2023

What are the types of refractory materials?

Source: Network

Refractory materials are widely used in metallurgy, chemical industry, petroleum, machinery manufacturing, silicate, power and other industrial areas. It is a class of inorganic non-metallic materials with a refractoriness of not less than 1580 ℃. So what are the types of refractory materials?

Refractory materials according to the proportion of the formula is not the same as more than 10000 kinds, but generally according to the degree of fire resistance is divided into general refractory materials (1580~1770 ℃), advanced refractory materials (1770~2000 ℃) and special refractory materials (above 2000 ℃).

According to the chemical characteristics of acid refractories, neutral refractories and alkaline refractories, according to the density can also be divided into light refractories and heavy refractories. According to the shape can be divided into shaped refractory and amorphous refractory, shaped products for all kinds of refractory brick products, amorphous products for all kinds of refractory castable.

Taking light refractory materials and heavy refractory materials as an example, light refractory materials are refractory materials with high porosity, low volume density and low thermal conductivity. Used as insulation on industrial kilns and other thermal equipment. Compared with the general refractory brick, the slag corrosion resistance, mechanical strength, wear resistance is poor, and the volume is shortened at high temperature. Industrial kiln masonry heat storage loss and furnace surface heat loss, generally about 24 to 45% of fuel consumption. Using light bricks with low thermal conductivity and small thermal capacity as furnace structure materials can save fuel consumption; because the kiln can be quickly heated and cooled, it can advance the production power of the equipment; it can also reduce the weight of the furnace body, simplify the kiln structure, advance product quality, reduce the ambient temperature, and improve working conditions. However, the light refractory brick porosity is larger, loose arrangement, can not be used for direct contact with slag and liquid metal parts; mechanical strength is low, can not be used for load-bearing structure; wear-resistant function is very poor, should not be used for contact with the burden, wear serious parts.

Heavy refractories are a class of inorganic non-metallic materials with a density of more than 2.0g/cm³ and a refractoriness of not less than 1580 ℃. Refractoriness refers to the temperature of the refractory cone sample in the absence of load, to resist the effect of high temperature without softening and melting. It can directly contact the flame and has the characteristics of high temperature resistance and wear resistance, which is one of the essential refractory materials for the kiln. In the use of the furnace should be light refractory materials and heavy refractory materials mixed use, can play a better effect.

Shaped refractory materials are divided into heavy refractory bricks and light thermal insulation bricks. Heavy refractory bricks are representative of high-alumina bricks, which are divided into three grades according to the content of aluminum oxide Al2O3: grade I-Al2O4 content> 75%; Grade II-Al2O4 content is 60 ~ 75%; Grade III-Al2O4 content is 48 ~ 60%. The alumina content of high alumina brick above 48% is attributed to neutral refractory material. It is formed by forming and calcining alumina or other materials with high alumina content. Commonly used in masonry steel-making furnace, glass melting furnace, cement rotary furnace and other cloth.

Light insulation products are more common than light mullite insulation bricks, high alumina refractory materials with mullite as the main crystal phase. Generally, the alumina content is between 65% and 75%. In addition to mullite, those with low alumina content are rich in a small amount of glass phase and cristobalite; those with high alumina content are also rich in a small amount of corundum. High refractoriness, up to 1790 ℃. It is mainly used for hot blast stove top, blast furnace body and bottom, glass melting furnace heat storage chamber, ceramic sintering kiln, dead angle furnace lining of petroleum cracking system, etc.

Unshaped refractory materials are various types of refractory castables, plastic materials, spray coatings, etc. The refractory function is comparable to that of high-strength corundum refractory castables. High-function refractory castables mainly include high alumina, mullite and corundum. These products have the characteristics of high strength, stable thermal shock function, excellent application function, etc. They are widely used in the lining of industrial kilns such as pellet rotary kilns and heating furnaces.

Key words:

What are the types of refractory materials?