Refractory It is an adjective that comes from the Latin word refractarius. The dictionary of the Royal Spanish Academy (RAE ) mentions different meanings of the term: the first refers to the individual who rejects the fulfillment of an obligation or duty .
Someone refractory, therefore, shows rebellion to abide by a mandate or to accept a thought different from yours. For example: "The player was refractory to the indications of his coach and was replaced before the end of the first half", "The mayor is refractory to journalistic consultations: that's why he prefers not to talk to the press", “The young man, refractory, insulted the police before being arrested”.
The refractory materials , on the other hand, are those that have a good resistance to the fire , that is, to endure its action without suffering alterations. It is about materials that tolerate high temperatures without breaking down nor modify its properties.
Although there is no definition, specify when a material can be qualified as refractory, it is generally considered to be if it is able to tolerate temperatures higher than 1100 ° C Without suffering a deformation.
The lime , he silica , the alumina and the magnesium oxide They are some of the refractory materials. This means that these materials have a reduced thermal conductivity, resist thermal shocks and do not expand before temperatures high.
Due to their characteristics, refractory materials are used to coat incinerators and ovens and for the manufacture of pots .
It is known as brick Refractory to a class of ceramic material that has a number of very particular characteristics that make it especially versatile for use in the field of industry. It has smooth faces, a feature that makes it less adherent to the mortar, and this makes it more resistant to abrasion and high temperatures. Mortar, meanwhile, is a compound that is used to glue stones, concrete blocks, bricks and other building elements.
Refractory brick is quite expensive, but compensates the economic investment with its thermal properties . Currently, it is used for coating of boilers, rotary furnaces, grills and acceleration pots, for example, and to adhere them to each other it is used refractory land ; It should be mentioned that the cement can make the joint firmer, and therefore it can be added to the mixture, which looks similar to mud.
Manipulating a refractory brick is more complicated than a common one, since it can generate an explosion if it is not combined with the right materials. As with refractory earth, this type of brick is a very good container of hot , that is, it has the capacity to conserve the temperature to which it is exposed throughout the different processes it goes through.
The percentage of alumina concentration that is used in the manufacture of a refractory brick (which can be as low as a 36% and as tall as a 99% ) directly influences its resistance to high temperatures. Another material that can be used is silica, and this decision together with the percentage of alumina derives in the quality of the final product. If it is not desired to subject it to very varied temperatures, it does not need to contain much alumina.
For him covering of furnaces that are used to melt steel, a refractory brick of silicon dioxide , which usually begins to liquefy when the temperature exceeds 1650 ° C. Its manufacture requires exposing the components to low pressures and burning them at very high temperatures.