70 wt% CaF2–30 wt% Al2O3 slag, the compositions of oxide inclusions in remelted steel show no obvious differences compared with the virgin steel. Whereas, SiO2 content in oxide inclusions of steel processed by slag bearing SiO2 show an increasing trend with increase of SiO2 content in 50 wt% CaF2–CaO–SiO2 slag, and the MgO · Al2O3 inclusions are modified to (Al,Ca,Mg,Si)O inclusions with low melting temperature. Al2O3 contents in oxide inclusions are also closely related to the Al2O3 concentration in the molten slag, which increase with the addition of Al2O3 in slag bearing SiO2. In testing various slags, the incorporation of slag T2 with 50 wt% CaF2–30 wt% CaO–20 wt% SiO2 shows the highest cleanliness in remelted steel. This implies that slag T2 can be a promising slag for ESR process of alloy steel requiring Al content refinement due to less fluoride vaporization from slag and better inclusions modification.
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Togobitskaya, D. N., A. I. Belkova, D. A. Stepanenko, N. A. Tsyupa e Yu M. Likhachev. "Prediction of the properties of blast furnace slag in modern conditions of blast furnaces of Ukraine". Fundamental and applied problems of ferrous metallurgy, n. 32 (2018): 118–36. http://dx.doi.org/10.52150/2522-9117-2018-32-118-135.
Testo completoAbstract (sommario):
The aim of the work is the development of models for predicting the properties of final blast-furnace slags for the rapid assessment of the slag regime and the development of sound management recommendations when using various additives in the operating conditions of blast furnaces in Ukraine. A two-stage approach to calculating the properties of blast-furnace slag is proposed: according to the model of a “homogeneous” melt and taking into account its heterogeneity. A predictive model has been developed for calculating the viscosity of a «homogeneous» slag by including the integral parameter of the slag melt parameter e in the model structure, which takes into account the individual effect on the viscosity of each component of the slag composition. The current production data of the chemical composition of the final slag shows the effect of the magnesia content, alkaline compounds, basicity, Al2O3/MgO ratio on the calculated viscosity of the slags. For various operating conditions of blast furnaces, it has been shown that, due to incomplete combustion of coke and pulverized coal, the viscosity of slags increases by 1.5–2 times and their melting temperatures by 30–500C. Comparative analysis of the calculated properties of slag for different operating conditions of 3 furnaces in Ukraine confirms the appropriateness of using a complex of predictive models for the rapid assessment of the technological properties of slag, which makes it possible to choose a rational slag mode in modern conditions of blast smelting.
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Deng, Zhi Hao. "Influence of P2O5 and Al2O3 on Mineral Formation in Converter Slag". Applied Mechanics and Materials 477-478 (dicembre 2013): 1273–77. http://dx.doi.org/10.4028/www.scientific.net/amm.477-478.1273.
Testo completoAbstract (sommario):
Converter Slag is a by-product during steelmaking. Reusing the slag as Portland cement material can be regarded as a way to reduce environmental pollution. However, the poor grindability caused by complex chemical composition of the slag makes it very difficult to be used in cement industry. To better understand its grindability, the mineral characteristic of converter slag was investigated in this paper. Experimetal slags of CaO-MgO-SiO2-Fe2O3, CaO-MgO-SiO2-Fe2O3-P2O5 and CaO-MgO-SiO2- Fe2O3-P2O5-Al2O3 were synthetized according to physical and chemical properties of actual converter slag. The mineral structures of these slags were analyzed by SEM and EDS. The results show that actual and synthetic slags have mainly three mineral, where dicalcium silicate with little phosphorus presented dark gray, periclase presented black and the matrix phase of dicalcium ferrite. Moreover, phosphorus largely dissolves in the 2CaO∙SiO2 in the form of 3CaO∙PO4, and the other minerals don’t contain phosphorus. A Little aluminum has a little influence on the mineral formation of the slag.
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Xie, Sui, Xinhua Yuan, Fupeng Liu e Baojun Zhao. "Control of Copper Content in Flash Smelting Slag and the Recovery of Valuable Metals from Slag—A Thermodynamic Consideration". Metals 13, n. 1 (11 gennaio 2023): 153. http://dx.doi.org/10.3390/met13010153.
Testo completoAbstract (sommario):
To determine slag properties and the factors influencing these properties for optimization of operating conditions in the copper flash smelting process, the composition and microstructures of the quenched smelting and converting slags have been analyzed. Thermodynamic software FactSage 8.2 has been used to investigate the effects of matte grade, SO2 partial pressure, and the Fe/SiO2 ratio on the liquidus temperature and the copper content of the smelting slag. The possibility to recover valuable metals from the smelting and converting slags through pyrometallurgical reduction by carbon is also discussed. It was found that the flash smelting slag temperature is usually higher than its liquidus temperature and the copper (1.2% Cu) is mainly present in the slag as dissolved copper. In the copper flash smelting process, the copper content in the slag can be decreased by decreasing the Fe/SiO2 ratio and temperature. In pyrometallurgical slag reduction, most Cu, Mo, and Ni can be recovered as an alloy. The conditions of recovery such as the ratio of smelting slag to converting slag, temperature, and reduction extent have been discussed.
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Ogirigbo, O. R., e I. Inerhunwa. "Strength and Durability Performance of Slag Blended Cements in High Temperature Environments". July 2017 1, n. 2 (luglio 2017): 265–72. http://dx.doi.org/10.36263/nijest.2017.02.0042.
Testo completoAbstract (sommario):
In this study, two slags of different chemical compositions were blended with a CEM I 52.5R-type Portland cement at 30% wt. replacement ratio. Various tests such as strength, water and chloride ion permeability test were carried out at a high temperature of 38°C. The performances of the slag blends were measured against that of a CEM I 42.5R-type Portland cement. The results obtained showed that the performances of the slag blends were better than that of the CEM I 42.5R cement. In comparing the performances of the slags, the blend prepared from slag 1 had higher strengths and better transport properties than that prepared from slag 2, and this was attributed to the higher basicity and alumina content of slag 1. The findings of the study suggest that in tropical/ high temperature environments, the chemical composition of the slags play an important role in determining their performance.
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Shyrokykh, Tetiana, Xingwen Wei, Seshadri Seetharaman e Olena Volkova. "Vaporization of Vanadium Pentoxide from CaO-SiO2-VOx Slags During Alumina Dissolution". Metallurgical and Materials Transactions B 52, n. 3 (29 marzo 2021): 1472–83. http://dx.doi.org/10.1007/s11663-021-02114-9.
Testo completoAbstract (sommario):
AbstractThe vaporization of vanadium pentoxide from CaO-SiO2-VOx ternary slags using different gas treatment regimens and parallel vacuum gas extirpation to treat V-bearing slags at 1873 K has been developed in the present study. The novelty of the present study is to monitor the effect of parallel alumina dissolution on the vaporization phenomenon. Vanadium pentoxide has high vapor pressure at the temperatures over 1500 K. When CaO-SiO2-VOx ternary slags, kept in dense alumina crucibles, are injected with oxygen, V2O5 gas bubbles are formed which are forced out by using vacuum extirpation. The vanadium pentoxide could be then collected in the exhaust gases. The mechanism of the process phenomenon is described as the formation of V2O5 gas phase resulting from the oxidation of the lower-valent oxides present in the slag. This gas phase would form microbubbles in the molten slag bulk phase due to low surface tension between the gas phase and the slag, thereby increasing the contact surface. At the same time, the crucible material would dissolve in the slag causing an increase in the slag viscosity. Due to the high slag viscosity of the bulk slag, these microbubbles formed would have difficulty in coalescing and reaching the slag surface. The escaping of the bubbles into the gas phase is enabled by the vacuum extirpation.
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Anatoliy, Shevchenko, Volodymyr Kislyakov, Borys Dvoskin, Ivan Manachyn e Kostyantin Chubin. "STUDY OF CHANGES OF THE SULFUR CONTENT IN CAST IRON AND THE COMPOSITION OF SLAG IN TECHNOLOGICAL PROCESSING DURING THE PREPARATION OF CAST IRON FOR THE CONVERTER MELTER". Modern Problems of Metalurgy, n. 25 (8 aprile 2022): 201–19. http://dx.doi.org/10.34185/1991-7848.2022.01.17.
Testo completoAbstract (sommario):
The article analyzes the change in the sulfur content of cast iron and the composition of slag in the technological chain of preparing cast iron for converter smelting. On the basis of the results of the conducted research, technical solutions and technological techniques aimed at eliminating cast iron resulfurization were developed and recommended. Spot probe scanning of bucket slag samples showed that in the slag phase, along with CaO∙SiO2∙Al2O3 type systems with different ratios of components containing 0.2–3.5% sulfur, CaxSiyAlz type systems containing up to 1% sulfur were found; in "beads" the sulfur content varies no more than 0.1 - 0.85% and in the form of sulfides of the (Fe, Mn)S type, mainly MnS, and in the non-metallic inclusions of "beads" the sulfur content is no more than 15 - 30%. Studies of the compositions of dry, friable and liquid glassy ladle slags after desulfurization showed that they do not change the phase composition, but unlike the original ladle slags, in the slag phase of such slags there are mainly CaO·SiO2·Al2O3·MgO type systems, enriched with magnesium oxides with variable ratio of components. At the same time, sulfur in the slag phase of dry slags is mainly in the form of (Ca, Mn, Mg, Al, Si)S complexes, and in the slag phase of liquid slags it is mainly in the form of MnS and less often in the form of (Ca, Mn)S complexes. According to the results of industrial experiments carried out at a number of enterprises in Ukraine and China, it was established that in order to limit the introduction of sulfur into converter steel with slag at the level of ≤0.002%, the remaining ladle slag after desulfurization should not exceed 0.5-0.7 kg/t of cast iron.
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Long, Xiao, Wenbo Luo, Jun Lv, Falou Chen, Xiang Li e Shaolei Long. "Titanium Removal from Metallurgical-Grade Silicon Melts Using High-Basicity Index Slag and Carbon Dioxide Injection". Metals 12, n. 6 (11 giugno 2022): 1004. http://dx.doi.org/10.3390/met12061004.
Testo completoAbstract (sommario):
In this study, novel slags with a high basicity index were used to refine silicon melts with carbon dioxide injection to effectively remove Ti from metallurgical-grade silicon. Different compositions of the initial slag were used, and silicon samples were obtained during the refining. The results indicate that the Ti-removal rate initially increased with an increase in the basicity index, and it decreased after the basicity index exceeded 1.4. During the refining, silicon emulsification was observed at the slag–silicon interface, which was restricted by the increased basicity index of slags. Impurities that were concentrated in silicon droplets near the slag–silicon interfaces were oxidized, wetted by slags, and transferred to the slag phase. After 15 min of refining, up to 59 wt% of Ti in silicon could be removed and the Ti-concentrating phase in the slag contained 2.05 wt% of Ti. The results of this study provide a reference for low-cost Ti removal from metallurgical-grade silicon using a refining method.
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Li, Long, Da De Zhang, Jian Hua Zeng e Yong Chen. "Effects of SiO2 and Al2O3 Contents of Converter Slag on its Sticking to MgO-C Brick". Advanced Materials Research 634-638 (gennaio 2013): 3134–37. http://dx.doi.org/10.4028/www.scientific.net/amr.634-638.3134.
Testo completoAbstract (sommario):
Using ladle slag, ferrovanadium smelting slag as well as slagging materials as starting materials, the converter slags with SiO2 contents of 11.3% to 2.6%, Al2O3 contents of 3.3% to 19.1% were prepared and some cylinder-shaped MgO-C samples were processed to fulfill slag sticking tests conducted at 1600°C in atmosphere furnace. The research results show that the amount of slag adhesion decreases with a reduction of SiO2 content and an increase of Al2O3 content in slag, owing to larger viscosity and higher foam index of molten slag. To control the variations of SiO2 and Al2O3 contents in converter slag is conducive to better slag splashing. Furthermore, the mechanism of SiO2 and Al2O3 contents of converter slag impacted on slag sticking to MgO-C brick has been further discussed.
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Liao, Jie Long, Zhao Hui Zhang, Jian Tao Ju e Fu Cai Zhao. "Comparative Analysis of Steel Slag Characteristics and Treatment Process". Advanced Materials Research 834-836 (ottobre 2013): 378–84. http://dx.doi.org/10.4028/www.scientific.net/amr.834-836.378.
Testo completoAbstract (sommario):
Steel slag is hydraulic cementing material, which is mainly applicable approach to the production of cement, admixture of high performance concrete, road engineering. But as a result of hydration expansion of the free calcium oxide and free magnesium oxide and dicalcium silicate morphological changes which is contained in slag cause poor stability of steel slag used in engineering, the steel slag utilization is very low. Therefore, the key technology of steel slag treatment process is to improve the stability of steel slag. Steel slag is alkaline slag, with lower temperature, the viscosity increases sharply, the liquidity variation, it is one of the important factors affect the steel slag processing, According to the need for different liquidity of steel slag to choose the corresponding steel slag treatment technology. Tank-type hot disintegrating, Rotary cylinder technology processing available to small particle size, good steel slag separation, active promotion of slags, conducive to the comprehensive utilization of steel slag.
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Liu, Zhaoyang, Yuqing Gao, Songyang Pan, Ruinan Zhang, Wei Gao, Tianpeng Wen, Beiyue Ma e Jingkun Yu. "The influence of vanadium and titanium oxides in slag on the wetting and corrosion of dense Al2O3 ceramics". Processing and Application of Ceramics 18, n. 1 (2024): 65–76. http://dx.doi.org/10.2298/pac2401065l.
Testo completoAbstract (sommario):
The present study investigates the wetting and corrosion behaviour of slags on dense Al2O3 ceramics, focusing on the influence of varying vanadium- and titanium oxide content. Physicochemical properties of the slag were assessed by measuring wetting angles, heights and diameters of the molten slags on the alumina at different temperatures. Microscopic observations and elemental composition analysis were conducted on the interface between the corroded Al2O3 ceramics and the slags. Our findings demonstrated that the V2O3 addition in the slag leads to its oxidation to V2O5, which further reacts with Fe2O3 and MnO to form low melting point phases such as FeVO4 and MnVO6. Consequently, the melting point of the slag decreases significantly, resulting in a decreased wetting angle with the Al2O3 ceramics. The presence of unsaturated alumina in the slag leads to the dissolution of aluminium ions from the ceramics into the slag, which reacts with Fe2O3 and MnO to form spinel phases, contributing to material loss of the ceramics. Infiltration of the slag into the Al2O3 predominantly occurs through the alumina grain boundaries. Two types of infiltration are identified: one involving reactions with alumina to form low melting point phases like Fe2O3 and the other involving inherent low melting point phases such as MnVO6. In contrast, the penetration of SiO2 into the alumina substrate is limited. Additionally, the dissolution of Al2O3 into the slag creates pathways for further infiltration. This study highlights the significant influence of Ti and V content on the physicochemical properties of the slag and provides insight into the corrosion mechanism of Al2O3 ceramics by Ti and V containing slags.
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CHEN, E., e K. COLEY. "GAS SLAG REACTION KINETICS IN SLAG CLEANING OF COPPER SLAGS". Canadian Metallurgical Quarterly 45, n. 2 (gennaio 2006): 167–74. http://dx.doi.org/10.1179/cmq.2006.45.2.167.
Testo completo
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Geldenhuys, I. J., Q. G. Reynolds e G. Akdogan. "Evaluation of Titania-Rich Slag Produced from Titaniferous Magnetite Under Fluxless Smelting Conditions". JOM 72, n. 10 (3 agosto 2020): 3462–71. http://dx.doi.org/10.1007/s11837-020-04304-3.
Testo completoAbstract (sommario):
Abstract Titanium-bearing magnetite ore is generically defined as magnetite with > 1% titanium dioxide (TiO2) and is usually vanadium-bearing. The iron and titanium occur as a mixture of magnetite (Fe3O4) and ilmenite (FeTiO3) with vanadium oxide usually occurring within the solid solution of the titanium-bearing magnetite phase. These ores are currently widely processed in blast furnaces via modified ironmaking processes. Typically, vanadium is recovered as a by-product from the ironmaking process, while the diluted titania slag is stockpiled. Fluxless smelting in a direct-current open-arc furnace is proposed as an opportunity to improve iron and vanadium recovery and potentially unlock the titanium as a slag product. Slags produced from a pilot study are compared to industrial slags produced from ilmenite. The findings from the pilot test show that slag produced under fluxless smelting conditions in an open-arc electric furnace is remarkably similar to industrial ilmenite slags. The test conditions were varied to evaluate the slag and metal composition, and furnace operation, under increasing reducing conditions. The study showed that the slag and metal product was remarkably similar to industrial slag produced from ilmenite.
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Stepanenko, D., e D. Togobitska. "Regarding the interaction and capture of metal droplets by blast furnace slag". Metaloznavstvo ta obrobka metalìv 30, n. 2 (28 giugno 2024): 3–15. http://dx.doi.org/10.15407/mom2024.02.003.
Testo completoAbstract (sommario):
The mechanism of capture of metal drops by the slag melt was investigated using blast furnace slag as an example. The role of the viscosity of the blast furnace slag in reducing iron loss at the output from the blast furnace is shown. Reducing the viscosity of slags contributes to the rapid settling of small drops of cast iron in the slag volume. It is noted that the CaO/SiO2 ratio is an important parameter that changes the viscosity of blast furnace slag. To ensure the minimum viscosity of blast furnace slag, it is necessary to establish the optimal chemical composition of the slag, in particular the CaO/SiO2 ratio. A study of the temperature dependence of the viscosity of blast furnace slag melts was carried out using the method of estimating the content of the solid phase in the melt during its cooling. Calculations of the volume fraction of the solid phase for blast furnace slags were performed. An increase in the CaO/SiO2 ratio in slags leads to an increase in their crystallization ability. The microstructure and chemical composition of individual phases of a blast furnace slag sample were studied using scanning electron microscopy (SEM). It was established that the experimental slag contained at least three phases. The main (matrix) phase was an amorphous phase, which contained mainly SiO2 and Al2O3. The volume of the matrix phase contained interspersions of the crystalline phase of different sizes, which mainly included CaO and SiO2. In the volume of the crystalline phase, a metallic phase was found, which consisted mainly of Fe and Mn and had a regular rounded shape. The mechanism of capture of a metal droplet by slag is described. The metal drop serves as a frame (center) for the nucleation of the crystalline phase in the slag volume, as its surface energy decreases at the "metal drop - slag" interface. An increase in the mass of the crystalline phase around the metal drop leads to an increase in its lifting force and capture of the metal drop. Keywords: blast furnace slag, viscosity, metal loss, crystallization, scanning electron microscopy.
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Zhao, Shuo, Zushu Li, Renze Xu, Darbaz Khasraw, Gaoyang Song e Dong Xu. "Dissolution Behavior of Different Inclusions in High Al Steel Reacted with Refining Slags". Metals 11, n. 11 (9 novembre 2021): 1801. http://dx.doi.org/10.3390/met11111801.
Testo completoAbstract (sommario):
Al2O3, Al2O3·TiN, Al2O3·MgO, and CaO·2Al2O3 are four different types of inclusions in high Al steels. To improve the steel cleanness level, the effective removal of such inclusions during secondary refining is very important, so these inclusions should be removed effectively via inclusion dissolution in the slag. The dissolution behavior of Al2O3, Al2O3·TiN, Al2O3·MgO, and CaO·2Al2O3 in CaO-SiO2-Al2O3-MgO slags, as well as the steel-slag reaction, was investigated using laser scanning confocal microscopy (LSCM) and high-temperature furnace experiments, and thermodynamic calculations for the inclusion in steel were carried out by FactSage 7.1. The results showed that Al2O3·TiN was observed to be completely different from the other oxides. The composite oxides dissolved quickly in the slags, and the dissolution time of the inclusions increased as their melting point increased. SiO2 and B2O3 in the slag were almost completely reacted with [Al] in steel, so the slags without SiO2 showed a positive effect for avoiding the formation of Al2O3 system inclusions and promoting inclusions dissolution as compared with SiO2-rich slags. The steel-slag reaction was also found to influence the inclusion types in steel significantly. Because of the rapid absorption of different inclusions in the slag, it was found that the dissolution time of inclusions mainly depends on the diffusion in the molten slag.
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Togobitskaya, D. N., A. I. Belkova, D. A. Stepanenko, N. A. Tsyupa e Yu M. Likhachev. "Development of the model complex of the expert system of control and management of the slag mode in modern mixed blast furnace conditions". Fundamental and applied problems of ferrous metallurgy, n. 34 (2020): 30–46. http://dx.doi.org/10.52150/2522-9117-2020-34-30-46.
Testo completoAbstract (sommario):
The aim of the work is to develop physicochemical bases for predicting the technological properties of finite blast furnace slags, algorithmic and software for the subsystem for diagnosing the slag regime of blast furnace smelting. Based on experimental data on the properties of natural finite blast furnace slags, predictive models for calculating the viscosity of the final slag at a temperature of 1400-1550 °C were improved by including in the model structure an integrated slag melt index of the parameter Δe, which reflects the individual effect. Using the integral parameters of the slag melt characterizing the charge state of the system Δe and the structure of the slag ρ, an equation was developed to determine the viscosity of the slag at any temperature corresponding to the slag temperature at the cast iron outlet. As a result of analytical research, a predictive model for determining the enthalpy of slag depending on the integral parameters Δe and ρ and the temperature of the melt has been developed. It is shown that the viscosity characterizes the fluidity of the slag and provides desulfurizing and drainage properties. The calculation of the viscosity for the specified production of pig iron by the chemical composition of the slag is carried out according to the basic model of slag in a conditionally "homogeneous" state and taking into account its heterogeneity. This takes into account the presence of macroheterogeneous inclusions formed when using coke with low strength characteristics and due to incomplete combustion of pulverized coal fuel in the blast furnace. The improved models for evaluating the viscosity and enthalpy of the final slag are software implemented in the new version of the «Slag» system for operational control of the slag mode of blast furnaces in Ukraine. Rapid assessment of the slag mode using the «Slag» system as part of the DCS allows you to effectively and at a modern level solve the problems of optimizing the slag mode and the quality of pig iron in modern conditions of blast furnace smelting.
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Kozin, R., L. Kuznetsova, N. Hulyanytska e I. Mossokovska. "Determination of Nitrogen Content in the Slags of CaO — Al2O3 System by Kjeldahl Method". Metrology and instruments, n. 3 (3 luglio 2019): 55–60. http://dx.doi.org/10.33955/2307-2180(3)2019.55-60.
Testo completoAbstract (sommario):
Due to the expansion of the nomenclature of steel grades in the industry and the development of new special alloys with increased strength and corrosion-resistant properties, both in the metallurgical industry and in welding, researchers are very interested in the dissolution of nitrogen in metals and slag. Gas permeability of slag is one of the reasons for the appearance of gases in both the base metal and the weld metal. It is determined by two properties: solubility and mass transfer of gases in slag. In addition, in real conditions, the process of dissolving gases in slag is influenced by the transmission of gases by convection and the initial content of gases in the slag. The transfer of gases to the metal through slag is observed mainly in electroslag processes and welding under flux when there is no direct contact of molten metal with a gas phase. To evaluate the nitrogen permeability of the slag and the mechanism of nitrogen solubility in the high alloys it is necessary to have a reliable, highly sensitive and economical method of gas analysis of nitrogen in metals and slags.
A review of nitrogen determination methods in steels is presented. The method of analysis of nitrogen in slags of the CaO — АL2O3 system by the Kjeldahl method was tested. The results of the analysis of slag compositions of the CaO — АL2O3 system allowed us to conclude that it is possible to use the Kjeldahl method (determination of nitrogen content in steels) for the determination of nitrogen content in slags. This technique and installation can be recommended for use by metallurgists and welders as a reliable, simple and inexpensive method for nitrogen content analysis in metals and slags.
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Xu, Haiqin, Shaopeng Wu, Hechuan Li, Yuechao Zhao e Yang Lv. "Study on Recycling of Steel Slags Used as Coarse and Fine Aggregates in Induction Healing Asphalt Concretes". Materials 13, n. 4 (17 febbraio 2020): 889. http://dx.doi.org/10.3390/ma13040889.
Testo completoAbstract (sommario):
Steel slag, a by-product of steelmaking, imposes lots of negative impacts on the environment. For alleviating negative impacts, more and more experiments have been carried out to explore the application possibility of steel slag. The purpose of this study is to explore the feasibility of steel slag being applied in induction healing asphalt concretes to replace coarse and fine aggregate. Surface texture and pore sizes of steel slag were firstly tested, and then steel slag and basalt asphalt mixtures modified with steel fibers were prepared. Moisture susceptibility, dynamic stability, mechanical property, thermal property, induction heating speed, natural cooling speed and healing property of the asphalt mixtures were evaluated. Results showed that steel slags had more obvious holes in the surface while the surface area is much larger than that of basalt. Furthermore, steel fibers and steel slag both have dynamic stability, and steel fibers contribute to increased moisture resistance while steel slag is not. Steel slag asphalt concrete showed better mechanical property and better capacity to store heating. Steel slag asphalt mixtures had a similar heating speed to basalt asphalt mixtures but a significantly slower cooling rate. Finally, the induction healing test and CT scanning test demonstrated that steel slag asphalt mixtures had a similar healing ability to basalt asphalt mixtures. It can be concluded that steel slags have the potential to replace the natural aggregates to be applied in induction heating self-healing asphalt concretes.
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Kim, Taehyoung, Seonhee Kim, Hyunji Tak, Kyeongtae Kim, Chul-Woo Chung e Minhee Lee. "Mechanisms at Different pH for Stabilization of Arsenic in Mine Tailings Using Steelmaking Slag". Minerals 10, n. 10 (11 ottobre 2020): 900. http://dx.doi.org/10.3390/min10100900.
Testo completoAbstract (sommario):
The mechanisms at different pH for the stabilization of arsenic (As) in mine tailings (MTs) using steelmaking slag were investigated using laboratory experiments. Two types of steelmaking slag were used in the experiments. Ca-slag has high pH and high calcium oxide content due to its short period of aging. In contrast, Fe-slag is oxidized for a long time and is richer in Fe than in Ca. The As-contaminated MTs were taken from a tailing-storage dam around an abandoned gold mine in Korea. The tailings had an average As concentration of 2225.3 mg/kg. The As-removal batch experiment was performed to investigate the As-removal characteristics of the steelmaking slag. From SEM/EDS analyses after each batch experiment, Ca-As bearing precipitates were broadly found on the surface of Ca-slag particles and the final pH of the solution increased to 12.3. However, for Fe-slag, the As was locally found as forms adsorbed to the surface of Fe and Mn oxides contained in the Fe-slag particles. The final pH of this solution was 8.4. The efficiency of removal of As from water using the Ca-slag was >97% and that with Fe-slag was 79%. This suggests that As ions in solution were removed by Ca-(co-)precipitation (which occurs comprehensively on the Ca-slag surface), or by restrictive adsorption of Fe- and Mn-oxides (on limited parts of the Fe-slag). To determine the efficiency of As-extraction reduction from MTs using steel slags, arsenic-extraction batch experiments with two slags were performed under acidic conditions, simulating the leaching environment formed around a mine tailing storage dam. The As concentration in the extracted solution was decreased by 69.9% (even at pH 2) after the addition of 5% Fe-slag. However, when 5% Ca-slag was added, the As concentration decreased by 42.3% at pH 2. These results suggest that Fe-rich steel slag can be more effective than Ca-rich steel slag as a stabilizer for As in contaminated mine tailings at low pH.
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Kudyba, Artur, Shahid Akhtar, Inge Johansen e Jafar Safarian. "Aluminothermic Reduction of Manganese Oxide from Selected MnO-Containing Slags". Materials 14, n. 2 (13 gennaio 2021): 356. http://dx.doi.org/10.3390/ma14020356.
Testo completoAbstract (sommario):
The aluminothermic reduction process of manganese oxide from different slags by aluminum was investigated using pure Al and two types of industrial Al dross. Two types of MnO-containing slags were used: a synthetic highly pure CaO-MnO slag and an industrial high carbon ferromanganese slag. Mixtures of Al and slag with more Al than the stoichiometry were heated and interacted in an induction furnace up to 1873 K, yielding molten metal and slag products. The characterization of the produced metal and slag phases indicated that the complete reduction of MnO occurs via the aluminothermic process. Moreover, as the Al content in the charge was high, it also completely reduced SiO2 in the industrial ferromanganese slag. A small mass transport of Ca and Mg into the metal phase was also observed, which was shown to be affected by the slag chemistry. The obtained results indicated that the valorization of both Al dross and FeMn slag in a single process for the production of Mn, Mn-Al, and Mn-Al-Si alloys is possible. Moreover, the energy balance for the process indicated that the energy consumption of the process to produce Mn-Al alloys via the proposed process is insignificant due to the highly exothermic reactions at high temperatures.
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Wiraseranee, C., T. Yoshikawa, T. H. Okabe e K. Morita. "Effect of Al2O3, MgO, and CuOx on the dissolution behavior of rhodium in the Na2O-SiO2 slags". Journal of Mining and Metallurgy, Section B: Metallurgy 49, n. 2 (2013): 131–38. http://dx.doi.org/10.2298/jmmb121221018w.
Testo completoAbstract (sommario):
Aiming to optimize rhodium recovery in the high temperature recycling process by minimizing rhodium loss into slags in an oxidizing atmosphere by controlling slag composition, the effects of representative slag components, such as Al2O3, MgO, and CuOx, on the dissolution behavior of rhodium into the Na2O-SiO2 slags was investigated. The solubility of rhodium was measured by equilibrating the sodium silicate based slags with pure solid rhodium at 1473 K in air. Considering that rhodium dissolved into slags as RhO1.5, the effect of the oxide addition on the activity coefficient of RhO1.5 in slags was determined. The dissolution of rhodium in slags was suppressed by the addition of Al2O3 and MgO, where Al2O3 behaved as an acidic oxide and MgO behaved as a diluent of slag basicity at a fixed Na2O/SiO2 ratio of 0.97. The content of copper in solid rhodium equilibrated with the CuOx bearing slags slightly increased with increasing content of CuOx, and CuOx was found to slightly enhance the dissolution of rhodium. Rhodate capacity of all slag systems increased with increasing optical basicity, suggesting that the correlation between rhodate capacity and the optical basicity enables the estimation of the content of rhodium in slags of which thermodynamic properties of rhodium are not clarified.
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Yakubov, M. M., M. M. Yoqubov, D. B. Kholikulov e M. S. Maksudhodjaeva. "Depletion of converter slags to waste in the Vanyukov furnace during pyrometallurgical copper production at JSC Almalyk MMC". Kompleksnoe Ispolʹzovanie Mineralʹnogo syrʹâ/Complex Use of Mineral Resources/Mineraldik Shikisattardy Keshendi Paidalanu 331, n. 4 (25 gennaio 2024): 60–68. http://dx.doi.org/10.31643/2024/6445.39.
Testo completoAbstract (sommario):
The article shows the possibility of involving man-made formations in the pyrometallurgical production of copper in the form of slag and clinker-zinc production for the purpose of comprehensive extraction of non-ferrous and precious metals from them at Almalyk MMC JSC. Clinker, a technogenic waste from zinc production, contains a significant amount of reducing elements in the form of metallic iron and carbon, as well as gold in the amount of 2.3 g/t and silver 250 g/t. In research, clinker works as a reducer of magnetite contained in the converter slag during its depletion and in the process of depletion (reduction) of the converter slag, noble metals are extracted into matte, and then into blister copper up to 95-98%. Converter slags from copper production of Almalyk MMC JSC contain 2.0-3.5% copper, and they, as a circulating product, are depleted in a reverberatory furnace with copper extraction of 75%. To increase the yield of copper from converter slag in Vanyukov furnaces, it is necessary to first deplete the converter slag in reduction processes and then transfer it for processing. It was found that using clinker, a technogenic waste from zinc production with a particle size of +5 - -10 mm, the recovery of converter slag in a converter from magnetite to wustite using the developed technology in 10-15 minutes exceeded more than 50.0% (the amount of magnetite decreased from 21.9 % to 9.8%). As a result of processing recovered converter slags in the Vanyukov furnace, it was possible to reduce the copper content in converter slags of copper production from 2.2-3.5% to 0.58-0.72% in waste slag. To increase the yield of copper from converter slag in the reverberatory and Vanyukov furnaces, it is necessary to first deplete the converter slag in reduction processes and then transfer it for processing.
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Malzev, K. Y., O. B. Kolmachikhina e Sergey E. Polygalov. "Research for the Processing of Stale Slag from the Ural Region by the Pyro-Metallurgical Method". Materials Science Forum 989 (maggio 2020): 406–10. http://dx.doi.org/10.4028/www.scientific.net/msf.989.406.
Testo completoAbstract (sommario):
Pyro-metallurgical copper production is characterized by the formation of a large amount of slags. The copper content in the smelt slag is 0.5-2 %, in the vessel slag - about 5%, which often exceeds the copper content in the mined ores (about 1%). This makes depletion of slag a necessary operation in the pyro-metallurgical production of copper. In addition, about 110 million tons of copper slags have been accumulated in the dumps of copper factories in the Urals. The processing of these slags which contain up to 2.5% Cu is a very important task, the solution of which will allow extracting copper and reducing the areas occupied by the dumps.
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Chen, Chunlin, Ling Zhang e Jean Lehmann. "Thermodynamic Modelling of Phosphorus in Steelmaking Slags". High Temperature Materials and Processes 32, n. 3 (14 giugno 2013): 237–46. http://dx.doi.org/10.1515/htmp-2012-0129.
Testo completoAbstract (sommario):
AbstractThe published phase diagrams of some key P2O5-containing systems which are relevant to the steelmaking slag and the available experimental data on phosphorus partitioning between liquid iron and slags consisting of SiO2-Al2O3-Fe2O3-FeO-MnO-MgO-CaO-Na2O have been reviewed and assessed. A set of data under carefully controlled experimental conditions, which was considered to be more reliable based on the assessment, was selected for optimising the generalised central atom (GCA) model parameters of phosphorus-containing slag systems. The developed model database is proved to be able to represent the liquidus temperature of some key P2O5-containing systems and the phosphorus distribution ratio between the steelmaking slags and liquid iron reasonably well. With the developed GCA model database, the dephosphorization reaction in the steelmaking process was modelled under various operating conditions such as slag chemistry and temperature. The results show that the phosphorus distribution ratio between the slags and liquid iron displays a maximum point with variation of the FeOx content in the slag. It also shows that the phosphorus deportment to the slag is favored by decreasing the operating temperature and MgO content, and increasing the CaO/SiO2 ratio in the slag. Comparison with the model of the phosphorus distribution data from a commercial BOS furnace shows that operating conditions do not permit to reach P equilibrium contents. The dis-equilibrium degree of P was found to be increased with increasing slag viscosities.
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Zhang, Xiaomeng, Ziwen Yan, Zhiyin Deng e Miaoyong Zhu. "Effect of TiO2 Addition on the Melting Behaviors of CaO-SiO2-30%Al2O3-5%MgO System Refining Slags". Metals 13, n. 2 (20 febbraio 2023): 431. http://dx.doi.org/10.3390/met13020431.
Testo completoAbstract (sommario):
To improve the yield of titanium alloy, a certain amount of TiO2 can be added to the refining slag system of Ti-bearing steel grades. With the aim of understanding the effect of TiO2 addition on the melting behaviors of CaO-SiO2-30%Al2O3-5%MgO refining slags, the melting points of the slags and the phases in the slags are herein studied at different temperatures in the laboratory. It is found that with the increase in TiO2 content (0~10%) in slag, the melting point of the slags drops first, and then rises. The effect of slag basicity (R = w(CaO)/w(SiO2), 2~10) shows a similar tendency. The TiO2 content and slag basicity evidently affect the precipitated phases in the slags at a lower temperature (e.g., 1310 °C). With the increase in basicity, the liquid areal fraction increases first, and then decreases. Moreover, the CaO-TiOx-Al2O3 phase (CTA) and its TiOx content show a declining trend at 1310 °C. When R = 10, large amounts of solid calcium aluminates are precipitated. With TiO2 addition in the slags, the TiOx contents in both liquid and CTA phases increase. Excessive TiO2 addition (e.g., 10%) leads to the large precipitation of CTA, as well. To improve the melting properties of the slag and the yield of Ti alloys during the refinement of Ti-bearing steel grades, a small TiO2 addition (e.g., 5%) may be considered.
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Kero Andertun, Jakob, Pasi Peltola, Caisa Samuelsson e Fredrik Engström. "Long-Term Leaching Effects on CaO-Modified Iron Silicate Slag". Minerals 12, n. 11 (14 novembre 2022): 1442. http://dx.doi.org/10.3390/min12111442.
Testo completoAbstract (sommario):
Granulated iron silicate slag, a by-product of pyrometallurgical copper extraction, has excellent properties for construction applications. Slag modification with CaO enhances the application properties regarding pozzolanic reactivity, potentially extending slag use in the future. The slags’ short-term leaching behavior has already been investigated with promising results, while the long-term leaching effects are less studied. Therefore, this study aims to determine the long-term leaching effects on CaO-modified iron silicate slags. The CaO-modifications were conducted during full-scale slag treatment operation. The slags were characterized and leached, and the remaining slags were investigated regarding the formation of secondary phases. The long-term leaching of main and trace elements was determined over 30 days using a dynamic leaching method corresponding to an extended time period. The leaching tests showed increased leaching of the main slag elements (Si, Ca). Zn and Cu showed peak leaching after four days of leaching, and the leaching of As and Sb decreased with the increasing CaO content in the samples. After dynamic leaching, secondary phases formed on the Cu-containing inclusions on the sample surfaces. Independent of the CaO content, the leaching of Cu was increased when subjected to external acidic and oxidating conditions using static pH titration at pH 5 in dilute nitric acid.
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Kasina, Monika, Piotr R. Kowalski e Marek Michalik. "Mineral carbonation of metallurgical slags". Mineralogia 45, n. 1-2 (1 giugno 2015): 27–45. http://dx.doi.org/10.1515/mipo-2015-0002.
Testo completoAbstract (sommario):
Abstract Due to increasing emissions of greenhouse gases into the atmosphere number of methods are being proposed to mitigate the risk of climate change. One of them is mineral carbonation. Blast furnace and steel making slags are co-products of metallurgical processes composed of minerals which represent appropriate source of cations required for mineral carbonation. Experimental studies were performed to determine the potential use of slags in this process. Obtained results indicate that steel making slag can be a useful material in CO2 capture procedures. Slag components dissolved in water are bonded as stable carbonates in the reaction with CO2 from ambient air. In case of blast furnace slag, the reaction is very slow and minerals are resistant to chemical changes. More time is needed for minerals dissolution and release of cations essential for carbonate crystallisation and thus makes blast furnace slags less favourable in comparison with steel making slag.
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Kong, Dezhi, Jiahui Zou, Meizhu Chen, Jun Xie e Xuanwen Gou. "Sustainable Application of Pyrolytic Oxygen Furnace Slag in Cement-Stabilized Macadam: Volume Stability, Mechanical Properties, and Environmental Impact". Sustainability 16, n. 10 (9 maggio 2024): 3965. http://dx.doi.org/10.3390/su16103965.
Testo completoAbstract (sommario):
As an industrial waste, basic oxygen furnace (BOF) slag is an ideal substitute for natural rubble and sand. However, its potential instability of volume restricts the application of the BOF slag in engineering. This study aims at investigating the volume stability and mechanical properties of BOF slag and its application as an aggregate in cement-stabilized macadam. As part of this research, the physicochemical properties, especially the volume stability, of two types of BOF slags and andesite were first studied. Then, mechanical properties, volume stability, and an environment analysis are used to evaluate the application of pyrolytic BOF slag in cement-stabilized macadam. The experimental results show that different types of BOF slags have similar thermal expansion coefficients, which are higher than andesite. The free CaO content of pyrolytic BOF slag is much lower than that of ordinary BOF slag and the volume expansion of pyrolytic BOF slag is less than 0.5%. The unconfined compressive strength (UCS) of cement-stabilized macadam using pyrolytic BOF slag is about 30% higher than that of andesite. Although the water loss rate is higher than a natural aggregate, dry shrinkage of pyrolytic BOF slag cement-stabilized macadam is about 30–50% less than that of a natural aggregate. Meanwhile, its shrinking speed is also slower than that of a natural aggregate. The micro-expansion properties of pyrolytic BOF slag could effectively partially offset the shrinkage characteristics of cement-stabilized macadam. Finally, the Toxicity Characteristic Leaching Procedure (TCLP) test results indicated that the metal leaching concentration meets the Chinese environmental standards. This study provides a direction for the large-scale and effective sustainable application of pyrolytic BOF slag.