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By Courtney A. Young

Cyanide is a fast-acting, highly toxic substance but, at the same time, is deemed essential for sustaining life as well 'as our standard of living. In this manuscript, the facts about cyanide are presented beginning with a brief history and definition and ending with a discussion on cyanide alternatives. Other topics include speciation, physical characteristics, toxicity, manufacturing, cyanogenics, cyanide cycle, separation, destruction, and markets including those outside the mining industry. Emphasis, of course, is placed on gold production by leaching and how it is influenced by ore type, mineral characteristics and economics as well as its advantages and disadvantages.

Jan 1, 1998

By Shigeo Asai

"Electromagnetic processing of materials is newly proposed to be considered as one of the engineering fields where functions of electromagnetism are utilized for processing electrically conducting materials, such as liquid metals, electrolytes and plasmas. The background requiring this processing and the engineering characteristics supporting it are described. The applicable functions of electromagnetism to material processing are revealed from the view point of magnetohydrodynamics. The existing processes and the proposed ones are classified into utilized functions and engineering applications are discussed. IntroductionElectric energy has been used in the metallurgical field for the processes of melting, refining and solidification. In these cases both the magnetic field which is induced by an imposed electric current, and the electric current are applied on electrically conducting materials such as molten metals. Thus, it turns out that the magnetohydrodynamic (MHD) phenomena have unconsciously been seen in metallurgical processes using electric current. The academic backbone studying MHD phenomena is the Magnetohydrodynamics which is being developed in the fields of plasma physics, astrophysics, fusion research and nuclear energy.The first attempt where magnetohydrodynamics was intentionally applied on metallurgy was a Symposium of IUTAM (The International Union of Theoretical and Applied Mechanics) in titled as ""Metallurgical Applications of Magnetohydrodynamics"" at Cambridge, UK, 1982 [1]. This timely event stimulated a few metallurgists to recognize the importance of ~MHD and was a good warning to the metal societies in the world. Especially in Japan, the Steelmaking Investigative Subcommittee of Research Planning Committee in the ISIJ (The Iron and Steel Institute of Japan) discussed the application of ~IHD to metallurgy and selected it as one of the four major innovative subjects for future steelmaking technology in Japan [2]. Indeed, the term of ""Electromagnetic Metallurgy"" itself was firstly coined by this subcommittee. Upon the request of a report from the subcommittee, the ISIJ has established a committee on ""Electromagnetic Metallurgy"" at 1985, under the author's chairmanship."

Jan 1, 1988

By D. R. Parker

"This paper canvasses emerging trends in public policy and law, which may influence the zinc industry's interest in recycling. There are forces at work beyond direct economic benefits that will drive recycling of zinc, including:• corporate determination to pursue sustainable practices and product stewardship.• public perceptions and pressure,• customer and investor demand,• workforce recruitment, and• protection and expansion of marketsIn this paper, these ""indirect"" forces are examined with particular focus on the zinc industry: It is concluded that, in today's world with an emerging precautionary approach to policy and law making, public perception concerning the environmental implications of metal products, and the need to conserve resources for future generation, a strong industry response is required."

Jan 1, 2000

By Enrui Dai, Weibing Chen, Bin Yang, Wenhui Ma, Haisheng Fang, Hui Wang

LiMn0.8Fe0.2PO4/C composite was prepared by an improved solid-state method and the effect of calcination temperature on properties of the obtained materials was investigated. The results showed that increasing calcination temperature from 600 to 700 oC improved the performance of the LiMn0.8Fe0.2PO4/C due to enhanced crystallinity and increased conductivity, but further increase in calcination temperature to 800 oC led to degraded performance due to particle growth and decrease in porosity. Therefore, the LiMn0.8Fe0.2PO4/C composite prepared at 700 oC exhibited the best electrochemical performance, and could deliver a high capacity of 152 mAh g−1 at 0.1 C, 147 mAh g−1 at 1 C and 114 mAh g−1 at 10 C. In addition, the performance of the LiMn0.8Fe0.2PO4/C and LiMn0.8Fe0.19Mg0.01PO4/C was compared when they were obtained at the optimum calcination temperature.

Jan 1, 2015

By Jie Li

Series of carbon compounds as anode materials were prepared for super lithium ion capacitor using graphite and active carbon (AC) as raw materials. Their electrochemical properties were investigated by constant current charge-discharge test. The results showed that the compound anode had good capacitive performance as well as Li-ion battery performance. The potential of the capacitor could be as high as 3.5V vs Li/Li+ when compared with 2.5V vs Li/Li+ in the AC-AC capacitor, accordingly, the energy density increased from 21.7Wh/kg to 40.3Wh/kg. The compound anode also had excellent rate performance that as the current density increasing from 0.1A/g to 1A/g,the capacitance decreased only 1.3F/g, and good cycle performance that the capacitance holding remained 96.7% after 10 times cycles even at the highest potential of 3.5 V vs Li/Li+.

Jan 1, 2009

By William K. Connor, O&apos

The U.S. Bureau of Mines (USBM), in cooperation with the American Society of Mechanical Engineers (ASME), conducted over 200 hours of melting tests to vitrify residues from five municipal waste combustion facilities. Combined residues (grate residue and f1yash) from three municipal waste combustors, a waste water treatment sludge combustor, and flyash from a refuse-derived-fuel (RDF) boiler, were sequentially melted in a I-metric-ton (mt) water-cooled-wall electric arc furnace. Each of the residues underwent magnetic separation, screen size analysis, and bulk chemical analysis prior to melting. The furnace products were examined by optical and electron microscopy and by X-ray diffraction. Bulk chemical analyses were acquired for the metal, fume, and vitrified furnace products. The material balance for the furnace operation indicates that from 69 to 86 pct of the feed reported to the vitrified furnace product, which had leaching potentials well below the EPA limit for each metal, as determined by the EPA TCLP. The electric arc melting furnace currently is being utilized in a cooperative research project between the USBM and the Idaho National Engineering 'Laboratory (INEL) for melting tests on simulated low-level radioactive wastes,

Jan 1, 1991

By Mark E. Schlesinger

Engineering design follows a six–step sequence. Demonstration of this sequence in materials engineering is less common. A case study is presented, using the 1989 paper by Gafner on the development of 990 gold-titanium alloy. This paper identifies a need, develops the problem, identifies alternatives, demonstrates the use of metallurgical principles to identify alternative responses, and shows how more favorable options are selected. The paper can also be used to illustrate engineering design as an iterative process. The paper is also useful as a starting point for more in-depth examination of specific elements of the design process, and lends itself to the creation of student exercises.

Jan 1, 2014

By Marcello M. Veiga

Informal gold mining operations in the Amazon emit about 100 tonnes of mercury annually because of poor amalgamation practice. Lack of information and the complexity of mercury transformations hinder effective action to prevent such pollution and/or monitor its extent. In the past, mathematical equations have been formulated to deal with the correlation of natural variables and mercury in biota but often, the error range is too great to provide useful models. Projection of physico-chemical variations in an environment subjected to mercury emissions onto the extent of bioaccumulation is fraught with many uncertainties and unknowns such as internal correlations between variables and the site-specific nature of biota contamination. Often assumptions about closed systems are invalid when applied to natural environments. This work presents a heuristic approach to this problem in which amalgamation methods and natural variables are dealt with using an IF-THEN rule-based system that concludes about levels of emission and risk of bioaccumulation. The system is able to handle uncertain or vague data and yet still provide useful output. Belief in mercury oxidation or dangerous conditions are examined using Fuzzy Logic techniques and Inference Equations. These belief levels are derived from thermodynamic equilibrium data together with field observations of natural variables. This procedure can reduce the need for sophisticated analytical equipment and can provide information and diagnosis to non-technical people.

Jan 1, 1994

By Corby G. Anderson

Antimony has been utilized by mankind for thousands of years. However, due to recent environmental concerns, antimony is often considered to be an impurity element, Since antimnoy is commonly found in precious metal refractory ore bodies, extraction is essential. The Sunshine Mine in Kellogg, Idaho has recovered antimony from its precious metal tetrahedrite deposits since the 1940's. A plant was initially constructed as a primary antimony source during World War II. This facility also decreased the downstream smelting penalty for the silver copper-lead concentrate and provided an industrial commodity from a potential environmental nuisance.' This paper describes the Sunshine antimony processing- facility. Specifically, the relevant process chemistries involved in concentrate leaching, metal electrowinning, and sodium antimonate production will be discussed. In addition, ongoing areas of research to improve unit operations and treatments implemented to meet environmental' discharge requirements will be covered.

Jan 1, 1992

By P. N. Anyalebechi

A comparative study of the mechanical properties of automotive steering knuckles produced by three different shape-casting related processes has been conducted. It involved the characterization of the tensile and fatigue properties of aluminum alloy A356 knuckles produced by the vacuum/pressure riserless casting (VRC/PRC), pressure counter pressure casting (PCPC), and the hybrid Cobapress (a casting-forging) processes, in accordance with the appropriate ASTM standards. Surprisingly, the knuckles produced by the hybrid Cobapress process exhibited the lowest strength. For example, the average 0.2% yield strength of the Cobapress knuckles was 31 MPa and 40 MPa less than that of the VRC/PRC and PCPC knuckles, respectively. However, between stresses of 150-200 MPa, the fatigue lives of the VRC/PRC, PCPC, and Cobapress knuckles were comparable. But above 200 MPa, the Cobapress knuckles exhibited the lowest fatigue life. The observed differences in the mechanical properties are attributed to the inherently different microstructures of the different knuckles.

Jan 1, 2009

By J. E. Hoffman

The operation of the U .S Metals Refining Company, USMR Co. is defined below by the description of a variety of unit processes and operations the author encountered during his tenure with the operation, 1955 - 1978. The operations discussed include: sampling and sweating of radiators, processing of Indian Coin, treatment of insulated wire, baghouse and converter dust treatment, blast furnace and converter operation, the electric arc furnace, antimony control, selenium and tellurium products, electrolyte liberation with soluble anodes, and the precious metals refinery. These operations, although peripheral to the primary copper production circuit, were critical to the company's technological and economic base.

Jan 1, 2000

By Markus Reuter, Antoinette van Schaik

In this paper the link between process metallurgy, classical minerals processing, product centric recycling and urban/landfill mining is discussed. The depth that has to be achieved in urban mining and recycling must glean from the wealth of theoretical knowledge and insight that have been developed in the past in minerals and metallurgical processing. This background learns that recycling demands a product centric approach, which considers simultaneously the multi-material interactions in man-made complex ‘minerals’. Fast innovation in recycling and urban mining can be achieved by further evolving from this well developed basis, evolving the techniques and tools that have been developed over the years. This basis has already been used for many years to design, operate and control industrial plants for metal production. This has been the basis for Design for Recycling rules for End-of-Life products. Using, among others, the UNEP Metal Recycling report as a basis (authors are respectively Lead and Main authors of report), it is demonstrated that a common theoretical basis as developed in metallurgy and minerals processing can help much to level the playing field between primary processing, secondary processing, recycling, and urban/landfill mining and product design hence enhancing resource efficiency. Thus various scales of detail link product design with metallurgical process design and its fundamentals.

Jan 1, 2014

By P. J. Mackey, J. B. See, D. G. C. Robertson

The production of iron and steel and non-ferrous metals by pyrometallurgical processes will remain a critical element in meeting the demand for materials in both developed and developing nations. Given the important need to reduce and minimise greenhouse gas emissions the technological focus of future pyrometallurgical R&D by universities and industry alike must concentrate on sustainability issues such as improved energy efficiency, recycling and waste minimization. Continued efforts are also needed on process optimization and new process development with a view to reducing capital and operating costs of the new large “mega” plants. Using the academic and industrial backgrounds of the authors, the present paper reviews the current status of R&D in pyrometallurgy in university departments with a particular emphasis on sustainability issues. The role of industry and government laboratories is also reviewed although primarily for developed countries. The paper also includes comments and suggestions on the future requirements for education and R&D in pyrometallurgy in developed countries to maximise sustainability. It is also suggested that future R&D in pyrometallurgy will be even more concentrated in developing countries – most notably China.

Jan 1, 2014

By Denise Crocce Romano Espinosa

The recycling of waste of electric and electronic equipment (WEEE) is one of the main modern challenges. Among the variety of WEEE, batteries can be set apart due to their composition and their growing demand along with portable devices. The objective of this work is to characterize the thermal behavior of a sample of mixed types of batteries using a thermobalance (TGA). The results of tests showed that Cd evaporated up to 800ºC, Zn evaporation occurred mainly above 900ºC and manganese oxides were pre-reduced to MnO at temperatures above 900ºC.

Jan 1, 2009

By E. Bélisle, Christopher W. Bale, S. Petersen, C. Robelin, K. Hack, J. Melançon, G. Eriksson, A. D. Pelton, P. Chartrand, S. A. Decterov, I. H. Jung, A. Gheribi

The FactSage® package consists of a series of information, database and calculation modules that enable one to access pure substances and solution databases and perform thermochemical equilibrium calculations. FactSage was originally founded by process pyrometallurgists and has since expanded its applications to include hydrometallurgy, electrometallurgy, corrosion, glass technology, combustion, ceramics, geology, environmental studies, etc. With the various modules one can perform a wide variety of thermochemical calculations and generate tables and graphs of complex chemical equilibria and phase diagrams for multicomponent systems. This paper presents examples of recent and current developments in FactSage in areas of particular interest to Dr. David Robertson. These include both ferrous and non-ferrous processing, as well as solidification and refining simulation. The paper also includes reference to the Internet Fact-Web education package.

Jan 1, 2014

By Vaughan R. Voller

"The wide range of length and time scales found in solidification processes are outlined and discussed. Methods for Direct Microstructure Simulation (DMS) are introduced. Key features in sharp interface and phase field models are presented. Concepts in micro-macro solidification modeling are covered. Basic details of microstructure and segregation models are provided. A description of a recent segregation micro-macro model is presented in detail.IntroductionA solidification process involves the containment of a liquid region, which, due to cooling, transforms over time to form a fully solid product. The development of the solid microstructure and the segregation of solute components during this transformation are controlled by phenomena that occur across a wide range of length and time scales. A ""successful"" model of a given solidification process needs to account for these phenomena. Standard models of solidification employ a discrete grid of node points and associated volume elements in the special domain, with a discrete time step to track the transient changes of nodal values, describing the composition and microstructure. Through the use of such models significant progress has been made towards a complete understanding of solidification process and phenomena (see the conference proceedings in Refs [1-9]). As solidification models become more sophisticated, however, they all run into the problem of resolving the full range of disparate space and time scales.Two approaches can deal with this problem1. Direct Microstructure Simulation (DMS) where the grid size and time step are chosen to scale with the smallest length and time scales of the given problem.2. Micro-macro modeling where the grid size and time step scale with the macroscopic process scale and phenomena at smaller scales are accounted for via sub-grid modeling and volume averaging.Currently full DMS of solidification is beyond the reach of available computer power and the application and development of micro-macro models is an important and critical research area."

Jan 1, 2001

By W. Kunda

Silver nitrate solution is a very common product in hydrometallurgical processes involving the treatment of various silver bearing materials. Silver is recovered by electrolysis. The alternative method for the recovery of silver from aqueous solutions is the precipitation by hydrogen at elevated temperature and pressure. A previous study by the authors revealed the feasibility of this technique for the silver ammine sulfate system. Further study showed different behavior for silver in the silver ammine nitrate system and a systematic study was initiated to establish the optimum conditions for the process. The study showed that the process can be controlled by (1) composition of the feed solution, (2) temperature and (3) hydrogen pressure. The recovered silver product was in the form of very fine powder.

Jan 1, 1989

By R. W. Smith

Living and killed organisms, particularly microorganisms, and extracellular products derived from the organisms are increasingly finding use in minerals engineering. Goals include both enhancement of mineral processing/11.ydrometallurgica,l operations and remediation of mineral industry wastes. Some of the applications, such as biologically assisted leaching of ?sulfide ores and bioxidation of refractory gold ores, are well established commercial ?processes used around the world. Others, such as the use. of organisms for the removal of heavy metal ions from dilute aqueous streams, are nearing commercial application. Many other uses of microorganisms and. their derivatives are potentially possible. These include use of microorganisms in flocculation or flotation of minerals., remediation of organics potentially discharged from mineral engineering operations, degradation of cyanide, the recovery of bitumen from heavy oil reservoirs and tar sands and the solubilisation of lignites and low rank coals. In order to fully exploit these many possible uses of organisms and their derivatives, extensive fundamental .and .applied research work exploring the fundamentals, potential and practicality of the various possible uses of microorganisms in mineral engineering should be vigorously pursued. ?

Jan 1, 1991

By Ramona Prillhofer

Salt slag is a waste product produced by the recycling of aluminum. In most European countries (e.g. Austria, Germany) the landfill disposal of this waste is forbidden because the slag contains soluble salts and these represent a potential source of pollution to the surface and groundwater. Additionally, consisting metal and some compounds in the salt slag can react with water and resulting from this, noxious gases are generated. The recovery of useful materials from these wastes is accordingly both environmentally necessary and economically feasible. This study describes a complete recycling-process for the salt slag, which includes a leaching-cristallization-process to obtain the oxidic residue, a pyrometallurgical-step to clear the oxidic residue and finally an extensive characterization of the achieved products. Due to the increasing price of raw materials, the utilization of the oxidic residue into commercial products has been investigated and application possibilities will be discussed.

Jan 1, 2009

By C. E. M. Meskers

Electronic and Electric Equipment contains a range of components made of a wide variation of metals, plastics and other substances. Up to 60 elements can be found in complex electronic equipment: base metals, precious metals and special metals in circuit boards and batteries. Because of its amount WEEE represents a considerable metal resource with a higher special and precious metal content than found in ores. The Umicore integrated smelter and refinery recovers and supplies back to the market 17 different metals from EEE. Pre-treated materials enter state of the art, material and energy efficient metallurgical processes for environmentally sound recovery of metals and treatment of off gasses and hazardous substances. The organics in the feed function as reducing agent and alternative energy source during smelting for precious metal recovery. Lithium-ion batteries are treated using a dedicated process. As a result the environmental footprint of metals produced from EEE is much smaller than primary production.

Jan 1, 2009