溶剂萃取法准确测定硫酸镍溶液中的微量硅

Determination of Trace Silicon in Nickel Sulfate Solution by Solvent Extraction

探索出了用异戊醇萃取硫酸镍溶液中形成的硅钼蓝、然后用弱碱性溶液进行反萃、最后用分光光度法对反萃液进行测定的一种新方法.实验结果显示,在硅浓度为1～20μg/mL的范围内符合比尔定律,所测的吸收光度值与硫酸镍溶液中的硅含量有很好的线性关系,相对误差3.6%,测量结果准确、迅速、可靠.此方法还可以推广应用于其他有色溶液中微量硅的测定.

For producing high-purity nickel material, silicon is one of the main impurities. To determine the trace silicon content is an exigent problem in industrial production. Test of heteromolybdate blue is the most popular method to analyze the silicon content, but for nickel sulfate solution, this method is limited because of color interference by Ni2+ ions. In this paper, the best conditions for the formation and extraction of heteromolybdate blue were studied. Iso-amyl alcohol was used as the extractant with a pH about 0.5 to extract heteromolybdate blue from nickel sulfate solution. Alkaline solution with pH over 12 was used as the stripping agent. Spectrophotometry was used to determine its absorbency after stripping. The experimental results showed that the absorbency had a good linear relation with the Si content. The analytic results are proved to be accurate, rapid and credible. The new analytical method can also expand to the silicon analysis of other colored solutions.