Refractory properties, scope of application and service life

Posted by ariel li on September 29th, 2017

(1580-1770 ℃), high-grade refractory materials (1770-2000 ℃) and special refractory materials (above 2000 ℃); according to the chemical characteristics of acid refractory materials, according to the chemical characteristics of refractory materials, Neutral refractory materials and alkaline refractories. In addition, there are refractory materials for special occasions.
Now for the definition of refractories, has not only depends on the refractoriness is above 1580 ℃. Refractory materials are currently used in metallurgy, petrochemical, cement, ceramics and other production equipment lining the inorganic non-metallic materials.

First, the acid refractory material

Acid refractory material to silicon oxide (SiO2) as the main component, commonly used silica brick and clay brick. Silica brick is containing more than 93% of silicon silicate products, the use of raw materials are silica, waste silicon brick.
Silica brick anti-acid slag erosion ability, but vulnerable to alkaline slag erosion, and its load softening temperature is very high, close to its refractoriness, repeated exercise after the volume does not shrink, or even slightly inflated, poor thermal shock stability. Silica brick is mainly used for coke oven, glass melting furnace acidic steel-making furnace and other thermal equipment, silica brick in accordance with the SiO2 content and physical and chemical indicators can be divided into several levels, mainly divided into glass kiln with silicon brick and coke oven Two categories.
Clay brick with refractory clay or gemstone clinker as the main raw material, containing 30% -46% of alumina, refractoriness 1580-1770 ℃, is a weak acid refractory, thermal shock resistance, acid corrosion resistance , Widely used in clay bricks to refractory clay as the main raw material produced by the ordinary clay brick, coke gem clinker as the main raw material, the porosity of 17% below the clay brick called low porosity clay brick.
→ two kinds of clay brick and according to which the physical and chemical indicators are divided into several levels, ordinary clay brick and low porosity clay brick between the price difference.

Second, neutral refractories

Neutral refractories are mainly composed of alumina, chromium oxide, silicon carbide or carbon. Neutral refractory main products are: corundum brick, high alumina brick, silicon brick, mullite brick, aluminum chrome brick, aluminum carbon brick, graphite or carbon brick. High alumina products in the main crystal phase is mullite and corundum, corundum content with the increase in alumina content increased, more than 95% alumina corundum products is a wide range of high-quality refractory materials. Chromium chrome as the main component of the chromium brick on the steel slag of good corrosion resistance, but the thermal shock resistance is poor, the load softening degree of alkali erosion resistance is poor, it can not be applied to the use of complex conditions, the key parts, Using bauxite and silicon carbide two materials as the main raw material, mainly used for cement rotary kiln transition zone.

Third, carbon refractories

Carbon refractories are carbon brick, graphite products and silicon carbide products. Carbon products are another kind of neutral refractory material, according to the composition of carbonaceous materials and products of mineral composition, divided into carbon brick, graphite products and silicon carbide products three categories.
Carbon brick is a high grade petroleum coke as raw material, plus tar, asphalt as a binder, at 1300 ℃ under the conditions of air burning. Graphite products (except for natural graphite) with carbonaceous materials in the electric furnace in the nitrogen atmosphere made of silicon nitride - silicon carbide products. Carbon products, thermal expansion coefficient is very low, high thermal conductivity, thermal shock resistance, high temperature strength. Long-term use at high temperatures do not soften, from any acid-base erosion, good salt resistance, but also from the metal and slag wetting, light, high-quality refractory refractory materials. Disadvantages are easy to oxidize at high temperatures, and should not be used in an oxidizing atmosphere. Carbon products are widely used in high temperature furnace lining (bottom, hearth, furnace body, etc.), smelting non-ferrous metal furnace lining.
Graphite products can be used as reaction tank and petrochemical kettle lining. Silicon carbide and graphite products can also be made into smelting copper alloy and light alloy crucible. Carbon brick and graphite products, the main component of carbon (C), its thermal expansion coefficient is very low, high thermal conductivity, good thermal shock resistance, high temperature strength, acid and salt erosion, especially weak acid Of the resistance, not from the metal and slag melting wet, light, generally used in iron and steel smelting industry, but also for the oil, chemical industry, autoclave lining. Silicon carbide is an excellent refractory material, good corrosion resistance, but at high temperature (higher than 1400 degrees) easy to oxidation, is not suitable for use in the oxidizing atmosphere.

Fourth, alkaline refractories

The main products are magnesia brick, magnesia chrome brick, magnesium zirconium brick, magnesium aluminum brick, magnesium aluminum spinel brick, magnesia bricks, dolomite brick and the latest development of alkaline refractory materials to magnesium oxide, calcium oxide as the main component Of the mafic spinel bricks. Magnesite (Mgo) more than 80% of the refractory brick is called magnesium bricks, according to the indicators can be divided into many grades, magnesia on the basic slag and iron slag has a good resistance, refractoriness than clay brick and silica brick The Mainly used for the furnace, oxygen converter, electric furnace, non-ferrous metal smelting equipment and glass industry and some high-temperature equipment. Magnesium chrome brick is more resistant to alkaline slag, and the thermal shock resistance is much higher than that of magnesia brick, so the application is more extensive, magnesia chrome brick in the iron and steel smelting and nonferrous metal smelting industry has almost replaced the magnesium brick The

Magnesium spinel brick is a new product, mainly used for cement rotary kiln firing zone and transition zone, will be the cement industry to replace the main products of magnesia chrome brick.


Related Articles:

http://www.ruizhirefractory.com/en/new/refractory-definition.html

Email: sales@ruizhirefractory.com