Treatment of mine tailings using ALFA® technology

To evaluate the success of the ALFA technology to stabilise and solidify the acid-producing tailings by means of ettringite formation, a tailings sample from a mine in the province of Quebec, Canada, was subjected to treatment and subsequent evaluation. The tailings sample was initially subjected to physical and chemical analysis and the optimised condition for the formation and precipitation of ettringite within the sample was established via X-ray diffraction analysis. To establish whether the pozzolanic reactions has occurred in the treated samples and monitor the growth of ettringite in the specimens under investigation, samples were cured for 3, 28, 90, 360, and 660 days and were analysed for their mineralogical constituents. The treated samples with the aluminium, lime and fly ash (ALFA) technology were subjected to different leaching tests. The leachants were simulated groundwater with a pH of 5·5; acid rain with a pH of 4·5, which contained sulphuric acid; a sulphuric acid solution with a pH of 2·...