Industrial sector has developed enormously after advancements in the field of engineering. Day by day, engineers all around the world experiment new ways to build materials that can help in the development of industries. Since a major role is played by the industrial sector in bringing stability to the economy of a country, so there is always demand for new and latest technological developments related to industries. Among many of the gifts of engineering given to industrial lobby is refractory. Refractories are materials which are able to keep their strength at extreme temperatures. Usually these materials are non-metallic preferably ceramic so they are able to work at extremely high or low temperatures. Such a material surely brought revolution to the iron and steel industry, not only this, these materials also came out to be furnaces in all those industries where the chemical reactions produce presipetates and by products that are of extreme acidic or basic nature along with high or too low temperature.
Castables Refractories are not only useful in metal industry but also can be utilized by architectural engineers. Refractory castables are almost similar to original castables but they are meant to create refractory concrete materials. The raw materials, which when mixed with water are poured and dried up to form refractory concrete. The raw materials in these castables consists of grinded refractory materials eg fillers, aggregates and additives along with a bonding agent. The most common bonding agent used is high alumina cement (HAC). Another alternate to HAC can be collodial silica. Castables are mixed with water and then poured or fired through air guns. Usually at the nozzle, cement accelerators are added to promote quick hardening. Now a days such shaping machinery is also available which can shape the poured refractory castable into the desired shape.
Castable Refractories are generally preferred for furnace linings and coatings of irregular dimensions, for patching brickwork and for casting specific shapes. The composition of refractory castable depends on type of application and the temperature at which they are to be used. For high temperatures ie 900 oC to 1500 oC provides more strength and abrasion resistance as compared to moderate temperature i-e 500 o C to 1000 o C. However at high temperature high strength ceramic bonds are not formed. It is also noticed that for intermediate temperatures Portland type cements are not capable of being used as bonding agent. Usually chrome ore or HAC are preferred where high resistance is desired in resulting concrete. For temperatures of 2000 oC and above carbonacious refractories are a good option but they are expensive. The refractory castables can also be classified according to the CaO content in them. Regular castable rerfractories, also known as conventional castables usually have cement content more than 2.5%, low cement castables contain 1-2.5% CaO in them where as ultra low cement castables have 0.2- 1%. There are also no cement castables available which contain less than 0.2% CaO. The ratio of cement effects the strength and durability of the castable. The less the CaO ratio, durable is the product. Moreover, the chemical additives now used in refractory castables allow less water utilization for mixing. A device named permiameter is usually used to check the type of a castable. If the type is known it can surely prove its best in its respective fields.
Author Resource:
Further information about Castable Refractories can be found on the Castable Refractories manufacturer’s website.
![[Valid RSS feed]](http://www.look4articles.com/images/icon_Rss.png "XML Feed For RSS"){kind=icon}
Category Rss Feed
Print This Article
Add To Favorites
![[Valid RSS feed]](http://www.look4articles.com/images/rss.jpg "XML Feed For RSS")