化学因素作用下某尾矿砂渗透特性及污染防治研究

尾矿作为矿山开采过程中不可避免的固体废弃物，其渗透（淋滤）特性是诱发环境污染的关键因素之一。以某铜矿山尾矿为例，采用自主设计的渗透（淋滤）装置，探讨了化学因素作用下不同干密度尾矿砂的渗透及淋滤特性，揭示了不同pH溶液环境下尾矿砂的渗透系数变化规律；针对尾矿淋滤对环境的污染现象，采用Visual MODFLOW数值软件，模拟了Cu2+在尾矿库内的迁移规律；并基于工程屏障阻滞理念，建立了污染物迁移模型，探讨了重金属污染的防治效果。结果表明：①随着溶液pH值降低，尾矿渗透系数逐渐增大，最大可增至1~2个数量级；②在盐溶液环境下，随着NaCl浓度升高，尾矿渗透系数先缓慢增加再逐渐降低；③ 工程屏障能够长期且有效阻滞污染源，可作为矿山环境污染防治及修复的重要手段。基于上述分析结果，提出了尾矿库重金属污染防治的工程措施，为相关工程实践提供借鉴。

Permeability Characteristics and Pollution Control of a Tailings Considering the Chemical Factors

As an inevitable solid waste during the mining process， the permeability/leaching property of tailings is normally considered as one of the most critical factors for environmental pollution. In this study， a self-designed infiltration/leaching device was designed to conduct the permeability tests of tailings from a copper mine. And the influences of chemical factors，dry density and pH on the permeability property of tailings were investigated. In order to study the environmental pollution caused by tailings leaching， the visual Moldflow software was applied to simulate the migration process of Cu2+ in tailings pond. Moreover，based on the retention concept of engineered barrier，a contaminant transport model was established to simulate and assess the control effects of heavy metal pollution.Test results revealed that:①The permeability coefficient of tailings gradually increased with the decrease of pH value，and the maximum permeability coefficient can increase 1~2 orders of magnitude.②Under the environment of saline solution，as the NaCl concentration increased， the permeability coefficient firstly increased and then decreased. ③The simulation results implied that the engineered barrier could chronically and effectively retain the pollution source， and could be considered as an important preventing and repairing method for the mine environment pollution. Based on the above analysis results， the engineering measures were proposed for the prevention of heavy metal pollution in mines， and these measures could provide imported guidance for relative engineering practices.