Abstract: The present invention relates to an anti-corrosive pigment composition, characterized by comprising, as main components, white anti-corrosive pigment and an inorganic anion exchanger represented by the following formula (1):(3-4)[M.sub.1 ]O.Al.sub.2 O.sub.3.[M.sub.2 ]X.sub.2/m .multidot.nH.sub.2 O(1)(wherein, M.sub.1 and M.sub.2 are at least one selected from Ca.sup.2+ or Zn.sup.2+, X represents at least one anion selected from NO.sub.2.sup.-, NO.sub.3.sup.- or MoO.sub.4.sup.2-, m represents a valency of the anion, and n is 20 or less).

Abstract: A stable lead chromate pigment composition comprising a lead chromate pigment which has been treated by forming a continuous amorphous silica encapsulation on the surface of each particle of the pigment and subsequently depositing an antimony compound on the silica encapsulation and the process for producing the same.

Abstract: A process for preparing a stable inorganic pigment coated with a fine amorphous silica which comprises forming a silica sol in an aqueous prepared slurry of an inorganic pigment by reacting an alkali silicate solution with one or more acid gases so that a fine silica sol covers the surfaces of the particles of the inorganic pigment.

Abstract: An antimony trioxide composition useful as an excellent flame retarding additive comprises antimony trioxide particles coated with hydrous zirconium oxide and amorphous silica.The antimony trioxide composition is prepared by adding an aqueous solution of a zirconium salt to an aqueous slurry of antimony trioxide particles to form zirconium hydroxide therein and to deposit the hydroxide on the surfaces of the antimony trioxide particles, recovering the particles and dehydrating them to form a coating of zirconium hydroxide on the particles, dispersing the hydrous zirconium oxide-coated particles in water, and then adding to the resulting aqueous dispersion a silica sol to deposit amorphous silica on the surfaces of the hydrous zirconium oxide coated antimony trioxide particles.