Experimental Study on Acid Leaching Purification of Titanium Gypsum

The physicochemical properties of titanium gypsum were analyzed and a single factor experimental study on acid leaching purification was carried out.The effects of liquid-solid ratio,leaching time,concentration of leaching solution,leaching temperature and system pressure on the purification of titanium gypsum were studied.The results show that the optimum reaction conditions under normal pressure is determined as the following:liquid-solid ratio of 4,leaching time of 45 min,concentration of leaching solution at 15%,and leaching temperature of 65 ℃,and the removal rate of iron,aluminum,and magnesium is about 85%,56% and 91%,respectively.When the pressure of the reaction system increases to 2.0 MPa,the removal rate is further improved.It is found by analyzing the mineral micro-morphology,that the crystal form of calcium sulfate in the titanium gypsum after purification is not changed significantly,and that the iron hydroxide attached to the surface of the calcium sulfate crystal is removed effectively.Meanwhile,the content of iron,aluminum,and magnesium in titanium gypsum is decreased significantly after pressurized purification.