METHOD FOR COMBINED TREATMENT OF CALCIUM-CONTAINING AND SULPHATE-CONTAINING WASTES Russian patent published in 2015 - IPC C01F11/46 C03C3/76 C03C6/04 

FIELD: chemistry.

SUBSTANCE: invention can be used in chemical industry. The method for combined treatment of calcium-containing and sulphate-containing wastes includes alkalising chlorine-containing lime waste gas from gas purification to pH 11-11.5. Gypsum sludge is obtained by mixing the chlorine-lime waste with aqueous solution of sulphate-containing ash - trinitrotoluene production waste. The gypsum sludge is separated by filtering from a filtrate, which is fed for preparation of bleaching solutions. The gypsum sludge is then dried and silicate glass is obtained by melting a mixture based on the calcium-containing component in the form of the gypsum sludge. The mixture for producing silicate glass contains the following components, wt %: quartz sand 41.60; kaolin 4.60; sulphate-containing ash 21.47; gypsum sludge 20.60; dolomite 4.10; portafer (Fe₂O₃) 1.98; chromium (III) oxide 0.25; titanium (IV) oxide 0.76; manganese (IV) oxide 0.01; potassium nitrate 0.46; monosubstituted sodium phosphate 0.04; barium hydroxide 0.04; sulphite liquor (by solid substance) 2.45; birch charcoal 1.64. The mixture is melted at 1350-1400°C.

EFFECT: invention enables to obtain silicate glass via combined treatment and recycling of calcium-containing and sulphate-containing industrial wastes.

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