Improvements in or relating to the Production of Zinc Pigments or Mixtures containing Zinc Sulphide

575. StucklÚ, H. W. de. Jan. 9. Weatherproof paints; paints, materials for.- Mixed paints containing precipitated sulphide of zinc are rendered light and weatherproof by partly removing the hydrate water, the best results being obtained when there are at least five molecules of zinc sulphide for one molecule of water. In the case of mixed paints obtained by simultaneous precipitation, it is necessary that precipitation be effected from alkaline lyes. As an example, precipitated zinc sulphide with an admixture is heated to 300‹ C. until the desired product is obtained. Or a mixed solution of sodium zincate and sodium sulphate is precipitated with barium sulphide, and the mixed precipitate dried, and heated as before. The drying may be effected at various temperatures, and in a vacuum.