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By Olexandr Gydin

The evolution of grain and dislocation structures during cold deformation of the new steel LH800 of Salzgitter AG is investigated in the frame of this work. The main feature of this material is its ability to air-harden by carbon content of about 0.1%. The initial ferrite structure of the metal provides high plasticity at cold deformation and subsequent heat treatment increases tensile strength approximately two times. Described are results of in-situ tensile tests in the SEM. SEM and TEM analysis of grain and dislocation structures evolution in samples, which have been uniaxially deformed to certain strains, are carried out. After statistical evaluation of results the grain elongation against strain is determined. A microstructure of a deep drawn cup is analyzed by means of SEM. A quantitative evaluation of grain elongation on the different cup zones and comparison of these data with prediction results based on tensile tests are carried out.

Jan 1, 2009

By Guiqing Zhang, Liansheng Xiao, Zuoying Cao, Li Zeng

A new process of direct solvent extraction of nickel from sulfuric acid leach solutions of low grade and complicated nickel resources using a novel extractant HBL110 was proposed. The basic performance of new organic system was investigated and the continuous pilot plant and the industrial test were conducted. The results indicated that the extractant of HBL110 can be used to directly extract nickel selectively over iron, aluminum, manganese, magnesium, calcium and chromium from sulfuric acid leach solutions. The loaded organic solution can be easily stripped using dilute H2SO4 solutions. Both kinetics of extraction and stripping of nickel were fast. The continuous pilot plant test with the sulfuric acid leach solution of laterite containing 6.22g/L Ni2+, 14.1g/L Fe3+, 0.73g/L Fe2+, 33.9g/L Mg2+, 1.58g/L Al3+, 0.495g/L Ca2+, 0.97g/L Mn2+ and 0.5g/L Cr3+ as feed in mixer-settlers showed that the process had run stably with 98% recovery of nickel. The concentration of nickel in strip liquors reached as high as 50 g/L while the removals of Fe3+, Fe2+, Mg2+, Al3+, Ca2+, Mn2+ and Cr3+ were 98.5%, 91.5%, 99.95%, 99.8%, 99.1%, 98.6% and 99.5%, respectively. The industrial test with the sulfuric acid leach solution of electroplating sludge containing 11.5g/L Ni2+, 2.68g/L Fe3+, 7.54g/L Cr3+, 0.61g/L Mg2+, 2.09g/L Al3+, 0.68g/L Ca2+, 0.022g/L Mn2+ and 0.154g/L SiO2 as feed in mixer-settlers also showed that the process had operated successfully with 99.5% recovery of nickel. The concentration of nickel in strip liquors reached 42.7 g/L while the removals of Fe3+, Cr3+, Mg2+, Al3+, Ca2+, Mn2+ and SiO2 were 99.2%, 99.77%, 99.73%, 99.56%, 99.57%, 98.51% and 98.75%, respectively. The new process exhibited big advantages of short flow sheet, high recovery of nickel, high removal of impurities, low chemical reagent consumption and low cost. Application of this process in industry is expected to make important impact on the extraction of nickel from sulfuric acid leach solutions and to deliver good environmental and economical benefits.

Jan 1, 2016

By Guo Chen, Jin Chen, Jinhui Peng

In this paper, solving common problem of electrostatic precipitator (ESP), which was frequently ruptured of the cathode insulation in the production process were studied. The microwave heating airflow technology was introduced, which takes full advantage of its unique properties, solves the output problem of the high temperature air, achieves purpose of energy conservation, important economic significance and environmental significance. The mathematical models and designing of microwave high-temperature hot air system was calculated. The common forms of heat exchangers and comparative analysis were also introduced. The conditions found to be at the temperature of 240 °C. Under optimum conditions, the microwave heating power was 1482 W. Based on the mention results, this microwave heating method can be applied effectively and efficiently way for the production process of electrostatic precipitator.

Jan 1, 2015

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 Mark Cross, Diane McBride, Nick Croft

Extractive metallurgical processes rate amongst the most complex from the perspective of computational modeling. They typically involve multi-phase and multi-component fluid flow in very complex geometries, heat transfer driven by a number of interacting phenomena, solidliquid- gaseous phase change and mass transfer together with complex thermodynamics and associated chemical reactions. Beyond the model building itself, key challenges have always involved being able to identify the phenomena present together with interactions to characterize processes and experimental laboratory and plant data to parameterize the arising models – it is in this milieu, which require considerable process understanding and subtlety of thought, that David Robertson has made his contributions. We will review the achievements, over the last couple of decades, in computational modeling of extractive metallurgical processes and address some of the remaining challenges to enable simulation based process design, as we move through the 21st century.

Jan 1, 2014

By Ehsan Khajeh

In this study, the permeabilities of Al-15.5wt%Cu and Al-19.5wt%Cu have been determined by solving the full Navier-Stokes equations on 3D geometries of interdendritic channels obtained by X-ray microtomography (XMT). The samples for XMT were sectioned from different positions in directionally solidified cylinders in order to obtain a variety of microstructures for each composition. The flow has been solved using a 2nd-order accurate Finite Volume Method (FVM) approach. The effect of employing uniform or unstructured mesh on the calculated permeability has been studied. The Marching-cube triangulation method was necessary to extract accurate surfaces for unstructured volume meshing. Calculated values of permeability for this range of solid fractions show partial agreement with previous experiments. Observed deviations are attributed to the difficulties of experimental permeability measurements.

Jan 1, 2009

By Zhaohui Xie, Bin Xu, Qian Li, Yongbin Yang, Tao Jiang

A high carbon low-grade gold ore, in which gold mainly occurs in carbonaceous matters, is a typical refractory gold ore whose conventional cyanide leaching extraction is only 12.9 %. In this paper, by the process of flotation-roasting-leaching, gold was effectively enriched and extracted. The flotation results showed that the enrichment ratio of gold was relevant to that of carbon, indicating that gold occurred in close association with carbon. A concentrate containing gold 7.26 g/t and carbon 12.37 % was obtained, with gold recovery 83.10 % and carbon recovery 90.24 %. Subsequently, the roasting of flotation concentrate favorably made the removal rates of carbon and sulfur reach 99.81% and 98.79%, respectively. After roasting, the gold in the roasted product was further enriched to 29.70 g/t and the optimal gold cyanide leaching extraction reached 93.66%.

Jan 1, 2015

By Jianxun Song, Hongmin Zhu, Qiuyu Wang, Jungang Hou, Shuqiang Jiao, Xiaobo Zhu

This work presents the results of a study on the Ti3+/Ti2+ couple redox potentials vs. Cl–/Cl2 at the temperature range (673 to 1073 K) in fused LiCl-KCl eutectic by direct potentiometric method. Initial concentrations of TiClx in solvents did not exceed 5.0 mol%. Basic thermodynamic properties of the reactions TiCl2+1/2Cl2(g)=TiCl3 were calculated using the temperature dependencies of apparent standard potentials of the couples E* Ti3+ /Ti2+.

Jan 1, 2014

By Liang Wang, Sheng-Kai An, Bing Xie, Hong-Yi Li, Cui Li

In order to develop an environment-friendly method for extracting vanadium effectively from aqueous solution containing vanadium, the dynamic adsorption behavior of V by a continuous fixed-bed column which was filled with macro-porous weak base anion exchange resin was studied. Effects of conditions including the bed depth, flow rate, concentration of vanadium ions on dynamic V adsorption were investigated. The optimum adsorption conditions were established at flow rate of 6 ml/min with bed depth of 20 cm. Isotherms studies demonstrated that the column adsorption of V was a favorable chemical ion exchange process in monolayer. Several kinetic models were applied to analyze the adsorption characteristics. Analysis results of the Bohart-Adams model indicated that the adsorption process was dominated by external mass transfer in the initial stage. The Thomas model was appropriate to describe the column behavior, revealing that both external and internal diffusions were involved in the limiting steps.

Jan 1, 2014

By Charles Washburn

The authors review mercury sources, and contaminant streams, with particular emphasis on mercury that is extracted from precious metal ores. The design and operation of both large and small mercury distillation facilities are detailed. The relevant properties and characteristics of mercury and mercury vapor are presented. Facility engineering with respect to industrial hygiene, area ventilation, and material handling is presented.

Jan 1, 2003

By Ryokichi Shimpo, Akio Fuwa

"In order to elucidate the present status of process-control technology, survey study has been made on the present process control schemes of representative copper smelting and converting processes in Japan. Conceptual control flow diagrams have been deduced and shown on respective functional reactors, i.e. drying, smelting, converting and fire-refining units, where the objective OUTPUT items are correlated to the INPUT variables through respective CAUSE-AND-EFFECT RELATIONSHIPSFuture view has been also discussed on several feasible and desirable improvement and refinement ~n measurements and control system for better copper smelting and converting operations.INTRODUCTIONIn other to seek for the better and efficient operation in copper smelting and converting process, survey study has been first conducted on the present process-control schemes of respective functional unit processes, i.e. drying, smelting, converting and refining unit processes, of representative copper production processes in Japan. Conceptual process flow chart of control scheme has been then deduced where output items are correlated to input items through the respective cause-and-effect relationships.After this survey study, future view has been discussed on the feasible and desirable improvement and refinement in the measurement and control system in these processes. Emphasis has been placed on the better and precise measurements of temperature, oxygen partial pressures in respective furnaces and end-point in converting and refining unit operations."

Jan 1, 1989

By M. C. Flemings, S. B. Brown

"Metallurgy, as all of material science and engineering, rests on the intellectual foundations of processing-structure-property-performance relationships. Today it is widely recognized that processing has been too long neglected and presents exciting opportunities for exploitation. New processes, many of them already in the laboratory, will be exploited in the year 2000 and beyond, for near net shape forming and for achieving-new metallurgical structures and composite structures. Process modelling will alter the way we think about process and product design. Processes themselves will increasingly be automated and controlled by computers, altering the nature of the workplace and the tasks of the metallurgical engineer of the future. IntroductionInnovations in metal processing is hardly a new phenomenon, with the field thousands of years old. Nonetheless, the next few decades offer particularly important opportunities to improve our ability to process these materials. We appreciate today the variety of processing paths available to us, including vapor-, plasma- and electro-deposition, multiple phase and casting technologies, and non-equilibrium processes, and how these affect structure at the atomic level and at higher levels of aggregation. We understand the basic physical mechanisms involved far better than even before and have remarkable new abilities to predict, control, and simulate the kinetics underlying processes, and the processes themselves.The following sections describe these new opportunities in greater detail. First, we examine developments in the modelling of metal processing. We then consider some implications associated with process control and automation. Finally we present what we consider to be particularly promising metal processing technologies, and conclude with a few summary comments."

Jan 1, 1988

By Ragnhild Aune

In fire refining of copper, the affinities of various impurity elements on dissolved oxygen is of great significance. Further, in the design of oxygen probes in liquid copper, the influence of solute interactions on the activity of oxygen need to be considered in order to evaluate the oxygen concentration in molten copper. The present paper presents a series of measurements of the activities of oxygen in liquid Cu-M-o alloys (where M stands for Mn, Zn, As, Se or Te) carried out by the present group employing the solid electrolyte galvanic cell technique. Extreme care was taken to control the oxygen potentials in the inert gas atmosphere, and to keep the oxygen levels very low in the molten metal. The oxygen content was determined by analysis of the samples taken out from the melt. The results obtained showed that Mn has a strong negative influence on the activity coefficient of oxygen in liquid copper. A similar, but less prominent effect was observed in the case of Zn. Arsenic had no influence on the activity of oxygen in Cu (liq.). Se and Te had slight negative effect on oxygen activities in copper at XO > 10-5, while at lower oxygen levels the interaction coefficients were found to be positive. The results obtained were compared with empirical models for the calculation of interaction coefficients available in literature.

Jan 1, 2003

By James R. Craig

The General Image Processing System (GIPSY) is being employed for the quantitative textural analysis of complex sulfide ores from the Southern and Central Appalachians and for the determination of liberation characteristics of the mineral constituents during grinding. Optical images from a microscope-mounted TV camera or from 35mm film are converted into digital images which are subsequently analyzed by GIPSY, a transportable image processing software package. Properties measured by GIPSY include spatial distribution of mineral constituents, grain sizes, grain shapes, grain orientation and mineral co-occurrences.

Jan 1, 1982

By Moto Goto

Today, Pierce-Smith converters, coupled together with various types of smelting units, are used in most of the world's smelters, However, due to the "batch" processing nature, and problems associated with fugitive emissions during the transfer of melt and blowing stages, this arrangement will unlikely be adopted in future smelters. Modern day alternative processes include the Mitsubishi Process, Outokumpu Flash Smelting and Flash Converting Process, the Noranda Process, and the Ausmelt Process, but only the Mitsubishi Process is a "truly continuous" smelting and converting operation, producing a constant flow of blister without tapping, and is economically proven by long term commercial operations. This paper reviews recent advances in modern continuous converting technologies, with a special section devoted to operation of the "first standalone Mitsubishi C-furnace" coupled together with a Noranda Reactor, at Port Kembla Copper Pty, Ltd. in Australia.

Jan 1, 2003

By Andres Vikdahl

The Rönnsktär smelter has recently undergone a series of technical and operational changes. This changes are caused by our own will to remain and gain in competivety and to adapt to the ever changing surroundings. To be able to remain competitive in surrounding with high wage costs, high inflation and high environmental standards thorough cost management is needed. The Swedish economic policy in the beginning of the 80'ies consisted amongst other things of two devaluations. The exchange rate of the Swedish Krona was reduced with approximatively 25 %. This boosted the profits of our export industry, some even believed we entered the land of milk and honey ... And working in this promised land where everything turns into profit it is very difficult to be careful and restrictive with your spendings. Apart from some healthy and fruitful investments we allowed ourselves yearly steady increases in salary for ever reduced number of worked hours and we of course employed more people. Inflation rates went up and so did property prices. In 1986 finally reality catched up on us. Reality in the form of too high costs started to hit Swedish export industry 5-6 years after the big devaluations. Furthermore the high inflation rate also hit the domestic industry a couple of years later. Together with other important factors Sweden faced a severe home-made recession in the beginning of the 90'ies. With this background we now report and analyse our smelter's performance and operating results, shown in fig 1 The main constrictions on smelting and refining at Rönnsktär are today: * Income restrictions by governmental production level Limit * Throughput resmctions by governmental emission limit * High capital costs in the aftermath of Swedish high inflation in the recent decade * Low work force turnover Below we will illustrate how we tackled with these issues along the following lines: * People * Quality * Technology

Jan 1, 1993

By Varadarajan Seshadri

The performance of mould fluxes in satisfying its quality requirements can have a significant effect on the efficiency of the continuous casting process and on the surface quality of the products. This performance is affected by various parameters including the characteristics of the mould fluxes, the quality of the steel being cast and the operational conditions of the caster. The extremely complex relationships involving the parameters mentioned above make it very difficult to have simple criteria for selecting mould fluxes for casting a certain grade of steel in a continuous casting machine. These difficulties led steelmakers and mould flux suppliers to select mould fluxes based mainly on plant trials. In the present work, a software to help in the analysis and development of mould fluxes for continuous casting was developed. This software includes several models for prediction of mould flux viscosity and consumption. A mathematical model was also used to predict the heat flux through the mould flux. The proposed methodology was applied to continuous casting of crack sensitive steels. Some of the results given by this software are presented, discussed and compared to plant data.

Jan 1, 2003

By Andreas Orth

Outokumpu Lurgi Metallurgie has developed a process for the calcination and reduction of laterite nickel ore tines where the reduction of iron and nickel to the wustite/metallic states respectively, is performed in a fluidized bed reactor using reduction gas generated very cost effectively from natural gas in an autothermal catalytic reactor. As an option coal can be used as reductant as well as additional fuel. The process of reduction and calcination is very energy optimized. It uses the off gas from the fluidized bed reduction reactor, which still contains energy, to dry and calcine the nickel ore fines in a primary stage circulating fluidized bed (CFB) reactor. The product shows high metallisation of nickel and iron oxides reduced to the wustite stage. This results in considerable energy savings in smelting the prereduced product to ferro-nickel. Alternatively the product can be leached to produce nickel. Laboratory tests showed very high recovery of nickel and cobalt. Keywords: Fluidized Bed, Prereduction, Calcination, Ferro-Nickel

Jan 1, 2004

By Steven I. Baskin

Cyanides are utilized in many industrial applications including preparation of chemical intermediates, electroplating, and' mining, Cyanide has been utilized in chemical warfare operations as well Cyanide is also synthesized and found in plants and animals including man where it is thought to perform multiple functions. A variety of enzymes are known to detoxify cyanide under different conditions. These include rhodanese, 3-mercaptopyruvate-sulfur transferase, thiosulfate reductase, cystathionaseand albumin. Cyanide appears tQ exert its toxic effect primarily by inhibiting cytochrome oxidase? although other enzymes are also inhibited. Therapeutic antagonist categories to treat cyanide include methemoglobin formers such as nitrite, sulfane-sulfur donors such as thiosulfate, metal salts or complexes such as cobalt and cyanohydrin-forming compounds such as dihydroxyacetone or alpha keto-glutaric acid. Advantages and disadvantages of each category will be discussed. Newer compounds under development have been found that may allow for prophylactic therapy for cyanide poisoning with minimal side effects; In addition, portable co-oximetry devices may provide real-time measurement of cyanide in field units.

Jan 1, 1998

By E. Anelli

Based on experimental continuous cooling transformation (CCT) diagrams, an artificial neural network has been trained to predict the amount of microsturctural constituents and hardness resulting from and controlled cooling at rates from 150 to 0.015 K/s. It can be applied to quenching and normalizing processes of low-alloy steels with 0.05-0.30 C% and 0.4-2.0% Mn -with possible microalloying additions. Examples of the good predictive capabilities about 15 Vickers standard deviation for hardness and a few percent for volume fraction of phases) are reported' Keywords: Austenite decomposition, low. And medium-carbon steels, artificial neural networks

Jan 1, 2003