Field Trial on Enhanced In-situ Leaching of Uranium by CO2+O2 Leaching
Received:August 30, 2020   Revised:September 02, 2020   Accepted:September 04, 2020      Published Online:December 03, 2020
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DOI:doi:10.3969/j.issn.1007-7545.2020.12.010
KeyWord:sandstone type uranium deposit, CO2+O2 in-situ leaching, intensive leaching by HCO3-
              
AuthorInstitution
ZHANG Qing-lin 新疆中核天山铀业有限公司;东华理工大学核资源与环境国家重点实验室
ZHOU Yi-peng 东华理工大学核资源与环境国家重点实验室
MU Zhi-jun 新疆中核天山铀业有限公司
YANG Xiao-yu 新疆中核天山铀业有限公司
LI Guang-rong 东华理工大学核资源与环境国家重点实验室
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Abstract:
      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.
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