Characteristics of Cordierite Bricks and Kiln Furniture Cordierite Bricks

Cordierite bricks and kiln furniture: Cordierite bricks are a type of refractory material with cordierite (2MgO·2Al2O3·5SiO2) as its main component. Pure cordierite contains 13.7% magnesium oxide (MgO) and has the following characteristics: a low coefficient of thermal expansion of 3×10⁻⁶/℃. Due to its low coefficient of thermal expansion, cordierite materials generally exhibit excellent thermal shock resistance.

Pure cordierite is an expensive material, so lower purity semi-cordierite materials are often used as substitutes. Semi-cordierite materials also exhibit a low coefficient of thermal expansion.

Semi-cordierite materials are frequently used as kiln furniture, kiln car fixing blocks, and ceramic components in ceramic kilns. In some cases, alumina-silicate materials are also used for the same product applications. Table 7 lists the characteristics of some semi-cordierite products used for kiln furniture/kiln blocks. The maximum service temperature of these products is typically 1200℃ or higher.

Table 7 shows the relationship between magnesium oxide content and the coefficient of thermal expansion. When the magnesium oxide content is very low, the coefficient of thermal expansion is close to that of clay bricks or mullite [approximately 6 × 10⁻⁶/℃]. Figures 5 and 6 show the microstructure of such typical products.

Figure 5: Microstructure of hemicordierite extruded into pyrophyllite

Figure 6: Microstructure of clay-based hemicordie bricks

The microstructure of cordierite exhibits "crack-like" pores, a typical characteristic of extruded clay products (Figure 5). The large size of the pyrophyllite aggregate particles, sometimes approaching 3 to 4 mm, is not clearly visible in this micrograph. In contrast, the microstructure of pressed cordierite shows that the refractory aggregate particles are surrounded by a sintered clay matrix, with predominantly circular pores (Figure 6). Many experts believe that the presence of fine circular pores improves thermal shock resistance. Therefore, pressed products with approximately 0.9% MgO content (Table 7) may have similar properties to extruded products with 3.0% MgO content.

A typical impurity in cordierite bricks is quartz, which is converted from "free" silica (SiO2) or quartz in the raw materials when the refractory is fired at a temperature of at least 1300°C. By referring to the MgO-Al2O3-SiO2 phase equilibrium diagram (not shown), it can be seen that free cristobalite is an equilibrium phase unless the product composition is exactly the same as pure cordierite. Excessive cristobalite content can lead to "caking" and reduce the lifespan of kiln furniture/kiln blocks. Crizobalite can be conveniently determined using X-ray diffraction (XRD) or thermal analysis (TA) techniques.

Requirements for Refractory Castables in Various Parts of CFB Circulating Fluidized Bed Boilers

Circulating fluidized bed boilers are currently the most widely used and relatively environmentally friendly waste heat boilers in China. They are primarily used in the power industry, petrochemical industry, waste incineration industry, and other sectors. While their applications vary, their structure is largely the same. During boiler operation, high-temperature gases and solid particles in the gases cause severe wear on the refractory linings in various areas, including the furnace and circulation system. Therefore, the wear protection and thermal insulation requirements of these linings are critical to boiler operation. Taking power plant boilers as an example, the operating environment of various boiler components and the requirements for the refractory castable lining are as follows.

Lower Furnace

The dense phase area in the lower furnace is a highly wear-prone area in circulating fluidized bed boilers. The material within this area is coarse, highly concentrated, and fluidized at high speeds. The combustion atmosphere is somewhat corrosive. The wear-resistant refractory castable used in this area must be wear-resistant, have good thermal conductivity, and exhibit excellent resistance to thermal cracking and thermal shock. Steel fiber wear-resistant refractory castables are recommended.

Separator Inlet Flue Duct

The separator inlet flue duct experiences a change in airflow direction, resulting in fine ash particles and a high concentration. The airflow velocity is generally 4.5-6.0 m/s, and the temperature is 850-950°C. The combustion atmosphere is oxidizing, resulting in severe wear and erosion. The castable must exhibit excellent wear resistance, thermal cracking, and thermal shock resistance. Steel fiber wear-resistant refractory castables are recommended.

Cyclone Separator

The high airflow velocity within the cyclone separator causes centrifugal force, causing coarse particles in the airflow to collide with the wall and separate. This results in severe wear at the separator inlet and on the inner wall of the separator. The operating temperature within the separator is less than 1000°C, and the refractory and wear-resistant layer is relatively thick. The atmosphere is oxidizing. The castable must be lightweight, dense, wear-resistant, and have excellent thermal insulation (for adiabatic separators), as well as good resistance to thermal cracking and thermal shock. High-strength, wear-resistant, and refractory castables or wear-resistant, refractory plastics are recommended.

Return Material Transfer Unit

The return material transfer unit transports ash separated by the separator into the furnace for recirculating combustion. The return material transfer unit features a fluidized bed on one side of the furnace and a moving bed on the other. It is a fluidized, sealed ash conveying device. The fluidization velocity is less than 1 m/s, and the material inside is fine and highly concentrated. The operating temperature is approximately 900°C. Compared to other parts, the return material transfer unit's operating environment is not particularly adverse, but construction is challenging. Since combustion does not occur within the return material transfer unit, the castable must possess excellent thermal insulation, thermal cracking, and thermal shock resistance. High-strength, wear-resistant, and refractory castables are recommended.

Platenose Heating Surfaces

Power plant boiler furnaces feature platenose heating surfaces (water-cooled platen and superheater). The lower elbow of the platen is subject to wear and tear from ash particles. This requires the castable to exhibit excellent wear resistance and thermal conductivity. High-strength, wear-resistant, and refractory castables are recommended.

Precautions for High-Strength Wear-Resistant Castable Construction

The quality of high-strength wear-resistant castable construction directly determines its wear resistance and service life. Key considerations lie in controlling the water-cement ratio, ensuring density, and maintaining proper maintenance to prevent cracking and shedding caused by improper construction. Specific precautions can be divided into four key stages:

Refractory Castables in Various Parts of CFB Circulating Fluidized Bed Boilers

1. Pre-construction Preparation: Clean the base surface to remove oil, dust, and loose debris. Sandblast and roughen as necessary. Install anchors according to design requirements, ensuring uniform spacing (usually 150-200mm). Secure with welds and apply anti-rust paint.

2. Mixing: Use a forced mixer. First, add the dry castable and mix for 2-3 minutes. Then, strictly control the amount of water added according to the instructions (generally a water-cement ratio of 0.10-0.14). Mix until a uniform, lump-free paste forms. The mixing time should be minimal (5-8 minutes total). Avoid initial setting.

3. Casting Process: Use an inserted vibrator (30-50mm diameter) to vibrate the lining layer by layer, with each layer no thicker than 300mm. Vibrate until the slurry is smooth and free of bubbles, avoiding missed or over-vibration. Casting should be continuous, with the interval between each layer no longer than the initial setting time to prevent cold joints.

4. Curing and Baking: Cover with plastic sheeting or wet burlap for 12 hours after casting, maintaining an ambient temperature of 5-35°C for at least 7 days. After curing, bake slowly according to a heating curve to remove moisture and avoid cracking caused by rapid heating. Baking time varies depending on the thickness of the lining and generally takes 3-7 days.

Effect of α-Al2O3 on the Properties of Aluminum-Chrome Bricks Made of Chromium-Containing Slag

Aluminum-chrome bricks containing chromium slag. The aluminum-chrome bricks with an aluminum-chrome slag addition amount (wt) of 30% were used as reference samples, and the formula was set as the basic formula. On this basis, 1wt%, 2wt%, 3wt%, and 4wt% of α-Al2O3 were added respectively, and the increased amount replaced the brown corundum fine powder, keeping the Cr2O3 content unchanged, and exploring the effect of α-Al2O3 on the performance of aluminum-chrome bricks containing chromium slag.

Performance of Aluminum-Chrome Bricks

After the raw aggregates were dry-mixed in a small wet mill for 3 minutes, about 3% of the binder (aluminum dihydrogen phosphate solution) was added. After mixing for 1 minute, the machine was stopped, and fine powder was added to continue mixing. Continue to add binder until the mud is suitable, and the total amount of binder added is about 3.5%. After fully mixing, the material is discharged and loaded into a woven bag lined with a plastic bag. Then the trapped material was sealed for 12 hours and formed on a 630-ton electric press. The molded blank sample is a standard brick (230×114×65mm). The formed wet bricks enter the tunnel drying kiln and are kept warm and dried at 110℃~120℃ (>12 hours). After drying, they are loaded with the loading method with the width direction as the pressure direction. They are heat treated in a 111m long ultra-high temperature tunnel kiln fueled by natural gas. The firing system is 1600℃×4.5h.

According to relevant standards, the bulk density, apparent porosity, compressive strength, linear change rate after firing, load softening temperature and thermal shock stability (1100℃ water cooling) of the samples are tested, and the performance indicators of each experimental brick are tested.

Effect of α-Al2O3 on the performance of aluminum-chrome bricks containing chromium slag

The effect of α-Al2O3 micropowder addition (wt.%) on the volume density, apparent porosity, compressive strength and post-firing linear change rate of aluminum-chrome bricks containing aluminum-chrome slag. With the increase of α-Al2O3 micropowder addition, the apparent porosity decreased, the volume density increased, but the amplitude was not large; the compressive strength tended to increase, but the amplitude was not large. The post-firing linear change rate is gradually decreasing, and the comprehensive effect is better when the α-Al2O3 micropowder is added at 3wt%. This is because the basic mechanism of micropowder is ST filling. Appropriate micropowder is filled in the micropores of refractory aggregate and fine powder, which can increase its volume density and reduce apparent porosity. In corundum products, adding α-Al2O3 micropowder can promote sintering and reduce the sintering temperature.

Since the brown corundum and aluminum-chromium slag used in the raw materials are both electro-melting materials, and the South African chromium ore are both raw materials with high volume density and low apparent porosity, the change rate of the product during the sintering process is very limited. Although the addition of α-Al2O3 micropowder has a certain improvement on the conventional performance, the impact is relatively small. When the addition amount is 3wt%, the filling effect is more obvious, and the performance will be reduced if the addition amount is further increased. This has a certain relationship with the overall particle grading of the product.

Effect of α-Al2O3 on load softening temperature. The addition amount of α-Al2O3 micropowder has almost no effect on the load softening temperature, which is due to the high grade of the raw materials of the product itself. The load softening temperature of the reference sample itself is ≥1700℃. The addition of α-Al2O3 micropowder has the effect of promoting sintering. After sintering, it mainly forms high-melting-point mineral phases such as corundum or aluminum-chromium solid solution. Therefore, it will not reduce the load softening temperature of the product.

Effect of α-Al2O3 addition amount (wt.%) on thermal shock stability As the amount of α-Al2O3 powder added increases, the thermal shock stability of the product is not greatly affected. However, when the amount added is 4wt%, the thermal shock stability decreases. This is because as the volume density of the product increases, the apparent porosity decreases, and the denser structure reduces the thermal shock stability of the product. Therefore, it is more appropriate to add α-Al2O3 powder within 3wt%.

What are the Main Products of Corundum Brick Shaping?

Corundum refractory products, Al2O3 98% or more, self-bonded solid phase sintered high-purity corundum brick products, the bonding phase is mainly corundum, and there is a small amount of mullite, etc. Mainly used in petrochemical industry gasification furnace, carbon black reactor, gasification furnace, ammonia decomposition furnace, two-stage reforming furnace, high temperature and ultra-high temperature kiln in refractory ceramic industry, blast furnace in metallurgical industry, etc.

Rongsheng Corundum Bricks

Corundum Bricks Shaped Products

Modified high alumina bricks

①Low creep high alumina bricks: For high alumina bricks with a creep temperature of 1500℃-1550℃, adding some fused corundum and silica raw materials can produce low creep rate high alumina bricks.

②Phosphate bonded high alumina bricks: Special-grade or first-grade high alumina bauxite clinker is used as the main raw material, and phosphoric acid solution or aluminum phosphate solution is used as the binder. A small amount of fused corundum, mullite, etc. is added to strengthen the matrix. Chemically bonded refractory products made by heat treatment at 400-600℃. Mainly used in ironmaking hot blast furnaces, cement kilns, electric furnace tops, ladles, etc.

Corundum mullite bricks

Use fused white corundum, plate-shaped corundum, fused mullite and other raw materials. After batching, mixing, high-pressure molding, and firing in a high-temperature kiln. The main crystal phase of corundum mullite brick products is corundum, and the bonding phase is mullite. Corundum mullite bricks are mainly used in high-temperature firing kilns and kiln tools such as push plates and firing plates in the ceramic industry.

Plate-shaped corundum mullite brick

Plate-shaped corundum mullite brick is made of plate-shaped corundum as the main raw material and mullite as the auxiliary raw material. It is made by adding appropriate amounts of high-purity alumina, ultrafine silicon oxide powder and additives. It is strongly pressed and formed by a 300t friction press and fired at high temperature in an oxidizing atmosphere. Plate-shaped corundum mullite brick can be used for a long time in a high temperature environment of 1700 degrees. Characteristics of plate-shaped corundum mullite brick:

(1) The Al2O3 of plate-shaped corundum mullite brick is ≥82%, which has good high temperature resistance, high refractory temperature, and load softening temperature as high as 1700 degrees.

(2) Resistant to chemical erosion, with strong resistance to acidic solutions or slag.

(3) The Fe2O3 content in plate-shaped corundum mullite brick is ≤0.5%, which is resistant to oxidation. It is not easy to react chemically with gases such as O2, H2, and CO.

(4) Good thermal stability, high temperature volume stability, and not easy to expand or shrink.

(5) Good thermal shock resistance, 1100℃ water cooling ≥30 times, resistant to rapid cooling and heating, not easy to peel off.

(6) High compressive strength at room temperature, ≥ 85 MPa, not easy to wear during transportation or unloading.

Physical and chemical indicators of plate-shaped corundum mullite bricks

Project indicators Al2O3, %≥82Fe2O3, %≤0.5Load softening temperature, ℃1700 (0 deformation) Thermal shock stability, times, 1100℃ water cooling ≥30 Normal temperature compressive strength, MPa≥85 Creep rate, %, 1450℃×50h-0.05 High temperature flexural strength, MPa, 1450℃×0.5h≥10

Application of plate-shaped corundum mullite bricks

Plate-shaped corundum mullite bricks can directly contact flames, resist peeling, and resist high temperatures. It can be used as the thermal insulation lining of high-temperature industrial furnaces and as the working layer of other industrial high-temperature kilns. It is mainly used in petrochemical industry, large and medium-sized synthetic ammonia gasification furnaces and magnetic material gas furnace materials, high-temperature industrial kiln supporting facilities materials, etc. Rongsheng Refractory can customize refractory bricks and products of various materials and shapes according to the customer's high-temperature equipment requirements.

Advantages and Disadvantages of Silicon Carbide Refractory Castables

Rongsheng Refractory Manufacturer, solutions for high temperature industrial furnace lining refractory materials. Advantages and disadvantages of silicon carbide refractory castables. In the field of amorphous refractory materials, silicon carbide refractory castables have always been a product that has attracted much attention. Whether from raw materials to research and development, or from production to use, it is a product that users love and hate. Understanding the advantages, disadvantages and why silicon carbide refractory castables can resist slag erosion can help companies make better choices.

Advantages and disadvantages of silicon carbide refractory castable products

The biggest advantage of silicon carbide refractory castable is that it has high thermal conductivity, low thermal expansion, and does not react with slag. It has been used in kiln parts with severe slag reaction and high-temperature spalling since a long time ago.

Rongsheng Silicon Carbide Refractory Castables

The biggest disadvantage is that the chemical properties are very unstable in certain atmospheres. It is easily corroded in oxidizing gases such as (oxygen, water vapor, carbon monoxide, carbon dioxide), iron oxide, etc., and easily oxidized and decomposed in molten iron and vacuum. Another disadvantage is that silicon carbide refractory castables have poor water solubility. In water-based amorphous refractory materials such as castables, the poor fluidity sometimes causes the poor density of silicon carbide refractory castables. The third disadvantage is the lack of sintering and difficulty in obtaining high strength, but sometimes it is difficult to produce over-sintering and shrinkage, which is a strength in amorphous refractory materials.

Why is silicon carbide refractory castable resistant to slag erosion?

When considering the slag resistance and slag resistance of silicon carbide refractory castable, the following aspects must be considered comprehensively: (1) wettability to slag (contact angle) (2) slag invasion (3) reactivity with slag (4) melting point and viscosity of reaction products. Considering these four aspects, although alumina refractory materials are materials that easily react with slag, as raw materials of refractory materials, they are not materials with poor slag resistance. This is because there are not many low-melting point compounds generated by reaction with slag.

The reason why silicon carbide refractory castable is difficult to be wetted by slag is because of the material of silicon carbide itself. SiC has two crystal forms, α and β, and the crystal structure of β-SiC. Among them, α-SiC has about 120 polymorphs such as 4H, 15R and 6H, among which 6H polymorph is the most widely used in industry. In 6H-SiC, Si and C are stacked alternately in layers, the distance between Si layers or C layers is 2.5Å, and the atomic distance between Si-C is about 1.9Å. There is a certain thermal stability relationship between the various forms of SiC, and the α β crystal forms also transform into each other. When the temperature is below 1600℃, SiC exists in the form of β-SiC. When the temperature is higher than 1600℃, β-SiC slowly transforms into various deformation forms of α-SiC (4H, 15R, 6H, etc.) by recrystallization. For α-β transformation, higher pressure is required, while for β-α transformation, only lower pressure is required. The transformation between various types of silicon carbide does not produce volume effect. SiC is a compound with strong covalent bonds. It still maintains high bonding strength at high temperatures, so SiC has high hardness, large elastic modulus, excellent wear resistance, and will not be corroded by most acid and alkali solutions. For the intrusion of slag and the melting point generated after reaction with slag, when compared with oxides, the slag resistance is significantly better.

When using silicon carbide refractory castables in monolithic refractory materials, the advantages, disadvantages, and prices of use should be considered. Only after the use site is determined can the lining material be used more accurately. However, in the actual use environment of monolithic refractory castables, these favorable and unfavorable environments for silicon carbide are mostly mixed. The evaluation of many environments currently used is often inconsistent with the actual use environment.

Lightweight High-Strength Thermal Insulation Castable

Lightweight high-strength castable is a new type of refractory material newly developed by Rongsheng Refractory Material Manufacturer. Rongsheng Lightweight High-Strength Thermal Insulation Castable combines the advantages of lightweight materials and high-strength characteristics and is widely used in high-temperature industrial equipment. This material not only has good thermal insulation performance but also is comparable to heavy refractory bricks in strength. Contact Rongsheng for more information.

Lightweight High-Strength Insulation Castable

Basic Characteristics of Lightweight High-Strength Castables

Lightweight high-strength castables are composed of refractory aggregates (such as lightweight particles), binders, and additives (such as reinforcing materials). Its main characteristics include:

• Lightweight: The castable contains lightweight aggregates (such as lightweight bauxite, expanded perlite, lightweight silicates, etc.), which makes the overall weight of the material lighter and has a lower density.
• High strength: Although it is a lightweight material, after special formula design and process treatment, it can achieve strength similar to that of traditional heavy refractory bricks, and can withstand large mechanical loads and structural stresses at high temperatures.
• Thermal insulation: Due to the special structure of its lightweight aggregate, lightweight high-strength castables have excellent thermal insulation properties, which help to reduce heat loss and improve energy efficiency.
• High refractoriness: This type of castable is usually composed of refractory aggregates and binders, has high refractoriness, and can work stably in high-temperature environments.
• Thermal shock resistance: Due to its certain elasticity and toughness, lightweight and high-strength castables have good thermal shock resistance and can cope with working environments with large temperature changes.

Advantages of Lightweight High-Strength Castables

(1) Thermal insulation performance

Reduced heat loss: The lightweight aggregate of lightweight high-strength castables makes it have lower thermal conductivity, which can effectively reduce the conduction and loss of heat. This is of great significance for equipment that needs to maintain high temperatures for a long time (such as blast furnaces, hot blast furnaces, smelting furnaces, etc.), and can reduce energy consumption.

Lightweight High-Strength Castables

Improved temperature control: Good thermal insulation effect makes the temperature distribution in the equipment more uniform, avoids excessive temperature fluctuations, and reduces the occurrence of thermal shock.

(2) High strength

Withstand greater mechanical stress: The high-strength design enables lightweight high-strength castables to withstand greater mechanical stress and impact, especially in some areas affected by high temperature and pressure (such as the inner wall of the furnace, the bottom of the furnace, etc.), and can maintain stability.

Comparable to heavy refractory bricks: Traditional heavy refractory bricks have higher strength, but are often heavier and are not suitable for occasions where a lower dead weight is required. The strength of lightweight high-strength castables has been optimized to be comparable to that of heavy refractory bricks, while having a lower density.

(3) Convenient construction

Quick forming: Castables are constructed by pouring, vibrating or spraying, which is particularly suitable for irregular shapes and difficult-to-brick parts. This construction method not only saves time and manpower, but also avoids the existence of bricklaying joints during the construction process, improving the construction quality.

Adaptable to complex structures: Since the material is in a cast state, it is suitable for use in furnace bodies, furnace walls, furnace bottoms and other parts with complex shapes or difficult to cut and splice.

(4) Good thermal shock resistance

Lightweight and high-strength castables can better adapt to working environments with large temperature fluctuations due to the structural characteristics of their lightweight aggregates, avoiding thermal stress and cracks caused by drastic temperature changes. This enables it to effectively improve durability and stability in equipment such as hot blast furnaces and blast furnaces.

(5) Energy saving and maintenance reduction

Due to its excellent thermal insulation performance, lightweight high-strength castables help improve the energy efficiency of the equipment. It reduces energy waste and enables equipment to operate at a higher thermal efficiency, reducing operating costs.

Its good thermal shock resistance, high-temperature resistance, and strength also extend the service life of the refractory lining, thereby reducing the frequency of maintenance and replacement and reducing overall operating costs.

Rongsheng Refractory Castable Manufacturer

Rongsheng's lightweight high-strength castable is a refractory material that combines light weight, high strength, excellent thermal insulation and thermal shock resistance. It can provide good performance in high-temperature metallurgical equipment. Compared with traditional refractory bricks, it can provide similar or even stronger strength. And due to its lightweight structure, it has better thermal isolation effect, helping to improve the energy efficiency of equipment and reduce repair and maintenance costs. It is especially suitable for metallurgical equipment that requires high strength, good thermal insulation and high temperature resistance and thermal shock resistance. Such as blast furnaces, hot blast furnaces, coke ovens, steelmaking furnaces, etc.

Quality Requirements for Checker Bricks in Coke Oven Regenerators

The quality requirements of the checker bricks in the heat storage chamber are mainly as follows:

1. In order to reduce the friction resistance of the gas flowing in the checker bricks and make the resistance in each heat storage chamber consistent, it is convenient to master the heating system, and the holes of the upper and lower layers of the checker bricks are required to be aligned as much as possible.

2. Keep the checker bricks clean to avoid blockage of the brick holes and reduce the number of cleaning times during production to improve heating efficiency.

3. The bricklayer should be laid smoothly and have a good staggered width.

4. Maintain necessary expansion joints. The gas flow space at the top of the heat storage chamber should maintain a certain cross-sectional area according to the design to prevent vortexes from being generated when the gas is distributed at the top of the heat storage chamber.

Rongsheng Checker Bricks

Rongsheng Refractory Manufacturer, Regenerator Checker Brick, Magnesia Checker Brick. Contact Rongsheng for more information.

Construction of checker bricks

The laying time of checker bricks is divided into two construction methods according to the width of the regenerator: laying at the same time as the regenerator furnace wall (first laying) and laying after the entire furnace body is built and cleaned (latter laying). According to construction experience, when the net width of the regenerator is less than 310 mm (such as Otto coke oven), the construction method of laying checker bricks first should generally be adopted. This is because it is more difficult to lay checker bricks later in a narrow regenerator.

The construction method of laying checker bricks first has several advantages: First, because the workers are standing on the wall of the regenerator to lay checker bricks, the operating conditions are better, and it is easy to check after laying. Therefore, it can ensure that each checker brick hole is connected from top to bottom and has good staggered joints. However, due to the addition of many processes - cleaning protection and cleaning work, the construction progress is slow and it is more difficult to ensure cleaning.

The construction method of laying checker bricks is as follows: checker bricks can be laid in sections, that is, according to the convenience of construction, they can be laid in two sections on the entire height of the heat storage chamber, that is, divided into upper and lower sections according to the height of the replacement handrail. After the first section of the main wall is built, all the cleaning and brick joint finishing work on the wall surface is completed, and the grate bricks are cleaned, and the row numbers of the grate bricks are checked once, and then the first layer of checker bricks is placed on the grate foot platform according to the designed position, and the expansion joints on the four sides and the staggered joint width between the checker bricks and the grate foot platform are checked. Make sure that the checker bricks can be firmly placed on the grate foot platform, and finally lay each layer of checker bricks from the center partition wall to both sides according to the designed position.

During construction, the checker bricks are placed on the brick pad. The hook of the checker brick is inserted into the hole of the checker brick to place the checker brick in the heat storage chamber. Then use a long wooden stick to adjust its position. When storing, it can be laid from the center to the furnace head in a stepped shape, or it can be laid layer by layer. The heat storage chamber sealing wall is built after the checker bricks of this section are laid.

After the first section of checker bricks is laid, the checker bricks are covered with a checker brick protection board to prevent waste such as mortar from falling into the checker bricks. Then continue to build the heat storage chamber wall. When it reaches the top of the heat storage chamber, lay the second section of checker bricks and build the second section of sealing wall.