Refractories are generally divided into two types, namely unshaped refractories and shaped refractories. Unshaped refractories are also called castables, which are mixed powder particles composed of a variety of aggregates or aggregates and one or more binders. When used, they must be mixed with one or more liquids and mixed evenly. Strong liquidity. Shaped refractory materials generally refer to refractory bricks, the shape of which has standard rules, and it can also be temporarily processed when needed.
Refractory brick is referred to as fire brick. Refractory made of fire-resistant clay or other refractory materials. Pale yellow or brown. It is mainly used for building smelting furnaces and can withstand high temperatures of 1,580℃-1,770℃. Also called firebrick. A refractory material with a certain shape and size. According to the preparation process, it can be divided into fired bricks, non-fired bricks, fused bricks (fused cast bricks), refractory and heat insulation bricks; according to the shape and size, it can be divided into standard bricks, ordinary bricks, special bricks, etc. It can be used as high temperature building materials and structural materials for building kilns and various thermal equipment, and can withstand various physical and chemical changes and mechanical effects at high temperatures. For example, refractory clay bricks, high alumina bricks, silica bricks, magnesia bricks, etc.
Own attributes
1. Chemical composition: the main components determine the quality and characteristics of the refractory
2. Volume density: weight per unit volume, high density, indicating good compactness, the strength may be high, but the thermal conductivity may be large
3. Obvious porosity: No specific requirements are made, but as a manufacturer, the obvious porosity must be strictly controlled.
4. Load softening temperature: also called high temperature load starting deformation temperature, this parameter is very important, marking the resistance of the material to high temperature
5. Thermal shock resistance: the ability to resist sudden changes in temperature without being destroyed
6. Compressive strength: the maximum pressure ability to withstand (normal temperature)
7. Flexural strength: the ability to withstand shear pressure
8. Linear rate of change: also called reburning line change or residual line change, which refers to the change in volume expansion and contraction in the same temperature change every time. If each expansion and contraction is the same, we define such a linear change rate as 0
Physical and chemical properties
1. Wear resistance:
2. Thermal conductivity: Under the condition of unit temperature gradient, the heat flow rate per unit area of the material is related to the porosity
3. Impact resistance: no need to explain, it has good impact resistance and long service life
4. Slag resistance: the ability to resist the erosion of molten slag without being destroyed at high temperatures
According to the different components of refractory bricks, they can be divided into five categories, namely: silica-alumina refractory bricks, alkaline refractory bricks, carbon-containing refractory bricks, zirconium-containing refractory bricks, and heat-insulating refractory bricks. Any stove is not just built with one kind of refractory bricks, it needs a combination of different refractory bricks.
1. The silicon-aluminum refractory bricks are reported to be based on the phase diagram of the AL2O3-SiO2 binary system.
2. Alkaline series refractory bricks. Alkaline refractory bricks refer to refractory products with alkaline oxides such as Mg0 and CaO as the main components. The main varieties are as follows
3. Carbon-containing refractory bricks. Carbon-containing refractory bricks refer to the refractory brick products made of carbon or carbon compounds. The refractory brick products containing different forms of carbon as the main component are mainly divided into the following types
4. Zirconium-containing refractory bricks. It belongs to an acidic material and is a product made from natural zircon sand (ZrSiO2). Zirconium refractory bricks are different from silicon-aluminum refractory bricks and carbon-containing refractory bricks. It has good slag resistance, low thermal expansion rate, thermal conductivity decreases with increasing temperature, high load softening temperature, and high wear resistance. With good thermal shock resistance, it has become an important material in various industrial fields. With the development of continuous casting and vacuum degassing technology in the metallurgical industry, zircon refractory bricks are used more and more widely, mainly in the following categories
5. Insulation refractory bricks. It refers to a refractory with high porosity, low bulk density and low thermal conductivity. Insulating refractories, also known as lightweight refractories