A Detailed Geotechnical Investigation on Red Mud and Chemical Analysis of Its Leachate

Bauxite residue or red mud is the iron-oxide rich waste produced when bauxite ore is processed by the Bayer’s process to extract aluminum. Red mud characteristics and production depend on origin, quality and composition of bauxite. Storage and disposal of red mud is the biggest problem faced by the aluminum industries. Red mud residue is associated with being chemically basic, high in heavy metals and low level of naturally occurring radioactive materials. The objective of this study was to characterize red mud which is collected from Hindalco, Belgaum, on the basis of traditional geotechnical methods that may contribute to the behavior of the material and to analyze the chemical constituents of its leachate which helps to understand the leachate characteristics. The characterization of the material included index properties like moisture content, specific gravity, grain size distribution, liquid limit, plastic limit and their indices, engineering properties like shear strength by cohesion intercept and angle of internal friction, compaction characteristics by OMC and MDD and chemical properties by SEM, XRD and TCLP. The findings, in terms of leachate characteristics, showed that red mud has undergone reactions during the leaching process giving leachate with sodium, silica and calcium in highest concentration. Red mud shows acceptable characteristics for potential reuse as a civil engineering material.