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By F. Guevara

The paper presents results of physical and turbulent three-dimensional numerical simulation of the gas flow in the wind box and reaction shaft of the concentrate burner of a flash furnace. Physical simulation work was carried out in a 1:5 linear scale model, where the velocity field was measured using a Pitot tube. The mathematical model consists of the three-dimensional averaged Navier-Stokes equations, turbulent kinetic energy and dissipation of turbulent kinetic energy using the Renormalization Group (RNG) theory for the k-e turbulence model. Computations were performed using FLUENT, based in a finite- volume code. The geometry of the concentrate burner was separated in two sections: wind box and reaction tower. Results obtained at the exit of the wind box were used as boundary conditions for the reaction shaft. The effect of boundary conditions on the numerical results was also studied. Results of physical and numerical simulations show an asymmetry of the velocity field at the exit of wind box. This asymmetry is possibly due to existence of a separated flow in the back of the exit ring. The agreement of physical and numerical results assess the capacity of the turbulence RNG k-e model to reproduce correctly the behaviour of the velocity field at the exit of the concentrate burner.

Jan 1, 1999

By L. Béjar-Gómez

The aim of this research work is to study and characterize precipitates in structural microalloyed steel by transmission electron microscopy and analysis by high resolution (HRTEM). Microalloyed steel with titanium was produced by casting in an electrical induction oven of 25 Kg. capacity. Carbon content in steel was less than 0.1 % and titanium content of 0.04%. Steel was processed thermomechanically; reheated to 1250ºC and hot rolled on a laboratory mill to a 13.0 mm thick plate with a finish rolling temperature of 900ºC and thickness reduction of 80%. Analysis by High Resolution Transmission Electron Microscopy (HRTEM) identified precipitates in the steel; type and morphology. Energy Dispersive Spectroscopy (EDS) analysis was applied to obtain the chemical composition of precipitates and the matrix. STEM-EDS analysis was also applied to obtain the element profile of precipitates. The results showed the presence of carbonitride precipitates of titanium, Ti (CN), with a circular morphology and size of 10 nm and less.

Jan 1, 2006

By James R. Myers

A source of clean gas containing sulfur dioxide and sufficient oxygen for conversion to sulfur trioxide is essential to the production of sulfuric acid. SO2 containing gases obtained from roasting sulfide ores are heavily contaminated with inorganic dust and volatile impurities. If not removed, these contaminants will reduce product acid quality, foul the catalyst beds and mist eliminators, and accelerate equipment corrosion. This paper reviews conventional gas cleaning systems for metallurgical acid plants, followed by a discussion of modern systems utilizing DynaWave Scrubber technology. This technology is based on a unique approach togas scrubbing that can concurrently accomplish several gas cleaning/processing tasks. Scrubbing liquid is injected into the gas stream to create a "Froth Zone". This is a region of extreme turbulence, with a very high rate of liquid surface renewal. It efficiently removes both particulate matter and gas contaminants, and is also a cost effective quenching device for gases as hot as 1250 o C.

Jan 1, 1992

By J. C. Agarwal

Rare earth metal alloys are becoming increasingly important, particularly those of neodymium, because of their magnetic properties. This paper will present a generalized approach to the production economics of the metallic rare earth alloys. With appropriate regard for the chemistry of different rare earths and the large impact of economies of scale, it is possible to make fairly accurate estimates of the production costs of other rare earth alloys as well.

Jan 1, 1989

By Tomas Astorga

APEC, the Asia Pacific Economic Cooperation is the forum of 18 economies, having a combined GDP of approximately 56% of the total world income, and over 45% of global trade. Its mining sector produces a large portion of the main minerals and metals in the world. In 1997, APEC economies produced 67% of world copper output, 55% of gold, and over 45% of other base metals. Mining in APEC captures more than 60% of the total mining investment in the world. Against this background, the Expert Group on Minerals and Energy Exploration and Development, in short GEMEED, was created in 1996, under the auspices of the APEC Energy Working Group. The sustainable development of mining activities is a main concern in APEC and GEMEED. Several programs related to the subject are actively being pursued by the Expert Group. Among them, it should be noticed the creation of an Environmental Cooperation Sub Group coordinated by Japan, whose main aim is to encourage proposals related to the environmental soundness of mining projects in the region. Also, it should be noted the existence of a Database Steering Committee whose focus is the development of an information network related to mining opportunities in the region GEMEED is a gathering of experts from all the APEC economies. As such, it represents a privileged forum to discuss policy issues related to mining. On this regard, the paper focuses on concrete actions taken by GEMEED to enhance the sustainability of the copper activity in the region.

Jan 1, 1999

By H. Forrest

Lead smelting at Cookson Industrial Materials was formerly carried out using a combination of Blast and Reverberatory Furnaces. In the late 70' s these furnaces were replaced by two 20 tonne capacity Rotary Furnaces. This furnace type has proved to be more flexible in the range of feedstock that can be processed, including lead drosses, battery plate and even whole batteries. High rates of production have been achieved whilst attaining a good level of environmental control. The majority of the sulphur in the feedstock can be fixed by use of appropriate fluxes.

Jan 1, 1990

By P. A. Olubambi

The effect of ore mineralogy on the bioleaching of metals from complex sulphides was studied by investigating the bioleaching of zinc and copper from a bulk complex sulphide ore from Ishiagu, Nigeria, using mixed cultures of Thiobacillus ferrooxidans, Thiobacillus thiooxidans and Leptospirillum in mechanically stirred reactors at varying particle sizes. Mineral phases within the varied particle sizes of -53, 53, 75 and 106µm were identified using X-Ray Diffraction (XRD), while the elemental distribution within the varied particles sizes was determined by X-Ray Fluorescence (XRF) and Optical Emission Spectrometry using Inductively Coupled Plasma- Optical Emission Spectrometer (ICP-OES). Bulk ore and the leached residues were examined by X-Ray Diffraction. The highest bioleaching recoveries were obtained at particle size of 75µm, while particle size of 106µm gave the least recoveries. Lower recoveries at particle sizes of 53 and -53µm were as a result of their higher silica and siderite content which affects pH, iron mobility and oxidation.

Jan 1, 2006

By P. K. Narasimhargahavan

This paper discusses briefly the major reasons associated with the growth and its impact on the energy requirement and Environmental imbalance. A projection based on the present global Alumina and Al requirement indicate a substantial further growth of at least 30% over the next 10 years. It is indicated that the main factors which are likely to influence investments are the environmental factors such as the Climate Change and global response to the growing energy prices and sustainable development. Each of the developed / developing nations must find response to the GHG emissions which will encourage the Al Industry to make an effective contribution to global warming while preserving the international competitiveness of the industry - a challenging task. The efforts shall concentrate on improving energy efficiency in the industry possibly of the order of 25% over the next 10 to 20 years. The developments in this line are discussed.

Jan 1, 2010

By W. E. Wallace

Rare earth elements combine with most, of the metallic elements. As early as 1971 over a thousand intermetallics had been identified and described(1) From a magnetics viewpoint, systems involving. the d-transition metals Fe, Co and Ni are particularly interesting. In these systems there are at least four significant interactions: R-R exchange (R - a rare earth), R-T exchange (T = a transition metal), R-R exchange and the crystal field interaction acting upon the. rare earth ion. There is complex interplay between these interactions leading to bewildering variety in their magnetic behavior., Because of this and in view of the commercial significance of some rare earth intermetallics, studies of these systems has been an unusually active area of inquiry for the past two or three decades. The large magnetic moment of many of the rare earths, viz., 10 µB per atom for Dy and Ho, 9 1B for Tb and Er, etc., attracted, attention many years ago to the rare earths as potential ingredients for alloys to be used in permanent magnet fabrication. The utility of a permanent magnet in high perform¬ance devices (travelling wave tubes, voice coil motors, brushless motors, etc.) is in large measure determined by its maximum energy product, (BH)max. [(BH)max is the maximum value of B (magnetic induction) and H in the 2nd quadrant of the hysteresis loop.] Enhanced atomic moment in princple can lead to increased B and a large maximum energy product. Until about 1970 the largest (BH)max value known was about 5 MGOe(mega-gauss Oersted). This was for A1NiCo - an alloy involving Al, Ni and Co. It was recognized that the rare-earths had the potential for much higher energy product; in the case of Dy the theoretical energy product is about 35.0 MGOe., 70 times that of Alnico. (Needless to say, this theoretical value has never been achieved.) Large-scale efforts began about 30 years ago to synthesize magnetic materials containing rare earths and which would be suitable for permanent magnet fabrication. It was recognized by Strnat(2) et al. that a material to, be useful in high energy magnet fabrication would have to satisfy three. criteria:

Jan 1, 1992

By K. Noda

Tamano Smelter of Hibi Kyodo Smelting Co., Ltd. is carrying out a low cost production using a Tamano Type Flash Smelting Furnace (T-FSF), which is an improved version of Outokumpu Type Flash Smelting Furnace but without slag cleaning furnace and also by developing its own coke combustion technology. Coke combustion technology that is the basis of the system has been improved several times and, at present, it has evolved to a stage where it can be reproduced on the Computer guided system for Coke Combustion in the T-FSF (CCCT) using a general- purpose computer. This CCCT is featured by 'its trend control and predicting function, and an operator can freely control the operation parameters so as to control the operation flexibly. We have recently developed an overall energy reduction system covering the Smelting Plant to Sulfuric Acid Plant, which we call an Optimum Low Cost Operation System (OLCO) to reconsider the energy costs including coke, heavy fuel oil, and electric power. In this report, we would like to present the recent operation of T-FSF based on CCCT as well as the optimum energy operation utilizing OLCO system.

Jan 1, 2002

By W. G. Davenport

Chapter 13 evaluated the %02 in blast, industrial oxygen and oil requirements for smelting FeSrCuFeS2 concentrates~ This chapter examines high eu grade CU2S-CuFeS2 concentrates the same way.

Jan 1, 2001

By P. M. Pincheira Brown

The widely accepted inverse relationship between copper prices ail stocks, has been commonly used by analysts to explain the behavior of the copper market and to forecast film copper pries. However, empirical data have not shown such a clear relationship between copper prices and stacks. Existing evidence only indicates a weak tong-nut relationship that vanishes in some periods. In this paper a simple comprehensive model is provided which explains both parallel and opposite direction movements between prices and stocks. Former are explained mainly by stocks demand expansions-contractions while the latter are in essence due to increases in the supply curve. Furthermore, econometric estimations are provided, thus giving a powerful tool to forecast and explain price developments of the copper market.

Jan 1, 1999

By L. N. Ertzeva

The present work is dedicated to investigation of the sulfidizing process of ore pyrrhotite concentrate with recovery of a sulfide material, enriched with non-ferrous metals, and waste pyrite, with downstream separation by a certain beneficiation method.

Jan 1, 2006

By Catherine Williams-Beam

Thallium is more toxic to humans than mercury, cadmium, lead, copper or zinc. Its chemical behavior resembles the alkali metals (K, Rb, Cs). It occurs almost exclusively in natural waters the monovalent thallous cation. The solubilities of thallous compounds are relatively high so that monovalent thallium is readily transported through aqueous routes into the environment. The major sources of thallium are the base metal sulfides and precious metal bearing sulfides. Therefore, it is often present as a contaminant constituent in waters emanating from heavy metal sulfide bearing deposits. Thallium can be effectively removed from wastewater to <2 µg/L by reductive precipitation of thallium sulfide. Effective thallium sulfide precipitation requires a controlled solution potential/pH combination. The required potential can be effectively achieved by utilizing a particulate iron slurry or packed column environment. Experimental results will be presented and discussed.

Jan 1, 2003

By D. N. Collins

A sampling program was conducted in which both spoon and isokinetic sampling techniques were used to collect samples from the reaction shaft. The samples were then characterised by chemical, XRD and mineralogical analysis. Further information was acquired by measuring the oxygen potential and temperature at the bottom of the shaft using disposable probes. Comparison of the results of the two sampling methods showed that the spoon samples were devoid of material less than 25 m. Sulfur analyses on the samples provided information on the extent of reaction, plume shape and recirculation patterns. Disposable probe measurements showed the measurable particle temperatures ranged from 1150 to 1700 °C and that the material falling into the bath had a normalised oxygen potential similar to the slag. These latter measurements combined with the sulphur elimination and mineralogical analyses provided further information on the extent of reaction and enabled the reaction sequence to be ascertained.

Jan 1, 1999

By Theo Lehner

Nasty, according to the Collins Dictionary, comprises the adjectives: bad, critical, dangerous, dirty, odious, serious, severe, sickening, unpleasant etc. From this we may at first conclude that each individual smelter relying on its own specific business surrounding would have a special definition of its nasties. But common product standards and common metallurgy makes us experience common nasties. To get an idea of possible problem elements we start with the demands on the products: [ ]

Jan 1, 1994

By S. D. Prosser

The earliest record of slag in the world was the discovery of the remains of a copper blast furnace in Southern Israel, which has been carbon dated at 3500BC, nearly 6,000 years ago. Slag in Australia is a much more recent phenonenum with the first iron blast furnace commencing operations in 1848. The early days of metal smelting in Australia were marked with many company failures due to a variety of reasons. This paper traces the progress of metal and slag production from those early days up to the present times

Jan 1, 1994

By Florian Kongoli

Minor components and flux additions can modify the liquidus temperatures of multicomponent slags. In industrial practice, slags with various levels of minor components require various flux additions in order to achieve the lowest possible liquidus temperature The prediction and the optimization of these combinations can decrease the cost of the overall process. In this work the effect of several minor components and flux additions such as Al2O3, MgO, and CaO, on the liquidus temperatures of multicomponent iron-silicate slags has been analyzed in terms of a thermodynamic model Various simple isothermal and non-isothermal diagrams are presented. These diagrams can be used directly by the process operators to define the optimum conditions under which the fluxes can be used to achieve the desired slag liquidus temperatures.

Jan 1, 1999

By L. H. Lewis

The relationships that link microstructural properties of advanced permanent magnet materials with magnetic properties such as the coercivity are often difficult to quantify, especially in materials with nano-scale structures. Recent work on RE2Fe14B-based powders fabricated with rapid- solidification techniques such as inert gas atomization (IGA) and melt-spinning provide insight into the nanostructural features which affect the acquisition and stability of coercivity. In all cases the coercivity is found to be a function of both the scale of the constituent microstructure and of the presence and distribution of minor phases.

Jan 1, 1997

By David B. Dreisinger

The total pressure oxidation treatment of arsenical copper ore and concentrate from the El Indio mine of Banick Gold was tested in benchtop autoclave treatment. The concentrate oxidation typically achieved ~95% copper extraction. Copper extraction was limited by the reprecipitation of a complex precipitate containing arsenic. Gold extraction by cyanidation of the oxidation residue was around 95%. Silver extractions were less than 10% due to the formation of argentojarosite in the autoclave. The total pressure oxidation of the whole ore sample was more successful. Copper extractions of 98-99% were routine achieved. Gold extraction by cyanidation was +95%. Silver extraction could be increased to as high as 95% by using the lime boil treatment. A process flowsheet was proposed based on the results achieved. Copper recovery was proposed by direct solvent extraction and electrowinning of copper by treating the dilute solution from the autoclave discharge.

Jan 1, 1999