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Segregation roasting tests were carried out on Zaire cobalt oxide ores assaying about 2% Co and 3.5 to 6.5% Cu. The major parameters tested during the laboratory investigations were temperature, dosage and type of reducing agent, dosage and type of chloridizing agent, and particle size. Results showed that standard conditions suited to the segregation of copper ores, i.e. low temperature and low dosages of reducing and chloridizing agents, resulted in the segregation of copper only, while conditions suited to the segregation of lateritic nickel, i.e. higher temperature and increased dosages of reducing and chloridizing agents, led to a successful segregation of both copper and cobalt. Under the best conditions, 88% of the cobalt and 98% of the copper could be recovered in a concentrate assaying 32.5% Cu and 8.5% Co. Alternatives to process such a concentrate are briefly reviewed.

Jan 1, 1993

By S. A. Shuey

The present industrial practice used to separate aqueous cobalt from nickel is multistage solvent extraction processing. This paper describes a different but simpler treatment technology. The proposed technology has been applied to cobalt/nickel hydroxide intermediate solids produced from the treatment of Electrochemical Machining (ECM) waste sludge, The process consists of dissolving the cobalt/nickel hydroxides in basic cyanide solutions. Cobalt and nickel form aqueous .solution metal cyanide complexes. Nickel can be selectively precipitated from the solution as a nickellic hydroxide solid. Cobalt can be recovered from the leach solution by precipitation of a cobaltous/cobaltic cyanide double salt. The double salt product can then be subsequently treated to produce an appropriate cobalt product. The process chemistry, proposed fiowsheet and preliminary reagent costs are presented and discussed.

Jan 1, 1998

By Jiang Feng, Li Chuanhua, Zhang Libo, Peng Jinhui, Ju Shaohua

Solvent extraction of Cu2+ from the leaching liquor contain Cu and Fe use a microfluidic technology. Currently, the conventional copper extraction process has many problems such as long distance and small driving force of mass transfer. In order to solve the problems, studies are carried out on the extraction process of low grade copper leaching liquid using Lix984N as an extractant with a new microfluidic solvent extraction technology. The effects of flow rate on the separation and extraction efficiency between Cu and Fe are studied, and the results show that a steady liquid-liquid interface of laminar flow is form in the micro-extractor, and extraction efficiency is 78 % and 2.5 % for Cu and Fe at the contact times of 0.84s respectively. Besides, the separation coefficient between Cu and Fe is as high as 140.04. The studied microfluidic technology has the advantages like improving extraction efficiency and reducing reaction time and providing the potential application in the hydrometallurgy extraction of Cu.

Jan 1, 2015

By F. Tailoka

Microporous membranes have been used to create a very fine dispersion of bubbles which greatly enhances the mass transfer of electroactive species to the electrode. Using this system, it has been shown that it is possible to electrowin copper as a coherent planar deposit, at high current densities, from copper chloride solutions.

Jan 1, 1990

By Gus Van Weert

Solvent extraction of iron from zinc refinery liquors has been investigated before, mainly on the MEHPA / HC1 stripping combination. Leakage of chloride into the zinc electrolyte and the costs of handling the ferric chloride eluate have prevented this option from being adopted. This work explores the stripping of the ferric loaded organic phase with nitric acid to take advantage of the possibility of regenerating up to 6N nitric acid, and clean spheroidal hematite production by autoclave treatment of ferric nitrate solution. The work was carried out with DEHPA (di 2-ethyl-hexyl phosphoric acid) in kerosine. Degradation testing proved the DEHPA to be very stable, when exposed to nitric acid solutions up to 6N and temperatures up to 70" C over a period of five days. Ferric iron was removed completely froma synthetic hot acid leach liquor, irrespective of the DEHPA concentration. Stripping the ferric turned out to be the problematic step. Although the stripping efficiency was considerable better at 50 than at 20° C, it decreased with increasing DEHPA/Fe ration in the organic phase. Eluates of no more than 5-10 g/l ferric nitrate were produced. surprisingly, nitric acid was found to be a less efficient stripping agent than sulphuric at equivalent normality and its efficacy levelled off above 4N. It was concluded that DEHPA does not appear to be the S.X. reagent to take advantage of the low cost autoclave decomposition of ferric nitrate opportunity in zinc hydrometallurgy and that another S.X. reagent, also resistant to nitric acid, but based on weaker compound formation is needed.

Jan 1, 1998

By Zhang Chuanfu, Tan Pengfu

"A thermodynamic model is developed to simulate nickel flash smelting process. In the nickel flash furnace, oxidation of concentrate occurs at one end, and reduction of slag occurs at the other. The model makes use two zones, namely the reaction shaft/settler zone and the appendage zone and accounts for 6 phases (matte, slag, silica, magnetite, Cu-Ni alloy and gaseous phase), 13 elements (Ni, Co, Cu, Fe, S, 0, N, C, H, Si, Al, Mg and Ca) and 33 chemical components in nickel flash smelting system. The compositions of matte, slag and gaseous phases in equilibrium are calculated by using the data of free energies of formation and activity coefficients of components. Two nickel sulfide species are used to allow for the modeling of sulfur-deficient mattes. The model predictions are compared with the known industrail data from Kalgoorlie Nickel Smelter, and excellent agreement is obtained. The model can be a very useful tool for monitoring and optimizing the actual industrial operations of nickel smelting process. The distribution behaviors of Ni, Co, Cu, Fe, S and 0 in the nickel smelting furnace depend on the process parameters such as smelting temperature, volumes of air, the content of the elements~ charge and oil.1. IntroductionThe nickel flash smelting furnace essentially consists of a reaction shaft where nickel sulfide concentrate is partially oxidized with air, a settle zone where matte and slag are allowed to separate, and a slag cleaning end where coke is added to provide for the reduction of the oxidized nickel from slag, and electrodes are used to provide heat.The theoretical model to consider a mass balance for copper flash furnace is developed by S. Goto and R. Shimpo[1][2J. However, this can not be true for nickel flash furnace as a whole since oxidation of concentrate occurs at one end (in the reaction shaft/settler), and reduction of slag occurs at the other (in the appendage). Despite these limitations, an acceptable pseudo-thermodynamic description of the furnace can be achieved using essentially two zones, namely the reaction shaft/settler zone and the appendage zone. Compositions of gas, slag and matte in two zones are calculated."

Jan 1, 1998

By Jared Ball, Darren Snashall, Paul Telford, Pengfu Tan, Ben Hogg

"The foamed converter charges were up to 3 8 per month in Xstrata Copper Smelter at Mount Isa. The issue of high converter foamover frequency had remained unsolved for many decades in Mount Isa. A thermodynamic model of copper P-S converter and a viscosity model of converter slag have been developed to simulate the slag blow and copper blow, in order to understand the mechanism of converter foamover. The model predicts the chemistry and viscosity of slag during slag blow and copper blow. The effects of oxygen potential, charge of dirty reverts, slag carryover, under-blowing, over-blowing, and temperature on the foamover and viscosity of slag in copper blow have been discussed. A theory has been developed to understand the mechanism of converter foamover. The practical solutions have also been developed and implemented in Mount Isa Copper Smelter. Some improvements of the industrial operations have been presented. After a series of improvements, the number of foamed charges per month in the converter operations has been decreased significantly from 35 in Aug 2008 to only one per month in 2009/2010.1. IntroductionThe Copper Smelter in Mount Isa receives the concentrate containing about 25% copper and produces anode copper that contains about 99% copper. There are several stages in the process. The first stage carries out in the ISASMELT™ furnace. The ISASMELT™ process produces a molten copper matte containing about 60% copper. An iron-silica slag and a sulfur dioxidebearing off-gas are the by-products of the process. The slag is taken to the slag dams for cooling before it is recycled through the Mount Isa Copper Concentrator.The matte is sent to Peirce-Smith converters. The converters further remove iron and sulphur to produce blister copper which contains about 97% copper. The anode furnaces remove any remaining sulphur and oxygen to produce anode copper that is about 99. 7% pure. This is cast into anodes and sent to the Xstrata Copper Refinery in Townsville for final refining.In the copper pyrometallurgical industrials, slag foaming is an important phenomena which occurs when the gas bubbles have stability and not rupture. Foaming greatly increases the interfacial area between matte, slag and gas and is essential for the operation of high intensity smelting processes. However, foaming or foamover is undesirable in P-S converter since it can damage the equipment and injure the operators. Figure 1 shows that the whole process of a foamover development in a converter."

Jan 1, 2011

By Augusto Viana Leandro Teixeira

Rare Earth Elements (REE) are fundamental for modern life products and green technologies. Supply constraints and the price peak of 2011 boosted intensive research for alternatives for processing and separation. Complex monazite- type, rare earth ores usually contain high acid consumption impurities, such as iron and aluminum, and radioactive thorium in their composition. These impurities are not removed by conventional concentration processes due to fine, micro-level association between the REE carrying minerals and the gangue minerals. This work presents a selective process route for REE extraction from iron-rich, monazite ores. The process involves sulfation by addition of concentrated sulfuric acid and pyrohydrolysis at temperatures of approximately 700–750 °C. Experimental results show REE extraction higher than 70% and low iron (below 5%) and thorium extraction (below 10%). A method based on thermogravimetric analyses was shown to be adequate to predict the behavior of a given ore sample in the sulfationselective pyrolysis-leaching process.

By Valdeci Paula Alvarenga, Sergio Luiz Costa, Itavahn Alves da Silva, Filipe Bueno Carvalho, Varadarajan Seshadri, Carlos Antonio da Silva

Use of fluorspar in steel refining operations is one of the environmental concerns and as such reduced consumption of this material or substitution of the same is one of the objectives. Industrial runs were carried out at Aperam Steel making convertor unit (Timóteo, MG, Brazil) using recycled/briquetted slag for partial or complete substitution of fluorspar. Samples were collected from the metal bath and slag after oxygen blowing to assess dephosphorization with several combinations of recycled/briquetted slag and fluorspar. The results showed that partial substitution of fluorspar by BOF slag briquettes did not affect the efficiency of dephosphorization. In general average Phosphorus content was reduced to 0.010% in the case of partial substitution compared to 0.016% in the regular refining procedure with no substitution. This replacement also resulted in 40% reduction of the fluorspar consumption in the converter

Jan 1, 2015

By Liu bing-guo, Peng Jin-hui, Guo Sheng-hui, Kong dong-cheng, Hu jin-ming, Zhang Li-bo

The novel technology of calcination to prepare triuranium octaoxide（U3O8）from ammonium uranyl carbonate in microwave fields was investigated on the basis of the temperature rising characteristics of ammonium uranyl carbonate, triuranium octaoxide (U3O8), and their mixture. The result of experiments show that ammonium uranyl carbonate had weak capability to absorb microwave energy, while triuranium octaoxide has the very strong capability to absorb microwave energy and the sample temperature increased rapidly with an increase mixture ratio of triuranium octaoxide. The optimal calcination conditions were as follows: microwave power 700 W, calcination time 10 min and 60 g in this experiments range, respectively. Under these conditions the value of total uranium and 4 U of triuranium octaoxide was 84.28% and 31.02%, respectively. It is feasible to prepare triuranium octaoxide by calcination from ammonium uranyl carbonate, which mixed with small amounts of triuranium octaoxide under microwave fields.

Jan 1, 2015

By H. Y. Sohn, M. K. McCarter, Bradley C. Paul

"A computer model was constructed for bacterial leaching of the major sulfides found in porphyry deposits, including bornite, chalcocite, chalcopyrite, covellite, cubanite, enargite, native copper, pyrite, and pyrrhotite. The model incorporates equations for the sulfide minerals dispersed in the rock matrix. Leaching occurs by reactions with ferric ion diffusing into the rock fragment: Ferrous ion is resenerated to ferric with oxygen by bacteria at a temperature dependent rate. The model keeps track of the net acid generated, oxygen consumed by the bacterial oxidation of ferrous ion, heat generated, jarosite and hematite precipitated, and copper leached. The model was used to predict the rate of copper recovery, heat generation and oxygen demand for a variety of run-of-mine sized porphyry ores. These results were used in the design of a ventilation system and the economic analysis of a modified in situ extraction method that may be cost competitive with conventional copper production involving open pit mining.IntroductionA study was undertaken at the University of Utah to evaluate the technological and economic feasibility of mining copper by a method referred to as Flood Drain Leach Cell (FDLC) mining. Cells 60 by 75 meters in plan and 70 meters in height are created throughout the ore body by a modified Vertical Retreat Mining technique that includes the removal of 25% swell material. The swell material is leached in finger dumps on the surface while the cells underground are bulkheaded, flooded, drained, and artificially aerated to promote bacterial ferric sulfate leaching. Solutions are cycled through several cells to reach pregnant grade of 1 gram copper per liter of solution. These solutions are then fed to an underground solvent extraction plant and then a surface electrowinning tankhouse."

Jan 1, 1988

By Denis Shishin

The pyrometallurgical production and recycling of non-ferrous metals involves the use of complex feed stocks, having awide range of chemical compositions from sources that include mineral sulphide concentrates, high value obsolete materials and process wastes. The commercial viabilities of these operations hinge on the ability to extract value from these materials. Increasingly, modern computer-based tools are used to describe and predict process outcomes, including mass and heat balances, the partitioning of elements and phase equilibria. At the heart of these predictive tools are thermodynamic databases that describe the fundamental chemical properties of a system and all the components present. A comprehensive research program has been established to develop an accurate, self-consistent thermodynamic database describing all gas-slag-matte-metal-speiss-solid phases in the system Cu2O-PbO-ZnO-Al2O3- CaO-MgO-FeO-Fe2O3-SiO2-S-(As-Bi-Sb-Sn-Ag-Au). The database can be used in conjunction with the FactSage computer platform. The accuracy of the database and its application to industrial practice is demonstrated.

By Janusz Majta

The aim of this work is to investigate the control of microstructure evolution through variation of particular deformation parameters in the two-phase (intercritical) region. Niobium-microalloyed and low-carbon steels were investigated. A detailed examination of the factors affecting the ferrite microstructures of tested steels indicated that there were distinct advantages of finishing at temperatures in the austenite-ferrite region. The various results of deformation in the two-phase region are presented. Consequently, the influence of the most important process parameters on the microstructure evolution and mechanical response of the material is determined. The prime objective of the realized research work is the determination of relationship between the history of deformation and final product quality i.e. texture and mechanical properties. To reach the objective, the constitutive equations are proposed for modeling the effects of the hot-deformation process occurring in the austenite and austenite-ferrite region of low carbon and microalloyed steels on the mechanical properties of the resulting product. These models link advanced, finite element approaches simulating metal flow and heat transfer during hot-plastic deformation with constitutive equations describing microstructural processes and mechanical properties.

Jan 1, 2003

By O. Durand

The Cerro Verde Hydrometallurgical Plant, located at Arequipa in the southern part of Peru, started its operation in 1977 with a design capacity of 33,000 MT/year of copper cathodes. The plant has treated 61,055,000 MT of ore mainly oxides with a content of 1.01% total copper and 0.67% of soluble copper. The leaching plant has three pads that produce 4.0 gpl copper solution. The solvent extraction plant has four trains with three extraction stages, two stripping stages with a single mixer in all stages. The mixer-settlers are 316 stainless steel and the pumps are vertical turbines. The flowrates of 1,300 gal/mil of aqueous and 1,300 gal/min of organic at a 1/1 ratio. The electrowinning plant contains 208 commercial cells and 18 starting sheet cells. Each cell has 47 anodes and 46 cathodes. In addition to describing the hydrometallurgical plant, this paper also mentions efforts directed at reducing costs and improving operations. The initial results from leaching secondary sulfides, which started October 1985, are also discussed.

Jan 1, 1987

By C. P. Broadbent

The process metallurgy of many nickel laterite smelting operations is controlled largely by the physical chemistry of the slag system. Consequently, accurate phase diagram information and physicochemical property data are essential to interpret and predict the behaviour and optimisation of the overall process. The system (SiO2 - MgO - FeO) first described by Bowen et al. between 1914 and 1935 and the system (SiO2 - MgO - FeO - Fe2O3) determined by Muan and Osborne in 1956 are of particular relevance to the study of nickel laterite smelting slags as these systems form a reasonable approximation of many industrial slags. This paper will review the literature for these (and other relevant) phase systems. In addition data available from the ternary and (quasi)ternary phase diagrams will be compared with data obtained from industrial slags. The physico-chemical properties under consideration will include; melting and crystallisation behaviour (solidus and liquidus temperatures), viscosity - temperature relationships, heat flux considerations, electrical conductivity, surface and interfacial tension.

Jan 1, 1993

By C. Isaac Garcia, Sihai Jiao, Anthony J. DeArdo

"A practical model based on the Hill analysis has been developed to calculate the Lankford value of interstitial free (IF) steels and its distribution in different rolling directions, by considering only a few selected texture components. The Texture Intensity Ratio (TIR), i.e. (111 ) /(100), was used in the model to describe texture. By using the new TIR parameter, the texture-based prediction models can be used more easily to predict the Lankford value in a rather straightforward way.IntroductionThe deep drawing capacity of sheet steels is generally indicated by the Lankford value, which is mainly determined by the texture in steels1. Traditionally, various models derived from the Taylor model are employed to calculate the Lankford value from the texture2-4. In such models, the plastic deformation of steel is assumed to be the result of the slip of dislocations in certain slip systems, i.e., by either pencil glide or restraint glide. The slip direction is the <111> direction. In the case of pencil glide, the slip is thought to be possible in all crystal planes with the <111> crystal direction. Assuming the material is elongated in the X1-direction by d n and compressed in the X2 and x3-direction by qd n and (l-q)d n, respectively, corresponding to a deformation tensor"

Jan 1, 2001

By L. I. Rosato

A novel hydrometallurgical process for the recovery of silver and gold from neutral leach residue that is based upon leaching with thiourea, is described. Laboratory and pilot plant studies have shown that 80-90% of the silver and 60-70% of the gold can be recovered by:? ( i) leaching zinc calcine with &apos;Spent electrolyte at pH 2.0-3.0 to generate a precious metal-bearing zinc ferrite residue, (ii) leaching of the thickened zinc ferrite with 3-5 g/L thiourea in a six stage carbon-in-pulp circuit, (iii) elution of silver and gold from the loaded carbon with a thiourea- butanol solution, (iv) thermal regeneration of the stripped carbon and (v) recovery of the precious metals from the pregnant eluate by cementation with zinc dust. The reasons for adopting the thiourea CIP leach and the preferred operating parameters for each process step are presented. The requirements for the destruction of any thiourea transferred to the zinc circuit are outlined, and the results of an integrated one tonne/day pilot plant operation at Canadian Electrolytic Zinc are given.

Jan 1, 1990

By P. Kerr

Iron segregation is pre-dated by copper and nickel segregation processes for which the experimental methodology and reaction chemistry were established. The accepted reaction sequence for segregation involves the generation of hydrogen chloride, the chloridization and volatilization of the metal chloride, and precipitation of the metal from the metal chloride in the vicinity of carbon. Iron segregation roasting offers a potential extraction solution for processing oxide deposits with complex mineralogy or waste streams such as Minette-type iron deposits, nickel laterites, ilmenite, red mud, electric arc furnace (EAF) dust, mill scale and slag. After subsequent magnetic separation, one is left with a high grade metallic iron powder which can be marketed for powder metallurgy or briquetted to serve as a direct reduced iron (DRI) product. The non-magnetic product is typically concentrated oxides including rutile, alumina, or oxides of V, P, and rare earths, etc. that may be economically recoverable with subsequent processing. While operating conditions vary for different metals, they share the requirements of an elevated operating temperature and a mixture of oxide ore, carbonaceous additive and a chloride additive in varying amounts all in a closed reactor to allow for reducing conditions and contain the volatile chlorides. This process is then followed by some form of physical separation. Testwork performed by the authors shows promising results that may aid in future development of the process. Segregation roasting of iron will likely never displace traditional beneficiation and ironmaking technologies; however, it has great potential in niche markets where traditional technologies have failed or current technologies generate substantial waste.

By J. Phillip Mackey

The Peter Hayes Symposium on Pyrometallurgy, held as part of Extraction 2018, is an acknowledgement of his contributions to the basic science and principles underpinning modern pyrometallurgical processing. After completing his PhD at Strathclyde University, Scotland, in 1974, Peter took up a teaching position at The University of Queensland, Brisbane, Queensland, Australia in 1976. Peter Hayes’ research at the University since then has been focussed on: • The mechanisms and kinetics of heterogeneous solid/solid, gas/solid and liquid/ solid reactions, and • Experimental measurement of phase equilibria in complex high temperature metallurgical systems. This paper provides a brief biography of Dr. Peter Hayes and gives a full listing of Peter Hayes’ publications.

By Rolf R. von Oppenfeld

Onsite hazardous waste processors often find obtaining a Treatment Storage and Disposal (TSD) permit one of their first major challenges. Some processors may spend the time and money required by the permitting process, only to find out later that a permit was not necessary. This paper will present and analyze four strategies that processors may use to avoid obtaining a TSD permit. Some facilities will be able to remove their waste streams from RCRA&apos;s oversight by ensuring the material is not "hazardous" waste. Parties that treat waste while it is in process may be able to avoid generating "waste" altogether. Certain treatment facilities have been specifically exempted by EPA. Finally, treatment of waste while it is in generator storage tanks may be allowed without a RCRA TSD permit. Hazardous waste point of generation, an important determination relating to these strategies, will also be discussed. Generators and processors will find this paper useful when evaluating their permit exemption potential

Jan 1, 1996