Refractory Shapes Information
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Refractory shapes include precast cement and fused or sintered refractory products that are formed prior to installation in furnaces, boilers or other high temperature equipment. Refractories are hard, heat-resistant materials and products such as alumina, silicon carbide, fire clay, bricks, precast shapes, cement or monolithics and ceramic kiln furniture. Ceramics and refractories have high melting points are suitable for applications requiring wear resistance, high temperature strength, electrical or thermal insulation or other specialized characteristics. Some examples of precast refractory shapes include bricks, catalyst supports, checker walls, degassers, furnace liners, nozzles and spargers.
Types of Refractory Shapes
Refractory bricks, blocks, and tiles are refractory shapes that are stacked to form insulating furnaces, boilers or other thermal process vessel walls. Typically, refractory bricks are cemented together with refractory mortar. Refractory shapes also include catalyst supports, which often consist of porous structures with large surface areas, or honeycomb structures that hold a metal catalyst providing easy exposure to a stream of reactive gases or other reactants.
Checker walls or checker brick walls are refractory shapes used in sulfur recovery units or reactors such as Claus reactors. Claus reactors combust corrosive hydrogen sulfide or sour gas (refining by-product) in order to produce sulfur. As refractory shapes, checker walls have become more common than choke rings because they produce better gas mixing, which increases the reaction rate and efficiency. Some styles of check walls are designed with an integral manway for maintenance. The integral manway can eliminate the need to tear down a wall to access, inspect or repair tubes or other vessel components.
Refractory shapes that are used as degassers are used to remove detrimental gases like hydrogen that would induce porosity and reduce strength. Static degassing devices use a porous ceramic to remove harmful gases or impurities through the emission of reactive gas bubbles into the melt. Rotary degassers spin rapidly in the melt causing a shearing effect that breaks up gas pockets into small bubbles for removal. As refractory shapes, degassers may use a combination of gas emission and rotary techniques to degas a melt.
Furnace liners are modular refractory shapes consisting of a series of interlocking components that fit or stack together to form a protective furnace lining. Induction furnaces often utilize a modular furnace lining system fabricated from ceramics that do not interfere with the inductive heating process. Liners may use a backup of ramming cement behind the liner, but not within the interlocking grooves. The absence of refractory cement between the ceramic sections improves the lining life and melt quality of these refractory shapes. Tongue and groove crucibles are a modular crucible system consisting of a series of interlocking components that stack together to form a melt furnace lining or crucible.
Pouring nozzles or orifices are refractory shapes that are used to direct or meter the flow of molten metal or other melted materials. Atomization nozzles are a critical component in the gas atomization process used to product metal powders. Ceramic nozzles are also used to shield other components of a system from arcs or abrasive jet/blast streams. Pouring cups, pouring tubes, tundish nozzles, continuous casting tips also fit into this category of refractory shapes.
Spargers or diffusers are porous ceramic refractory shapes that are used to blow fine bubbles of a gas into a metal melt to remove impurities, particulates or other detrimental melt gases, de-oxidize melts and enable chemical reactions. Others forms of refractory shapes include beams, columns, crucibles, bar stock, round stock, kiln furniture, plates, rods, filters diffusers, and tube stock or cylinders.