德兴铜矿尾矿库重金属的浸出

摘要

The wastewater source of 4# tailing pond in Dexing copper mine consists of alkaline flotation pulp and acid mine drainage (AMD) from the nearby opencast mine. Therefore, the heavy metals in tailing ore are very likely to be released due to acidification from AMD. The leaching behaviors of Zn, Cu, Fe and Mn in mine tailings from Dexing copper mine were investigated by a series of laboratory batch experiments. The effectcs of pH, temperature, particle size and contact time on the leachability of such heavy metals were examined. It was evident that Zn, Cu, Fe and Mn were major heavy metals in the tailings while gangue minerals like quartz were major constituents in examined tailings. The tailing dissolution reaction was controlled by the acid, whose kinetics could be expressed according to the heterogeneous reaction models and explained by a shrinking core model with the surface chemical reaction as the rate-controlling step. The leachability of all metals examined depended on pH and contact time. The batch studies indicated that the maximum leaching ratios of Zn, Cu, Fe and Mn at pH 2.0 were 5.4%, 5.8%, 11.1%and 34.1%, respectively. The dissolubility of all metals examined was positively correlated to the temperatures. The particle size would not change dissolution tendency of those heavy metals, but decrease the concentrations of leached heavy metals.%德兴铜矿的4＃尾矿库废水来源包括碱性浮选矿浆和附近露天矿山的酸性废水(AMD)。因此，酸性矿山废水的酸化作用极可能造成尾矿中重金属的浸出。通过实验室的批次实验对德兴铜矿尾矿中锌、铜、铁和锰的浸出行为进行了研究，对pH值、温度、颗粒大小和接触时间对重金属浸出的影响进行了讨论。结果表明，锌、铜、铁和锰是尾矿中的主要重金属，石英类脉石矿物是尾矿的主要成分。尾矿的溶解反应受酸度控制，其动力学可以根据非均相反应的模型来表达，通过表面化学反应作为速率决定步骤的核收缩模型来解释。这些重金属的浸出依赖于pH值和接触时间。批次实验研究得出，锌、铜、铁和锰在pH=2.0时的最大浸出率分别为5.4%、5.8%、11.1%和34.1%。重金属的溶出与温度呈正相关性。颗粒大小不会改变这些重金属的浸出趋势，但会略微导致重金属的最高浓度和平均水平的下降。