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Magnesia-alumina spinel brick (periclase-spinel brick)

Magnesium aluminum spinel brick, is my company using high purity magnesium oxide and fused magnesium aluminum spinel as raw materials, manufactured by a special process. Due to the use of "in situ spinel" technology and high purity raw materials, the products have strong wear resistance at high temperature, especially suitable for thermal stress, chemical stress, output load of the cement rotary kiln transition zone.

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Refractory materials for cement industry

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Product Introduction

　　1. Performance characteristics:

1) Thermal shock resistance. The main mineral composition of magnesia-alumina spinel brick is periclase (MgO) and spinel (MgAl2O4), both of which are equiaxed crystal system, and the thermal expansion is isotropic. Because the thermal expansion coefficient of spinel is 7.6 × 10-6 and that of periclase is 13.5 × 10-6, the difference is large, and the high-temperature phase transformation of special additives causes a large number of spherical micro-pores and micro-cracks to form inside the product during the firing, the existence of microcracks is beneficial to improve the structural toughness of the product, buffer thermal stress, and stop the formation of crack propagation. Therefore, magnesium aluminate spinel bricks have high thermal shock resistance and structural spalling resistance.

2) High strength. The increase of spinel content in the matrix of magnesium aluminate spinel brick increases the ratio of spinel to periclase. Because the dihedral angle between different grains is greater than that of the same grain, the number of second solid phase bonding is increased in the matrix, thus improving the organizational structure of the matrix part, so the strength is high and the wear resistance is high.

3) Anti-erosion. The melting point of MgO (melting point 2805 ℃) and MA (melting point 2105 ℃) in the product is 1995 ℃, and the two have certain mutual solubility. During use, the reaction rate of spinel minerals in the product with R2O3(Na2O, K2O) and SO3 in cement clinker is much lower than Cr2O3; And the melting points of potassium aluminate and sodium aluminate produced by the reaction are 500-600 ℃ higher than potassium chromate and sodium chromate. At the same time, trace impurities exist in isolation, closing the pores and blocking the slag channel. Therefore, the corrosion resistance of the product is another grade.

　　2. Physical and chemical indexes:

Project	HWMAF-A	HWMAF-B	MAF-C
Project	Standard value	Standard value	Standard value
MgO(%)≥	87	85	83
Al₂O₃ (%)	9-11	10-12	10-12
Fe₂O₃(%)≤	0.8	1.0	1.0
SiO₂(%)≤	0.6	1.0	1.2
Percent porosity (%)≤	17	18	18
Bulk density g/cm³≥	2.96	2.93	2.9
Normal temperature compressive strength (MPa)≥	70	65	60
0.2 MPa load softening temperature (T0.6 ℃)>	1700	1700	1700
Thermal shock stability (1100 ℃ water cooling) times ≥	12	10	10