Leaching Characterization of Red Mud.

Red mud produced in the Bayer process is usually disposed of as a slurry. In spite of the great amount of it, economically worthwhile utilization has not yet been realized. The main purpose of this study is to recover valuable components, especially titanium in red mud. The difficulty of applying flotation to red mud for recovering titanium, iron and aluminum compounds is based on the fact that red mud is composed of very fine particles in which the individual components become associated with the others prevailing in the slurry. Therefore, the leaching of valuable components from red mud was investigated by means of a few inorganic acids such as hydrochloric acid, sulfuric acid, and nitric acid as a function of leaching time, acid concentrations, and solution temperatures. Leaching of Si and Al in red mud is little affected by the kinds of acids and the solution temperatures. The extraction of both elements amounts in equilibrium to 70 percentages after about ten minutes. On the other hand, leaching of Fe and Ti in red mud is much affected by both of the leaching temperatures and the acid concentrations, especially by hydrochloric acid concentrations.