Production of Aluminum–Chromium–Silicon Alloy from Unconditioned Materials

Abstract

At Abishev Chemical and Metallurgical Institute, highly effective new alloys have been developed on the basis of resource-saving technology. The alloys may be produced from natural and industrial materials such as coal waste and chromium-ore fines. The result is a single-stage, slag-free, and waste-free technology with the maximum utilization of all the useful batch components. As reserves of rich ores are exhausted, alternatives must be sought. The use of leaner and unconditioned ores calls for new processing methods. Such technologies must make the best possible use of the raw materials and production wastes, within the limits of economic feasibility. In many cases, this complex problem is associated with the development of complex processing methods capable of utilizing all the useful components in the raw materials within a single production cycle. In the present work, the goal is to find means of more efficiently utilizing unconditioned chromium ore. In the electrosmelting of aluminum–chromium–silicon alloy, the traditional reducing agent is coke, which is expensive. Our proposal is to use inexpensive high-ash Borly coal. The ash in this coal consists mainly of silica and aluminum and provides an additional source of silicon and aluminum for the alloy. The proposed technology is simple and makes effective use of unconditioned chromium ore, which provides not only chromium but also the silicon and aluminum present in the ash. By complete reduction of all the oxides in the batch, this technology yields aluminum–chromium–silicon alloy with the following approximate composition: 39–43% Cr, 23–27% Si, and 7–10% Al. The extraction of the basic batch components in the alloy is as follows: 82–85% Cr, 68–70% Si, and 59–60% Al. Experimental data are presented for the production of aluminum–chromium–silicon alloy from high-ash Borly coal and chromium-ore fines from Don enrichment facility. Furnace operation is described in the case of deficient, excess, and correct quantities of reducing agent. Methods of eliminating furnace disruption are outlined.