Potentiotitrimetric Determination of Aluminum, Iron and Titanium in Bauxite

The fusion of bauxite sample was prepared in nickel crucibles at 720℃ with sodium hydroxide and sodium peroxide as mixed flux, and extracted with water-HCl (by volume ratio of 1 to 1). The total content of aluminum, iron and titanium in the above solution obtained was determined by back potentiometric titration using EDTA standard solution as titrant based on the complexation reaction. Then the contents of iron and titanium were determined by potentiometric titration using potassium bichromate standard solution as titrant based on the redox reaction. Based on the above results, the content of aluminum was figured out. Values of detection limit were found 1.00%, 0.50%, 0.50%. Values of RSDs (n=10) of determination for Al₂O₃, Fe₂O₃ and TiO₂ were kept in ranges of 0.25%-0.32%, 0.69%-4.0%, 1.1%-2.2%, and relative deviation were kept in ranges of 0.24%-0.35%, 0.62%-3.41%, 0.89%-1.81%, respectively. The error caused by artificial endpoint determination in the proposed method was reduced, and the analysis procedure was simplified and the working efficiency was improved.