Chemical and Geotechnical Properties of Red Mud at Liulin, China

Disposal and storage of red mud are essential concerns due to its huge volume and high alkalinity, and understanding its properties is the basis to mitigate the risk. In this study, the chemical and geotechnical properties of red mud at Liulin, Shanxi Province, China were comprehensively investigated. The major mineral compositions were katoite, andradite, hematite, anorthite, periclase, sodalite, paravauxite, and magnesite. SiO2 (20.76%), Al2O3 (20.40%), CaO (17.56%), Na2O (17.33%), CO3 (12.87%), Fe2O3 (6.44%) accounted for 95.36% of red mud. The content of Fe2O3 (6.44%) was substantially lower than that in other areas. Diameter of the red mud particles was in the range of 0.008-300 mu m and 97% of the particles was silt and clay. The specific gravity, density, water content, hydraulic conductivity of the red mud were 2.77, 1.70 g/cm(3), 50.15% and 4.5 x 10(-6) cm/s, respectively. The liquid limit, plastic limit and plasticity index were 64, 42, and 22, respectively. The ranges of friction angle and cohesion were 28.7-33.1 degrees and 7.8-35 kPa, respectively, and both of them decreased as water content increasing from 50% to 65%. The results in this study are very useful for the design and operation of red mud stack and utilization of red mud in China.