PDF(Pubmed)
Abstract：
The reaction between the lixiviant and the minerals in the aquifer of In-situ uranium leaching (ISL) will result mineral dissolution and precipitation. ISL will cause changes in the chemical composition of groundwater and the porosity and permeability of aquifer, as well as groundwater pollution. Previous studies lack three-dimension numerical simulation that includes a variety of minerals and considers changes in porosity and permeability properties simultaneously. To solve these problems, a three-dimensional reactive transport model (RTM) which considered minerals, main water components and changes in porosity and permeability properties in Bayanwula mine has been established. The results revealed that: (1) Uranium elements were mainly distributed inside the mining area and had a weak trend of migration to the outside. The strong acidity liquid is mainly in the mining area, and the acidity liquid dissolved the minerals during migrating to the outside of the mining area. The concentration front of major metal cations such as K+, Na+, Ca2+ and Mg2+ is about 150m away from the boundary. (2) The main dissolved minerals include feldspar, pyrite, calcite, sodium montmorillonite and calcium montmorillonite. Calcite is the most soluble mineral and one of the sources of gypsum precipitation. Other minerals will dissolve significantly after calcite is dissolved. (3) ISL will cause changes in porosity and permeability of the mining area. Mineral dissolution raises porosity and permeability near the injection well. Mineral precipitation reduced porosity and permeability near the pumping well, which can plugging the pore throat and affect recovery efficiency negatively.
摘要：
原位铀浸出（ISL）含水层中浸出剂与矿物之间的反应将导致矿物溶解和沉淀。ISL会引起地下水的化学成分和含水层的孔隙度和渗透率的变化，以及地下水污染。以前的研究缺乏三维数值模拟，包括各种矿物，并同时考虑孔隙度和渗透性的变化。为了解决这些问题,考虑矿物的三维反应输运模型(RTM)，建立了巴彦乌拉矿主要水成分和孔隙度和渗透率的变化。结果表明:(1)铀元素主要分布在矿区内部,对外迁移趋势较弱。强酸性液体主要在矿区，酸性液体在向矿区外迁移过程中溶解了矿物。主要金属阳离子如K+的浓度前沿，Na+,Ca2+和Mg2+距离边界约150m。(2)主要溶解矿物包括长石,黄铁矿,方解石,蒙脱石钠和蒙脱石钙。方解石是最易溶的矿物，也是石膏沉淀的来源之一。其他矿物在方解石溶解后将显著溶解。(3)ISL会引起矿区孔隙度和渗透率的变化。矿物溶解提高了注入井附近的孔隙度和渗透率。矿物沉淀降低了抽油井附近的孔隙度和渗透率，会堵塞孔喉，对采收率产生负面影响。
