Improving Experiment of the Determination of Total Iron in Iron Ore by Potassium Dichromate Titration Method

The sample was dissolved with sulfuric-phosphoric mixed acid,adding hydrochloride acid to convert the iron to FeCl3,adding SnCl2 to convert most of the Fe3+ to Fe2+,adding excess TiCl3 to convert the remnant Fe3+ to Fe2+,the excess TiCl3 was oxidized by O2 dissolved in solution with copper sulfate as catalyst to eliminate its effect to the accuracy.In the sulfuric-phosphoric mixed acid,the total Fe content was titrated by potassium dichromate standard solution with sodium diphenylamine sulfonate as indicator and the results are satisfactory.