Particulate titanium dioxide coated product and method of forming titanium dioxide coated particles

A composition of matter according to any preceding claim, wherein said substrate is substantially less valuable or expensive than titania.

A composition of matter according to any preceding claim wherein said coating of titanium dioxide on each particle includes a lowermost transition zone in which titanium dioxide is interspersed into the underlying substrate.

A composition of matter according to any preceding claim further including an outer coating on said titanium dioxide layer of a substance to minimise interaction of the titanium dioxide layer with incident ultraviolet light.

A method of forming particles of titania-coated substrate, including:

• contacting a bed of hydrated particles of an oxide or other suitable compound of a metal other than titanium or of certain non-metal elements with a fluid medium containing flowing titanium tetrachloride, under conditions in which a layer comprising one or more involatile oxychloride or oxide compounds is formed at and below the surface of each of a multiplicity of said particles of said oxide or other suitable compound which thereby provides a substrate for said layer;
• and
• treating said oxychloride or oxide compound or compounds to convert the layer to a titania coating, on the particles.

A method according to any one of claims 10 to 15 wherein said coating of titanium dioxide on each particle includes a lowermost transition zone in which titanium dioxide is interspersed into the underlying substrate.

A method of forming particles having a metal oxide coating on a substrate, including:

• contacting a bed of hydrated particles of an oxide or other suitable compound of a first metal or of certain non-metal elements with a fluid medium containing a halide of a second metal, under conditions in which a layer comprising one or more involatile oxyhalide or oxide compounds of the second metal is formed at and below the surface of each of a multiplicity of said particles of said oxide or other suitable compound which thereby provides a substrate for said layer;
• and
• treating said oxyhalide or oxide compound or compounds to convert the layer to a coating of an oxide of said second metal.