Selective determination of sulfuric acid in liquors from acidic nickel ore extraction by flow injection analysis

A two channel flow injection analysis (FIA) system for selective determination of sulfuric acid in liquors from acidic nickel ore extraction has been developed. Absorbance at 520 nm is increased due to changes in the reagent system (sodium sulfate/ methyl orange) caused by reaction with H2SO4 injected. Data processing was performed by non-linear regression. The results obtained by the proposed method are compared with those obtained by traditional potentiometric titrations. The setup allows a sampling rate of 120 samples per hour. The relative standard deviation (RSD) obtained was ≤8%.