Evaluation of the potential use of processed kimberlite to sequester carbon dioxide, EKATI Diamond Mine, Northwest Territories, Canada

In this study, water analyses have determined the waters supplied to the processing plant are dominated by SO4, Mg, and Ca with minor amounts of Na and K and neutral pH. Major dissolved constituents of the discharge water also show high concentrations of SO4, Mg, Ca, Na, and K with a more alkaline pH. Water-rock interaction under atmospheric conditions changes the water quality from input to discharge in the processing plant by an increase in SO4, Mg and Ca. Experiments were designed to duplicate conditions in the processing plant and results showed an increase in these major elements over time approaching concentrations seen in the discharge water. Alkalinity, pH, and chemistry of the experiments all approach results from the processing plant as time increases.; Saturation indices show oversaturation of carbonates (calcite, dolomite, and magnesite) and therefore the potential of these minerals to precipitate in both processing plant samples and experiment samples. Inverse modeling indicates that the change in chemical composition can be explained by the dissolution of Mg-silicates, CO2, and the precipitation of carbonate and silica. An increase in inorganic-C is noted from the kimberlite to the processed kimberlite in the LLCF indicating that carbonates may be precipitating. X-Ray diffraction of processed kimberlite fines and filtered fines from experiments show evidence of carbonate and therefore suggest that the mineral carbonation reaction may be happening spontaneously in the processing plant with the introduction of water. (Abstract shortened by UMI.)...