The influence of weathering on the reduction of llmenite with carbon
- PDF / 3,528,609 Bytes
- 11 Pages / 614.28 x 794.28 pts Page_size
- 96 Downloads / 147 Views
I.
INTRODUCTION
THE mineral
ilmenite (FeTiO3) is found in nature in an extensive series of compounds, solid solutions, and alteration products. A major proportion of the mined ilmenite is the raw material for the production of rutile, which is used to produce pigment grade TiO2 and titanium metal. Many methods have been proposed tl,2j for upgrading ilmenite to a rutile substitute by selective removal of iron. These include smelting, direct acid leaching, selective chlorination, and reduction processes. The solid-state reduction of ilmenite, in which ilmenite is reduced to metallic iron and rutile which are subsequently separated by leaching, has received a great deal of attention in the recent past. The reduction of synthetic as well as naturally occurring ilmenite has been studied extensively, t1-41 The reaction sequence, tS-11j the kinetics of reduction, t12-2~ and the role of preoxidation t2~ have also been studied. In the reduction with carbon, it has been concluded t13,15~that the reaction proceeds through carbon monoxide as a gaseous intermediate at temperatures above 1000 ~ The majority of published work, however, is restricted to temperatures of 1200 ~ and above. It has also been shown [19] that it is difficult to nucleate iron in the reduction of synthetic ilmenite with carbon, which can be overcome by the addition of a catalyst such as ferric chloride. The influence of weathering of the ore on the rate of reduction and morphology of the iron, however, has not been examined. The present investigation is con-
SURESH K. GUPTA, formerly with the Imperial College, London, is National Research Fellow, G.K. Williams Laboratory for Extractive Metallurgy Research, Department of Chemical Engineering, Melbourne University, Parkville, Victoria 3052, Australia. V. RAJAKUMAR, formerly with the Imperial College, London, is Principal Research Scientist, CSIRO, Division of Mineral and Process Engineering, Clayton, Victoria 3168, Australia. PAUL GRIEVESON, Professor of Applied Metallurgy, is with the Department of Materials, Imperial College of Science and Technology, London SW7 2BP, United Kingdom. Manuscript submitted June 9, 1988. METALLURGICAL TRANSACTIONS B
cerned with the reduction of three ilmenite concentrates: Westralian Sands Limited (WSL), Western Mineral Sands (WMS), and Florida, which differ significantly in the degree of weathering. Western Mineral Sands concentrate was the least and Florida concentrate was the most weathered, while WSL concentrate exhibited an intermediate degree of weathering. The isothermal reduction of these concentrates with coal at 1000 ~ to 1100 ~ was investigated. If satisfactory separation of the iron could be obtained following reduction at these temperatures, significant savings in energy and costs would be achieved. Synthetic ilmenite (chemically pure FeTiO3) was also reduced with coal in order fo obtain results for comparison with those for the concentrates. The role of ferric chloride additions in the reduction of the concentrates with coal is examined in detail with a view
Data Loading...
