Sponsored by: EPD Copper, Nickel, Cobalt Committee
Program Organizers: Norbert L. Piret, Piret & Stolberg Partners, Im Licht 12, D-47279 Duisburg, Germany; Ivan M. Santos Moraes, Caraíba Metais, Dias D'Ávila, Bahia, Brazil
Tuesday, PM Room: A11-12
February 6, 1996 Location: Anaheim Convention Center
Session Chairpersons: J.F. Castle, RTZ Technical Services Ltd., PO Box 50, Castlemead, Lower Castle Str., Bristol, BS99 7YR, UK; J.E. Hoffmann, Jan H. Reimers & Associates, PO Box 420545, Houston, TX 77242-0545
2:00 pm Invited
CODELCO-CHILE'S CORPORATE DECONTAMINATION PLAN FOR ITS SMELTERS: Gerardo Muñoz, Codelco- Chile, Corporación Nacional del Cobre de Chile, Huerfanos 1270, Casilla 150-D, Santiago de Chile
All along this century Codelco's smelters have been operating on conventional technology, which Codelco has streamlined by using oxygen, developing oxy-fuel burners for reverberatory furnaces and introducing oxygen smelting of concentrates in converters (Teniente Converters). Chuquicamata began capturing sulfur from its first Teniente Converter in 1985. Since then, it has implemented a program allowing to gradually increase such capture. In 1994 a Frame Law on the Environment was enacted in Chile. By virtue thereof and of Codelco's corporate environmental policy, an investment program aimed at capturing more than 95 % of gaseous pollutants in all its smelters in a term not exceeding twelve years was established. The above entails a substantial improvement of the operational management as regards fugitive gases capture and treatment. This paper describes the way Codelco is to deal with this challenge with a view to fully complying with environmental regulations and obtaining the required environmental certifications of its operations.
2:30 pm
ENVIRONMENTAL MANAGEMENT MEASURES RELATING TO A GREENFIELD COPPER SMELTER: Norbert L Piret, Karl H Schmidt, Piret & Stolberg Partners, Im Licht 12, D-47279 Duisburg/Germany
From the copper smelter operation various outputs are likely to exert negative impacts on the environment. Particularly, emissions like SO2 and dusts, solid wastes like contaminated gypsum and arsenic sludge, effluents and heated cooling water are generated. Most countries have stipulated an environmental legislation to provide the framework for an efficient environmental management. As part of the planning activities for a major greenfield copper smelter, the following elaborations are required and were drawn up: The Environmental Impact Assessment, which is the first step of environmental management and mandatory for every new project; The Environmental Monitoring Plan, which describes the monitoring procedures for the main impacts identified and assessed; The Environmental Management Plan, which deals with the minimization of environmental impacts, and the methods of its implementation.
2:55 pm Invited
SMELTER ACID IN THE BROADER MARKET PERSPECTIVE: Michael F. Kitto, Research Manager, Sulphur, British Sulphur Consultants, 31 Mount Pleasant, London WC1X OAD, Great Britain
The production of sulfuric acid at base metals smelters is predominantly an involuntary activity and now comprises approximately 17 % of all-forms sulfur supply in world terms. The majority of elemental sulfur is also produced involuntarily in response to environmental regulations regarding emissions from hydrocarbon processing plants. The paper examines the points of similarity and difference in the sulfur and smelter acid markets, and reviews their interactions. The merchant acid market collapsed in 1993 but has subsequently rallied. The reasons for these developments are considered, and the likelihood of a repeat of 1993 is assessed against the projected growth of overall acid demand and of smelter acid production in the period to the year 2005.
3:25 pm BREAK
3:45 pm
REACTION OF HIGH STRENGTH SULFUR DIOXIDE WITH LIMESTONE AND DOLOMITE AT ELEVATED TEMPERATURE: Ryan Cavanagh, N. A. Warner, School of Chemical Engineering, The University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
Studies relating to the fixation of sulfur by reaction of 3 to 8 mm diameter cylinders of calcined limestone or dolomite with high strength sulfur dioxide in the temperature range 880deg.C to 1020deg.C were undertaken. At relatively low SO2 concentrations gaseous diffusion through the reaction product layer has a marked effect on the rate. As SO2 concentrations are increased up to 100 percent more complex rate controlling mechanisms unfold. By sectioning partially reacted pellets a moving interface was observed but SEM analysis indicated that substantial amounts of unreacted calcium oxide were retained in the reaction product layer. Reaction ceased because of pore plugging for the most reactive limestone at 60-65 % conversion, whereas for dolomite virtually complete sulfation of the calcium was observed. Lower conversions in the less reactive limestones are related to pore structure and internal BET surface area.
4:10 pm
SULFUR FIXATION AT HIGH TEMPERATURE WITHIN THE COPPER SMELTING PROCESS: N A Warner, School of Chemical Engineering, The University of Birmingham, Edgbaston, Birmingham, B152TT, UK
Fundamental studies on the reaction of limestone or dolomite at high temperature are extended into the realm of large scale primary copper smelting. Whereas flue gas desulfurisation in the electric power utility industry is concerned with SO2 concentrations normally less than 0.5 percent, high temperature smelting gases can have SO2 levels approaching 100 percent. The reaction involved is very exothermic so proposals are made in this paper for returning the heat generated in sulfur fixation directly back to the copper smelting process. This integration leads to metal production with lower energy requirements than current technology. The anhydrite reaction product can either be disposed of locally with minimum adverse environmental impact or upgraded to a value-added by-product. It is assumed, of course, that no viable market exists to support sulfuric acid production.
4:35 pm
MINIMIZATION AND CONTROL OF SO2-EMISSIONS BY APPLICATION OF THE CIRCULATING FLUID BED: H. Hirschfelder, E. Stolarski, Lurgi Metallurgie GmbH. Lurgiallee 5, D-60295 Frankfurt am Main, Germany
The Circulating Fluid Bed (CFB) has now surpassed a quarter of a century of
commercial operations. There are more than 80 CFB units operating in the fields
of alumina, coal combustion and gold roasting. The paper describes how SO2 is
captured utilizing the CFB technology in coal combustion and gold roasting
plants. The process, by means of improved mass transfer, enhances the capture
of S02 in the vessel. Depending upon the feed material analyses, additives may
also be required to minimize S02 emissions. An additional benefit of this
process is that it permits the installation of a simpler, less costly off-gas
treatment plant.
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