Mineral Reaction Kinetics During Water–Rock Interactions of Julong Hot Springs, Northern China

To elucidate the water–rock interaction mechanisms of the Julong Hot Springs in Changbai Mountain, this study first analyzed the leaching patterns of hydrochemical components in water–rock interactions. The PHREEQC software was then utilized to calculate mineral saturation indices and mineral phase diagrams, thereby exploring the thermodynamic equilibrium state of water–rock interactions. A mineral reaction kinetics model was constructed to investigate the reaction rates of rock minerals and quantify their kinetic processes. The results show that (1) within 72 h of reaction, Na + is the predominant cation, and HCO 3 − is the predominant anion in both deionized water–rock interaction and geothermal water–rock interaction. The hydrochemical types are all HCO 3 –Na. (2) In deionized water–rock interaction and geothermal water–rock interaction, albite, K‐feldspar, and quartz are the main minerals that dissolve. In deionized water–rock interaction and geothermal water–rock interaction, the dissolution of albite and K‐feldspar occurs in the gibbsite and kaolinite stages, respectively, and both processes occur in the early stages of the reactions. (3) In the deionized water–rock interaction, the dissolution and precipitation of albite, K‐feldspar, and quartz conform to the transition state theory equation. During the model prediction process, the concentrations of Na + and K + exhibited a significant increase within the initial 180 days, after which the increase slowed and gradually stabilized. The absolute values of the molar changes in albite and K‐feldspar exhibit complex variations, initially increasing, then decreasing, followed by another increase, and finally decreasing. The maximum molar changes of albite and K‐feldspar were observed at 5 days, with respective values of −1.42e − 3 and −6.27e − 4 mol. The molar change of quartz initially increased and then decreased, reaching its maximum value of 4.26e − 4 mol at 60 days. By 540 days, the molar changes of minerals approached 0, indicating that the water–rock interaction had reached equilibrium.