EDTA滴定法联合测定硅铁中的铝和钙

Combined Determination of Aluminum and Calcium in Ferrosilicon by EDTA Titration

实验采用EDTA滴定法联合测定硅铁中铝和钙的新方法。在样品溶解并消除干扰元素影响后的试液中，分取部分试液于pH4．5～5的乙酸-乙酸钠缓冲介质中，用氟化铵置换EDTA滴定法测定铝量。在另一份试液中的Fe3＋、A13＋、Mn2＋等元素的干扰，用三乙醇胺掩蔽，少量铜、铅、锌等重金属的干扰用半胱氨酸溶液掩蔽，在Mg“离子存在情况下，于pH≥12．5的碱性介质中，以钙指示剂用EDTA标准溶液滴定法测定钙量。实现了同一个试样母液联合快速测定铝和钙，相对标准偏差铝为1．343％～2．479％，钙为2．460％～8．085％。

New method to jointly determinate Aluminum and Calcium in ferrosilicon by EDTA titration is taken in testing. After the sample is dissolved and the influence of interference elements ~s eliminated, a part of solution is put into pH4.5 ～ 5 acetic acid-sodium acetate buffer solution, the content of alumi- num is titrated by ammonium fluoride EDTA titration. In the other part of solution, the interference of Fes＋, A13 ＋ and Mn2＋ is masked by triethanolamine, the interference of Copper, Lead and Zinc is masked by cysteine solution, and in the alkaline medium with PH ≥ 12.5, with the existence of Mg2 ~ ion, taking a calcium indicator, the content of calcium is titrated by EDTA standard solution. The method realizes the fast combined determination of aluminum and calcium by using the solution of the same sam- ple, its relative standard deviations are 1. 343% ～ 2. 479% for aluminum and 2. 460% ～ 8. 085% for calcium.