高锰酸钾滴定法测定硫酸氧钒干基

摘要

The drying conditions for VOSO4 were obtained by thermogravimetry (Tg) differential scanning calorimetry (DSC), i.e., the drying temperature was 300 ℃ and the vacuum drying time was 70 min.Under this drying condition, the crystal water in VOSO4 could be completely removed to prepare dried VOSO4 sample.The content of V (Ⅵ) in dried VOSO4 was determined by potassium permanganate titration in 7.5%~10% (V/V) sulfuric acid medium.Then, the dry basis content of VOSO4 could be obtained by conversion.The proposed method was applied to the determination of VOSO4 dry basis content, and the relative standard deviation (RSD, n=11) was 0.16%.The VOSO4 dry basis content in certified reference material (the mass fraction of VOSO4 dry basis content was higher than 99.5%) was determined according to the experimental method, and the found value was 99.86%.%通过对硫酸氧钒的热重和差热分析,确定了硫酸氧钒的干燥条件,即干燥温度为 300 ℃,真空干燥时间为70 min.在此干燥条件下,可使硫酸氧钒完全失掉结晶水,得到干燥的硫酸氧钒样品.在7.5%~10%(V/V)硫酸介质中,采用高锰酸钾滴定法测定干燥的硫酸氧钒中钒(Ⅵ)含量,经换算得到硫酸氧钒干基.方法用于硫酸氧钒干基的测定,结果的相对标准偏差(RSD,n=11)为0.16%,按照实验方法测定基准硫酸氧钒干基(硫酸氧钒干基质量分数大于99.5%),测定值为99.86%.