CUMIFRAC (Silicon Carbide Refractories) are produced from silicon carbide, a raw material synthesized in a resistance-type electric furnace at temperature exceeding 2500°C, through the reaction of silica with carbon. They have a thermal conductivity 10 times that of fireclay refractories, good corrosion and thermal shock resistance, and can be formed into complex shapes. They can withstand attack and flame erosion. This makes CUMIFRAC unusual even among advanced refractories and has given it wide uses.