Production process of refractory materials

According to the density and shape of the product, there are sintering method, melting casting method and melt injection method. The sintering method is to pre-burn the mature material of part of the raw materials, crush and screen, and then mix with the raw meal according to a certain ratio, and then form, dry and fire. The purpose of pre-firing raw materials is to burn out the water, organic impurities, and sulfate decomposition gases in them, so as to reduce the firing shrinkage of the products and ensure the accuracy of the dimensions of the products. The raw material also needs to be screened after crushing and grinding, because the blanks are graded from powders of different particle sizes, which guarantees the tightest packing and a dense body.

In order to homogenize the composition and particles of various raw meals and clinkers, a mixture is carried out and a binder is added at the same time to enhance the binding strength of the billet. For example, aluminum silicate blank is added to bonded clay, magnesium blank is added sulfurous acid pulp waste liquid, siliceous blank is added lime milk, etc. Depending on the moisture content of the blank, semi-dry molding (about 5% moisture), plastic molding (about 15% moisture) and grouting molding (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 the processes of batching and fine grinding, direct casting, cooling crystallization and annealing into products. Such as cast mullite bricks, corundum bricks and magnesia bricks. Their green body is dense, high mechanical strength, high temperature structural strength, good slag resistance, and the scope of use is constantly expanding. Melt injection is a method in which ingredients are melted and then sprayed with high-pressure air or superheated steam to disperse them into fibers or hollow balls. The products are mainly used as lightweight refractory and thermal insulation materials. In addition, it can also be made into powdered or granular amorphous refractories, cemented with tar, asphalt, cement, phosphate, sulfate or chloride and other binders when temporarily used, and can be used directly without molding and sintering.