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By Edgar Peek

Lixiviant regeneration is by definition a precondition for any hydrometallurgical process. In chloride hydrometallurgy either HCl or Cl2 has to be regenerated in order to establish an economically viable metallurgical process. One such regeneration process is widely used with steel pickling where HC1 is regenerated through the thermal decomposition of ferrous chloride in either spray roasters or fluid bed pyrohydrolyzers. This standard HC1 regeneration process deserves to be considered as a potential separation process, since thermodynamic calculations show that a fluid bed pyrohydrolyzer can function as a ferrous-nonferrous separator. Several nonferrous,metals such as zinc, lead and cadmium can be volatilized as a chloride under ferrous chloride pyrohydrolysis conditions. If such a nonferrous metal volatilization could be achieved in the case of slurry feeding of "contaminated" iron oxides, then this would increase the Fe/H2O ratio of the (process) feed and thus save on fuel per ton of iron, while yielding a marketable iron oxide product. Previous test work on synthetic materials revealed that the near-complete separation of zinc, lead and cadmium from iron oxide was possible in a pyrohydrolytic atmosphere, even if zinc was present as zinc ferrite (more than 99.5%). This investigation, which was carried out in a tube furnace at 1100 K has now been extended to treat synthetic zinc minerals and also franklinite ore. For the latter, it was found that 85% zinc volatilization could be achieved in 4 hours at 1300 K. It is postulated that complete zinc volatilization could not be attained due to the formation and/or presence of gahnite and hardystonite, which might be stable in HCl/H2O atmospheres at 1100 K. The effect of adding small amounts of calcium chloride to react with gahnite and hardystonite to give zinc chloride and both calcium aluminates and silicates is being discussed. Test work on slurry feeding of this complex ore in a recently constructed 4-inch diameter fluid bed pilot unit has been planned for the near future.

Jan 1, 1995

By Aarne Kopanen

In recent years, various renovations have been carried out in the production chain of the Outokumpu copper refinirg process. The anode casting shop, which is the final integral production section at the Harjavalta copper smelter built in its original form in 1945, was fourxl unsuitable for technical and capacity demads during longer periods of operation, and a new casting shop was built in 1974. The electrolytic copper refinery of Outokumpu Oy at Pori was built in 1941, and subsequently expanded in two stages. Even with its present limited scale of production it has been fom important to mechanize the main operations. This work was started in 1967 with the design and construction of the starting sheet machine connected with the cathode washing and unloading machine as a combined unit. Mechanized treatment of anodes has gained advantage particularly from the new design of a highly automated anode casting shop. In the further development of the mechanization a stripping machine for, starting sheets was designed and installed, starting operation in 1974.

Jan 1, 1976

By Ji-He Wei

The ESR of Cu-Cr-Zr alloy has been experimentally investigated. The remelting experiments have been carried out with different slag fluxes in the Cal, + Nal, CaF2 + ZrO2 and CaF2 + NaF + ZrO2 systems on an ESR furnace of 25kg capacity; using a water-cooled copper mould of 96.5 mm diameter, with the forged square bar electrodes of 50x50 mm2. The slag amount was taken to be 1.5 kg. The remelting current and voltage used were 1600-1800A and !5-25K, respectively. The influence of the slag composition on the stability of the remelting process and the losses of alloying elements (2r and Cr) has been considered and examined. The technologies of hot working and heat treatment of the ES ingot have been described and discussed. Some physical properties of the slag in a CuF2 + NaF + ZrO2 system and the remelted Cu-Cr-Zr alloy have been determined. The results indicated that with the slag flux of CaF2 + NaF + l0 mass % ZrO2 and the other operation parameters employed, a high quality ingot of Cu-Cr-Zr alloy may be obtained at the considerably high yields of Zr and Cr by means of ESR. For the remelted Cu-Cr-Zr alloy with a specified composition of 0.5 mass % Cr and 0.1 mass % Zr, the appropriate electrical conductivity, hardness and softening temperature are as high as 45-46S/m, HRB 82-84 and 550°C. respectively. The properties of the Cu-Cr-Zr alloy products are in accordance with and superior to the requirements and specifications of ISO5l82-l99l(E).

Jan 1, 2000

By Varuzan Kevorkijan

A new method for faster production of functionally graded metal-ceramic laminates is based on reactive pressureless counterflow infiltration/penetration of a ceramic substrate with two different metallic infiltrants. The porous or dense ceramic preform is pressurelessly infiltrated or penetrated from one side by the first metallic infiltrant to the desired cross section of the preform, producing the top layer made up of the solidified infiltrant and the underlayer consisting of reactive infiltrated preform. The partly infiltrated preform is then completely infiltrated starting from the other side by the second metallic infiltrant, in this way fabricating the internal layer, consisting of the ceramic preform infiltrated with the second infiltrant and the bottom layer formed by the solidified second infiltrant. Systems already investigated include carbide, nitride and boride ceramic performs infiltrated with aluminum and magnesium alloys.

Jan 1, 2003

By Z. W. Zhang, Songsong Xu, Jinhui Li, Yun Zou, Yu Zhao

High strength low alloy (HSLA) steels with high strength, high toughness, good corrosion resistance and weldability, can be widely used in shipbuilding, automobile, construction, bridging industry, etc. The microstructure evolution and mechanical properties can be influenced by thermomechanical processing. In this study, themomechanical processing is optimized to control the matrix microstructure and nano-scale precipitates in the matrix simultaneously. It is found that the low-temperature toughness and ductility of the steels are significantly the matrix microstructure during enhancing the strength by introducing the nano-scale precipitates. The effects of alloying elements on the microstructure evolution and nano-scale precipitation are also discussed.

Jan 1, 2016

By V. Blet

Rare earth elements (REE) are regarded today as highly critical raw materials but currently lack suitable recycling processes. A combined hydro- and pyrometallurgical process aimed at REE recovery from used NdFeB permanent magnets was recently developed by the CEA. The process integrates the physico-chemical treatment of magnets, followed by a solvent extraction step for the recovery and intra-REE separation using a selective extractant. A subsequent pyrometallurgical treatment via molten chloride salt electrolysis allowed the isolation of pure Dy metal. Technical-economic assessment and life-cycle analysis were also conducted. Following this first successful demonstration, a new project aimed at the recovery of REE from end-of-life nickel-metal-hydride batteries is currently being developed in association with industrial and academic partners. The project aims at evaluating from an experimental and economic perspective different processes converging at the production of value-added products such as cermet materials for catalytic applications, purified REO concentrates, or metallic alloys.

By Wang Shuchan, Zhang Zimu, Zhang Dianhua, Liu Yan, Zhang Ting-an, Zhao Qiuyue, Lv Chao

Rare earth extraction tank has many adverse effects like big floor space and high production accumulation during industrial production. Current researches usually focus on changing the device structure without making a breakthrough towards gravity clarification. This paper attempts to achieve this goal by using both the action of clarification by gravity and clarification by stirring. Because many physical parameters affect the clarification and separation rates, the density, viscosity and surface tension of the two phases were determined at different temperatures and different concentration of aqueous solution. The innovation of this research involves adopting the Karl-Fischer method to investigate water content in oil phase during the stirred separation process. In this paper, the separation effect of different physical parameters was studied and the dimensional equation between water content and the physical parameters was established by combining with the experimental data.

Jan 1, 2014

By A. G. Cecutti

A brief overview of the known significant health effects of both Nickel and Cobalt will be presented. Some time will be given to the current research activities, especially for Nickel. Emphasis will be placed on some of the controversial issues associated with their health effects.

Jan 1, 1988

By T. Sakaguehi

Some attempts were made to recover and remove of uranium that may be present in refining effluents, mine waste Water, and other waste sources by using microbial biomass. To establish which microorganisms accumulate the most uranium, 135 species of microorganisms (42 bacteria, 26 yeasts, 34 fungi and 33 actinomycetes) were screened. Of these 135 species of microorganisms tested, extremely high uranium absorbing ability was found in Pseudomonas stuzeri, Neurospora sitophila, Streptomyces albus and Streptomvces viridochromogenes. In addition to the research on uranium uptake, thorium recovery by using microorganisms was investigated. High abilities were found in Streptomyces levoris and Bacillus subtilis. The selective accumulation of heavy metal ions by various microorganisms has also been examined. Uranyl, mercury and lead ions were readily accumulated by almost all of the species of microorganisms tested. Actinomycetes and fungi differ from many bacteria and most yeasts in their selective accumulation of uranium, and mercury. The basic features of uranium uptake by Streptomyces viridochromogenes, a microorganisms with high uranium-uptake ability, were investigated systematically. Synthesizing these results, we suggested that the accumulation of uranium into these microbial cells is not directly mediated by any metabolic process:, but almost completely dependent upon physicochemical adsorption on the cell components. In addition to this fundamental research, uranium recovery was investigated in immobilized Streptomyces viridochromogenes. These immobilized cells adsorbed, uranium readily and selectively. The immobilized cells recovered uranium almost quantitatively and almost all uranium adsorbed was desorbed with 0.1 N Na2CO3, These results showed that microbial cells are more stable after Immobilization and can be used repeatedly for the process of uranium adsorption-desorption. These results suggested that these microbial cells can be used for the recovery and removal of nuclear fuel elements, such as uranium and thorium, from refining effluents and mine waste water.

Jan 1, 1991

By G. K. Ruhlandt, C. W. Kim

"A 3-D Finite Element Method program called ""SOLCAST"" has been developed to simulate the casting solidification process. Using the temperature recovery method to evaluate the latent heat of fusion and applying a new combination of the time integration scheme, SOLCAST reduces the computational time significantly compared to an existing commercial FEM program, and produces accurate results comparable to experimental casting results. Prediction of casting shrinkage porosity for A390 aluminum alloy will also be discussed. To make this FEM program useful for foundry engineers, this program was connected to a commercial pre- and post-processor.IntroductionBecause of recently increased competition, foundrymen must produce high quality castings more economically. Therefore, casting solidification analysis prior to casting production is an attractive way to reduce costs and development time.Although the actual casting solidification process is a very complicated phenomena, foundrymen could predict where shrinkage defects would occur based on a transient conduction heat transfer analysis that includes the liberation of latent heat. A numerical analysis is generally required to solve the heat diffusion equation with the latent heat diffusion term, because casting shapes are very complicated and pure materials are rarely used.Different numerical methods have been applied to the casting solidification analysis 1. Among them, a finite difference method 2 and a finite element method (FEM)3 are most commonly used.Each simulation method has one or more basic difficulties which are different for each method. These difficulties are:(1) Modeling casting shapes on a computer.(2) Time consuming computation.(3) Uncertain material properties."

Jan 1, 1986

By Kang-In Rhee

A series of processes to recover the gold from electronic scrap which contains initially about 200-600 ppm Au have been developed. First, mechanical beneficiation including shredding, crushing and screening was employed. Results showed that 99 percent of gold component leaves in the fraction of under 1 mm of crushed scrap and its concentration was enriched to about 800 ppm without incineration. The scrap was leached in 50% aqua regia solution and gold was dissolved completely at 60°C within 2 hours. Other valuable metals such as silver, copper, nickel and iron were also dissolved. This resulting solution was boiled to remove nitrous compounds in the leachate. Finally, a newly designed electrolyzer was tested to recover the gold metal. More than 99% of gold and silver were recovered within an hour in electrowinning process.

Jan 1, 1995

By Y. Maeda

Non-ferrous smelting furnaces generally lnstal1 a gas cooling system for treatment of waste gas containing S02. From the point of view of corrosion resistance and recovery of waste heat, the high pressure boiler system Is the best way to cool gas, however this system requires high Initial investment and relatively higher operating costs. Because the feasibility of this boiler system greatly depends on the smelting process and scale, other lower temperature systems, e.g. water-cooled Jacket system, are more suitable If the smelting process does not produce enough steam nor generate enough electricity to compensate operating cost. In addition, the water-cooled Jacket system Is simple in structure and easy to operate. For those reasons, it is applied widely. A new smelting furnace. was planned tin our factory and It was necessary to install waste gas cooling equipment. In our case, a water-cooled Jacket system was mo11e feasible because of the low gas volume and high dust content. H was also expected to operate without maintenance for ten years. On the other hand, some leakage problems with the water-cool1ed Jacket had been experienced In the past. That is because S02 in the waste gas changed into sulfuric acid which corroded the Jacket material, As the first step, several data from actual usage were reviewed to throw light on the corrosion process, and an appropriate procedure to determine the operating temperature of cooling water was obtained. For the basis of this study, a water-cooled Jacket system was newly designed and tested for three months in a pilot plant. After this system's performance was confirmed, It was installed In a new furnace as a commercial pl.ant. After one year of operation, the initial thickness of carbon steel Jacket remains almost the same.

Jan 1, 1992

By Nicholas Zabaras, Deep Samanta

"Solidification of metal aluminum and aluminum alloys is modeled on uneven surfaces characterized by sinusoidal curves. Wavelengths and amplitudes of these sinusoidal surfaces are varied to study their effects on processes like solidification, macro-segregation and inverse segregation. Solidification and macro-segregation are modeled using a slightly modified form of a stabilized finite element method developed recently to model high Rayleigh number solidification and porous media flows. For pure metal solidification, the effect of varying amplitudes and wavelengths is observed in heat transfer, fluid-flow ~nd phase change processes. The relative importance of shrinkage driven flow and solutal convection on the redistribution of solute for an alloy solidifying in a rectangular cavity is compared. The analysis is then extended by modifying one of the surfaces to a sinusoid. In this case the effects of varying amplitudes and wavelengths are studied in heat transfer, fluid flow, phase change, macro-segregation and inverse segregation processes.1 IntroductionTransport phenomenon during solidification of alloys is a major cause ofcasting defects such as segregation, micro-voids, hot tears, porosity, internal and surface cracks. Heat flow across metal and mold surfaces directly affects the phase change process and plays an important role in determining freezing conditions within the metal. In alloys, natural convection and shrinkage play an important role in determining the final solute redistribution, macrosegregation and evolution of solid macromorphology. Surface unevenness plays an important role during the early stages of solidification. It influences the heat transfer rate and fluid flow in the melt, which in turn affect the morphology and shape of the solid-liquid interface. The effect of surface unevenness on solute redistribution is important during solidification of alloys, where solute driven flow in the mushy zone is prominent. Thevik and Mo in [7] and [8] used a one dimensional model for studying surface segregation and macrosegregation in alloys under the influence of exudation and solidification shrinkage. Air-gap formation in their model was expressed through a variable convective heat transfer coefficient at the boundary. Tsai et al. in [3] and [4] have modeled macrosegregation in an aluminum-copper alloy driven by shrinkage and solutal convection. They used a single domain model based on mixture theory and solved the transport equations using finite difference methods. Our aim is to model solidification of aluminum followed by macrosegregation and inverse segregation in aluminum-copper alloys on uneven surfaces by finite element methods. These surfaces are modeled as sinusoids characterized by amplitudes, ?s and wavelengths, As, By varying As and ?s, changes in heat transfer, fluid flow, phase-change and macrosegregation are studied."

Jan 1, 2004

By J. K. Brimacombe

Since the Peirce-Smith converter was introduced to the non-ferrous industry in the early part of this century, there has been a paucity of research on process-engineering aspects of the reactor such as gas injection. This paper reviews studies conducted at UBC over the last decade on gas discharge dynamics, high-pressure injection, bath slopping, oxygen/bath reaction kinetics and out-of-stack heat transfer within the converter. The ultimate objectives of this work have been to extend refractory life and to increase converter productivity.

Jan 1, 1985

By Zemin Ma

A novel chromate [Cr(VI)] reducing bacterium was isolated from chromite ore processing residue disposal site of China and identified as a Leucobacter sp. by 16S rRNA gene sequence homology. The minimum inhibitory concentration of strain CRB1 was 820 mg l-1 of Cr(VI). The reduction of Cr(VI) occurred only under aerobic conditions. With an initial concentration of 2.5×108 cells ml-1, 1800 mg l-1 of Cr(VI) was reduced entirely within 38 h under the optimum conditions, at 30 °C and pH 9.0. Increasing Cr(VI) concentrations prolonged reduction process and higher cell densities meant quicker reduction. A blue precipitate was produced during chromate reduction of strain CRB1, which was binding to the surface of bacterial cells and determined as trivalent chromium with electron paramagnetic resonance (EPR) spectrometry. The conspicuous chromate reduction ability of Leucobacter sp. CRB1 suggested a potential for bioremediation of Cr(VI) containing wastes.

Jan 1, 2008

By Lijun Lu, Honghui Fang

This article carried out the experimental study on using desulfurization ash in steel slag composite material. This was done by investigating the desulfurization ash content in formula one and formula two samples on the influence of setting time and strength of mortar. Through this study the following conclusions were reached for formula one: (1) a setting time of more than 10 hours is required, (2) a dosage of desulfurization ash of 1 ~ 2% is optimal, where flexural strength is reduced by 10% ~ 23% and compressive strength reduced by 5.7% ~ 16.4%. The conclusions of formula two were: (1) when the dosage of desulfurization ash is within 5%, the setting time is within 10 hours; (2) when the dosage of desulfurization ash is 1 ~ 2%, the flexural strength is increased by 5 ~ 7% and the compressive strength is reduced by 1 ~ 2%. The results show that the formula two is better.

Jan 1, 2015

By C. T. Philipp

Recycling of waste is much preferred over disposal. This paper discusses the Enviroscience, Inc. (ESI) process, now being commercialized by MetWool, Inc., to recycle hazardous wastes using an extractive metallurgical process which is followed by vitrification of non-reducible metal oxides. In this process, volatile and reducible metals are reclaimed as their respective oxides and elements.

Jan 1, 1995

By Y. F. Liang

Fe-6.5wt.%Si alloy has excellent soft magnetic properties compared with conventional silicon steel. It is very brittle at room temperature due to appearance of ordered phases, like B2 and DO3. In this paper, we investigate the effect of ordering on cold workability of this alloy. Methods of rapid quenching and hot rolling were utilized. It is found that rapid quenching and proper heat treatment of the hot rolled sheet could decrease the degree of order due to the very high solidification rate and high cooling rate. The rapid quenched sheet and hot rolled sheet after proper heat treatment could be cold rolled without crack. Microstructure, phase ordering, micro hardness, and cold rolling properties were investigated by Optical Microscope, X-ray Diffraction, Micro Hardness Indenter and Four-high Mill.

Jan 1, 2009

By R. Ratnagiri, B. Minaie

"In order to expeditiously produce defect-free metallic components in materials processing applications, the relationship between the process parameters and the product properties needs to be well understood while minimizing the production engineering iterations. To achieve this goal, a realistic mathematical formulation of the process should be carried out and an appropriate numerical modeling of various phenomena occurring in such process should be implemented. The materials processing of transforming the molten material into a finished metallic component involves fluid flow and solidification/melting. In the present paper, a finite element based analysis of the fluid flow ·and solidification/melting phenomena in cavities is presented and the various issues in modeling these phenomena are discussed. These transport phenomena play an important role in determining the final characteristics and material properties of the part by affecting the formation of defects and microstructure. A realistic numerical modeling of these phenomena can significantly reduce the rejection rates during the process and can increase the quality of the final product.IntroductionDuring the intelligent materials processing of various metallic components, it is often required to have a thorough knowledge of the behavior of the transport phenomena involved in this process. This is due in large to the coupling that exists between the transport phenomena and the final material properties of the components produced during materials processing. This interrelationship demands that the pertinent transport phenomena in the form of fluid flow and solidification/melting be studied and predicted accurately. In many materials processing applications, the fluid flow is in the form of either a forced convection free surface flow intended to fill a cavity or a natural convection flow resulting from the gravity when the cavity is filled. In either case, the phase change in the form of solidification/melting is also involved in order to complete the process. However, the thermal history during this phase change has a direct impact on the material properties of the final part and the possible defect formation that may be involved. This thermal history itself is dependent on the nature of the fluid flow during the earlier stages of the process. As such, there is a coupling between the fluid flow, phase change, microstructure, and defect formation in the resulting component. It is therefore necessary to analyze these phenomena in order to find optimum methods to produce good quality parts by minimizing the defects that may be generated. Such an analysis can result in the development of appropriate numerical models for the process that can facilitate the economical and timely manufacturing of various components with high consistency. The present paper discusses the issues related to the transport phenomena encountered during materials processing of components engineered largely by using various combination of convective fluid flow and solidification/melting in cavities."

Jan 1, 1994

By Stanko Nikolic

The Top Submerged Lance (TSL) technology, developed in the 1970s, is now widely used for the processing of a range of materials. TSL technology for continuous converting was first patented in the 1990s. The process is based on the use of calcium ferrite slag. Although this slag system had been applied elsewhere the phase equilibria had not been thoroughly investigated. This lead to a collaboration between the Process Technology group of Mount Isa Mines, now part of Glencore, and the Pyrometallurgy Innovation Centre (PYROSEARCH) at The University of Queensland. Through multiple research programs this complex system was successfully investigated. The results were then implemented within thermodynamic modelling tools. This combined new knowledge was then applied to the design and industrial implementation of the TSL continuous converting technology, ISACONVERT™. This paper describes the key findings of the research and how this was applied to the industrial implementation of the technology.