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By Marc Verhaege

The effluent under investigation results from a catalic oxidation unit in which paraxylene is oxydised to terephtalic acid. The solution contains cobalt and manganese as their acetates in a concentration range of 0,4 - 1,2 g/I of cobalt and 0,8 - 2,4 g/l of manganese. Before being fed into the main waste stream treatment unit of the plant it is advisable to apply a petreatment step in which both metals are eliminated to a great extent from this effluent. Conventional treatment is done by precipitation of both metals either through pH increment with a base or by adding a suitable reagent producing insoluble species. The aim of this study was to look for a treatment (elimination of both metal species) in which no sludge or precipitate is formed.

Jan 1, 1995

By R. Hurman Eric

The electrode in a slag-resistance electric furnace is the central factor in the design and operation of the furnace by its role of conveying the smelting power, i.e. heat needed for the operation. The control parameters are the size and positioning in the slag bath which are defined by slag resistivity, furnace resistance, cell constant and power input sequence all of which are closely interrelated. The flow of heat generated by the electrode current determines the energy distributions and thus the furnace dimensions. Heat flow models concerning vertical, horizontal and combined two-dimensional flows are discussed. All these considerations are based on the experimentally determined slag properties such as its resistivity.

Jan 1, 1995

By J. F. White

An experimental study was undertaken to evaluate the feasibility of a selective chloridizing roasting pre?treatment process for the elimination of impurities from zinc feed?stocks prior to recovering zinc by conventional unit operations. In this investigation, a number of chemistries that might serve as a basis for such a pre? treatment process were examined. A variety of chloridizing agents were admixed with EAF dust to promote the selective removal of lead and cadmium by the formation of volatile metal chlorides, he results of the experimentation firmly establish that selective chloridizing roasting is a technically feasible means of eliminating lead and cadmium from EAF dust. Excellent extraction efficiencies were accomplished with a number of chloride additives; as high as 98 percent lead extraction and 88 percent cadmium extraction were attained with minimal zinc losses, Continuous pilot?scale tests reinforced the trends established by laboratory?scale experimentation, Attempts of chlorine elimination using pyrohydrolysis were less successful. The extent of chlorine elimination was found to be highly dependent upon EAF dust sample type and treatment temperature.

Jan 1, 1996

By E. Morrice

Solubility of yttrium oxide (Y203) in fluoride melts was experimentally measured in the temperature range of 998 to 1273 K and, YF3 composition in LiF.YF3 melts varying from 20 to 50 mole pct using a graphite crucible in an argon atmosphere. Solubility of oxide in the melt was found to increase with increasing temperature and YF3 composition in the melt. An expression for in XY2O3 as a function of temperature for several melts was deduced. The calculated activity coefficients of Y2O3 in the melts exhibited a negative deviation from Raoult's law.

Jan 1, 1989

By Jing Zhan, Tian-zu Yang, Wei-feng Li, Li-Hua Jiang, Shi-yan Xu, Jian-yang Huang, Chuan-fu Zhang, Yan-qing Fan

The amount and activity of coal, reduction temperature and other parameters of the process of bottom-blown reduction of liquid high lead slag were investigated in laboratory. Methods to strengthen the bottom-blown reduction process were studied by industrial production. The results were in the follows: the reduction temperature was 1150℃; reduction time was 1.5h; the reductant was anthracite; lead content in slag was controlled to 2%; the rate of coal was 7% and gasification loss of coal in high temperature was severe; liquid lead slag reduction rate was faster with coal; prolonging the reaction size had little effect on reducing lead in slag; the size of the reactor can be further reduced.

Jan 1, 2015

By Ross R. Bhappu

A theoretical and experimental investigation into pyrometallurgical refining of chloride leach/electrowin copper is described. The two techniques investigated were (i) vaporization and (ii) gaseous halogenation. Experiments were carried out with a packed bed of electrowon copper crystals and a boat of melted copper crystals. Nitrogen gas and Freon 12/nitrogen mixtures were used as the carrier and reac.tive gases. Vaporization was found to be effective in removing Bi, Pb and S while halogenation was effective. in removing As, Bi, Pb, S and Sb. Silver resisted all attempts at removal. Iron was removed but less effectively than the other impurities.

Jan 1, 1985

By H. Kaffash

Ferromanganese is a ferroalloy with high manganese content which finds many uses for example as deoxidizer in steelmaking industry. However, there is very little data on the dissolution rate of carbonaceous materials in Mn containing metals. In this paper, the kinetic analysis of carburization reactions is investigated for Mn–Fe alloys. Dissolution rate of graphite in pure iron and four different alloys with 10 wt%, 40 wt%, 60 wt% and 85 wt% manganese at 1823 K was studied. Results showed that the dissolution rate of carbon from graphite increased with increasing time for all alloys. The dissolution rate constant increased with the increasing manganese content from 6.5 × 10−3 cm/s for 0%Mn to 23.6 × 10−3 cm/s for 85%Mn.

By I. A. H. Schneiderl

Eichhornia crassipes approaches being a scourge in many parts of the world, .choking waterways and hindering transport upon them. At the same time it is known to readily abstract heavy metal ions from water and, thus, aids in the removal of heavy metals found in such waters. This paper considers the possibility of using specific parts of the plant as an inexpensive adsorbent for the removal of heavy metals from contaminated chemical and mining industry waste waters. In particular the root of the plant was found to be an excellent accumulator of 'heavy metal ions including uranium from solution. It is. also suggested that dried roots of the plant ?might be placed in simple bags and used in a very low cost metal ion removal system.

Jan 1, 1995

By Yang Guangqing, Shao Jiugang, Zhang Jianliang, Wan Dan, Fu Yuandi, Guo Hongwei

"Resource of metallurgical coke is becoming scarce, and although coke can be partially replaced by pulverized coal injection, there are many restrictions for further increase in coal ratio. Mixed charge of ore and lump coal from top to replace more coke was studied in this paper. Softening-melting property of the burden was affected by charge of lump coal. Softening-melting properties of mixed charge of ore and coke, mixed charge of ore and lump coal were tested respectively. Results show: the property of the burden mixed with coke is superior to the burden mixed with lump coal; lump coal would not deteriorate softening-melting property of the burden and some of them can even improve softening-melting property of the burden. Top charge of lump coal would not deteriorate softening-melting process, and this should be a new way to increase coal consumption to decrease coke rate.IntroductionThe blast furnace is still the predominant process for the reduction of iron ore and will probably remain so for the next decades. Metallurgical coke is becoming scarce and expensive, so the cost of hot metal can be decreased by reducing the consumption of metallurgical coke[l]. Coke can be partially replaced by pulverized coal injection, currently the highest rate of pulverized coal reached 266kg/tHM, most of blast furnace PCR is about 150kg/tHM, and it is very difficult to further increase of PCR. Nut coke is charged into blast furnace mixed with iron ore, not only for improving utilization of metallurgical coke, but also for lowering the coke rate. Presently the majority of blast furnaces in the world use nut coke although its amount is very different: from 10-20 to 70--100 kg/tHM and more[2-4].The effect ofnut coke in blast furnace is extensively researched, and the main conclusions recommend: to improve gas permeability of cohesive layer in blast furnace, to promote reduction of iron burden, protect metallurgical coke from the solution in the shaft due to higher reactivity of nut coke. There is no special requirement for the strength of nut coke[5-8]. Nut coke is also used for sintering fuel, which may lead to the shortage of the nut coke charging into blast furnace. So lump coal mixed with iron ore is considered to be charged into the blast furnace, not only to reduce the cost of grinding coal, but also to increase the use amount of coal."

Jan 1, 2013

By Matthias Merzkirch, Volker Schulze, Kay Andre Weidenmann

"Unidirectionally reinforced light weight compounds based on light metals such as the aluminium alloy EN A W-6082 are adequate materials for the future use in transportation means like automobiles and airplanes. Due to the occurring cyclic loads knowledge about the crack growth behaviour of such composites is needed. The investigations at a load ratio of R = 0.18 show that the crack growth rate of the aluminium matrix is reduced if reinforced by spring steel wire with a reinforcing ratio of only about 1 Vol.-%. Additionally, the acoustic emission analysis allows detecting crack growth within the matrix material, crack propagation along the interface wire/matrix and crack closure which could also be determined with the help of a self designed capacitive displacement measuring gauge. The damage behaviour could be verified by metallographic and SEM investigations.IntroductionIn the field of lightweight structures for transportation means the need for light, strong and stiff materials, in particular composite materials, is increasing in order to save resources and costs. Lightweight materials such as aluminium and magnesium alloys are highly efficient candidates to be used in the composite extrusion process [1] which allows for a simple production of unidirectionally reinforced profiles with a large diversity of geometries at low costs. Figure 1 depicts the principle of the composite extrusion process; within the first part of the tool the billet material is split into several strands whereas the middle part of the tool allows the supply of the reinforcing elements. The third part of the tool rejoins the matrix material and the reinforcing elements and defines the final shape of the profile."

Jan 1, 2011

By R. C. Hubli

A chemical model has been developed to investigate the dissolution of sulphide minerals in brine solutions containing copper and iron chlorides. The model has been employed to study the dissolution .of synthetic NiS using different initial concentrations of Cu(II), Cu(I), Fe(III) and temperature. The speciation of copper with particular reference to the formation of hydroxy-chlorides as a function of total chloride and H+ has been computed. The model predictions are in agreement with experimental results. It has been found that addition of Fe(III) results in the maintenance of a high Cu(II)/Cu(I) ratio leading to enhanced rates of dissolution and suppresses the loss of Cu(II) due to the formation of hydroxyl-complexes.

Jan 1, 1997

By Masayuki Kudoh, Tohru Maruyama, Yohichi. Ito

When hypo-peritectic carbon steel is quenched during unidirectional solidification, the region of fine columnar grain is observed. It is classified into two coexisting phases. One is coexisting phases of liquid, delta and gamma in the upper part of the region, and the other is coexisting phases of delta and gamma in the lower part of the region. To form the coexisting part of the three phases means that solidification in this experiment proceeds in non-equilibrium state. The size of the narrow side of one fine columnar grain coincides with the arm spacing of a primary dendrite and this result is the same as the hyper-peritectic carbon steel. However, the boundary of the fine grain in the hypo-peritectic carbon steel is formed in different location from that of the hyper-peritectic carbon steel. The former is formed in the skeleton of the dendrite, while the latter is formed in the interspacing of the dendrite. The region of the fine grain changes suddenly to that of the coarse grain when the delta phase in the coexisting part of two phases disappears completely. Therefore, the delta phase in the hypo-peritectic carbon steel might prevent the growth of gamma grain. In order to recognize it, ferrite formers such as Mo, V and Ni are added in the sample. Then, the longitudinal length of the fine columnar grain extends in the sequence of the no addition, Mo, V and Nb.

Jan 1, 2000

By Gerhard Bayer

X-ray and thermoanalytical studies were carried out on the formation and stability of Ca-, Mg-and Mn-tungstate, and of the corresponding minerals scheelite and wolframite. The tungstates were synthesized by different methods: precipitation from solution, solid state reactions, displacement reactions with solutions and in the solid state. The reactivity of natural scheelite and wolframite with different salt solutions and in mixtures with other minerals was investigated.

Jan 1, 1989

By C. -S. Jiang

In most copper refineries, addition agents are added at predetermined rates with no further monitoring of their activity or concentration in the electrolyte. Increasingly stringent cathode quality requirements, and a desire for better process control in tankhouse operations, have recently directed a number of refineries to search for a better addition agent control strategy. Extensive development work has been carried out at the Noranda Technology Centre for the monitor in of glue and thiourea in copper refinery electrolyte using cyclic voltammetry (cv~. Data from both synthetrc and commercial electrolytes are presented, showing the ability of CV to produce reliable and easily identifiable fingerprints of addition agent concentrations in copper refinery electrolyte.

Jan 1, 1991

By Neusa Alonso-Falleiros, Aristeu Braz da Veiga, Marcelo B. Mourão, Adriano Pescarmona, Antonio Alberto Froes Schettino, Cyro Takano, Carlos A. S. Giraldo

"The Caron process of nickel extraction from lateritic ores produces a fair amount of an inert residue, the so-called “black sludge”, that is disposed in a dam according to the required environmental regulations. On the other hand, it represents an opportunity to resource recovery. This work presents the characterization of the residue, discusses some possible ways to recover the valuables, and presents experimental results of pyrometallurgical runs aimed at recover nickel as an iron-nickel alloy. It has been shown that the residue contains large amounts of silicon, iron, aluminum and magnesium, in the form of oxides and silicates, and small quantities of nickel, cooper and cobalt, besides several other elements. It has also been shown that gravimetric or magnetic concentration methods do not present promising results. On the other hand, it is possible to obtain iron-nickel alloys by high-temperature carbothermic reduction of the “black sludge”.IntroductionThe Caron process consists of a combined pyro-hydrometallurgical process to extract nickel from high iron limonitic lateritic ores, recovering also the cobalt present in the ore. The main steps are the reduction roasting of the ore, aiming at a selective reduction of nickel and cobalt to the metallic state, avoiding as much as possible iron reduction, followed by leaching with ammonium carbonate solution and the recovery of metal from the pregnant liquor [1,2]. As a result, significant amount of tailings are generated, that are disposed in appropriate dams. This residue, called “black sludge”, contains significant proportion of silica and iron, and also small amounts of nickel, cobalt, cooper and some other elements. Due to diminishing deposits of nickel ore, high metal prices and a significant amount of “black sludge “ available after several years of operation of the plant, Votorantim Metais, who operates a facility in Brazil that uses the Caron process, decided to explore the possibility of recover nickel from the residue. This paper presents the characterization of the residue, and the results of experimental work aiming recovery of nickel from it."

Jan 1, 2008

By Guangwei Wang, Changle Zheng, Yifan Chai, Jian Guo, Weiwei Geng, Jianliang Zhang

In this paper, characteristic and kinetics of CO2 reaction with four different kinds of coke such as top-loading coke, dry quenching tamping coke, wet quenching tamping coke and semi-coke were investigated based on isothermal method. Electric resistance reduction furnace was used to heat the sample. Volume Model (VM) and Shrinking Core Model (SCM) were used to calculate the kinetic parameters and to contrast with the experimental results. The results showed that the Volumetric Model (VM) was much suitable for the reaction of top-loading coke, dry quenching tamping coke and wet quenching tamping coke, while Shrinking Core Model (SCM) was much suitable for semi-coke.

Jan 1, 2015

By Klas G. Hultbom

Mercury is present as trace contaminant in many raw materials for metallurgical plants. When such materials are treated with pyrometallurgical processes the mercury is volatilised. Mercury has a high vapour pressure, even at low temperatures, and therefore it is removed only partly by normal gas cleaning processes. The Boliden Norzink scrubbing process removes elemental mercury by converting it to calomel. It is widely used in the base metals industry. This paper gives examples of the application, and also outlines the background for the development of the process. Another technology developed by Boliden for mercury removal is the Selenium filter. This is a fixed bed filter based on the reaction between elemental gaseous mercury and selenium, by which mercury selenide, HgSe, is formed. The mercury selenide is a highly stable compound with extremely low solubility in water and very low vapour pressure. Mercury is removed selectively without any side reactions. Special applications for the selenium filter technology include mercury removal from gases containing sulphur dioxide and geothermal off-gases.

Jan 1, 2003

By Wing Ka Ng

Substitution of pulverized coal injection by solid biocarbon fuel has the potential to achieve substantial reduction in GHG emissions associated with blast furnace ironmaking. A systematic evaluation was conducted on the performance of solid bio-carbons produced from a single raw biomass source using different pyrolysis technologies. The potential of solid biocarbon in reducing GHG emission of the blast furnace ironmaking process is strongly influenced by its O/C mass ratio. In order to achieve substantial GHG reduction, it is necessary to replace coal injection by solid biocarbon having a low O/C mass ratio. The pyrolysis technology and conditions employed are key parameters influencing O/C mass ratio of the resultant solid biocarbon. Close collaboration between steelmakers and solid biocarbon producers is critical for producing suitable solid biocarbon fuel to replace pulverized coal injection. A successful partnership should pave the way in achieving substantial reduction in GHG emissions of the blast furnace ironmaking process.

By Animesh Jha

The carbothermic reduction of chalcopyrite has been studied in the temperature range 1073 to 1273K in presence of lime. The role of lime during the reduction process is explained and the phase equilibria leading to the metallisation of copper and iron are discussed. The effect of coal and carbon monoxide on the reduction process have been studied and the rate governing steps are identified. This investigation also cites examples of possible mechanisms of physical separation of metallic Cu from iron during the reduction process.

Jan 1, 1992

By R. Hurman Eric

The flow of molten slag and matte and the estimation of the mass of settled matte in electric furnaces is discussed and the action of the electric furnace as a settler is considered. Particle size of the concentrate and its grade are major contributors to settler dimensions. Discussion on the production capacity of the electric furnace with reference to operating current, power input, furnace dimensions such as width and length and electrode diameter are given. These discussions are based on considerations derived mainly from experimentally determined properties of the slag such as its resistivity, viscosity and liquidus temperature. Extension of the design and operating considerations to circular furnace symmetry is also discussed.

Jan 1, 1995