Stabilisation de Résidus Acides Miniers par des Résidus Alcalins D'usines de Pâtes et Papiers Neutralization of Acid Mine Tailings by Addition of Alkaline Sludges from Pulp and Paper Industry

Mine tailings generating acidic effluents were neutralized by alkaline sludges produced in pulp and paper mill operations. Depending on the proportion of sludge added, the resulting pH values increased from 3.96 to between 10.9 and 12.4. The sludge incorporation also increased the buffer capacity of the mining residues. Leaching studies conducted in laboratory columns for a period of about 25 weeks showed the efficacy of sludge incorporation with acid mine tailings. The basic sludges were well mixed with the mining wastes in varying proportions (33, 50, 67, and 75% v/v). It was observed that this incorporation improved the leachate quality considerably. Therefore the leachate pH of the mixtures remained stable between 11.5 and 12.5 compared to a pH of 3.7 for the leachate coming out of the blank column. The metal concentration of Cu, Zn and Mn in the leachate was reduced by 80 to 100 %. In the case of Pb, however, the reduction was not as significant. On the other hand, microbiological tests revealed that...