VALUABLE IRON-CHROMIUM ALLOY STARTING FROM MILL SCALE WASTE USING SELF PROPAGATION TECHNIQUE

The possibility to recycle mill scale waste together with low grade chromite ore, by self propagation metallothermic process, has been studied. Two metallothermic agents have been used aluminum and aluminum-silicon powders. While, lime was used as a fluxing material.

Low-C, high-Cr alloy steel containing 14-17% Cr is successfully obtained by adding Al or Al-Si amount in the charge equals or higher than the stoichiometric ratio. Comparison of the results of both alumino-thermic and alumino-silico-thermic processes, reveals higher metal yield and higher recovery when using alumino-silico-thermic process at lower stoichiometric ratio. On the other hand at higher stoichiometric ratio, using alumino-thermic process results in higher metal yield and higher recovery of alloying elements. However, using Al-Si, as reducing agent, results in higher Si and Al contents in the produced alloy.