METHOD OF PRODUCTION ON REFRACTORY ITEMS FOR LINING THE THERMAL UNITS MAINLY IN NON-FERROUS METALLURGY Russian patent published in 2007 - IPC C04B35/66 

FIELD: production of refractory items for lining the thermal units, mainly in metallurgy; production of shaped items working in aggressive media and melts with the use of water glass.

SUBSTANCE: proposed method includes preparation of molding sand by mixing the alumina-containing filler and finely-grained component, molding the items and hardening them by drying at strengthening with water glass. Used as alumina-containing filler is material at content of alumina of 15-70% from the group - chamotte, mullite, corundum of the following fraction composition, mass-%: 0-1 mm , 30-40; 5-10 mm, 60-70; used as finely-grained component is highly concentrated ceramic binder suspension at moisture content of 14-17% obtained by wet grinding of crushed alumina material in alkaline medium till obtaining the following particles: up to 5 mcm, 30-50%; more than 63 mcm, up to 7% followed by stabilization continued for 7-20 h; mixture thus obtained has moisture content of 7.5-8.0% at the following ratio of components, mass-%: filler, 50-60; highly concentrated ceramic binder suspension, 40-50. Prior to mixing, the filler of fraction 0-1 mm is wetted with water in the amount of 0.5-1% of total mass of charge for obtaining molding moisture of mixture of 8.8-9.5%; molding is performed in metal collapsible molds; hardening is effected by drying in molds at temperature of 60-100C continued for 6.5-12.2 h and then after opening the mold sides at temperature of 150-200C for 1.5-5 h and after extraction from molds at temperature of 150-200C for 3.5-4.5 h at strengthening the items with water soda glass at density of 1.0-21.06 kg/cm³ and silicate modulus 2.3-2.7; process is completed by drying at temperature of 150-200C continued for 2.5-5.5 h. Wet grinding may be performed in ball mill at loading at three stages of 100% of water and 70% of alumina-containing material; after reaching temperature of 45-60C - 15-20% of alumina-containing material and loading of water soda glass in the amount of 1% of alumina-containing material at each stage. Alumina-containing material is taken from scrap of items crushed to size of grain not exceeding 10 mm.

EFFECT: improves service characteristics of refractory items working in molten and aggressive media.

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