Red rare-earth lanthanum cerium sulfide dye and preparation method thereof

Abstract

The invention relates to a rare earth lanthanum and cerium sulfate which can be used as a red paint and a preparation method of the rare earth lanthanum and cerium. The chemical formula of the paint is: AxLayCe1-yS(3+x) / 2, wherein, A stands for one of alkali metals lithium, sodium and potassium, x is equal to or bigger tan 0 and is equal to or smaller than 1, and y is equal to or bigger tan 0 and is equal to or smaller than 1. The alkali metal elements are doped into the rare earth lanthanum and cerium sulfate matrix to prepare rare earth sulfide paints in different red color systems through adjusting the doped amount of the alkali metal elements and different proportions of the lanthanum and cerium in high temperature solid-state reaction with mixed sulfate source gas produced by ammonium thiocyanate being heated and melted as reaction gas under the conditions of unoxidizing atmosphere with inert gas being input and the heating temperature of 400 to 1000 DEG C. The structure of a series of rare earth lanthanum and cerium sulfate doped with the alkali metal elements is NaC1type or Th3P4 type of gamma type in single cubic crystal system. The preparation method is safer and more environment protecting, the paint is non-toxic, so that the paint can be used for coloring for plastic, oil paint, coating, rubber, leather, ceramic, ink, paper, cosmetic and construction material like cement.

Description

technical field [0001] The invention relates to a rare earth lanthanum cerium sulfide which can be used as a red pigment and a preparation method thereof. technical background [0002] Pigments can be divided into organic and inorganic pigments. Due to the advantages of good covering ability, good thermal stability, bright color and good dispersion, inorganic pigments have been widely used in many industrial fields, especially in plastics, paints, coatings, etc. , rubber, leather, ceramics, ink, paper, cosmetics, etc. Inorganic coloring pigments widely used at present, such as cadmium red, cadmium yellow, chrome green, because they contain metals that are increasingly restricted and even banned by legislation in many countries (especially cadmium, lead, chromium and cobalt) ). These metals are generally considered to be highly toxic. For example, among the six toxic and hazardous substances restricted by the "RoHS" directive implemented by the European Union on July 1, 20...

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Problems solved by technology

In the above method, if S is used as the sulfur source, sulfur actually boils at about 400 degrees, so the reaction at high temperature is prone to sulfur deficiency, so that the product is easily mixed with sulfur oxides, and the stability of sulfur oxides and color properties are not as good as γ-Ce 2 S

In the above method, if different raw materials are used, for example, the halide product is β-Ce 2 S, the β-type structure is far less good than the γ-type structure in terms of color performance, especially brightness

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