Journal articles: 'Zone Refining Process'

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Yoon, Young Ok, Hyung Ho Jo, Hoon Cho, Shae K. Kim, and Young Jig Kim. "Effect of Distribution Coefficient on Copper Purification by Zone Refining Process." Materials Science Forum 449-452 (March 2004): 173–76. http://dx.doi.org/10.4028/www.scientific.net/msf.449-452.173.

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It has been generally known that the refining efficiency in zone refining process depends on travel rate, number of pass and distribution coefficient of impurity. In the present study, the effect of distribution coefficient on copper purification was investigated by zone refining process. A numerical model capable of predicting the solute redistribution at any stage of zone refining was proposed. The composition profiles of each segment at the given condition were compared with the results of micro hardness profiles. After zone refining, metallic elements were analyzed by GDOS (Glow Discharge Optical Spectroscopy) and GDMS (Glow Discharge Mass Spectrometry). The impurities Ag, Pb, S and Ti, whose distribution coefficients are below 0.5, were concentrated at the finishing position. Cr, Mn, Si and Zn, whose distribution coefficients are between 0.5 and 1, were distributed irregularly. Fe and Ni, whose distribution coefficients are greater than 1, moved to the starting position. It was found that zone refining process was actually effective to remove impurities whose distribution coefficients are below 0.5. The experimental results agreed well with the simulation result.

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Karlström, Anders, and Jan Hill. "Control strategies for refiners Part I: Soft sensors for CD-refiner control." Nordic Pulp & Paper Research Journal 33, no. 1 (May 23, 2018): 28–43. http://dx.doi.org/10.1515/npprj-2018-3007.

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Abstract Internal variables in (C)TMP-refining processes (e. g. temperature, consistency, fiber residence time, backward flowing steam and forces acting upon the chips and pulp) are defined as physical states obtained in different parts of the refining zones. In short, they differ from the traditional external variables (e. g. dilution water feed rate and specific energy) which are not obtained from measurements or physical models of the process in the refining zone. The internal variables are the backbone of physical models and are used in this paper as soft sensors for advanced process control. Besides the shape of the temperature profile, the position of the maximum temperature and the shape of the consistency profiles inside the refining zones are important to control as they are directly linked to the development of different pulp and handsheet properties. To illustrate the capability when using combined modeling and control strategies, the concept is applied on a full scale CD82 refiner. This means both temperature and consistency control in the flat zone and the conical zone, together with an overall estimator for fiber development. Finally, in this paper it is shown that the production can be increased significantly without changing the refiner motor load nor violating the pulp property specification.

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Karlström, Anders, and Karin Eriksson. "Fiber energy efficiency Part I: Extended entropy model." Nordic Pulp & Paper Research Journal 29, no. 2 (May 1, 2014): 322–31. http://dx.doi.org/10.3183/npprj-2014-29-02-p322-331.

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Abstract This is the first in a series of papers presenting the development of a comprehensive multiscale model with focus on fiber energy efficiency in thermo mechanical pulp processes. The fiber energy efficiency is related to the defibration and fibrillation work obtained when fibers and fiber bundles interact with the refining bars. The fiber energy efficiency differs from the total refining energy efficiency which includes the thermodynamical work as well. Extracting defibration and fibrillation work along the radius in the refining zone gives information valuable for fiber development studies.Models for this process must handle physical variables as well as machine specific parameters at different scales. To span the material and energy balances, spatial measurements from the refining zone must be available. In this paper, measurements of temperature profile and plate gaps from a full-scale CD-refiner are considered as model inputs together with a number of process variables. This enables the distributed consistency in the refining zone as well as the split of the total work between the flat zone and the CD-zone to be derived. As the temperature profile and the plate gap are available in the flat zone and the CD-zone at different process conditions it is also shown that the distributed pulp dynamic viscosity can be obtained. This is normally unknown in refining processes but certainly useful for all fluid dynamic models describing the bar-to-fiber interactions. Finally, it is shown that the inclusion of the machine parameters will be vital to get good estimates of the refining conditions and especially the split between the thermodynamical work and the defibration/fibrillation work.

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Ferritsius, Rita, Olof Ferritsius, Jan Hill, Anders Karlström, and Karin Eriksson. "TMP properties and refining conditions in a CD82 chip refiner. Part I: Step changes of process variables, description of the tests." Nordic Pulp & Paper Research Journal 33, no. 1 (May 23, 2018): 69–81. http://dx.doi.org/10.1515/npprj-2018-3002.

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Abstract The study explores how changes in process variables, residence time and pulp consistency in refining influence the pulp properties. The equipment utilized in this study was a conical disc chip refiner (RGP82CD) producing thermomechanical pulp (TMP). The focus was on the ratio between tensile index and specific energy consumption. Pulp properties were measured for composite pulp samples taken from the refiner blow line. Residence times and pulp consistencies were estimated by use of the extended entropy model. This showed that the CD-refiner, with the flat and conical refining zone, has a process performance similar to that of a two-stage refiner set-up, and that the consistency in both refining zones is of high importance. Comparing different periods revealed that even if the values of measured blow line consistency are similar, significant differences in the estimated consistency in the flat zone can prevail. Therefore, only monitoring blow line consistency is not enough. Specifically, it was found that the pulp consistency after the flat zone could be very high, considerably higher than in the blow line, and this could have negative effects on tensile index and fibre length.

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Zhang, Xiaoxin, Semiramis Friedrich, and Bernd Friedrich. "Characterization and Interpretation of the Aluminum Zone Refining through Infrared Thermographic Analysis." Materials 11, no. 10 (October 19, 2018): 2039. http://dx.doi.org/10.3390/ma11102039.

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High purity metals are nowadays increasingly in demand to serve in electronic, photovoltaic, and target materials industries. The zone refining process is the most common way to achieve high purity in the final step of metal purification. Zone length and crystal growth rate are the main parameters that control the zone refining process. To determine these values, information about temperature profiles in the molten zone is necessary due to its direct correlation with these values. As the determination of this profile is not practically achievable in the present, the novel approach of applying an infrared (IR) camera during the zone refining of 2N8 aluminum is the focus of the investigation in this work. The whole temperature profile of the region near the molten zone was recorded by IR camera during the entire running process. The zone length and the crystal growth rate at each thermographic image shooting moment were successfully extracted by thermographic analysis. Results showed that both factors varied significantly, which is in contrast to the assumption in literature about their stability while running under constant input power and heater movement velocity, though noticeable purification took place in all of these experiments. However, the impurity concentration during refinement fluctuated remarkably. This was well-demonstrated by the tendency of variation in crystal growth rate attained in this work. These results provide a better understanding of the mechanisms of zone refining with an inductive heater and contributes to the optimization of the process.

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Park, Hyeong-Hun, Chul-Hwan Kim, Ji-Su Lee, and Cheong-Ha Lee. "Effects of Refiner Plates with Different Fillings on TMP Properties." Applied Sciences 13, no. 8 (April 19, 2023): 5091. http://dx.doi.org/10.3390/app13085091.

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This study conducted a comparative analysis of two refiner plates that had different bar patterns. The plates were designed with three distinct zones, including the high-intensity zone, the transition zone, and the low-intensity zone, and had a draft angle of 4–5 degrees. The two refiner plates had a significant difference in cutting edge length (CEL) of approximately four times. Specifically, TMP plate A (TP A) had a CEL of 5.1 km/s, while plate B (TP B) had a CEL of 22.7 km/s, indicating that TP A applied greater force to the wood chips during refining. TP A exhibited greater stock throughput at the same refining energy compared to TP B due to its smaller CEL. The low-intensity refining of TP B promoted the fibrillation of TMP fibers, leading to a large decrease in fiber width without significantly changing the mean fiber length before and after refining. The bulk of TMP and CTMP increased slightly more in TP B than in TP A. However, TP A showed a greater decrease in tensile strength due to a larger decrease in fiber length, whereas there was no significant change in tear strength between the two plates.

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Li, Yang, Zhou Hua Jiang, Shi You Yin, Ying Zhuang, and Ming Li. "Effect of Refining Slag on the Inclusions of Hard Wire Steel during Melting Process." Advanced Materials Research 217-218 (March 2011): 1174–79. http://dx.doi.org/10.4028/www.scientific.net/amr.217-218.1174.

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The effect of the refining slag composition on the total oxygen content and inclusions in steel was investigated in 100 t UHP Electric Furnace – LF – Billet CC process. The test steel was 77B hard wire steel and Si-Mn alloy was used as the deoxidizer. Three types slag were used in the industrial tests, which including CaO-CaF2, CaO-CaF2 adding CaC and CaO-Al2O3 refining slag. The results shown that the lowest total oxygen contents of rolled bar can be gained using the CaO-CaF2 refining slag adding CaC, which is 0.0036%, while the total oxygen contents of rolled bar using CaO-Al2O3 refining slag is higher a little than the heats using CaO-CaF2 refining slag. The CaO-SiO2 and CaO-Al2O3-SiO2 compound inclusions with the size of about 5 μm are the main inclusions in the heats refining by the CaO-CaF2 refining slag in the rolled bar, but the pure, indeformable Al2O3 inclusion can also be found with the size of about 10 μm. The CaO-Al2O3-SiO2 and Al2O3-SiO2-MnO compound inclusions are the main inclusions in the heats refining by the CaO-CaF2-CaC refining slag, but most of the inclusion shape is irregular with bigger size of about 10 μm. Similar with the heat using CaO-CaF2 refining slag, the pure Al2O3 inclusion with edge angle can be found in the rolled bar. The inclusions in the rolled bar treated by CaO-Al2O3 refining slag are CaO-Al2O3-SiO2 compound inclusions, most of which are nearly globular shape with the relative small size of about 5 μm. All of the inclusions in rolled bar lie on the low melting zone in the CaO-Al2O3-SiO2 ternary phase diagram in the heats using CaO-Al2O3 refining slag. The similar condition appeared on the most of the inclusions in the heats using CaO-CaF2 and CaO-CaF2 refining slag adding CaC, while part of which are lied on the high melting zone. Therefore, considering of the plastic deformation ability, the CaO-Al2O3 refining slag is the best slag for the melting process of hard wire steel.

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Wen, Jiajun, Meizhen Wu, Jubo Peng, and Hongxing Zheng. "Purification of High-Purity Tin via Vertical Zone Refining." Separations 10, no. 7 (June 28, 2023): 380. http://dx.doi.org/10.3390/separations10070380.

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The present investigation delves into the potential of vertical zone refining as an effective purification technique for achieving high-purity tin (Sn) metal. The utilization of vertical zone refining offers distinct advantages over traditional horizontal zone refining, as it allows for enhanced control over the molten zone and solid–liquid interface, ultimately leading to superior impurity separation efficiency. The present study reveals that the solute partition coefficients (k0) of various impurity elements, such as Zn, Ag, Al, Mg, Ca, Ni, In, Co, Cu, As, Pb, Fe, and Bi, during the vertical zone refining process consistently demonstrate values below one. Notably, the partition coefficient of Sb deviates slightly from the others, being greater than one but approaching one. The authors achieve exceptional levels of purity in both the bottom and middle regions of the rod by subjecting the Sn melt to nine passes of vertical zone refining at a heating temperature of 405 °C and a downward pulling rate of 10 µm/s, resulting in purities exceeding 6N4. Furthermore, by evaluating the effective partition coefficients (keff), it was determined that impurity elements, such as Cu and Bi, closely approach their equilibrium partition coefficients, reaching values of approximately 0.492 and 0.327, respectively. To further enhance the purity of Sn metal and maximize product yield, we propose the utilization of electrolytic refining and vacuum distillation, with particular emphasis on the efficient separation of five specific elements, including Cu, Fe, As, Pb, and Sb. By elucidating these findings, this study not only contributes valuable insights into the efficacy of vertical zone refining as a purification technique for high-purity tin metal, but also offers important recommendations for refining strategies and impurity element separation.

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Karlström, Anders, and Karin Eriksson. "Fiber energy efficiency Part II: Forces acting on the refiner bars." Nordic Pulp & Paper Research Journal 29, no. 2 (May 1, 2014): 332–43. http://dx.doi.org/10.3183/npprj-2014-29-02-p332-343.

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Abstract In this paper it is shown that the defibration and fibrillation work in thermo mechanical pulp refiners can differ significantly dependent on the process conditions. This has a direct impact on the distributed force in the refining zones obtained when the bars hit the fibers or fiber bundles. The distributed force, which is defined as a vector along the surface of the refining segments, is estimated using a model where the total work can be split into reversible and irreversible work. Besides traditional refiner variables such as motor load, dilution water added and inlet- and casing pressures, measurements of temperature profiles in the refining zone and plate gaps from a fullscale CD-refiner are available as inputs. Three data sets are analyzed and it is shown that the shape of the temperature profile and the force distribution vary significantly. This means that the fiber distribution in the refining zone varies as well which affects the final development of the pulp properties. The refining segment pattern and taper play an important role when estimating the force distribution and it is stated that the force distribution close to the contraction part of the flat zone as well as the outer part of the conical section are larger than in other positions. Therefore, specific energy which can be seen as the integral of the total energy distribution along the refining segments cannot be used when describing the variations in the distributed forces.

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Alashkevich, Yuriy Davydovich, Anna Aleksandrovna Fomkina, and Aleksandra Aleksandrovna Karelina. "INTERRELATION OF INDIVIDUAL PAPER-FORMING PROPERTIES AND THE DYNAMIC VISCOSITY COEFFICIENT DURING THE GRINDING OF THE FIBROUS MASS." chemistry of plant raw material, no. 4 (December 15, 2022): 371–76. http://dx.doi.org/10.14258/jcprm.20220411374.

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The refining process is associated with the movement of large masses of fibrous suspensions in the working bodies of refining machines, which affects both the refining process itself and energy consumption when moving the fibrous suspension. In this regard, the efficiency of refining equipment can be ensured on the basis of knowledge of the hydrodynamic processes that occur during the interaction of the working bodies of refining equipment with a fibrous suspension. During the flow of fibrous suspensions, the basic rheological feature is their viscosity, which makes it possible to judge the internal forces acting in the flow. This is especially important for the bladeless refining method using the “jet-barrier” installation. In order to most fully judge the direction of the refining process (in the direction of the transverse shortening of the fibers or in the direction of their longitudinal fibrillation), it is necessary to control the paper-forming properties of the fibrous mass and the physical and mechanical properties of the castings. The publication presents an analysis of the influence of the paper-forming properties of the fibrous mass on the quality of its refining, it is advisable to find the dependence of these indicators on the rheological features of the fibrous suspension flow in the refining zone, that is, to determine the relationship of the paper-forming properties of the fibrous mass with the dynamic viscosity coefficient during the flow of the fibrous suspension in the refining zone.

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Zhang, Xiaoxin, Semiramis Friedrich, and Bernd Friedrich. "Production of High Purity Metals: A Review on Zone Refining Process." Journal of Crystallization Process and Technology 08, no. 01 (2018): 33–55. http://dx.doi.org/10.4236/jcpt.2018.81003.

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12

Sugiyama, Sumio, Meng Yi, and Jun Yanagimoto. "Refining and Recycling of Metal Scraps by Semisolid Processing." Solid State Phenomena 192-193 (October 2012): 494–99. http://dx.doi.org/10.4028/www.scientific.net/ssp.192-193.494.

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In this study, the authors propose a new refining process different from the rheorefining (a screen method) or the melt zone method. This new refining process is based on the gradient of solidification speed of the molten metal poured into a container. The molten metal in the cylindrical container firstly solidifies to columnar crystals from the wall of the container and a liquid phase gradually changes to semisolid state and progresses to the central portion of the container. After an intended semisolid state is achieved, a backward extrusion is carried out to extract the liquid phase component. The liquid component is known to contain a lot of impurity substances. For the refining trials, three aluminium alloys were selected: wrought aluminium alloy A2011, cast aluminium alloy AC4C and aluminium beverage can scraps. Backward extrusion (extraction) was applied twice, and the amount of pure Al increased from 90.59 % in the initial ingot to 96.34 % in the refined material. This new refining process can easily achieve the purification level of the rheorefining or the melt zone method.

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Geantă, Victor. "Researches Regarding the Influence of Technological Parameters on the Alloying Efficiency in Powder Injection Process." Key Engineering Materials 660 (August 2015): 113–19. http://dx.doi.org/10.4028/www.scientific.net/kem.660.113.

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The injection of the powdered materials into molten melts is a common practice in the metallurgical technology of steel refining and alloying. During process development, within the metal bath is formed a mixed three-phase with different structures depending on the parameters of the hydrodynamic injection. The “plume zone” represents a domain inside of the molten metal in which takes place the forming, coalescence and disintegration of the gas bubbles, that penetrate into the molten metal together with the powdered material. The “plume zone” is the primary contact zone between the powdered particles and the molten metal. Inside of contact zone is take place the chemical reactions between the reactive material and the metal bath components. The “plume zone” size, shape and structure are functions of the hydrodynamic parameters of the injection process, the most important being the injection speed. The size of this parameter leads at the appearance of a multitude of possible structures types of the metal bath. These structures dictate the metallurgical process efficiency in defining the steelmaking process and refining of metal bath. In the present paper are investigated and discussed the “plume zone” structures formed during injection with graphite particle of a molten steel bath and the metallurgical results obtained experimentally under the influence of the injection velocity.

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Kadrolkar, Ameya, and Neslihan Dogan. "Model Development for Refining Rates in Oxygen Steelmaking: Impact and Slag-Metal Bulk Zones." Metals 9, no. 3 (March 8, 2019): 309. http://dx.doi.org/10.3390/met9030309.

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A new approach has been adopted to predict the contribution of the impact and slag-metal bulk zones to the refining rates of impurities in a top blown oxygen steelmaking process. The knowledge pertaining to the behavior of top-jets and bottom stirring plumes (water model and industrial studies) was adapted. For the impact zone, the surface renewal generated by the top jet as well as bottom stirring plumes is incorporated in the current model, whereas in the case of slag-metal bulk zones the surface renewal is caused solely by the bottom stirring plumes. This approach helped in achieving a more explicit use of process parameters in quantifying the slag formation. The results suggest a minor contribution of these two zones to the overall refining of impurities throughout the oxygen blow.

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Medovar, L., G. Polishko, G. Stovpchenko, V. Kostin, A. Tunik, and A. Sybir. "Electroslag refining with liquid metal for composite rotor manufacturing." Archives of Materials Science and Engineering 2, no. 91 (June 1, 2018): 49–55. http://dx.doi.org/10.5604/01.3001.0012.5489.

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Purpose: To develop novel ESR based process for composite ingot with shallow transition zone between layers in order to produce efficient heavy-weight rotors for steam turbines. Design/methodology/approach: The nowadays heavy-weight rotors for steam turbines for power plants are monoblock or two or more layer in length composite part facilitating operation in different zones withstanding various loads and working medium. However, the joining of various steel in composite rotors by welding has low productivity. The ESR now is recognised as the best available technology for the big-diameter and mass forgings for power generating machines, including rotor ones. The ESR affords the most favourable conditions of solidification resulting in homogenous low-segregation ingot with smooth surface and high-quality structure. The step ahead is the ESR for composite. Findings: The two-layer model ingot had produced from steel grades 12Cr13 and 35NiCrMoV12-5 were manufactured using the electroslag process with the liquid metal (ESR LM) in the CSM of 180 mm in diameter with ingot withdrawing. The transition zone in two-layer ingot had have the shallow shape and low depth with the even macrostructure without defects of the same type as both joined steels. The metal of the transition zone fully satisfies standard requirements for properties of both steel grades in the heat treated and as-cast conditions. Research limitations/implications: The ESR LM can provide both the monobloc heavy ingots with uniform structure and composites with low-stress connection between metal layers for heavyweight rotors and other critical products manufacturing.

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Curtolo, Danilo, Xiaoxin Zhang, Martin Rojas, Semiramis Friedrich, and Bernd Friedrich. "Realization of the Zone Length Measurement during Zone Refining Process via Implementation of an Infrared Camera." Applied Sciences 8, no. 6 (May 25, 2018): 875. http://dx.doi.org/10.3390/app8060875.

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Ezheiyan, M., and H. Sadeghi. "Simulation for purification process of high pure germanium by zone refining method." Journal of Crystal Growth 462 (March 2017): 1–5. http://dx.doi.org/10.1016/j.jcrysgro.2017.01.012.

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Zhou, Xiao Lei, Zhe Shi, and Gui Fang Zhang. "Argon Blowing Technology Using in the LF Refining." Applied Mechanics and Materials 696 (November 2014): 66–69. http://dx.doi.org/10.4028/www.scientific.net/amm.696.66.

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The process of LF Refining is introduced in this paper. Because the LF ladle furnace has the advantages are widely used and developed in many companies. The argon is blown into the ladle, so the purpose of refining is achieved. The argon stirring can accelerate the chemical reaction between slag and steel. In the circulation process, large inclusion and deoxidation product in the lower region transfer into the slag. The material transfer between steel and slag can be accelerated. At the same time, argon stirring can make molten steel composition and temperature uniformity. Thus, the ladle of blowing argon can be roughly divided into three important flow region has been introduced. Two-phase region, the top horizontal flow zone and recirculation zone exists in the ladle.

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PRASAD, D. S., N. R. MUNIRATHNAM, J. V. RAO, and T. L. PRAKASH. "DETERMINATION OF EFFECTIVE DISTRIBUTION COEFFICIENT OF IMPURITIES DURING ZONE REFINING OF TELLURIUM." International Journal of Modern Physics B 22, no. 16 (June 30, 2008): 2583–88. http://dx.doi.org/10.1142/s0217979208039605.

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Knowledge of distribution coefficient values is essential in estimating the refining efficiency, and plays an important role during the purification process, typically zone refining. The effective distribution coefficient "K eff " of impurities Se , Fe , Cr and Pb in tellurium was determined in the present study and found to be 0.48, 0.05, 0.25 and 0.19, respectively. The results are validated by comparing with the available published data, and we observed a difference of less than one order, which was reasonably comparable. The influence of "K eff " on zone refining efficiency was examined and it was noticed that the effective distribution coefficient increases with respect to the translation rate, which is minimum at an optimum lower translation rate (= 30 mm/h ). The relative solute concentration C/C0 is determined experimentally, which shows the best fit of experimental values with Pfann's equation. The impurity profile along the length of the zone refined ingot is also discussed.

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Yu, Sheng Fu, Yi Lei, and Zhi Yuan Li. "Grain Refinement Behavior of Pipeline Steel in Welding Heat Affected Zone." Materials Science Forum 575-578 (April 2008): 741–46. http://dx.doi.org/10.4028/www.scientific.net/msf.575-578.741.

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Self refining grain behavior of X80 pipeline steel in the heat affected zone was studied systematically by physical simulation method. The sizes and distribution of the inclusions which promote intra-granular ferrite nucleation were measured using the automatic image analyzer, and the figures of the intra-granular ferrite which has self refining grain behavior were observed using transmission electron microscopes with energy dispersive X-ray spectroscopy, the fracture toughness values of the coarse grain zone in the HAZ were also measured. The results show that the welding thermal cycle has nearly no effect on the sizes and distribution of the inclusions in the HAZ. The reasons of self-refining grain in the HAZ are that the small non-metallic inclusions such as MnO、 TiO、MnS、CuS and （Mn，Cu）S in X80 pipeline steel ，which can induce the nucleation of intra-granular ferrite in the welding process, and sympathetic nucleation of intra-granular ferrite makes the coarse grains refined in the HAZ. First intra-granular ferrite has large boundary energy and high density dislocation, which induce the sympathetic nucleation of intra-granular ferrite.

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Cheung, T., N. Cheung, C. M. T. Tobar, R. Caram, and A. Garcia. "Application of a Genetic Algorithm to Optimize Purification in the Zone Refining Process." Materials and Manufacturing Processes 26, no. 3 (April 11, 2011): 493–500. http://dx.doi.org/10.1080/10426914.2010.520787.

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Wang, Sen, H. S. Fang, Z. L. Jin, C. J. Zhao, and L. L. Zheng. "Integrated analysis and design optimization of germanium purification process using zone-refining technique." Journal of Crystal Growth 408 (December 2014): 42–48. http://dx.doi.org/10.1016/j.jcrysgro.2014.09.019.

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Ahlert, Marlies, and Katharina Friederike Sträter. "Refining Raiffa – Aspiration Adaptation within the Zone of Possible Ag." German Economic Review 17, no. 3 (August 1, 2016): 298–315. http://dx.doi.org/10.1111/geer.12096.

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Abstract One of the most well-known descriptive bargaining models is Raiffa’s Zone of Possible Agreements (ZOPA). We reinterpret Raiffa’s model of a price negotiation in the realm of bounded rationality by applying Simon’s theory of Satisficing. Afterward we refine Raiffa’s negotiation model using Aspiration Adaptation Theory as suggested by Sauermann, Selten, Tietz and others. We offer a model of a concession process that gives precision to the Dance of Concessions in Raiffa’s model by applying axioms of bounded rationality. Raiffa suggests a solution point derived from equity in price dimension, whereas we propose an area solution defined by equity in aspiration levels.

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Shang, Yifeng, Jun Li, and Ming Chen. "Study on the Purification Effect and Equilibrium Distribution Coefficient of Impurities during Zone Refining of Fluorene." Crystals 13, no. 8 (August 9, 2023): 1224. http://dx.doi.org/10.3390/cryst13081224.

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High-purity fluorene is widely used in optoelectronic materials, biology, medicine, and other fields. It is a kind of industrial chemical with high added value. In this paper, zone melting purification technology was used to study the purification effect of fluorene on the zone travel rate, the zone length, the zone passing number, and the zone temperature difference. The concentration distribution of fluorene and the impurities 2-methylbiphenyl, 4-methylbiphenyl, 4-methyldibenzofuran, and dibenzofunan along the moving direction of the melting zone was obtained. A one-pass zone refining model of fluorene was established; the effective distribution coefficients of the four impurities above were obtained via mathematical software fitting; and the equilibrium distribution coefficients were further calculated, which were 0.2441, 0.5850, 0.2377, and 0.3497, respectively. The k0 of all impurities was less than 1. The purification effect of fluorene can be improved by using a larger zone length in the initial zone melting purification process, a smaller zone travel rate in the whole zone melting purification process, multiple zone melting purification processes, and a larger zone temperature difference. After four zone melting purification processes, the purity of fluorene increased from 97.62% to 99.08%, which was nearly 1.5% higher than the initial purity of fluorene. Zone melting purification technology provides a new idea for the preparation of high-purity fluorene.

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Jun, Huang, Ren Qingbo, Hu Zuqi, Liu Xun, and Meng Daqiao. "Application of a Genetic Algorithm to Optimize Redistribution Process in Zone Refining of Cerium." Rare Metal Materials and Engineering 46, no. 12 (December 2017): 3633–38. http://dx.doi.org/10.1016/s1875-5372(18)30049-3.

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Cheung, Thais, Noé Cheung, and Amauri Garcia. "Application of an Artificial Intelligence Technique to Improve Purification in the Zone Refining Process." Journal of Electronic Materials 39, no. 1 (September 24, 2009): 49–55. http://dx.doi.org/10.1007/s11664-009-0947-4.

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Ferents, N. O., S. Y. Vovk, and A. S. Lyn. "EXPLOSIVE HAZARD OF SPHERICAL TANKS OF OIL AND GAS REFINING ENTERPRISES." Fire Safety, no. 34 (July 19, 2019): 91–95. http://dx.doi.org/10.32447/20786662.34.2019.15.

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Gas and oil refining enterprises receive a large amount of hydrocarbon gases, which can be used as fuel or after processing as a raw material for a number of oil refining and petrochemical processes. The fires on such objects are characterized by high speed of development, destruction of technological equipment and building structures, intensive flowing out of combustible liquids and liquefied gases, significant thermal radiation, gas pollution of the adjoining territory; Even local fires or explosions under adverse circumstances due to chain development can lead to catastrophic scales. Therefore, the problem of reliable fire protection of the oil and gas refining industry enterprises, individual units and installations is relevant. The goal of the work is investigation of the danger of accidents in spherical tanks at oil and gas refining industry enterprises. The physical and chemical properties of the liquefied gases, the conditions of the technological process, the experience of accidents on similar objects were analyzed. The results showed that during the technological process with liquefied gas the emissions of substances causing the formation of a potential explosive zones, explosions of gas and gas clouds, physical explosions of vapour, fireballs, spill fires and the spread of clouds of toxic substances were possible. In order to ensure the process, spherical tanks for liquefied gas are equipped with devices for monitoring the level, pressure, temperature; alarms of emergency level; systems of manual release of pressure; systems of safety valves with a discharge on a torch or a candle; equalizing lines between tanks and overpasses with electric locks. The breakdown hazard of spherical tanks of oil and gas refining enterprises was studied. The zone of destructive action of explosion pressure in a spherical tank with liquefied gas was calculated.

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ALSAID, DANIA, JOHN CAMERON, and YAROSLAV CHUDNOVSKY. "Effect of high-temperature drying of recycled paper on heat transfer rates and sheet properties." August 2009 8, no. 8 (September 1, 2009): 24–31. http://dx.doi.org/10.32964/tj8.8.24.

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A gas-fired paper dryer (GFPD) was evaluated in pilot- and full-scale environments. A corresponding study was done on the effect of high temperature on paper drying rates and paper properties. The process variables studied include temperature, moisture level, refining, and basis weight. In an ideal location, heat transfer rates are maximized with a minimum effect on sheet properties. Sheet curl is a function of recycling, refining, basis weight, and drying temperatures and can be minimized by correct placement of the GFPD. Results of this study indicate optimal installation location. The heat transfer coefficient is independent of the shell temperature in the constant rate drying zone and in the first following rate zone, but decreases with an increase in shell temperature in the second following rate zone. If a gas-fired dryer is located in either the constant rate zone or in the first following rate zone, the overall drying rate increases by approximately two to four percent per single gas-fired cylinder. By using several gas-fired dryers, it is possible to increase the overall drying rate by as much as 20%.

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Qi, Ya-Bing, Jun Li, Kun Zhou, Jian-Hong Luo, Yang Jin, and Bao-Ming Wang. "Study on Segregation Process and Equilibrium Distribution Coefficients of Impurities during Zone Refining of Bibenzyl." Separation Science and Technology 48, no. 5 (January 2013): 820–26. http://dx.doi.org/10.1080/01496395.2012.708381.

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Ezheiyan, Mahdi, Hossein Sadeghi, and Mohammad-Hossein Tavakoli. "Thermal Analysis Simulation of Germanium Zone Refining Process Assuming a Constant Radio-Frequency Heating Source." Chinese Physics Letters 33, no. 5 (May 2016): 058102. http://dx.doi.org/10.1088/0256-307x/33/5/058102.

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Roumié, Mohamad, Khaled Zahraman, Abdallah Zaiour, Yasser Mohanna, and Makram Hage-Ali. "Study of segregation process of impurities in molten tellurium after one pass of three conjoint zones in zone refining." Journal of Crystal Growth 289, no. 1 (March 2006): 260–68. http://dx.doi.org/10.1016/j.jcrysgro.2005.11.002.

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Pushkarenko, M., V. Kyslyakov, L. Molchanov, K. Chubin, and A. Pokhvalityy. "THERMODYNAMIC ANALYSIS OF THE TECHNOLOGICAL OPERATION OF CAST IRON REFINING WITH A MIXTURE OF OXIDE COMPONENTS OF THE CaO-FeO-Na2CO3 SYSTEM." Collection of scholarly papers of Dniprovsk State Technical University (Technical Sciences) 2, no. 41 (December 19, 2022): 26–35. http://dx.doi.org/10.31319/2519-2884.41.2022.3.

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At present, at the metallurgical plants of Ukraine, a charge with an unstable chemical composition is used, which leads to significant fluctuations in temperature, the content of sulfur, silicon in cast iron and to a significant decrease in the technical and economic indicators of the further process of the production of iron-carbon semi-products. The application of standard technology of step-by-step multi-stage refining of cast iron from sulfur, silicon and phosphorus leads to an increasemelting cycle, a significant decrease in temperature, which reduces the technical and economic indicators of converter melting. Therefore, studies of the processes of one-stage removal of sulfur and silicon from liquid cast iron are relevant for the development of recommendations for reagents and technology of complex treatment of cast iron before steelmaking processing. The purpose of the work is to clarify the features of the physicochemical transformations occurring in the volume of liquid cast iron when the refining mixture of the CaO-FeO-Na2CO3 system is injected when the carrier gas is supplied in the jet. Information on the interaction of melt components with oxidation products formed in the zone of action of the gas jet was summarized, and the dependence of lgKp on temperature was constructed for possible reactions of chemical transformationsA thermodynamic analysis of the refining process was carried out due to the injection of the refining mixture of the CaO-FeO-Na2CO3 system using different carrier gases. It has been established that silicon removal processes mainly take place in the zone of direct impact of the gas-powder jet on the melt, and the silicon dioxin formed at the same time is effectively bound into dicalcium silicate. Removal of sulfur from the melt proceeds directly due to the interaction of elements of the melt with products formed in the zone of influence of the gas-powder jet on liquid cast iron and is based on desulfurization with soda in the presence of high concentrations of soda in the melt.

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Chen, Changyong, Zhouhua Jiang, Yang Li, Meng Sun, Kui Chen, Qi Wang, and Huabing Li. "Effect of Na2O and Rb2O on Inclusion Removal in C96V Saw Wire Steels Using Low-Basicity LF (Ladle Furnace) Refining Slags." Metals 8, no. 9 (September 3, 2018): 691. http://dx.doi.org/10.3390/met8090691.

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Inclusion removal and modification of C96V saw wire steel using Na2O- and Rb2O- containing novel low-basicity LF (ladle furnace) Refining Slags have been researched. The results indicated that the addition of Na2O deteriorates inclusion removal; by contrast, the addition of Rb2O seems to significantly enhance inclusion removal. In detail, Rb2O can improve the cleanliness in the as-quenched C96V saw wire steel melts compared to preexisting synthetic LF refining slag compositions: (i) The average inclusion diameter experienced a remarkable decrease after reaction between the liquid steel and the synthetic LF refining slag; (ii) In addition, the number of inclusions also suffered from a dramatic decrease, with the reaction time increasing from 900 to 2700 s (15 to 45 min); (iii) Furthermore, both of the MnO-SiO2-Al2O3 and CaO-SiO2-Al2O3 inclusion system mainly concentrated in the low melting zone when the composition of Rb2O in synthetic refining slag was ≥5.0 wt%. This is mainly because Na2O significantly reduces the viscosity of refining slag, while Rb2O increases it. Then, there are two remarkable influences causing the increase of viscosity of refining slag with the addition of Rb2O: the inclusions can be sufficiently entrained within the slag once absorbed due to the significant increase in the viscosity; and the slag entrapment during refining process weakened dramatically.

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Theiss, LuAnn, and Gerald L. Ullman. "Minimizing Work Zone Mobility Impacts using Project Coordination." Transportation Research Record: Journal of the Transportation Research Board 2673, no. 2 (February 2019): 209–19. http://dx.doi.org/10.1177/0361198118822317.

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Under the Every Day Counts program, the Federal Highway Administration has been promoting technologies and practices that can shorten the project delivery process, enhance durability and safety, reduce congestion, and improve environmental sustainability. The focus is on providing efficiency through technology and collaboration. This includes strategies for Project Coordination (PC) which can be applied to a single project, or more commonly, among multiple projects within a corridor, network, or region, and possibly across agency jurisdictions, to minimize work zone impacts and produce time and cost savings. The purpose of this document is to provide guidance on implementing PC in the planning, design, and delivery phases of projects. It summarizes key steps for successfully implementing PC, using a systematic approach to meet a specific set of clearly defined objectives. The steps include: establishing the PC vision; developing details of how PC will occur; educating and informing personnel and stakeholders; implementing the PC process; and refining the process. A case study of PC in Texas is included to demonstrate successful application of the approach.

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Singh, Tanvir, SK Tiwari, and DK Shukla. "Effect of nano-sized particles on grain structure and mechanical behavior of friction stir welded Al-nanocomposites." Proceedings of the Institution of Mechanical Engineers, Part L: Journal of Materials: Design and Applications 234, no. 2 (November 4, 2019): 274–90. http://dx.doi.org/10.1177/1464420719885156.

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Weldability of heat-treatable 6061-T6 aluminum alloy results in deterioration of mechanical properties due to dissolution of strengthening precipitates in the nugget zone of friction stir welded joints. These properties were improved by addition of reinforcement particles in the weld joint line. In the present work, attempts were made to produce 6061-T6 Al-based nanocomposites using the friction stir welding process by incorporating titanium oxide nanoparticles into the aluminum matrix for microstructure refining of the nugget zone and prevent the grain growth in the heat-affected zone. The effect of addition of nanoparticles on the evolution of grains structure and mechanical behavior of friction stir welded samples based on different combinations of rotational and travel speed was studied and discussed. Results revealed that the unreinforced samples were successfully welded at both low and high heat inputs, whereas the reinforced samples are not feasible at tool rotational speed (ω) < 2000 r/min and transverse speed (v) > 70 mm/min, respectively. The significant refining of grains in the nugget zone is possible with addition of nanoparticles via the Zener-pinning effect. A more pronounced increment in tensile strength, microhardness, and wear properties was observed compared to sample without nanoparticles under the same processing parameters due to embedment of nano-sized particles in the weld nugget zone.

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Chan, Chun Y., Philip B. Prangnell, and Simon J. Barnes. "Analysis of the Homogeneity of Particle Refinement in Friction Stir Processing Al-Si Alloys." Advanced Materials Research 89-91 (January 2010): 85–90. http://dx.doi.org/10.4028/www.scientific.net/amr.89-91.85.

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Friction Stir Processing (FSP) has potential for locally enhancing the properties of Al-Si alloy castings, for demanding applications within the automotive industry, by greatly refining the second phase particle size. In the present study, the homogeneity of particle refinement and second phase spatial distribution within the process zone, as well as the relationship to the processing parameters, were investigated in a gravity die cast Al-Si LM24/A380 alloy, subjected to a range of FSP conditions. Detailed image analysis and the dirichlet tessellation method were used to quantify particle clustering. ‘Stop-action’ experiments were also used to study the process of particle break up, by following the behaviour through the deformation zone surrounding the tool.

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Gotenbruck, Michaela, Danilo C. Curtolo, Semiramis Friedrich, Clemens J. Müller, Nico Rademacher, and Bernd Friedrich. "Static Crystallization, an Alternative Methodology for Synthesis of High-Purity Aluminum." Metals 13, no. 2 (January 31, 2023): 280. http://dx.doi.org/10.3390/met13020280.

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Due to its outstanding properties and wide range of applications, high-purity to ultra-high-purity aluminum represents a strategic material for meeting the future challenges of the 21st century. The purification of aluminum towards higher purity levels is usually performed via a combination of three-layer electrolytic refining and fractional crystallization using zone-melting processes. New methods and processes are being researched in the search for more time-saving and less costly options. Metal refining using static crystallization represents one of these new, alternative processes. This work investigated the feasibility of metal refining by means of a static crystallization furnace using aluminum as an example metal. In particular, the effects of the temperature gradient and the cooling rate on the reduction factor of the impurities iron (Fe), silicon (Si), and lead (Pb) were investigated. In addition, the effects of the process parameters on the grain structure formed were investigated, and correlations to the resulting purity level were made.

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Wang, Xiang Jie, Fang Yu, Peng Wei Li, Wei Sun, Hong Juan Tan, Lei Li, and Jian Zhong Cui. "Effects of Electromagnetic Agitation on Crystal Growth during the Pure Aluminum Slow Cooling Process." Materials Science Forum 993 (May 2020): 398–403. http://dx.doi.org/10.4028/www.scientific.net/msf.993.398.

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Refining grains are important to obtain sound cast billets suitable for further processing. The structure refinement of low frequency electromagnetic field (LFEF) during the aluminum alloy semi-continuous casting process has been confirmed by many researchers. In this work, effects of the electromagnetic agitation on the crystal growth were investigated during the pure aluminum slow cooling process. The results showed that the grain refinement effect by electromagnetic agitation mainly occurred at the first half period of crystal growth. With increasing of applying LFEF treated time, the fine grain occupied the whole section of ingot, and the ratio of fine grain zone to the whole section was proportional to the treated time.

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Chen, Xingrun, Guoguang Cheng, Yuyang Hou, and Jingyu Li. "Inclusions evolution during the LF refining process of 439 ultra-pure ferritic stainless steel." Metallurgical Research & Technology 116, no. 6 (2019): 619. http://dx.doi.org/10.1051/metal/2019048.

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The morphology, composition, size, and number of inclusions in 439 ultra-pure ferritic stainless steel samples were analyzed using an automatic scanning electron microscope combined with an energy-dispersive X-ray spectrometer. In addition, the appropriate contents of titanium, aluminum, and calcium were analyzed through the coupling of thermodynamics calculation and experimental results. CaO-Al2O3-MgO inclusions existed in the 439 steel before Ti additions in the ladle furnace (LF) refining process. After Ti addition in the LF refining process, the inclusions were transformed into CaO-Al2O3-MgO-TiOx inclusions. The evolution of these inclusions was consistent with thermodynamic calculation, which indicated that when the Al, Ca, and Ti contents were within a reasonable range, Ca treatment could significantly modify the aluminate and spinel to form CaO-Al2O3-MgO liquid inclusions. In addition, the compositions of inclusions after the addition of titanium were mostly located in the Al2O3-TiOx stable phase. The collision of the CaO-Al2O3-MgO liquid inclusions and Al2O3-TiOx inclusions resulted in the modification of the CaO-Al2O3-MgO-TiOx inclusions. The compositions of most inclusions were located in the liquid zone. The control range of the aluminum, calcium, and titanium contents was obtained: logAl% ≥ 1.481logTi% − 0.7166, Ca% ≥ 34.926(Al%)3 − 3.3056(Al%)2 + 0.1112(Al%) − 0.0003.

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Gupta, Siddharth, Pratik Joshi, Ritesh Sachan, and Jagdish Narayan. "Fabricating Graphene Oxide/h-BN Metal Insulator Semiconductor Diodes by Nanosecond Laser Irradiation." Nanomaterials 12, no. 15 (August 8, 2022): 2718. http://dx.doi.org/10.3390/nano12152718.

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To employ graphene’s rapid conduction in 2D devices, a heterostructure with a broad bandgap dielectric that is free of traps is required. Within this paradigm, h-BN is a good candidate because of its graphene-like structure and ultrawide bandgap. We show how to make such a heterostructure by irradiating alternating layers of a-C and a-BN film with a nanosecond excimer laser, melting and zone-refining constituent layers in the process. With Raman spectroscopy and ToF-SIMS analyses, we demonstrate this localized zone-refining into phase-pure h-BN and rGO films with distinct Raman vibrational modes and SIMS profile flattening after laser irradiation. Furthermore, in comparing laser-irradiated rGO-Si MS and rGO/h-BN/Si MIS diodes, the MIS diodes exhibit an increased turn-on voltage (4.4 V) and low leakage current. The MIS diode I-V characteristics reveal direct tunneling conduction under low bias and Fowler-Nordheim tunneling in the high-voltage regime, turning the MIS diode ON with improved rectification and current flow. This study sheds light on the nonequilibrium approaches to engineering h-BN and graphene heterostructures for ultrathin field effect transistor device development.

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Li, Mingxu, Qingle Tian, Meizhen Wu, Jubo Peng, Jiatao Zhang, Lishi Chen, Xingwei Lu, Zhishuai Xu, and Hongxing Zheng. "Numerical simulation analysis on solute redistribution of In–1 wt% Sn alloy during multipass vertical zone refining process." Journal of Crystal Growth 565 (July 2021): 126156. http://dx.doi.org/10.1016/j.jcrysgro.2021.126156.

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42

Chollet, S., A. Kotland, JM Autret, G. Calmels, C. Diard, J. Hubert, L. Marchal, and JH Renault. "Purification of alkaloids from Catharanthus roseus by pH-zone refining centrifugal partition chromatography: process intensification and scale up." Planta Medica 81, S 01 (December 14, 2016): S1—S381. http://dx.doi.org/10.1055/s-0036-1596139.

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43

Madhavan, Nirmal, Geoffrey A. Brooks, M. Akbar Rhamdhani, Bapin K. Rout, and Aart Overbosch. "Global Droplet Heat Transfer in Oxygen Steelmaking Process." Metals 12, no. 6 (June 10, 2022): 992. http://dx.doi.org/10.3390/met12060992.

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Generated droplets in a basic oxygen furnace (BOF) process create an interfacial area between metal and slag/emulsion that helps in heat transfer during different stages of the blowing period. Previous studies have developed extensive models to understand bloating behavior and overall refining kinetics contributed by the droplets in a BOF process. Except for the recent study on single droplet heat transfer by the current authors, no studies in the open literature have addressed the heat transfer contributed by droplets in a BOF. The present work is an extension of single droplet heat transfer, wherein a global droplet heat transfer model is developed by integrating kinetic and dynamic aspects of generated droplets during the blowing period. The model was developed based on previous chemical kinetic studies and input values from plant trials. The results from the global droplet heat transfer model are integrated into the overall zone heat balance calculations to predict the temperature evolution profile of hot spot, slag, and hot metal zones during the blowing period. The results highlight that the hot spot temperature ranges from 1900 °C to 2090 °C, with a peak value of around 2300 °C observed during the middle of the blow. Furthermore, computing the overall droplet heat transfer efficiency, it was observed that the droplets transfer 90% of the heat to the slag up to the first 10 min of the blow, and then the heat transfer efficiency drops towards the end of the blow.

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Kislyakov, V. H., D. M. Togobitskaya, L. S. Molchanov, O. L. Rudenko, and M. V. Pushkarenko. "Selection of basic components of slag-forming mixture for single-step removal of impurities from cast iron." Fundamental and applied problems of ferrous metallurgy 36 (2022): 134–41. http://dx.doi.org/10.52150/2522-9117-2022-36-134-141.

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The article is devoted to research on the development of a variant of the component composition of the slag-forming mixture during complex processing of cast iron for the detection of such impurities as silicon, sulfur and phosphorus. The purpose of the work is to study the composition of soda-containing slag on its physical and chemical properties and to identify the optimal ratio of refining slag components. Using the structure of the model of the process of processing cast iron by injecting reagents into the melt volume through the immersion nozzle, the thermodynamic probability of reactions occurring in the primary zone (at the outlet of the reagents from the nozzle of the nozzle) and the secondary reaction zone formed when the reaction products flowing in primary reaction zone. The value of the equilibrium constants of the corresponding reactions was calculated to assess the priority of the course of reactions of the interaction of system components in the primary reaction zone. The conducted thermodynamic analysis of the simultaneous removal of sulfur and silicon from cast iron by blowing powdered lime in a stream of oxygen and introducing additional reduction into the melt made it possible to state that during the oxidation of silicon with gaseous oxygen for desulfurization of cast iron with the resulting slag, it is advisable to additionally introduce a reducing agent into the melt. The technological parameters and main results of the experimental study of the process of out-of-furnace desiliconization and desulfurization of cast iron by blowing slag-forming materials into 350 kg buckets at the experimental plant are presented. Based on the results, data were obtained on the influence of the basicity of soda-containing slag on its viscosity and temperature. Using the theory of directional chemical bonding, the influence of the basicity of soda-containing slag on its physical and chemical properties was studied, and the optimal ratios of refining slag components were found.

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Wang, Xiao, Yuqin Liu, Bin Yang, Yanling Geng, Dahui Liu, and Luqi Huang. "Enrichment and Separation of Sinomenine and Acutumine fromSinomenium acutumby pH-Zone-Refining Counter-Current Chromatography." Separation Science and Technology 46, no. 9 (May 15, 2011): 1534–38. http://dx.doi.org/10.1080/01496395.2011.563259.

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C, Ramesh, Mohammed Tharwan, P. Manoj Kumar, and Dawit Tafesse Gebreyohannes. "Microstructural and Mechanical Characteristics of Pure-Cu/brass Dissimilar Joints Welded by Friction Stir Welding Using Various Process Parameters." Advances in Materials Science and Engineering 2022 (September 2, 2022): 1–10. http://dx.doi.org/10.1155/2022/2234352.

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FSW (friction stir welding) is a solid-state joining method that attracts interest from all industries. The influence of various tool rotational speeds on the microstructure and mechanical characteristics of dissimilar pure Cu-brass joints has been investigated. The travel speed and vertical load were kept constant in the welding trials, at 40 mm/min and 10 kN, respectively, while the tool rotational speed varied from 1000 to 1400 rpm. The increase of the rotational speed to 1400 rpm resulted in degradation of the mechanical properties. The stir zone grain structure was refined; however, the grain size was irregular. Grain refining occurs due to a continuous and discontinuous dynamic recrystallization mechanism. In the grain interior, there were many large dislocations, identifying that incomplete recrystallization took part within the SZ. Instead, the lower rotational speed, i.e., 1000 rpm, led to more uniform grain refinement in the SZ. Moreover, in contrast to the welded zone where very fine grains exist, the base metal and thermomechanically heat-affected zone display coarser grains. Because of the microstructural modification, the stir zone’s mechanical characteristics were higher than the base materials, and the mechanical strength and plasticity were simultaneously upgraded. These results indicate that the size of the grains is independent of rotational speed. And mechanical properties like hardness and impact strength decreased as the rotational speed increased.

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Ghosh, K., V. N. Mani, and S. Dhar. "A computational study and experimental validation of zone refining process for ultra-purification of gallium for opto-electronic applications." Transactions of the Indian Institute of Metals 61, no. 2-3 (April 2008): 201–6. http://dx.doi.org/10.1007/s12666-008-0038-x.

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Dian-Qiao, Geng, Hong Lei, and Ji-Cheng He. "Decarburization and Inclusion Removal Process in Single Snorkel Vacuum Degasser." High Temperature Materials and Processes 36, no. 5 (May 24, 2017): 523–30. http://dx.doi.org/10.1515/htmp-2016-0124.

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AbstractIn the current work, the coupled mathematical models for decarburization, fluid flow model and inclusion collision-aggregation model were solved to investigate the spatial distribution of carbon, inclusion’s collision-aggregation and removal in a single snorkel vacuum refining furnace (SSF). The numerical results show that the turbulence kinetic energy of ladle in SSF is much greater than that in RH, which can shrink the dead zone and prompt the mixing in the ladle. The overall decarburization reaction rate can be described as a first-order reaction. On the condition of the same gas flow rate, the volumetric mass transfer coefficient for decarburization in SSF is almost twenty times bigger than that in RH, which leads to a much greater decarburization rate in SSF. The spatial distribution of carbon mass fraction in SSF is quite different from that in RH. There is the greater mass fraction of carbon at the recirculation zone under up-snorkel in RH, but this phenomenon disappears in SSF. The inclusion removal can be simplified as the mass transfer between liquid steel to slag, refractory wall and bubble surface. And the overall inclusion removal rate can be regarded as a first-order reaction. The volumetric mass transfer coefficient for inclusion removal in SSF is about three times as that in RH, the inclusion removal rate in SSF is greater than that in RH. The inclusions with different size have different removal rates in SSF. For inclusion flotation after deoxidization, the treatment time in SSF is less than that in RH.

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Weglowski, Marek Stanisław. "Experimental Study and Response Surface Methodology for Investigation of FSP Process." Archive of Mechanical Engineering 61, no. 4 (December 1, 2014): 539–52. http://dx.doi.org/10.2478/meceng-2014-0031.

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Abstract The article presents the effect of rotational and travelling speed and down force on the spindle torque acting on the tool in Friction Stir Processing (FSP) process. The response surface methodology (RSM) was applied to find a dependence combining the spindle torque acting on the tool with the rotational speed, travelling speed and the down force. The linear and quadratic models with interaction between parameters were used. A better fitting was achieved for a quadratic model. The studies have shown that the increase in rotational speed causes a decrease in the torque while the increase in travelling speed and down force causes an increase in the torque. The tests were conducted on casting aluminium alloy AlSi9Mg. Metallography examination has revealed that the application of FSP process results in a decrease in the porosity in the modified material and microstructure refining in the stir zone. The segregation of Si and Fe elements was evident in the parent material, while in the friction stir processed area this distribution was significantly uniform.

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Shim, Moonsoo, Ho-Gil Choi, Jeong-Hun Choi, Kyung-Woo Yi, and Jong-Hyeon Lee. "Separation of Cs and Sr from LiCl-KCl eutectic salt via a zone-refining process for pyroprocessing waste salt minimization." Journal of Nuclear Materials 491 (August 2017): 9–17. http://dx.doi.org/10.1016/j.jnucmat.2017.04.036.

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Journal articles on the topic 'Zone Refining Process'

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