Simultaneous determination of cobalt and nickel in cobalt concentrate by multi-wavelength spectrophotometry

The color reaction conditions of Co? and Ni? with xylenol orange in pH 7.8 solution are researched.A K-matrix spectrophotometry for simultaneous determination of cobalt and nickel is established. The apparent molar absorptivity of complex is 2.42×10~6 L·mol~(-1)·cm~(-1) for cobalt and 1.63×10~5(L·mol~(-1))·cm~(-1) for nickel,and the relative standard deviations are 4.8% and 3.9%,respectively.The average addition recoveries are 110.0% for cobalt and 94.1% for nickel.This method has been used for the determination of cobalt and nickel in synthetic samples and cobalt concentrate.