Preparation of Brown Iron Oxide from Secondary Raw Material.

The preparation of inorganic brown pigment from red mud is investigated. The results of the phase and chemical analyses of raw material and the product are given. A flow diagram is proposed and the parameters of the pigment production are recommended. This approach has provided a pigment of pure color with the opacity of 8 to 10 g m-2 from red mud (up to 80%) without additives and the reduction of Fe(III) into Fe(II) using sulfide sulfur. [ABSTRACT FROM AUTHOR]