Fireclay Brick
Fireclay brick is also called chamotte brick. It is acidic firebrick. The higher SiO2 content, the stronger acid corrosion resistance. Fireclay brick has certain degree of acid slag corrosion resistance, but its alkaline slag corrosion resistance is not good. Therefore, fireclay brick is usually used as acidic kilns inner lining. The main applications of fireclay bricks are blast furnace, hot blast furnace, glass furnace, carbon furnace, etc.
Fireclay Bricks Production Process
Fireclay clinker preparation. Fireclay clinker used to make fireclay brick is calcined in in rotary kiln. Fireclay clinker should have stable chemical composition, low impurity content, good sintering property, 2%~4% water absorption rate, true density above 2.7g/cm3.
Fireclay bricks binders. Binding fireclay is usually used as binding agent. It should have high plasticity, low sintering property and high refractoriness. In actual production, 1%~2% of sulfurous acid paper pulp is usually added into raw material as organic binder.
Fireclay The ratio of chamotte and binding clay is decided by quality requirement, shapes, molding methods, etc. If quality requirement is high, chamotte percent should be above 80%, or even 90%. For special shaped fireclay brick, which should have excellent molding property, binding clay quantity should be 25%~30%, or even 40%. For large fireclay blocks, to avoid sintering shrinkage and to keep good shape, clinker quantity should be increased.
Drying and sintering. For semi dry molded fireclay bricks, if there is drying zone in fireclay sintering kiln, they can be directly loaded into kiln for sintering. For special shaped fireclay brick and large size fireclay brick, they should be dried in air for about one week before loaded into drying kiln. Binding clay will have physiochemical reaction during heating, which can contribute to the sintering of fireclay bricks.
Fireclay Bricks Applications
Fireclay bricks is the most widely used firebricks with the largest output in the world. They are used to build working lining and permanent linings of various kinds of thermal equipment and kilns. For example, fireclay bricks are widely used in blast furnace, hot blast furnace, glass furnace, etc.
Blast furnace fireclay bricks are mainly used at small blast furnace throat, furnace bosh, furnace hearth and furnace bottom, large blast furnace bosh. Blast furnace fireclay bricks have high cold crushing strength, long term furnace load wear resistance, small volume shrinkage at high temperature working condition, so furnace lining integrity can be kept. Besides, blast furnace fireclay brick should have low apparent porosity, low Fe2O3 content, so carbon won’t deposit in pores.
Blast Furnace Fireclay Bricks Physicochemical Index
