Behavior of chromium in the reduction and smelting of high alumina nickel laterite in blast furnace

Abstract

The blast furnace process is developed to produce Fe–Ni–Cr alloy (also called stainless steel master alloys) by smelting nickel laterite in China. However, how to achieve high recovery of chromium from nickel laterite become a challenge due to the limited smelting temperatures in a blast furnace. In this study, the behavior of chromium during the smelting of nickel laterite ore was thermodynamically and experimentally studied. The suitable slag composition was recommended according to the viscosity and flowing temperature of various slags. The smelting experiments indicated that when the basicity was 0.98, the distribution of Cr reaches a high level and the recovery rates of Cr, Fe, and Ni were 92.24%, 98.47%, and 98.59%, respectively. When the MgO content is about 8.37%, the good separation of iron from slag can be observed, while a small amount of metal entrapped in slag with the further increase of MgO content. The results of industrial production in a blast furnace showed that the chromium distribution ratio is a positive correlation with the slag basicity. The Cr2O3 content in slag decreases and the chromium distribution ratio increases with the increasing slag basicity.

Keywords

• Nickel laterite
• Stainless steel master alloys
• Chromium
• Basicity
• MgO
• Blast furnace