Mercury-free titration of total iron in iron ore with potassium permanganate after titanium trichloride reduction

The sample was treated with HNO3-HF and dissolved with H2SO4-H3PO4 mixed acid.In HCl medium,Fe3+ was reduced to Fe2+ by tin chloride-titanium trichloride.The total iron in iron ore was titrated by potassium permanganate standard solution with sodium diphenylamine sulfonate as indicator.The optimal analytical conditions were determined.This method has been applied to the determination of total iron in iron ore.The relative standard deviation(RSD) was 0.28 %-1.0 %,and the results were consistent with the certified values.This method could prevent the environment from secondary pollution caused by mercury and chromium in mercury bichloride-potassium dichromate titrimetry.