Alloy Production from High-Silica Manganese Ore and High-Ash Kazakhstan Coal

Abstract

Engineering principles are outlined for the production of silicon–aluminum–manganese alloy from high-silica manganese ore and high-ash Kazakhstan coal (from the Borly and Saryadyr fields in the Karaganda and Teniz-Korzhunkol coal basins), Tekturmas quartzite, and Shubarkol long-flame coal. By thermodynamic diagram analysis of the four-component Fe–Si–Al–Mn system on the basis of handbook data (and calculated thermodynamic data where no handbook data are available), a mathematical model of the phase structure may be developed. The aluminum–silicon–manganese composition obtained from the Karaganda and Teniz-Korzhunkol coal, in contrast to the aluminum–silicon–manganese alloy from Ekibastuz coal, is shifted on the thermodynamic diagrams toward tetrahedra with relatively large volume. This indicates increased stability and technological predictability. The results of tests in an ore furnace show that aluminum–silicon–manganese alloy of regular composition may be obtained by a continuous slag-free method from high-ash Borly and Saryadyr coal and unconditioned high-silica manganese ore from the Western Kamys field if Shubarkol long-flame coal and Tekturmas quartzite are added to the batch. The alloy composition may be regulated by adding manganese ore to the weighed batch materials. An alloy with the following composition is obtained: 32–53 wt % Si, 15.5–25.0 wt % Al, 12–32 wt % Mn, 8–20 wt % Fe, 0.02–0.05 wt % P, and 0.2–0.5 wt % C. The resulting alloy does not crumble to powder on storage, thanks to the low phosphorus content and high aluminum content (>10%). The phase components of the experimental alloy are determined. The cost of the alloy is low, since it is produced from high-ash tailings coal and unconditioned high-silica manganese ore, with absolutely no coke. The alloy may be used for the reduction and alloying of steel and also as a reducing agent in the production of refined ferromanganese.