SOLIDIFICATION FOR THE HEAVY METAL MINE TAILING BY USING PORTLAND AND MSG(MICRO SILICA GROUTING) CEMENTS

Heavy metal mine tailing was treated using solidification process with Portland and MSG (micro silica grouting) cements as solidification solidifiers. Single axis compressible strengths of solidified matrices with tailing were measured and their heavy metal extraction ratios were calculated to investigate the solidification efficiency of solidified matrices. The single axis compressible strengths of solidified matrices ranged 1 to 2 kgf/mm², which were higher than Korean limit of compressible strength for the inside wall of the isolated landfill facility (0.21 kgf/mm²). The heavy metal extractions from the intact tailing and the powdered solidified matrix with tailing were measured in the leaching test. As concentration in the extraction solution of the solidified matrix decreased to lower than one fifth of intact tailing extraction concentration. Pb extraction concentration of the solidified matrix also decreased to lower than one fourth of intact tailing extraction concentration. The experiment of heavy metal extraction for the solidified matrices in various pH conditions of immerged solution was performed. With pH 1 and 13 of solution, only Pb concentration of immerged solution was over Korean Groundwater Tolerance Limit (KGTL, Pb: 0.1 mg/L), however in pH 3~11 of the solution, heavy metal concentrations maintained much lower than KGTL. When the solidified matrix was immerged into very acidic or basic solution (pH 1 and 13), pH of solution quickly changed to 9~10 because of the buffering effect of the solidified matrix. Results of these experiments showed that the solidification process by using Portland and MSG cements is successful control the heavy metal contaminated mine tailing left to ruin waste.