Determination of chromium in laterite-nickel ore by flame atomic absorption spectrometry

The sample was decomposed with mixed acid of phosphoric acid,sulphuric acid,nitric acid and perchloric acid.Then the content of chromium was determined by flame atomic absorption spectrometry(FAAS).The interference from Fe was erasured using matrix matching method.The interference of common existent elements was eliminated by adding sodium sulphate and ammonium chloride into the solution.The absorbance is linear with chromium concentration in the range of 0.05-10.0 mg/L.The relative standard deviation is less than 0.33%.The recoveries obtained by standard addition method range from 98.4% to 100.4%.This method is simple and accurate.