Rare earth and alkali sulfides, process for their preparation and their use as coloring pigments

摘要

The present invention provides rare earth and alkali sulfides, a process for their preparation and their use as pigments. The expression of this sulphide is ABS₂(Where A is at least one alkali and B is at least one rare earth) and consists of fine particles having an average size of less than or equal to 1.5 m. The process for preparing the sulfide includes the steps of exposing one or more rare earth carbonates or hydroxycarbonates to one or more alkali element compounds followed by heating them in the presence of at least one gas selected from hydrogen sulphide or carbon sulphide, Including coagulation at random. The sulfide may be used as a pigment in a material made from a material comprising at least one inorganic binder or at least one inorganic binder, such as plastic, paint, surface coating, rubber, ceramic, glaze, paper, ink, cosmetic, dye, Can be.