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By Kenji Matsuzaki

A mathematical simulation model of the Imperial Smelting Furnace operation has been developed for purpose of improving the furnace operation. The model consists of top, shaft and bottom regions, Analysis in the shaft region is based on differential heat and materials balances taking account of reaction kinetics and heat transfer rates, and those in the top and the bottom regions are based on heat and materials balances under a steady-state condition, Longitudinal distributions of process variables such as temperatures of gas, sinter and coke, gas composition and fractional conversion under a practical operating condition were calculated, With this model, the furnace performance under various operating conditions also can be shown reasonably predicted,

Jan 1, 2003

By Guo Xueyi

The morphological characteristics of the nickel particles electrodeposited from chloride dominant aqueous solution was investigated. The effects of the electrolyte constituents, the parameters for the electro-deposition on the morphology of the nickel particles were addressed. It is evidenced that not only the particle size but also the morphology of the deposited nickel particles strongly depend on the electrolyte constituents and technical operation conditions. The electro-crystallization mechanism of the metallic nickel particles deposited at high current density was elucidated. The ultra-fine nickel particles with flake, nodular or dendrite shape may be produced by controlling the duration for electro-deposition.

Jan 1, 2003

By Zhucheng Huang, Zhikai Liang, Lingyun Yi, Tao Jiang

"In this study, reduction of iron ore pellets was carried out at 800-950°C by simulating the atmosphere of typical coal gasification gas. The effects of temperature, gas composition and reduction degree on swelling were investigated respectively. Reduction degree was obtained according to the weight loss records. And volume changes of pellets during reduction were evaluated by infrared photography. Results showed that the pellet swelling increased with temperature and decreased slightly with hydrogen content in the reducing gas. The swelling peaked when reduction degree reached about 40% and then decreased to be stable finally. The microstructures of pellets during reduction were examined by reflected light microscope and relatively rational explanations were proposed for their swelling behaviors.PrefaceDirect reduction iron is an important and indispensable raw material for high-purified and high-quality steel in the electric furnace smelting. Gas-based shaft furnace direct reduction process has very strong competitative ability; however, this technique requires natural gas as reducing agent, so its development has been restricted by gas source and area. Compared with gas-based reduction method, coal based reduction method has the disadvantages of higher production cost and lower productivity. In China, coal resources are abundant and coal gasification technology is mature, and the development of coal gasification shaft furnace direct reduction process is promising. [1] The gasification methods of fixed bed method (Lurgi method), fluidized bed method (Undok method), airflow bed method (Texaco coal water slurry method and Shell dry powder coal method) have been put into use successfully. These syngas generated by different methods can meet the actual production requirement of shaft furnace. However, the compositions of the effective reduction gas in the syngas are quite different. The ratios of hydrogen and carbon monoxide (H2/CO) of Undok or Shell coal gas, Texaco coal gas and Lurgi coal gas are 0.4, 0.6~ 1.0 and 1.6~2.3, respectively. [2] In the coal gas direct reduction process, the swelling behavior of iron ore pellets is various due to the differences of the gas composition, reduction temperature and reduction degree, and it seriously affects the normal operation ofDRI production. [3-9] Therefore, the research on the swelling behavior and its mechanism of iron ore pellets in direct reduction were carried out in this paper."

Jan 1, 2013

By R. Hammen

Processes are needed to rapidly and cost-effectively produce highly pure lithium salts for the rechargeable battery sector. Lithium purification is a chemical engineering challenge, due to the low concentration of lithium compared to sodium, potassium, magnesium, calcium, and transition metal ions commonly occurring in lithium brine resources. We describe a Solid Phase Extraction (SPE) process that rejects sodium and potassium, while binding lithium and other higher valent ions. Lithium is then harvested by selective displacement from the SPE column. The rapid equilibration kinetics of SPE composites enables these ion separations to occur in a small SPE column and in one column stage. The chemical parameters of the process are described.

By Y. Z. Zhang

Electrochemical oxidation of arsenopyrite in ferric sulphate media in the absence and presence of bacteria T jerrooxidans has been investigated for the purpose of understanding the dissolution chemistry of arsenopyrite and the bacteria attack mechanism. Mixed potential, polarization resistance measurements, polarization curve, cyclic voltammetry experiments were conducted in a ferric sulphate medium of 10g/L FeH, temp.25-35°C, pH 1.5-2.5 in the absence and presence of bacteria Tjerrooxidans, respectively. For the anodic process, a two-step reaction sequence is suggested by the electrochemical measurements. The initial step at a low potential is described by:

Jan 1, 1996

By Jiang Feng, Zhang Libo, Peng Jinhui, Guo Zhanyong, Ju Shaohua, Lei Ting

The clean utilization of the residue containing chloride, CuCl residue, produced from zinc hydrometallurgy is very important for the recycle of valuable metals. And drying is the main process in recycling. In this study, response surface methodology was used to optimize operating conditions of the drying of CuCl residue in a convection oven and desirability function used as the methodology for the optimization. Optimization factors were air temperature (80–100°C), material thickness (10–25mm) and process time (80–120min) while investigated responses was final moisture content. The optimum conditions were found to be the temperature of 95.48°C with the material thickness of 13.47mm for the process time of 89.48 min. Under optimum conditions, the predicted moisture content of CuCl residue was 4.11% while the experimental date was 4.13%. The experimental value after process optimization was found to agree satisfactory with the predicted value. After drying, XRD was used to analyze the main phases of CuCl residue. The CuCl residue is made up of CuCl,Cu2O, ZnS and other compounds.

Jan 1, 2015

By E. V. Redin, B. A. Dubrovsky, E. V. Knyazev, A. I. Starikov

"Ti-V magnetite is one of the most abundant composite ore resources in the world. This ore cannot be fully processed via blast furnace technology because of high content of Ti02. According to the investigations carried out in the USA and Japan ITmk3 RHF (Rotary Hearth Furnace) technology is a breakthrough in Ironmaking. Reduction, melting and slag removal can be achieved in just 10 min. The main objective of the investigation is to establish optimum operation conditions for the production of iron nuggets from Ti-V magnetite ore via the ITmk3 by means of the lab scale testing. Samples of ore from the Maly Kuybas deposit (Southern Ural), carbon reductant and fluxes were chemically analyzed. Green pellets were processed via a lab chamber furnace to simulate RHF conditions. The nuggets and slag were chemically analyzed. This preliminary test work provides valuable information which may be used for large-scale testing in a commercially sized RHF.IntroductionThe ITmk3 process upon which this paper focuses was developed by Kobe Steel in its research facilities [l]. After pilot testing at Kobe Steel's Kakogava Works in 1999-2004 the pilot demonstration plant was built and operations were successfully carried out by Mesabi Nugget joint venture in 2002-2004. Steel Dynamics put into operation the commercial plant at the Mesabi Nugget site in Hoyt Lakes (Minnesota) in 2010. Results were consistent with nugget characteristics confirming ITmk3' s flexibility with respect to raw material inputs. At the same time, no research in the field of nugget from the Ti-V magnetite bearing ore with high content of Ti02 and Alz03 has been done. It is well known, if a lot of Ti02 and Alz03 enter the blast furnace, slag becomes viscous. The viscous slag is obstacle for stable operation of the blast furnace. Besides, high content of Alz03 raises the melting temperature of gangue minerals disturbing the coalescence of reduced iron to the nuggets."

Jan 1, 2013

By Xi-chang Shi, Yun-feng Fu, Bai-zhen Chen, Hui Xu, Xiang Xiao

"Extracting boric acid from saline brine by boron specific ion-exchange resin was investigated. Effects of resin amount, temperature, time and stirring speed on boron adsorption rate were studied in the experiments. The results indicated that the XSC-700 resin showed excellent boron absorbability and it performed better property for elution. The maximum boron adsorption capacity was 6.16 mg/ml in the optimum conditions: the resin concentration of 5 ml/(100 ml brine), the temperature of 60°C, the time of 5-6h and the stirring speed of 100 r/min. Boron was eluted from the resin with HCl and boric acid was crystallized by evaporating the eluate. The product of boric acid was in pure form as confirmed by XRD and other analysis techniques.1 IntroductionBoron has a number of minerals in nature such as tincal, colemanite, ulexite, and kemite, etc. [1-2]. Boron and its compounds are chemical materials of significant value. The principal industrial uses of boron compounds are in the production of glass, porcelain, enamels and detergents. Other uses include fertilizers, metallurgy, and nuclear shielding [3-4]. In recent years, because of the large-scale mining boron ore, ore resources are drained gradually. With the development of science and technology, the boron mineral resources will be unsatisfied with the future requirement. There exits abundant boron resources in salt lakes which cover about 40% of the total reserves in China. If we can obtain boron from salt lakes, it will produce great economic interests [5-6]. Therefore, actively seeking boron from salt lake and other resources in suitable conditions has become a hot spot in the research organizations of boron resources development and utilization in the world [7].There are many methods such as acid crystallization, solvent extraction and ion exchange processes suggested effective for boron extraction from aqueous solutions. Acid crystallization method has the shortcomings of complicated procedures, the pollution caused by hydrochloric and other ingredients returning to salt lakes during the extraction process. Although solvent extraction process increases the boron acid recovery efficiency, the cost of production is high [8-9]. However, Chelating resin extracting boron has the characteristics of simple process, easy operation and no pollution. It was reported that chelating resins containing functional groups show a high selectivity for boron extraction [10-12]. Therefore, ion exchange technique which is now the most practical application of significance and most extensively used ha"

Jan 1, 2011

By Tianzu Yang, Weifeng Liu, Lin Chen, Wei Chen, DUCHAO ZHANG

Ni-M (Metal=Cu, Fe, Co, Mn, Zn, Cr) aerogel catalysts were tested for CH4 oxy-CO2 reforming. It was found that the Ni-Co bimetallic aerogel catalyst had the highest activity and stability in methane oxy-CO2 reforming among all the Ni-M aerogel catalysts. It exhibited a steady activity of 79 % (in terms of CH4 conversion) at 750 oC, which is the highest activity under a similar reaction condition as compared with those published in literature. Characterizations for the reduced catalysts indicated the formation of Ni-Co alloy, while other transition metals separated from Ni during the reduction process. Therefore, the active species in the Ni-Co bimetallic catalyst showed a stronger interaction than those in other Ni-M catalysts, which might be one of the main reasons for the better catalytic performance of the catalyst.

Jan 1, 2016

By Christoph Beckermann, Kai Liu, Richard A. Hardin

"A two-dimensional heat transfer model for transient simulation and control of a continuous steel slab caster is described. Slab thermal and solidification conditions are computed by the model as a function of time-varying casting speed, secondary spray cooling water flow rates and temperature, slab thickness, steel chemistry, and pouring and ambient temperatures. A solidification model that includes the effects of steel chemistry, cooling rate and mierosegregation on the solidification path is incorporated directly into the caster model. Comparisons between measured and predicted liquidus and solidus temperatures are given for two low alloy steels, and show good agreement. Predicted and measured slab surface temperatures recorded on an operating caster are compared with this transient model and show that the model can predict the temperature response at the slab surface. Results of several simulations are given to demonstrate the effects of changing casting conditions on the slab thermal profile and the solidification end-point. A control methodology suitable for online control of a continuous casting machine is described, and its ability to control the surface temperature profile by dynamically adjusting secondary spray cooling flow rates is demonstrated using the simulator. IntroductionIn order to remain competitive in today's world-wide market for continuously cast steel products, steel producers are finding that it is ever more important to implement process control and to develop a more thorough technological understanding of their casting process. By integrating process control and monitoring into both production and quality control, producers are better able to meet customers' demands for steel of the required quality, quantity, size, grade, and properties at the lowest cost. Computer models used for real-time/on-line prediction and control of continuous steel casters are fundamental tools to accomplish this. Accurate on-line prediction and control of steel solidification and heat transfer allows for more flexibility in caster operation by giving operators the ability to change casting speeds while keeping critical process parameters within required ranges. Such control 'capability also results in more uniform quality throughout an entire casting sequence from startup to shutdown. Furthermore, due to the unreliability of temperature sensors, and the lack of good sensors for important process parameters such as solidification end-point and liquid pool depth, computer-based control models are often the only available option."

Jan 1, 2000

By K. W. Cathrine Solem

Filtration of liquid aluminium is widely used in the industry for the removal of inclusions, and Ceramic Foam Filters (CFFs) are often the filtration media of choice. It is known that PH3 (phosphine) can be released from used phosphate bonded CFFs when in contact with water. Additionally, there is a need of an improved understanding of the thermal stability and the chemical reactivity of these types of filters, as there is limited information available in the public domain. In the present preliminary study, three CFFs, i.e. Substrate 1–3, with varying AlPO4 (aluminium phosphate) content were studied under controlled conditions. Samples of the substrates, as produced and in contact with 5N pure aluminium, were heat-treated in a vacuum induction furnace at 850 °C and 1300 °C, as well as thermally studied at 850 °C using a Differential Scanning Colorimeter connected to a Thermogravimetric Analyser (DSC-TG). All tests were performed under an inert atmosphere of argon (Ar). Mass changes of ∼0.001 % were registered for the pure substrates, and 0.003-0.10 % when in contact with aluminium. In the latter case, diffusion of P (phosphorous) from the bulk of the substrate to the interface was established to have taken place. A colour change, from white to orange/brown, was also observed at the interface, which is a clear sign that a chemical reaction has taken place. As a result, the thermal stability of the substrates can be questioned under present conditions.

By Y. Yang, S. Peelman, J. Sietsma, Z. H. I. Sun

The rare earth elements (REEs) present in the Kiruna iron ore mine tailings are being considered as a new REE resource for the EU. These tailings, after beneficiation, contain approximately 5000 ppm of rare earths, concentrated in apatite and monazite minerals. To economically extract the REEs from these tailings the phosphorous contained within the apatite must also be extracted and the waste production of the process should be minimal. To achieve the extraction of REEs and phosphorous HCl and HNO3 were investigated as possible leaching agents. Based on the results a leaching process using HNO3 is proposed. This process produces H3PO4 from the apatite while simultaneously dissolving the REEs. The resulting leach liquor is then cooled to remove the unwanted Ca as Ca(NO3)2. Analysis of the leach liquor reveals extraction ratios of between 75% and 100% for the heavy REE (e.g. Y, Eu, Dy, …) and below 40% from the light REEs (i.e. Ce, La). Full phosphorous extraction was also achieved.

Jan 1, 2016

By W. K. Collins

Engineered Scavenger Compounds (ESCs), developed by the U.S. Bureau of Mines, are a novel class of compounds that can selectively recover a desired element from a solid or molten alloy. Lithium titanate (Li2Ti3O7 or L'20-3T'02) is being used as an ESC to recover lithium (Li) from Aluminum-Lithium (Al-Li) alloys. X-ray diffraction measurements have shown that lithium titanate undergoes a phase change from an orthorhombic structure to a hexagonal structure. This change is due to the incorporation of Li in the matrix of the material and the effect of temperature. Although both are metastable, the hexagonal phase that forms during the scavenging of Li from Al-Li alloys appears to be the more stable phase. Recovering Li from the ESC by electrodeposition does not cause the structure to revert to the orthorhombic phase. Both the orthorhombic and the hexagonal structures of Li2Ti3O7 have similar scavenging capacities for Li. This paper proposes a new mechanism for the phase transformation.

Jan 1, 1993

By F. J. J. van Loo, J. K. Kivilahti, M. Paulasto

"Activation mechanism and interfacial reactions in brazing of ShN4 with different AgCuTi filler alloys has been investigated thermodynamically and experimentally. During brazing the AgCuTi filler alloy is divided into two liquids Ll and L2, where the (Cu,Ti)-rich liquid L2 gathers at the ShN4 interface and reacts with it. The concentration of Ti in L2 is high, but due to the strong attractive interaction between Cu and Ti, the activity of Ti in L2 is considerably low. In reaction between ShN4 and Cu-containing brazes a Ti-Cu-Si-N compound is typically formed at the interface. In absence of Cu, in joints brazed with AgTi based filler alloys, extremely Ti-rich solution reacts with ShN4 and as reaction products TiN and TisSh[N] are formed. IntroductionAdvanced ceramics like silicon nitride are increasingly used as structural components in demanding applications as well as in electronics industry. Complex, multicomponent structures for engineering applications generally require interconnections and therefore joinability of ceramics largely determines the possibilities of metal-ceramic structures to enable demanding functions. Brazing with active filler metals, most of which are based on the Ag-Cu-Ti system, has been commonly employed for joining of ShN4 to other ceramics and metals. The interfacial microstructures formed when ShN4 is brazed with Ag-Cu-Ti braze alloys have been discussed in several recent studies [1-7]. However, some inconsistencies exist in the reported results. The formation of layers of TiN and titanium silicides, possibly TisSh, next to the ShN4 has been reported in several studies [1-5], while in another investigation, a layer of an orthorhombic TiSi- Cu-N phase was found beyond the TiN layer [6]. In few investigations the thermodynamics of the ShN4-Ti system has been considered, but no detailed thermodynamic analysis of the chemical interactions between the braze and ShN4 has been provided. In order to resolve which chemical reactions are possible under various joining conditions and thereby to be able to control the brazing of ShN4 the reactions in brazing has to be studied using both microstructural and thermodynamic analysis."

Jan 1, 1996

By Anxiang Wang, Kunhua Wu, Yifu Li, Junjie Xu, Yongnian Dai, Bin Yang, Lingxin Kong

In this study, the saturated vapor pressures of tin (Sn) and antimony (Sb), the separation coefficient and the vapor-liquid phase equilibrium of Sn-Sb alloy were theoretically analyzed, which demonstrate that it is possible to separate Sn and Sb by vacuum distillation. The process parameters of vacuum distillation, including the distillation temperature, distillation time and alloy mass (thickness of raw materials) on the direct yield of Sn and the content of Sn in liquid phase were investigated by using single factor experiments. The preliminary results show that the direct yield and the content of Sn are 98.77 wt.% and 96.01% with the optimized distillation conditions of a distillation temperature of 1473 K, a distillation t ime for 45 min and a Sn-Sb alloy mass of 125 g ( thickness o f 8 mm). The distillation parameters in the study provide effective and convenient conditions on separation of Sn-Sb alloy.

Jan 1, 2016

By Gabriel Riveros

Fire refining of copper consists of two stages copper oxidation and copper reduction. Very frequently the capacity of the anode furnace is determined by the rate of copper reduction. The analysis of factors affecting the rate of the oxygen reduction from a liquid copper with solid carbon or injected hydrocarbons pointed out the role of the mass transfer in a liquid copper in final stage of the reduction. Experimental results of copper reduction with graphite and injected natural gas in laboratory- scale crucibles showed two stages of the reduction process with a sharp change of the controlling mechanism. The estimated dynamic surface area of gas bubbles based on the measured bubble frequency and the gas flowrate allowed for the detennination of the reaction constant as a degree of the partial pre-combustion of the air/natural gas mix. The variation of the used reductant as a function of the oxygen concentration and temperature has been evaluated based on the detennined kinetic model. The intensification of copper reduction in fire refining has been discusses on the basis of obtained kinetic data and analysis of various factors detennining the time of reduction.

Jan 1, 2003

By Hector Henao

To provide thermodynamic data for converting the nickel matte to liquid nickel, an experimental study was conducted in the phase equilibrium between the Ni-S alloy and the CaO-Al2O3 based slag melted in a MgO crucible at 1873 K under controlled Pso2 of 10.1 kPa and Po2 in a range between 2.5x 10-and 10.1 Pa by using CO-CO2-SO2 gas mixtures. The content of nickel in the slag at Po, of 10.1 Pa, above which solid NiO is expected to precipitate in the equilibrium state, was found to be 4, I mass% and the contents of sulfur and oxygen in the nickel melt were 0.4 and 02 mass%, respectively. ft was clarified that increase in the temperature reduces the solubility of nickel in the slag and the contents of sulfur and oxygen in the alloy, The distribution of minor elements such as gold, silver, copper, cobalt, iron, arsenic and antimony between the Ni-S alloy and the CaO-Al2O3 based slag was also studied. The distribution ratios of iron and cobalt, defined by (%X in slag)/[%X in alloy] where X is the minor element, are larger values than that of nickel, while those of copper, silver and antimony are similar to that of nickel. The distribution ratios of arsenic and gold are lower than that of nickel in the higher range of oxygen partial pressure.

Jan 1, 2003

By Gabriel Riveros

Fire refining of copper consists of two stages copper oxidation and copper reduction. Very frequently the capacity of the anode furnace is determined by the rate of copper reduction, The analysis of factors affecting the rate of the oxygen reduction from a liquid copper with solid carbon or injected hydrocarbons pointed out the role of the mass transfer in a liquid copper in final stage of the reduction. Experimental results of copper reduction with graphite and injected natural gas in laboratory-scale crucibles showed two stages of the reduction process with a sharp change of the controlling mechanism. The estimated dynamic surface area of gas bubbles based on the measured bubble frequency and the gas flowrate allowed for the determination of the reaction constant as a degree of the partial pre-combustion of the air/natural gas mix. The variation of the used reductant as a function of the oxygen concentration and temperature has been evaluated based on the determined kinetic model. The intensification of copper reduction in fire refining has been discusses on the basis of obtained kinetic data and analysis of various factors determining the time of reduction.

Jan 1, 2003

By K. G. F. Janssens

In the process of annealing a deformed metal the microstructure changes due to concurrent recrystallization, grain growth and precipitation. It is common knowledge that all three of these microstructural transformations show a strong dependence on each other, and that an overall model must take the relevant interactions into account. Aiming at the development of an approach which is useful in the more general case, a computational model is being developed which allows the prediction of the three dimensional grain topology and orientation distribution function of any metal submitted to subsequent deformation and annealing, taking into account concurrent recrystallization, grain growth and precipitation and starting from a statistical representation of the deformed microstructure. In this contribution a case study is presented which illustrates the potential and limits of the state of the art in the field. Keywords: Microstructure Evolution Modeling, Irregular Cellular Automata, Deformation, Precipitation, Recrystallization, Grain Growth

Jan 1, 2003

By R. C. Hubli

A chemical model has been developed to investigate the dissolution of sulphide minerals in brine solutions containing copper and iron chlorides. The model has been employed to study the dissolution .of synthetic NiS using different initial concentrations of Cu(II), Cu(I), Fe(III) and temperature. The speciation of copper with particular reference to the formation of hydroxy-chlorides as a function of total chloride and H+ has been computed. The model predictions are in agreement with experimental results. It has been found that addition of Fe(III) results in the maintenance of a high Cu(II)/Cu(I) ratio leading to enhanced rates of dissolution and suppresses the loss of Cu(II) due to the formation of hydroxyl-complexes.

Jan 1, 1997