SOLIDIFICATION STABILIZATION OF HAZARDOUS ARSENIC-CONTAINING WASTE FROM A COPPER REFINING PROCESS

An industrial waste, originating from a metallurgical process in which copper is refined and containing large amounts of arsenic (42 wt%), was studied. A suitable treatment method, solidification/stabilisation (S/S), allowing a reduction of the leachability of arsenic from the waste was studied and optimised by measurement of the influence of all additives (waste acid, blast-furnance slag, slaked lime, cement) used in the process. The S/S process could thus be simplified considerably. The addition of lime to the waste was the most important factor in reducing the arsenic concentration in the leachate by formation of a hardly soluble calcium-arsenic compound. To reduce the arsenic concentration in the leachate even further, by formation of other insoluble compounds, the addition of aluminium and barium salts was investigated.