The difference between the spinel brick and silicon mullite brick

This is the two kinds of products: silicon refractory mullite brick, mullite bricks should be. The main component is aluminum and silicon, crystalline mullite to A3S2 (3AL2O3.2SIO2). The main ingredient is magnesium spinel or spinel, namely MGO and Al2O3.

Mullite brick belongs to the silicon aluminum brick, the main characteristic is thermal expansion coefficient is low, good resistance to thermal shock, resistance to wear and chemical corrosion resistance.

Belong to the mg Al spinel brick brick, is the main characteristics of anti erosion ability,refractory material, good abrasion resistance, good heat shock stability. Their bulk density higher than mullite stoned. However, there are problems of spinel water, may react with steam powder. In this sense, the mullite is more stable.

What is said above the silicon mullite brick has many advantages, but we choose to forget a little, it is the main cause of low thermal conductivity! Refractory materials but resistance to chemical attack ability is not very good, also thermal shock is not very good, for the following reasons, pressure and thermal shock is inverse proportion relationship.

The main characteristics of spinel brick is resistance to mechanical stress better, refractory material is suitable for use in near tyre. For the water problems in the above posts have said, please note that the coefficient of thermal conductivity!

The causes and prevention methods of refractory brick cold burst

Refractory brick is to cold and hot, will burst, burst, the reason is very simple, when the cold and hot temperature, which burst due to thermal expansion and contraction, prone to refractory brick burst including following several types of refractory brick.

1, refractory brick minerals quartz, tridymite, cristobalite composition, due to the temperature change and also accompanied by quartz crystal type conversion, volume change, so the refractory brick thermal shock easily burst.

2, refractory brick by brick and magnesia chrome brick, due to thermal expansion coefficient, when the thermal shock, prone to burst.

Methods of prevention of refractory brick burst:

1, using the insulating fire brick, the insulating refractory brick has the function of heat insulation refractory brick inside, low and stable, is not easy to burst.

2 avoid cold and hot, slow heating and cooling is effective in the prevention of refractory brick burst.

3, the selection of heat coefficient is relatively high, refractory brick toughness is good, can reduce the probability of burst.

Application of silica brick in hot air furnace

In hot air furnace temperature is the highest part of the vault, a chunky “bottle” shape, bottleneck vertically according to the circular arc gradually shrink into a flue gas passage diameter with 1750mm “”. In the elevation of + 18.190 m furnace shell diameter expanded with 8010mm, the biggest part of crown, the crown began to merge with large wall masonry.

Precombustion chamber for hot blast stove top position, the total height of about 5m. The roof is covered by a semi spherical, ceramic fiber module under the “burner” system is a cylindrical structure, furnace shell diameter Φ 5094mm, which provided with annular gas, air collector refractory brick, gas, air “burner is provided with a total of 52 small diameter ceramic layer on the 2m high inner wall of the collector “

Precombustion chamber big wall thickness of 1317mm, the combustion space of 2460mm diameter. “Burner” system of flue gas outlet and the vault “bottleneck” cohesion. Gas, air through the external gas, air pipe to, by the gas, air collector 52 rotary jet “burner” implementation of gas combustion.

The low price of clay and silica refractory bricks, accounting for about 96% of all refractory material weight. Only in critical areas such as refractory brick precombustion chamber, a hot air outlet, use a small amount of a higher grade, such as Mo to brick, low creep high alumina brick, but only about 6% of the number of great wall.

Comprehensive understanding of various acid-base refractories

There is a kind of important properties — acid-base properties of many physical and chemical properties of refractory materials we must fully understand.

Acid refractory material determines its using temperature environment, anti slag corrosion ability, refractoriness under load, changes in the volume after repeated burning and thermal shock resistance. A comprehensive understanding of the acidity of the refractory material can achieve the best material, be just perfect use.

How acidity refractory material? Acid refractory usually refractory SiO2 content greater than 93%. Basic refractory materials generally refers to the refractory material to Magnesium Oxide or Magnesium Oxide and calcium oxide as the main component. The main characteristics of acid refractories is erosion resistant acid slag at high temperature, but easy to react with alkaline slag. Acid refractory materials are commonly used silica refractory bricks and clay bricks. Silicon refractory brick is siliceous materials silica containing more than 93%, raw materials used in silica, silica refractory bricks, the acid resistance of slag erosion ability, high refractoriness under load, the volume does not shrink after repeated burning, or even a slight expansion; but vulnerable to the erosion of basic slag, thermal shock resistance difference. Silicon refractory brick is mainly used for thermal equipment of coke oven, glass kiln, acid furnace etc.. Clay refractory bricks with refractory clay as the main raw material, containing 30% ~ 46% of alumina, is a weak acid refractories, good thermal shock resistance, resistance to acid slag, wide application. Basic refractory refractory degree is higher, the ability to resist the strong alkaline residue. For example, magnesia brick, magnesia chrome brick, magnesite chrome brick, magnesite, dolomite brick, forsterite bricks etc.. Mainly used for basic steelmaking furnace, smelting furnace for non-ferrous metal and cement kiln etc.