某砂铀矿地浸单元酸浸初期溶质运移与溶液渗流关系

摘要

采用水文化学分析及数值模拟方法,对新疆某砂岩铀矿地浸单元酸法地浸初期SO42-、H+、Ca2+等主要溶质离子的运移与溶液渗流之间的关系进行了探讨.SOi-前锋用时8d运移至抽孔,40 d后抽、注液SO:-浓度开始同幅变化,表明大部分溶液已渗流至抽孔,根据渗流模拟计算,在流向抽液孔的溶液中,最快的可在5～6 d抵达,40 d时83％的溶液抵达;H+在水岩作用过程中被部分消耗,其前锋21 d运移抽液孔,而由H+溶蚀出来的Ca2+、Mg2+则与SO42-同步运移;66 d地浸流场达到H+的补给与消耗平衡,表明绝大部分溶液已经达到抽液孔,而根据计算,这一比例已经达到94％.水文化学分析与水动力计算结果吻合.%Relationship between solution flow and transportation of solute ions,such as SO42-,H+,Ca2+,and Mg2+,which are closely related with water-rock interaction of in-situ uranium leaching,were analyzed by hydrogeochemistry analysis and numerical simulation.Transportation characteristics of SO42-reveal that it takes 8 days for the earliest leaching solution to reach extraction well,and 40 days to form a stable flow field.Simulation results show it takes 5～6 days for the earliest solution flowing toward extraction well to reach production well and 40 days for the rest 83％.Retarded by water-rock interaction,the forefront of H+ plume reaches extraction well 13 days later than that of SO42-;as water-rock interaction products,Ca2+ and Mg2+ transport synchronously with SO42-;and it takes 66 days to built a balance between supply and consumption of H+,forming stable geochemical field for uranium leaching.According to simulation results,94％ of solution flowing toward extraction well reaches production well on the 66th day.The results of solution flow simulation are consistent with those of hydrogeochemistry analysis.