Experimental Investigation on Reduction of Cast Iron from Bayer Red Mud and Laterite Nickel

Abstract

In this paper, a process of extracting cast iron from red mud and laterite nickel has been proposed. Red mud, lateritic nickel, CaO and coke were heated together inside an electric arc furnace so as to obtain a cast iron alloy. The experiments indicated that recovery rates of the cast iron alloy were from 70 to 89% when the coke content increases from 20 to 35%. The microstructure of the alloys depends mainly upon the coke content. The metallographic structure features white iron when addition of coke was below 25%. Free graphite flakes appeared when the coke content was 25%, where the microstructure may feature cementite and stripe-shaped graphite. If the coke content gets to 30% or more, the microstructure is characterised by grey iron. The test work shows that the impact energy increases and hardness decreases of the alloys with increasing coke content and the microstructures change accordingly from white iron to grey cast iron. In conclusion, this process is a potential technology for reduction of cast iron alloys from red mud and lateritic nickel.