以碘-乙醇溶液为催化剂,选择乙二醇作溶剂浸取钢渣中游离氧化镁,采用EDTA滴定法测定其中游离氧化镁的含量。试验中考察了碘-乙醇的最佳用量和K-B混合指示剂的最合适配比。结果表明:催化剂碘-乙醇溶液的添加量达碘与氧化镁的质量比为7.5比1,指示剂中酸性铬蓝K和萘酚绿B的比值为1比1.4时,滴定终点变色明显,滴定结果准确。在钢渣中加入纯氧化镁测定的平均回收率为96.5%,相对标准偏差(n=5)为1.3%。

Using ethanolic solution of iodine as catalyst, the free magnesium oxide (f-MgO) in steel slags was extracted with glycol as solvent and determined by EDTA titration. Optimum values of the amount of iodine-ethanol solution and the ratio of K-B indicator were studied. It was shown that the end point of titration was found to have an obvious color change when the ratio of acid chrome blue K to naphthol green B in the solution was 1∶1.4 and the mass ratio of iodine to MgO was 7.5∶1. Test for recovery was made by addition of pure MgO to steel slag, giving values of average recovery of 96.5% and RSD (n=5) of 1.3%.