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By A. Galvan

High rate compressible media filter (CMF) tests produced exceptional total suspended solids (TSS) removal at hydraulic loading rates ranging from 97.8 to 122.2 m/h. The compressible media is manufactured from a robust resin fiber that can withstand low pH and temperatures up to 149 °C. The media porosity can be varied by applying compression onto the media. At 40% compression, the CMF can remove particles greater than 4 μ. Three synthetic test-samples were generated by Hazen Research Inc., (Golden, Colorado) to simulate the copper Pregnant Leach Solution (PLS), Raffinate and Electrolyte solutions used for the testwork conducted at their facility. The preliminary results showed that the CMF was very effective in removing TSS without the use of chemical conditioning from the above test-solutions with efficiencies of 98%, 97%, and 96%, respectively. Given the remarkably high hydraulic loading rates, the industrial equipment footprint would be minimized appreciably over conventional clarification and alternative filtration systems.

By Yuanbo Zhang, Bin Xu, Guanghui Li, Xiao Kang, Chen Liu, Tao Jiang

Iron-bearing dusts, containing valuable constituents such as Fe, CaO, MgO, C, etc., are generally utilized as raw material in iron ore sintering. However, the dusts characterized by low granulating and refractory performances always lead to negative effects on sintering indexes. As we know, the innovative process named composite agglomeration process (CAP) has a series of advantages compared to traditional sintering process (TSP). In CAP, part or all of the iron-bearing dusts is made into green pellets with 5-15mm in diameter, while the rest of iron-bearing dusts and all of the other fine ores is granulated after mixing with fuels, fluxes and return fines. Compared with TSP, CAP could increase the ratio of iron-bearing dusts from 5% to over 20%. Meanwhile, the yield, ISO tumbler index and productivity reached 75.82%, 65.13% and 1.531t·m-2·h -1, respectively.

Jan 1, 2015

By Jiann-Yang Hwang, Ying Qin, Shu-Jing Zhu

Metallurgical Oil Sludge (MOS) is a byproduct created in the process of steelmaking. More than a million tons of MOS are generated each year throughout the world. The material contains hazardous components such as heavy metals and pathogenic organics, which can cause serious environmental problems and health issues. Landfill, combustion, and pyrolysis have been investigated for the disposal of MOS. However, these methods are unsatisfactory since they are unable to reach the clean environment goal. In this study, we investigate the possibility of using MOS as a reductant in a high temperature metallurgical process. The results are reported and discussed.

Jan 1, 2015

By A. René Silva

The separation of Fe(III) from simulated Ni(II) solutions using different ion exchange resins was studied. The resins tested included cation exchangers with sulfonic and carboxylic groups and chelating resins with iminodiacetic, aminophosphonic, and mixed sulfonic and phosphonic groups. The dosage of resins was varied from 0.1 to 0.5 g/mL to study the impact of resin type and dosage on iron separation from simulated nickel leach solution containing 25 g/L Ni(II) and 25 g/L Fe(III) at pH 1.5. Also, the effects of different metal ion concentrations, Fe (III):Ni(II) ratios in solution, pH, and adsorption times were investigated. Experimental results demonstrate that all the chelating resins selected favored the adsorption of Fe(III) over Ni(II) with high Fe(III) loading. Soft cation exchange resins also favored the adsorption of Fe(III) over Ni(II), but no significant Fe(III) loading was observed. In contrast, strong cation exchange resins did not show adsorption preferences. The most efficient separation was observed using resin with aminophosphonic groups at resin dosage of 0.2 g/mL, having a Fe(III) adsorption over 94% and Ni(II) adsorption below 5%.

By Bruno Augusto Batista Ribeiro, Felipe Terra Elias, Wagner Moulin Silva

In the pyrometallurgical production of copper from its sulfides, converting in the Peirce Smith (P-S) Converter is still the most widespread method to obtain white metal and blister copper from the matte. Despite the fact of being a century-old process, it is still possible to achieve improvements in the process, by the use of modern tools, one of the most valuable being numerical calculation and computer-aided simulation. The present study presents three cases in which the angle for the gas injection and the number of working tuyeres are changed during the slag blow phase of the converting process. It was noticed that a decrease of the number of tuyeres, followed by an increase in the injection gas velocity, results in improved reaction volume and less stress to the refractory lining. However, an increase in the amount of copper lost to the slag as oxide is likely to occur.

Jan 1, 2014

By Bora Derin

The partial pressure ratios of sulfur and oxygen for several copper flash smelting plants were derived using the Reddy-Blander (RB) model and predicted dissolved sulfur contents available in the literature. The sulfide capacities (Cs) of six different flash smelting plants (FeO-CuO0.5- CaO-MgO-FeOwAIOl.s?SiO2) slags were calculated. The log (Po2/PS2) versus matte grades of various industrial processes was determined. The PoiPS2 ratio increased with an increase of copper grade. The calculated partial pressure ratios for the copper flash smelting are in good agreement with those of the experimental data.

Jan 1, 2003

By P. Peczak

A Monte Carlo simulation technique has been used to study dynamic recrystallization in polycrystals. A continuum microstructure of the polycrystal is modeled employing a discrete lattice. The response of the material to hot deformation is simulated by adding stored energy and recrystallization nuclei continuously with time. The experimentally observed nonuniform character of deformation substructures is modeled by employing a phenomenological expression for inhomogeneous distribution of the stored energy. All simulations were performed on HP-Apollo 9000 Series 700 workstations. A program written in FORTRAN with use of PHIGS graphics library calls was used to interactively monitor the current state of the matrix and all relevant parameters: deformation stress, average grain size and effective nucleation rate. Visual analysis of the simulated microstructure allows a better understanding of the data developed by averaging over a number of very long Monte Carlo runs. Since the essential features of dynamic recrystallization are accurately reproduced by the model, it is used to discuss the role of the controlling mechanisms of the dynamic recrystallization in real polycrystal.

Jan 1, 1993

By Yasuhiko Ito

"This talk is concentrated on the topics of compound film formation on the substrate electrode by interdiffusion of substrate element and electrochemically deposited species and/or by direct electrochemical implantation of the component element of the film into the substrate. As a typical example, electrochemical implantation of nitrogen atom into Ti metal to form TiN surface film is described. Another example is the formation of various kinds of intermetallic compound films including Ni2Y, Ni2Dy and Pd3 Y by the electrochemical implantation of lanthanoid elements into transition metal electrodes. By combining these two methods, Sm-Fe-N ternary material film also could be formed. The principle and application of the ""electrochemical implantation"" are discussed in detail.IntroductionGenerally speaking, surface film formation by molten salt electrochemical process can be divided into the following three categories:(i) single element film formation on the electrode by electrodeposition,(ii) compound film formation on the electrode by electrocodepostion of more than two elements, and(iii) compound film formation on the substrate electrode by interdiffusion of substrate element and electrochemically deposited species and/or by direct electrochemical implantation of the component element of the film into the substrate.This talk is .concentrated on the topics of category (iii), especially on the electrochemical implantation. Typical example can be seen in the electrochemical implantation of nitrogen atom into Ti metal to form TiN surface film. Another example is the formation of various kinds of intermetallic compound films including Ni2 Y, Ni2Dy and Pd3 Y by the electrochemical implantation of lanthanoid elements into transition metal electrodes. By combining these two methods, Sm-Fe-N ternary material film also could be formed. The principle and application of the ""electrochemical implantation"" are discussed in detail with examples above as well as other experimental results also obtained very recently in the author's laboratory."

Jan 1, 2000

By M. Yoshida, S. Hanada, T. Takasugi

"A study has been conducted to examine the effect of ternary alloying elements on high temperature deformation of the C15 NbCr2 based intermetallics in Nb-Cr-X (X=V, Mo and W) alloy systems, which have attractive properties as high temperature structural materials. The high temperature deformation of the C15 NbCr2 intermetallics can be improved by two alloying methods. One method is based on geometrical consideration for site occupation and atomic size factor of component elements and additive elements in the single phase C15 lattice; addition of Mo and V can promote dislocation movement without introducing significant hardening. The other method is based on microstructural modification through ternary alloying; moderate addition of these elements results in a variety of duplex microstructure consisting of the C15 phase and bee solid solution without forming any intermediate phases, and can enhance the high temperature deformability. Particularly, alloys with duplex microstructure equilibrating with Cr-rich bee solid solution is shown to exhibit superior deform ability. Also, lattice property of the additive atoms in the C15 structure and phase relation between the C15 structure and the bee solid solution are investigated by OM, XRD, TEM and ALCHEMI observations and then discussed in association with observed mechanical behavior.IntroductionLaves intermetallics with AB2 stoichiometry belong to the largest group in a large number of intermetallics with various kind of crystal structures, and have a variation of the cubic CIS, the hexagonal C14 and the dihexagonal C36 structures, depending on stacking sequence of XYZ type, each of which consists of four interpenetrating atomic layers (1-3). Some of the Laves intermetallics have good functional properties and therefore are considered to be used as, for instance, magnetic materials, magneto-optical materials, hydrogen storage materials and superconducting materials (2). Also, the Laves intermetallics are considered to be good candidate as high temperature structural materials operating at high temperatures and in severe environment because they have high melting point, low density, and potential resistance to corrosion and oxidation. However, the Laves intermetallics are very brittle at low temperatures because they consist of complex crystal structures similar to many other intermetallics."

Jan 1, 1996

By Abhishek Lahiri, Animesh Jha

"A new technique for the selective separation of rare earths and impurities from lower grade titaniferous ores has been developed which will reduce the overall reduction in the energy costs, and therefore the CO2 generation by at least an order of magnitude during the chlorination and waste handling stages of TiO2 to TiCl4 reaction. The process includes roasting the ilmenite ore with alkali followed by water washing step, which removes nearly 80% of oxides of lanthanide and actinide elements present in lower grades of titaniferous minerals. In the context of preferential separation of rare- 3+ + earth and actinide oxides, we have examined the roles of Al and K ions on the lattice structures of ilmenite and complex titanate as the product layer forms during the roasting in air in the presence of potash. The composition of the mixtures of oxides derived from the separation process shows that the mixture of rare-earth oxides m ay be a high-value co-product of the overall beneficiation process.IntroductionWorldwide the production of synthetic rutile is carried out either by the sulphate or the slag-making followed by fluidised bed chlorination of TiO2 enriched slag granules. The chlorinated gas is then re-oxidized to make white pigment grade TiO2. The waste generated by the sulphate process is predominantly iron sulphate, which has limited use in the water treatment plant. The remaining wastes from the sulphate process undergo further treatment using filtration followed by evaporation and thermal decomposition after which it is disposed into deep sea. On the other hand the chloride waste is extremely hazardous and requires special case by neutralisation, followed by impoundment in a managed pond, where it is monitored for long-term for potential contamination to the soil and ground water. Rare-earth and prelanthanide wastes often end up in the pond where they are diluted and irretrievably lost for further use or recycle. Certain parts of the world the chloride process wastes are pumped via deep boreholes into porous geological strata. The present techniques of disposal are not only expensive but also pose continued threat groundwater and soil and marine life in case of sulphate waste [1, 2]."

Jan 1, 2009

By D. M. Hausen

It has been demonstrated that microscopic techniques can be applied in a practical manner to the study of spodumene liberation in the processing of pegmatitic ores at the Kings Mountain spodumene plant, Kings Mountain, North Carolina. Spodumene and associated non-opaque gangue minerals are identified and quantified by microscopic point-counting of polished thin sections of heads, concentrates, middlings and tails fractions. Specially prepared polished thin sections? provide uniform thickness of particles for measurement of diagnostic optical properties and the alternate use of incident and transmitted light in distinguishing the various gangue and ore minerals. Spodumene is commonly associated and interlocked with quartz, albite, microcline and muscovite. Concentrate grade depends on the degree of spodumene liberation, which in turn depends on the crystal size and textural association of interlocked minerals. The liberation of spodumene can be measured as a function of screen size by means of microscopic point-count data. Microscopic data also provide useful metallurgical information about the nature of diluent minerals in spodumene concentrates, and the form of lithia losses in the tails. Lithium assays correlate closely with microscopic spodumene analyses in various flotation products from Foote Mineral's Kings Mountain plant, and confirm the applicability of quantitative optical microscopy to the study of liberation and recovery of spodumene from pegmatitic ores. A better understanding of recovery-grade relationships was developed as a result of quantitative microscopy studies.

Jan 1, 1981

By A. D. Zunkel

Increasing amounts of electric arc furnace dust (EAFD) are being generated worldwide as more steel is produced from electric furnace melting of galvanized steel scrap. In most countries, the management of this material is a costly technical, economic, and legal problem for minimill steelmakers. Many technologies and processes are being developed and implemented worldwide to manage this material to recover contained zinc, lead, and iron values and render it nonhazardous. These processes are pyrometallurgical, hydrometallurgical, or hybrid in nature. Some produce zinc oxide, some zinc metal, some lead metal, and some lead cement. Some are successful, some have failed, many are dormant. or abandoned, and others continue to be developed and emerge. This paper updates the current status of 20-30 processes in various stages of commercial application and development used worldwide to manage EAFD and recover its nonferrous, particularly zinc and lead, and ferrous values.

Jan 1, 2000

By Xie Hao

According to its raw materials orthogonal test scheme is designed and a large number of systemic experiments were carried out in order to study the sintering characteristics of three types of fine ores in Kunming Iron&Steel Co.Ltd(KISC). The effects of carbon mixture ratio and basicity on sintering time, agglomeration ratio, physical properties and utilize coefficient were researched via single factor analysis and range analysis. The experimental results show the best mixture ratio of each fine ore. Analysis found that the influence of the carbon mixture ratio is more significant than which of the basicity on the sintering process except agglomeration ratio of foreign ore.

Jan 1, 2009

By Luciano B. Oliveira, Alexandre M. Stumbo, Luis G. C. Marques, Valdo S. Marques, Sergio N. Monteiro

"Similar to the ethanol program, initiated more than 30 years ago, the recently created biodiesel program in Brazil is expected to rely on private initiative based on agribusiness for vegetable oil production. Campos dos Goytacazes is a large county in the northern of the state of Rio de Janeiro with land still available for oily vegetables plantation in addition to the land traditionally occupied by sugar cane plantation, which is used to produce ethanol. In order to extend the biodiesel program to Campos dos Goytacazes, the State University of Northern Rio de Janeiro (UENF) is conducting a technical project for the development of the infrastructure for biodiesel production. In this work, the infrastructure based on versatile equipment for biodiesel esterification built in the Center for Alternative Energy of the UENF is presented.IntroductionBiofuels are gaining worldwide attention as a possible economical solution for the prediction of declining reserves of petroleum and related increase in price of barrel. However, nowadays, a more relevant question is the climate changes caused by burning fossil fuels. This is especially the case of coal and petroleum based fuels, mainly gasoline and diesel that propel the majority of vehicles and generate a large amount of CO2 emissions responsible for global warming. This combination of economical an environmental problems is already providing a strong motivation to substitute conventional fossil fuels by renewable biofuels. More than just the interest of the market financial forces, government legislation is imposing a new order that obliges the use of biofuel. Many countries including the USA, the European Community, Japan and Brazil are committed to gradually substitute biofuels into their fleet of vehicles."

Jan 1, 2008

By A. Mezei

A process has been developed to recover cobalt, gold and bismuth from the NICO deposit in Canada. The process consists of a bulk rougher flotation followed by an optional separation by flotation to produce a bismuth concentrate and a cobalt concentrate, grading on average 12.8 % Bi and 1.8% Co, respectively. Cobalt is leached by pressure oxidation at 97% efficiency, producing a pregnant solution suitable for further processing. Before optimization, about 38% of the bismuth is recovered in the selective concentrate, wherefrom it is recovered by ferric chloride leaching followed by cementation, at overall efficiencies exceeding 98%. The gold is recovered from the cobalt and bismuth leach residues by cyanidation, at 95% efficiency. Previous work described the results of the leaching of the concentrates, recovery of gold (Part I) and the recovery of bismuth (Part 11). This work describes the results of the cobalt recovery testwork and the resulting conceptual flowsheet. The sulfur dioxide-oxygen system was the most efficient for the oxidationlprecipitation of iron and arsenic from cobalt bearing pregnant leach solutions, producing purified solutions assaying <1 mg/L As and <8 mg/L Fe. The efficiency of cobalt solvent extraction (from the resulting purified PLS containing about 1 g/L Co) ranged from 9 1 to 98%; the co-extractions ranged from 88 to 100% for copper, from 28 to 33% for magnesium, from 6 to 7% for calcium and from 96 to 98% for zinc. Sulphide precipitation processes (using either sulfur dioxidelelemental sulfur or sodium sulfide) produced residual copper concentrations in the cobalt strip solution ranging from 0.1 to 2 mg/L Cu. About 90% of the calcium and magnesium were separated by scrubbing the organic with cobalt sulfate, producing residual concentrations of 12 mg/L Ca and from 180 to 330 mg/L Mg in typical feed solutions directed to cobalt carbonate precipitation tests. Cobalt carbonate precipitation efficiencies ranged from 75 to 78% when calcium and magnesium co- precipitations were restricted from 8 to 17% and 0.3 to 0.4%, respectively. The limits required by most stringent specifications on commercial grade cobalt carbonate products were met or exceeded.

Jan 1, 2002

By Paykan Safe

Computational Fluid Dynamic (CFD) modeling provides a powerful tool to assist with the design of ventilation and fume control systems in smelters and other high temperature metallurgical facilities. For this paper, this tool has been used to analyze the off-gas flow patterns exiting the mouth of a Peirce-Smith converter into a water-cooled hood and drop out box. The effects of various process and physical plant design parameters on process gas and fume capture and potential build up on the converter hoods was examined, and the optimum design and operating parameters were determined.

Jan 1, 2000

By Bin Xu, Qian Li, Yong-bin Yang, Xiao-liang Liu, Tao Jiang, Yan Zhang

Some high sulfur and arsenic-bearing gold concentrate has a gold leaching rate less than 80% by oxidation roasting-pickling-cyanidation process. The characteristics and intensification of gold leaching were studied systemically. By combining chemical composition and phase analysis, the low gold leaching rate was found to lie in the capsulation of gold by iron-containing phases including iron oxides, arsenopyrite and pyrite. 96.66% of gold in the industrial leaching residue was capsulated and 95.88% of the capsulated turned out to be in the iron-containing phases. The results of laboratory pickling-cyanidation experiments on the calcine and industrial leaching residue presented further demonstration for the fact that gold capsulated in the iron-containing phases was hard to be leached. However, the gold cyanide leaching rate of calcine could be raised over 95% by a reduction roasting-pickling pretreatment which played such a significant role in exposing the capsulated gold that gold leaching was intensified remarkably.

Jan 1, 2015

By S. Kang, D. G. C. Robertson

Slag cleaning furnaces require extensive wall cooling because they involve the use of a superheated slag bath. This is in direct contrast to smelting furnaces, where the wall is usually (but not always) protected by "banks" of solid charge. In order to understand the heat transfer and flow in slag cleaning furnaces a number of model studies have been carried out using molten wax to simulate the slag. Wax is a good model fluid because, like slag, it has a high Prandtl number. Wax models cannot simulate the behavior close to the electrodes (DC arc or AC submerged), but they can and do give a good simulation of the flow and heat transfer at the wall. An understanding of these phenomena is of great importance for the design of cooling panels in the walls of the furnace. Since superheated molten slag will eventually wear away any refractory bricks over time, the wall cooling must be designed to form a frozen layer of slag, referred to as a "freeze lining". The heat flux density (Q/A) required to do this is given by Q/A = h* ?T, where h is the heat transfer coefficient in the slag phase at the wall, and Li T is the superheat (bulk slag temperature - liquidus temperature). Both Q/A and h vary greatly with position and both are usually a maximum at the slag line. In the experimental work, molten wax baths were heated by block heaters to provide similar energy densities to those encountered in commercial slag cleaning furnaces. This procedure was considered to be valid since most of the electrical energy into a furnace bath is dissipated as heat. Gas stirring was used to simulate the gas evolved at the electrode in real furnaces - the quantity of this gas could be estimated from a knowledge of electrode consumption. The similarity criterion was equal gas flow per unit area of surface, in model and prototype. Heat transfer coefficients were measured in the models as a function of power density, gas stirring, superheat, etc., and could be related to the full-scale operations by the use of dimensional analysis.

Jan 1, 1999

By Adam Powell

A Cahn-Hilliard phase field model is formulated to describe transport-limited electrochemical reactions coupled with fluid flow in a metal reduction cell. When the reaction is limited by mass transfer of metal ions from the electrolyte to the cathode, the metal-electrolyte interface at the cathode exhibits a Mullins-Sekerka instability, leading to the growth of dendrite-like "streamers" of liquid metal into the electrolyte, which in turn significantly enhance the apparent mass transfer coefficient there. Model results for iron reduction from ferrous oxide in slag show formation of these streamers. Although the double-layer is not included in this model, the related phenomenon of electrocapillarity can be represented by a gradient penalty term which includes the electric potential gradient, such that interfacial energy is a function of the electric field normal to the interface.

Jan 1, 2003

By Robert Matusewicz

Ausmelt Technology has been applied to the recycling of spent pot liner (SPL) generated from primary alnminum production. The process is centered on the Ausmelt furnace, in which the SPL is converted under high temperature, oxidizing conditions to an HF containing gas stream and inert slag. fluorine is recovered from the SPL as HF gas and is concentrated and used to manufacture AIF) for recycle to the aluminum smelters. Approximately 87% of the fluorine can be recovered and converted to AIF), with the remainder being effectively tied up in the by product slag. Cost projections show that the recycling process will be competitive with other processes for SPL. The production and recycling of AIF) provides available credit that significantly offsets the operating cost of the facility. Ausmelt Technology for recycling of SPL is currently being marketed in North America by Ausmelt Technology Corporation in Denver, Colorado, and in the rest of the world by Ausmelt Limited of Dandenong, Australia.

Jan 1, 1996