What is refractory or high alumina cement?
In refractory cement, which is also called peraluminum cement, alumina lime compounds are considered its main component. In terms of chemical composition, this cement includes a combination of calcium oxide with silicon oxide, aluminum oxide, iron oxide, etc.
Refractory cement hardens when mixed with water and close to air and its resistance increases. The reason for this is calcium aluminosilicate in cement, which creates calcium aluminate hydrates after combining with water and strengthens the hardening ability of cement.
Refractory cement is added in very small amounts to adhesives such as Portland cement to increase its setting speed. The color of this cement comes from the iron oxide in it. If the amount of iron oxide in cement is high, its color is brown to dark gray, and if its amount is low, the color of cement is from brown to light gray.
What are the characteristics of refractory cement?
Refractory cement has excellent features that make this cement very different from other cements. These features include:
The setting time of this cement is the same as ordinary Portland cement, but it hardens sooner.
Refractory cement concrete maintains its mechanical strength at high temperatures and is resistant to thermal shock.
Refractory cement has a very high resistance to corrosive substances such as acidic and sulfated waters and sea water.
Concrete that is made of refractory cement has a very high strength against wear and impact, that’s why it is used for the flooring of industrial halls.
What are the production steps of peraluminum cement?
To produce this type of cement, limestone is combined with an equal amount of bauxite, then materials containing iron and silica are added to it and the resulting mixture is heated in a furnace. In this case, all the melted raw materials are removed from the furnace and poured into a tray and cooled. These materials, which are cooled in the form of glass sheets, enter the crushing machine and are turned into small pieces called clinker. Then the clinker goes to the mill and is powdered. The result of this process is high alumina cement which has a dark color.
What is refractory cement concrete?
The concrete made from this cement has fireproof properties according to the type of concrete aggregates and the cement composition. Refractory cement does not create calcium hydroxide when it hardens, that’s why it shows resistance up to 1900 degrees Celsius. If concrete is used at low temperature, the amount of fireproof cement used is almost high and about 30% by weight, but if concrete is used for high temperature, the amount of cement is less and about 10% by weight.
What is the use of refractory cement?
The use of Nesor cement is very wide and diverse, for example, this type of cement is used as an excellent adhesive to strengthen bricks due to its thermodynamic properties. Some of the functions of this cement include:
Waste incinerator equipment
Construction of chimneys
Construction of furnace floor and wall
Construction of intermittent and tunnel furnaces
Dryer and preheater of cement kilns
