三氯化钛-重铬酸钾滴定法测定镍铁合金中的全铁含量

用盐酸-硝酸混合酸分解试样，以氨水-氯化铵沉淀铁离子，使其与干扰元素分离。用盐酸溶解沉淀，用三氯化钛还原Fe3＋，以二苯胺磺酸钠为指示剂，重铬酸钾标准滴定溶液测定镍铁合金中的全铁含量。实验结果表明，该方法具有良好的精密度，准确度高，能够满足对镍铁合金中全铁含量测定的要求。

Determination of total iron in nickel-iron alloy by titanium trichloride-potassium dichromate titration

Using hydrochloric acid and nitric acid to solubilize samples ,using aqueous ammonia and ammo-nium chloride to precipitate Fe3+ ,Fe3+ can be separated from interference elements .The precipitate can be dissolved by hydrochloric acid ,and titanium trichloride is used to reduce Fe3+ ,then total iron quantity can be determined by potassium dichromate titration .The method with good precision can meet the require-ments of nickel-iron alloy in the determination of total iron.