Recovery of Iron and Titanium in Red Mud with Secondary Aluminum Dross Followed by Manufacturing Glass Ceramics

Red mud is a waste discharged from alumina production by Bayer process. It contains iron and titanium resources. Secondary aluminum dross (SAD) is a waste discharged from aluminum smelting and processing. It contains hazardous reactive aluminum nitride (AlN). In this work, iron and titanium in red mud were reduced by AlN in SAD by pyrometallurgy, and slag was manufactured into glass ceramics. Recovery rates of iron and titanium were 97% and 75%, when addition amount of red mud was double of SAD. The reduced iron and titanium were in form of metal iron and titanium nitride (TiN). Reduction process consisted of two steps: AlN, iron and titanium entered aluminosilicate network of melt; AlN reduced iron and titanium. Density, water absorption and microhardness of the glass ceramics were 3.10 g cm−3, 0.03% and 1195 HV. Utilizing 1 ton of SAD to replace carbon for iron reduction could reduce carbon emissions by 407 kg. In addition, co-disposing 400 kg red mud and 200 kg SAD could gain profit of 293 dollars. This work realized the total recycling of both red mud and SAD.