不同粒度锡采矿废石重金属淋溶规律及影响机制

采用广西某锡矿不同粒度采矿废石进行模拟酸雨动态淋溶试验,研究了不同粒度锡采矿废石的淋溶规律,结果表明,淋溶前期,废石溶出重金属浓度呈上升趋势,Pb、Zn溶出浓度表现出中粒度>细粒度>粗粒度,As溶出浓度最高为0.12mg/L,表现为细粒度>中粒度>粗粒度;淋溶中后期,废石溶出重金属浓度呈平缓甚至缓慢下降趋势,3种重金属溶出规律均表现为细粒度>中粒度>粗粒度, Pb、Zn、As最高溶出浓度分别为0.91,1.05,0.12mg/L.研究了重金属溶出动力学并运用X射线衍射、扫描电镜、能谱仪、比表面积及孔径分布仪和化学测试等手段分析得出了锡采矿废石淋溶影响机制,淋溶前期主要受粒度影响,溶质以对流运移为主;淋溶后期受粒度、空隙率、比表面积、表面结构和形态分布等多重因素影响,溶质以对流运移和分子扩散综合影响为主.本研究方法及结论可为废石重金属防控和监管提供理论依据.

The heavy mental leaching rules and influence mechanism of different particle size of tin mining waste rock

In order to obtain the leaching rule of different particle size of waste rock from tin mining zone, a dynamic simulation test was carried out. Three metal ions, Pb、Zn and As were investigated in the test. Concentrations of heavy metals leached were increasing in the early stage of the test. As leaching time extending, the concentrations of heavy metals leveled off then began to decrease. The influence of the particle size on leaching shown that smaller particle size led to better leaching result. X-ray diffraction、SEM、EDS、Surface Area and Pore Size analysis indicated that the leaching process was primarily influenced by particle size in the early stage of leaching. The solute flow was convective. During the later phase, leaching was influenced by particle size, porosity, specific surface, surface structure and morphologic distribution. In this period, the solute transport was influenced by convection transport and molecular diffusion.