IN264579: A process for the preparation of inorganic pigment based on mixed rare earth oxides

The patent discloses a novel environment-friendly high-temperature pigment of dark red-brown hue based on rare earth oxides containing cerium oxide (40-60 wt percent ), lanthanum oxide ( 10-25 wt percent ), neodymium oxide (5-15 wt percent ), praseodymium oxide( 2- 10 wt percent ), samarium oxide( 2- 10 wt percent ), gadolinium oxide (1 - 5 wt percent ) from raw material, namely, mixed rare earth carbonate, wherein individual carbonate is intimately mixed due to the way of preparation of it. The patent also relates to a novel processing route, namely, thermal plasma processing, wherein the mixed rare earth carbonate is heat treated in a plasma furnace to prepare the pigment. The availability of very high temperature, high energy flux, and plasma state condition in the plasma arc allows the reactions to be completed in a very short duration. Pigment finds extensive applications as glazes and colorants in the Ceramic industry. It also can be used as a colorant in plastics, coatings, and glass enamels.