China Supplier Steel Furnace MgO Magnesia Refractory Brick/Magnesia Brick With Good Price

Magnesia brick is an alkaline refractory material with a magnesia content of more than 90% and a periclsite as the main phase. Generally, it can be divided into two categories:sintered magnesia brick (also known as burnt magnesia brick) and chemically combined magnesia brick (also known as non-burned magnesia brick). Magnesia bricks with high purity and high firing temperature are called direct-bonded magnesia bricks because of the direct contact of the magnesite grains. The bricks made of fused magnesia are called electrofusion and recombined magnesia bricks.
Magnesia bricks have high refractoriness, good resistance to alkaline slag, high starting temperature of load softening, but poor thermal shock resistance. The sintered magnesia brick is made of brick and magnesia bricks. After being pulverized, compounded, kneaded and formed, it is fired at a high temperature of 1550 to 1600 ° C. The high-purity product has a firing temperature of 1750 ° C or higher. The non-casting magnesia brick is made by adding a suitable chemical binder to the magnesia, mixing, forming and drying.
Magnesia brick Mainly used in steelmaking alkaline open hearth furnace, electric furnace bottom and furnace wall, permanent lining of oxygen converter, non-ferrous metal smelting furnace, high temperature tunnel kiln, calcined magnesia brick and cement rotary kiln lining, heating furnace bottom and furnace wall, Glass kiln regenerator lattice bricks, etc.
Magnesia brick The sintered magnesia brick is made of brick and magnesia bricks. After being pulverized, compounded, kneaded and formed, it is fired at a high temperature of 1550 to 1600 ° C. The high-purity product has a firing temperature of 1750 ° C or higher. The non-casting magnesia brick is made by adding a suitable chemical binder to the magnesia, mixing, forming and drying.

Manufacturing process of five kinds of magnesia bricks such as magnesium aluminum brick

Manufacture magnesia silica brick
In order to make full use of the high-silica magnesia having a SiO2 content of 5 to 11%, a magnesia-silica brick can be produced by a production process for producing a magnesia brick. Unlike the calcined magnesia brick, since the forsterite (M2S) is not easily sintered, the calcination temperature of the magnesia silica brick should be appropriately increased.
The firing temperature of the magnesia silica brick is 1550 to 1570 °C.

Manufacturing magnesia-calcium brick
In order to make full use of high-calcium magnesite, magnesia-calcium bricks can be produced.
The production process of magnesia-calcium bricks is divided into two processes of clinker preparation and brick making. Preparation of magnesia-calcium sand clinker, the ratio of calcium to silicon (C/S) should be controlled between 2.2 and 3.0, Al2O3 should be less than 2%, and 0.3% apatite should be added as stabilizer to add 0.5~0.7% iron concentrate. Mineral powder as a mineralizer.
The high-calcium magnesite, apatite and iron concentrate are co-milled in a cylindrical mill. Particle size requirements: <0.088mm fine powder is greater than 90%. The powder is fired in a rotary kiln after being formed into a ball.
The high calcium magnesium brick is prepared by using high calcium magnesium sand as a raw material and bricks produced by firing the magnesium brick production process at 1600~1680 °C.

Manufacturing magnesium aluminum brick
Magnesium-aluminum bricks can be obtained by adding 5~10% Al2O3 to the sintered magnesia. A12O3 is added to the fine powder in the form of industrial alumina or high alumina bauxite.
If Al2O3 is introduced with high alumina ground, it is inevitable that impurities such as SiO2 are also introduced, thereby reducing the refractoriness and high temperature strength of the product. Therefore, the amount of bauxite should not be too large.
The process parameters for the manufacture of magnesium-aluminum bricks are similar to those of magnesia bricks. Only the firing temperature is generally 30 to 50 ° C higher than the firing temperature of the magnesia brick, reaching 1750 to 1800 ° C

Making periclase-magnesium aluminum spinel brick
The first-class brick magnesia and sintered magnesium-aluminum spinel sand with a C/S ratio of 0.4 are used as raw materials, and the critical particle size of the particles is 3 mm. The size of the magnesia is 3~1mm large particles, <1mm medium particles and <0.088mm fine powder are used as the tertiary ingredients. The sulfite pulp waste liquid is used as a binder, and is mixed with a wet mill to form a 300t friction brick machine. After the body is dried, it is fired at 1560 to 1590 °C. A weak oxidizing atmosphere should be controlled during the firing process.
The high temperature mechanical properties and thermal shock stability of periclase-spinel bricks are superior to ordinary magnesia-aluminum bricks. Its normal temperature compressive strength is 70~100MPa, thermal shock stability (1000 °C, water cooling) 14~19 times. The periclase-spinel brick can be applied to the high temperature zone of the active lime rotary kiln and the cement rotary kiln.
Manufacture of fired oil-impregnated magnesium dolomite brick
High-purity magnesia and magnesium dolomite sand with a MgO content of 95% or more are used as raw materials, which are crushed, crushed and used. The large particle and the medium particle material are heated to a certain temperature, and a certain amount of medium temperature asphalt (paraffin solution or random polypropylene) is added, and after stirring, fine powder is added, and after mixing, it is formed by a friction brick machine, and is formed at 1600~1650 °C. Burnt.
After the calcined bricks are preheated and vacuum-treated, they are impregnated in the asphalt at a high temperature, and then cooled to normal temperature.

Manufacture of synthetic magnesium chrome spinel bricks
Magnesium-chromium spinel bricks can be produced by using pre-reacted magnesia chrome sand and magnesia as raw materials and brine as a binder. The ingredients are as follows: pre-reacted magnesia chrome (particle size <0.066mm) 30%, magnesia (particle size <3mm) 55%, magnesia (particle size <0.088mm) 15%, plus brine 3%. The material is mixed by a wet mill, and the feeding sequence is: granular material→binding agent→fine powder, and the mixing time is not less than 10 minutes. Formed by a 260t friction brick press, the density of the green body is controlled at 3.05g/cm3, and the apparent porosity is not more than 16%. The green body was dried and fired at 1600 °C.
The physical properties of the product are as follows: apparent porosity of 15%, bulk density of 3.09g/cm3, normal temperature compressive strength of 86MPa, load softening temperature of more than 1700 ° C, thermal shock stability (1100 ° C, water cooling) 7 times.