Geochemical characterization studies and batch leaching experiments were conducted to explore the effects of a CO₂ + O₂ leaching system on uranium (U) recovery from ores obtained from an eastern limb of Zinda Pir Anticline ore deposit in Pakistan. The mineralogy of the ore was identified by Electron Probe Micro-analyzer (EPMA) and Scanning Electron Microscope-Energy Dispersive Spectrometer (SEM-EDS), showing that pitchblende is the main ore mineral. XRD was also used along with EPMA and SEM characterization data. Experimental results indicate that U mobility was readily facilitated in the CO₂ + O₂ system with Eh 284 mV and pH 6.24, and an 86% recovery rate of U₃O₈ was obtained. U speciation analysis implied the formation of UO₂ (CO₃)₂²⁻ in the pregnant solution. The plausible mechanism may be attributed to the dissolved CO₂ gas that forms carbonate/bicarbonate ion releasing oxidized U from the ore mineral. However, U recovery in the liquid phase was shown to decrease by higher U(VI) initial concentration, which may be due to the saturation of Fe adsorption capacity, as suggested by an increase in Fe concentration with increasing initial U(VI) concentration in the solid phase. However, further studies are needed to reveal the influencing mechanism of U(VI) initial concentration on U recovery in the solid phase. This study provides new insights on the feasibility and validity of the site application of U neutral in situ leaching.

中文翻译：

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通过CO2 + O2系统的地球化学特征和铀中性浸出-以巴基斯坦ELZPA矿床的铀矿石为例

进行了地球化学表征研究和分批浸出实验，以探索CO ₂ + O ₂浸出系统对从巴基斯坦Zinda Pir Anticline矿床东肢获得的矿石中铀（U）回收的影响。通过电子探针显微分析仪（EPMA）和扫描电子显微镜-能量色散光谱仪（SEM-EDS）鉴定矿石的矿物学，表明沥青闪石是主要的矿石矿物。XRD还与EPMA和SEM表征数据一起使用。实验结果表明，在Eh 284 mV和pH 6.24的CO ₂ + O ₂系统中，U ₃ O _8的回收率达到86％时，U的迁移很容易实现。获得了。U形态分析表明在孕液中会形成UO ₂（CO ₃）₂ ^2-。可能的机理可能是由于溶解的CO ₂形成碳酸盐/碳酸氢根离子的气体从矿石中释放出氧化的铀。但是，液相中的U回收率因较高的U（VI）初始浓度而降低，这可能是由于Fe吸附能力的饱和所致，正如Fe浓度随初始U（VI）浓度的增加而增加所暗示的那样。固相 但是，需要进一步的研究来揭示U（VI）初始浓度对固相中U回收率的影响机制。该研究为U中性原位浸出现场应用的可行性和有效性提供了新的见解。