GB571751A - An improved manufacture of refractories - Google Patents

Abstract

A refractory composition for furnace linings comprises a ground magnesian clinker and a small amount of a gel-forming plastic hydrous magnesium silicate, e.g. the material known as "Hectorite," found near Hector, California. Up to 6 per cent of the normal commercial product, which includes calcite and other impurities, may be added, but 0.3 to 1 per cent is generally sufficient to impart satisfactory plasticity; for addition to refractory mortars, 1 to 2 per cent may be added. The clinker may contain stabilizers such as boric oxide, chrome ore, or a phosphate to prevent inversion of any dicalcium silicate which may be present, and to prevent hydration, may contain 3 to 4 per cent mill scale, iron oxide or chrome ore, and be dead burnt. The silicate is dispersed through the ground clinker, and is gelled by the addition of water. According to examples: (a) a mortar is made from 94 per cent clinker prepared from dolomite, magnesite and chrome ore by burning at 3000 DEG F. or higher, 3 per cent mill scale, 2 per cent sodium nitrate, all ground to pass a 100-mesh screen, and 1 per cent "Hectorite" ground to pass a 200-mesh screen; (b) a refractory to be used for lining a tap-hole is made by mixing 40 per cent clinker passing 4-mesh, 20 per cent clinker passing 15-mesh, and 31.5 per cent clinker passing 200-mesh, 5 per cent water-soluble sodium silicate, 2 per cent sodium carbonate, 1 per cent trisodium phosphate and 1.5 per cent "Hectorite," the mixture being tempered with about 7.5 per cent water.