某砂铀矿地浸单元酸浸初期溶质运移与溶液渗流关系

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SO_4~(2-)、H~+、Ca~(2+)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。SO_4~(2-)前锋用时8d运移至抽孔,40d后抽、注液SO_4~(2-)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5~6d抵达,40d时83%的溶液抵达;H~+在水岩作用过程中被部分消耗,其前锋21d运移抽液孔,而由H~+溶蚀出来的Ca~(2+)、Mg~(2+)则与SO_4~(2-)同步运移;66d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 Solute Transportation and Leaching Solution Flow during Early Period of Acid In-Situ Leaching at One Sandstone-Type Uranium Deposit

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.