Molybdate corrosion inhibiting pigment and method for preparing same

A method for the manufacture of a substantially non-toxic complex corrosion inhibiting pigment which comprises the steps of (1) dispersing a water-insoluble inert inorganic pigmentary sized solid particulate carrier in an aqueous carrier, (2) further dispersing a quantity of pigmentary sized molybdenum trioxide in said aqueous carrier to effect sufficient dissolution thereof to produce reactively available molybdate ions, (3) adding to said slurry and slurrying therein a metal oxide also in a pigmentary size range selected from the group consisting of zinc oxide, calcium oxide, strontium oxide, barium oxide and mixtures thereof thereby producing corresponding reactive, available metal ions in said aqueous carrier slurry, (4) reacting said metal ions with said molybdate ions to precipitate substantially insoluble metal molybdate compounds as an adherent deposit on said particulated inert carrier, continuing said acid-base type reaction and precipitation of the corresponding metal molybdate reaction products on said inert carrier particles until the reaction is substantially completed, separating the thus formed salt-free complex molybdated pigment product from the gross aqueous salt-free reaction medium, drying and removing substantially all the remaining moisture including water of hydration therefrom.