METHOD OF PRODUCING GYPSUM BINDER FROM GYPSUM-CONTAINING SLURRY Russian patent published in 2019 - IPC C01F11/46 

FIELD: technological processes.

SUBSTANCE: invention relates to production of high-quality gypsum binder from gypsum-containing slurries obtained during neutralization of sewage water of machine building and similar enterprises suitable for obtaining different composition of construction materials and articles based thereon. Described is a method of producing gypsum binder from gypsum-containing slurry, involving mixing and processing wastes from: gypsum-containing slurry, hydrolysis sulfuric acid, spent hydrochloric acid etching solution and dolomite flue dust, which is carried out in three steps: at first step, gypsum-containing slurry is mixed with hydrolyzed sulfuric acid to pH equal to 7…8 at temperature of 70…80 °C, at the second step, a hydrochloric acid solution of metal etching and dolomite flue dust are mixed to pH equal to 7…8 at temperature of 70…80 °C, prepared suspensions are thoroughly stirred, mixture of suspensions is transferred to third stage in drier of "boiling bed", in which at temperature of 150–320 °C mixture is dried and simultaneously milled to particle size 10…15 mcm and obtaining a gypsum binder with an admixture of bischofite and iron oxide pigments of brown, black or red colors in accordance with the drying temperature, wherein the quantitative ratio of wastes for processing is, wt%: gypsum-containing slurry 45–50, hydrolytic sulfuric acid 30–35, spent hydrochloric acid etching solution 12–14, dolomite dust of entrapment 6–8.

EFFECT: high strength and water-resistance of the gypsum binder.

1 cl, 2 tbl, 1 dwg, 3 ex