I.The production process of refractory materials:
Depending on the degree of compactness and shape of the product, there are sintering methods, melt casting methods, and melt blowing methods. The sintering method is to pre-burn a part of the raw materials, crush and sift, and then mix with the raw materials according to a certain ratio, after molding, drying and firing. The purpose of raw material calcination is to burn off the water, organic impurities, and sulfate decomposition gas to reduce the firing shrinkage of the product and ensure the accuracy of the product dimensions. The raw materials need to be sieved after being crushed and ground, because the blanks are graded by powders of different particle sizes to ensure the closest packing to obtain a dense body.
In order to homogenize the ingredients and granules of various raw materials and clinker, kneading is carried out while adding a binder to enhance the bond strength of the billet. For example, an aluminum silicate billet is added to the combined clay, a magnesia billet is added to the sulfite pulp waste liquid, and the siliceous billet is added to the lime milk. Depending on the water content of the blank, it can be formed by semi-dry molding (about 5% moisture), plastic molding (about 15% moisture) and grouting (about 40% moisture). It is then dried and fired. The smelting method is a process in which raw materials are mixed and finely ground, and melted at a high temperature, directly cast, cooled and crystallized, and annealed to form a product. Such as casting mullite bricks, corundum bricks and magnesium bricks. Their bodies are dense, with high mechanical strength, high structural strength, good slag resistance, and the use range is constantly expanding. The melt blowing method is a method in which the ingredients are melted and then sprayed with high-pressure air or superheated steam to disperse them into fibers or hollow spheres. The products are mainly used as lightweight refractory and heat insulating materials. In addition, it can be made into a powdery or granular unshaped refractory material. It can be cemented with a binder such as tar, asphalt, cement, phosphate, sulfate or chloride when it is used. It can be used directly without molding and sintering.
Special materials commonly used in refractory abrasives are AZS bricks, corundum bricks, direct bonded magnesia chrome bricks, silicon carbide bricks, silicon nitride bonded silicon carbide bricks, nitrides, silicides, sulfides, borides, carbides, etc. Oxide refractory; refractory materials such as calcium oxide, chromium oxide, aluminum oxide, magnesium oxide, cerium oxide. Frequently used insulating refractories are diatomite products, asbestos products, insulation panels, and the like. Commonly used amorphous refractories are replenishing materials, ramming materials, castables, plastics, refractory clay, spray materials, projection materials, paints, lightweight refractory castables, and mortar.