There are many kinds of refractories. According to its appearance classification, refractories can be divided into refractory bricks (products with certain shape) and unshaped refractories (referred to as bulk materials). Refractory bricks are divided into four categories: sintered bricks, unsintered bricks, electric melting bricks (fused cast bricks) and refractory heat insulation bricks.
The refractories used in glass furnace are mainly cast refractories, sintering refractories and amorphous refractories. The fused refractories are divided into two series: fused zirconia corundum and fused alumina. They are mainly used in float glass furnace, electronic glass furnace, daily glass furnace, glass fiber, special glass, some ordinary flat glass furnace and lattice glass furnace. Refractories are the most important building materials in the glass furnace, which directly contact with the liquid glass. Their quality directly affects the quality of glass and the technological progress of glass furnace. In the structural adjustment of China's glass industry, high-quality casting refractories play an important role.
1. Sintered refractory
After the raw materials are selected, purified, homogenized, broken, crushed and graded, appropriate binders are added, and the mixture is made according to the proposed proportion. Through the forming machine, the blank is processed into a certain shape of the blank, and then dried and heat treated to make it a fixed shape product with expected microstructure and performance. It is called sintered refractory.
This type of products are: aluminum silicate refractory products, silica refractory products, magnesia refractory products and light refractory products.
2. Fused refractory
The fused refractory refers to the product which is cast into a certain shape after the mixture is melted at high temperature. At present, electrofusion is the main method to produce fused cast refractories. The electric melting refractory material is to melt the precisely prepared mixture in the electric arc furnace, then cast it in the sand mold, and then machine the ingot after heat treatment. In the melting process, a complete coarse crystal and a compact structure can be obtained. Compared with sintered refractories, it has the characteristics of compact structure, low porosity, large bulk density, high mechanical strength and high temperature structural strength, and strong resistance to erosion of glass liquid.
The important indexes to evaluate the performance of the refractories are: chemical and crystal phase composition, bulk density, glass phase exudation temperature, glass phase exudation amount and foaming rate. The meaning of foaming is that when O2 diffuses into the brick and reacts with the carbon or carbide, sulfide and nitride contained in the brick, CO2, SO2, N2 and other gases are released, which extrude the molten phase out of the brick and form visible bubbles on the surface. At present, the main products are: fused mullite brick, fused zirconia corundum brick, fused chrome zirconia corundum brick, fused quartz brick, fus3. Amorphous refractory
3,Amorphous refractories, also known as bulk refractories, are refractories which are composed of certain graded refractory aggregate and powder materials mixed with binders and admixtures, and are directly used without forming and firing processes. Compared with the refractory brick, the amorphous refractory material has the advantages of simple technology (because of eliminating the firing process), energy saving, low cost, and convenient for mechanized construction.
There are many kinds of amorphous refractories. According to the material classification of the used refractories, such as siliceous, clayey, high alumina, magnesia, dolomite, chrome, zirconium, etc.; according to the types of binders used, such as tar pitch, aluminate cement, silicate, sulfate, chloride, etc. Generally, according to its technological characteristics, it can be divided into refractory mud, ramming refractory material (referred to as ramming material), plastic refractory material (referred to as plastic), pouring or pouring refractory material (referred to as pouring material or pouring material), refractory concrete and spraying refractory material (referred to as spraying material), etc.ed corundum brick, etc.
