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By T. M. Dreher

The difficulties associated with the operation of a classical rhodium refining process have prompted many attempts to develop a viable solvent extraction flowsheet for rhodium. Recent investigations at McGill University have involved the activation of rhodium prior to its solvent extraction. The role of activation is to convert the aquochloro complexes of rhodium to a form extractable by conventional solvent extraction reagents. In the novel separation scheme identified, chloro complexes of rhodium are converted to bromo complexes, which undergo aquation to a lesser extent, making them more easily extracted. Rhodium is then extracted using Kelex 100, and stripping is achieved by use of a concentrated chloride based solution. Separation of rhodium from iridium is achieved by either prior reduction of Ir(IV) to Ir(III), as the latter is not extracted, or via co-extraction and differential stripping. A conceptual flowsheet for the refining of rhodium using this method is proposed.

Jan 1, 1998

During electrowinning of nickel chloride, hydrochloric acid was regenerated instead of chlorine in a two membrane cell, by segregating the chloride catholyte with an anion exchange membrane, and the sulphate anolyte with a cation exchange membrane from the middle electrolyte (ampholyte) compartment. Successful operation of such a cell depends on controlling chloride leakage through the cation exchange membrane to the anolyte. Small amounts of chlorine gas could be detected in the oxygen evolved at the anode. In this paper, the chloride. leakage as a function of various types of cation exchange membrane and different composition of the anolyte is reported and discussed. Ag+ was added to the anolyte to eliminate chloride leakage to the anode. The cell voltage, electrode potential and voltage drop over the membrane as a function of current density has also been investigated.

Jan 1, 1996

By Kai Hu, Xuewei Lv, Run Zhang

An oxygen sensor of zirconia-based solid electrolytes for in situ measurements of oxygen potential in high titanium slag was developed in the present study. With the facility, series of measurements of electromotive force were successfully conducted for different titanium slags at 1998 K under an argon atmosphere. Oxygen potential in the slag was calculated by the measured EMF and simultaneous readings of temperature using the modified Nernst equation. In addition, the relationship between slag compositions and the oxygen potential in the slag was explored in detail. It has been found that the oxygen potential increases with increasing FeO content in the slag and decreases with the increasing Ti2O3 content in the slag. The oxygen potential in the slag has been calculated thermodynamically and compared with the experimental measurements. The results showed that oxygen potential in the slag may be controlled by FeO/Fe equilibrium reaction.

Mar 1, 2018

By Z. B. Moukhametshina

The process of various zirconium alloys iodination by the iodine vapor was investigated. The nature of impurities, conditions of iodination, iodine flow rate, and zirconium tetraiodide condensation rate effect on the metal impurities transfer process was analyzed, both qualitative and quantitative correlations were established. Impurities were classified according their transfer extent. Another classification of impurities transport dependence on iodination process temperature was also offered. Obtained results were compared with impurities transport data in the process of iodide refining available in literature. Some impurities transport mechanisins and iodide-refined metals improvement possibility by means of iodination conditions control were discussed.

Jan 1, 1997

By Markku Rytkonen, Shaolong Chen, Ilpo Kylmäkorpi, Hannu Mansikkaviita

Though the Peirce Smith (P-S) converter is a traditional type of furnace, continuous improvement in its mechanical and electrical design is still Kumera's approach. Efforts are made particularly on the following aspects: converter head shape for easy fabrication and structural strengthening, oxidation air swivel joint for low pressure drop and low noise level, wind box for even air distribution to tuyeres, drive unit and its control for reliable and handy operation. These improvements have successfully been applied in recent P-S converter deliveries.

Jan 1, 2009

By Weizhi Zeng, Michael L. Free, Shijie Wang

Copper electrorefining is an old technique that is generally performed in electrolytic cells with a bottom inlet and top outlet that are convenient for electrolyte flow control. Nevertheless, this configuration cannot effectively direct electrolyte flow to the regions between electrodes, which results in weak convection and inadequate delivery of chemical species and additives. In this article, we discuss the innovations in electrore fining cell design to improve electrolyte flow for better cathode quality and simulation of fluid flow field and particle movements based on finite element modeling method. The resulting fluid flows in cells can transport suspended slime particles to the cathode, where they can be incorporated as impurities. The concentration of suspended slime particles is inversely related to slime adhesion, which is strongly influenced by slime particle sintering, and sintering is dependent on temperature and slime particle composition. Thus, the combination of innovative fluid flow and slime particle sintering can play important roles in improving cathode quality.

Mar 1, 2017

By Jie Li, Wenzhou Yu, Xuewei Lv

An efficient enrichment of primary silicon from the Al–Si melt can be beneficial for the Si purification and the cost reduction of the solvent refining process. In this paper, an alternating magnetic field was used to enhance the mass transfer and promote the crystal growth of primary silicon during the directional solidification of hypereutectic Al–Si alloy. The results show that the growth rate and morphologies of Si crystals changed continuously along the directional solidification direction. With the decreasing of Si content in the melt and the weakness of the electromagnetic stirring, the crystal growth rate of primary silicon gradually decreased and the Si morphologies changed from planetocellular ,cellulardendrite, and columnardendrite, respectively. This provides a deeper understanding of the Si crystal growth during the electromagnetic solidification, which will be good for achieving a high-efficiency enrichment of primary silicon in Al–Si melt.

Mar 1, 2018

By Wenjun Duan, Zhimei Wang, Tianwei Wu, Qingbo Yu

In order to recover the waste heat of molten blast furnace slag, a reactor with top-submerged lance was established. The numerical simulation and experiment study of the flow characteristic in the reactor were conducted. The mathematical model of reactor was established and the Euler-Euler model was employed to simulate the gas-liquid flow in molten slag bath. Meanwhile, the experiment results were obtained and compared with the simulation to testify the accuracy of the established model. According to the bubble behavior in bath, there were four stages: initial expansion stage, bubble detachment stage, freedom lift up stage and bubble broken stage. When the flow field in bath fully developed, the gas fraction decreased with the increasing of bath depth. During injection process, the area near the nozzle and lower the bath would first generate two symmetric heliciform flow regime, and then the flow regime in whole bath would become irregular because of bubble lifting up and rupturing. The gas fraction in bath, the average velocity and turbulence energy of slag would decrease before it increased to maximum and then it would keep fluctuate in a range.

Mar 1, 2018

By Mairyanne S. S. Souza, Sergio Neves Monteiro, Victor Tomazinho Bartolazzi, Dienifer Daiana Konzen

Clay is used in the production and manufacture of materials for the construction of buildings from remote periods. Advances and improvements of its properties have allowed several applications to this raw material. In this work the quality of four types of ceramic tiles manufactured or used in the northwest of the state of Rio de Janeiro and in the southeastern state of Minas Gerais was evaluated. Geometric, physical and mechanical aspects were evaluated according to the Brazilian standard NBR 15310:2009. The results indicate numerous nonconfor- mities with highlights for geometric parameters, surface flatness and yield tests. The nonconformities found in the samples indicate that there was a failure in the production control of the product and in the approval of the control of the lots.

Mar 1, 2018

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 Jingtao Wang, Xiaoyu Han, Jun Bao, Wei Hou

Lightweight stainless steel has widely potential applications in many fields, such as automobile, ship, submarine manufacturing and aerospace. The properties of lightweight stainless steel are significantly affected by the precipitating behaviour of second phase particles. In this paper, the precipitating behaviour was investigated by XRD, DSC in the process of heating and thermodynamic calculation combining the Miedema’s and Chou’s model. The XRD results indicate that there are five types of phases in lightweight Fe–Mn–Al–C–N stainless steel: ferrite, FeAl, AlMn, AlN and Mn4N. The DSC results show that the precipitating temperature of FeAl, Mn4N is 1260, 1031 °C, respectively, corresponding to the thermodynamic calculation. Besides, The DSC measurement reflects the precipitating temperature of AlMn and austenite is 934 and 600 °C.

Mar 1, 2018

By Wen-long Zhan, Zhe Ning, Jun-hong Zhang, Teng-fei SONG, Zhi-jun He, Qing-hai Pang

In order to investigate the influence of granularity on the gasification property of coke after microwave irradiation, comparison of ordering of carbon structure and internal microstructure of granular coke before and after microwave pretreatment was carried out. It is shown in X-ray diffraction results that the diffraction intensity of the coke sample significantly increased after 40 s irradiation under 264 W microwave power, which indicated the decrease in reactivity of coke.

Mar 1, 2017

By Peter Stiaszny, Andrej Samoilov, Yuri Titovets, Gottfried Hribernig, Nikolai Zolotorevskii

"The model has been developed to simultaneously predict both transformation product portions and mean ferrite grain size from the same common · principles as a result of the austenite decomposition during any cooling path of dual phase steels. The transformation products considered are polygonal ferrite, pearlite, bainite and martensite. The model is based on the classical equations of nucleation-growth theory and also contains some empirical parameters. The chemical driving forces for nucleation and composition of elements at the phase interfaces are derived by computation thermodynamics. The empirical parameters related to the model were determined on the basis of a series of austenite transformation dilatometric curves and grain size measurements for continuous and interrupted cooling of several steel types. The model is aimed to predict phase transformation in the complex cooling conditions of the run-out table of the hot strip mill at YOEST-ALPINE STAHL LINZ GmbH as a part of the computer aided system for prediction and on-line controlling of the mechanical properties of hot-rolled strip.IntroductionThe term ""dual phase steels"" is used to refer to a steel consisting essentially of a dispersion of martensite in a fine-grained ferrite matrix. These steels are of increasing technological interest since they provide a better combination of strength and ductility than any other conventional steel sheet material. The strength is important because it offers an opportunity to produce lighter components, while good ductility is needed to permit easy forming of components. It is generally recognized that martensite plays an important role in determining the strength level of dual phase steels. A full understanding of the role played by the phases in determining such characteristics requires investigating in more detail how to optimize the martensite level of such steels, while maintaining good ductility remains the subject of continued research in the industry."

Jan 1, 2000

By Junwei Han, Wenqing Qin, Dawei Wang, Fen Jiao, Wei Liu

The removal of iron impurity from zinc calcine was studied by magnetization roasting and magnetic separation. The effects of roasting temperature, magnetic intensity, ore grinding, and leaching pretreatment on iron grade and recovery were investigated. The results indicated that iron recovery increased with the increase of roasting temperature or magnetic intensity, while iron grade was always less than 22%, depending on the fact that the magnetite were not liberated completely. The good liberation was difficult to be achieved by ore grinding but was easier by acid leaching, since the magnetite grains were very fine. After the leaching pretreatment, the recovery of 76.31% with iron grade of 53.24% was obtained by one roughing and cleaning. The SEM/EDS analysis showed that a part of sphalerite, zinc ferrite and other gangues were mixed into the iron concentrate, while some of fine magnetite was reported to the tailing.

Jan 1, 2016

By Y. Pokhvisnev, S. Vandariev, A. Yatshenko-Juk, V. Valavin, V. Romenets

The technology of the liquid-phase reduction process known as Romelt was developed in the Moscow Institute of Steel and Alloys in 1979. The pilot plant was constructed at the Novolipetsky Steel Works (Russia) in 1984. Investigations into processing zinc-containing blast oxygen furnace dust and slag from the Lead and Zinc Works at the pilot Romelt plant proved the perspective of using this technology for processing zinc and lead-containing materials. In this article, the description of Romelt technology, basic technological information of trials at the Romelt plant using zinc-containing materials, compositions of charging materials, metal, slag, gas and dust are presented. The influence of flue gas composition on the composition of zinccontaining dust is shown.

Jan 1, 2000

By Zhi-xiang Cui

Dongying Fangyuan Nonferrous Metals Co., Ltd. has developed a new technology to produce anode copper from concentrates through only two furnaces. This new technology is called the Two-Step Copper Smelting Process. This paper presents the commercial application of the Two-Step Copper Smelting Process and its operating conditions. The key features of the Fangyuan Two-Step Process are as follows: (1) feed materials, including concentrates and flux, are mixed without pretreatment and fed into the Submerged Lance Smelting (SLS) furnace; (2) high grade white metal (WM) produced by the SLS furnace is transferred via WM conduit into one of the two Submerged Lance Converting and Refining (SLCR) furnaces; and (3) the two SLCR furnaces blow alternatively to maintain continuous operation of the whole production chain. The new smelter started operation in October 2015 with a processing design capacity of 1.75 Mt/year of mixed feed and has been operating for over 30 months.

By Mohamed Y. Bakr, Aly M. Abdel-Rehim

The present work is related with mechanical activation of processing of Egyptian wolframite by simultaneous ball-milling and pressure alkaline leaching, to improve the recovery of tungsten from wolframite. The results show a total recovery of tungsten from wolframite (97.8- 98.7%) by simultaneous ball–milling and alkaline leaching at temperature 175-200oC. It is concluded that processing of wolframite by simultaneous ball- milling and leaching is mechanically activated and accelerated as a result of the grinding action of steel balls that caused the immediate rupture by continuous removing the product layer of the reaction ( sodium tungstate and iron and manganese hydroxides ) from reacting particle surfaces. This leads to the exposing of fresh and activated wolframite particle surfaces to alkaline leach solution and consequently the acceleration of the reaction of wolframite leaching .The results of the kinetic study 0f alkaline processing of wolframite and its mechanical activation show that the system is under kinetic control.

Jan 1, 2015

By Jun Li, Lingling Zhang, Daqiang Cang, Guizhou Zhao

Pilot trial of direct modification of molten blast furnace slag and production of high acidity coefficient slag wool fibers were investigated nearby a blast furnace. Molten blast furnace slag discharged from blast furnace and then directly flow into specialized modification furnace and quartz was simultaneously added into the molten slag as modification agent. The modified molten slag was electric heated to 1500–1550 °C and then the melt was produced into slag wool fibers through high-speed centrifugation method. Melt with acidity coefficient of 1.2, 1.4, 1.6 and 1.8 were investigated and fibers with corresponding acidity coefficient were produced. Slag wool fibers with shot content of 5.5, 5.8, 6.2, 6.8% and average diameter of 4.5, 4.9, 5.6, 6.4 lm for four samples were successfully produced, respectively. Total energy consumption and production costs decreased by 50–70% compared to traditional cupola furnace method. This method provides an energy-saving and emission-reduction technology for the direct utilization of molten blast furnace slag.

Mar 1, 2018

By I. J. Moon

The reduction behavior of hematite by H2 and H2-CO gas mixtures was investigated to elucidate the reduction mechanism at 800-950 °C. The hematite compacts were made by Cold Isostatic Pressing to produce compacts of uniform shape and size. The compacts were sintered at 1000° C for 30min, and showed a contraction of 29%. Mercury pressure porosimeter was used for measuring the total porosity, pore size distribution and pore surface area of the compacts. Reduction was measured by means of weight-loss technique using Cahn Balance (Model : TG-171, capacity log, accuracy f 10pg). Microscopic examination and X-ray analysis were used to correlate the structure of reduced compacts with the mechanisms of reduction. Neither chemical reaction control nor diffusion control is adequate in describing the complete course of reduction of the hematite compact. The reduction of hematite compacts was initially controlled by the chemical reaction at oxidelmetal interface. The reaction goes through a transition phase .where it is undergoing a mixed control, followed by the diffusion control towards the end of the reduction. The values of apparent activation energies for chemical reaction control were 3.48-8.43 kcal/mol depending on the gas compositions.

Jan 1, 1997

By Thomas Boundy, PATRICK TAYLOR

Indium recovery from liquid crystal display (LCD) waste has been the subject of over 50 peer reviewed publications over the last decade; however, the first commercial recycling facilities are just beginning to be built. The low value of indium in the LCD screen material has posed a major challenge to would-be recyclers. Uncommon material combinations and geometries have further challenged development. A review of published literature regarding extraction of indium from LCDs will be presented and themes of advantageous processes will be highlighted. Barriers to rapid expansion of any recycling technology in the form of manufacturin gpractices, environmental regulations, and geographic constraints will be discussed.

Mar 1, 2018