Mineral Reaction Kinetics During Water–Rock Interactions of Different Aquifers, Northern China

Abstract

To elucidate the dissolution patterns and kinetic processes of hydrochemical constituents released from minerals in different aquifers of the Taigemiao mining district, the dissolution characteristics during water–rock interactions were analyzed with consideration of the mining context. On this basis, PHREEQC was employed to investigate mineral reaction kinetics during water–rock interactions in the respective aquifers. The results show that the main strata in the study area are Zhidan group, Anding group and Yan'an group from top to bottom, and the corresponding total dissolved solids (TDS) concentrations are 255.99, 4440, and 7344.5 mg/L, respectively. The hydrochemical characteristics of aquifer groundwater have obvious vertical zoning. In the deionized-water immersion experiment, TDS increased from 60.45 to 97.00 to 132.95 mg/L from the Zhidan Group to the Yan'an Group. In the deionized water reaction system, the dissolution–precipitation process of albite and potassium feldspar conforms to the transition state theory equation. Model predictions indicated that Na⁺ concentrations were predicted to stabilize at 25.57 mg/L in the Zhidan Group by Day 120, at 26.76 mg/L in the Anding Formation after 60 days, and to increase to 25.56 mg/L in the Yan'an Formation after 90 days. Accordingly, the time required to reach reaction equilibrium differed among the three experiments.