Production process of refractory materials
According to the density and shape of the product, there are methods such as sintering, melting casting, and melt blowing. The sintering method is to preheat and mature some raw materials, crush and screen them, and then mix them with raw materials according to a certain ratio, followed by molding, drying and firing. The purpose of pre firing raw materials is to remove moisture, organic impurities, and gases from the decomposition of sulfates, in order to reduce the shrinkage of the product during firing and ensure the accuracy of the product's external dimensions. After crushing and grinding, the raw materials also need to be screened because the raw materials are graded with different particle sizes of powder, which can ensure the closest packing and obtain a dense body.
In order to homogenize the composition and particles of various raw materials and clinker, mixing should be carried out while adding binders to enhance the bonding strength of the billet. For example, adding bonded clay to aluminum silicate blanks, adding sulfite pulp waste liquid to magnesium blanks, and adding lime milk to siliceous blanks. According to the moisture content of the billet, semi dry molding (containing about 5% moisture), plastic molding (containing about 15% moisture), and grouting molding (containing about 40% moisture) can be used. Then dry and burn. The melting casting method is a process of mixing raw materials evenly and finely grinding them, melting them at high temperatures, directly casting them, cooling and crystallizing them, and annealing them into products. Such as melted and cast mullite bricks, corundum bricks, and magnesia bricks. Their bodies are dense, with high mechanical strength, high high-temperature structural strength, good slag resistance, and their range of use is constantly expanding. The melt blowing method is a method of dispersing ingredients into fibers or hollow spheres by blowing them with high-pressure air or superheated steam after melting. The product is mainly used as a lightweight refractory and thermal insulation material. In addition, it can also be made into powder or granular amorphous refractory materials, which can be bonded with binders such as tar, asphalt, cement, phosphate, sulfate or chloride salts before use, and can be used directly without forming or sintering.
