Magnesia-iron spinel brick

Magnesia-iron spinel brick is a new type of chromium-free refractory for cement rotary kiln that was first developed in Europe in the late 1990s. The product is made of divalent iron-aluminum spinel (FeO·Al2O3) and high-purity magnesia as the main raw material. During the firing process, the firing temperature and firing atmosphere are strictly controlled to ensure the iron oxide in the brick is FeO. Form exists.
In the process of using magnesium iron spinel brick, a layer of highly viscous calcium-iron and calcium-iron-aluminum compound is formed on the hot surface of the brick, which is easy to hang the kiln skin. Magnesia-iron spinel bricks have high thermomechanical properties and thermochemical properties in addition to the excellent kiln skin properties of magnesia-chrome bricks. In some countries in Europe, it has been widely used in cement rotary kiln firing belts and transition belts, becoming a new type of chromium-free refractory material that is likely to completely replace magnesia chrome bricks. The physical and chemical indicators of the magnesia spinel brick produced by a refractory manufacturer are: MgO86%, Al2O33%, Fe2O38%, CaO1.7%, SiO20.8%, apparent porosity of 15%, bulk density of 3.06g/cm3, The normal temperature compressive strength is 66 MPa, and the high temperature flexural strength (1400 ° C) is 2.5 MPa.

Features:

 (1) During the use process, the hot surface of the brick forms a layer of calcium iron or calcium-aluminum-iron-oxide with high viscosity, which improves the performance of the hanging kiln skin and the firmness of the kiln skin, and is suitable for the protection of lining bricks. Period extension.

(2) The spinel content is high, which not only has high strength but also has excellent thermal shock resistance, and can effectively resist the chemical erosion of cement clinker liquid phase and alkali, sulfur and other gases.

 (3) Spinel and periclase have inconsistent thermal expansion during firing and cooling, and the micro-cracks formed between them can buffer the stress impact caused by temperature changes and avoid brittle bursting of lining bricks.

(4) Chromium-free and environmentally friendly.

Performance:

1. Excellent hanging kiln skin performance

 2. Low thermal conductivity (1000℃, 2.27w/m•k), small thermal expansion coefficient (1000℃, 1..217%);

 3. It has excellent structural flexibility, and has strong anti-erosion and anti-penetration ability to K2SO4, Na2SO4, NaCl, KCl alkali salts decomposed by cement materials.

4. High softening temperature under load, excellent thermal shock resistance, suitable for key parts of SP and NSP kilns with high kiln temperature, fast rotation speed, strong alkali erosion ability and heavy mechanical load, which can effectively prolong the life of the furnace lining and maintain a low Kiln barrel temperature.