Neutralization of Red Mud Using Mine Water

Abstract

Red mud is the byproduct of commonly used Bayer process for extraction of alumina from bauxite ore. Globally, there are approximately 70 million tones of red mud being produced every year. Highly alkaline red mud, usually pH ranges from 10.5−13 and high caustic causes environmental disposal problem and their reuse. The results show that pH of red mud decreased to standard environmental level using mines water. Sodium ions dominated among the soluble cations, but the sodium ion concentration decreased with increasing duration of storage time due to leaching which causes water pollution. The acid neutralizing capacity of red mud obtained from this study was about 5.5 mol/kg. Mine water neutralization process led to many benefits, including conservation of fresh water due to less use of fresh water at the refinery, increasing settling rates at the red mud pond, reduces the pH, easy to handle and reduces the cost of waste management. The neutralized red mud can be used for other socio-economical and environmental benefits.