What are the components of refractory clay?
The component of refractory mortar comprises refractory powder, binders and admixtures. Almost all the refractory materials can be used as the powder to formulate refractory mortar. Ordinary refractory mortar is made from refractory chamotte powder, an appropriate amount of plastic clay as binding agent and plasticizer. It has low strength under normal temperature, but the ceramic formed under high temperature has a high strength. Refractory mortar which is formed with bonding material of hydraulicity, gas or thermal hardness is called chemical binding chamotte refractory mortar. It is hradened through chemical reaction before below the temperature of ceramic bonding formation.
It is different from non-cement castable refractories, which does not rely on the addition of cement for combination, instead it uses chemical binder. It is refractory castable (also known as chemical bonding castable). Non-cement refractory castable takes oxide or synthetic compound ultra-fine powder or oxide sol-gel which is similar to the chemical composition of material in tungsten castable. Since the use of superfine powder or sol as binder, it has low impurity content, and therefore the refractoriness and slag erosion resistance of the castable will not be reduced. Besides, the self combination in use can help to improve high-temperature structural strength. Non-cement castable refractory is made up of refractory aggregate and powder, superfine powder of oxide or sol, trace amount of dispergator (or anti-coagulant) and proper slow acting hardener. Non-cement castable is mainly coagulated and combinated by ultrafine powder of oxide or sol, therefore, it has certain requirements for ultrafine and sol. Ultrafine powder used refers to less than 1 / zm particles. Ultrafine powder used in non-cement castables are SiO2, Al2O3, Cr2zrOz, etc. SiO micro powder is often adopted, which is the dust recycled during the smelting of metallic silicon, ferro-silicon alloy, the generation process is as follows: This recycled SiO2 powder has an average particle diameter of 0.5 pM, and it is spherical with large surface area. It is amorphous substance with high activity, so it has good bonding strength. The sol used are mainly alumina oxide and silica sol. Silica sol is made by ion exchange of sodium silicate after Na ions are removed. It can also be made after hydrolysis of ethyl silicate. There are several ways of preparing alumina sol, the easiest method is to prepare by the reaction of metallic aluminum or alchlor with hydrochloric acid.
The major raw material are bauxite, magnesite, silica, etc. It is easy to combine, high temperature resistant, corrosion resistant and has other advantages. It can be applied for refractory bricks in a variety of masonry.
