Preparation of thermally stable lead chromate pigments

摘要

Thermally stable lead chromate pigments or pigments containing lead chromate, which have high color strength and are provided with a precipitated coating containing silicon dioxide, are prepared by a process in which an aqueous pigment suspension is mixed once or several times with an aqueous MgSiF6 solution, the pH being maintained at 4.5-9.5 and the temperature at 50 DEG -95 DEG C., and the pigment is then separated off and worked up, these steps being carried out in a conventional manner.