注入热焓法测定萃取磷酸中三氧化硫

Determination of Sulphur Trioxide in Extracted Phosphoric Acid by Injection Enthalpimetric Method

以钡离子与硫酸根离子沉淀反应的热效应为基础，通过测定孤立体系中的温度变 化，建立了测定萃取磷酸中三氧化硫的注入热焓法。该法在 ４．０～３２．０ ｇ／Ｌ范围内可准确测 定ＳＯ３的含量，相对标准偏差为１．８％；标准加入回收率为９８％～１０３％。

An injection enthalpimetric method for the determination of SO3, has been devel- oped based on measuring the change of temperature in the isolated system during the exothermic reaction of Ba2+ and SO2-4. The concentration of SO3 may be determined in the range of 4. 0~32. 0 g/L with RSD of 1. 8% and recovery of 98%~103%.