| abstract |
A process for coating a solid, water-insoluble particulate matter with a metal oxide comprising: (a) contacting the solid, water-insoluble particulate matter with an ionic additive and an aqueous medium to obtain a dispersion of said matter particulate with positive charges on its surface; (b) subjecting the particulate matter to a coating process which comprises precipitating a metal oxide salt on the surface of the particulate matter to form a metal oxide layer thereon to thereby obtain the particulate matter coated by a metal oxide coating layer; (c) repeating step (b) at least 4 more times; and (d) curing said coating layer; wherein said curing is not carried out between repeated coating stages, but only at the end of the process. |