The reason for surface cracks of refractory bricks after used a period of time

Although the fire brick is good, the structure is relatively stable, but the  refractory  brick used for a period of time, some customers reflect the surface of the refractory brick cracks, which is what causes it? After many years of research and experience, the main reason is that the surface of the refractory brick is four points. Today’s technical staff for you to read.

1, the raw material itself is dry and sensitive coefficient

The drying coefficient of raw material is the possibility of cracking of the product, the higher the drying coefficient is, the more easily the product is cracked, the lower the coefficient is, and the more difficult the product is. So we must be careful when choosing raw materials, as far as possible to choose dry sensitive coefficient of raw materials.

2, inappropriate production measures

Production without attention to the ratio of raw materials, if the mix is not uniform will cause the product crack, which requires us to pay attention in the production of the source, to avoid cracking in the future.

3, dry reasons

The air temperature is too high, and the furnace preheating is too short and the ventilation quantity is too large, so the reason of the crack is caused by the fire.

4, roasting reasons

A gate is not reasonable, the fire cooling too fast, too fast, will lead to uneven heating, it will cause cracks in refractory brick.

Above brick appear on the surface of the crack by Xinmi Changxing refractory to provide you with, more on the refractory brick consulting; please pay attention to our website.

Clay bonded castable refractories

Clay bonded castable refractory system combined with clay (i.e. soft clay as binder, its working principle is by clay alkali replacement given construction, high temperature is formed ceramic combination, and generates acicular mullite, interspersed with each other, compact structure,
high temperature and good performance.

Clay alkali replacement is in the mud and clay, when adding a thicker water film of metal ion, hydrogen ion replacement clay colloid diffusion layer, the diffusion layer thickness, increase the potential, increase the clay particles are negatively charged and improve the fluidity of the slurry can be poured to construct; when adding metal ions with thin water film, replacement of water film thickness of metal ions, the role and the opposite, the fluidity of the slurry and reduce the flocculation, resulting in clay bonded castable hardening. The former, commonly known as the glue solution or water reducing agent is widely used substances containing sodium ions, such as sodium tripolyphosphate; the latter, known as flocculent and coagulant, general use of lime and Portland cement, aluminates cement and magnesium hydroxide containing substances of calcium and magnesium ions.

It should be pointed out that when the clay bonded with the refractory castable is prepared, the adhesive agent and coagulant are added simultaneously and interact with each other. In order to make clay solution of glue and convenient construction and promoting hardening and the formation of strength, so we should choose delayed coagulant and dosage should be appropriate.

Clay bonded castable refractory material is mainly used in heating furnace, soaking pit and iron ditch and other thermal equipment, and display the superiority. However, its normal temperature and pressure strength is low, and the dry strength is not high. To this end, in the preparation of clay with refractory cast material, mixed with a small amount of advanced refractory superfine powder and other additives, made of high strength clay bonded with refractory. In addition, it is also developed to combine with the light of the light refractory, and can be used directly in the working layer of the flame furnace.

How to control the volume stability of refractory materials

Because of the non setting refractory material is used in the field of baking and burning, will appear dry shrinkage and firing shrinkage.

It is necessary to consider the measures to compensate the shrinkage in the design ofcomposition, that is, the total molar volume of the reaction product is greater than the total molar volume of the reaction product, and the volume expansion of the matrix is matched with the sintering shrinkage. The main methods are as follows:

(1) Thermal decomposition method, a mineral which is decomposed at high temperature and the molar volume of the product of its in situ thermal decomposition is more than the molar volume of the original mineral to compensate for the sintering shrinkage of the material. Such as in the A1203-SiO2 system unshaped refractory materials added a certain amount of kyanite, after high temperature calcinations into mullite and free silica (quartz), volume expansion and produces about 16% ~ 18% (calculated). There are sillimanite, andalusite and sillimanite minerals. The volume expansion after the decomposition of Kyanite is the largest, so it has been widely used.

(2) High temperature chemical reaction method is used to compensate for the volume expansion effect of the in-situ chemical reaction occurring during high temperature use. In the aluminum matrix such as magnesium or magnesium aluminum castables, ramming material or vibratory ramming material in. With high temperature MgO and in situ reaction to generate spinel and produce about 7.5% of the volume expansion, can be part of the compensation of the sintering shrinkage.

(3) In the process of heating, the transformation method of the crystal type can be used to produce the mineral, and the molar volume of the crystal is larger than the molar volume of the transformation. As in the trough of blast furnace A1203- SiC-C matter ramming material is added with appropriate amount of silica particles with quartz transformation of tridymite and cristobalite volume expansion effect (respectively 12.7% and 17.4% to compensate matrix of sintering shrinkage, reduce or eliminate the trough of the shrinkage cracking phenomenon.

Recovery and utilization of flue gas and heat in the production of refractory materials

Because of the kiln body structure and the thermal process of different, the intermittent kiln is more than 5 times higher than the flue gas produced by the tunnel kiln. In general, the higher the gas temperature, the greater the proportion of heat loss. Such as gas temperature of 1093, the heat loss of 55%, when the gas temperature of 1427 degrees, the heat loss was 70%. For hot gas intermittent sintering refractory down draft kiln, according to the relevant experimental data show that: heat from the flue gas from the furnace kiln accounted for about 35% to 40% of all caloric expenditure, in the absence of any heat recovery measures, the calculation results of heat balance, heat efficiency is in 10% ~ 15%This is a great loss of heat. Therefore, the use of gas heat is a very important energy recovery work.

Setting heat exchanger in the flue is an important method for waste heat recovery. Hot air through a heat exchanger obtained can be directly sent to the burner for combustion supporting air, can also be hot air diluted transported to the products of somatic embryos drying kiln drying medium or it, the kiln thermal efficiency reached 30% or higher.

When firing system by changing the preheated air to the heat exchanger, and the hot air do combustion the combustion air can not only increase the kiln thermal efficiency, reducing the consumption of fuel, energy-saving effect is achieved. And it can increase the temperature of the flame, increase the heating efficiency, and shorten the heating time (the period). And because of the volume expansion of hot air, the flow velocity of the burner is increased, the gas flow in the kiln is accelerated, and the temperature in the kiln is uniform. The relevant data shows that the fuel consumption can be reduced from 6% to 8% when the air temperature is 220 ~ 250. At the same time the combustion air of different temperatures, a very large impact on the flame temperature. Even in the case of no preheating gas, combustion temperature of gas increases significantly with increasing the preheating temperature of combustion air. Refractorymaterials not only can solve the problem of low firing temperature, but also plays an important role in the enterprise energy saving and reducing consumption.

Ten properties of light brick

1, capacity light: light brick its dry capacity is only 500-700Kg/m*3, is ordinary concrete 1/4, clay 1/3, hollow block 1/2, due to its bulk density than water, commonly known as floating on the surface of aerated concrete, the use of this product in the building, can reduce the weight of buildings, greatly reduce the overall cost of building.

2, heat preservation and heat insulation: because of the air entrained concrete in the manufacturing process, the internal form a tiny hole, these holes in the material to form the air layer, greatly improve the insulation effect, so that the thermal conductivity of aerated concrete is 0.11-0.16W/MK. Heat preservation effect is 5 times of clay brick, 10 times of ordinary concrete.

3, sound absorption, sound insulation: aerated concrete porous structure made it a good sound absorption, sound insulation performance, you can create a high air tightness of indoor space. Provide a quiet and comfortable living environment.

4, small shrinkage: due to the use of high quality river sand and powder coal as a silicon material, the shrinkage value is only 0.1–0.5mm/m, the value of the small shrinkage of fine material to ensure that your wall will not crack.

5, non permeability: the product of the pore structure, so that the capillary effect is poor, water absorption of wet slow, with the volume of water to the saturated time is 5 times the clay firebrick.

6, environmental protection: manufacturing, transportation, use of the process without pollution, protection of arable land, energy saving, is a green building materials.

7, earthquake: the same building structure using light brick than the clay brick to improve the seismic level.

8, durability: aerated concrete long-term strength and stability, in the test piece of atmospheric exposure to a year after the test, the intensity increased by ten, 25% years after still remain stable.

9 and processing: This product is light weight. Size specifications are various, convenient nail, drilling, cutting, sawing, planning engrave the laying of pipelines and on the wall use expansion tube can directly fixed condole cabinet, air conditioning, Shan machines and other, to your water and electricity installation, home decoration convenience.

10, fire: fire resistance to 700 degrees, for a class of refractory, 100mm thick block fire performance of 225 minutes, 200mm thick block fire resistance performance of 480 minutes.

Ten properties of light brick

1, capacity light: light brick its dry capacity is only 500-700Kg/m*3, is ordinary concrete 1/4, clay 1/3, hollow block 1/2, due to its bulk density than water, commonly known as floating on the surface of aerated concrete, the use of this product in the building, can reduce the weight of buildings, greatly reduce the overall cost of building.

2, heat preservation and heat insulation: because of the air entrained concrete in the manufacturing process, the internal form a tiny hole, these holes in the material to form the air layer, greatly improve the insulation effect, so that the thermal conductivity of aerated concrete is 0.11-0.16W/MK. Heat preservation effect is 5 times of clay brick, 10 times of ordinary concrete.

3, sound absorption, sound insulation: aerated concrete porous structure made it a good sound absorption, sound insulation performance, you can create a high air tightness of indoor space. Provide a quiet and comfortable living environment.

4, small shrinkage: due to the use of high quality river sand and powder coal as a silicon material, the shrinkage value is only 0.1–0.5mm/m, the value of the small shrinkage of fine material to ensure that your wall will not crack.

5, non permeability: the product of the pore structure, so that the capillary effect is poor, water absorption of wet slow, with the volume of water to the saturated time is 5 times the clay firebrick.

6, environmental protection: manufacturing, transportation, use of the process without pollution, protection of arable land, energy saving, is a green building materials.

7, earthquake: the same building structure using light brick than the clay brick to improve the seismic level.

8, durability: aerated concrete long-term strength and stability, in the test piece of atmospheric exposure to a year after the test, the intensity increased by ten, 25% years after still remain stable.

9 and processing: This product is light weight. Size specifications are various, convenient nail, drilling, cutting, sawing, planning engrave the laying of pipelines and on the wall use expansion tube can directly fixed condole cabinet, air conditioning, Shan machines and other, to your water and electricity installation, home decoration convenience.

10, fire: fire resistance to 700 degrees, for a class of refractory, 100mm thick block fire performance of 225 minutes, 200mm thick block fire resistance performance of 480 minutes.

Ten properties of light brick

1, capacity light: light brick its dry capacity is only 500-700Kg/m*3, is ordinary concrete 1/4, clay 1/3, hollow block 1/2, due to its bulk density than water, commonly known as floating on the surface of aerated concrete, the use of this product in the building, can reduce the weight of buildings, greatly reduce the overall cost of building.

2, heat preservation and heat insulation: because of the air entrained concrete in the manufacturing process, the internal form a tiny hole, these holes in the material to form the air layer, greatly improve the insulation effect, so that the thermal conductivity of aerated concrete is 0.11-0.16W/MK. Heat preservation effect is 5 times of clay brick, 10 times of ordinary concrete.

3, sound absorption, sound insulation: aerated concrete porous structure made it a good sound absorption, sound insulation performance, you can create a high air tightness of indoor space. Provide a quiet and comfortable living environment.

4, small shrinkage: due to the use of high quality river sand and powder coal as a silicon material, the shrinkage value is only 0.1–0.5mm/m, the value of the small shrinkage of fine material to ensure that your wall will not crack.

5, non permeability: the product of the pore structure, so that the capillary effect is poor, water absorption of wet slow, with the volume of water to the saturated time is 5 times the clay firebrick.

6, environmental protection: manufacturing, transportation, use of the process without pollution, protection of arable land, energy saving, is a green building materials.

7, earthquake: the same building structure using light brick than the clay brick to improve the seismic level.

8, durability: aerated concrete long-term strength and stability, in the test piece of atmospheric exposure to a year after the test, the intensity increased by ten, 25% years after still remain stable.

9 and processing: This product is light weight. Size specifications are various, convenient nail, drilling, cutting, sawing, planning engrave the laying of pipelines and on the wall use expansion tube can directly fixed condole cabinet, air conditioning, Shan machines and other, to your water and electricity installation, home decoration convenience.

10, fire: fire resistance to 700 degrees, for a class of refractory, 100mm thick block fire performance of 225 minutes, 200mm thick block fire resistance performance of 480 minutes.