硫酸挥发除硒-火试金法连续测定粗硒中金量和银量

Continuous Determination of Gold and Silver in Crude Selenium Using a Process of Selenium Removal by Heating Sulfuric Acid Followed by Fire Assay

针对粗硒样品中金银测定时硒的干扰问题,采用硫酸冒烟挥发除硒,冷却加水后,加入氯化钠溶液沉淀银,过滤后残渣采用火试金重量法测定金量和银量,建立了硫酸挥发除硒-火试金重量法连续测定粗硒中金量和银量的方法,探讨了残余硒量、硫酸用量、加热时间等因素对测定结果的影响,并对比了连续法与行业标准方法测定粗硒中金量、银量结果。连续法测定的金相对标准偏差RSD7为0.54%~1.30%,银相对标准偏差RSD7为0.28%~0.39%,金加标回收率为94.6%~101.3%,银加标回收率为96.3%~100.1%,测定结果与行业标准方法一致。此方法分析速度快,具有较好的精密度和准确度,适用于粗硒中金、银含量的测定。

In view of interference of the existence of selenium in determination of gold and silver in crude selenium sample,the sample with an addition of concentrated sulfuric acid was firstly heated to remove selenium.Then,sodium chloride solution was added to precipitate silver therein,and the obtained residue after filtration was taken for gold and silver determination using fire assay by gravimetry.Thus,a process of heating with sulfuric acid to remove selenium followed by fire assay gravimetry was established for continuous determination of gold and silver in crude selenium,and the effects of residual selenium,sulfuric acid dosage and heating time on the determination results were also discussed.Furthermore,such continuous determination process was also compared to the industrial standard method in terms of the analysis of gold and silver in crude selenium.By using the proposed continuous method,the relative standard deviations(RSD7)of gold was within a range of 0.54%-1.30%,and the RSD7 of silver was within a range of 0.28%-0.39%.The spike recovery of gold was 94.6%-101.3%,and the spike recovery of silver was 96.3%-100.1%.It is shown that the analysis results are consistent with those by industrial standard method.It is concluded that the proposed determination method,being fast and accurate,is suitable for determination of gold and silver in crude selenium.