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1
Žibret, Lea, Katarina Šter, Maruša Borštnar, Mojca Loncnar e Sabina Dolenec. "The Incorporation of Steel Slag into Belite-Sulfoaluminate Cement Clinkers". Applied Sciences 11, n. 4 (19 febbraio 2021): 1840. http://dx.doi.org/10.3390/app11041840.
Testo completoAbstract (sommario):
The potential use of steel slag from treated steel slag in belite-sulfoaluminate cements was investigated in this study. Cement clinkers with two phase compositions were synthesized, allowing the incorporation of different amounts of steel slag. The phase composition and microstructure of cement clinkers at three different sintering temperatures were studied by X-ray powder diffraction and the Rietveld method, as well as scanning electron microscopy with energy dispersive spectrometry. The results showed that the targeted phase composition of clinkers was achieved at a sintering temperature of 1250 °C. However, a higher amount of perovskite instead of ferrite was detected in the clinker with a higher content of Ti-bearing bauxite. Apart from the main phases, such as belite, calcium sulfoaluminate, and ferrite, several minor phases were identified, including mayenite, perovskite, periclase, and alkali sulfates. In both clinker mixtures, a higher content of MgO in the steel slags resulted in the formation of periclase. Furthermore, the hydration kinetics and compressive strength at 7 and 28 days were studied in two cements prepared from clinkers sintered at 1250 °C. As evidenced by the results of isothermal calorimetry, the hydration kinetics were also influenced by the minor clinker phases. Cement with a higher content of calcium sulfoaluminate phase developed a higher compressive strength.
2
Enríquez, M. K., J. I. Tobón e J. H. Ramírez. "Use of industrial wastes for the synthesis of belite clinker". Materiales de Construcción 70, n. 339 (26 giugno 2020): 226. http://dx.doi.org/10.3989/mc.2020.14219.
Testo completoAbstract (sommario):
The synthesis of belite clinker was studied using industrial wastes: paper sludge, cement kiln dust and rice husk ashes, as substitutes for natural raw materials. Wastes were characterized by XRF, XRD and TG analysis. Different formulations were prepared to produce clinker at 1300, 1350 and 1400 °C. The clinker obtained was characterized using optical microscopy, XRD and f-CaO content determined by ethylene glycol method. Finally, the hydration of prepared cements with the clinkers was evaluated by isothermal microcalorimetry. It was found that by mixing paper sludge, cement kiln dust and rice husk ashes, it is possible to obtain belite clinker with f-CaO content below 0.5%, in clinkering temperatures between 1350 °C and 1400 °C without the use of natural raw materials. It was found that these cements have a high hydration kinetic, far above the rate of Ordinary Portland Cement, due mainly by the amorphous phase content in clinkers obtained.
3
Taimasov, B. T., B. K. Sarsenbayev, T. M. Khudyakova, A. S. Kolesnikov e N. N. Zhanikulov. "Development and Testing of Low-Energy-Intensive Technology of Receiving Sulphate-Resistant and Road Portlandcement". Eurasian Chemico-Technological Journal 19, n. 4 (29 dicembre 2017): 347. http://dx.doi.org/10.18321/ectj683.
Testo completoAbstract (sommario):
The article presents the obtaining results of clinkers of sulfate resistant and road cement during the production tests process. The usage of man-made wastes such as lead slag, coal mining waste as well as clay component and additives. X-ray, chemical analyzes of starting materials, clinkers and obtained cements were carried out. The regularities of charge compositions, saturation coefficient, modules, burning regimes on chemical and mineralogical composition and quality of clinkers and cements, improvement of rotary kiln operation, reduction of greenhouse gas emissions and fuel consumption are established. Various methods of analysis were used, calculations of raw mixtures composition were carried out according to the program "Shikhta" (designed to calculate the raw mix and the mineralogical composition of the clinker for the production of Portland cement. The program was developed in the V.G. Shukhov Belgorod State Technical University, Russia) and "Calculation of raw mixtures or CRM" (designed to calculate the raw mix of clinker. The program was developed in the M. Auezov South-Kazakhstan State University, Kazakhstan). The strength of factory and experimental cements was tested after 3, 7 and 28 days and after steaming.
4
Shen, Yan, Xi Chen, Jiang Li, Peifang Wang e Jueshi Qian. "Preparation and Performance of Ternesite–Ye’elimite Cement". Materials 15, n. 12 (20 giugno 2022): 4369. http://dx.doi.org/10.3390/ma15124369.
Testo completoAbstract (sommario):
Ternesite–ye’elimite (TCSA) cement is a new type of environmentally advantageous binder prepared by introducing ternesite, a reactive phase, into belite calcium sulfoaluminate cement clinker. This paper reports the laboratory production of TCSA cement by the addition of minor elements to achieve the coexistence of ternesite and ye’elimite. The influence of dopants on the mineralogical composition of clinkers and the clinkering conditions for the preparation of TCSA cement clinkers were investigated by X-ray powder diffraction and scanning electron microscopy. The mechanical properties and hydration products of the cement pastes were also studied. The results indicated that the addition of CaF2, P2O5 and Na2O can promote the coexistence of ternesite and ye’elimite, and that Na2O is the most effective candidate. TCSA cement clinkers could be successfully prepared at 1150 °C for 30 min by doping 0.3% Na2O. The TCSA cement clinkers exhibited shorter setting times than the BCSA cement clinkers. The later strength of TCSA cement showed a significant increase compared with BCSA cement. The effect of Na2O was different on the strength development for TCSA and BCSA cement. The dissolution of ternesite could promote the formation of ettringite. The reactivity of belite was higher in TCSA cement due to the formation of strätlingite.
5
Bădănoiu, Alina, Adriana Moanță, Ovidiu Dumitrescu, Adrian Ionuț Nicoară e Roxana Trușcă. "Waste Glass Valorization as Raw Material in the Production of Portland Clinker and Cement". Materials 15, n. 20 (21 ottobre 2022): 7403. http://dx.doi.org/10.3390/ma15207403.
Testo completoAbstract (sommario):
The paper presents experimental results regarding the synthesis of Portland clinker starting from raw mixes based on two types of clayey precursors, i.e., clay and marl (the most common types of raw materials used in the cement industry), with and without glass waste content. The soda-lime glass waste addition (5.36–5.59 wt %), used to control the silica ratio of the raw mix, improved the raw mix burnability and decreased the calcination temperature (by 20 °C), leading to a decrease in fuel consumption and contributing to the reduction in CO2 emissions associated with clinker and cement production. The clinkers obtained by the calcination of raw mixes with glass waste content at 1430 °C with a 30 min plateau had a similar mineralogical composition and microstructure to the clinkers obtained from the reference raw mixes and fulfilled the requirements of the specific standard EN 197-1. The obtained clinkers were used to produce two types of Portland cement, i.e., a unitary cement (CEM I) and a binary blended cement with slag (CEM II/B-S). The main characteristics of these cements, i.e., loss on ignition, insoluble residue, sulfate and chloride contents, as well as the setting time and soundness, meet the conditions stipulated in the EN 197-1 standard. The values of compressive strength, assessed on mortars after 2, 7 and 28 days of curing, allow the classification of all CEM I cements in the 42.5 R class. In the case of CEM II/B-S cements, those obtained from raw mixes with clay can be classified in the 42.5 N class, while those obtained from raw mixes with marl are classified in the 32.5 R class.
6
Samchenko, Svetlana, e Dmitriy Zorin. "Electricity costs for grinding of cement with expanding additives". International Journal of Engineering & Technology 7, n. 2.23 (20 aprile 2018): 274. http://dx.doi.org/10.14419/ijet.v7i2.23.11930.
Testo completoAbstract (sommario):
The most popular building material, including on transport facilities, is cement. Cement production is associated with the electricity costs. The biggest cost item is the consumption for the cement clinker grinding. It is known that disperse characteristics of cements, such as fineness of grinding, specific surface, coarseness of grading, largely determine their hydraulic properties, and for expanding cements - the deformation ones. In the paper, the issues of electric power consumption were considered when grinding extender expanders: aluminous slag, sulfoaluminate, sulfoferrite and sulfoalumoferrite clinkers.
7
Dolenec, Sabina, Katarina Šter, Maruša Borštnar, Klara Nagode, Andrej Ipavec e Lea Žibret. "Effect of the Cooling Regime on the Mineralogy and Reactivity of Belite-Sulfoaluminate Clinkers". Minerals 10, n. 10 (15 ottobre 2020): 910. http://dx.doi.org/10.3390/min10100910.
Testo completoAbstract (sommario):
This study investigated the influence of different cooling regimes on the microstructure and consequent reactivity of belite-sulfoaluminate clinkers. The cement clinkers were synthesized by incorporating secondary raw materials, such as titanogypsum and bottom ash, to the natural raw materials. Clinker phases were determined by Rietveld quantitative phase analysis, while the distribution morphology and the incorporation of substitute ions in the phases were characterized by scanning electron microscopy using energy-dispersive X-ray spectroscopy (SEM/EDS). Clinker reactivity was studied using isothermal calorimetry and was additionally investigated through compressive strength, which was determined for the cement prepared from the synthesized clinkers. X-ray diffraction analysis showed that, as well as the three main phases (belite, calcium sulfoaluminate, and ferrite), the clinkers contained additional minor phases (mayenite, gehlenite, arkanite, periclase, and perovskite), the ratios of which varied according to the cooling regime utilized. Microscopic observations indicated that the cooling regime also influenced the crystal size and morphology of the main phases, which consequently affected clinker reactivity. Furthermore, a smaller amount of substitute elements was incorporated in the main phases when cooling was slowed. Results showed that, in comparison to clinkers cooled at slower rates, air quenched clinkers reacted faster and exhibited a higher compressive strength at 7 days.
8
Luo, Li, Yimin Zhang, Shenxu Bao e Tiejun Chen. "Utilization of Iron Ore Tailings as Raw Material for Portland Cement Clinker Production". Advances in Materials Science and Engineering 2016 (2016): 1–6. http://dx.doi.org/10.1155/2016/1596047.
Testo completoAbstract (sommario):
The cement industry has for some time been seeking alternative raw material for the Portland cement clinker production. The aim of this research was to investigate the possibility of utilizing iron ore tailings (IOT) to replace clay as alumina-silicate raw material for the production of Portland cement clinker. For this purpose, two kinds of clinkers were prepared: one was prepared by IOT; the other was prepared by clay as a reference. The reactivity and burnability of raw meal, mineralogical composition and physical properties of clinker, and hydration characteristic of cement were studied by burnability analysis, differential thermal analysis, X-ray diffraction, and hydration analysis. The results showed that the raw meal containing IOT had higher reactivity and burnability than the raw meal containing clay, and the use of IOT did not affect the formation of characteristic mineralogical phases of Portland cement clinker. Furthermore, the physical and mechanical performance of two cement clinkers were similar. In addition, the use of IOT was found to improve the grindability of clinker and lower the hydration heat of Portland cement. These findings suggest that IOT can replace the clay as alumina-silicate raw material for the preparation of Portland cement clinker.
9
Orazimbetova, Gulistan, Umid Turdialiev e Laura Biniyazova. "Composition of raw mixes for portland cement clinkers using andesic basalt rock". E3S Web of Conferences 452 (2023): 06001. http://dx.doi.org/10.1051/e3sconf/202345206001.
Testo completoAbstract (sommario):
This article studies, calculation of compositions of raw mixes and development of clinker production technology on the basis of using local raw materials of Karakalpakstan, is an effective solution to the problem of covering the needs of the construction industry of the autonomous republic in cement. As well as component composition of raw mixes with different values of saturation coefficient (SC), silicate (n) and alumina (p) modules, calculated chemical and mineralogical composition of clinker on the base of new raw mixes. Some properties of clinkers and Portland cements based on them have been studied. Keywords: limestone, andesibasalt, brown ironstone, barchan sand, raw mixes, firing, clinker, general construction, sulphate-resistant, Portland cement
10
León-Reina, L., A. G. De la Torre, J. M. Porras-Vázquez, M. Cruz, L. M. Ordonez, X. Alcobé, F. Gispert-Guirado et al. "Round robin on Rietveld quantitative phase analysis of Portland cements". Journal of Applied Crystallography 42, n. 5 (8 settembre 2009): 906–16. http://dx.doi.org/10.1107/s0021889809028374.
Testo completoAbstract (sommario):
Interlaboratory studies on the precision and accuracy of Rietveld quantitative phase analysis (R-QPA) of mixtures of crystalline phases have already been carried out. However, cement-related materials are samples of variable complexity, ranging from three phases in white Portland clinkers to more than eight phases in grey cements, that need to be specifically investigated. Here, the results are reported from a round robin on the R-QPA of cement-related materials from laboratories with experience in this type of analysis. The aim of the work was to evaluate the levels of precision and accuracy associated with Portland clinkers and cements. Two sets of samples have been investigated, artificial mixtures and commercial samples. Artificial mixtures were prepared by mixing (weighing) synthesized single-crystalline phases in the appropriate proportions: (i) white clinker (Ca3SiO5, Ca2SiO4and Ca3Al2O6) and (ii) grey cement (Ca3SiO5, Ca2SiO4, Ca3Al2O6, Ca4Al2Fe2O10, CaCO3and CaSO4·2H2O). These two samples were used to assess the accuracy and uncertainty of the procedure, as an expected mineralogical phase fraction, the `true mineralogical percentage', is available under the assumption of negligible non-diffracting contents. In order to assess the validity and limitations of the Rietveld-based approach for cement materials, three commercial samples were measured: (i) white Portland clinker, (ii) grey Portland clinker and (iii) a type-I grey Portland cement. The samples studied have been chosen in order to cover most of the different typologies of binders. Reproducibilities and general uncertainty values, with a level of confidence of 95%, are reported and discussed.
11
Zheng, Liya, Thomas P. Hills e Paul Fennell. "Phase evolution, characterisation, and performance of cement prepared in an oxy-fuel atmosphere". Faraday Discussions 192 (2016): 113–24. http://dx.doi.org/10.1039/c6fd00032k.
Testo completoAbstract (sommario):
Cement manufacture is one of the major contributors (7–10%) to global anthropogenic CO2 emissions. Carbon capture and storage (CCS) has been identified as a vital technology for decarbonising the sector. Oxy-fuel combustion, involving burning fuel in a mixture of recycled CO2 and pure O2 instead of air, makes CO2 capture much easier. Since it combines a theoretically lower energy penalty with an increase in production, it is attractive as a CCS technology in cement plants. However, it is necessary to demonstrate that changes in the clinkering atmosphere do not reduce the quality of the clinker produced. Clinkers were successfully produced in an oxy-fuel atmosphere using only pure oxides as raw materials as well as a mixture of oxides and clay. Then, CEM I cements were prepared by the addition of 5 wt% gypsum to the clinkers. Quantitative XRD and XRF were used to obtain the phase and elemental compositions of the clinkers. The particle size distribution and compressive strength of the cements at 3, 7, 14, and 28 days' ages were tested, and the effect of the particle size distribution on the compressive strength was investigated. Additionally, the compressive strength of the cements produced in oxy-fuel atmospheres was compared with those of the cement produced in air and commercially available CEMEX CEM I. The results show that good-quality cement can be successfully produced in an oxy-fuel atmosphere and it has similar phase and chemical compositions to CEM I. Additionally, it has a comparable compressive strength to the cement produced in air and to commercially available CEMEX CEM I.
12
Kramar, S., L. Žibret, E. Fidanchevska, V. Jovanov, B. Angjusheva e V. Ducman. "Use of fly ash and phosphogypsum for the synthesis of belite-sulfoaluminate clinker". Materiales de Construcción 69, n. 333 (8 febbraio 2019): 176. http://dx.doi.org/10.3989/mc.2019.11617.
Testo completoAbstract (sommario):
Fly ash and phosphogypsum were used as Naturally Occurring Radioactive Materials (NORM) by-products for the synthesis of belite-sulfoaluminate clinkers. The influence of raw mixture composition and firing temperature was investigated. Clinkers and cements were examined by X-ray powder diffraction and scanning electron microscopy with energy dispersive X-ray spectroscopy. The compressive strength of the cements was determined after 28 days. Clinker phases identified included ye’elimite, ß-phase of belite, ternesite and gehlenite, while the main hydration product of the cement pastes was ettringite. The results showed that belite-sulfoaluminate cements can be fabricated with a compressive strength of 45.9 N/mm2 by firing the raw mixture (70 wt.% marl, 10 wt.% bauxite and 20 wt.% phosphogypsum) at a temperature of 1320°C/1h.
13
Jovanovic, Natasa, Miroslav Komljenovic, Ljiljana Petrasinovic-Stojkanovic, Zvezdana Bascarevic, Violeta Bradic e Aleksandra Rosic. "Substitution of the clayey mineral component by lignite fly ash in portland cement clinker synthesis". Chemical Industry 60, n. 9-10 (2006): 253–58. http://dx.doi.org/10.2298/hemind0610253j.
Testo completoAbstract (sommario):
Fly ash from four power plants in Serbia (PP "Morava" - Svilajnac, PP "Kolubara" - Veliki Grijani, PP "Kostolac" - units B1 and B2 - Kostolac and PP "Nikola Tesla" - units A and B - Obrenovac) was utilized as the starting raw component for Portland cement clinker synthesis. Limestone and quartz sand from the "Holcim - Serbia, a.d." cement factory were the other two starting raw components. Based on the chemical composition of the raw components and from the projected cement moduli, the amounts of raw components in the raw mixtures were calculated. Six different raw mixtures were prepared - each one consisted of limestone, sand and different fly ash. A raw mixture from the industrial production of the "Holcim - Serbia, a.d." cement factory was used as the reference material. The prepared raw mixtures were sintered in a laboratory furnace at 1400?C. The chemical and mineralogical compositions of the synthesized clinkers were determined. The characteristics of clinkers, based on fly ash, were compared to the characteristics of the industrial Portland cement clinker from the "Holcim - Serbia, a.d." cement factory. The results of the investigation showed that fly ash from power plants in Serbia can be suitable for Portland cement clinker synthesis.
14
Li, Xiaodong, Bing Ma, Wenqian Ji, Shang Dou, Hao Zhou, Houhu Zhang, Jiaqing Wang, Yueyang Hu e Xiaodong Shen. "Impact of Lime Saturation Factor on Alite-Ye’Elimite Cement Synthesis and Hydration". Materials 17, n. 12 (20 giugno 2024): 3035. http://dx.doi.org/10.3390/ma17123035.
Testo completoAbstract (sommario):
Alite(C3S)-Ye’elimite(C4A3$) cement is a high cementitious material that incorporates a precise proportion of ye’elimite into the ordinary Portland cement. The synthesis and hydration behavior of Alite-Ye’elimite clinker with different lime saturation factors were investigated. The clinkers were synthesized using a secondary thermal treatment process, and their compositions were characterized. The hydrated pastes were analyzed for their hydration products, pore structure, mechanical strength, and microstructure. The clinkers and hydration products were characterized using XRD, TG-DSC, SEM, and MIP analysis. The results showed that the Alite-Ye’elimite cement clinker with a lime saturation factor (KH) of 0.93, prepared through secondary heat treatment, contained 64.88% C3S and 2.06% C4A3$. At this composition, the Alite-Ye’elimite cement clinker demonstrated the highest 28-day strength. The addition of SO3 to the clinkers decreased the content of tricalcium aluminate (C3A) and the ratio of Alite/Belite (C3S/C2S), resulting in a preference for belite formation. The pore structure of the hydrated pastes was also investigated, revealing a distribution of pore sizes ranging from 0.01 to 10 μm, with two peaks on each differential distribution curve corresponding to micron and sub-micron pores. The pore volume decreased from 0.22 ± 0.03 to 0.15 ± 0.18 cm3 g−1, and the main peak of pore distribution shifted towards smaller sizes with increasing hydration time.
15
Oproiu, Carmen, Georgeta Voicu, Adrian Ionut Nicoara e Alina Ioana Badanoiu. "The Influence of Partial Substitution of Raw Materials with Heavy Ash on the Main Properties of Portland Cements". Revista de Chimie 69, n. 4 (15 maggio 2018): 860–63. http://dx.doi.org/10.37358/rc.18.4.6216.
Testo completoAbstract (sommario):
The use of wastes in cement industry have impact both from economic and environmental point of views. Wastes can be used in clinker manufacture (to substitute raw materials or as alternative fuel) as well as supplementary cementitious materials in cement. This paper presents results regarding the use of heavy ash (bottom ash) as component of raw mix used for the clinker manufacture. Two types of cements were obtained by the milling of clinker produced with/without heavy ash (HA) as component of raw mix and gypsum (2%). The compressive strengths of these cements was assessed on plastic mortars (water:binder = 1:2 ratio and binder:aggregate = 1:3 ratio), cast in prismatic moulds (14x14x160 mm3), hardened different periods of time comprised between 1 to 28 days. The hydration and hardening processes which occur in the cementitious systems with/without waste content were assessed on pastes with water to binder ratio of 0.5, hardened for 1 up to 90 days. X-ray diffraction (XRD) and complex thermal analysis (DTA-TG) were used for pastes� characterization. The composition of clinker was assessed by XRD and microstructure by scanning electron microscopy (SEM). The results obtained in the framework of this research do not show any important difference between the clinkers� characteristics produced with alternative raw material (heavy ash) as compared with the ones produced with natural raw materials. Also, the properties of cements produced of these clinkers are similar.
16
Benmohamed, Mohamed, Rabah Alouani, Amel Jmayai, Abdesslem Ben Haj Amara e Hafsia Ben Rhaiem. "Morphological Analysis of White Cement Clinker Minerals: Discussion on the Crystallization-Related Defects". International Journal of Analytical Chemistry 2016 (2016): 1–10. http://dx.doi.org/10.1155/2016/1259094.
Testo completoAbstract (sommario):
The paper deals with a formation of artificial rock (clinker). Temperature plays the capital role in the manufacturing process. So, it is useful to analyze a poor clinker to identify the different phases and defects associated with their crystallization. X-ray fluorescence spectroscopy was used to determine the clinker’s chemical composition. The amounts of the mineralogical phases are measured by quantitative XRD analysis (Rietveld). Scanning electron microscopy (SEM) was used to characterize the main phases of white Portland cement clinker and the defects associated with the formation of clinker mineral elements. The results of a study which focused on the identification of white clinker minerals and defects detected in these noncomplying clinkers such as fluctuation of the amount of the main phases (alite (C3S) and belite (C2S)), excess of the free lime, occurrence of C3S polymorphs, and occurrence of moderately-crystallized structures are presented in this paper.
17
Hattaf, Rabii, Mohamed Benchikhi, Abdessamad Azzouzi, Rachida El Ouatib, Moussa Gomina, Azzeddine Samdi e Redouane Moussa. "Preparation of Cement Clinker from Geopolymer-Based Wastes". Materials 14, n. 21 (30 ottobre 2021): 6534. http://dx.doi.org/10.3390/ma14216534.
Testo completoAbstract (sommario):
In order to avoid potential environmental pollution from geopolymer-based material wastes, this work investigated the feasibility of using these materials as alternative raw materials in the preparation of cement clinker. The geopolymer binders and mortars were used as substitutes for natural mineral clays since they are rich in silica and alumina. Simulated geopolymer wastes were prepared by the activation of metakaolin or fly ash by an alkaline silicate solution. The cement-clinkers fired at 1450 °C for 1h were characterized by XRD, XRF, SEM-EDS, and a free lime (CaOf) content test. The anhydrous clinker mineral phases C3S (Ca3SiO5), C2S (Ca2SiO4), C3A (Ca3Al2O6), and C4AF (Ca4Al2Fe2O10) were well-crystallized in all investigated formulations. The free lime was lower than 1.3 wt% in all elaborated clinkers, which indicates a high degree of clinkerization. The results demonstrate that geopolymer binder and mortar materials are suitable substitutes for natural mineral clay incement clinker preparation.
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Hall, Christopher, e Karen L. Scrivener. "Oilwell Cement Clinkers". Advanced Cement Based Materials 7, n. 1 (gennaio 1998): 28–38. http://dx.doi.org/10.1016/s1065-7355(97)00035-7.
Testo completo
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Gartner, Ellis, e Tongbo Sui. "Alternative cement clinkers". Cement and Concrete Research 114 (dicembre 2018): 27–39. http://dx.doi.org/10.1016/j.cemconres.2017.02.002.
Testo completo
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Staněk, Theodor, e Petr Sulovský. "Mechanism of Immobilization of Toxic Elements in Special Binders". Advanced Materials Research 1124 (settembre 2015): 3–9. http://dx.doi.org/10.4028/www.scientific.net/amr.1124.3.
Testo completoAbstract (sommario):
The paper deals with development of cementitious binders that would be able to efficiently immobilize toxic elements contained in various types of wastes. The basic component of the proposed binders are clinkers with phosphorus incorporated into the structure of clinker silicates, mixtures of cement with ash containing hydroxylapatite and belite-rich clinkers activated with sulfate anions. The prepared binders were mixed with water doped with various toxic elements; after a defined period of cement stone hydration the test beams were subjected to long-term testing of leachability of individual toxic elements. The research methods involved besides leaching tests also optical and electron microscopy.
21
Batalha Vieira, Luara, Vito Francioso, Bruna Bueno Mariani, Carlos Moro, Josiane Dantas Viana Barbosa, Larissa da Silva Paes Cardoso, Cleber Marcos Ribeiro Dias e Mirian Velay-Lizancos. "Valorization of Marble Waste Powder as a Replacement for Limestone in Clinker Production: Technical, Environmental and Economic Evaluation". Sustainability 15, n. 18 (19 settembre 2023): 13902. http://dx.doi.org/10.3390/su151813902.
Testo completoAbstract (sommario):
This research combines technical, environmental, and economic aspects regarding the utilization of Bege Bahia marble waste (BB) in clinker production. Three different eco-friendly clinkers were produced, investigated, and compared with one that is commercially available. BB was used to replace 49.2%, 77%, and 80.3% of the limestone by total amount of clinker. Two clinkers were selected to produce cement pastes, and their impact on compressive strength at 28 days was examined. The results suggest that substituting limestone with BB does not adversely affect the compressive strength of cement paste. Moreover, employing 77% or 80.3% BB in clinker production does not significantly influence the alite and belite contents but slightly increases the tricalcium aluminate and ferrite phases while reducing the periclase content. A life cycle analysis was conducted to assess the effects of replacing limestone with marble waste. The results revealed a substantial decrease in abiotic depletion, leading to conservation of substantial natural resources. Consequently, the utilization of BB in clinker production makes a significant contribution to environmental preservation while providing an effective alternative to limestone. In addition, the resulting clinkers serve as useful repositories, providing a permanent and sustainable destination for waste that is currently deposited in landfills. Finally, the economic viability was also examined under various scenarios based on the distance between marble and cement plants. The results highlight the transport distance of marble waste as the primary determinant of economic feasibility in utilizing this residue as a limestone replacement.
22
Grebenyuk, A., D. Smal, A. Davidyuk e P. Ponomareva. "OBTAINING MIXED COMPOSITE CEMENTS BASED ON FERRITE CLINKER". Bulletin of Belgorod State Technological University named after. V. G. Shukhov 8, n. 1 (16 gennaio 2023): 89–101. http://dx.doi.org/10.34031/2071-7318-2022-8-1-89-101.
Testo completoAbstract (sommario):
The possibility of using ferritic clinker as a component of binders with special performance properties is considered. Such types of cements can solve the problems of providing the construction industry with high-strength, resistant to external aggressive effects and relatively cheap binders. However, the mechanism of hardening and curing of cement stone obtained by using ferritic clinkers is complicated and depends on a number of parameters.
It was found that the greatest thermal effect (more than 70%) during the hydration of the resulting ferritic clinker with the introduction of various additives (lime and gypsum stone) is achieved up to 4 hours from the moment the binder compositions are mixed by means of a calorimetric analysis carried out during the hydration of the developed special binder compositions. That corresponds to the course of the induction period of hydration of the used Portland cement, at the time of the occurrence of primary contacts between crystalline hydrates and sufficient mobility of the cement mass. In this time interval, the strength of the cement stone is not high enough and the produced iron-containing hydration products are able to fill the space of the cement matrix, making it more dense and less defective.
The formation of iron-containing crystalline hydrates from ferritic clinker can proceed in several stages: hydrolysis of dicalcium ferrite at the initial stage of the reaction and further interaction of its products with portlandite in the period from 7 to 14 days from the moment of mixing the binder compositions. The main crystalline hydrates formed from ferritic clinker are iron-bearing ettringite and hydrogarnet.
The study of the physical and mechanical characteristics of cement stone showed that the optimal content of ferritic clinker in the composition of the binder compositions is 5%. With a given quantity, the strength of the cement stone in compression and bending exceeds that of the control sample by 11.5%. The input of 15 and 30% ferritic clinkers into the composition of special binders reduces the strength characteristics by 15-20%.
23
Krivoborodov, Yury. "Cement quality in thermochemical clinker activation". E3S Web of Conferences 402 (2023): 07002. http://dx.doi.org/10.1051/e3sconf/202340207002.
Testo completoAbstract (sommario):
Improving the quality of cement while reducing the energy costs of its production is one of the most important tasks of the cement industry. Cement properties are determined by the hydration activity of clinker minerals. In turn, the activity of clinker minerals is determined by the degree of disorderliness of the crystal cell. The disorder of the crystal cell depends on the chemical composition of minerals, the type and concentration of modifying additives. It also depends on the modes of clinker synthesis, both during firing and cooling. An effective way of activating clinker minerals is intensive firing of the components of the raw mixture. This method can be carried out by thermal activation of calcium oxide, as well as by bilateral introduction in different zones of the rotary kiln of polycomponent waste of chemical and metallurgical industries The composition and morphology of the main mineral of Portland cement clinker, alite, have been studied by methods of physical and chemical analysis. It was found that the crystals being formed are characterized by a nonstoichiometric composition. Their rapid growth is accompanied by intensive introduction of impurity elements into the crystal cell of the mineral. The hydration activity of clinkers of conventional and intensive firing has been determined. An increase in the rate of hydration of intensive firing clinkers has been established, which leads to an increase in the strength characteristics of cement by 7-10 MPa.
24
Zhang, Jie, Zong Hui Zhou e Xin Cheng. "Formation Kinetics of Regenerated Cement Clinker Calcined by Using Wasted Recycling Concrete Powders as Raw Meals". Advanced Materials Research 1073-1076 (dicembre 2014): 1309–12. http://dx.doi.org/10.4028/www.scientific.net/amr.1073-1076.1309.
Testo completoAbstract (sommario):
Artificial aggregates with high strength and a similar mineral composition to Portland cement clinker are made up of industrial waste and limestone, which are prepared for recycling concrete. Regenerated cement clinker is fabricated by recycling concrete powder added with a small amount of correction raw materia. Through the Gentling equation computing and microstructure morphology observation, the apparent activation energy (Ea) of two kinds of regenerated cement clinkers are 199 kJ/mol and 333 kJ /mol respectively, which is lower than that of traditional cement clinker (518 kJ/mol). The reaction rate constant (k) of regenerated cement clinker are about 4.8108×10-5 s-1 and 2.5003×10-5 s-1 at 1350°C. At the process of calcination, the formation temperature of C3S and sintering temperature of regenerated cement clinker are lower than that of the traditional cement clinker.
25
Lima, Maria Margarida Rolim Augusto, L. F. C. Braz, Regina da Conceição Corredeira Monteiro e J. P. Veiga. "Effect of Phosphogypsum on the Clinkerization Temperature of Portland Cement Clincker". Materials Science Forum 730-732 (novembre 2012): 94–99. http://dx.doi.org/10.4028/www.scientific.net/msf.730-732.94.
Testo completoAbstract (sommario):
Phosphogypsum (PG) is a pollutant residue resulting from the production of phosphoric acid in the phosphated fertilizers industry. About 180 millions of tons of PG are generated worldwide per year, which originates storage problems because of the environmental restrictions and the high costs of storage spaces. Taking into account the mineralizer properties of PG it has been studied a way to valorize this residue as an alternative material in the production of Portland cement clinker. The PG and the raw-materials (limestone, marl, sand and iron oxide) were chemical, mineralogical and thermally characterized by X-ray fluorescence (XRF), X-ray diffraction (XRD) and differential thermal analysis and termogravimetric analysis (DTA/TGA). After milling, the phosphogypsum was mixed with the raw-materials in different amounts up to 10% weight. The raw mixtures were submitted to two types of firing schedules, heating up to 1500°C without any holding time or heating up to 1350°C and holding for 20 minutes. After firing, the clinkers were analyzed by optical microscopy, milled and characterized in terms of chemical and mineralogical compositions. The clinkers were used to produce cement mortar according to NP EN 196-1 standard. The resultant test specimens were mechanically tested at 2 and 28 days according to the same standard. The obtained results show a reduction of about 140°C in the clinkerization temperature, when a raw mixture with 5% phosphogypsum was used. Standard clinkers, without phosphogypsum addition, which were fired at 1500°C, originated test specimens with a compressive strength of 48.1MPa at 28 days. Test specimens produced with clinker containing 5% phosphogypsum present higher compressive strength values at 28 days, being 55.1MPa for clinkers produced at 1500°C, and 49.4 MPa for clinkers produced at 1350°C.
26
Staněk, Theodor, Martin Boháč e Petr Sulovský. "Chemical Activation of Dicalcium Silicate and its Use for Cement Production". Advanced Materials Research 1151 (marzo 2019): 17–21. http://dx.doi.org/10.4028/www.scientific.net/amr.1151.17.
Testo completoAbstract (sommario):
In this work, it was found out that dicalcium silicate doped with SO3 shows higher hydraulic activity compared to pure dicalcium silicate. This finding was used to prepare and optimize high-belite cement from SO3 doped clinkers. The belite cement exhibited the same technological parameters, including short-term strengths, as ordinary Portland cement with a high content of tricalcium silicate. The clinker for belite cement is environmentally and economically advantageous. It is possible to burn the clinker at a temperature of 100 °C lower than conventional clinker and with lower consumption of calcium carbonate. In particular, methods of optical and electron microscopy were used for the research.
27
Wang, Lei, Run Dong Li, Yan Long Li e Li Hong Wei. "Incorporation of Cadmium into Clinker during the Co-Processing of Waste with Cement Kiln". Advanced Materials Research 347-353 (ottobre 2011): 2160–64. http://dx.doi.org/10.4028/www.scientific.net/amr.347-353.2160.
Testo completoAbstract (sommario):
The incorporation of cadmium into clinker during the co-processing of waste with cement kiln was investigated. Cadmium contained reagent was added to the cement raw meal to produce clinkers after clinkerization process. XRD analysis and SEM-EDS analysis were employed to indentify the major mineral phase of clinker and the cadmium contained mineral phase. Leaching test, sequential extraction procedures were employed to evaluate the leaching potential of cadmium in clinker. The results show the stabilization rate of cadmium during the clinkerization process is low. The incorporation ratio of cadmium in C2S is 0.32%~1.14%, the incorporation ability of cadmium in C2S is higher than C3S. The major mineral phases of clinker with the incorporation of cadmium were CH, C3S and C2S. The average leaching concentration of cadmium of clinker was 1.4 μg/L, which was higher than the blank samples. BCR Sequential extraction procedures analysis of the clinkers show exchangeable, water and acid-soluble fraction and residual fraction were very small, while the reducible phase of cadmium was up to 95.13%.
28
Storchai, N. S., e Yu L. Savin. "Use of ilmenite ore enrichment wastes in the production of Portland cement clinker". Voprosy Khimii i Khimicheskoi Tekhnologii, n. 5 (ottobre 2022): 110–14. http://dx.doi.org/10.32434/0321-4095-2022-144-5-110-114.
Testo completoAbstract (sommario):
We presented the results of the research on the influence of d-elements of ilmenite ore beneficiation wastes of the Vilnohirsk Mining and Metallurgical Plant on the structure and properties of Portland cement clinker minerals, firing properties and their hydraulic activity. It was established that the use of the enrichment wastes as an aluminosilicate component of the raw material mixture for clinker firing contributes to the reduction of the consumption of blast furnace granulated slag, simultaneously increasing the consumption of limestone. The presence of compounds of d-elements contained in the wastes of enrichment of ilmenite ore in the proposed raw material mixture for obtaining Portland cement clinker increases the saturation coefficient up to 99% and improves the processes of decarbonization and sintering during clinker firing. The physical-mechanical characteristics of the developed cements, in particular the compressive strength limit indicators, are not inferior to those produced according to the classical formulation. Cements obtained on the basis of clinkers, according to their properties, correspond to type II cements (state standard DSTU B.V. 2.7-46:2010). Partial replacement of the clay component in the raw material mixture by ilmenite ore enrichment wastes allows significantly expanding the raw material base for the production of Portland cement clinker and effectively influencing the technological process of firing.
29
Goswami, G., e J. D. Panda. "Application of XRD in a rapid quality control system of cement". Powder Diffraction 14, n. 2 (giugno 1999): 114–17. http://dx.doi.org/10.1017/s0885715600010393.
Testo completoAbstract (sommario):
The present paper establishes that the ratio between the XRD pulse counts of cement clinkers at d=0.278 and 0.274 nm bears a distinct relationship with the degree of sintering of the clinker, which is one of the factors that determine the cement quality. The paper also presents a rapid and accurate method for predicting both 3- and 28-day compressive strength (CCS) of cement mortar cubes based on XRD of the cement clinkers. The method is based on an index Xn derived from the XRD pulse counts at d=0.2959 and 0.287 nm corresponding to alite (hkl=202) and belite (hkl=102) phases of the clinker, respectively. The regression equation derived for a particular plant is (1) 3 day CCS=Xn×240 kg/cm2, when Xn<1 and 240+26 (Xn−1) kg/cm2, when Xn>1, where Xnmaximum=5.5. (2) 28 day CCS=C+C×In/100, where C=3 days CCS estimated by XRD (1), In=90−10Xn, where Xnmax=5.5. Calculated CCS values, in average, vary from the conventional test values by +5.9% to −5.4% and +3.8% to −3.5% in cases of 3- and 28-day CCS, respectively.
30
Venkatesh, Sivanandam, Kannan Ramkumar e Rengarajan Amirtharajan. "Predictive Controller Design for a Cement Ball Mill Grinding Process under Larger Heterogeneities in Clinker Using State-Space Models". Designs 4, n. 3 (15 settembre 2020): 36. http://dx.doi.org/10.3390/designs4030036.
Testo completoAbstract (sommario):
Chemical process industries are running under severe constraints, and it is essential to maintain the end-product quality under disturbances. Maintaining the product quality in the cement grinding process in the presence of clinker heterogeneity is a challenging task. The model predictive controller (MPC) poses a viable solution to handle the variability. This paper addresses the design of predictive controller for the cement grinding process using the state-space model and the implementation of this industrially prevalent predictive controller in a real-time cement plant simulator. The real-time simulator provides a realistic environment for testing the controllers. Both the designed state-space predictive controller (SSMPC) in this work and the generalised predictive controller (GPC) are tested in an industrially recognized real-time simulator ECS/CEMulator available at FLSmidthPvt. Ltd., Chennai, by introducing a grindability factor from 33 to 27 (the lower the grindability factor, the harder the clinker) to the clinkers. Both the predictive controllers can maintain product quality for the hardest clinkers, whereas the existing controller maintains the product quality only up to the grindability factor of 30.
31
., Marhaini, Eka Sri Yusmartini e Kurnia Aini. "The Effect of Tricalcium Silicate (C3S) Percentage in Clinkerson the Cement Quality". International Journal of Engineering & Technology 10, n. 1 (13 gennaio 2021): 23. http://dx.doi.org/10.14419/ijet.v10i1.31294.
Testo completoAbstract (sommario):
Composite cement products produced by national cement factories in Indonesia should follow the required quality standards. The quality standard of composite cement refers to the SNI 7064:2014. Some physical parameters of the quality standards set are mortar compressive strength and autoclave expansion. Compressive strength is influenced by C3S and C2S in the clinker. The reaction of the formation of mineralogical compounds occurs when clinkers formed. Whereas the expansion by autoclave is influenced by the levels of free lime in the cement. This research was conducted to determine the effect of the percentage of tricalcium silicate (C3S) on the quality of cement with free lime <2% and free lime > 2% with variations of C3S in clinkers, namely 55%, 57%, 59%, 61%, 63%, 65%, and 67%. Physical parameters tested in this study are compressive strength of mortar, blaine, and autoclave expansion. While the chemical parameters tested in this study are free lime in cement and SO3. Based on the research, it was found that if the same percentage of C3S quality of cement having FCaO <2%, the initial compressive strength results were greater than FCaO> 2%, the ideal condition of the development of compressive strength for FcaO > 2%, 3 to 7 days was at the percentage of C3S clinker of 63,48%. Whereas the development of ideal compressive strength for 7 to 28 days is at the clinker C3S percentage of 64,85%. For FCaO <2% the ideal condition 3 days to 7 days is at the percentage of clinker C3S of 62,79% and the development of compressive strength 7 to 28 days is at the percentage of clinker C3S of 54.77%. The expansion with autoclave experiencing expansion that does not meet the minimum requirements of SNI 7064:2014 are samples with a percentage of C3S 54,86% and 61% with FCaO > 2%.
32
Evdokimova, M. E., e M. A. Pashkevich. "Utilisation of titanium-containing wastes in the cement industry: A literature review". Vestnik MGTU 27, n. 2 (28 giugno 2024): 170–83. http://dx.doi.org/10.21443/1560-9278-2024-27-2-170-183.
Testo completoAbstract (sommario):
The metallurgical industry is among the leaders in waste production which has a high potential for recycling. The review paper considers the problems of metallurgical industry waste management and some possible ways of their solution. Waste acidic pickling solutions of titanium (titanium sludge) can be used as an additive to cement clinkers both to improve the characteristics of building materials and the efficiency of their production process. The influence of calcium fluoride (CaF2) and titanium dioxide (TiO2) on cement clinkers at different concentrations of substances and sintering temperatures has been reviewed. The data on changes in the content of free lime (f-CaO), patterns of formation and distribution of clinker phases: alite, belite, celite and calcium aluminiferite have been presented. Mechanisms of CaF2 and TiO2 inclusion in the composition of various cement phases have been explained. The conclusion has been made that the application of titanium-containing wastes allows not only to recycle them, but also to obtain construction materials with improved characteristics.
33
Mohapatra, B. N. "Effect of Bogue Potential Phases of Clinker on the Mechanical Strength of Fly ash-Limestone Based Portland Composite Cement". April 2021 2, n. 2 (12 dicembre 2021): 1–6. http://dx.doi.org/10.36937/cebacom.2021.5538.
Testo completoAbstract (sommario):
Continuous rise in population coupled with infrastructural requirements leads to increasing demand of cement which is projected to be around 4.8 billion tons by 2030 and 6.0 billion tons annually by 2050 from current production level of more than 4.2 billion tons [1], and this further requires judicious use of natural resources, particularly limestone on one side and to mitigate carbon and energy footprints on other for sustainable development. Therefore, to bring down environmental impact during cement production, cement industries have been engaged over the years to substitute Portland cement with alternative cementitious materials; fly ash, granulated blast furnace slag, limestone etc individually or in combination of two-three mineral constituents in the manufacture of blended cements, which showed better durability characteristics in comparison to ordinary Portland cement. The formulation and commercialisation of these cements largely depends on the quality of Portland clinkers in terms of oxide constituents, potential as well as actual phase composition, morphology and granulometry of alite and belite grains, along with availability and quality of the cementing materials, prevalent standard norms and regulations. In view of above, present paper highlights the effect of different clinkers in terms of potential minerals as per Bogue calculations (CL-1:C3S-48.20%, C3A-6.30%; CL-2:C3S-54.20%, C3A-9.30% and CL-3: C3S-60.05%, C3A-9.0%) on mechanical strength of fly ash-limestone based ternary cement blends, Portland composite cements, similar to CEM-II/A, B-M as per EN-197-1, prepared with 15, 20, 25, 30 and 35% by weight fly ash and 5 & 10% by weight limestone, by inter-grinding of all cement constituents process, maintaining Blaine’s fineness at 370±10m2/kg, and the results of compressive strength at different curing ages showed optimum strength development in case of clinker CL-2 with potential phases, C3S-54.20% and C3A-9.30%, thus leading to better management of natural resources and extended mine life.
34
Durczak, Karol, Michał Pyzalski, Tomasz Brylewski e Agnieszka Sujak. "Effect of Variable Synthesis Conditions on the Formation of Ye’elimite-Aluminate-Calcium (YAC) Cement and Its Hydration in the Presence of Portland Cement (OPC) and Several Accessory Additives". Materials 16, n. 17 (3 settembre 2023): 6052. http://dx.doi.org/10.3390/ma16176052.
Testo completoAbstract (sommario):
In the presented study, ye’elimite-aluminate-calcium (YAC) cement was synthesized. Complete synthesis of crystalline phases was achieved at a temperature of 1300 °C, which is 150 °C lower than the temperature standardly used in the processes of obtaining calcium aluminate cements (CAC). The greatest amount of ye’elimite phase (Klein complex), roughly 87% by mass, was acquired utilizing a sulphur ion transporter derived from artificial dihydrate gypsum obtained in the flue gas desulphurization process (variation I). In the case of anhydrite, the amount of synthesized crystalline ye’elimite in the clinker was 67% by weight (variant II). Depending on the synthesis conditions in the clinkers, the quantity of obtained calcium aluminates (C12A7, CA, and CA2) ranged from 20 to 40% by weight. Studies on the hydration process of YAC cement samples showed that the main products are hydrated calcium aluminates and dodecahydrate calcium alumino-sulphate. In sinters of YAC and OPC, no crystalline ettringite was observed. Hydration analysis of Chinese cement revealed the presence of crystalline ettringite and dodecahydrate calcium alumino-sulphate, as well as hydrated calcium silicates of the CSH type accompanied with pseudo-crystalline Al(OH)3. The obtained clinkers from variants I and II constitute a special binder, which, due to its phase composition after hydration, can be used in the construction of reactors for biogas production in eco-energy applications.
35
Fidanchevski, Emilija, Katarina Šter, Maruša Mrak, Ljiljana Kljajević, Gorazd Žibret, Klemen Teran, Bojan Poletanovic, Monika Fidanchevska, Sabina Dolenec e Ildiko Merta. "The Valorisation of Selected Quarry and Mine Waste for Sustainable Cement Production within the Concept of Circular Economy". Sustainability 14, n. 11 (2 giugno 2022): 6833. http://dx.doi.org/10.3390/su14116833.
Testo completoAbstract (sommario):
The cement industry could potentially consume large amounts of solid industrial waste in order to improve its sustainability. The suitability of selected quarry and mine waste as secondary raw materials (SRM) was examined for the sustainable production of cement following the concept of a circular economy. The chemical, mineralogical, and radiological characterization of SRM was conducted in this study. Its potential use in low-carbon and low-energy belite-sulfoaluminate cement was investigated by incorporating the examined SRM into cement clinker. Various characterization methods were used to characterize the cement, including X-ray powder diffraction (XRD), thermal analysis (DTA/TG), and isothermal calorimetry. Depending on the chemical composition of the waste, lower or higher amounts were allowed to be incorporated into the raw clinker mixture for a targeted clinker phase composition. Among the samples, differences were observed in the phase composition of synthesized clinkers, which slightly influenced the reactivity of the cement but did not significantly change the compressive strength of the final product.
36
Magrla, Radek, Karel Kulísek, Karel Dvořák e Dominik Gazdič. "Substitution of Limestone in Raw Mixture for Burning Portland Cement by FBC Ash". Advanced Materials Research 1124 (settembre 2015): 31–36. http://dx.doi.org/10.4028/www.scientific.net/amr.1124.31.
Testo completoAbstract (sommario):
This paper describes effort to reduce amount of gypsum in raw mixture for burning of Portland cement. Substitution of this material was realized by FBC ash. From these modified raw mixtures the clinkers were burnt, which were milled into cement then. These cements were subjected to basic technological tests.
37
Kabulova, Lola, e Gulistan Orazimbetova. "Research of Frost Resistance of Tuff-Containing Portland Cement". E3S Web of Conferences 491 (2024): 02003. http://dx.doi.org/10.1051/e3sconf/202449102003.
Testo completoAbstract (sommario):
Results of a study of frost resistance up to 150 cycles of freezing and thawing of Portland cement and pozzolanic Portland cements obtained on the basis of these Portland cement clinkers with various dosages burnt tuffite, gliège , showed that up to 30% tuffite to Portland cements with different mineralogical composition has a positive effect, increasing their grade in standard samples.
38
Zhao, Shi Zhen, Feng Lan Han, Gui Qun Liu, Mao Hui Li e Yu Jie Chen. "Preparation and Mechanical Performance of Sulpoaluminate Cement by Using Industrial Solid Wastes". Key Engineering Materials 726 (gennaio 2017): 510–14. http://dx.doi.org/10.4028/www.scientific.net/kem.726.510.
Testo completoAbstract (sommario):
By using Mn slag, Mg slag and Fly ash which comes from industrial process in Ningxia province as raw materials, the sulpoaluminate cement was prepared via sintering raw materials in a furnace. The physical and chemical characteristic of sulpoaluminate cement clinker was tested. The optimal proportion of clinkers is also determined by the results of phase composition, microstructure and hydration mechanism. The results shows that when the mixed ratio of Mn slag, Mg slag and Fly ash is 21%, 21% and 0% respectively in the raw materials and the calcination temperature is 1300 °C for 30 min, sulphoaluminate cement clinker with maximum amount of C4A3S, C2S and C4AF was prepared. Then, natural gypsum was added into the clinker powder with a ratio of 15% to make cement materials. When water to cement ratio is 0.5 and cement to sand ratio is 1:3, the cement mortar obtain a compressive strength of 22.22 MPa at 3d, 31.2 MPa at 7 d, and the flexural strength of 3.86MPa at 3d, and 4.83 MPa at 7d respectively.
39
Su, Dunlei, Gongbing Yue, Qiuyi Li, Yuanxin Guo, Song Gao e Liang Wang. "Research on the Preparation and Properties of High Belite Sulphoaluminate Cement (HBSAC) Based on Various Industrial Solid Wastes". Materials 12, n. 9 (9 maggio 2019): 1510. http://dx.doi.org/10.3390/ma12091510.
Testo completoAbstract (sommario):
In this study, a variety of industrial solid wastes, including petroleum coke desulfurization slag, fly ash and carbide slag with natural resource bauxite, were used as raw materials to prepare high belite suphoaluminate cement, which contains a certain CaSO4 content without adding natural gypsum to the clinker. The sintering temperature, mineral composition, and the physical and mechanical properties of the cement clinkers were investigated. The techniques adopted included a comprehensive thermal analysis (DSC-TG), X-ray diffraction (XRD), X-ray fluorescence (XRF) and scanning electron microscopy (SEM). The results revealed that it is completely feasible to prepare high belite sulphoaluminate cement with the various industrial solid wastes mentioned above and the utilization rate of the solid wastes is up to 80%. The sintering temperature ranges from 1225 °C to 1350 °C, and the optimal sintering temperature is approximately 1300 °C. The clinkers prepared at 1300 °C set and harden quickly and have a slightly higher water requirement of normal consistency. The mechanical strength is greatly affected by the CaSO4 and 3CaO·3Al2O3·CaSO4 contents and the most reasonable CaSO4 content is 15%.
40
Odler, I., e H. Zhang. "Investigations on high SO3 portland clinkers and cements I. Clinker synthesis and cement preparation". Cement and Concrete Research 26, n. 9 (settembre 1996): 1307–13. http://dx.doi.org/10.1016/0008-8846(96)00128-7.
Testo completo
41
Andrade, F. R. D., M. Pecchio, D. P. Bendoraitis, T. J. Montanheiro e Y. Kihara. "Basalt mine-tailings as raw-materials for Portland clinker". Cerâmica 56, n. 337 (marzo 2010): 39–43. http://dx.doi.org/10.1590/s0366-69132010000100007.
Testo completoAbstract (sommario):
Large volumes of waste materials are produced by crushing of basaltic rocks for aggregate production, which is widely used in regions that lack rocks of granitic or gneissic composition. Two types of waste materials are produced (a) quarry fines, which are in part used as fine aggregates in concrete and (b) vesicular basalt, a porous variety of basalt that is useless as aggregate. This paper presents a procedure to use basaltic mine-tailings as raw-mixtures for Portland cement by adjusting the proportion of the other raw-materials (limestone, clay, iron ore). It is demonstrated that there is no need for additional fluxes to the basalt-bearing raw-mixtures, since the setting of the chemical parameters is enough to guarantee clinker formation. Two series of experimental clinkers were synthesized with raw-mixtures containing residues from a basalt quarry that produces aggregates for concrete. Experimental clinkers were produced from raw-mixtures with similar lime saturation factors, silica and alumina modules, which were set by adjusting the proportions of limestone, clay and iron ore to the varying proportions of basaltic materials added to them. One series of clinkers was made with basalt quarry fines, which are in part used as fine aggregate, but also accumulate as mine-tailings. Other series was made using vesicular (porous) basalt, a variety not resistant enough to be used as aggregate. It is demonstrated that the basaltic composition is fully compatible with clinker production, and no addition of fluxes or other additions is required. Composition of the raw-mixtures was checked by chemical analysis. Quantitative phase analysis of the clinkers was made by optical microscopy point counting, together with qualitative X-ray diffraction. All mixtures produced clinkers with acceptable proportions of major and minor crystalline phases, inside the range of common industrial Portland clinkers.
42
Wu, Yuan Chao, Xiao Cun Liu, Bao Liang Li, Tong Liu, Wei Shan Wang e Yan Jun Li. "Study on the Adaptability Between the Amount of C3S Mineral in Alite-Sulphoaluminate Cement Clinker and the Fly Ash". Advanced Materials Research 306-307 (agosto 2011): 975–79. http://dx.doi.org/10.4028/www.scientific.net/amr.306-307.975.
Testo completoAbstract (sommario):
The paper studied the adaptability between alite-sulphoaluminate cement clinkers with different amount of C3S and the fly ash admixture. The results showed that: with a fixed content of C3S, the setting time of the cement delayed, and the compressive strength of the cement decreased with increasing amount of fly ash admixture. With a fixed content of the fly ash admixture, the setting time of the cement delayed, the compressive strength of the cement increased with the increase amount of C3S, and the lowed percentage of the strength decrease at each ages; With addition of fly ash admixture, the early compressive strength of the cement decreased more, while the later compressive strength decreased less. Clinker with higher C3S content showed better adaptability with high addition amount of fly ash admixture.
43
Pizoń, Jan, Beata Łaźniewska-Piekarczyk e Patrycja Miera. "The Influence of the Acceleration Admixture Type and Composition of Cement on Hydration Heat and Setting Time of Slag Blended Cement". Materials 15, n. 8 (11 aprile 2022): 2797. http://dx.doi.org/10.3390/ma15082797.
Testo completoAbstract (sommario):
This article presents recent research on cements containing GGBFS and their modifications with accelerating admixtures. The initial setting time and hydration heat evolution results are presented for cement CEM II/B-S and CEM III/A manufactured with three Portland clinkers of various phase compositions. The research was carried out at 8 °C and 20 °C. The main objective is to assess the behavior of blended cements in cooperation with modern admixtures that contain nucleation seeds. The authors aimed to compare and evaluate different methods to reduce setting time, namely, the effects of temperature, the specific surface area of cement and GGBFS, the type of Portland clinker, the content of GGBFS, and presence of accelerators. Many of these aspects appear in separate studies, and the authors wanted a more comprehensive coverage of the subject. Those methods of reducing the setting time can be ranked: the most effective is to increase the temperature of the ingredients and the surroundings, the second is to reduce the GGBFS content in cement, and the use of accelerators, and the least effective is the additional milling of Portland clinker. However, of these methods, only the use of accelerators is acceptable in terms of sustainability. Prospective research is a detailed study on the amounts of C-S-H phase and portlandite to determine the hydration rate.
44
da Silva Andrade Neto, José, Bruna Bueno Mariani, Nilson Santana Amorim Júnior e Daniel Véras Ribeiro. "Characterization of Cements Produced from Clinker Co-Processed with TiO2 Waste (UOW)". Key Engineering Materials 803 (maggio 2019): 278–83. http://dx.doi.org/10.4028/www.scientific.net/kem.803.278.
Testo completoAbstract (sommario):
The aim of the present study is to evaluate the properties of cements produced from clinkers co-processed with unreacted ore waste (UOW), that is a waste generated in TiO2 production. A commercial CP V ARI RS cement and four different cements produced in the laboratory were characterized. The cements produced in the laboratory were made from raw mixes with a Lime Saturation Factor (LSF) fixed in 98% and varying the incorporation content of TiO2 in 0% (reference); 0.5%; 1.0% and 2.0% from the incorporation of UOW, by weight. The raw mixes were calcined at 1340°C and the resulting clinkers were mixed and interground with gypsum, thus resulting in the laboratory cements. These cements were characterized physically and mineralogically, besides tests of loss on ignition, expansibility (Le Chatelier’s needle) and compressive strength at 1, 3, 7, 28 and 91 days. It was observed that the incorporation of the UOW enhanced the formation of alite, due to the mineralizing effect of the titanium, and cement with 0.5% TiO2 (1.3% of UOW) presented the highest strength.
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Liu, Yan Jun, e Yong Chao Zheng. "Mineral Waste Coupled with Boron Oxide for Producing Active Belite Cement Clinker". Applied Mechanics and Materials 405-408 (settembre 2013): 2564–75. http://dx.doi.org/10.4028/www.scientific.net/amm.405-408.2564.
Testo completoAbstract (sommario):
This paper presents a laboratory study on active belite cement clinker using boron oxide as dopant to stabilize high temperature phases of Dicalcium silicate (C2S), and mineral waste as siliceous materials in complete replacement of clay. The clinker samples were soaked in Muffle Furnace at different burning temperatures and for various time durations, and then, cooled down to room temperature using air blower. Quantitative X-ray Diffraction analysis (QXRD) by Rietveld method indicates that major mineral components are Dicalcium Silicate (C2S), Ferrite (C2 (A0.48F1.52) O5) and trace amount of Tricalcium Silicate (C3S) in the cement clinkers. Among them, Dicalcium silicate is over 85 percent, Ferrite around 10 percent and Tricalcium silicate less than 10 percent. Thermogravimetric and Differential Scanning Calorimetric (TGA-DSC) spectrum shows that there is no significant phase change while cement clinker was cooling down, which means significant amount of high temperature polymorphic C2S was stabilized during cooling process. It is agreeable with the results from QXRD analysis. Specifically, among polymorphic belite phases, αH-C2S accounts for around 66% of cement clinker, and αL-C2S for about 22% of cement clinker. In addition, massive belite phase was identified by Scanning Electronic Microscope (SEM) analysis and Light Microscopy analysis. At last, the mechanical tests on active belite cement show that active belite cement clinker has a slow strength development at early ages, but rapid strength gain at 28 days in comparison with belite clinker without adding boron oxide. Thus, this active belite cement clinker demonstrates very promising prospect in sustainable cement industry development. Keywords: Active Belite Cement Clinker; Doped; Boron Oxide; αH-C2S; αL-C2S; Strength Development
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Kuandykova, Aknur, Bakhitzhan Taimasov, Ekaterina Potapova, Bakhitzhan Sarsenbaev, Alexandr Kolesnikov, Meiram Begentayev, Erzhan Kuldeyev et al. "Production of Composite Cement Clinker Based on Industrial Waste". Journal of Composites Science 8, n. 7 (3 luglio 2024): 257. http://dx.doi.org/10.3390/jcs8070257.
Testo completoAbstract (sommario):
The possibility of producing cement clinker using low-energy, resource-saving technologies is studied. The composition of industrial waste for low-energy-intensive production of Portland cement clinker at factories in Southern Kazakhstan is analyzed. The possibility of replacing the deficient iron-containing corrective additive with “Waelz clinker for zinc ores” is shown. “Waeltz clinker from zinc ores” as part of the raw material charge performs several tasks: it is a ferrous corrective additive, works as a mineralizer for clinker formation processes, introduces coal into the charge and allows one to reduce the consumption of natural fuel. The processes of burning raw mixtures, wholly or partially consisting of industrial waste, are completed at 1350 °C. This reduces the consumption of main burner fuel for clinker burning and reduces CO2 emissions into the atmosphere. High-quality cement clinker is obtained based on raw material mixtures with Waeltz clinker from zinc ores from the Achisai Metallurgical Plant, phosphorus slag, coal mining waste from Lenger mines and sodium fluoride. The phase composition and microstructure of low-energy clinkers are revealed. Involving industrial waste in raw material circulation will reduce environmental pollution and improve the environment.
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Yan, Man, Min Deng, Chen Wang e Zhiyang Chen. "Effect of Particle Size of Periclase on the Periclase Hydration and Expansion of Low-Heat Portland Cement Pastes". Advances in Materials Science and Engineering 2018 (9 ottobre 2018): 1–8. http://dx.doi.org/10.1155/2018/1307185.
Testo completoAbstract (sommario):
In this paper, low-heat Portland cement (LHC) clinkers were prepared by calcining raw materials at 1350°C for 2.0 hours, 1400°C for 1.0 hour, 1400°C for 1.5 hours, 1400°C for 2.0 hours, 1450°C for 1.0 hour, and 1450°C for 2.0 hours. The clinkers were ground with gypsum to produce LHC. The particle size of periclase was analysed by BSEM. Expansion of LHC pastes due to hydration of periclase was measured. The hydration degree of periclase in LHC pastes was quantitatively determined by XRD internal standard method and BSEM. The results showed that the particle size of periclase was larger when clinkers were calcined at higher temperatures or for longer time. Smaller periclase (2.60 μm) in LHC pastes tended to hydrate faster. As a result, expansion of LHC pastes develops relatively faster. Smaller particle of periclase in clinker tends to result in higher hydration degree of periclase in pastes cured at 20°C for 240 days, and there is a small amount of brucite appearing around periclase. The hydration rate of 4.00 μm periclase particle in cement paste cured at 80°C is obviously faster than that in paste cured at 20°C and 40°C. When cement paste was cured at 80°C for 7 days, the periclase was hydrated for 32.56%. The smaller size periclase (1–3 μm) had fully hydrated when the curing age was 240 days, and a large amount of brucite was produced around the larger periclase particle.
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Jiao, You Zhou, Pan Ding e Shuang Li Du. "Research on Mineral Formation Mechanism of Pulverized Coal Combustion Boiler Co-Generating Q-Phase Cement Clinker". Advanced Materials Research 512-515 (maggio 2012): 1687–91. http://dx.doi.org/10.4028/www.scientific.net/amr.512-515.1687.
Testo completoAbstract (sommario):
Conduct test of 2CaO•Al2O3•SiO2 transformed into Q-phase mineral with analytical reagent CaO, SiO2, Al2O3 and MgO in library high-temperature furnace. And carry out experimental investigation on the mineral formation rule of co-generation Q-phase cement clinker on two-section multiphase reaction test stand simulating pulverized coal combustion boiler based on the test. It was found that: 2CaO•Al2O3•SiO2 may generate Q-phase mineral with hydration activity together with appreciated amount of CaO and MgO; experimental coal sort in reasonable ratio may co-generate cement clinker with main mineral sort of 2CaO•SiO2 and Q-phase mineral. Thermodynamic analysis on mineral formation reaction shows that, in Yanzhou coal co-generating Q-phase cement clinker, the most probably occurring is the direct synthesis reaction of 2CaO•Al2O3•SiO2, followed by 2CaO•SiO2 direct synthesis reaction and the Q-phase indirect synthesis reaction comes last according to chemical composition of clinkers.
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Putri, Nilda Tri, e Indah Kurnia Ramadhani. "Penjadwalan Cement Mill Berbasis Minimasi Faktor Klinker dalam Proses Pembilasan dan Impor Klinker". Jurnal Optimasi Sistem Industri 15, n. 1 (1 aprile 2016): 62. http://dx.doi.org/10.25077/josi.v15.n1.p62-77.2016.
Testo completoAbstract (sommario):
PT Semen Padang is one of the cement companies in Indonesia. Cement production influenced by the number of demand, raw materials and the number of the available machine. The number of demand increases with a corporate capacity which keeps the company had to set an optimal production schedule. Scheduling production should be followed by the availability of raw materials (clinker). The number of clinkers required influenced by the number of demands and clinker elapsed to the flushing process. Flushing process happens if the transition products produced from Non-OPC to a product OPC, for one flushing process causes clinker consumption 7% more than the existing capacity decreases. Deficient in a capacity covered by importing clinker which causes high-cost production. So, it necessary to make cement mill schedule by minimizing flushing process, so clinker that will be used become optimized.Steps that will be done in this study began with the survey system, identify problems, and data collection. Data collected are machine cement mill and kiln capacity, demands, and flushing process. Then designed a formulation model that minimizes clinker factor and the number of clinker imports needed, so that obtained scheduling machine cement mill to produce OPC and Non-OPC.Results obtained by reducing the number of flushing process because the cement mill designed to produce one type of product per day, so the flushing process could happen if there is transition cement production Non-OPC on the day-i to cement OPC on the day i+1. Cement OPC produced by Indarung II, III, and V. Indarung IV only produced cement Non-OPC, so the flushing process happened in Indarung II, III, and V.
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Zhao, Pi Qi, Wen Zong, Shou De Wang, Gui Yun Wang e Ling Chao Lu. "Performance of Belite-Barium Calcium Sulphoaluminate Cement Prepared by Substituting Fly Ash for Clay". Advanced Materials Research 306-307 (agosto 2011): 1066–70. http://dx.doi.org/10.4028/www.scientific.net/amr.306-307.1066.
Testo completoAbstract (sommario):
The mineral structure and performance of belite-barium calcium sulphoaluminate cement clinkers were investigated by petrographic analysis, X-ray diffraction and scanning electron microscopy. The experimental results showed that the minerals of calcium barium sulphoaluminate (C2.75B1.25A3) and C2S could coexist in the belite-barium calcium sulphoaluminate cement clinker, and the optimal sintering temperature was 1380°C, at which, more C2.75B1.25A3was formed, well developed and also evenly distributed in the optimal sintering condition. If the sintering temperature exceeded 1380°C, the decomposition of C2.75B1.25A3 would speed up and the C3S became inactivate for its excessive development. In the optimal sintering condition, the compressive strength of the prepared cement at 3, 7, 28 d were 32.6, 47.9, 88.5 MPa respectively, which exhibited excellent mechanical properties.