CO2+O2地浸采铀强化浸出试验研究

新疆蒙其古尔铀矿床CO2+O2地浸采铀工艺中，铀浓度与HCO3-呈显著的正相关关系，但经过浸出初期后，提高CO2加入量不能有效提升体系HCO3-浓度，而对多数地浸单元的矿化条件而言，HCO3-浓度也尚未达最佳浸出需求。为此在该矿床某采区，采用补加碳酸氢铵和提高CO2加入量相配合的工艺，开展了强化浸出试验。结果表明，强化浸出效果显著，该采区浸出液中HCO3-从850 mg/L提升至1 200 mg/L，单孔铀浓度提升1.73~44.33 mg/L，集合样铀浓度提升8 mg/L。将pH调控在6.2~6.3和降低O2加入量稳定SO42-浓度，能避免强化浸出过程中发生碳酸钙和硫酸钙的沉淀，抽、注流量也并未受到影响。该强化浸出技术在多采区应用取得了良好的浸出效果和经济效益，是对该矿床CO2+O2浸出工艺的进一步优化。

Field Trial on Enhanced In-situ Leaching of Uranium by CO2+O2 Leaching

Uranium concentration has a significant positive correlation with HCO3- during CO2+O2 in-situ leaching of uranium process from Mengqiguer sandstone type uranium deposit in Xinjiang. However, after the initial stage of leaching, HCO3- concentration of leaching solution can be not increased effectively by adding more CO2. For most leaching units of Mengqiguer deposit, HCO3- concentration does not yet meet the optimal leaching requirement. So, in a selected mining area of the deposit, a trial of supplementing bicarbonate ammonia combined with increasing of CO2 amount was carried out to enhance leaching intensity. The study results show that effect of enhanced leaching is significant: HCO3- concentration rises from 850 mg/L to 1 200 mg/L, which results in that uranium concentration of pregnant solution of single-well rises by 1.733-44.33 mg/L, and that of mix pregnant solution by 8 mg/L. While pH value of leaching solution is controlled at 6.2-6.3 and SO42- concentration stabilized by reducing O2, precipitation of calcium carbonate and calcium sulfate will not happen during enhanced leaching process. In addition, pumping and injection capacities are not affected passively. This enhanced leaching technology is a further optimization of CO2+O2 leaching process in Mengqiguer deposit, and good leaching effect and economic benefits result from its applications in mining areas.