基于信息熵理论的原地爆破浸出采铀堆场地下水监测网络优化与渗漏示踪

Uranium resources in China characterize low grade and reserve,making the cost of mining and hydrometallurgy high and environmental impact serious.Their mining and hydrometallurgy using stope leaching uranium has wide prospects, however, the disadvantages,loss of uranium and groundwater pollution, restrain application of the technology and persecute the technician since artificial impervious barrier bottom of the uranium ore dump can't ensure leachant and leachate not to seep into ground due to the characteristic of the technology. Thus it is very important for implementing effectivly remedial measures on seeage to find out the methods of quickly monitoring and precisely judging seeping location. In the project, the correlation degree between variation of water quality and water table in the monitoring well near of the site of stope leaching uranium and the volume of spraying leachant will be studied, the information entropy reflecting leachant and leachate seepage from uranium ore dump to groundwater will be calculated, the relativity betweem the composition of the ore and host and quality of groundwater in the site will be researched, the tracer reflecting leachant and leachate seeping will be chosen to find out the green tracer could quickly analyze and exactly reflect seeping,the multi-object optimization model on the groundwater monitoring network and the estimation model on the amount of seepage will be established to decide the optimized location and depth, number of the monitoring wells, it has an important meaning for increasing the resource recovery rate of uranium and protecting environment.

我国的铀矿资源品位低、储量少，采冶成本高，环境影响大。原地爆破浸出技术对低品位铀矿资源回收具有广阔发展前景。但是，工艺特殊性造成原地爆破浸出采铀堆场防渗措施难以保证，渗漏流失铀资源及对地下水的影响一直困扰工程技术人员，也抑制着该技术的应用。为了采取有效的应急渗漏处理措施，寻找快速监测、准确判断堆场渗漏的方法就显得尤为重要。本项目研究原地爆破浸出堆场监测孔的水质、水位变化与堆场喷淋量的关联度，计算每个监测孔水质变化、水位变化及场址地质条件反映渗漏的信息熵值；研究矿石、围岩的化学成分与地下水水质的相关性，选择堆场渗漏的示踪剂；建立原地爆破浸出采铀堆场地下水监测网络信息熵多目标优化模型与渗漏量估算模式，确定监测孔的最佳位置、孔深、数量，寻找快速检测、简单、环境友好能准确判断堆场渗漏的示踪剂，对提高资源回收率、防治环境污染具有重要意义。

随着我国核电的大力发展，核燃料的需求量越来越大，而我国铀矿资源品位低，储量少，传统的采冶技术成本高。原地爆破浸出采铀技术具有成本低、综合污染少，针对低品位铀矿石的资源回收具有非常广阔的发展前景。但是，其工艺特殊性造成原地爆破浸出采铀堆场防渗措施难以保证，铀浸出液可能渗漏流失及其对地下水的潜在影响一直令人困扰，也抑制着该技术的应用。为了采取有效的应急处理措施，寻找快速监测、准确判断堆场渗漏的方法尤为重要。本研究重点研究了适用于判断原地爆破浸出采铀堆场渗漏的示踪剂，静态实验研究表明示踪剂荧光素钠不降低铀的浸出，添加0.008mol/L表面活性剂SDS 能有效降低溶浸剂与矿石间的界面张力，降低值达到52.94%，从而强化铀的浸出，使铀浸出率从79.15%提升至85.49%，同时降低了围岩与矿石对荧光素钠的吸附，使分配系数从7.42mL/g减少到5.81mL/g。室内示踪模拟表明了SDS使铀矿石浸出率提高了9.01%，使示踪剂荧光素钠在铀矿石中分配系数减少了36.64%，阻滞系数减少了30.11%，尤其是使得初始穿透的荧光素钠的浓度提高了20.8倍，因此在原地爆破浸出采铀中采用荧光素钠作为示踪剂，添加表面活性剂SDS，判断浸出液渗漏是可行的。同时也研究了表面活性剂MES协同硫酸溶液对废渣铀浸出的动力学，研究表明了表面活性剂MES能提高硫酸对废渣铀的浸出率，其浸出过程受流体滞留膜扩散控制，其表观活化能为29.523 kJ/mol，对促进铀资源的回收有很大的意义。另外，以改性锯末与改性炭化锯末作为PRB墙的吸附材料处理铀废石与铀尾矿渗滤液，回收铀资源，开展了改性锯末与改性炭化锯末吸附铀的机理研究，研究表明了氯化锌改性的锯末对铀的吸附主要有表面吸附和酰胺基、羟基、酮基和芳烃C-H键等基团参与的络合吸附；以碳酸氢钠改性的炭化锯末对铀的吸附主要有表面吸附和酰胺基、醛基、羧基等基团参与的络合吸附，其吸附过程更符合准二级动力学方程，热力学更符合Freundlich吸附等温线方程，可为锯末作为PRB材料处理渗滤液的工艺参数研究提供参考。