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By Zhigan Deng

Cooling crystallization was used to separate iron (III) and nickel (II) from acidic sulfate solution produced by leaching of molybdenum-nickel black shale. The effect of K2SO4 concentration, crystallization temperature, solution pH and crystallization time on recovery of nickel (II) and precipitation of iron (III) was investigated, in order to obtain effective separation of nickel and iron. The optimum parameters determined were as follows: 200 g/L K2SO4, 10 °C crystallization temperature, solution pH of 0.5 and 24 h crystallization. Under these conditions, 97.6% nickel (II) was recovered as K2Ni(SO4)2, 6H2O crystals and only 2.0% of the total iron (III) was precipitated. Recrystallization yielded K2Ni(SO4)2, 6H2O crystals with a purity of 98.4%.

By R. C. Nascimento

It was investigated the effect of the addition of bentonite on the physical propertiesof pellets produced from fines of manganese ores. Cold-bonded pellets were produced. Pellets bearing up to 1 wt% of bentonite were submitted to strength compression resistance tests, fatigue of pellets to impact and maximum height of fall tests. A correlation of resistance of the pellets and time for curing were stablished. The produced pellets match the conditions for raw materials used in electric smelting hrnaces to produce manganese based ferro-alloys.

Jan 1, 1995

By Zhang-Guang Gao, Ming-Mei Zhu, Rui-Rui Zhao, Chao Jiang

This paper focuses on the CaO-SiO2-FeO-MgO-MnO-P2O5 slag system that represents the major components of dephosphorization slag in BOF. Phosphorus distribution between 2CaOSiO2-3CaOP2O5 Solid Solution and Liquid Slag were analyzed by FactSage. The effects of slag content, basicity on the distribution ratio of P between the solid solution phase and the liquid phase (LP) and the percentage content of P in solid solution phase and liquid phase have been discussed. The results show that, with the increase of basicity, LP (wt%) decreases until the basicity reaches 1.9, then it turns to increase. LP (wt%) increases gradually with the increasing amount of FeO or P2O5.

Mar 1, 2017

By Varadarajan Seshadri

A physical model based on similarity principles was constructed for simulating the RH degasser of CST (Companhia Siderurgica Tubarao, Vitoria, ES, Brazil) to evaluate the circulation rate of the metal which essentially defines the degree of exposure of the metal to vacuum in the chamber and thus of the refining rate, The circulation rate on the other hand will influence the decarburization rate and removal of dissolved gases like nitrogen and hence it is essential to optimise this parameter to get maximum refining efficiency with minimum refining times, thus improving the productivity of the secondary refining process. Mixing characteristics in the ladle is evaluated by pulse tracer addition using conductivity-meters located at the down leg as well as at several locations in the ladle. The influence of gas injection through nozzles in the upleg with simultaneous bottom injection of gas as well as nozzle blockage on the circulation rates were investigated. Also simulation experiments of kinetics of decarburization were carried out using CO2 adsorption-desorption process in sodium hydroxide solution as circulating fluid and the effect of, bottom gas flow rate in this case was also evaluated. The results were carried over to prototype and to optimize the process.

Jan 1, 2003

By C. Cánepa

In the treatment of many problems related with the optimization of a given ore dressing process, microscopic studies can provide invaluable assistance. Such studies are generally carried out through mineralogical determinations both qualitatively and quantitatively. Frequently the solution of a specific problem requires the combination of these in adequate proportions. Often the nature? of the problem poses some conditions regarding the way the microscopic determinations are made in order to yield useful information. Most publications applied to mineral beneficiation show results of ore microscopy without mentioning the methodological details involved in the determinative work and therefore it is not possible to judge their reliability and/or their relevance. As methodology must necessarily change from case to case, it is very important for the microscopist to identify first the direct and indirect mineralogical information required to solve the problem. Without such guidelines selection of methods for the qualitative and/or quantitative determinations cannot be made.

Jan 1, 1981

By D. W. Ashman

The zinc pressure leaching plant at Cominco's Trail Operations is now in its ninth year of production. The plant produces a zinc sulphate and jarosite slurry which is further processed in the calcine leaching circuit. Elemental sulphur, a by-product of the process, is sold in the North American market. During the past eight years, a number of changes have been made to the plant to remove known production bottlenecks and to improve leaching extraction. These changes have raised production rates above the initial design so that the plant currently accounts for approximately 20 percent of Trail s zinc production. These rates are expected to be increased further upon the completion of the alterations currently in progress. The knowledge gained over the operating life of this plant has allowed Cominco to plan for a possible future expansion of the zinc pressure leaching plant. If expanded, zinc pressure leaching would account for approximately 48 percent of cominco?s zinc production.

Jan 1, 1990

By Cristián Araya L.

A dynamic agglomeration, heap leaching, solvent extraction and electrowinning software, called NICO, has been developed in order to either design or simulate copper ore recovery plants. NICO contains a library of routines, each representing a unit operation or piece of equipment, which are assembled like a meccano to match almost any wet plant configuration. Routines include agglomeration or curing either in drums or belts, belt conveyors, heap stacking and reclaiming, heap leaching of oxide, sulfide or mixed copper ores, heap irrigation, drainage, ponds, mixer-settlers, filters, columns, coalescers, tanks, electrowinning cells, pumps, and all connections and related piping. All models are semi- phenomenological, i.e., they include all physical-chemical, mass, thermal, transport equations, which are required to represent as closely as possible the equipment or unit operation. However, operating experience has been incorporated into the model in order to make it simpler, faster and reliable. This experience has been tested in several plants in Chile since 1992. Site meteorological data is simulated also; in this way the model is responsive to weather conditions (temperature, solar radiation, ambient humidity, atmospheric pressure, wind velocity, etc). NICO has been used recently for design and optimization studies in copper plants in Chile like Radomiro Tomic, Collahuasi and Zaldivar. A user-friendly interface allows fast and comprehensive simulations. The entire plant is shown in a single graphic screen, so the user can see all the relevant information, and soft-keys are provided in order to change parameters on-line and watch their effect in final copper production in cathodes. Model also calculates and reports operating parameters, as well as estimated investments and operating costs.

Jan 1, 1999

By Rivera Jose Antonio Ore

Top Submerged Lance (TSL) smelting technology is currently used in a wide range of applications in the non ferrous and waste product treatment industries. The use of TSL technology for tin concentrates smelting has been successfully applied at the Minsur Tin Smelter and Refinery at Pisco, Perú. The process is based on the air-cooled top entry submerged Sirosmelt lance, developed by Dr. John Floyd at the CSIRO division of Mineral and Process Engineering in the 1970?s. Advantages of the process include flexibility to operate the lance, main burner of the Sirosmelt furnace, with different levels of combustion stoichiometry which allows us to get from highly reducing to highly oxydising atmospheres in the smelting reactor according to the type of feed we are processing, ability to utilize cheap energy sources such as natural gas, low capital cost and an environmentally friendly operation. This presentation summarises the application of the Submerged Sirosmelt technology for smelting tin concentrates and a variety of tin containing materials like iron dross, copper dross, tin residues, low tin/antimony slags by applying recent metallurgical developments at the Minsur smelter. The impact of new feed conditions and level of impurities on reactor performance with features of process and operation control are described. As a result of these recent advances in tin smelting using TSL technology, the Minsur Tin Smelter and Refinery improved its overall tin recovery, substantially reduced tin inventories and became the second largest tin smelter in the world, currently producing more than 40,000 metric tones of refined tin per year.

Jan 1, 2006

By Zhang Hanbo, Niu Liping, Zhang Zhiqi, He Jicheng, Dou Zhihe

"Rutile, ilmenite and Al-Ca complex reducer were used to prepare high titanium ferrous alloy by enhanced reduction-SHS method. The effects of the complex reducer compositions and slag types on the enhanced reduction-SHS process were investigated. The high titanium ferrous alloys were characterized by XRD and SEM. The results indicate that the high titanium ferrous alloys consist mainly of TiFe2, AlTi3 and Al2O3. The oxide inclusions exist resulting in directly the high oxygen content and micro-structural defects in the alloys. The titanium and oxygen contents decrease, but the aluminum content in the alloy increases while the mass ratio of calcium in the Al-Ca complex reducers increases. When the mass ratio of Al/Ca in the Al-Ca complex reducer is 6:1, titanium, oxygen and aluminum contents are 63.75%, 3.01% and 10.72% respectively. When the mass ratio of Al/Ca is 5:1 titanium content is 55.00% nearly and aluminum content is higher than 14.00%, but oxygen content is lower than 2.0%.1. IntroductionThe high titanium ferroalloys with 65%~75% titanium have the advantages of low melting point and high titanium content. They are widely used in special steel refining, while they are also a kind of very important quality orientation alloys in the rage of aviation and aerospace. At present, the methods of preparing high titanium ferroalloy include vacuum remelting and thermit reduction. The alloys prepared by the vacuum remelting method have good qualities and low oxygen content, so it is widely used in Russia, Western Europe and other developed countries. In China, there are abundant rutile resources, but waste titanium is lack, therefore, the preparation method is the thermit reduction. But there are many quality defects in the high ferrotitanium alloy, including high oxygen content, unstable quality and so on. In order to improve the qualities of the high titanium ferroalloy, especially to reduce oxygen content, the domestic and overseas have done a lot of further researches. For example, Sichuan E-mei ferroalloy plant and Beijing Nonferrous Metal Research Institute have prepared high titanium ferrous with 73.77% titanium with natural rutile, but the oxygen content is high. Through controlling the quality of raw material, they obtained the better qualities, but the oxygen content is still very high. South Africa Mintek company have prepared high titanium ferrous alloy with low nitrate by plasma heating under the isolation air conditions, but they couldn’t also remove effectively oxygen in the alloy. The oxygen exists in the form of Al2O3 and titanium protoxide. So it can be speculated that except TiO2 not being fully reduced, the no-sufficient alloy-slag separation is the direct reason resulting in high oxygen and poor microstructure. In view of present technical difficulties during preparing high titanium ferroalloy by thermit reduction, this paper proposed a new method of preparing high titanium ferrous with low oxygen by enhanced reduction-SHS with Al-Ca complex reducer. Ca in Al-Ca complex reducer has stronger reductive ability, it can effectively strengthen the reductive degree of TiO2. The slagging agent CaO CaF2 and MgO can effectively reduce the viscosity of Al2O3 slag to improve its liquidities to strengthen alloy-slag separation effects so that to remove inclusions and oxygen. In this paper, effects of slagging agent type on the reduction and the qualities of high-titanium ferroalloy were studied."

Jan 1, 2012

By Tapio Ahokainen

Commercial modeling software and increasingly efficient computers enable today computational fluid dynamics (CFD) to be used as a tool for a more comprehensive understanding of the flash smelting and flash converting processes. CFD modeling can be used for design purposes in many technological areas, but some relevant physical and chemical phenomena are still missing in the commercial CFD solver packages. Therefore, Outokumpu has developed several subroutines for solvers to describe analytically the phenomena in the flash smelting environment. CFD sub-models of the copper concentrate and matte combustion, the particle-particle-wall interactions and for more accurate radiation properties of the gas-particle suspension are needed to ensure reliability of numerical simulations on the flash smelting and converting vessels. Several basic combustion phenomena can be modeled with a number of commercial solver packages, but own models for combustion must be included in the case of sulfides as the feed. Mathematical models for copper concentrate and solid matte combustion have been developed during the last decade. They calculate compositions of the particles and temperature, based on extensive experimental research work in laboratory scale furnaces with validated kinetic parameters and temperature measurements of reacting particles. Inside and near the concentrate burner, the standard particle tracking methods do not include the particle-particle interactions and the particle-wall interaction is too much simplified to describe properly the particle collisions with the distribution cone. Therefore, additional models for the particle-particle as well as particle-wall interactions have been written and implemented. For thermal radiation, models for the emissivity of a gas mixture and for calculating the particle absorption and scattering coefficients have been developed and tested. In addition, the advanced radiation model can be used i.e. in the enhanced simulation of off-gas cooling in the heat recovery boiler area of the flash smelter.

Jan 1, 2006

By Liugen Sun, Xingming Jiang, Weijiao Yang, Yihang Hu, Yongqiang Yang, Hua Wang

During the past decades, cyclone electrowinning (CE) has been regarded as a novel separation technology, which can be used for direct electrowinning of metals from low concentration solution. Recently, CE was proven effective for the treatment of antimonic gold concentrates. The experimental results of cyclone electrowinning of antimony show the current efficiency increases from 43.8 to 72.2% with the increasing current density (from 254.8 to 647.3 A/m2), and on the other hand, power consumption per ton antimony decreases from 6100 to 4200 kWh with the aforementioned increasing current density. The grade of the obtained cathode antimony could reach 98.6%. Compared with the traditional electrowinning using parallel-board electrodes, the economic profit of CE was 33.1% higher attributed to the high current efficiency of CE. In addition, CE could adapt to high current density. All these characteristics indicate the CE method can be implemented commercially for processing antimonic gold concentrates.

Mar 1, 2018

By Karl A. Gschneidner

The magnetocaloric effect has been known for 120 years and has been utilized for cooling about 70 years. But in the last four years significant advances have been made to show that magnetic refrigeration is a viable and competitive cooling technology. Most of the work has focused on reciprocating devices, but rotary apparati are being developed. To date the magnetocaloric properties have been characterized for more than 200 materials. The magnetocaloric effect behaviors have been classified into three types of behaviors. The most common one is found in magnetic materials which exhibit a second order magnetic phase transition. Magnetic materials which exhibit a first order magnetic phase transition account for the second group of materials. Materials which exhibit multi-magnetic phase transitions make up the third group. The best candidate materials for magnetic cooling over the range from -4 to -1 350 K are also presented.

Jan 1, 2002

By P. Halsall

Smelters of medium or low grade tin concentrates must recover a high proportion of tin from iron-bearing slags or concentrates; the volatility of tin sulphide makes possible the production of iron-free tin fume. Laboratory work defined conditions which would promote the sulphidisation of tin slags and concentrates melted with them, to result in tin recovery as fume, and a residue of less than 0.5% Sn content, which could be controlled to vary with the value of tin. Subsequently pilot-plant work on 6-tonne and 15-tonne scale led to a commercial plant of 45 tonne. capacity (1962), for melting and fuming primary and secondary low-grade tin materials by submerged combustion. Some factors contributing to the rate of Working expressed in terms of the 'half-life and the amount of work done, the 'half-life-tonne' are studied, leading to the design and operation (1972) of the 100-tonne water-jacketed unit, presently in use, treating a wide range of slags and low tin-content ores and residues.

Jan 1, 1983

By Jing Lin, Yuan Xu, Qingcai Liu, Dengfu Cheng

"Smelting reduction technology has been developed greatly in recent years. But one of the key problems for this technology is about the refractory that used as lining material in the molten bath. Investigation and test shown that corrosion rate of refractory was much higher and the corrosion mechanism was much more complexity in the molten bath of smelting reduction with iron bath than that of the blast furnace and rotary furnace technology [l-5]. The corrosion behavior and corrosion rate of Al2OrC-ZrO2 series refractory in the melt of smelting reduction with iron bath have been studied by rotary immersion and quasi-static immersion test in this paper. The major factors that affect the interaction between the melt and refractory were investigated. The test results shown that the corrosion rate of AI2O 3-C-ZrO2 series refractory decreased with the ZrO2 increasing when ZrO2 content was from 3% to 10%. Ferrous oxides content, relative moving speed between the melt and refractory and temperature of the molten bath were the important factors that affect the corrosion rate. But the ferrous oxides concentration was the most important one. The corrosion rate was increased as a linear relation with the rising of ferrous oxides content of the melt. The corrosion rate in the quasi-static immersion was much less than that of the dynamic immersion (rotary immersion) for the Al2O 3-CZrO2 series refractory in the same testing condition. The corrosion mechanism of Al2OrC-ZrO2 series refractory is: graphite oxidized in advance, then interaction between the constituents of refractory and melt taken place and deteriorate layer of refractory and new compounds were formed, the properties of refractory was changed.IntroductionSmelting reduction with iron bath is a typical technology [3, 4, 6]. The obvious features of the melt for smelting reduction technology with iron bath are much higher ferrous oxides and much more complexity melt composition and structure than that of the blast furnace technology [2, 5-8]. The properties of the melt were changed dynamicilly and constantly in reduction process. On the other hand, the behavior of the melt depends on the activity and the reduction rate of ferrous oxides in the molten bath[9]. Because of the high concentration of ferrous oxides in slag and high reduction rate in the molten bath, the corrosion behavior and corrosion mechanism of the refractory lining by melt are an important factor in development of the technology of smelting reduction with iron bath. Up to now, improving refractory quality to anti-corrosion of melt and developing high quality and long term refractory used as the lining refractory materials in the molten bath of the final reduction furnace are also the most important questions for developing smelting reduction technology."

Jan 1, 2000

By Maryam Ghodrat, Bijan Samali

Treatment of polymer-based wastes has a tremendous potential for generating alternative energy, reducing greenhouse gas emissions, creating economic and environmental benefits, and achieving a sustainable development of the energy sector. During the past few decades, plastic waste generation increased at a greater rate than the population, with the move towards single-use products. Also with raising the cost of oil-based products, greater emphasis should be placed upon the usage of plastic/polymer in the waste stream as a supplementary source of fuel. This study presents a techno-economic analysis of the recycling potential of plastic waste in Australia by evaluating the possible use of these wastes as a reductant in steel making incinerators. The study tries to shed light on a possible cost effective alternative route in the smart treatment of waste plastic in Australia.

Mar 1, 2018

By M. Friák, L. G. Wang, M. Šob, V. Vitek

"The paper gives an account of applications of quantum-mechanical (first-principles) electronic structure calculations to the problem of theoretical tensile strength in metals and intermetallics. First, we briefly describe the way of simulating the tensile test and the electronic structure calculational method. Our approach is then illustrated on calculations of theoretical tensile strength in W, NiAl and transition metal disilicides MoSi2 and WSi2 with C11b structure. In Wand NiAl, we consider uniaxial tension along [001] and [111] directions. Although tungsten is elastically nearly isotropic (C44 = C”), theoretical tensile strength exhibits a marked anisotropy (oth/001 = 29 GPa, o'th/111 = 40 GPa). Calculated results compare favorably with experimental value of 24.7±3.6 GPa obtained for tungsten whiskers grown along the [110] direction. Similarly, in NiAl, the 'hard' orientation [001] differs very significantly from the [ill] orientation (oth/001 = 46 GPa, oth/111 = 25 GPa). This anisotropy is explained in terms of higher-symmetry structures present or absent on the calculated deformation paths. In disilicides, the theoretical strength is calculated for [001] loading (oth/001 = 37 GPa and 38 GPa for MoSi2 and WSi2 , respectively). The role of relaxation of internal structure parameter is discussed and changes in bonding conditions during the tensile test are analyzed.IntroductionIn most engineering applications, the strength of materials is limited by the presence of internal defects. If there were no defects, then, for example, the tensile strength could be several orders of magnitude higher and its value would be comparable with that of shear modulus. Therefore, the strength of ideal (defect-free) crystal represents an upper limit of attainable stresses, which is called the ideal strength. While it may not be possible to achieve the ideal strength in practice, it is not possible to exceed it. However, the ideal strength is already approached in situations which are technologically relevant. These include the low-temperature deformation of inherently strong materials, such as diamond, Si, Ge and some of the transition-metal carbonitrides, deformation of whiskers, nanoindentation of materials with low defect densities, hardened thin films and coatings etc. The ideal strength sets the limits of elastic stability of a solid. Its knowledge is useful for estimation of the ideal work of fracture stresses needed for homogeneous nucleation of dislocations and for modelling of crack propagation."

Jan 1, 2001

By De-qing Zhu, Feng Zhang, Jian Pan

Sintering performance of a series of sinter blends with high ratio of limonite was investigated. The metallurgical performance and mineralogy of product sinter were also examined. The results show that good sintering performance could be obtained when the ratio of limonite was below 43% in the blends of iron ore fines, while good microstructure and metallurgical properties were achieved under optimum sintering conditions. In contrast, sintering performance will rapidly deteriorate when the ratio of limonite is elevated up to 63% in the blends.

Mar 1, 2017

By Beatryz C. Mendes, Henrique de Paula Santos, Kléos M. L. Cesar, Eduardo Antônio G. Marques, Maurício Paulo F. Fontes, Rita de Cássia S. S. Alvarenga

Inadequate discard of industrial solid waste is a risk to human health and to the environment. Aiming at softening environmental damage caused by deposition on soil of an ink residue, from washing of printers used in carton box packages, it is intended to incorporate this residue into soil-cement bricks. The residue has other use potentialities such as in screeds, pavement parts, fertilizer, paints, etc. However, to explore these potentialities it is fundamental to assess the risks that the several forms of use of this residue can cause. For such, in this work the chemical analysis of the residue was performed in order to know its main chemical compounds, in addition to its characteristics of leaching and solubilization. The chemical composition assay showed traces of some heavy metals such as Pb, Cd, Cr, Zn, Al and Cu, although the residue-generating company uses ink labeled as heavy metals free. Among the elements analyzed in leaching and solubilization, some had concentration above the limit allowed by The Brazilian Codes. This code is based on CFR—Title 40—Protection of Environment—Part 260–265—Harzardous waste management. Therefore, it is suggested that the residue has a limited use to avoid contamination of ground water.

Mar 1, 2017

By Zongliang Zhang

Electrowinning is a significant step in metal extraction processes. Because the nature of electrowinning is to reduce metal from its oxidized state, substantial energy consumption accompanies it. Electrowinning processes of different metals have much in common—the deposition of the metal on the cathode and the counter-reaction on the anode. An advanced model was developed that can be applied to a variety of metal electrowinning processes. A model for specific metals can be readily obtained by modifying parameters such as potential, kinetics, and side reactions in the model. The model incorporates mass transfer, gas-liquid flow, electrochemistry, and deposition, making it a comprehensive electrowinning model. The model is applied to copper, nickel, and zinc and verified with the experimental results. In addition, the parameter settings and results of different metals were compared, showing that this model has great versatility and accuracy, thereby making it an efficient and effective research tool.

By Adolf Mikula

Lead-tin solders are commonly used in electronic packaging due to their unique combination of electrical, chemical, physical, thermal and mechanical properties. Since it is known that lead and lead containing alloys cause great environmental concern and health hazards it is necessary to replace lead in solder materials. Besides the environmental concerns new technologies in electronic packaging require new and improved solders. In most cases the new solders will consist of ternary or quarternary alloy systems, the main component will be tin or indium and the second element could be bismuth, silver, copper and gold and to improve certain properties a third element will be added. For a third element zinc, nickel, antimony and aluminum can be considered. This report will concentrate on solders containing zinc as an environmental safe element.

Jan 1, 2003