EDTA滴定法测定新型复合脱氧剂中的CaC2和CaF2

利用碳化钙易溶解于稀醋酸,而氟化钙不溶解于稀醋酸的特性,以稀醋酸处理试样,用滤纸过滤不溶物后,滤液加氢氧化钾溶液调节pH值≥13,用EDTA滴定法测定CaC2含量。不溶物连同滤纸放在铂金坩锅中灰化、灼烧,加含有硼酸的混合熔剂,于950℃左右熔融,酸化浸取后,加氢氧化钾溶液调节试液至pH值≥13,用EDTA滴定法测定CaF2含量。测定结果表明,CaC2RSD为0.0645%～0.1016%,CaF2RSD为0.6285%～0.8357%。

Determination of CaC2 and CaF2 in New Type Complex Deoxidizer by EDTA Titration Method

Based on the specific property that CaC2 can dissolve in diluted acetic acid while CaF2 can’t dissolve in acetic acid, the sample was treated by acetic acid and the insoluble substance was filtered by filter paper. The filtrate was added with potash solution until the pH value reached 13 （or greater than 13）, and the content of CaC2 was measured by the EDTA titration method. The filtered insoluble substance and the filter paper were incinerated and burned in platinum crucible, and then added mixed flux with boric acid into them. After melting at 950 ℃ around and extracting with acidification, it was added with potash solution until the pH value reaches 13 （or greater than 13）, then the content of CaF2 was measured by the EDTA titration method. The RSD of CaC2 was between 0.0645% and 0.1016% and CaF2 RSD was between 0.6285% and 0.8357%.