Reduction of frerric iron in the titanium sulfate solution by the ion-exchange membrane primary cell method

Abstract

In the production process of titanium dioxide with sulfuric acid, the contamination of the titanium sulfate solution (the ilmenite leaching solution) in the Fe³⁺ reduction stage by iron scraps is a practical problem because it is difficult to guarantee the quality of the iron scraps. In this research, a new method, called the ion-exchange membrane primary cell method, for reduction of Fe³⁺ in the titanium sulfate solution has been advanced. The positive compartment of the primary cell consists of lead (copper) electrode and the titanium sulfate solution, and the negative compartment consists of iron electrode and acidic FeSO₄ solution. The anion ion-exchange membrane is used as the diaphragm between two compartments. Fe³⁺ in the titanium sulfate solution is reduced by the electric discharge of the primary cell. The effects of temperature, stirring strength of the solution and membrane area on the reduction rate have been investigated. The experimental result shows that the optimum current density can be higher than 100 A/m².