砂岩铀矿CO_2+O_2地浸初期流场模拟及水化学验证
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摘要
以新疆某砂岩型铀矿床"六注两抽"的地浸单元为研究对象,采用数值模拟与水化学分析相结合的方法,对CO_2+O_2中性地浸初期流场形成进程及其与溶质运移的关系进行了研究。结果表明,在以抽孔和注孔连线为轴线的纺锤形地浸流场中,地浸溶液前锋用时15d抵达抽液孔。SO_4~(2-)和HCO_3~-浓度变化对地浸初期前锋溶液渗流的反应灵敏而精准,是判断CO_2+O_2中性地浸最初阶段溶液前锋运移理想的天然示踪剂。地浸初期Ca~(2+)、Mg~(2+)的碳酸盐都处于过饱和状态,其运移滞后于溶液渗流并与pH的变化密切同步。渗流模拟、水文地球化学模式计算结果以及实际水化学监测数据之间存在良好的互证性,这些方法的综合应用可使地浸流场分析更为客观和可靠。
Taking "six-injection and two-pumping"in-situ leaching units in a sandstone-type uranium deposit in Xinjiang as research object,applying combination of numerical simulation and hydrochemical analysis to form initial flow field of CO_2+O_2 neutral leaching and its relationship with solute transport was studied.The results show that in spindle-shaped flow field with axis of injection-pumping holes,solution front reaches the pregnant holes within 15 days;and concentration changes of SO_4~(2-) and HCO_3~- are sensitive and accurate for infiltration of the forward solution of in-situ leaching.It is an ideal tracer for judging the forward flow of solution in initial stage of CO_2 +O_2 neutral leaching.Initial calcium and magnesium carbonates are both in supersaturated state,and their migrations lag behind solution infiltration and is closely synchronized with change in pH value.There is good mutual proof between calculation results of leaching simulation,hydrogeochemical model and actual water chemical monitoring data.The comprehensive application of these methods is more objective and reliable in analysis of in-situ leaching flow field.
Taking "six-injection and two-pumping"in-situ leaching units in a sandstone-type uranium deposit in Xinjiang as research object,applying combination of numerical simulation and hydrochemical analysis to form initial flow field of CO_2+O_2 neutral leaching and its relationship with solute transport was studied.The results show that in spindle-shaped flow field with axis of injection-pumping holes,solution front reaches the pregnant holes within 15 days;and concentration changes of SO_4~(2-) and HCO_3~- are sensitive and accurate for infiltration of the forward solution of in-situ leaching.It is an ideal tracer for judging the forward flow of solution in initial stage of CO_2 +O_2 neutral leaching.Initial calcium and magnesium carbonates are both in supersaturated state,and their migrations lag behind solution infiltration and is closely synchronized with change in pH value.There is good mutual proof between calculation results of leaching simulation,hydrogeochemical model and actual water chemical monitoring data.The comprehensive application of these methods is more objective and reliable in analysis of in-situ leaching flow field.
引文
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[9]张建华,朱新铖,史骥.某原地浸出铀矿井型及井距优化数值模拟[J].金属矿山,2017(3):25-30.
[10]张勇,马连春,张渤,等.低渗透性铀矿床浸出过程对地下水环境影响的探讨[J].铀矿冶,2017,36(增刊1):75-86.
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[12]彭丁茂,张红军,王树德.原地浸出采铀的水岩作用研究[J].华东地质学院学报,2001,24(1):41-44.
[13]高柏,孙占学,史维浚.地浸过程中铀迁移特征及条件的实验研究[J].地质论评,2003,49(3):316-321.
[14]黄群英.某砂岩铀矿酸法地浸溶质运移与酸化进程分析[J].有色金属(冶炼部分),2015(6):50-54.
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[16]陈崇希,李国敏.地下水溶质运移理论及模型[M].武汉:武汉地质学院出版社,1996.
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