Liu Chao, Hao Yan, Liu Xingzhou, Peng Hu, Li Lei, Fu Xiaofei, Gu Shefeng, Nie Zhiyang, Zhou Ai Hong
National Key Laboratory of Continental Shale Oil, Northeast Petroleum University, Daqing, Heilongjiang 163318, China.
Northeast Geological S&T Innovation Center of China Geological Survey, Shenyang, Liaoning 110034, China.
ACS Omega. 2025 Aug 25;10(35):39791-39798. doi: 10.1021/acsomega.5c03458. eCollection 2025 Sep 9.
Shale is a primary host for both organic matter and uranium within sedimentary basins. Whether uranium within shale can be released from the rock matrix into formation fluids is a critical factor in evaluating its potential as a source of ore fluids for sandstone-hosted uranium deposits, yet it remains a subject of ongoing debate. This study addresses this question by investigating the chemical speciation of uraniuma fundamental determinant of its stabilitythrough thermal simulation experiments and a sequential extraction method. The results demonstrate that uranium release potential strongly depends on its speciation within shale. Weak-acid-extractable and reducible fractions exhibit a heightened tendency to release into fluids, with 80.7% and 63.9% released at temperatures below 100 °C, respectively. Oxidizable species demonstrate partial release (29.4%) at temperatures exceeding 200 °C, whereas residual fractions remain in the solid phase. The released uranium reaches concentrations in aqueous solutions and oil at levels comparable to ore-forming fluids in sandstone-hosted uranium deposits. However, due to the limited understanding ofuranium's mobility potential in oxygen-deficient fluids, its potential as a source for such fluids requires further investigation.
页岩是沉积盆地中有机质和铀的主要宿主。页岩中的铀能否从岩石基质中释放到地层流体中，是评估其作为砂岩型铀矿床矿液来源潜力的关键因素，但这仍是一个持续争论的话题。本研究通过热模拟实验和顺序提取法研究铀的化学形态（其稳定性的基本决定因素）来解决这个问题。结果表明，铀的释放潜力强烈取决于其在页岩中的形态。弱酸可提取和可还原部分表现出更高的释放到流体中的倾向，在低于100°C的温度下分别有80.7%和63.9%被释放。可氧化物种在超过200°C的温度下表现出部分释放（29.4%），而残留部分则保留在固相中。释放的铀在水溶液和油中的浓度与砂岩型铀矿床中的成矿流体相当。然而，由于对铀在缺氧流体中的迁移潜力了解有限，其作为此类流体来源的潜力需要进一步研究。
