萃取分离-重量法和电感耦合等离子体原子发射光谱法分别测定金铂废液中金和铂

准确测定金铂废液中含量悬殊的Au、Pt含量对市场交易和冶金生产金属平衡有重要意义。分别使用火试金-重量法和电感耦合等离子体原子发射光谱法(ICP-AES)测定金铂废液中高含量Au和低含量Pt时,由于Au和Pt互相干扰,造成其测定结果的误差较大,不能满足市场交易和冶金生产金属平衡考察对绝对误差不大于±0.05%的要求。将冶金精炼金的技术和ICP-AES测定Pt的方法相结合,建立了乙醚萃取分离-草酸铵还原-重量法测定Au和乙醚萃取分离-ICP-AES测定Pt的方法。优化后的条件如下:2 g金铂废液,共使用30 mL乙醚分3次萃取分离金(Ⅲ),再用2.4~3.2 g草酸铵还原Au(Ⅲ)40 min,并在105 ℃烘干55 min后,用重量法测定Au;0.15 g金铂废液,共使用8 mL乙醚分2次萃取分离Au(Ⅲ),在10%盐酸介质中用ICP-AES测定Pt。分别按照两种实验方法测定金铂废液中84%~89%(质量分数,下同)Au和0.5%～5%Pt,Au测定结果的相对标准偏差(RSD,n=11)为0.030%～0.036%,Pt测定结果的相对标准偏差(RSD,n=11)为0.12%～0.30%;Au和Pt的加标回收率分别为99.88%～100.19%和99.45%～100.36%。

Respective determination of gold and platinum in gold-platinum waste liquid by gravimetry and inductively coupled plasma atomic emission spectrometry with extraction separation

It is of great significance to accurately determine Au and Pt in the gold-platinum waste liquid with large disparities in content for the metal balance in market transactions and metallurgical production. During the respective determination of high content Au and low content Pt in gold-platinum waste liquid by fire assay-gravimetry and inductively coupled plasma atomic emission spectrometry (ICP-AES), the error of determination results was relatively high due to the mutual interference between Au and Pt, which could not meet the requirements in the metal balance in market transactions and metallurgical production that the absolute error should not be higher than ±0.05%. Combining the technology of metallurgical refining gold with the determination method of Pt by ICP-AES, Au was determined by ether extraction separation-ammonium oxalate reduction-gravimetry and Pt was determined by ether extraction separation-ICP-AES. The experimental conditions for determination of Au by gravimetry were listed as below: 2 g of gold-platinum waste liquid was extracted for three times with total 30 mL of ether to separate Au(Ⅲ); then Au(Ⅲ) was reduced with 2.4-3.2 g of ammonium oxalate for 40 min followed by drying at 105 ℃ for 55 min. The experimental conditions for determination of Pt were listed as below: 0.15 g of gold-platinum waste liquid was extracted twice with total 8 mL of ether to separate Au(Ⅲ); then the content of Pt was determined by ICP-AES in the medium of 10% hydrochloric acid. The contents of Au in range of 84%-89% (mass fraction, similarly hereinafter) and Pt in range of 0.5%-5% in gold-platinum waste liquid were determined according to the proposed method. The relative standard deviations (RSDs, n=11) of determination results were 0.030%-0.036% for Au and 0.12%-0.30% for Pt. The recoveries of Au and Pt were 99.88%-100.19% and 99.45%-100.36%, respectively.