Using red mud for flue gas storage and treatment: A green solution for the alumina industry

Abstract

The production of alumina by the Bayer process invariably generates two types of hazardous waste: red mud and greenhouse gas emissions. Red mud is a voluminous solid residue consisting primarily of 30÷60% Fe₂O₃, 10÷20% Al₂O₃, 3÷50% SiO₂, 2÷10% Na₂O, 2÷8% CaO, and approximately 10% TiO₂. Due to its high alkalinity (pH 10÷13), red mud is not only difficult to manage but also poses potential risks of soil, water, and ecosystem contamination if improperly handled. In parallel, the combustion of fossil fuels during alumina production releases greenhouse gases along with other pollutants such as CO, CO₂, SO₂, NOₓ, and fine particulate matter, thereby contributing to climate change and deteriorating air quality. Nevertheless, the strong alkalinity of red mud makes it a promising material for adsorption and neutralization of acidic wastes, particularly flue gases from fossil fuel–fired power plants. Thus, utilizing red mud for greenhouse gas capture and treatment offers dual environmental benefits: mitigating gaseous emissions while providing a sustainable waste management strategy for the alumina industry. This paper reviews international research and practical applications of red mud for greenhouse gas storage and treatment. Building on these findings, it proposes technological directions for the simultaneous management of red mud and gaseous emissions generated during alumina production in Vietnam. Such an integrated approach is expected to enhance environmental performance while supporting the sustainable development of Vietnam’s bauxite and alumina industry.