FAAS Determination of Cobalt in W-Co Hard Alloy Products

The sample of W-Co hard alloy product was dissolved by heating in a mixture of HNO3 and HF and the F- ion in sample solution was driven out completely and a large amount of W separated by precipitation as tungstic acid. The content of Co in the solution was determined by FAAS using the sub-sensitive line of 241.3 nm as spectral analytical line. Linear relationship between values of absorbance and mass concentration of Co was kept in the range within 70.0 mg·L-1. The proposed method was applied to the determination of Co in samples of hard alloy products, and the results obtained were in consistency with those obtained by the potentiometric method described in GB.