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By Elli Nurminen

Fouling of heat recovery process equipment may significantly decrease their heat transfer efficiency. In Copper Flash Smelting process flue dust tends to form build-ups on the heat recovery boiler walls. Thermal transportation properties of copper flash smelting flue dust and its components have been studied. The effects of porosity and temperature on thermal transportation properties have also been determined. The results indicate that dust and its components are effective thermal insulators and build-up layers on the boiler walls are likely to decrease greatly the heat transfer efficiency of the boiler. Decreasing dust layer porosity has a strong increasing effect on thermal conductivity and increasing temperature has a slight decreasing effect on thermal conductivity. The results may be used in CFD-modelling and optimisation of the process.

Jan 1, 2006

By C. Camurri

Results from the Metallurgical Department of Universidad de Conception showed that fire-refined copper could be rolled without previous remelting for deoxidation. The goal of this work is to determine the rheology of fire-refined copper from tensile tests at different temperatures and strain rates, and Ford plane compression tests. All that in order to simulate and calculate rolling process variables. For rheology hardness coefficients, n variables between 0.28 at 600°C and 0.46 at ambient temperature are obtained. The sensibility coefficient for strain rate m varies between 0.056 at 600°C and 0.006 at ambient temperature. The activation energy for plastic flow Q in the considered temperature range is 1436 cal/mol.

Jan 1, 1999

By Yoshiaki Suzuki

In 1996, Saganoseki smelter & refinery successfully shifted to a single flash smelting furnace operation and increased the copper production capacity to 450,000mtpy in 1998. As the next step, Saganoseki planned to further increase the productivity in the smelting process. Applying the latest technology and carrying out technological innovations the throughput of the flash smelting furnace has been increased to 195 tons per hour and the matte grade has been raised to 68%. In 2005, six PS converters have been successfully consolidated into four by maintaining the production capacity. This paper introduces recent operation conditions and results of implementation of technological improvements.

Jan 1, 2006

By D. A. R. Kay

Phase stability diagrams are used to predict the abilities of lanthanum and cerium oxides to desulfurize coal gasification products in the temperature range 800-1000 C. Results of desulfurization studies in laboratory fixed bed reactors illustrate the effects of i) sorbent preparation, ii) input gas quality and iii) temperature, on the desulfurization reaction. 2CeO(2-x)(s) + H2S(g) + (1-2x)H2 = Ce2O2S(s) + 2(1x)H2O(g) The results of desulfurization/oxidation regeneration cycles are also reported.

Jan 1, 1989

By V. Bhagavathy

This paper describes a method for the determination of traces of rare earths using energy dispersive x-ray fluorescence spectrometry (EDXRF) after preconcentration of their oxine complexes onto activated carbon. Various parameters that influence adsorptive preconcentration of rare earths onto activated carbon viz. pH, amounts of activated carbon and oxine, time of stirring and aqueous phase volume were systematically studied. A numerical method based on simple least square procedure using fifth order polynomial with 25 consecutive values was developed for smoothing and differentiation of EDXRF data which was previously digitized and averaged. First order derivative EDXRF in conjunction with adsorptive preconcentration on activated carbon enables to determine as low as 10 ppb of each of individual rare earth elements.

Jan 1, 1989

By V. I. Lakshmanan

Whilst the prices of metals in nominal terms have largely remained static over the past forty years, in real terms, the primary metals industry receives very much less today for its products than in the past. Yet, it has largely managed to remain competitive, despite the fact that ore reserves are not only diminishing, but are of lower grade and higher complexity, and that there are much greater pressures on companies to be good environmental stewards. This paper examines how hydrometallurgical processing has shown itself to be highly innovative in order to remain viable both economically and environmentally. Aspects of process chemistry are discussed, and the lessons to be learned from having a good understanding of this chemistry are highlighted with reference to a number of case histories such as HPAL for nickel laterites, the Avmin/Chambishi Cosac Project, use of chloride chemistry for titanium extraction, and plant effluent treatment and recycle.

Jan 1, 2003

By B. C. Curson

A comprehensive simulation of .the gas handling system in BHP Copper's San Manuel smelter was developed using AFT Fathom software, with the objective of minimizing SO2 emissions while maximizing smelter throughput. Once verified with plant data, the simulation quickly revealed' the complex interactions occurring between individual converters and the flash furnace. The increased understanding provided by the simulation allowed novel, counter-intuitive control strategies to be developed and tested successfully.

Jan 1, 1999

By James A. Sommers

Combustion of niobium nitride powder in a stream of oxygen results in several niobium oxide phases, depending upon reaction parameters. Under rapid oxygen flow, the oxidation produces a molten mass which coalesces into droplets of ca. 2 mm dimension and effectively quenches to leave NbO2 and other lower oxides of niobium, despite the ambient atmosphere of oxygen. A preliminary survey of reaction parameters which govern the split between reduced and oxidized products is presented. This technique offers novel synthesis means for binary oxides when mixtures of NbN and other materials are combusted together, since the niobium moiety is generated in a molten state.

Jan 1, 1995

By Chunlin Chen

Published data on thermodynamics of a number of minor elements (As, Sb, Bi, Pb, Zn, Se, Te, Cr, Sn) in liquid copper, matte and slag have been reviewed, assessed and used in development of thermodynamic solution models of melts. The behavior of antimony in alloys, mattes and slags is used as an example to illustrate the approach taken in assessment of published data and validation of the developed models with respect to the activity of Sb in condensed phases as well as the effects of matte grade, slag chemistry, temperature etc on the equilibrium distribution of Sb between melts and the gas phase. Results obtained from a comparison of different smelting processes with the modeled multi-phase equilibrium are presented and discussed. The predicted effects of slag chemistry and matte grade on the deportment of other minor elements during smelting of copper mattes will be presented and discussed.

Jan 1, 2006

By Christian Hecker

An Eh-pH electrochemical sensor developed for on-line pH and redox potentials copper sulphide flotation process control was studied. The electrochemical sensor cell includes two metallic platinum electrodes, a metallic antimony electrode and a high impedance reference cell which are polarized with a potentiostat. For pH and redox potential determinations, the Sb and platinum electrode potentials are measured, respectively, against the polarized electrochemical reference system. The behaviour of this electrode configuration has been investigated in a laboratory scale. An electrochemical sensor device has been succesfully installed and checked in El Teninte Colon Concentrator's SAG line feeding the copper flotation rougher circuit.

Jan 1, 1999

By E. Gervais

Modern life in inconceivable without zinc. Zinc provides the most cost-effective and environmentally efficient method of protecting steel from corrosion. Zinc is also used to power electric vehicles and computers, to make brass, automotive equipment, household appliances, fittings, tools and toys, and to support the building and construction industries. It is also used in pharmaceuticals and cosmetics, in rubber, in fertilisers and in animal feeds. The links between properties, applications and performance, as well as zinc demand and market dynamics, will be reviewed along with market development opportunities and successes. The presentation will also include a progress report on the five-year plan of the International Zinc Association to increase the global market for zinc, over and above the natural growth, by 500,000 tonnes/year by 2002.

Jan 1, 2000

By John L. Uhrie

Oxide stockpile leaching operations can realize increased copper recovery and decreased acid consumption from in-situ generated acid resulting from the oxidation of intentionally introduced pyrite recovered from mill tailings or other sources. While all oxide leach ores can benefit from pyrite addition, low acid consuming ores can show remarkably increased recovery and net acid generation; however, more highly acid consuming ores will show benefit more exclusively through increased copper recovery. Additional work shows that the value of highly acid consuming ores can be optimized by balancing copper recovery against acid consumption.

Jan 1, 1999

By J. Riccardi

Copper refineries use massive copper castings as moulds into which impure molten copper from the reverberatory furnace is poured to form anodes for further electrolytic refining. To facilitate removal of the copper anodes from the mould and to prolong the life of the mould itself, it is traditional to spray the mould surface prior to each use with a slurry of baryte in water. This slurry application leads to poor housekeeping, operating costs are escalated by the cost of the slurry, and additional problems in the subsequent refining process are experienced due to carry-over of excess undesirable baryte powder. A one-time application of a diffused layer of aluminum to the surface of the copper mould prior to putting the mould into service has been found to provide extended mould life and facilitate anode removal, as well as reducing baryte consumption; thereby reducing operating costs at both the anode manufacturing and refining stages.

Jan 1, 1999

By Javier Antoñanzas, Juan Carlos Múgica, Lourdes Yurramendi

The gasification of wastes containing an organic fraction is usually performed at low-medium temperature using different kind of catalysts. The off gas obtained is a mixture of carbon oxides, mainly carbon monoxide, and hydrogen and can be used for different energetic applications. The main problem is the production of tars in the off gas that has to be separated from the valuable gas flow and, finally, treated separately. An interesting alternative is the partial or total treatment of organics at high temperature. In this case, the off gas contains a higher content of hydrogen and elemental carbon as particulate matter. The energetic source to obtain a temperature in the range of 1,000 - 1,200 ºC is obtained by a plasma torch. In order to make de process attractive, an important issue to be considered is to commercialize the carbon obtained for different industrial applications.

Jan 1, 2008

By R. Chiarizia

Third phase formation, i.e., the splitting of the organic phase in two layers, is a common feature observed, under conditions of high loading, for many solvent extraction systems of both analytical and industrial interest. Although this phenomenon has been investigated in a large number of works, a structural and physico-chemical description is still lacking. In this work, small-angle neutron scattering (SANS) data for the tri-n-butylphosphate (TBP)-n-octane,Th(NO3)4-HNO3 solvent extraction system have been interpreted using the Baxter model for hard-spheres with surface adhesion. The increase in scattering intensity in the low Q range, observed when increasing amounts of HNO3 and/or Th(NO3)4 are introduced into the organic phase, has been interpreted as arising from interactions between small reverse micelles containing three TBP molecules plus solutes in their polar core. This intermicellar attraction, under appropriate conditions, leads to third phase formation.

Jan 1, 2003

By Luis G. S. Sobral, Gabrielle N. Bard

Copper sulphides Concentrates, from the flotation process of copper primary ore; contain, commonly, small amounts of precious metals, such as gold and silver. During the smelting process of those concentrate all gold and silver are practically in the blister copper, which is cast into anodes. Those copper anodes are electrorefined in an electrolytic system, where the electrolyte is an acid copper sulphate solution, where a high purity electrolytic copper is produced (>999,9/1000). The slime when submitted to an oxidative leaching process, using sodium hypochlorite and hydrogen peroxide as oxidizing agents, turn those metals into solution. This research practical work, apart from concentrating effort on the digestion of the anode slime, aims at evaluating the efficiency of the cementation process of the metals of interest for the separation of them to take place. 141

Jan 1, 2008

By T. N. Chan

This paper provides some general discussions on the development of a new beneficiation process for the treatment of a highly complex monazite orebody located at Mt Weld, Laverton, Western Australia. The complexity of this rare earth ore and the associated problems encountered in ore preparation, desliming and flotation in beneficiation during the development study stage and the solutions to these problems are reviewed.

Jan 1, 1992

By J. Murphy

The economics of microbial coal desulfurization are affected significantly by the proper selection of the plant site and by maintenance of variables at suitable levels. High sulfur coal particles below 200 mesh show sulfate production rates triple those with 150 mesh coal but grinding costs are greater. Slurry solids density increases from 5% to 20% reduced the rate constant by a factor of 10. Coal added to a batch reactor in the stationary phase resulted in a sudden second exponential sulfate production phase indicating feasibility of lower cost continuous operation. Successful operation in the absence of beef broth, yeast or added nutrients at non-sterile conditions enhanced projected economics. Finally, the need for adequate agitation and aeration was well established.

Jan 1, 1985

By M. Hashiuchi

In 1972, the tankhouse of the Tamano Smelter adopted a high current density electrolysis operation applying the PRC (Periodic Reverse Current) method. In 1994, the phase four production expansion project, which incorporated significant re-structuring of the organization, was completed and we have achieved an annual production capacity of 191,000 tons. The target of this project, the production capacity, was increased by 1'8% and labor productivity by 25%. After the expansion, some improvements in the starting sheet section and the verticality of the electrodes were carried out, and the efficiency of the operation was greatly enhanced, including the improvement of the quality of the electrolytic copper.

Jan 1, 1999

By Victor Bredykhin

The reasons of formation low quality cathode deposits and conditions of the anode passivation in electrorefining of copper silver alloys with increased (more then 5%) silver content in electrolyte, g/l: Cu - 40; H2SO4-50; 150 and 250; T= 401C have been investigated. As it is shown, increased acidity, anodic current density and silver content in anodes favor passivation. The assumption is made that the ingress of silver on cathodeis the most probable reason of growing dendrites on cathode. We have determined that addition of ethylene carbonic acid to electrolyte in the amount of 3,5 ÷ 10 ml/l suppresses the dendrite formation.

Jan 1, 2006