What are the production methods of refractory materials?

According to the density and shape of the product, the production methods of refractory materials include sintering method, melting casting method and melt blowing method.

The sintering method is to pre-sinter some raw materials, crush and sieve them, and then mix them with raw materials according to a certain proportion, and then go through molding, drying and firing. The purpose of raw material pre-firing is to burn off the moisture, organic impurities and sulfates decomposed gas, so as to reduce the firing shrinkage of the product and ensure the accuracy of the product's external dimensions. The raw materials need to be sieved after crushing and grinding, because the blanks are graded by powders of different particle sizes, which can ensure the tightest packing to obtain dense blanks. 

In order to homogenize the components and particles of various raw materials and clinkers, kneading is carried out, and a binder is added at the same time to enhance the bonding strength of the billets. For example, the aluminum silicate blank is added with bound clay, the magnesium blank is added with sulfite pulp waste liquid, and the siliceous blank is added with lime milk. Depending on the moisture content of the blank, semi-dry molding (about 5% moisture), plastic molding (about 15% moisture) and grouting (about 40% moisture) can be used. It is then dried and fired.

The melting and casting method is to melt the raw materials at high temperature through processes such as batching mixing and fine grinding, direct casting, cooling and crystallization, and annealing to become products. Such as cast mullite bricks, corundum bricks and fused magnesia bricks. Their compact body, high mechanical strength, high-temperature structural strength, good slag resistance, and the scope of use is constantly expanding.

The melt blowing method is a method of melting the ingredients and blowing them with high-pressure air or superheated steam to disperse them into fibers or hollow spheres. Products are mainly used as lightweight refractory and heat insulation materials. In addition, it can also be made into powdered or granular unshaped refractory materials, which can be cemented with binders such as tar, asphalt, cement, phosphate, sulfate or chloride salt for temporary use, and used directly without molding and sintering.