Sponsored by: LMD Aluminum Committee
Program Organizer: C.G. Hendriks, Kaiser Aluminum and Chemical Corp., 9131 Interline Drive, Baton Rouge, LA 70809
Thursday, AM Room: A6
February 8, 1996 Location: Anaheim Convention Center
Session Chairman: Gerald Kelton, Krebbs Engineers, 1205 Chrysler Dr., Menol Park, CA 95025-1178
THE FUTURE OF ALUMINA/BAUXITE MINING IN GUINEA: New Approaches Toward Growth and Competitiveness: Siafa Coulibaly, Department Inspector Ministry of Mines and Geology, PO Box 295, Conakry, GUINEA
Guinea is one of the richest countries in Africa in view of its bauxite mining and energy potential. It has nearly one-third of the world's bauxite reserves and it is the second world producer of this mineral, coming after Australia. The mining sector plays a key role in the Guinea economy. The state will continue to depend highly on this sector fiscal revenue and foreign exchange for the coming years at least. Guinea is currently facing serious economic problems. Some of these problems are the result of a hostile external environment over which it has little or no influence, let alone control. It is therefore a prime importance that government should adopt effective policies with regard to management and making viable regulation to govern the alumina/bauxite industry, as well as acquire strong capacity to implement them. Since the market of these commodities remains extremely depressed, the Guinea alumina/bauxite industry is subject to decline. In order to arrest this situation, the country wants to embark on a path toward diversifying its mineral industry and supporting efforts for global economic liberalization, good communication, transport, energy and agriculture. This paper will survey the basic parameters such as resources and competitiveness, Guinea's prospective in terms of efficiency technology equipment rehabilitation, environmental consideration. The article will emphasize on Guinea position in the market, the problem of pursing the production tools, the matters of competitiveness related to quality of bauxite, production cost reduction, fiscal regime, market arrangements, increase production capacities by opening new bauxite mines.
OPERATION OF A 24 MTPD SOLID-LIQUID CALCINER (SLC) FOR LIQUOR PURIFICATION IN A BAYER PLANT: Jens Fenger, F.L. Smidth & Co. A/S, Research & Development Department, Vigerslev Alle 77, DK 2500 Valby Copenhagen, Denmark; Joergen IIkjaer, FLS Minerals, Alumina & Bauxite Technology, Liam Fleming, Aughinish Alumina Limited; Jose Pulpeiro, Alumina Espanols, S.A.; Andy Carruthers, Alcan International Limited
FLS Minerals, in association with Aughinish Alumina, Alumina Espanola, and Alcan International, has developed a liquor purification system for alumina refineries. Laboratory work has been carried out to characterize the behavior of different feed slurries, and several tests have been carried out on a 24 MTPD pilot plant at the FLS Research Center in Denmark. This paper reports the results of the laboratory work and the operation of the pilot unit. Examples of start-up and shut-down sequences are described.
USING OF PETROLEUM COKE DUST AS A PARTIAL SUBSTITUTE FOR NATURAL GAS AND FUEL OIL IN THE ALUMINA TRIHYDRATE CALCINATION PROCESS: B. Desgrosseilliers, J. Perron, Alcan International Ltd., PO Box 1250, 1955 Blvd. Mellon, Jonquiere (Qc.), Canada G7S 4K8; Pierre Laurier, Odette Menard, Jocelyn Martin, Alcan Smelters & Chemicals Ltd., Jonquiere (Qc.), Canada G7S 4L2
In the Saguenay region, Alcan operates two rotary kilns for calcining petroleum coke in order to provide the pre-bake anode and Soderberg paste production plants with calcined coke. The annual production is about 220,000 metric tons. For several years, under-calcined dust has been escaping from the kilns with the hot gases; this undesirable product amounts to about 16,000 mt per year. A maximum of 6,000 mt of dust has been recycled in the fabrication process. In the search for different recycling or sale possibilities for the remaining 10,000 mt, there arose the possibility of using this coke dust as a source of calorific energy in other processes and more particularly in the calcination of alumina trihydrate. A combustion feasibility study and a plant trial demonstrated the benefit of burning this dust in two calcination units with a capacity of 60 mt per hour. In effect, an appreciable economy of natural gas or fuel oil as well as increased energy efficiency (gain of 6%) was observed in the calcination units. Moreover, the effect on the quality of the metallurgical alumina is negligible. These results may be explained in part by the use of solid fuel for which the combustion time is of the order of 1000 times greater than that of natural gas. The combustion zones are thus elongated, favoring the transfer of heat towards the solid alumina during calcination.
APPLICATION OF HYDROCYCLONE IN BAYER CIRCUIT: Gerald P. Kelton, Krebs Engineers, 1205 Crysler Drive, Menlo Park, CA 94025
Due to its operational simplicity, effectiveness, low space requirement and maintenance cost, hydrocyclones of different sizes and material of construction are progressively finding more and more application in Bayer circuit for producing alumina from bauxite. In alumina refining process, hydrocyclones are most effectively used in the areas like closed circuit grinding, sand separation, sand washing, removal of residual solid from spent liquor and second stage filtrate to enhance plant productivity and classification of hydrate particles for product and seed granulometry control. The paper described the main features of the hydrocyclones installed at different units, its operational experience and performance achieved during the last nine years of plant operation, paper also covers the role of spent liquor solid separation cyclones a project under implementation, for augmenting productivity and plant capacity.
10:10 am BREAK
IMPROVED FLOW CHARACTERISTICS OF BAUXITE BY TREATMENT WITH BAUXITE HANDLING CHARACTERISTIC MODIFIER: Carlos Cardounel, Reynolds Metals Company, PO Box 9911, Corpus Christi, TX 78469; Kevin O'Brien, NALCO Chemical Co., 13333 Blanco Rd.,Suite 316, San Antonio, TX 78216
Sherwin Plant bauxite handling facilities are capable of processing relatively free flowing dry bauxites. The processing of wet bauxite through these facilities was challenging and required the use of back-hoes and bulldozers. The use of a bauxite handling characteristic modifier to enhance flow properties of wet bauxite was investigated in the laboratory and subsequently tested in the plant. A significant improvement in flow characteristics was achieved. The bauxite became free flowing, eliminating the need for back-hoes and bulldozers to reclaim the bauxite. This paper relates how laboratory testing led to successful plant application of the bauxite handling characteristic modifier.
OPTION OF BAYER DIGESTION TECHNOLOGY AND EQUIPMENT FOR CHINESE BAUXITE: Ma Chao-jian, Tian Xin-jiu, Shenyang Aluminum and Magnesium Engineering and Research Institute, 184 Hepingbei Street, Shenyang LN 110001, Liaoning, China
China is rich in bauxite with a proven reserve of more than two billion tones, which almost is the diaspore with complex and various minerals. To treat this kind of ore the Bayer digestion possesses it's own characteristic because of the high temperature and caustic concentration. Based on the behavior of silicon and titanium minerals digested in the lab and plant, the digestion technology and equipment for Chinese bauxite be discussed; and based on the Chinese construction condition, the economic comparison of several typical and industrial digestion devices be estimated in the paper. As a conclusion, a proper digestion technology and device for Chinese bauxite be proposed.
ALUMINA PRODUCTION IN RUSSIA: AN OVERVIEW: Dr. V. S. Smirnov, Chief Consultant, Alumina , AO VAMI, 86, Sredni pr, St. Petersburg, 199026, Russia
Alumina production in Russia: heritage of the system relying on its internal resources. History in brief of establishing Russia's alumina plants: a pre-war period - constructing new facilities, commissioning new capabilities during the second world war returning old capacities into service after the war and expansion of the plants built in the following years. Introduction of new local raw materials and construction of major processing facilities. List of Russia's alumina plants after a collapse of the Soviet Union and formation of the CIS. Data covering the plants including production capacities, locations, power supply, a source and quality of a raw material processed. Schematic flowsheets, size of major types of equipment. Difference of bauxite processing parameters and of the process employed between Russia's plants and Western plants. Innovations introduced during the plants' history. Switch to a market economy and new challenges of survival in a competitive world. The main ways of cutting production costs at the plants. Forecast for an alumina production in Russia.
TECHNOLOGICAL FEATURES OF THE PROCESSING OF THE ALUMOSILICATE RAW MATERIAL WITH POTASSIUM'S HIGH CONTAIN: V. A. Lipin, N. N. Tikhonov, VAMI, 86 Sredny Dr. LTG, St. Petersburg 199025 Russia
The deposits of alumosilicate raw material with high portion of potassium
alkali are revealed in Russia, China, Pakistan, Northern Korea, Iran, Venezuela
and other. These ores are studied with the purpose of the industrial processing
by the sintering method for production of alumina, cement, potassium compounds,
some rare elements. This process has been in use at the Russian alumina plants.
The equations of the dependence of technological indexes from chemical
composition of processing area were made on the basis of numerous experimental
data using the original programs. This enabled us to choose the most effective
conditions during our research on nepheline raw materials in the main
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