过氧化氢在黄铁矿的溶解过程中对铼-锇信号强度及年龄的影响

Influence of H_2O_2 on the Signal Intensity of Rhenium,Osmium and Re-Os Age in the Process of Dissolution for Pyrite

对黄铁矿在高温高压密闭的Carius管溶解过程中出现的黄色沉淀物进行了定性研究。在黄铁矿中加入少量的辉钼矿及185Re和190Os混合稀释剂,在常规的逆王水溶矿过程中加入适量H2O2,用ICP-MS检测,研究了H2O2对Re、Os信号强度变化及同位素交换平衡产生的影响。结果表明,在黄铁矿溶解过程中出现的黄色沉淀物为羟基硫酸铁(FeOHSO4)而不是单质硫,它是由于密闭的Carius管内氧化性不够而生成的。H2O2的加入对ICP-MS测定Re信号强度没有影响,而对Os则有显著的改善,但这种改善并未影响到加入的185Re和190Os稀释剂与样品中的Re和Os达到同位素交换平衡,因而也不影响到样品的Re、Os含量及最终的Re-Os同位素年龄计算。

Qualitative study was made to the yellow precipitate appeared in the dissolution of pyrite in sealed Carius tube with high temperature and high pressure. Influence of H2O2 added with routine reverse aqua regia on the signal intensity of rhenium and osmium measured by ICP-MS and equilibrium of isotope exchange was also studied. Results showed that the yellow precipitate was hydroxide iron sulfate （FeOHSO4 ） but not sulfur. Adding H2O2 did not affect the signal intensity for rhenium but enhanced clearly for osmium. But this improvement for osmium signal intensity also did not affect the equilibrium of isotope exchange between ^185Reand ^190Os spikes with Re and Os in sample. Hence it did not affect the final result of Re and Os content and Re-Os age.