Anti-stripping high alumina brick

The principle of anti-spalling resistance of high-alumina bricks is to improve the ability to resist crack generation and crack propagation. The commonly used technology for anti-stripping high alumina bricks is to add raw materials with different expansion coefficients to the ingredients. Due to thermal expansion mismatch, cracks are left in the product after burning. The main raw materials added are kyanite, sillimanite and zircon. Lanpinite decomposes at 1325-1350℃, completes the decomposition at 1450℃, and expands by 16%-18% in volume; sillimanite decomposes at 1500℃, expands in volume by 8.4%, andalusite decomposes at 1400℃, decomposes at 1500℃, and expands in volume 3.29%. The toughening of zircon is achieved by the crystal transformation and mullite effect of tetragonal zirconia and monoclinic zirconium. Appropriate addition of zircon raw materials to high alumina bricks can greatly improve its wear resistance and anti-stripping performance.

Features

(1) It has good high temperature resistance and strong corrosion resistance;

(2) It has certain mechanical strength, friction resistance and good thermal shock resistance;

(3) Long service life.

Anti-peeling mechanism of high alumina anti-peeling brick

Anti-stripping high alumina bricks use high alumina bauxite as the main raw material, introduce a small amount of ZrOz (due to the phase transition between monoclinic and tetragonal ZrO2, which can improve the thermal shock stability of the product), add a certain amount of composite binder and Additives, by controlling the particle gradation of the mud, the refractory bricks made by molding and high-temperature firing become anti-stripping high-alumina bricks.

The anti-stripping mechanism is due to the microstructural characteristics of ZrO2, which determine the anti-stripping performance.

①There are obvious micro-cracks around the ZrO2 aggregate, and the aggregate has obvious gap peeling with the surrounding corundum and mullite.

② The well-developed ZrOz aggregates are columnar and form a layered distribution in space. There are small slits between ZrO2, the size of which is only 1-5 μm, forming a channel structure. This structure is superimposed with superimposed layers, tortuous and tortuous, which is conducive to stress transmission and dispersion.

③ Mullite is well-developed and fibrous, and interlaces with ZrO2 and corundum in space to form a composite reinforcing structure. Obviously, when ZrSiO4 decomposes at high temperature, it reacts with surrounding Al2O3 to form ZrO2 and mullite. The existence of ZrO2 crystals prevents the growth of fibrous mullite crystals and platy corundum, and is wrapped by them, so it is surrounded by ZrO2. Chaos state.

④The petrographic analysis shows that the structure of corundum and mullite is staggered, ZrO2 is intercalated, there are microcracks around, and the larger ZrO2 crystal itself and its surroundings have radial microcracks.

The above structure has the effect of dissipating energy when subjected to stress and improving thermal stability and high temperature strength.

Anti-spalling high-alumina bricks should have a high softening temperature under load, good high-temperature structural properties, good thermal shock stability, strong resistance to cement clinker erosion, and excellent resistance to spalling, alkali corrosion, and low thermal conductivity.

Anti-spalling high alumina composite brick is a fired product made of super high alumina bauxite clinker and ZRO2-containing synthetic material as raw materials, and is made by high pressure molding according to a certain proportion. The product has strong anti-spalling ability and potassium resistance , Na, sulfur, chlorine and alkaline salt erosion, low thermal conductivity and other properties, is an ideal material for the transition zone and decomposition zone of cement kiln, the product is characterized by good thermal shock resistance, strong ability to adapt to the environment. It is mostly used in rotating preheating belts or in decomposition furnaces and grate coolers.

Performance advantages:

1. Reduce the temperature of the cylinder by more than 50 °C to ensure the safe operation of thermal equipment and reduce the phenomenon of red kiln.

2. Improve the heat utilization efficiency of rotary kiln, reduce energy consumption by more than 5%, and improve enterprise efficiency.

3. The overall performance is good, the effective use volume is larger than that of composite products, and the anti-wear cycle is long.

4. When the product is worn to half, the composite product will not be able to be used, while the heat-insulating silicon corundum brick can stick to the remaining one-third.