EDTA滴定法测定矿石中铅含量的方法改进

对以往测定铅的方法进行了改进。消解样品的体系为盐酸-硝酸-硫酸和氟化铵,氟化铵(200 g/L)的加入量为3 mL；硫酸加入量为10 mL,浓度为1+1；硫酸铅沉淀静止时间为45 min；除去铋干扰的方法为调节溶液的pH值用EDTA溶液进行分步滴定；将过滤后的滤液进行回收测定,与滴定的结果相加以得到最终结果,滤液中铅含量的大概范围为0.13 %~0.27 %。本方法的精密度为0.12%~0.15% ,准确度为0.24%~0.43%。

An Improved Method for Determination of Lead in Ores by EDTA Titration

s The previous methods for the determination of lead were improved. The digestion system of the sample was hydrochloric acid, nitric acid, sulfuric acid and ammonium fluoride. The addition amount of ammonium fluoride (200 g/L) was 3 mL.Sulfuric acid was added in 10 mL and the concentration was 1+1.The rest time of lead sulfate precipitation was 45 min.The method to remove the bismuth interference is to adjust the pH value of the solution and use EDTA solution for distribution titration.The filtrate after filtration was recovered and measured, and the final result was obtained by titration. The lead content in the filtrate ranged from 0.13% to 0.27%.The precision of this method is 0.12%~0.15% and the accuracy is 0.24%~0.43%.