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Equilibrium calculational software programs can be effectively utilized to illustrate the importance of activity or concentration, solubility, temperature, solution pH, solution potential, and ligand complexation to students studying hydrometallurgy. The calculational program STABCAL will be demonstrated. illustrative examples for the creation of diagrams such as EH-pH, activity or concentration-pH and activity or concentration-EH will be presented to demonstrate the fundamentals of real hydrometallurgical systems. Speciation, titration and mixing will be used to simulate or predict operational processes. Applications will include treatment of Acid Mine Drainage (Berkeley Pitlake water and sediments), mass balance potential/pH diagrams, leaching and selective separation of metals from electroplating sludge, metal adsorption at femhydrite surfaces, and flowsheet development for treating mercury sulfide K106 sludge.

Jan 1, 2002

By Arsenio Enriquez, Adrian Deneys

"Rio Tinto through its subsidiary Kennecott Utah Copper Corporation (KUC) and Praxair have implemented the CoJet® gas injection system for copper anode refining. The system provides the capability to melt on average 60 to 70 tons of scrap copper per heat (with acceptable NOx emissions). The system has demonstrated the potential for tuyere-less sulfur and oxygen removal using coherent jet technology.This paper describes the process concept, system development, laboratory testing, implementation, current operation and ongoing developments."

Jan 1, 2009

By Mokka Rao, Asdrubal Serrano

"A mathematical model is developed which describes the movement of the minerals present where the vertical and angular velocities are related with the different operative parameters involved in the process of separation of silica from iron ore, which permit maximise the capacity of the spirals to obtain major productivity. The process is realised in two steps, of the rough dressing and other cleaning. Through the results obtained for chemical analysis of the final products of each spiral and the equation of movement of particles, it is proved the applicatibility and efficiency of mathematical model to operating parameters of the spiral. Moreover, it is determined though the recuperation of the final products of quality in the use spiral HC 1870 and HG 8/7. INTRODUCTIONThere is prospetive of increasing the production the iron ore in agreement with the demand of siderurgical proyects united with the external demand of quality 40 million tons per year. The Ferrominera de Orinoco Company is experimenting two types of modem spirals, Humprey (HC 1870) and Reichart (HG 8/7) which have limited capacity. For this reason this investigation designed a mathematical model with which larger units can be designed for increasing the capacity of the spiral."

Jan 1, 1999

By Jillian Spindura

This work investigates the carbothermic reduction of the complex sulphide mineral, pentlandite, in the presence of lime. The effects of change in temperature and the use of different carbon sources are studied and the role of these variables on the reducibility of pentlandite mineral is discussed. The microstructures of the heat-treated pellets are examined using X-ray diffraction and scanning electron microscopic techniques. The latter analytical method also allows any variation in the morphology and composition of the metallic phases formed, with temperature, to be considered. The kinetics of the reduction process is studied and the magnitude of the overall activation energy is determined from the plots of percentage reduction versus time.

Jan 1, 1996

By William K. Connor, O&apos

The U.S. Bureau of Mines (USBM), in cooperation with the American Society of Mechanical Engineers (ASME), conducted over 200 hours of melting tests to vitrify residues from five municipal waste combustion facilities. Combined residues (grate residue and f1yash) from three municipal waste combustors, a waste water treatment sludge combustor, and flyash from a refuse-derived-fuel (RDF) boiler, were sequentially melted in a I-metric-ton (mt) water-cooled-wall electric arc furnace. Each of the residues underwent magnetic separation, screen size analysis, and bulk chemical analysis prior to melting. The furnace products were examined by optical and electron microscopy and by X-ray diffraction. Bulk chemical analyses were acquired for the metal, fume, and vitrified furnace products. The material balance for the furnace operation indicates that from 69 to 86 pct of the feed reported to the vitrified furnace product, which had leaching potentials well below the EPA limit for each metal, as determined by the EPA TCLP. The electric arc melting furnace currently is being utilized in a cooperative research project between the USBM and the Idaho National Engineering 'Laboratory (INEL) for melting tests on simulated low-level radioactive wastes,

Jan 1, 1991

The high pressure acid leach process (HPAL) is being commercially used in four plants around the world to treat limonitic laterites. The two major operating costs of the HPAL process are the sulphuric acid and the energy required to heat the pulp to the desired temperature (>240°C). As an alternative to acid injection and steam heating, the in-situ generation of sulphuric acid and heat, produced during the high temperature pressure oxidation of sulphur-bearing materials blended with laterites, has been investigated at the laboratory scale. Various sources of sulphur have been examined, in particular, elemental sulphur, pyrrhotite and a Cu-Ni low-grade bulk concentrate. Under the proper blend ratios, all sulphur sources tested generated sufficient acid to result in equivalent nickel and cobalt dissolutions. A significant improvement to the process economics can result from the addition of sulphur sources containing valuable by-products, such as nickellcobalt andlor precious metals (gold and PGMs). This is especially true in the latter case, when the HPAL can be operated under Platsol conditions (i.e. with the addition of 5-10g/L of chloride), to dissolve the base metals and precious metals simultaneously in the autoclave. Various examples of the application of this concept are presented, together with a brief discussion of its implication on the autoclave design and the downstream processes to recover the values from the leach solutions. Keywords: limonite, co-treatment, acid consumption, sulphur, sulphur compounds, pressure acid leach (HPAL, PAL), Platsol process

Jan 1, 2004

By S. V. Cherty

The utilization of natural gas in non-ferrous industries during smelting and refining stages of copper , aluminum, zinc and lead was studied. The total amount of nonelectrical energy consumed in the production of zinc, copper, lead and aluminium, are 96.5% ,93%,92%, and 6 % respectively. It is calculated that 9.45 wt %of air of stoichiometric amount can be substituted by natural gas to the total air input in the nonelectrical energy utilization processes. The results showed that the non electrical energy may be substituted to an amount of 71 % ,52 % ,35 % ,32 % ,and 26% ,in the production of lead, aluminium (plates, foils) copper, aluminium, zinc, respectivelly. Similar calculations are carried out in terms of energy in Btu for the total production of non-ferrous metals in the U.S. It shows that 51.866~106 millions of Btu of nonelectrical energy can be substituted by 54.58~106 cu. ft of natural gas. Finally, the substitution of non electrical energy in terms of equivalent coal energy is discussed. 1t is shown that total non electrical energy is equal to 1.852 million tones of coal .If this 1.852 million tones of coal is replaced by natural gas, a total savings of 22.14 million dollars are achieved. The total or partial substitution of coal by the natural gas in the existing industrial processes and modification of redesigning the processes is discussed.

Jan 1, 1993

By F. -Z. Ji

Carbon injection into metallurgical slag is important in electric arc furnace (EAF) steelmaking for foamy slag practices and in nonferrous slag cleaning operations. The current publication presents kinetic data for coal injection into EAF slag to understand the interaction between injected carbon and metallurgical slag. Coal particles were injected into EAF slag and the kinetics were followed by gas and slag analysis. The results were analyzed, in terms of fundamental rate equations for each possible reaction step, as a function of temperature and slag composition.

Jan 1, 2003

By Batric Pesic

Solvent extraction of nickel and cobalt from the real leach solutions was studied by using a novel extraction system. The extraction system was a mixture of 2,6-bis-[5-n-nonylpyrazol-3¬y]] pyridine (BNPP) and dinonylnaphthalene sulfonic acid (DNSSA). The BNPP represents a novel molecule, which was designed and synthesized in our laboratory. Real solutions for the study were prepared by leaching of two different cobalt-nickel bearing concentrates, cobaltite [CoAsS] concentrate from Blackbird Mine, Idaho, and siegenite [(Ni,Co)3S4] concentrate from Missouri Lead-Belt. The major strength of the system was the selectivity of extraction toward nickel and cobalt from iron containing solutions. Other metals such as Mn, Mg, Ca, Al and As were not extracted. Due to the irreversibility of copper extraction, its removal from solution was required prior to the extraction of nickel and cobalt. Zinc was not as strongly extracted (i.e. its stripping was readily achieved) as was copper . Flowsheets for the recovery of nickel and cobalt were also developed.

Jan 1, 1997

By P. Blazy

A hydrometallurgical procedure for the recovery of metal from ore, particularly of copper from sulphide materials is described. In the course of this procedure, the raw material is first of all submitted to the action of an appropriate reducing system and then treated with a ferric salt solution which brings about the selective solubilisation of the elements to be recovered with respect to those constituting the pyritic phase. This procedure is investigated using two ore samples proceeding from massive sulphide deposits, presenting different chemical and mine- ralogical characteristics. The results of this investigation are compared with those obtained by a classical process employing a ferric salt solution. It appears that one solubilisation of copper takes place under particularly advantageous conditions when our procedure is used. The principal parameters affecting leaching of zinc, lead and copper are examined. The selectivity of this treatment is evaluated by following the change during the treatment in the pyritic phase.

Jan 1, 1976

By Chu Yong Cheng

The solvent extraction (SX) processes of the three pressure acid leach (PAL) nickel plants in Western Australia have been reviewed. The use of intermediate precipitation, solids/liquid separation and re-leach in the three W A nickel plants make these processes complicated and costly in capital and ?operation. The research work carried out by the SX group at the AJ Parker Cooperative Research Centre for Hydrometallurgy I CSIRO Minerals has led to the development of direct solvent extraction (DSX) processes to recover and purify nickel and cobalt from leach solutions. The simplicity of the process flowsheets and the expected savings in capital and operating costs are the major advantages of the new DSX processes over the reviewed processes. By using a new synergistic organic system in semi-continuous tests with a pilot plant leach solution (after iron precipitation) from BHP-BiIliton Stainless Steel Materials, the metal values (Ni and Co) together with zinc and copper were separated from the major impurities (Mn, Mg and Ca, together with Cl) in the first SX circuit. The co-extracted manganese, magnesium and' calcium were easily scrubbed out. After stripping, the metal values (Ni and Co) together with zinc and copper were concentrated, resulting in a much smaller second SX circuit and equipment in the down stream processes. The extraction and stripping kinetics of the metals with the new synergistic organic solution were very fast. The extraction and stripping almost reached steady state within 0.5 minutes. Semi-continuous test work with a synthetic leach solution, a cobalt pilot plant leach solution from Peko Rehabilitation Project Pty Ltd and a synthetic solution to simulate a concentrated laterite leach solution from BHP-Billiton Stainless Steel Materials showed that manganese, calcium, copper and zinc can be effectively and efficiently separated from nickel, cobalt and magnesium by extraction, scrubbing and stripping. This led to the development of another DSX process using D2EHPA to recover nickel and cobalt from leach solutions.

Jan 1, 2003

By Chu Yong Cheng

Manganese is one of the main impurities in the recovery of base metals from their ores. This is especially true when laterite ores are processed using the pressure acid leach (PAL) process. The use of intermediate precipitation, solids/liquid separation and re-leach in the three Western Australian nickel laterite plants to separate nickel and cobalt from manganese and other impurities makes these processes complicated and costly in capital and operation. The research work carried out by the solvent extraction (SX) group at the A J Parker Cooperative Research Centre for Hydrometallurgy (CSIRO Minerals) has led to the development of direct solvent extraction processes to separate nickel and cobalt from manganese and other impurities. The simplicity of the process flowsheets and the expected savings in capital and operating costs are the major advantages of the new direct solvent extraction processes over the existing processes. By using a new synergistic organic system, Versatic 10 / dccyl-4-pyridinccarboxylatc ester, with a pilot plant leach solution from BHP¬Billiton (after iron precipitation), the metal values (Ni and Co) together with zinc and copper were separated from manganese and other major impurities (Mg, Ca and Cl) in the first SX circuit. The co-extracted manganese, magnesium and calcium were easily scrubbed out. The extraction and stripping kinetics of the metals with the new synergistic organic system were very fast and the synergistic system was found to be chemically stable. pH-extraction isotherms of metals with D2EHPA showed that the extraction order as a function of pH50 was Zn2+ > Ca2+ > Mn2+ > Cu2+ > Co2+> Ni2+> Mg2+. Semi-continuous test work with a cobalt pilot plant leach solution from Peko Rehabilitation Project Pty Ltd and a synthetic solution to simulate a concentrated laterite leach solution from BHP-Billiton showed that manganese, together with calcium, copper and zinc can be separated from nickel, cobalt and magnesium. This led to the development of another direct solvent extraction process to separate manganese and other impurities from nickel and cobalt and to recover nickel and cobalt from leach solutions. A project was initiated by HiTec Energy Ltd to recover manganese from waste laterite leach solutions using SX technology and to further purify it to produce high purity electrolytic manganese dioxide (EMD) for the high quality alkaline battery industry. Batch tests were conducted to select a suitable organic system for the extraction of manganese in terms of selectivity and extraction and stripping kinetics. A total of eight organic systems were tested using waste laterite processing solutions. A Versatie 10 / synergist system showed very promising results. By using the synergistic system, high manganese recovery would be obtained, fewer SX stages would be required and a higher A:O ratio could be used in extraction, resulting in a smaller organic inventory and lower capital costs. The risk of gypsum formation is also minimised with the synergistic system. Keywords: Solvent Extraction, Manganese, Laterite, Synergist

Jan 1, 2004

By Emil B. Milosavljevic

The photochemical reactions of cyanide ion induced by light were investigated in the presence or absence of a titanium(IV) oxide semiconductor photocatalyst. The light sources employed were the sun and arrays of either mercury or fluorescent (cool white) lamps. The results obtained verify that cyanide decomposes much faster when TiO2 is present in the solution and that it is first oxidized to cyanate. However, contrary to the previous studies, it is established that cyanide is subsequently further oxidized via nitrite all the way to nitrate irrespective of the light source. As expected, the rates of the oxidation processes decrease with the illumination source utilized in the following order: Hg-lamps > sunlight > fluorescent lamps. As nitrate is a significantly less hazardous contaminant than cyanide, complete photocatalytic oxidation of cyanide to nitrate may be a viable method for decontamination of cyanide wastes. Contrary to previous claims, we find that cyanide is slowly photochemically decomposed even in the absence of TiO2. For example, with the mercury lamps as the light source, in two hours, cyanide concentration decreases to essentially zero; up to 7% was converted to cyanate and the remainder to unidentified products.

Jan 1, 1992

By J. A. Sekhar

Solidification processing/casting is increasingly being adopted as the preferred manufacturing technique for the fabrication of net shaped complex geometry components. Modeling of solidification processes is important both for design purposes as well as for understanding the physics of morphological evolution of the solidification microstructure. A fundamental aspect of such modeling involves the precise understanding? of heat transfer through the two phase solid/liquid region. A scheme to do this will be presented where the nonlinearity of the fraction liquid with change in temperature can be incorporated into the numerical calculations. The importance of properly accounting for the non-linear mushy zone will be discussed. Typical processes like squeeze casting and electromagnetic stirring will be discussed to illustrate how precise modeling of the solid/liquid region can aid in the calculation of accurate heat transfer coefficients for these processes.

Jan 1, 1990

By Keiji Okumura, Jiayi Shan, Jian Yang, Masamichi Sano

"A new method of deoxidation and desulfurization of molten iron with magnesium vapor has been developed. An immersion tube, which was filled with pellets of the mixture of magnesia and carbon powders, was put into the molten iron. Magnesium vapor produced by carbothermic reduction of magnesia inside the tube was injected directly into the molten iron with argon carrier gas. The effects of temperature and carrier gas flow rate on deoxidation and desulfurization were investigated. A mathematical model of the reactions was developed. The rates of deoxidation and desulfurization were controlled by mass transfers of magnesium vapor in the gas-phase and oxygen and sulfur in the liquid-phase. This method may offer high efficiency for magnesium deoxidation and desulfurization of molten iron.IntroductionMagnesium is a strong refining agent in steel-making processes1 • At steelmaking temperatures, magnesium has a very low solubility in liquid iron, and a very high vapour pressure2 • Deoxidation and desulfurization with magnesium take place essentially through the interaction of magnesium vapor with oxygen and sulfur dissolved in molten iron, and magnesium can change chemical composition of nonmetallic inclusions3 • However, addition of magnesium to the steel bath is dangerous and does not give high efficiency in the refining process4 • Furthermore, as a refining agent, the price of magnesium is higher than aluminium and CaO fluxes. In the present study, a new method of the deoxidation and desulfurization of molten iron was developed using magnesium vapour in-situ produced by carbothermic reduction of magnesium oxide. Pellets made of mixture of magnesia and carbon powders were charged into an immersion tube, which was made of alumina or graphite. The magnesium vapor was injected directly into the melt. The effects of pellet mass, experimental temperature and carrier gas flow rate were studied on the refining rate. A mathematical model of the refining reaction was proposed on the basis of the experimental results."

Jan 1, 2000

By D. A. Milligan

Ammonia leaching of copper sulfide concentrates, matte, scrap or other sources of copper yields copper amnine sulfate solutions which are converted to metal in a two-stage process involving precipitation of inter- mediate sulfites and their thermal decomposition to copper powder of high purity. Processing details and results are given. Considerable simplification in circuitry and cost savings are indicated. Energy requirements are reduced by substitution of copper powder precipitation and ammonium sulfate crystallization for solvent extraction, electrowinning and lime boil.

Jan 1, 1976

By I. Gaballah

Decontamination of synthetic solutions of copper acetate, chloride, nitrate and sulfate containing 10, 100 and 1000 ppm of copper, using chemically treated barks has been studied. Metal percent removal from solutions depends on the pH and the initial concentration and to some extent on the salt used. It varies from 40 to 99 % of the solution initial metallic ion's content. The maximum retention capacity of the treated bark varies from 31 to 43 mg of Cu per gram of dry modified bark. Bark loaded with copper had been analysed by Scanning Electron Microscopy and lnfra Red spectroscopy. Cu is uniformally distributed in the bulk of the bark. No copper segregation is observed. It seems that copper is bound to the acidic sites of the bark. Anions are not detected on the copper loaded bark neither with the SEM or with the IR spectroscopy.

Jan 1, 1993

By . Menad Gaballah I

Three samples of solid wastes generated by the non ferrous metallurgy were characterized. These residues contain up to 42 % of valuable metal compounds ( Cu, Pb and Zn ) and 23 %of toxic compounds t As, Hg, Cd and Se ). These sample were subjected to thermal treatments between 200 DC and 800 °C in controlled oxidizing. reducing and chlorinating atmospheres. Up to 99 % of As, Cd, Hg and Se were eliminated from these industrial wastes. Cu, Pb, and Zn compounds were concentrated in the treatments' residues of these samples. A Global Decontamination Factor' GDF ' was defined to measure the efficiency of the elimination of toxic elements and the recovery of valuable elements for a specific sample submitted to a given treatment. It seems that the thermal treatment in a reducing atmosphere was the most efficient in decontaminating these solids and the concentration of valuable elements. a.

Jan 1, 1995

By J. J. Moore

The application of plasma technology to process metallurgy is briefly discussed. Experiments involving in-flight reduction of minerals (taconite, chromite, in particular) with a solid-based carbon reductant are described. The resultant metallic and slag product analysis is discussed with respect to thermodynamic and kinetic considerations.

Jan 1, 1985

By Katsutoshi Inoue

The sulfuric acid leaching of spent hydrodesulfurization catalysts yields an acidic solution rich in rare metals such as molybdenum, vanadium, cobalt, and nickel in addition to aluminum. For the purpose of separating and recovering the rare metals from the solution, basic solvent extraction characteristics of the metals involved with commercially available acidic organophosphorus reagents like TR-83, PC-88A, PIA-8 and CYANEX 272 as well as aliphatic alpha-hydroxyoxime LIX 63 from sulfuric acid media were investigated in the present work. It was demonstrated that CYANEX 272, PIA-8 and LIX 63 possessed excellent selectivity for molybdenum and vanadium over the other metals at comparatively low pH. Further, recovery of molybdenum and vanadium from the total leach liquor by the selected extractants was discussed. Additionally, in order to achieve preferential separation and recovery of cobalt and nickel over an appreciable amount of aluminum from the raffinate obtained after recovering molybdenum and vanadium, a systematic investigation was conducted on synergistic extraction behaviors of the mixed solvents of LIX 63 in combination with a series of acidic extractants such as CYANEX 272, PIA-8, PC-88A, D2EHPA, TR-83 and OPEHPA for cobalt, nickel and aluminum. It was elucidated that all of these mixtures could exhibit a good synergistic effect for extraction of cobalt and nickel, and that the lower the pKa of the acidic extractants, the greater the synergism. Contrarily, the extraction of aluminum, was considerably suppressed by LIX 63. Effective extraction of cobalt and nickel away from aluminum was accomplished from the sulfate solution at low pH (1.0 - 2.5) with the mixtures. In particular, the mixtures consisting of LIX 63 and CYANEX 272 or PIA-8 appeared to be the most feasible and economic from an industrial point of view, yielding acceptable separation efficiency for cobalt and nickel over aluminum and .a low acidity requirement for stripping cobalt and nickel as well as negligible degradation of LIX 63. Aluminum can be readily recovered as sulfate salt from the raffinate obtained after recovering molybdenum, vanadium, cobalt and nickel as outlined above by conventional crystallization method.

Jan 1, 1995