Department of Environmental Engineering, Chonbuk National University, 567 Baekje-daero, Deokjin, Jeonju, Jeollabukdo, 561-756, Republic of Korea.
Environ Geochem Health. 2013 Dec;35(6):735-43. doi: 10.1007/s10653-013-9531-1. Epub 2013 Jun 11.
In Korea, the heavy metal pollution from about 1,000 abandoned mines has been a serious environmental issue. Especially, the surface waters, groundwaters, and soils around mines have been contaminated by heavy metals originating from acid mine drainage (AMD) and mine tailings. So far, AMD was considered as a waste stream to be treated to prevent environmental pollutions; however, the stream contains mainly Fe and Al and valuable metals such as Ni, Zn, and Cu. In this study, Visual MINTEQ simulation was carried out to investigate the speciation of heavy metals as functions of pH and neutralizing agents. Based on the simulation, selective pH values were determined to form hydroxide or carbonate precipitates of Cu, Zn, and Ni. Experiments based on the simulation results show that the recovery yield of Zn and Cu were 91 and 94 %, respectively, in a binary mixture of Cu and Zn, while 95 % of Cu and 94 % of Ni were recovered in a binary mixture of Cu and Ni. However, the recovery yield and purity of Zn and Ni were very low because of similar characteristics of Zn and Ni. Therefore, the mixture of Cu and Zn or Cu and Ni could be recovered by selective precipitation via pH adjustment; however, it is impossible to recover selectively Zn and Ni in the mixture of them.
在韩国，约 1000 个废弃矿山的重金属污染已成为一个严重的环境问题。特别是矿山周边的地表水、地下水和土壤受到了源自酸性矿山排水（AMD）和矿山尾矿的重金属污染。到目前为止，AMD 被认为是一种需要处理的废水，以防止环境污染；然而，该废水中主要含有 Fe 和 Al 以及 Ni、Zn 和 Cu 等有价值的金属。在这项研究中，采用 Visual MINTEQ 模拟研究了重金属的形态作为 pH 值和中和剂的函数。基于模拟结果，确定了选择 pH 值以形成 Cu、Zn 和 Ni 的氢氧化物或碳酸盐沉淀。基于模拟结果的实验表明，在 Cu 和 Zn 的二元混合物中，Zn 和 Cu 的回收率分别为 91%和 94%，而在 Cu 和 Ni 的二元混合物中，Cu 的回收率为 95%，Ni 的回收率为 94%。然而，由于 Zn 和 Ni 的特性相似，Zn 和 Ni 的回收率和纯度都非常低。因此，通过 pH 值调节进行选择性沉淀可以回收 Cu 和 Zn 或 Cu 和 Ni 的混合物；然而，不可能从它们的混合物中选择性地回收 Zn 和 Ni。
