Effects of inorganic salt on ceramic membrane microfiltration of titanium dioxide suspension

Effects of inorganic salts on ceramic membrane microfiltration of TiO2 suspension were studied for the recovery and separation of titanium dioxide in the production of titanium pigment by the sulfuric acid route. A series of crossflow microfiltration experiments were carried out at various pH values, ionic strengths and with various multivalent inorganic salts. Filtration behaviors were analyzed based on measurements of particle size distribution of the TiO2 suspension, zeta potentials of the ceramic membrane and TiO2 particle. Results showed that inorganic salts affect the microfiltration of TiO2 suspension by changing the surface properties of both the ceramic membrane and TiO2 particle. The solution environments affect the dispersion of TiO2 particles and played a major role in the filtration flux. When the particles were well dispersed, changes in the surface charge of the ceramic membranes become important.