论文部分内容阅读
多年来,建立快速、准确的高含量钨的分析方法是国内外分析工作者研究的重要课题。据报道,差示分光光度法,虽然快速,但操作要求严格,且需用精密仪器;络合滴定法和酸碱中和法,则影响因素较多;氧化还原法由于钨的易变价特性,往往难以把它还原或氧化至某一固定价态并保持稳定。本文提出在硫氰酸盐介质下用铅粒或银粉将钨(Ⅵ)定量还原为钨(Ⅴ),然后用标准铁(Ⅲ)溶液滴定钨(Ⅴ)的新方法,由于钨(Ⅴ)酰硫氰酸络合物在空气中很稳定,测定获得良好效果。方法快速、准确、干扰少,用于测定矿物中高含量的钨,结果与硝酸铵重量法一致。
Over the years, the establishment of fast and accurate high-content tungsten analysis method is an important issue for domestic and foreign analysts. According to reports, differential spectrophotometry, although fast, but the operation is demanding, and the need for precision instruments; complexation titration and acid-base neutralization method, the more influencing factors; redox method due to the variable price of tungsten, It is often difficult to restore or oxidize it to a fixed valence and maintain stability. This paper presents a new method for the titration of tungsten (Ⅴ) with standard iron (Ⅲ) solution by reducing lead (Ⅵ) to tungsten (Ⅴ) with lead or silver powder under thiocyanate medium. Thiocyanate complexes in the air is very stable, measured good results. The method is rapid, accurate and has less interference. It is used to determine the high content of tungsten in the minerals. The result is in accordance with the gravimetric method of ammonium nitrate.