Carbonaceous products are another kind of neutral refractories. According to the composition of the carbon containing raw materials and the mineral composition of the products, it is divided into three types: carbon bricks, graphite products and carbonized siliceous products. The carbon brick is fired by using high-grade petroleum coke as raw material, tar and bitumen as adhesive, and air separation at 1300 C. Graphite products (except natural graphite) were made of carbon materials in an electric furnace at 2500~2800 degree graphitization. Silicon carbide products are made of silicon carbide as raw material, and clay, silicon oxide and other binders are sintered at 1350~1400 degrees. Silicon carbide and silicon powder can also be made into silicon nitride silicon carbide products under nitrogen atmosphere in an electric furnace.