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模拟生物堆浸工艺条件,在硫酸铁酸性介质体系下,进行硫砷铜矿化学浸出动力学实验研究。硫砷铜矿化学性质稳定,在初始Fe3+浓度31 g·L-1,Fe2+浓度0.02 g·L-1,初始p H=1.00±0.05,氧化还原电位恒定在(900±5)m V,30℃条件下浸出96 h,硫砷铜矿的浸出率仅有2.49%。不同电位对硫砷铜矿浸出的影响结果表明,硫砷铜矿的浸出率与电位呈弱正相关,30,45,60,75℃时硫砷铜矿的浸出率与电位的关联指数分别为0.0037,0.0053,0.0062,0.0120。低温下电位对溶解速率影响很小,高温下较显著。研究了温度对硫砷铜矿浸出的影响,氧化还原电位在800 m V时,温度在30~75℃范围,硫砷铜矿硫酸铁酸性化学浸出的表观活化能Ea=57.87 k J·mol-1。实验结果表明,硫酸铁酸性浸出硫砷铜矿符合典型的缩核模型,速率受表面化学反应控制,而非扩散。结合低品位次生硫化铜矿生物堆浸生产实际,为生产实践提出了工艺优化措施。
Simulated biological heap leaching process conditions, ferric sulfate acidic medium system, the chemical reaction of sulfur arsenic copper chemical kinetics. The arsenic-copper minerals are chemically stable with the initial Fe3 + concentration of 31 g · L-1, the Fe2 + concentration of 0.02 g · L-1, the initial p H = 1.00 ± 0.05 and the redox potential constant at (900 ± 5) mV, 30 ℃ leaching 96 h, arsenic copper mine leaching rate of only 2.49%. The effect of different potentials on the extraction of arsenic, copper and copper minerals showed that the leaching rate of arsenic and copper arsenic was weakly positively correlated with the potential. The correlation indices of the extraction rates and potentials of arsenic, copper and copper at 30, 45, 60 and 75 ℃ were 0.0037, 0.0053, 0.0062, 0.0120. Potential at low temperature has little effect on the dissolution rate, more significant at high temperatures. The effect of temperature on the leaching of arsenopyrite and copper was studied. The apparent activation energy Ea was 57.87 kJ · mol-1 when the redox potential was 800 mV and the temperature ranged from 30 to 75 ℃. -1. The experimental results show that the ferric sulfate leaching of arsenic and copper minerals conforms to the typical nucleation model, and the rate is controlled by the surface chemical reaction rather than diffusion. Combining with the actual production of low-grade secondary copper sulfide bio-heap leachate, process optimization measures are put forward for production practice.