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By W. Petruk

The silver-rich cobalt-nickel arsenides ores of the Cobalt area in Ontario, Canada were mined for silver from about 1904 to 1985. The ores contained about 8 oz to 100 oz Aglt and about 1 wt% Ni and 2 wt% Co. They were processed by gravitational techniques, screening and flotation to produce separate silver and Fe-Co-Ni arsenide concentrates. The silver concentrate was smelted, and in some cases the arsenide concentrate was sold to custom smelters which recovered silver and other metals. The ores display a wide variety of textures and contain many minor and trace elements. This paper presents an evaluation of mineral characteristics that have a bearing on extractive metallurgy and smelting of this type of ore.

Jan 1, 1993

By Dirk Verhulst

The Altair Hydrochloride Pigment Process is a new ?third route?, besides the established high-temperature chloride process and the older sulfate process, to manufacture TiO2 pigment from ilmenite ore. It has been tested at a scale of 5 t/day feed. The ore concentrate is digested in high-acid, high total chloride solution (+/- 39% Cl). Titanium and iron both go into solution. Iron is separated as FeCl2 crystals after reduction and cooling. Titanium is transferred by solvent extraction into a purified, high-Ti stream. It is spray-hydrolyzed to produce a TiO2 hydrate and further calcined with additives into high-quality pigment. HCl solutions generated by pyrohydrolysis and spray hydrolysis are treated by pressure-swing distillation to regenerate HCl gas for re-injection into the digestion reactor. All chloride streams are recycled. Recent work has concentrated on optimization, particularly in 3 areas: - Solvent extraction: a new organic mixture, including a new diluent, makes it possible to work at room temperature, to avoid TiO2 hydrolysis problems and to improve phase disengagement and impurity separation. - Pigment finishing: a systematic study of the parameters involved, followed by long runs in the best conditions confirm pigment quality. - Flow sheet optimization: innovative modifications of the conditions of spray hydrolysis and pyrohydrolysis, combined with re-routing of streams achieve significant energy savings. A 100 t/year pilot plant including these features as well as other process improvements is under construction.

Jan 1, 2006

By Ch. -A. Gandin, M. Rappaz

"The grain selection mechanism which occurs during the growth of columnar dendritic structures is routinely used in the investment casting industry to produce directionally solidified (DS) and single crystal turbine blades. However, the evolution of the grain density with increasing distance from the chill has rarely been correlated with the evolution of the grain texture. This contribution presents a three-dimensional (3-D) stochastic modeling approach which permits the computation of grain maps, pole figures and grain density evolutions in DS superalloys. These predictions are compared with measurements resulting from an automatic indexing technique of Electron Back-Scattered diffraction Patterns. This 3-D stochastic model, which applies to uniform temperature situations, has to be extended to the dendritic growth in a thermal gradient. As a preliminary step, a 2-D Cellular Automaton (CA) has been coupled recently to Finite Element (FE) heat flow computations in order to predict the grain structures in complex shape investment cast part. The application of this CAFE model to the investment casting of a turbine blade is presented. Considering these results, the extension of the CAFE algorithm to three dimensions is discussed.INTRODUCTIONThe selection of columnar grains during the directional solidification of alloys plays a key role during the investment casting of directionally solidified (DS) and single crystal (SC) components for aerospace applications [I]. This selection mechanism, leading to a competition of the dendritic network propagation at grain boundaries, has been the subject of many investigations. In particular, the study of Walton and Chalmers [2] is remarkable since it provides a link between the evolutions of the density and of the texture of columnar grains with increasing distance from the mold wall. Since this original work of Walton and Chalmers, two new tools have become available, which enable one to revisit the problem of grain selection in much greater depth. The first one is a fully automatic indexing technique of Electron Back-Scattered diffraction Patterns (EBSPs) [3-6] which directly gives the crystallographic orientation of the solid at any location of the specimen. Pole figures, orientation distributions, misorientations between grains can be visualized very easily with this technique. This information can be directly compared with the results of a second tool: a three-dimensional (3-D) stochastic model (SM) describing the nucleation and growth of grains in a uniform temperature field [6-9]. In order to extend this model to non-uniform temperature situations, a preliminary 2-D model has been developed [10]. It is based on a Cellular Automaton (CA) algorithm coupled with Finite Element (FE) heat flow computations. Since the details of both the automatic indexing technique of EBSPs and the simulation tools have already been published [3-10], only a brief summary is given here."

Jan 1, 1994

By Florian Kongoli

The production of a homogeneous self-fluxing sinter is an important step in iron making processes. A good sinter should have good permeability and reducibility and has to keep those characteristics for a certain time. An early melt down of the sinter in the blast furnace, where its solid state reduction is essential, would cause many problems such as low permeability and reductibility. Nevertheless, the important factors that influence these characteristics, such as the chemistry of the sinter and the fluxing effect during sintering and sinter reduction conditions have not yet been clarified. In today's new reality where many new minor components such as Al2O3 and MgO enter to the sinter through raw materials, the quantification of the fluxing effects during sintering becomes even more important. In this work, the liquidus surface and phase relations of the sinter primary melts in the CaO-FeO-Fe203-Si02 system at sintering conditions have been quantified. The fluxing effect of oxygen potential, Al2O3 and MgO has also been quantified by the means of some practical diagrams that can directly help the optimization of the sintering processes.

Jan 1, 2003

By Jin Liu

In the early 1990?s, Inco successfully installed two new flash furnaces as part of their SO2abatement project to reduce SO2 emissions from the Copper Cliff Smelter by 60%. The flash furnace off-gas is cooled and cleaned through two new Monsanto Dynawave gas cleaning systems that replaced the traditional venturi scrubbing system. It was discovered that the flash furnace production capacity is often limited by the capacity of the gas cleaning system. The key task is to eliminate pressure drop from the system. The froth column is responsible for by far the largest pressure drop in the gas cleaning system. Initially, the column was fitted with 22 plates. In 1994, both #1 and #2 froth columns were modified by reducing the number of plates in each column from 22 to 18 and increasing the interplate spacing on lower plates. With increasing demand for more throughput in the flash furnaces, further modifications on the froth columns were made in 2005. This paper describes these modifications and results together with some fundamental analysis of the froth column characteristics.

Jan 1, 2006

By E. A. Thiers

The causes of structural changes in the markets for high technology alloying metals are discussed in terms of technological, economic, and financial trends. Recent market imbalances have affected producers in developed and developing countries differently. Possible response strategies for suppliers in the two types of countries are examined that may alleviate future market imbalances.

Jan 1, 1988

By Osarnu Inoue

In Mitsubishi Continuous Copper Smelting and Converting Process, smelting, slag-matte separation and matte converting are continuously carried out in series in three furnaces connected by launders. As a result of this operational configuration of the furnaces, influence of the change in operating condition in upper stream, such as variation of feeds in the smelting furnace, propagates to down stream with some delay. In order to achieve stabler operation, process control algorithm based on the dynamic characteristics of each furnace would be very effective. In this study, the dynamic process simulation model was developed for the smelting furnace. The model consists of two mathematical modules, i.e. the thermodynamic module and the mixing module. The calculation results using operating data obtained at Naoshima Smelter showed good agreement with the actually observed change in temperature, composition and flow rate of matte and slag at the outlet of the furnace. In addition, operation parameters such as reaction efficiency of oxygen and coal, dead volume of melts were estimated.

Jan 1, 1999

By S. M. Copley, M. Yankova, E. Y. Yankov, J. A. Todd

"Nanophased coupled growth structures, with spacings of -10 nm, have been observed in banded microstructures produced by laser melting hypoeutectic Ag-Cu alloys. These coupled growth structures comprised a Cu-rich phase of width - 1 nm and a Ag-rich phase of width - 9 nm. In this paper, microstructural observations of nanophased coupled growth structures in hypo eutectic AgCu alloys are presented. Laser beam velocities for the transition from banded to microsegregation free microstructures are modelled and compared with experimental values. Models are presented to show that, at a critical undercooling, initial growth of a Ag-rich, metastable, extended solid solution is rapid but slows to a halt as copper is partitioned into the liquid at the solid/liquid interface. Following nucleation, the coupled growth structure then grows until the partitioned copper is consumed, at which point growth of the Ag-rich solid solution is again accelerated. This cycle then repeats resulting in banded microstructures comprised of 750 nm of the Ag-rich extended, metastable solid solution, followed by 250 nm of the coupled growth structure.1. Structural Studies of Laser Melted and Resolidified TrailsPresented here are observations of laser melted and resolidified trails in Ag-Cu alloys obtained at beam velocities ranging from 0.7 to 34 cm S·I. When the laser beam is scanned along the surface (positive x-direction) with a velocity Vb a melt pool with the shape given in Fig. 1a moves with the beam. The isotherms move with the velocity, Vi,. = Vb cos.p. Calculations employing the thermal analysis of Kou, Hsu and Mehrabian [1] for the beam velocities of this investigation and for the thermal properties of AgCu alloys, indicated that, .p, the angle between the isotherm velocity and beam velocity should be small at the surface where microstructural studies were made. This prediction was supported by observations of trail cross-sections. Based on these observations, and the calculations which include latent heat effects, the isotherm velocity for observations near the surface in our investigation was taken to be 27 cm S-I."

Jan 1, 1994

By Carla Lupi

In this work, nickel-cobalt electrodeposition under galvanostatic conditions was investigated. Ni-Co alloy was electrowon from an acid sulphate bath containing 40 g/L Ni and2-8 g/L Co.. The effect of electrolyte composition, current density, temperature, solution pH and presence of buffers such as H3BO3 and (NH4)2SO4 on Co content of the binary alloy has been investigated. In particular, current densities ranging from 180 to 400 A/m2 and temperatures ranging from 27 to 60°C were tested. The composition of Ni-Co alloys may be diversified through the selection of process parameters. The experiments show that the highest cobalt content of the alloy is reached by using a buffer free electrolyte without solution pH control. Though, in these conditions, the most homogeneous, fine and regular deposit morphology is obtained, energy requirements are the highest in tests lasting just two hours.

Jan 1, 2003

By Peter Fischer

A demonstration plant for QSL technology with a continuous through-put of up to 10 t/h concentrate has been in operation at the Berzelius smelter, Duisburg, Germany since early 1981. In the QSL-process, both oxidation and reduction steps are performed in a single horizontal long cylindrical reactor. In the present demo-reacior, 2.5 M diameter by 22 M long, these steps are separated by a low partition wall with an underflow opening, to prevent backmixing of slag. -Tests on a variety of concentrates, including high-lead Missouri-type material and lower grades, have shown recoveries and consumables indicating very attractive economics. Investment cost estimates further enhance the economic attractiveness. Environmental protection afforded by the QSL system is a major advantage. The process has proven its reliability and versatility and is now ready for commercialization. Continued test work, including smelting secondary lead materials, is planned.

Jan 1, 1983

By Chen L. Lin

Scientific visualization is an ideal methodology for investigating complex phenomena that are characterized by large amounts of data. Furthermore, it is invaluable in the study of processes that evolve in time. Scientific visualization relies heavily on computer graphics, image processing and video technologies. Specific applications of scientific visualization in the minerals and materials processing fields that are considered in this paper include: 1) applied CT technology for multiphase materials and minerals, 2) time averaged density profla in air- sparged hydrocyclone (ASH) flotation and 3) dynamic motion analysis of ball mill grinding.

Jan 1, 1993

By M. Olper

Today, copper production from direct leaching of oxidized copper ores followed by solvent extraction-electrowinning (SX-EW) accounts for about 15% of the total primary world output. SX-EW is a well-accepted process with an operating cost in the range 16-20 cents/lb. copper for small and medium size plants, depending on the plant size and local conditions. However, this technology presents some drawbacks that affect the operating cost and cause environmental concerns. ENGITEC and Paques Bio Systems have developed a new process that avoids the solvent extraction step and operates the copper electrowinning step at a lower cell voltage because of the depassivation of the anodic reaction. The consequence of this new concept is that the direct operating cost is in the range 10-12 cents/lb. copper. This new process is composed of the following steps: ? Selective precipitation of copper from leach solutions by biogenic H2S, yielding CuS and regenerating acid ? Leaching of the CuS with a ferric fluoborate solution to dissolve copper and produce elemental sulphur that is recycled back to the H2S biogeneration step ? Electrowinning of copper fluoborate solution in a diaphragm cell with the ECUPREX® Process, producing copper cathodes and regenerating the ferric fluoborate solution to be recycled back to the leaching step ? Biogeneration of H2S from the elemental: sulphur generated during the leaching step, with the nutrient source for the anaerobic bacteria selected form a wide range of organic substances and/or some industrial by-products containing carbon and hydrogen This paper describes all process steps with particular reference to the biological H2S generation technology. Also discussed' is the capability of the ECUPREX® Process to treat copper sulphide concentrates and copper matte.

Jan 1, 1999

By Tatiana Pereira Moreno, Priscilla Aki Mori de Hanashiro, Viviane Tavares de Moraes, Denise Crocce Romano Espinosa, Hugo Hashimoto

"Nowadays, End-of-Life (EoL) Liquid Crystal Displays (LCDs) are traditionally disposed in landfills. The increasing access to LCD technology over the last years by Brazilian consumers has intensified LCD' s disposal as an environmental and economic issue. This study aims to characterize used LCDs to identify the main components for recycling. Characterization was performed through scrap disassembly and its components were identified, separated, and weighted. LCDs were disassembled and the following divisions were applied: screen, metal frame, polymeric frame, polymeric sheets and electronic part. Some techniques were used to determine the concentration of Indium in the LCD, the glass/plastic ratio and the different kinds of polymers that compose the screen. The techniques used for characterization included inductively coupled plasma optical emission spectrometry (ICP-OES), Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA). This method, when applied to a wide range of LCDs, can allow the development or improvement of an EoL management of LCD.IntroductionWaste Electrical Electronic Equipments (WEEEs) are waste from discarded equipment, such as computers, monitors and cellphones [1]. Over the past years, treatment of WEEE has been emphasized. It occurs due to the technology's advancement that leads to an even larger increase of WEEES [2].Among WEEEs, there are the liquid crystal displays (LCD). LCD technology is applied in cell phones, tablets, computers and monitors. Nowadays, it's the most well known technology when it refers to monitors, due to its advantages over the Cathode Ray Tube (CRT) technology. Some of them are energy saving, smaller size and no radiation emission [3].This feature in the LCD's global market along with the speed at which electronic equipment becomes obsolete affects society economically and ambiently.This issue becomes even more serious when considering the final destination of the liquid crystal displays. LCDs are lead to landfills as other WEEEs. Besides the different materials long degradation time, the environment is damaged by the disposal of the potentially reusable and hazardous materials [ 4]."

Jan 1, 2014

By C. A. Landolt

Inco pioneered the use of tonnage oxygen in non ferrous metallurgy when it commissioned the first industrial oxygen f1ash smelting process for the treatment of copper concentrates in the ear 1y fifties. This techno logica1 innovation was followed by other applications of technical oxygen. Inco is currently implementjng a Sulfur Dioxide Abatement Program designed to reduce SO2 emissions from the smelter by 60% in 1994. The new flowsheet includes new equipment for the oxygen flash smelting of Cu-Ni concentrates and for flash conversion of chalcocite. Oxygen smelting and converting technology will lead to a substantial decrease in use of fossil fuels and to generation of high strength S02 off gases suitable for efficient fixation in a new acid plant.

Jan 1, 1992

By R. Cameron

The growing use and acceptance of electric vehicles (EV), as evidenced by the record sales of over 750 thousand vehicles in 2016 and a current global EV stock of 2 million vehicles, is putting pressure on sourcing raw materials such as cobalt, and to a lesser extent, nickel. Global supply is poorly diversified, with 50– 60% of global cobalt production sourced solely from the Democratic Republic of Congo (DRC). One potential source for cobalt and nickel are low-grade nickeliferous pyrrhotite tailings, of which 50–100 million tonnes are present in the Sudbury area alone. This paper presents the extraction of cobalt and nickel from this material using a combination of flotation and bioleaching technologies. The findings of a high-level techno-economic analysis of the proposed processing flowsheet are presented.

By J. Garvey

The new Cyprus Miami electrolytic copper refinery was commissioned in October 1994. The refinery has been operating at its design capacity of 190,000 short tons per year, and in recent months to 110% of design capacity, producing high-grade electrolytic copper cathodes. Basic and detailed engineering, performed by Fluor Daniel Mining and Minerals, incorporated state-of-the-art technology, including stainless steel cathodes, automated electrode handling, fine-filtering of the commercial electrolyte, autoclave leaching of the anode slimes and other techniques. The major design goals have been safety of operation and quality of the product. Relatively high cathode current densities of 30 amperes per square foot and greater have been applied since start-up. Cathode current efficiencies of over 94% have been achieved since the latter part of 1997. The cathodes were certified on the Comex and LME markets during 1996. ISO- 9002 certification is in progress and should be completed during the first quarter of next year. This report discusses some of the studies that were performed to obtain an optimum layout for efficient materials handling and to create optimum conditions for producing high quality cathodes. A description of the design and operation of the anode slimes facility, including decopperizing with autoclave leaching, is provided. Finally, a description of the start-up experiences and present operation of the electrorefinery are presented.

Jan 1, 1999

By Tracie Zoeller, G. Paul Neitzel, Jr. Sanders

"As-cast aluminum alloy microstructures are highly segregated. Coring occurs when solute is rejected during solidification resulting in a non-uniform solute distribution across the dendrite arms. Furthermore, coarse constituent phases are formed in the interdendritic channels as a result of coring. These constituents are either soluble or insoluble and can form from the major solute elements, or the impurity elements iron and silicon. The dissolution of these constituents, or precipitates, is an important consideration in determining the microstructural evolution of an alloy. The properties of an alloy are significantly affected by the morphology of the precipitates. Precipitates can be either beneficial or detrimental to the properties of the alloy. Regardless of the nature of the precipitates present, it is useful to understand the dissolution process. A diffusion-limited dissolution model for planar precipitates is presented and compared to an analytical solution and to models in the literature. Experimental data for the dissolution of AhCu precipitates in a dilute alloy are compared to the proposed model, and found to have good agreement.IntroductionDuring the processing of precipitation hardening alloys, beginning with the solidification step and ending with the final solution heat treatment step, there are a variety of particles that form. Some of these particles must be dissolved and solute redistributed and re-precipitated in a more homogeneous distribution than as it first appears in the as-cast microstructure. The particles can be classified by size as microstructure develops during processing. Coarse particles that form during solidification can either be soluble, partially soluble or insoluble. These particles can be the result of coring of the major solute elements as well as the limited solubility of elements such as iron and silicon. Iron and silicon can combine with the major solute elements such as copper in 2xxx alloys forming coarse phases often referred to as constituents. Figure l(a) shows the as cast microstructure with the constituent phases, Al2Cu and the insoluble phases containing Al-Fe-Mn-Cu-Si [7]. During preheating the soluble phases such as AhCu that were formed by eutectic decomposition must be taken back into solution, whereas the insoluble phases remain essentially unchanged by most thermal operations. Figure l(b) and (c) show some of these constituents after subsequent preheating steps. In Figure l(b), AhCu platelets are shown and in Figure l(c) the remnants of the AhCu phase are noticeable, along with Mn-bearing dispersoid phases. Reduction in the volume fraction and size of these phases improves the ductility and fracture toughness as well as reducing the inhomogeneities that occur during coring. Also adjacent to the dendrite arm boundaries are smaller AhCu phases that precipitate by a solid-state transformation on cooling to room temperature."

Jan 1, 2004

By T. S. Montgomery

The performance of carbon-magnesia brick in electric arc furnaces (EAF) is interpreted in light of their observed optical microstructures. Features at the bricks' hot faces were protruding periclase grains, metal globules, graphite-metal contacts and linear void patterns. These features were com-pared to similar features previously seen from microstructures of basic oxygen furnace (BOF) refractories. Modes of formation were sought; an attempt was made to interpret their influence related to wear mechanisms.

Jan 1, 1982

By Zhang Libo, Wang Xin, Peng Jin-hui, Ju Shaohua, Guo Sheng-hui, Xu Lei, Huang Meng-yang

"China is lacking high grade titanium ores. This work intends to leach impurities such as Fe, Ca and Mg from a low grade titanium ore, to increase the grade. The original material contained 65% TiO2 , 16.12% Fe, 9.4% CaO + MgO, 4.2% SiO2, 1.25% A12O3, and the particle size is between 0.053-0.045mm. Microwave energy was used to enhance the leaching effect. The results showed that when normal heating was used to leach the mineral, the extraction of impurities Fe, Ca and Mg was very low. However, when microwave energy is introduced, the extraction of Fe, Ca and Mg increased dramatically. The optimized conditions are: relative power 5W/g, the ratio of concentrate to HC1 isl5%, leaching at 160°C for 20 min with a ratio of liquid to solid 12:1 mL/g. The material obtained under these conditions contains 92.73% TiO2, 0.207% Ca + Mg, 0.8% Fe, with 94.6% Ti recovery. The poduct meets with the quality for boiling chlorine.IntroductionThe resources of titanium are very abundant, and are distributed all over the world. There are almost 140 minerals containing TiO2 with a content of more than 1%. However, there are only several minerals which can be used for producing sponge titanium. They are mainly rutile and ilmenite. The grade of nature rutile concentrates is higher than 95% TiO2, and it is a high quality raw material. But the resources of nature rutile are relatively low; after mining for many years, its resources are exhausting gradually. Although ilmenite reserves are great, ilmenite cannot be used as a raw material because of its low content of TiO2, only 45-70%; also it has a high impurity content of Ca, Mg and Fe. In these years, there is a tendency for titanium industry to use high grade concentrate."

Jan 1, 2012

By N. L. Piret, E. N. Mounsey

Ausmelt technology is successfully used to process primary and secondary materials to produce lead in large-scale commercial operations and to meet stringent environmental standards. The development and commercial data covering these applications and the results with respect to metallurgical, cost and environmental performance are reviewed in commercial operations. A new smelter is scheduled for commissioning in 2000 at Korea Zinc's Onsan site to process lead fume and other secondary materials to produce 50,000 tonnes per annum of lead bullion. The unique features of Ausmelt technology also allow for the efficient processing of polymetallic concentrates and secondary materials, particularly copper and lead, through the effective separation of these elements into metal, slag and fume species. This capability has been successfully demonstrated at a commercial scale and the results and implications for the industry are discussed.

Jan 1, 2000