Abstract: For the purpose of increasing the titanium leaching rate，the titanium in ilmenite was firstly transformed into titanyl sulfate，which was easy to dissolve in dilute acid，by the sulfate melting reaction method，with the ilmenite from Wanning， Hainan Province and（NH₄）₂SO₄ as the main raw materials，and then leaching with dilute sulfuric acid.Effects of the added amounts of（NH₄）₂SO₄  and K₂S₂O₇，reaction temperature，and leaching concentration of dilute sulfuric acid on the titanium leaching rate were investigated.Experimental results showed that the added amounts of（NH₄）₂SO₄ and K₂S₂O₇， and the reac- tion temperature had a greater impact on the titanium leaching rate.The optimum conditions of enhancing the titanium leaching rate were as follows: the mass ratio of ilmenite，（NH₄）₂SO₄，and K₂S₂O₇was 1∶6∶0.5，the reaction temperature was  450 ℃， the holding time was 30 min，and the concentration of dilute sulfuric acid was 2.32 mol/L.The leaching rate of titanium reached 96.82% under the above optimum conditions.

Key words: ilmenite, titanium dioxide, ammonium sulfate, leaching rate