Patent ID: 7238231
Filing Date: 2007-07-03
Classification: C01G,C01P,C09C

Abstract:
1. A process for manufacturing zirconia-treated titanium dioxide, comprising the steps of: a) forming a mixture comprising a titanium dioxide material in water; b) wet milling said mixture; c) after step b), optionally depositing on said wet milled titanium dioxide material one or more inorganic oxides selected from the group consisting of the oxides of aluminum, boron, cerium, phosphorus, silicon, tin, titanium and zirconium; d) achieving a pH of the mixture resulting from steps b) or c) between about 5 and about 9, whereby the titanium dioxide material is sufficiently flocculated to be recovered by vacuum or pressure filtration; e) removing said titanium dioxide material from said mixture by vacuum or pressure filtration; f) washing the titanium dioxide material recovered by filtration; g) converting the washed titanium dioxide material to a fluid dispersion by addition of one or more alkaline water-soluble zirconium reagents selected from the group consisting of ammonium zirconyl carbonate, the water-soluble ammonium zirconyl carboxylates and mixtures of these; h) drying the dispersion to yield a dry zirconia surface treated titanium dioxide powder.