氢还原重量法测定硝酸铑产品中铑含量

根据冶金工艺中铑的精炼原理,建立了氢还原重量法测定硝酸铑产品中铑含量的方法。研究并优化了测定条件,考察了杂质元素对铑分析结果的影响。结果表明:在0.3～0.9 mol/L硝酸介质中,硝酸铑与氯化铵形成一种(NH₄)₃ RhCl₆红色络合物晶体,该晶体经过在约100 ℃烘干水分、350 ℃分解铵盐、750 ℃氢还原为海绵铑和105 ℃干燥后可以采用重量法测定其中的铑。用该方法测定硝酸铑产品中质量分数为6.55%、7.36%、8.05% 、9.99%和20.05%铑的极差(R)为±0.01%,标准偏差(SD)为0.004 1%,相对标准偏差(RSD,n=22)在0.02%～0.06%范围。本法测定结果较YS/T 594-2006标准配套分析方法的准确度和精密度高。

Determination of rhodium in rhodium nitrate products by hydrogen reduction gravimetry

According to the principle of metallurgical refining of rhodium, a method for the determination of rhodium in rhodium nitrate products by hydrogen reduction gravimetry was established. The conditions for the determination of rhodium were investigated and optimized. The effect of impurities on the determination results of rhodium was also tested. It was found that, in the medium of 0.3-0.9 mol/L HNO₃, rhodium nitrate and ammonium chloride formed a red (NH₄)₃RhCl₆ crystal complex in which rhodium could be determined by gravimetry after a series of treatment: firstly, it was dried at 100 ℃; then, ammonium salt in it was decomposed at 350 ℃; lastly, the obtained matter was reduced into rhodium sponge by hydrogen at 750 ℃ and dried at 105 ℃. The method was employed to determine rhodium of 6.55%, 7.36%, 8.05%, 9.99% and 20.05%, in rhodium nitrate with the range (R) of ±0.01 %, the standard deviation (SD) of 0.004 1% and the relative standard deviation(RSD,n=22) of 0.02%-0.06%. The accuracy and precision of this method were higher than YS/T 594-2006 standard method.