返滴定法测定硬质合金中的铁、镍和钴

利用运滴定法消除镍对二甲酚橙指示剂的封闭作用，在pH5．5～6．0先测得铁、镍和钴的总量，再利用镍、钴在强碱性溶液中有效稳定常数不同及铁可波三乙醇胺掩蔽的特性，用钙盐返滴定法测得镍和钴分量．此方法不需分离，简便、快速，应用于含镍、铁和钴的硬质合金中铁、镍和钴的测定，结果令人满意．

DETERMINATION OF FERRUM,NICKEL AND COBALT IN CEMENTED CARBIDE BY RESIDUAL TITRATION

The total content of Fe. Ni and Co can be deterndned by residual titration in pH 5. 5~6. 0, and in view of the differenceof the effective stability constants of the EDTA complexes of Ni and Co in strong alkaline medium, Ni and Co can be der-endned continuously by residual titration with calcium salt, the interference of Fe can be eliminated by adding tri-etbanolaforne. This methed is simple and fast and has been satisfactorily used for the detendnation of Fe、Ni and Co in ce-mented carbide.