Utilization of Bauxite Slag for the Purification of Industrial Wastewaters

Production of the coagulant using bauxite waste (red mud and waste base) as raw material and the results of the testing of this new product in laboratory and field condition (pilot plant, full scale plant) were presented. Results showed that red mud could be used as a low-coast solution for heavy metals removal from its own waste base and other industrial wastewaters after partial dissolution with diluted sulphuric acid and neutralization with the waste base. This coagulant is especially suitable for the treatment of the wastewaters generated from the pressure washing of boats in the marinas. The coagulant produced from the red mud has few advantages compared to the commercial Fe and Al salts:(1) Coagulation/flocculation process could be done in one step without coagulant aid or any other chemical addition.(2) pH measurement during the purification could be avoided due to the negligible pH variations of the treated solution.(3) Allow one step removal of the cationic and anionic species from the wastewater.(4) One dose of coagulant is sufficient for five repeated treatment cycles.(5) Negligible leaching of heavy metals from the waste mud under normal environmentalconditions.(6) Safe for the transport, storage and handling.