Neutralization of High Ferric Iron Acid Mine Drainage

摘要

Lime, limestone, and soda ash were studied as neutralizing agents for treatment of a ferric iron acid mine drainage water. Both continuous flow and batch tests were used to determine the effectiveness of each of these neutralizing agents in reaction with acid mine water. Comparisons made between the three neutralizing agents include: chemical costs, reaction efficiencies, effluent water qualities, sludge settling rates, sludge volumes, and percent solids of sludges. All three neutralizing agents were capable of treating acid mine drainage. Lime costs were half that of limestone for treating the same acid mine drainage because of the low utilization of limestone. However, the characteristics of the limestone sludge were superior to those of lime and soda ash sludges. The cost for soda ash treatment was excessive. Further research on improving limestone utilization is under way. No difference in reaction efficiency were found in dry feeding or slurry feeding the neutralizing agents. Aeration during and/or after the limestone reaction merely increased the effluent pH but failed to increase limestone useage efficiency or improve effluent quality. (Author)