PROCESS FOR THE PREPARATION OF TITANIUM DIOXIDE

摘要

Titanium dioxide is produced by discontinuous digestion of titanium-containing raw materials with sulphuric acid, preparation of a titanyl sulphate solution suitable for hydrolysis from the solid digestion cake obtained in the digestion, hydrolysis of the titanyl sulphate, separation and calcination of the titanium-containing hydrolysis product, evaporation of the dilute acid separated from the hydrolysis product and re-use of the sulphuric acid, separated off from the evaporated dilute acid, in the digestion of titanium raw material, by using the recycled sulphuric acid and, for compensating the losses of sulphuric acid, oleum at such concentrations and in such quantities that the solids-free and salt-free sulphuric acid at the start of the digestion reaction has a concentration of 84-90 % by weight of H2SO4.