丁二酮肟分光光度法测定富铼渣中铼

称取0.20 g样品于高铝坩埚中,置于马弗炉中升温至250 ℃,恒温30 min以驱除硫和砷,再加入3.5 g过氧化钠于730 ℃熔解7 min,以水浸出熔融物后,加热微沸约5 min以促进过氧化钠产生的过氧化氢分解完全,加水定容后,过滤,加入1滴对硝基酚溶液,滴加盐酸(1+6)至溶液黄色刚褪去(pH≈1),加水至20 mL,再加入5 mL 400 g/L柠檬酸溶液、5 mL盐酸(1+3)、5 mL 10 g/L丁二酮肟乙醇溶液、5 mL 250 g/L氯化亚锡溶液进行显色测定,建立了丁二酮肟分光光度法测定富铼渣中铼含量的方法。实验表明:铼的质量浓度在100～600 μg/100 mL范围内与其吸光度符合比尔定律,方法检出限为11.3 μg/mL。干扰试验表明样品中共存离子不干扰测定。将方法用于两个富铼渣管理样品及两个实际样品中铼的测定,测定值与参考值相符,相对标准偏差(RSD,n=22)为0.69%～1.1%,回收率为99%～100%。

Determination of rhenium in rhenium-rich slag by dimethylglyoxime spectrophotometry

After 0.20 g of sample was transferred into high-aluminum crucible, the crucible was put into muffle furnace at 250 ℃ for 30 min to remove sulfur and arsenic. Then, 3.5 g of sodium peroxide was added, and they werefused at 730 ℃ for 7 min. The melt was leached with water, and the solution was heated to slight boiling for about 5 min to accelerate the complete decomposition of hydrogen peroxide generated from sodium peroxide. Then, the solution was diluted to the constant volume followed by filtration. One drop of paranitrophenol solution was added and hydrochloric acid(1+6) was dripped into solution until the yellow color just disappeared (pH≈1). The solution was diluted to 20 mL. Then, 5 mL of 400 g/L citric acid solution, 5 mL of hydrochloric acid (1+6), 5 mL of 10 g/L dimethylglyoxime ethanol solution and 5 mL of 250 g/L stannous chloride solution were added for coloring. Consequently, a method was established for determination of rhenium in rhenium-rich slag by dimethylglyoxime spectrophotometry. The experiments showed that Beer’s law was obeyed for rhenium in mass fraction range of 100-600 μg/100 mL with absorbance. The detection limit of method was 11.3 μg/mL. The interference test indicated that the coexisting ions in sample had no interference with the determination. The proposed method was applied to the determination of rhenium in two rhenium-rich slag control samples and two actual samples. The results were basically consistent with the reference values. The relative standard deviations (RSD, n=22) were in range of 0.69%-1.1%, and the recoveries were between 99% and 100%.