Refractory Cement - Composition, Installation, Use

Refractory cement, a versatile composite of various mixtures such as fireclay, silica, and ganister, or combinations like fireclay with crushed brick, is a specialized material designed to withstand high temperatures. This refractory cement is formed by bonding a bulk refractory grain mass with a fired bond, often incorporating elements like Si3N4 and/or Si2ON2. This unique composition shields the cement from erosion when employed as a liner for furnace walls and troughs. Understanding its formulation, materials involved, and applications unveil the significance of refractory cement in high-temperature industrial settings.

What is Refractory Cement?

Any proportion of mixtures such as fireclay-silica-ganister mixture or fireclay mixed with crushed brick or fireclay–silica sand is known as refractory cement.^[2]

In Refractory cement, a bulk refractory grain mass is initially bonded with a fired bond, which is fired with reaction component Si₃N₄ and/or Si₂ON₂ which protects the ultimate high-temperature sintered cement from the effect of erosion at the time of using the cement as a liner for furnace walls, troughs.

Standard

ASTM E136-79 flammability test.

Materials Consisting of Refractory Cement ^[3][6]

• Calcareous Materials.
• Aluminous Materials (mainly Al₂O₃).
• Magnesium Chloride/Calcium Chloride/Barium Chloride/Sodium Chloride.
• A mixture of binder or clinker and coarse aggregate: Clinker is a fused mineral or mineral mixture used as alumina-lime (bauxite-lime), crushed into a fine powder. It is obtained from aluminous materials. Coarse aggregates are like granular materials that impart some special properties, for example, refractoriness and erosion or oxidation resistance. 
• Alumina ceramics, fire clay, bricks, precast shapes, aluminate cement, and monolithic. 
• Asbestos.  
• Burned spinel. 
• Magnesia.  
• Reactive magnesia. 
• Organic acid.

To produce cement from those components mixture, calcination is done at a temperature within the range of 1,500 to 1,550 C. ^[7]

Applications of Refractory Cement ^[8][10]

Refractory cement is mixed with refractory aggregates such as:

• Bauxite.
• Tabular alumina.
• White Fused Alumina. 
• Brown Fused Alumina.  
• Andalusite. 
• Sillimanite. 
• Chamotte. 
• Alag. 
• Perlite. 
• Vermiculite. 
• Bubble alumina.

Refractory cement can be used in various places. Example:

• In fireplaces and Wood burning stoves where the temperature is very high refractory cement can be used.
• Refractory cement is a good material to patch Furnaces and Incinerators.  
• At the time of Setting and bonding firebrick in firebox chambers, it can play a good character. 
• Electrical or thermal insulation. For providing thermal insulation from any type of heat it can do a better role.  
• To seal air and gas leaking refractory cement acts well.

Installation Technique of Refractory Cement ^[4][5]

1. Vibration Casting
2. Pump Casting. 
3. Dry Gunning. 
4. Wet Gunning or Shotcrete. 
5. Self-flow Casting.

Exception From normal Formula ^[1]

Refractory properties of cement can be imparted to it from non-refractory CaSO₄. This can be done by incorporating a primary fluxing component. This exception can be used as a Structural board, for forming a refractory mass and as oil well casing cement.