Thermal shock resistance physical and chemical properties of Refractory Brick

The thermal shock resistance of refractory brick is the comprehensive performance of their mechanical properties and thermal properties under the conditions of temperature change. Refractory brick subjected to rapid temperature changes, known as thermal shock. Firebrick in the thermal shock generated in the new crack, and the new crack and crack growth caused by the original crack, peeling, fracture and other conditions, known as the firebrick thermal shock damage. Thermal shock damage is the result of thermal stress, refractory bricks in the temperature changes, deformation is suppressed by the stress generated by thermal stress.
Reheat line change of silica brick, thermal stress is produced when the thermal expansion of refractory brick is evenly affected by the temperature gradient, as well as in the phase transition, when different phases are changed in temperature. The thermal stress is proportional to the elastic modulus and elastic strain of the refractory brick, and the modulus of elasticity of the refractory brick is the product of the linear expansion coefficient and the temperature change.
The thermal shock resistance of refractory brick is the ability of refractory brick to resist damage under the conditions of rapid temperature change. Has been said that thermal stability, thermal shock stability, thermal shock resistance, resistance to temperature abrupt change, resistance to abrupt heat,etc, refractory brick in the low temperature and medium temperature is brittle material, the lack of ductility, thermal equipment, refractory Brick is often subjected to drastic temperature changes that cause damage. Thermal shock resistance is one of the important performance properties of refractory brick.
The physical and chemical properties of refractory brick:
Refractory brick is metallurgical ferrosilicon and industrial silicon occurs when the SiO2 and Si gaseous oxygen and oxygen in the rapid condensation of the composition and an ultra-fine silicon powder material. The following describes the physical and chemical properties of refractory brick:
Refractory brick: the appearance of gray Jifen gray ﹑ refractoriness> 1600 ℃. Bulk density: 200 ~ 250 kg / cubic meter.

Which points should be paid attention to when using refractory material？

1.After pouring, if without adequate maintenance, due to the lining body early strength is low, the structure is loose, often too late to sintering has been damaged, lining up abruptly, sometimes burst.

2. The lining thickness of thin body, pouring the space is little, between mold and burner with a lot of cramp, pouring, vibrating, the operation of the vibrator is extremely difficult, operation not skilled or not serious, refractory castable vibrating false.

3.Casting during the construction of the space is little, construction personnel are often more mixing materials with water, to make the refractory castable has good liquidity, but increase the porosity in the refractory lining of the body, reduce the density of the lining body, thus reducing its strength (if refractory castable for chemical combination, add too much liquid binder, same adverse effects) : on the contrary, lining body vibrating close-grained, not also will shorten the service life of refractory castable.

4.When the winter construction, low temperature binder (hydration) hydration incomplete or not hydration, or casting seas, would seriously reduce the strength of the refractory castable or destroy its structure, so as to affect the use effect.

The nature of combination determines high temperature structural strength of Magnesia Brick

Magnesia brick is widely used in steelmaking furnace lining, ferroalloy furnace, mixed iron furnace, non-ferrous metallurgical industry furnace, building material lime kiln, glass industry regenerative room lattice body because of high temperature performance and strong anti-alkali slag ability. Heat exchanger, refractory industry, high-temperature calcining kiln and tunnel kiln. The refractoriness of magnesia brick is as high as above 2000 ℃, and the softening temperature of the load varies with the melting point of the combined phase and the liquid phase produced at high temperature. General magnesia brick load softening start temperature in the 1520 ~ 1600 ℃, while the high-purity magnesium boast a heavy softening temperature of up to 1800 ℃.
Magnesia  brick at 1000 ~ 1600 ℃ under the linear expansion rate is 1.0% to 2.0%, and approximate or linear, refractory products, the thermal conductivity of magnesium specializes in second only to carbon brick, with the temperature rise reduce. Under the condition of water cooling at 1100 ℃, the number of thermal shock of magnesia brick is only 1 ~ 2 times. MgO brick on the CaO and ferrite alkaline slag resistance, but with SiO2 and other acidic slag resistance is weak, and therefore can not be used in direct contact with the silica bricks, generally separated by a neutral brick. At room temperature, the conductivity of magnesia brick is very low, but at high temperature, its conductivity will not be ignored. The performance of magnesium brick, due to the use of raw materials, production equipment, process measures, etc. have a greater difference. Magnesia brick load softening temperature and the collapse of the beginning of the temperature difference is not much difference between this and the silica brick, because the main phase of magnesium bricks is periclase, but the periclase crystals in the magnesia brick is not crystalline network skeleton, but by the binding of the binder.(http://www.magnesiabricks.com/product/magnesia_brick.html)
Therefore, the nature of the combination determines the high-temperature structural strength of magnesia brick. In common magnesia brick, as the combination is generally calcareous olivine and magnesium rose pyroxene and other low-melting silicate phase, although the magnesia brick constitute the higher melting point of the periclase grain, but at about 1500 ℃ melting Of the silicate phase exists, and its liquid phase viscosity at low temperature is very small, therefore, reflects the deformation of ordinary magnesia brick deformation temperature and collapse temperature difference is not large, but with a greater difference in refractoriness. And the softening start temperature of high-purity magnesia brick can reach 1800 ℃, mainly because the combination between the periclase grains is forsterite or dicalcium silicate, and the melting temperature of eutectic with MgO is high , The lattice strength between the crystal and plastic deformation at high temperature is small, crystal particles with good.

The Advantages of Mullite Insulation Brick

Mullite insulation brick has several advantages:
1. Insulating brick without radiation, green, can be widely used in a variety of public buildings and home interior decoration.
2. The installation of cement, saving a lot of material, manpower and time. Reduce the production of cement combustion caused by air pollution, in line with green low-carbon environmental protection requirements.
3. More than 70 carrier life, 20 years of renovation life long, to adapt to climate and complex environment and other fields. Compared to the international aluminum plate, aluminum veneer and steel hanging plate quality, reduce bearing 30% ~ 90%.(http://www.insulatingbrick.com/product/mullite_insulation_brick.html)
4. Double effect, the general shortened period, the comprehensive cost from 30% to 70%.
5. The comprehensive replacement of aluminum-plastic panels, honeycomb panels, curtain wall and other commonly used decorative materials, multi-functional integration, a construction can solve the insulation decorative two functional requirements, smooth and beautiful decorative strong.
6. Insulating brick high strength, good rigidity, anti-seismic, wind, creep resistance, superior performance, reduce construction load, more economical and durable.
7. Flame-retardant, energy-saving insulation, noise, crack waterproof, energy efficiency requirements by building construction design requirements of 65%.

The Advantages of Sillimanite Brick

Sillimanite brick is made of sillimanite refractory brick. The general use of high-temperature combustion and mud casting production.
Sillimanite brick has several advantages:
1. Non-ferrous metal smelting industry application
The use of silicon carbon, high temperature, high strength, good thermal conductivity, impact resistance, high temperature indirect heating materials, such as strong ort furnace. Distillation furnace tower, aluminum cell, copper furnace lining, furnace arc zinc plate zinc powder, thermocouple protection tube
2. Iron and steel industry application
The use of silicon carbide corrosion resistance. Heat shock wear resistance. Good thermal conductivity, suitable for large blast furnace lining, improve service life.
3. Metallurgy and mineral processing industry applications
The abrasion resistance is 5 ~ 20 times of the service life of cast iron, rubber, is the aviation industry, the aviation industry, the aviation industry, the aviation industry, the aviation industry, Track the ideal material.
4. Building material ceramics, wheel industry application
Use thermal conductivity. Heat radiation, high strength, the characteristics of plate kiln furniture, not only can reduce the carrying capacity of kiln furniture, kiln can also improve the carrying capacity and product quality and shorten the production cycle, is the ideal indirect ceramic glaze sintering sintering material.

The Nature of Conjugate Determines the High Temperature Structural Strength of the Magnesia Brick

Because of the good high temperature performance and strong alkali slag resistance of the magnesia brick, it is widely used in steelmaking furnace lining, ferroalloy furnace, metal mixer, nonferrous metallurgical industry furnace, lime kiln building material, glass industry regenerator heat exchanger grid Lattice, high temperature calcined kiln and tunnel kiln refractory industry. The fire resistance of the magnesia brick is above 2000 ℃, the fire resistance under load is equal to the melting point of the combined phase, and the liquid phase result is changed at high temperature. Generally, the softening temperature of load of magnesia brick is 1520 ~ 1600 ℃.
Magnesia brick at  the 1000 ~ 1600 ℃ linear expansion rate is generally 1.0% to 2.0%, in refractory products, the thermal conductivity of magnesia brick after carbon brick, with the temperature decreases. In the 1100 ℃ water cooling conditions, the number of magnesia brick thermal shock is only 1 to 2 times. MgO brick has a strong basic slag resistance to CaO and ferrite, but the weak acid slag has strong resistance to SiO2, so it is not used in direct contact with silica brick, and is generally separated by neutral brick. At room temperature, the magnesia brick is very low in conductivity, but at high temperatures, the conductivity is not negligible. The performance of magnesia brick, due to different raw materials, production equipment, technical measures, there is a big difference. The difference between the starting temperature and the collapse temperature of the magnesia brick is not so big as that of the silica bricks because the main phase composition of magnesia bricks is periclase and the periclase crystals are not the crystalline network skeleton , But by combination gluing.(http://www.magnesiabricks.com/product/magnesia_brick.html)
Therefore, the combination of the nature of the magnesium brick determines the high-temperature structural strength. In ordinary magnesium bricks, although the magnesite grains of magnesium olive bricks have a higher melting point, there is a molten silicate phase of about 1500 ° C, and the viscosity of liquid phase viscosity at high temperature is very small, so the load deformation temperature And the collapse temperature is not big, but with the difference of stainless steel is bigger. The starting temperature of the high-purity magnesia-magnesia bricks can reach 1800 ℃, mainly because the periclase is a combination of forsterite or dicalcium silicate, the melting temperature of the eutectic solution is high, the formation of MgO is high, and the intensity between the lattices is large , Plastic deformation at high temperature is small, a good combination of crystalline particles.

The Performance of Chrome Corundum Brick

The performance of chrome corundum brick.

Fire resistance of the products

Add Cr2O3 to high purity corundum material, no matter how much the amount is, not only will not reduce refractory performance of materials, on the contrary make fireproof performance of materials improved. The refractoriness of chrome corundum brick (> 1790!) and refractoriness under load (> 1700!) are superior to high purity corundum products.

1. The strength of the products

 Room temperature compressive strength of high purity corundum brick is 70 ~ 100 MPa commonly, room temperature compressive strength of high performance chromecorundum brick is generally more than 150 MPa, the intensity is significantly higher than the corundum brick. This is because the products in the process of burning, between particles and particles, particles and fine powder, powder and powder, formed  Al2O3 - Cr2O3 solid solution, the solid solution connects particles to fine powder particles together, make the strength of the material is greatly increased.

2. Thermal shock resistance

Add Cr2O3 to corundum, when Cr2O3 content is 10% ~ 66%. The raw materials that Chrome corundum series of products used is made from alumina and chromium oxide according to certain proportion matching, after high temperature melting synthesis of a solid solution. Using special refractory materials production technology to produce refractory brick, can improve and enhance internal quality of the products, improve the high temperature performance of products, have the characteristics of high refractoriness, big strength, good thermal shock stability, strong ability to resist erosion, in use, scour resistance, wear resistance, erosion resistance, spalling structure resistance, have obtained the good effect in metallurgy, glass, carbon black, the petrochemical industry.