【摘要】 成矿流体的温度、压力等物理条件变化影响铀溶解、沉淀能力,在热液型铀矿研究中对揭示铀富集沉淀机制具有重要意义。以沙子江铀矿床为主要研究对象,进行微量元素化学分析和物理化学条件模拟实验。变温实验和恒压变温实验结果表明在饱和蒸气压及6.89 MPa条件下,铀在0.5%NaHCO3介质中的优势溶解温度为80℃;在20 MPa条件下,相当于地下埋深约702～800 m, 150℃为铀的优势溶解温度; 200℃恒温条件下,随压力的增加,铀在0.5%NaHCO3介质中的溶解能力逐渐降低。研究表明来自地壳深部的含铀成矿流体随多期次的岩浆活动引起的温度波动有利于铀富集沉淀,减压作用中压力变化并非铀富集沉淀的直接因素。更多还原

【Abstract】 Temperature, pressure and other physical conditions of ore-forming fluids affect the capacity of uranium dissolution and precipitation, which is of great significance in revealing the enrichment mechanism of uranium in hydrothermal uranium deposits. The chemical analysis of trace elements and physicochemical conditions simulation experiments were carried out with the samples from Shazijiang uranium deposit. The temperature experiment with and without pressure constrain showed that under the condition of saturated vapor pressure and 6.89 MPa, the advantage uranium dissolved temperature was 80 ℃ in 0.5% NaHCO3 and 150 ℃ was the advantage dissolved temperature under 20 MPa which is equivalent to about 702 to 800 m underground depth. Under 200 ℃ condition, the uranium dissolved capacity in 0.5% NaHCO3 medium gradually reduce with the increase of the pressure. It shows that the temperature fluctuation of uranium-bearing ore-forming fluid from crust with multiple periods of magmatic activities is favorable for uranium enrichment and precipitation, and the pressure change during the decompression is not a direct factor for uranium enrichment and precipitation.更多还原