Magnesium alumina spinel brick is a kind of advanced alkaline refractory material with perriclase as main phase magnesia alumina spinel clinker as basic material. Superior strength at ambient and elevated temperatures, better corrosion, erosion and abrasion resistance and thermal shock resistance makes it an excellent refractory material.
Magnesium alumina spinel is a member of a group of oxides that have the same crystal structure, which is named the spinel structure. Magnesium aluminate spinel is synthesized and then added to magnesia refractory brick compositions in the range of 0–30 weight percentages. The final magnesium alumina spinel brick is featured with high refractoriness, superior thermal shock resistance, good temperature vibration, good corrosion resistance at high temperature.
Magnesia Chrome refractory has the similar features to magnesium alumina spinel brick, but the later is more eco-friendly. So magnesium alumina spinel brick can overcome health concerns against chromium containing refractories in various regions worldwide. It also imparts the improved thermal shock resistance normally compared to Magnesia Chrome refractory, but without the potential problem of hazardous waste disposal.
Magnesium alumina spinel brick has low thermal expansion coefficient, so it has excellent thermal shock resistance. The reversible thermal expansion of the spinel is approximately half that of the magnesia.
Magnesium alumina spinel brick has very high strength at both elevated and normal temperature and has no phase transition up to the melting temperature.
The drawback of magnesium alumina spinel brick is that they are more expensive than the conventional magnesite-chrome brick as the raw materials used to make the brick are expensive and some processing costs are high.
Magnesia alumina spinel brick is widely used in transition zone of cement rotary kilns, glass tank regenerators and lime kilns.