Search Documents

By S. Shairp

Copper is an impurity as well as a necessary reagent in the processing of zinc sulfide concentrate at Hudson Bay Mining & Smelting Co., Limited's (HBMS) zinc pressure leach plant. Copper is present in the zinc concentrate as chalcopyrite, which consumes reagents necessary for zinc leaching. A small percentage of copper precipitates in the autoclaves, discharge lines, and flash tanks, requiring maintenance of the equipment and disposal of the solids. Copper also precipitates in the neutralization stages and is removed to low levels in a specific copper removal stage of purification. Yet some copper, as copper sulfate, is required, along with potassium antimony tartrate, in the final purification stage to improve cobalt removal from the zinc sulfate solution prior to electrowinning. The behaviour of copper experienced at HBMS's zinc pressure leach plant is discussed.

Jan 1, 2008

By J. Gao

We present results from our investigation of the concept and practice of using surface-charged latex nanoparticles as building blocks for conductive membranes. Nanoparticles were synthesized by free-radical co-polymerization of two hydrophobic monomers, butyl acrylate (BA) and methyl methacrylate (MMA), a crosslinker, N, N'- methylenebisacrylamide (BIS), and a charged monomer, sulfonate styrene sodium salt (NaSS), in water. The resultant nanospheres were characterized with static and dynamic laser light scattering. Thin films were cast from concentrated particle dispersions, followed by incubation at ?110 °C. Conductivity, water uptake and final charge content were measured. The membranes have higher conductivities than both amorphous films cast from sulfonated BA-MMA-Styrene copolymer chains and BA-BIS-MMA-NaSS gel films. TEM images and neutron scattering spectra confirm the particulate structure of the membranes.

Jan 1, 2005

By S. D. Logan

This presentation describes a lightweight automobile body structure concept developed at DaimlerChrysler to support a high fuel-efficiency vehicle project. This body structure consisted primarily of large thin-wall magnesium castings and resulted in a more than 40% weight reduction with a minimal cost increase over a conventional steel structure while achieving significantly improved structural performance as evaluated through CAE simulations. One concept vehicle was built for the purpose of demonstrating concept feasibility. Several slides showing the prototype build process are presented. The presentation also describes several large thin-wall die casting body applications that are in current production or have been used in recent production automotive applications and identifies areas where further development could improve the chances of a magnesium intensive body structure becoming a production reality at a later time.

Jan 1, 2006

By R. Ham-Su, J. P. Healey, S. P. Farrell, R. S. Underhill, M. A. Gharghouri, C. V. Hyatt, L. M. Cheng

Magnetic shape memory alloys (MSMA's) are a class of materials where magnetic energy can be converted into mechanical energy and vice versa. NiMnGa-based MSMA's have attained magnetic field induced strains up to approximately 10% and have a relatively wide operating temperature range, from well below 0°C to above RT, making them very attractive for a variety of applications. However, these materials also suffer from low toughness. Using these materials in a composite could mitigate this shortcoming, and also overcome limits imposed by inertia and eddy current losses. In this work, we describe the manufacture and characterization of such composites. Composites with 30% by volume MSMA were fabricated under a magnetic field resulting in anisotropic magnetic properties. Damping properties were evaluated by dynamic mechanical analysis.

Jan 1, 2004

By S. Orzecki

The KGHM Copper Refinery Plant, Glogów 1, has operated for 35 years and -increased its capacity almost ten times.Cathode quality, expressed in terms of the total impurity content, has undergone a five-fold improvement. The present refining capacity is equivalent to 240,000 metric tonnes of copper cathode, with a total impurity content of 20 ppm, inclusive of 10 ppm Ag. These accomplishments result from combined implementation of current technological progress in electrolytic refining and KGHM's own solutions applied to the Glogów Refinery. The quality improvement measures feature both lowering actual current density, despite an increase in nominal current density, and diminishing the role of non-ion mechanisms which transfer impurities to cathodes. The paper contains a detailed discussion of these issues and outlines possible measures aimed at further production and quality improvements.

Jan 1, 2007

By M. Özer, F. Boylu, G. Önal

In this study, the fine coal waste subjected to the experiments is taken from the waste stockpile of Soma Coal Plant. The possibilities of its evaluation and the production of clean coal were investigated. For this purpose, Reichert Coal Spiral and Shaking Table are used. The minus 1 mm coal waste includes 60.43% ash and 50% minus 38 micron material by weight. The microscopic observations of the screen fractions were shown that the clay minerals are in fine sizes and the coarser size fractions contain silica and carbonate minerals as ash forming materials. The tests were conducted after desliming. The commercial grade clean coal product containing 29-35% ash with a calorific value of 3800-4200 kcal/kg (15.91-17.58 MJ/kg) was obtained by gravity methods.

Jan 1, 2004

By W. T. Thompson, S. Durham, K. M. Jaansalu

The role of platinum on the relative stability of gamma - gamma prime equilibrium is only qualitatively known, and may bear upon the stability of a superalloy under a protective coating. The binary phase diagrams Ni-Pt and Al-Pt, and the Ni-rich corner of the Ni-Al-Pt ternary, are reviewed and simple self-consistent thermodynamic models are derived. These thermodynamic models are incorporated into a database used to predict the gamma-gamma prime equilibrium for single crystal superalloys. In small concentrations, platinum is predicted to increase the temperature stability, but not the proportion, of the gamma prime phase over the gamma phase in third generation alloys such as CMSX-10. Another effect of platinum addition is to significantly lower the solidus temperature. These findings are compared to experimental data in the literature.

Jan 1, 2004

By M. Solomon

Abstract -Giant, sediment-hosted lead-zinc deposits in northern Australia formed during development of Mid-Proterozoic extensional basins that overlie Lower Proterozoic basement. The basement in the Mount Isa area, exposed by folding and faulting, contains fractionated, high-heat-producing granites. These granites generate heat at a rate of about 6 ?Wm-3, probably sufficient to form giant lead-zinc deposits either by (a) driving episodic convection of saline basement and basin fluids for periods of 105 to 106 years at temperatures of about 230°C, or (b) heating basin fluids moving under the influence of topographic relief or fault movement. The presence or absence of such granites may form a vital component of the genetic model. Ore-forming fluid flow was probably initiated by continent-scale, extensional basin fracturing.

Jan 1, 1992

By S. Theobald

Semi-finished copper and copper-alloy products are typically produced by casting, subsequent hot rolling or extruding and further cold working by rolling and drawing. The technological properties of the products depend not only on the chemical composition of the alloys but also on process parameters such as annealing conditions and degree of deformation. In each production step, measuring and control technology is an important tool for optimizing processes and ensuring constant high quality. This paper follows the product all the way from testing incoming scrap packages, chemical analysis of melts, mould level control in casting, non-destructive testing technologies in cold forming processes, controlling geometrical properties in the production process, to the final tests of technological properties. All test methods are focused on the applications and requirements of our customers, as the examples show.

Jan 1, 2007

By Marta Polgari, Eva Surova, Bohumil Molak

Abstract -The Ûrkút rhodochrosite deposit and Branisko Mn showings (rancieite, manganiferous calcite), located in Lower Jurassic marine sedimentary rocks with black shale, were studied by organic­ geochemical methods. Both depositionallocalities were affected by the Lower Jurassic Toarcian anoxic event. Ûrkút shales are rich in organic matter (av. 2.94 wt% total organic carbon), the composition of which indicates derivation mainly from marine sources, with some terrigenous component. The shales matured in a bacterially active environment under reducing conditions of diagenesis-catagenesis. Branisko shales (?0.2 wt% TOC) with lenses of Mn oxide ore were weakly metamorphosed and their organic matter thermally degraded. The model for Mn carbonate ore formation envisages reaction of Mn derived from sediments, with carbonate generated by a bacterially mediated process of decom­ position of organic matter that also involved Mn reduction.

Jan 1, 1992

By Andreea Catalina Gluhoi

Oxidation and reduction reactions of N-containing molecules have been studied over different types of gold-based catalysts, Au/MOx/Al2O3 and Au/MIOx/MIIOx/Al2O3 (M, MI, MII=Li, Rb, Mg, Ce, Zr, Mn, Cu) prepared by deposition precipitation with urea. In general, all the catalysts were already active at low temperatures. NH3 oxidation was effectively catalyzed by Au/CuO/Al2O3, a catalyst which also gives the highest yield in N2. NO reduction by H2 performed over gold-based catalysts produced N2O, N2 and NH3 and N2O reduction resulted in the formation of dinitrogen. For all the reactions, large synergistic effects have been obtained by addition of different kind of additives.

Oct 1, 2003

By G. Plascencia, A. Warczok, M. Zamalloa, T. Utigard, N. Behnood

The objective of this investigation was to investigate interactions between high-grade copper mattes and Rexal 60DB direct bonded basic bricks. The infiltration and attack of Rexal 60DB bricks by copper matte and continuous converter matte was investigated in laboratory tests at temperatures up to 1300 °C. The brick dissolution and infiltration tests did not show any significant difference between the 70% Cu and the 81% Cu mattes. More metallic copper was visible in the pores in the case of 81% Cu matte. An important mechanism for direct-bonded magnesia-chrome brick destruction is that oxysulphides start to infiltrate the brick, followed by slow oxidation of the matte producing metallic copper and cuprous oxide, which then react with MgO and Cr2O3, primarily attacking the direct bonds of the brick.

Jan 1, 2004

By R. A. Nemchek

Over the years, concentrator plant design has evolved from a large number of small grinding mills to a small number of large mills. In many cases, all of the tonnage runs through a single mill (typically a large SAG mill), so that the plant’s performance hinges on the productivity of this one machine. Industry specifications attempt to address the critical nature of today’s grinding mills in a manner that is often overly complex, neglects economics, and is not clearly focused on the end user’s goals. This paper surveys current industry practices, and proposes an improved approach to standards writing recognizing that product design, procurement, manufacturing, and quality are all inter-related in contributing to a project’s success. The lessons learned here can be extended to specifications for all types of machinery.

Jan 1, 2012

By Chih-Huey Lin

The Au/?-Al2O3 catalyst prepared by AuCl3 impregnation is subjected to the influence of residual chlorine after an oven drying. A post-impregnation NH4OH treatment was able to eliminate chlorine, and to reduce the cluster size of Au moiety. However, the CO oxidation activity was not increased by this post-impregnation NH4OH treatment. This suggests that certain metal-support interaction (MSI) is the determining factor for the activity of Au catalysts. Thermal treatment under H2, O2 or He was attempted to increase MSI of the prepared catalyst with or without the post-impregnation NH4OH treatment. No significant activity enhancement was found but the TPD analysis suggests that a H2 treatment has a higher chance to induce MSI.

Oct 1, 2003

By Brett Triffett, Mark Weidenbach, Christopher Treloar

OZ Minerals owns and operates the Prominent Hill copper-gold concentrator in South Australia, built in 2008 and commissioned in early 2009. The concentrator operates via semi autogenous grinding in a thirty four foot ThyssenKrupp Polysius mill followed by a twenty four foot Polysius ball mill in closed circuit with hydro cyclones, designed for an ore throughput of eight million tonnes per annum. The main aspects of designing the circuit are discussed along with the issues faced in the early stages of operation. A review of the optimization strategy applied to the milling circuit such as cyclone optimization, advanced process control strategy implementation and reline management to improve availability is then discussed highlighting areas of significant process improvement that have seen the plant exceed nameplate throughputs above nine million tonnes per annum.

Jan 1, 2012

By M. Solomon

Giant, sediment-hosted lead-zinc deposits in northern Australia fonned during development of Mid-Proterozoic extensional basins that overlie Lower Proterozoic basement. The basement in the Mount Isa area, exposed by folding and faulting, contains fractionated, high-heat-producing granites. These granites generate heat at a rate of about 6",Wm-3, probably sufficient to fonn giant lead-zinc deposits either by (a) driving episodic convection of saline basement and basin fluids for periods of IOS to 106 years at temperatures of about 230°C, or (b) heating basin fluids moving under the influence of topographic relief or fault movement. The presence or absence of such granites may form a vital component of the genetic model. Ore-fonning fluid flow was probably initiated by continent-scale, extensional basin fracturing.

Jan 1, 1992

By W. Dan Hausel

"Abstract-Hundreds of diamonds have been found in the United States. The majority of the discoveries occurred during the 19th century as a by-product of placer gold mining. Most of these early diamond finds have no known source, and in many cases are situated in areas unfavorable for diamond exploration based on current models that require kimberlite or lamproite to be emplaced in a stable Archean craton or Proterozoic craton margin.Diamonds have also been recovered in situ from lamproite at Murfreesburo, Arkansas, from kimberlite in the Lake Ellen region of Michigan, and in several kimberlites in the Colorado-Wyoming State Line district. Unverified reports also suggest that diamonds may have been recovered from other related intrusions at a number of localities in the United States."

Jan 1, 1995

By Eva Surová, Molák. Bohumil, Márta Polgári

The Úrkút rhodochrosite deposit and Branisko Mn showings (rancieite, manganiferous calcite), located in Lower Jurassic marine sedimentary rocks with black shale, were studied by organicgeochemical methods. Both depositional localities were affected by the Lower Jurassic Toarcian anoxic event. UrkUt shales are rich in organic matter (av. 2.94 wtOJo total organic carbon), the composition of which indicates derivation mainly from marine sources, with some terrigenous component. The shales matured in a bacterially active environment under reducing conditions of diagenesis-catagenesis. Branisko shales (~0.2 wt % TOC) with lenses of Mn oxide ore were weakly metamorphosed and their organic matter thermally degraded. The model for Mn carbonate ore formation envisages reaction of Mn derived from sediments, with carbonate generated by a bacterially mediated process of decomposition of organic matter that also involved Mn reduction.

Jan 1, 1992

By Robert J. McCarthy

Many technologies have been adopted over the last half century for the haulage of material from open pit mining operations. Some of the technologies utilized include rail, off-highway trucks, conveyors, and slurry pipelines - each having its unique application and benefits. Over time, truck haulage has become the primary means of surface mine material movement, though recently it has been plagued by problems of tire shortages, high diesel fuel costs, labour shortages, and carbon emissions. This paper focuses on In-Pit Crushing and Conveying (IPCC) as a competitor to truck haulage which has the potential to solve many of these problems. An overview of the available technology is presented along with measures required to overcome perceptional if not physical barriers to implementing this technology in modern open pit mines.

May 1, 2011

The Cadia mine is shifting from the open pit operation to the Cadia East underground block cave. The resulting increase in milled tonnes and the decrease in fines production through shifting to block caving require an increase of over 25% in installed power. This expansion is being accomplished via the installation of up-front crushing and HPGR milling of the ore, with the SAG mill receiving a secondary crushed feed. This design, criteria and rationale for selection is presented. Over the coming years, the mine will further expand capacity. The target is to accomplish this with minimal addition of installed power or use of fresh water. This presents a challenge that epitomizes the future constraints on our resource dependent and intensive industry. The approach and proposed options to this longer-term expansion are also presented.

Jan 1, 2012