The determination of nickel with dimethylglyoxime in iron and steel containing cobalt and copper

Abstract

The separation of nickel from cobalt and copper with dimethylglyoxime in solutions containing iron has been examined. A double precipitation is always required in test solutions containing more than 3 to 5 mg of copper. Errors owing to the formation of a soluble nickel(IV) compound occur when the reagent solution is added to solutions with a pH above about 4.

For the determination of nickel in samples with up to 10 mg of cobalt in the test solution, precipitation in weakly acid solution is recommended. For the separation from cobalt in high cobalt samples, method A of the British Standard 1121 : Part 37 : 1961 is accurate, provided that unprecipitated nickel(IV) in the filtrate is recovered by extraction and determined separately.