Abstract: The present invention is intended to provide a heat-insulating refractory material, which does not contain environmentally and hygienically undesirable ceramic heat-insulating fibers, but only contains organic fibers to the extent necessary to improve adhesive rate upon spraying, and which can nevertheless achieve a specified heat-insulating effect. The heat-insulating refractory material includes a mixture containing 2-50 wt % of a foaming raw material foamed by heat at a temperature from 400.degree. to 1500.degree. C. and 50-98 wt % of a refractory powder, and a liquid binder which is added to the mixture in an amount of 20-250 wt % on the basis of the weight of the mixture.

Abstract: Disclosed herein are a refractory material of high-purity electrofused magnesia clinker having good resistance to corrosion by slag, especially the slag with a high iron content, at high temperatures under an oxidative environment, and a burned or unburned refractory brick made of such refractory material of high corrosion resistance, which is superior in corrosion resistance as well as spalling resistance.The refractory material comprises more than 10 wt. % of electrofused magnesia clinker containing 98.0 to 99.8 wt. % of MgO, less than 0.05 wt. % of SiO.sub.2, and 0.1 to 2.0 wt. % of CaO. It may be in the form of burned or unburned or prepared unshaped refractories.

Abstract: The application by spraying on a ceramic furnace wall of a refractory spray material prepared by mixing a spray powder consisting of 100 pts. wt. a refractory aggregate of a predetermined particle size and 0.1-3 pts. wt. a curing accelerator with 0.5-5 pts. wt. a damping agent added thereto is accomplished with notably high levels of adhesiveness and uniformity without deteriorating the working environment with dust by a method which comprises performing said application while admixing the refractory spray material with a sodium silicate solution as a binder having a viscosity in the range of 3-10 cPs at 15.degree. C. and containing 2-8 wt. % Na.sub.2 O and 8-20 wt. % SiO.sub.2.