Extraction, Refining, and Fabrication of Light Metals. Proceedings of the International Symposium on Extraction, Refining and Fabrication of Light Metals, Ottawa, Ontario, August 18–21, 1991 PDF
Preview Extraction, Refining, and Fabrication of Light Metals. Proceedings of the International Symposium on Extraction, Refining and Fabrication of Light Metals, Ottawa, Ontario, August 18–21, 1991
Titles of Related Interest— Ashby ENGINEERING MATERIALS 1 Ashby ENGINEERING MATERIALS 2 Brook IMPACT OF NON-DESTRUCTIVE TESTING Koppel AUTOMATION IN MINING, MINERAL AND METAL PROCESSING 1989 Ruhle METAL-CERAMIC INTERFACES Taya METAL MATRIX COMPOSITES Other CIM Proceedings Published by Pergamon Bergman FERROUS AND NON-FERROUS ALLOY PROCESSES Bickert REDUCTION AND CASTING OF ALUMINUM Chalkley TAILING AND EFFLUENT MANAGEMENT Closset PRODUCTION AND ELECTROLYSIS OF LIGHT METALS Dobby PROCESSING OF COMPLEX ORES Embury HIGH TEMPERATURE OXIDATION AND SULPHIDATION PROCESSES Jaeck PRIMARY AND SECONDARY LEAD PROCESSING Jonas DIRECT ROLLING AND HOT CHARGING OF STRAND CAST BILLETS Kachanlwsky IMPACT OF OXYGEN ON THE PRODUCTIVITY OF NON-FERROUS METALLURGICAL PROCESSES Lalt F. WEINBERG INTERNATIONAL SYMPOSIUM ON SOLIDIFICATION PROCESSING Macmillan QUALITY AND PROCESS CONTROL IN REDUCTION AND CASTING OF ALUMINUM AND OTHER LIGHT METALS Mostaghacl PROCESSING OF CERAMIC AND METAL MATRIX COMPOSITES Plumpton PRODUCTION AND PROCESSING OF FINE PARTICLES Purely FUNDAMENTALS AND APPLICATIONS OF TERNARY DIFFUSION Rigaud ADVANCES IN REFRACTORIES FOR THE METALLURGICAL INDUSTRIES Ruddle ACCELERATED COOLING OF ROLLED STEEL Salter GOLD METALLURGY Thompson COMPUTER SOFTWARE IN CHEMICAL AND EXTRACTIVE METALLURGY TWIgge-Molecey MATERIALS HANDLING IN PYROMETALLURGY IWigge-Molecey PROCESS GAS HANDLING AND CLEANING TVson FRACTURE MECHANICS Wilkinson ADVANCED STRUCTURAL MATERIALS Related Journals (Free sample copies available upon request) ACTA METALLURGICA CANADIAN METALLURGICAL QUARTERLY MATERIALS RESEARCH BULLETIN MINERALS ENGINEERING SCRIPTA METALLURGICA Titles of Related Interest— Ashby ENGINEERING MATERIALS 1 Ashby ENGINEERING MATERIALS 2 Brook IMPACT OF NON-DESTRUCTIVE TESTING Koppel AUTOMATION IN MINING, MINERAL AND METAL PROCESSING 1989 Ruhle METAL-CERAMIC INTERFACES Taya METAL MATRIX COMPOSITES Other CIM Proceedings Published by Pergamon Bergman FERROUS AND NON-FERROUS ALLOY PROCESSES Bickert REDUCTION AND CASTING OF ALUMINUM Chalkley TAILING AND EFFLUENT MANAGEMENT Closset PRODUCTION AND ELECTROLYSIS OF LIGHT METALS Dobby PROCESSING OF COMPLEX ORES Embury HIGH TEMPERATURE OXIDATION AND SULPHIDATION PROCESSES Jaeck PRIMARY AND SECONDARY LEAD PROCESSING Jonas DIRECT ROLLING AND HOT CHARGING OF STRAND CAST BILLETS Kachanlwsky IMPACT OF OXYGEN ON THE PRODUCTIVITY OF NON-FERROUS METALLURGICAL PROCESSES Lalt F. WEINBERG INTERNATIONAL SYMPOSIUM ON SOLIDIFICATION PROCESSING Macmillan QUALITY AND PROCESS CONTROL IN REDUCTION AND CASTING OF ALUMINUM AND OTHER LIGHT METALS Mostaghacl PROCESSING OF CERAMIC AND METAL MATRIX COMPOSITES Plumpton PRODUCTION AND PROCESSING OF FINE PARTICLES Purely FUNDAMENTALS AND APPLICATIONS OF TERNARY DIFFUSION Rigaud ADVANCES IN REFRACTORIES FOR THE METALLURGICAL INDUSTRIES Ruddle ACCELERATED COOLING OF ROLLED STEEL Salter GOLD METALLURGY Thompson COMPUTER SOFTWARE IN CHEMICAL AND EXTRACTIVE METALLURGY TWIgge-Molecey MATERIALS HANDLING IN PYROMETALLURGY IWigge-Molecey PROCESS GAS HANDLING AND CLEANING TVson FRACTURE MECHANICS Wilkinson ADVANCED STRUCTURAL MATERIALS Related Journals (Free sample copies available upon request) ACTA METALLURGICA CANADIAN METALLURGICAL QUARTERLY MATERIALS RESEARCH BULLETIN MINERALS ENGINEERING SCRIPTA METALLURGICA PROCEEDINGS OF THE INTERNATIONAL SYMPOSIUM ON EXTRACTION, REFINING AND FABRICATION OF LIGHT METALS, OTTAWA, ONTARIO, AUGUST 18-21, 1991 Extraction, Refining, and Fabrication of Light Metals Editors Mahi Sahoo CANMET Ottawa, Ontario Peter Pinfold Norsk Hydro Canada Inc. Becancour, Quebec Symposium organized by the Light Metals Section of The Metallurgical Society of CIM 30th ANNUAL CONFERENCE OF METALLURGISTS OF CIM 30e CONFERENCE ANNUELLE DES M E T A L L U R G I E S DE LTCM Pergamon Press New York • Oxford • Beijing • Frankfurt Pergamon Press Offices: U.S.A. Pergamon Press, Inc., Maxwell House, Fairview Park, Elmsford, New York 10523, U.S.A. U.K. Pergamon Press pic, Headington Hill Hall, Oxford 0X3 OBW, England PEOPLE'S REPUBLIC Pergamon Press, 0909 China World Tower, No. 1 Jian OF CHINA Guo Men Wai Avenue, Beijing 1000004, People's Republic of China FEDERAL REPUBLIC Pergamon Press GmbH, Hammerweg 6, OF GERMANY D-6242 Kronberg, Federal Republic of Germany BRAZIL Pergamon Editora Ltda, Rua Ega de Queiros, 346 CEP 04011, Paraiso, Sao Paulo, Brazil AUSTRALIA Pergamon Press Australia Pty Ltd., P.O. Box 544, Potts Point, NSW 2011, Australia JAPAN Pergamon Press, 8th Floor, Matsuoka Central Building, 1-7-1 Nishishinjuku, Shinjuku-ku, Tokyo 160, Japan CANADA Pergamon Press Canada Ltd., Suite 271, 253 College Street, Toronto, Ontario M5T 1R5 Canada Copyright © 1991 Pergamon Press Inc. All rights reserved. No part of this publication may be reproduced in a retrieval system or transmitted in any form or by any means: electronic, electrostatic, magnetic tape, mechanical, photocopying, recording or otherwise, without permission in writing from the publishers. Library of Congress Cataloging in Publication Data ISBN 0-08-041444-3 Printing: 1 2 3 4 5 6 7 8 9 Year: 0 1 2 3 4 5 6 7 8 9 Printed In the United States of America 0™ The paper used in this publication meets the minimum require- ments of American National Standard for Information Sciences- Permanence of Paper for Printed Library Materials, ANSI Z 39.48- 1984 Session Chairmen Aspects of Magnesium Technology M. Sahoo M. Avedesian CANMET Institute of Magnesium Technology Ottawa, Ontario Ste-Foy, Quebec Light Metal Matrix Composites B. Closset J. Masounave Timminco Metals ETS, Universite du Quebec a Montreal Toronto, Ontario Montreal, Quebec Aspects of Light Metals Reduction Technology L. Larouche C. Bickert Canadian Reynolds Metals Co. Ltd. Pechiney Corp. Baie Comeau, Quebec Greenwich, Connecticut, U.S.A. Casting and Solidification of Aluminum Base Alloys P. Pinfold P. Tremblay Norsk Hydro Canada Inc. Arvida R&D Centre, Alcan International Ltd. Becancour, Quebec Jonquiere, Quebec Mathematical Modelling and Computer Simulation R. Guthrie M. Bouchard McGill University Universite du Quebec a Chicoutimi Montreal, Quebec Chicoutimi, Quebec Melting, Alloying and Properties of Light Metals P. Aylen P. Pinfold Alumax Inc. Norsk Hydro Canada Inc. Montreal, Quebec Becancour, Quebec v Foreword The Light Metals Section of the Metallurgical Society of CIM has been organizing international symposia for the last three years on advances in different aspects of light metals technology during the Annual Conference of Metallurgists. This year in conjunction with the 30th Annual Conference of Metallurgists of CIM, the Light Metals Section is proud to present its Fourth International Symposium on "Extraction, Refin- ing and Fabrication of Light Metals". World-class scientists and engineers from more than six countries are presenting over thirty papers on topics such as magnesium casting technology, metal matrix composites, mathematical modelling, solidification, and reduction of light metals. In view of Canada's recent emergence as an important magnesium producer, a separate session will be held to focus on the recent advances in magnesium technology. Metal matrix composites are an important class of the advanced industrial materials and signifi- cant advances have been achieved recently on the fabrication and characterization of their micro- structures and mechanical properties. The session on light metal matrix composites comprises papers on some of these recent developments. As the Symposium chairpeople, we wish to express our sincere thanks to all the authors for preparing their manuscripts in time for publication, and for presenting their papers at the Symposium. One of us (M.S.) would like to acknowledge the assistance provided by Messrs. Peter Newcombe and Bob Emmett in taking care of the preliminary planning and correspondence for the Symposium announcements. Mr. Newcombe, in particular spent considerable time compiling the addresses and preparing the technical program for the sessions. The moral support of the management of the Metals Technology Laboratories of CANMET is also gratefully acknowledged. August 1991 Mahi Sahoo Peter Pinfold Editors vii 3 Production and applications of ultra high purity magnesium S.G. Hibbins, F.C. Dimayuga Timminco Metals, A Division of Timminco Limited, Haley, Ontario, Canada INTRODUCTION 1 Timminco Metals Haley, Ontario facility has produced magnesium metal and alloys since 1942. Under the guidance of Dr. L.N. Pidgeon, this plant became the first commercialized application of the classical Pidgeon Process for producing magnesium metal (1,2,3,4). Today, this 800 acre facility is the recognized leader in the production of the world's highest purity magnesium metal and alloys. Timminco has been responsible for significant advancements in the production and application of light and reactive metals. The original thermal magnesium process has been adapted to the production of calcium and strontium metals. Research and development has led to the introduction of such products as CAL-AL and MAGCAL for use by the lead industry, a variety of strontium products including a 90% Sr - 10% Al alloy for use by the aluminum foundry industry and various granular and particulate magnesium and calcium products. Timminco has made significant process improvements over the years to increase automation and efficiency of the silicothermic magnesium process and also to refine the process to consolidate its status as producer of the highest purity magnesium commercially available. Today, Timminco Metals operates three production facilities which are shown in Figure 1. The Haley plant remains the primary source of magnesium metal and alloys, ingots, extrusions, granules and particulates. The Westmeath plant, which was commissioned in 1987, is the source of strontium and calcium metal and special alloys. The Beauharnois facility continues to supply 85% and 75% ferrosilicon to Haley and a limited number of customers in the steel industry. The unique nature of the metallothermic process facilities enables Timminco to maintain a high degree of operating flexibility with a variety of products being manufactured at either the Haley or Westmeath plants, as circumstances require. As a major part of the company's efforts to continuously improve the quality and delivery of its products, Timminco has implemented a comprehensive Quality Assurance Program which is designed to meet and in some cases, exceed the requirements of the Canadian Standard Z299.3 (5). As a result, Timminco's Westmeath operations have been given a Ql Preferred Quality Supplier Award by the Ford Motor Company. 4 EXTRACTION, REFINING AND FABRICATION OF LIGHT METALS In recent years, Timminco has reaffirmed its commitment to research and development, especially towards new process and product development. In 1988, with the transfer of specialty metals production to the Westmeath plant, investments have been made at the 7500 square foot Haley Research facility, with the installation of 3 new experimental melting furnaces and additional small-scale vacuum furnace capacity. Timminco also has an active out of house R & D programme, which has included research at several universities, the Canada Centre for Mineral and Energy Technology (CANMET) and the Institute of Magnesium Technology (IMT). TIMMINCO METALS HALEY WESTMEATH BEAUHARNOIS Integrated R&D Magnesiuiim Pilot Plant SmBeillt er magnesium new products Sr + Ca ferrosilicon metal S alloys; + processes products, ingots, special alloys extrusions, granules Figure 1 - Timminco Metals Facilities. THE SILICOTHERMIC MAGNESIUM PROCESS Process Description In the production of magnesium by the Pidgeon silicothermic process (Figure 2), high purity dolomite, quarried from an on-site open pit, is crushed, classified and calcined. The burned dolomite is subsequently mixed with a controlled amount of ferrosilicon obtained from Timminco^ Beauharnois, Quebec ferroalloy plant. The mixture is briquetted and charged to high-alloy steel retorts contained in gas-fired furnaces. Reduction is carried out under vacuum at about 1200°C according to the following chemical reaction: 2MgO CaO + Si = 2Mg + 2CaO Si0 (1) 2 During this reaction, metallic magnesium is vaporized and transported to a controlled temperature condenser where sublimation takes place. After a specified period of time, the vacuum is broken and the condensed "crown" of magnesium metal and the dicalcium silicate slag are discharged from the retort. The metallic crowns are subsequently processed to produce a variety of pure metal and alloy products including ingots, billets, sacrificial anodes, extrusions and granules. EXTRACTION, REFINING AND FABRICATION OF LIGHT METALS 5 Reductant Briquetting Slag Melt & Alloy Ingots & Extrusions Package Cut & Size & Ship Granulate Chemical Laboratory On-Line f Computer Data Base Figure 2 - Timminco s Metallothermic Vacuum Reduction Process. Over the years, substantial progress has been made in automating the Pidgeon process. Froats (4) outlined the advances which have been implemented to improve the tooling for charging and discharging the multiplicity of small units characteristic of the process. Automated equipment was developed to distribute a predetermined quantity of briquette charge in the horizontal retorts prior to the vacuum reduction cycle. The technology to remove hot spent residue by a vacuum pneumatic system was also developed. By these developments, the laborious manual tasks of charging briquettes and discharging residue were eliminated. Since 1980, further improvements have been implemented in the process, the most significant of these being: upgrading of plant milling, mixing and briquetting equipment, including improved, automatic control of raw material batch weights. conversion of electric retort furnace capacity to gas- fired furnaces incorporating energy-efficient regenerative burner technology. implementation of statistical process control (SPC) in all phases of plant operation, as part of a comprehensive quality assurance program (5). automation and streamlining of several downstream operations, e.g., metal crown handling, granulating and extrusion. Metallurgical Efficiency A significant body of knowledge has been developed at Timminco on the metallurgy of the Pidgeon process (1,2,3,4). Operating efficiency is dependent on such variables as temperature, vacuum, cycle time, type of reductant, raw material sizing, briquette density, retort alloy composition and dimensions. 6 EXTRACTION, REFINING AND FABRICATION OF LIGHT METALS The roost significant factor affecting operating efficiency is the relationship between magnesium reduction recovery and ferrosilicon use. According to reaction (1), the stoichiometric requirement is 0.577 kg Si per kg of Mg contained in the retort charge. In practice, an excess of the stoichiometric amount is necessary to obtain high Mg recovery. The excess amount must be determined empirically, as no adequate theoretical prediction based on the Fe-Si phase diagram can explain the optimum operating region. Plant operations can be run equally well using either 75% or 85% ferrosilicon, although at present, 85% ferrosilicon is preferred due to slightly higher operating productivity. The optimum operating condition is based on a combination of ferrosilicon usage, magnesium recovery, ferrosilicon price, production rate and other operating factors. HIGH PURITY MAGNESIUM Overview of Applications Magnesium has a diversity of applications, as Figure 3 shows. The main applications can be grouped as aluminum alloying, chemical and structural uses. As shown, 52% of world magnesium shipments in 1990 were used in aluminum alloying. Chemical applications, including nodular iron, steel desulphurization, metal reduction, sacrificial anodes and Grignard reagents, accounted for about 27% of magnesium consumption. Structural applications (die and gravity casting, wrought products) were about 18% of world magnesium consumption in 1990. Chemical applications account for most of the consumption of higher purity magnesium. The development of high purity magnesium alloys has alleviated many of the concerns related to corrosion of magnesium in structural applications. The most significant growth potential for magnesium consumption is expected to be in magnesium casting alloys. Aluminium 52% Other 3% Nodular Iron Structural Desulfurization 18% 11% Chemical 10% Total shipments 1990; 252.000 mt Figure 3 - Primary Magnesium Shipment by Market Segment, 1990. (Source IMA).
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