Patent ID: 8221834

Claim:
A method of preparing a titania composite, the titania composite comprising an inner core and a coating film layer wherein the inner core is a barium sulfate crystal and/or a strontium sulfate crystal with subsphaeroidal appearance, having a particle size of less than 1 μm and a whiteness of more than 98%, and the coating film layer is nano rutile titania; the method comprising: (a) preparing barium sulfate or strontium sulfate by consecutively reacting barium sulfide or strontium sulfide with excess sulfuric acid by cocurrent flowing to produce barium sulfate or strontium sulfate and hydrogen sulfide, discharging the hydrogen sulfide by degassing, then obtaining a suspension of barium sulfate or strontium sulfate after separating and washing treatment; (b) coating treatment by adding titanium tetrachloride or titanyl sulfate into the suspension of barium sulfate and/or strontium sulfate, wherein an amount of TiO 2 in the titanium tetrachloride or titanyl sulfate is 4% to 35% in a total weight of TiO 2 and barium sulfide and/or strontium sulfide when addition amount of titanium tetrachloride or titanyl sulfate is based on stoichiometric amount of TiO 2 in the titanium tetrachloride or titanyl sulfate; hydrolyzing and coating in a temperature range of 60° C. to 95° C. for 2 to 4 hours, then obtaining a titania composite after separating and washing treatment; (c) subjecting the titania composite to a high-temperature heat treatment by subjecting the titania composite obtained in step (b) to a high-temperature heat treatment in a temperature range of 600° C. to 1200° C. for 50 min to 70 min; and (d) subjecting the titania composite to a post treatment by cooling the titania composite treated after high-temperature heat treatment, crushing and sieving, to obtain a product.