Investigation of iron grains growth during solid-phase carbothermic reduction of red mud in the presence of iron metallic particles

Red mud is a hazardous waste obtained from bauxite ore by the Bayer method. It has a high content of iron. In this study, the iron grain growth process during solid-phase carbothermic reduction of red mud in the presence of added iron metallic particles was investigated. Carbonyl iron, cast iron shots and metallurgical mill scale were used as the additives. The influence of amount and fraction of the additives on size of reduced iron grains obtained after reduction roasting of red mud at 1250-1350°C and 60-180 min duration was studied. It is showed that the best effect on size of iron grains has the addition of carbonyl iron and mill scale. In this way, besides red mud, some other iron-containing wastes can be recycled, e.g. mill scale.