Performance And Physicochemical Indicators Of Magnesia Alumina Spinel Bricks

Performance and physicochemical indicators of magnesia alumina spinel bricks
Magnesium aluminum spinel bricks have the characteristics of good thermal shock stability, high mechanical strength at high temperatures, high load softening temperature, good slag resistance, and strong resistance to vacuum volatility.
Taking RMA series magnesia alumina spinel bricks as an example, their physical and chemical indicators include MgO content of 82% to 88%, Al2O3 content of 6% to 9%, SiO2 content of 0.5% to 1.0%, bulk density of 2.80 to 2.90 g/cm ³, apparent porosity of 18% to 20%, room temperature compressive strength of 45 to 60 MPa, load softening temperature of 1650 to 1700 ℃, thermal shock stability (1100 ℃, water-cooled) not less than 10 times, and thermal conductivity (1000 ℃) of 2.7 to 2.9 W/m · K.
In terms of bulk density and porosity, products with low porosity (less than 9%) can achieve a bulk density of 3.22-3.23 g/cm ³; The bulk density of pores with a porosity of 12-17% is 2.9-3.1 g/cm ³. Due to the high direct bonding rate between high melting point grains, the strength is high at normal and high temperatures, and the softening temperature under load can reach 1700-1750 ℃, with strong creep resistance.
In terms of slag resistance, it has strong resistance to the infiltration of silicate and iron containing slag, is not easy to form a thick metamorphic layer, and has excellent resistance to direct erosion by slag.
In terms of resistance to vacuum volatility, it has low volatility in vacuum and good resistance to vacuum volatility.
In terms of thermal shock stability, the coefficient of thermal expansion is relatively low (8.2 × 10 ⁻⁶/℃), and the thermal shock resistance is good. The water cooling cycle at 1300 ℃ can reach 6-13 times; When there is too much MgO or A12O3 in the brick, its thermal shock resistance may be reduced.
Main product types
Magnesium aluminum spinel bricks mainly include unburned and fired block bricks, and can also be synthesized into amorphous refractory materials using spinel.
Burnt magnesia alumina spinel bricks
Magnesia alumina spinel bricks are fired at high temperatures and have characteristics such as high density, low porosity, and high strength. Its production process is similar to ordinary magnesia bricks, but the ingredients are composed of sintered or fused spinel. The billet needs to be formed under high pressure (usually 120-200MPa) and fired at high temperature (such as 1750 ℃). After firing, the porosity can be less than 9%, and the bulk density can reach 3.22-3.23 g/cm ³. It has high strength at room temperature and high temperature, and the softening temperature under load is 1700-1750 ℃. It has excellent slag resistance and thermal shock stability.
Do not burn magnesia alumina spinel bricks
Non fired magnesia alumina spinel bricks are one of the main types of products.
Amorphous refractory material
Amorphous refractory materials are made from synthetic spinel as raw materials, used to form integral structures and spray repair linings.
Classified by spinel synthesis method
According to the synthesis method of spinel raw materials, they can be divided into sintered spinel bricks and fused spinel bricks. The particle materials in the ingredients are composed of sintered synthesized spinel or fused synthesized spinel, or a mixture of both.