Carbon brick production process
The production process of carbon brick is roughly similar to other refractory bricks, but carbon must be prevented from oxidizing at high temperatures. Therefore, the firing of raw materials and the firing of products must be carried out in a reducing atmosphere. Anthracite must be roasted before use to remove volatiles, sulfur, and moisture, and improve the volume stability, mechanical strength and oxidation resistance of anthracite. The coke must be dried first to avoid forming difficulties due to excessive moisture content and cracking of the product during the firing process. Asphalt must be melted and dehydrated first, so that its moisture content is less than 0.2%, and the dehydration temperature should be 120-160℃.
Carbon brick ingredients are made of roasted granular anthracite as aggregate, and its particle size depends on the size of the product: large bricks are 8-12 mm, and small bricks are 4-6 mm. The amount of anthracite added is about 60%. The coke is added as a fine powder, and the content of the coke whose particle size is less than 88 microns should reach about 70%. The amount of binder added for blast furnace carbon bricks is usually 15-20%. In order to prevent oxidation, coke powder or coal powder is generally used as a protective filler when bricks are fired. The sintering temperature is 1300~1450℃, the holding time is about 20 hours, and the total sintering time is about 240~420 hours. When it is cooled to 40~60℃, it will exit the kiln. Carbon bricks are discharged out of the kiln at high temperature and are easy to catch fire. Carbon bricks are mainly divided into self-baked carbon bricks for electric furnaces and pre-baked carbon bricks for submerged arc furnaces:
Classification of carbon brick
According to the application, it is divided into pre-baked carbon block, self-baked carbon block, semi-graphite carbon block and graphite carbon block.
Self-baking carbon brick for electric furnace: using high-quality low-ash anthracite, graphitized metallurgical coke and broken graphite as aggregates, coal tar pitch and a small amount of additives as binders, after screening, batching, kneading, pressing, roasting, fine milling, Produced by machining and other processes. Because carbon bricks are used as structural materials on large electric furnaces and have a long service life, we have selected high-quality smokeless electric calcined coal with good heat resistance, high strength, and low ash content to improve the chemical stability of carbon bricks. At a high temperature of 1250 degrees, the baking quality is guaranteed and the excessive secondary shrinkage of the carbon bricks when used in the blast furnace is reduced.
Pre-baked carbon brick for submerged arc furnaces: Carbon for submerged arc furnaces made from calcined anthracite and metallurgical coke as main raw materials for ferrosilicon furnaces, yellow phosphorus furnaces, silicon furnaces, calcium silicon furnaces, etc. as lining and conductive materials Piece.
Cold ramming paste, coarse seam paste, carbon mortar, etc. are used for masonry supporting materials for submerged arc furnaces, which are used as the bottom charcoal ramming layer to fill the gap between the carbon block and the carbon block.
