Comprehensive Utilization of Red Mud: Current Research Status and a Possible Way Forward for Non-hazardous Treatment

Abstract

Red mud is an alkaline solid waste produced in the process of alumina extraction from bauxite. Presently, more than 3.0 billion tonnes of red mud are estimated to be stockpiled on land with an annual growth rate of approximately 120 million tonnes. The large amount of red mud has become a very real threat to the environment and human health because its high alkalinity presents a potential pollution to water, land and air. This article provides an overview of current research status for the options of comprehensive utilization of red mud and attempts to review their strengths and weaknesses. Ideally red mud is encouraged to be utilized as an industrial by-product for other applications, leading to a zero-discharge situation. On this basis the review recommends the Calcification-Carbonization Method, a promising technology for non-hazardous treatment, to recover the alkali and alumina and meanwhile transform the red mud into a non-hazardous material available for subsequent use.