Fire Clay Refractory Castables

Description:

Fire Clay Refractory Castables (also called Clay-based Refractory Castable), Fireclays are clays that are immune to deformation and melting at high temperatures in the ceramics industry. Unfired refractory bond clay and fireclays (chamotte), fired refractory clay, or similar grog ingredients are used to make fireclay refractory bricks. The basic components of fireclay refractory castables are 18 percent to 44 percent alumina (Al₂O₃) and 50 percent to 80 percent silica (SiO₂).

Fire Clay Refractory Castable is a castable refractory material prepared by using soft clay as a binder and refractory aggregates, powders and admixtures such as aluminum silicate or corundum mullite. The composition of the clay castables is generally 55% to 65% for refractory aggregates, 20% to 30% for refractory powders, and 10% to 15% for combined (soft) clays. The maximum allowable particle size of refractory aggregate is 8mm, and the aggregate size of aggregate is 8~5mm, 35%~40%; 5~3mm, 30%~35%;<3mm, 25%~30%. The particle size requirement of the refractory powder is less than 0.074 mm and accounts for more than 90%. The combined clay particle size should be less than 0.074mm and account for over 95%.

Fireclay refractory castable adding alumina powder material, soft clay binder, according to the proportion of compound mixture mixing more than 5 minutes and the mixer, generally, the using temperature is 1300-1450 ℃. Fire Clay refractory castables are mainly used in the lining of steel rolling heating furnace, heat treatment furnace,boiler, shaft kiln, preheating zone of rotary kiln. Also refractory fire clay castable is widely used in various kinds of kiln lining. such as boiler, blast furnace hot blast stove, heating furnace, ceramic kiln, cement rotary kiln, power plant wall etc.

The main component of refractory fireclay is hydrated aluminum silicates, with tiny amounts of other minerals. Al₂O₃.2 SiO₂.2H₂O is the standard formula for these aluminum silicates, which equals 39.5 percent alumina, 46.5 percent silica, and 14 percent water (H₂O). The most prevalent member of this category is kaolinite. The mixed water is driven off at high temperatures, leaving a residue that is 45.9% alumina and 54.1 percent silica in theory. Even the cleanest clays, however, include trace amounts of other components such as iron, calcium, magnesium, titanium, sodium, potassium, lithium, and free silica. The total amount of these melting point-lowering fluxing agents should be no more than 5% to 6% of the overall amount. TiO₂ is not considered a fluxing agent, however it was previously counted alongside alumina.

Properties

1.       Good plasticity and convenient construction;

2.       High bonding strength and strong corrosion resistance;

3.       High refractoriness, up to 1650℃±50℃;

4.       Good resistance to slag invasion;

5.       Good thermal exfoliation.

Chemical & Physical Index

Characteristics

Fire Clay refractory castable is a high-tech refractory developed on ordinary castables using rheological principles, the closest packing theory and ultra-fine powder technology. It has the characteristics of low porosity, small pore size, large density, good volume stability, high strength and small water addition, and overcomes the characteristics of ordinary castables that the strength decreases significantly at 800 to 1200℃, and increases with the temperature. And increase, so that the thermal shock resistance of the furnace body can be more than doubled.

Packages of castable

Packing: Export Wooden Pallets, Damp-roof bag, 25kgs / bags.

The package is designed to protect castable from humidity. However, as with all hydraulic binders, it is recommended that castable not be placed outdoors or in direct contact with the ground. When correctly stored in dry conditions, the properties of castable will remain within specification limit for at least 9 months. In most cases, its properties will be retained for over a year.

Application

l  In construction concretes, rapid strength development is achieved, even at low temperatures.

l  In construction concretes, high chemical resistance is possible.

l  In refractory concretes, strength is maintained at high temperatures.

l  As a component in blended cement formulations, various properties such as ultra-rapid strength development and controlled expansion can be obtained.

With the development of modern smelting technology, hot blast stoves generally adopt high air temperature technology, and the service life of hot blast stoves is required to be longer: therefore, higher requirements are put forward for the comprehensive performance of refractory materials for hot blast stoves. Damage to refractory materials used in hot blast stoves is usually caused by thermal stress, chemical attack, and mechanical loading. It is generally believed that an important reason for the damage of the hot blast stove is that the high temperature creep resistance of the refractory material is poor, resulting in collapse, deformation and cracking of the lining refractory material, thus causing widespread concern for low creep bricks for hot blast stoves.