Evaluating aggregate stability, surface properties and disintegration behaviour of bauxite residue induced by Ca/Na

Land Degrad Dev

Xue, ShengguoKe, WenshunZhu, FengFan, JiarongWang, QiongliLiu, ZhengHartley

Bauxite residue, a typical industrial solid waste which contains a large amount of Na+, is usually physically degraded. Understandings of aggregate formation, which is a critical process in soil development, are essential to facilitate ecological rehabilitation on the disposal areas. However, few studies have investigated the aggregation behaviour and mechanisms of key salt ions (Ca(2+)and Na+) in residue aggregates. Therefore, an integrated method of Le Bissonnais' method, the combined determination method and laser diffraction measurements was applied to evaluate aggregate stability, surface properties and disintegration behaviour of bauxite residue following Ca/Na additions. With increasing Ca(2+)addition, mean weight diameter increased, indicating improved resistance to dispersion. Ca(2+)had a positive effect on flocculation of silt-size microaggregates, while disintegration was induced following Na(+)addition.