安徽铜陵狮子山矿田铜、金共生与分离的热力学研究

狮子山矿田是安徽铜陵矿集区内最具代表性的大型铜金多金属矿田.矿田内铜、金矿床或矿体既各自独立产出,义相互共生或伴生,铜矿化和金矿化在时间上和空间上存在既共生又分离的现象.本文选择矿田内代表性铜矿床和金矿床开展系统的流体包裹体地球化学研究,并进行成矿流体中铜、金溶解度的热力学理论计算和1分析,探索铜、金共生与分离的机制和...

Thermodynamic study for the association and fractionation of copper and gold in the Shizishan orefield, Tongling, Anhui Province

Shizishan orefield is the most representative large-size copper-gold orefield in Tongling ore district, Anhui Province. Copper mineralization and gold mineralization existed in association or fractionation either temporally or spatially. Based on systematic study of the fluid inclusion for the copper deposits and the gold deposits, the solubility of Cu, Au transportation complexes species has been calculated according to obtained thermodynamic parameters, the mechanism and the key factors to the association and fractionation between copper and gold in ore-forming fluid has been discussed. It is concluded that, in the ore-forming fluid of the Shizishan orefield, the dominant Cu complexes species were CuCl2- and CuCl0 which were affected by the concentration of Cl- anion, the dominant Au complexes species were Au(HS)¬2- and Au2S(HS)22- affected by the total sulfur concentration. The unloading and precipitation of both Cu and Au in the ore-forming fluid was controlled by temperature, pH, fO2 and fS2. The great difference of complexes species and solubility between copper and gold dissolved in the ore-forming fluid responded distinctly to physicochemical conditions, which led to their precipitation difference in time and space, and the temporal-spatial separating of copper mineralization and gold mineralization.