Furnace surface precast block with double-layer material structure and preparation method of furnace surface precast block

Abstract

The invention provides a furnace surface prefabricated block with a double-layer material structure and a preparation method of the furnace surface prefabricated block, and belongs to the field of flame path walls of prebaked anode roasting furnaces for aluminum. The furnace surface precast block comprises a lower heavy castable layer and a lower heavy castable layer, the upper light castable layer is provided with embedded round steel reinforcing ribs; the transition layer is arranged between the heavy castable layer and the light castable layer, and the transition layer is formed by embedding a concave-convex structure on the surface layer of the heavy castable layer; and the combustion observation hole penetrates through the heavy castable layer and the light castable layer. The lower heavy castable layer is made of a high-density material, so that mechanical strength, wear resistance and slag permeability resistance are provided; the upper light castable layer is made of a low-density material, so that the heat conductivity coefficient is reduced, and the energy-saving target is achieved; and the transition layer can enhance the binding force of the double-layer material through mechanical occlusion and reduce the interlayer stripping risk caused by thermal expansion difference, so that the heat dissipation of the outer surface can be reduced and the heat loss can be reduced while the high-temperature-resistant requirement of the lower part of the furnace surface precast block is met.

Description

Technical Field

[0001] The present application relates to the technical field of the flue wall of the pre-baked anode baking furnace for aluminum, and particularly relates to a furnace surface precast block with a double-layer material structure and a preparation method thereof. Background Art

[0002] At present, the upper layer of the flue wall of the open-type circular baking furnace for pre-baked anodes for aluminum is usually a furnace surface precast block made of refractory castable, with round holes reserved as gas injection inlets and observation ports. The furnace surface precast block serves as the top cover plate of the flue to seal the top of the flue, and is also the production operation passage and equipment placement area. The lower part of the top refractory brick is close to the high-temperature area, which needs to withstand high temperature and thermal shock, and needs to have good thermal stability. Its upper part is exposed in the workshop, and it is required to maintain a relatively low temperature to reduce heat loss and ensure production operation and equipment operation.

[0003] To meet the requirement of high temperature resistance, the furnace surface block is usually made of heavy castable. Although it can meet the requirement of high temperature resistance, it causes a high surface temperature, large heat dissipation, energy loss, and affects production operation and equipment operation. Summary of the Invention

[0004] The present application provides a furnace surface precast block with a double-layer material structure and a preparation method thereof to solve the following technical problems: how to meet the requirement of high temperature resistance of the lower part of the furnace surface precast block while reducing the heat dissipation of the outer surface and reducing heat loss.

[0005] In a first aspect, an embodiment of the present application provides a furnace surface precast block with a double-layer material structure, and the furnace surface precast block includes:

[0006] A lower heavy castable layer, and the volume density of the castable of the lower heavy castable layer is 2.0 g / cm 3 ~2.4 g / cm 3 ;

[0007] An upper lightweight castable layer, and the upper lightweight castable layer is provided with embedded round steel reinforcement bars, and the volume density of the castable of the upper lightweight castable layer is 1.4 g / cm 3 ~1.6 g / cm 3 ;

[0008] A transition layer, which is arranged between the heavy castable layer and the lightweight castable layer, and the transition layer is formed by embedding concave-convex structures on the surface layer of the heavy castable layer;

[0009] A combustion observation hole, which penetrates through the heavy castable layer and the lightweight castable layer.

[0010] Optionally, the furnace surface precast block further includes:

[0011] A reserved hoisting opening is provided at the edge of the upper lightweight castable layer.

[0012] Optionally, the furnace top precast block further includes:

[0013] A circular male buckle is provided at the bottom of the heavy castable layer for mating with the female mouth of the flue brick.

[0014] Optionally, the furnace top precast block further includes:

[0015] A heat insulation opening is provided at the edge of the lightweight castable layer for mating with the refractory fiber blanket on the upper layer of the flue.

[0016] Optionally, the furnace top precast block further includes:

[0017] A fixing frame is disposed around the furnace top precast block, and the material of the fixing frame is angle steel.

[0018] Optionally, the concave-convex shape includes one or more of a boss, a cone, or a blade shape.

[0019] Optionally, the upper part of the combustion observation hole is a bowl-shaped structure, and the lower part is an upper conical structure.

[0020] Optionally, by mass, the castable of the lower heavy castable layer includes the following chemical components: 70 to 80 parts of main aggregate, 10 to 15 parts of silicon carbide micropowder, 8 to 12 parts of calcium aluminate cement, 2 to 3 parts of zirconia fiber, and 0.15 to 0.25 parts of polycarboxylate-based water reducer; wherein,

[0021] The main aggregate is composed of brown fused alumina and white fused alumina, and the mass ratio of the brown fused alumina to the white fused alumina is (1 to 3):1;

[0022] The fiber length of the zirconia fiber is 3 mm to 5 mm.

[0023] Optionally, by mass, the castable of the upper lightweight castable layer includes the following chemical components: 55 to 70 parts of porous mullite aggregate, 15 to 25 parts of hollow alumina microspheres, 7 to 9 parts of aluminate cement, 4 to 6 parts of silica sol, 1.5 to 2.5 parts of aluminum silicate fiber, and 0.03 to 0.07 parts of aluminum powder foaming agent; wherein,

[0024] The pore diameter of the porous mullite aggregate is 0.5 to 2 mm.

[0025] In a second aspect, the present application provides a preparation method for the furnace top precast block according to any one of the embodiments in the first aspect, and the method includes:

[0026] According to the dimensions of the furnace surface precast block, the overall mold, the bottom mold, the combustion observation hole mold and the transition template are respectively designed.

[0027] Lay the bottom mold under the overall mold, place the lower mold of the combustion observation hole, then add heavy casting material and vibrate it preliminarily to form the lower heavy casting material layer.

[0028] Embed the transition template into the surface layer of the heavy casting material, and then remove the transition template to form the transition layer.

[0029] Place the upper mold of the combustion observation hole above the lower mold of the combustion observation hole, then add light casting material and embed round steel reinforcement bars to form the upper light casting material layer, obtaining the semi-finished precast block.

[0030] Cure the semi-finished precast block, and then remove the mold to obtain the furnace surface precast block.

[0031] The above technical solution provided by the embodiment of the present application has the following advantages compared with the prior art:

[0032] The embodiment of the present application provides a furnace surface precast block with a double-layer material structure. The furnace surface precast block adopts a double-layer material structure, with a lower heavy casting material layer, an upper light casting material layer, and a transition layer in the middle. The lower heavy casting material layer uses a high-density material to provide mechanical strength, wear resistance and slag penetration resistance; the upper light casting material layer uses a low-density material to reduce the thermal conductivity coefficient and achieve the energy-saving goal; the transition layer is formed by embedding the concave-convex structure on the surface layer of the heavy casting material layer, which can enhance the bonding force of the double-layer material through mechanical occlusion, reduce the risk of interlayer peeling caused by thermal expansion differences, and disperse thermal stress at the same time, improving the thermal shock resistance. Thus, while meeting the high-temperature resistance requirements of the lower part of the furnace surface precast block, it can also reduce the heat dissipation on the outer surface and reduce heat loss. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The accompanying drawings here are incorporated into the specification and form a part of this specification, showing the embodiments consistent with the present application, and are used together with the specification to explain the principles of the present application.

[0034] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the accompanying drawings required for the description of the embodiments or the prior art. Obviously, for those of ordinary skill in the art, other accompanying drawings can be obtained based on these drawings without creative efforts.

[0035] Figure 1 It is a schematic structural diagram of the furnace surface precast block provided by the embodiment of the present application;

[0036] Figure 2The sectional view taken along the line B-B provided by the embodiment of the present application Figure 1 ;

[0037] Figure 3 The layout structure diagram of the fixed frame and the round steel reinforcement provided by the embodiment of the present application Figure 1 ;

[0038] Figure 4 The process schematic diagram of a preparation method of a furnace surface precast block provided by the embodiment of the present application

[0039] Reference numerals:

[0040] 1 - lower heavy castable layer, 2 - upper light castable layer, 3 - fixed frame in the length direction, 4 - fixed frame in the width direction, 5 - round steel reinforcement, 6 - reserved lifting opening, 7 - circular male buckle, 8 - heat insulation opening, 9 - combustion observation hole, 10 - upper conical joint Detailed implementation manners

[0041] To make the objectives, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are some but not all of the embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present application without creative efforts shall fall within the protection scope of the present application

[0042] The various embodiments of the present application may exist in the form of a range; it should be understood that the description in the form of a range is only for convenience and brevity, and should not be construed as a rigid limitation on the scope of the present application; therefore, it should be considered that the described range description has specifically disclosed all possible sub-ranges and single values within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and single numbers within the range, such as 1, 2, 3, 4, 5, and 6, regardless of the range. Additionally, whenever a numerical range is indicated herein, it means including any cited number (fraction or integer) within the indicated range

[0043] In addition, in the description of the specification of the present application, terms such as "include" and "comprise" mean "including but not limited to". In this text, relative terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. When a layer / component is referred to as being "on" another layer / component, the layer / component can be directly on the other layer / component, or there can be an intermediate layer / component between them. Additionally, if a layer / component is "on" another layer / component in one orientation, then when the orientation is reversed, the layer / component can be "under" the other layer / component. In the context of the present disclosure, similar or identical components may be denoted by the same or similar reference numerals.

[0044] In addition, it should be noted that in the description of the present application, unless otherwise clearly specified and limited, the terms "mounted", "connected", and "coupled" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection, it can be a mechanical connection, an electrical connection, a direct connection, or an indirect connection through an intermediate medium, and it can be the communication inside two components. For those skilled in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances.

[0045] Unless otherwise specifically stated, various raw materials, reagents, instruments, and equipment used in the present application can be obtained through market purchase or can be prepared by existing methods.

[0046] Figure 1 Structural schematic diagram of the stove top precast block provided for the embodiments of the present application;

[0047] Figure 2 Provided for the embodiments of the present application Figure 1 B - B cross-sectional view;

[0048] Figure 3 Provided for the embodiments of the present application Figure 1 Arrangement structure diagram of the fixed frame and round steel reinforcement;

[0049] As Figures 1 to 3 shown, the present application provides a stove top precast block with a double-layer material structure, and the stove top precast block includes:

[0050] Lower heavy castable layer, and the volume density of the castable of the lower heavy castable layer is 2.0 g / cm 3 ~2.4 g / cm 3 ;

[0051] Upper light castable layer, with round steel reinforcement bars embedded in the upper light castable layer, and the volume density of the castable of the upper light castable layer is 1.4 g / cm 3 ~1.6 g / cm 3 ;

[0052] Transition layer, arranged between the heavy castable layer and the light castable layer, and the transition layer is formed by embedding concave-convex structures on the surface layer of the heavy castable layer;

[0053] Combustion observation hole, penetrating through the heavy castable layer and the light castable layer.

[0054] In some embodiments, the furnace top precast block further includes:

[0055] Reserved lifting opening, opened at the edge of the upper light castable layer.

[0056] In some embodiments, the furnace top precast block further includes:

[0057] Round male buckle, opened at the bottom of the heavy castable layer, for cooperating with the female mouth of the flue brick.

[0058] In some embodiments, the furnace top precast block further includes:

[0059] Heat insulation opening, opened at the edge of the light castable layer, for cooperating with the refractory fiber blanket on the upper layer of the flue.

[0060] In some embodiments, the furnace top precast block further includes:

[0061] Fixed frame, surrounding the furnace top precast block, and the material of the fixed frame is angle steel.

[0062] In some embodiments, the concave-convex shape includes one or more of a convex platform, a cone or a blade shape.

[0063] In some embodiments, the upper part of the combustion observation hole is a bowl-shaped structure, and the lower part is an upper conical structure.

[0064] In the embodiments of the present application, the structure of the furnace top precast block is reasonably designed, which is beneficial to the heat preservation of the flue temperature, reduces heat loss, improves heat utilization rate, reduces the consumption of fuel natural gas, etc., saves production costs, and is also beneficial to the perfect fit with the flue furnace top brick to improve stability, durability, reduce deformation, and improve the service life of the flue. Specifically, the functions of the structures of each component are as follows:

[0065] The volume density of the castable of the lower heavy castable layer is 2.0 - 2.4 g / cm 3, high-density materials can provide mechanical strength, wear resistance, and slag penetration resistance, and are suitable for direct contact with high-temperature areas, thus ensuring structural stability. Exemplarily, the bulk density of the castable in the lower heavy castable layer is 2.0 g / cm 3 , 2.1 g / cm 3 , 2.2 g / cm 3 , 2.3 g / cm 3 , 2.4 g / cm 3 and so on.

[0066] The bulk density of the castable in the upper light castable layer is 1.4 - 1.6 g / cm 3 , and low-density materials can reduce the thermal conductivity, reduce heat loss, and achieve energy-saving goals. Exemplarily, the bulk density of the castable in the upper light castable layer can be 1.4 g / cm 3 , 1.45 g / cm 3 , 1.5 g / cm 3 , 1.55 g / cm 3 , 1.6 g / cm 3 and so on.

[0067] The transition layer (concave-convex structure) can enhance the bonding force of the double-layer material through mechanical interlocking and reduce the risk of interlayer peeling caused by thermal expansion differences; the concave-convex structure (such as bosses, cones) disperses thermal stress and improves thermal shock resistance.

[0068] The combustion observation hole (bowl-shaped upper part + conical lower part) penetrates the double-layer structure to facilitate real-time monitoring of the combustion state in the furnace. The bowl-shaped design expands the observation range, and the conical structure disperses the stress at the orifice to prevent edge cracking.

[0069] The reserved lifting hole (at the edge of the light layer) can facilitate the lifting construction of the precast block, and the edge setting reduces the impact on the insulation performance.

[0070] The circular male buckle (at the bottom of the heavy layer) can be accurately matched with the female mouth of the flue brick to ensure accurate positioning of the precast block and improve the overall structural stability.

[0071] The heat insulation port (at the edge of the light layer) can cooperate with the refractory fiber blanket to form a continuous sealing layer to further reduce heat loss at the joints.

[0072] The angle steel fixing frame can surround the precast block on all sides, enhance the overall anti-deformation ability, and prevent the edge from being damaged due to thermal stress or mechanical impact.

[0073] In some embodiments, by mass, the castable in the lower heavy castable layer comprises the following chemical components: 70 - 80 parts of main aggregate, 10 - 15 parts of silicon carbide micropowder, 8 - 12 parts of calcium aluminate cement, 2 - 3 parts of zirconia fiber, 0.15 - 0.25 parts of polycarboxylate-based water reducer; wherein,

[0074] The main aggregate is composed of brown corundum and white corundum, and the mass ratio of the brown corundum to the white corundum is (1-3):1;

[0075] The fiber length of the zirconium oxide fiber is 3 mm to 5 mm.

[0076] It should be noted that the functions of the components of the lower heavy castable layer are as follows:

[0077] Brown corundum has an aluminum oxide (Al2O3) content of about 95% to 97%, and contains a small amount of impurities such as Fe, Si, and Ti. It is made from bauxite, coke (or anthracite), and iron filings, and is smelted at high temperature in an electric arc furnace.

[0078] The purity of alumina of white corundum is ≥99%, with very few impurities (such as SiO2, Fe2O3 <0.1%). It is made of industrial alumina powder as the main raw material through high-temperature electric melting process.

[0079] Main aggregate (brown corundum + white corundum, mass ratio 1-3:1, 70-80 parts): Brown corundum has high hardness (Mohs hardness 9.1) and good thermal shock resistance, and is suitable for bearing high-temperature mechanical stress. The purity of white corundum is ≥99% (Al2O3 content), and it has strong corrosion resistance and can resist slag penetration. The toughness of brown corundum makes up for the brittleness of white corundum, and the ratio of the two is adjusted (1-3:1) to balance high-temperature strength and corrosion resistance, and adapt to the harsh environment where the furnace surface is in direct contact with the flame. Exemplarily, the weight of the main aggregate can be 70 parts, 72 parts, 74 parts, 76 parts, 78 parts, 80 parts, etc., and the mass ratio of brown corundum to the white corundum is 1:1, 1.5:1, 2:1, 2.5:1, 3:1, etc.

[0080] Silicon carbide powder (SiC) is a high-performance ceramic material formed by high-temperature synthesis (about 2000°C) of silicon (Si) and carbon (C).

[0081] Silicon carbide powder (10-15 parts): Silicon carbide powder can improve thermal conductivity and thermal shock resistance, and form a SiC oxide layer at high temperature to enhance corrosion resistance. Silicon carbide powder can form a dense network with corundum aggregate, reduce porosity, and improve overall wear resistance. Exemplarily, the weight of the silicon carbide powder can be 10 parts, 11 parts, 12 parts, 13 parts, 14 parts, 15 parts, etc.

[0082] Pure calcium aluminate cement is a hydraulic binder made from high-purity calcium oxide (CaO) and aluminum oxide (Al2O3) by high-temperature sintering or electric melting. Its aluminum oxide content is usually 70% to 80%.

[0083] Calcium aluminate cement (8 - 12 parts): Calcium aluminate cement can serve as a binder to provide early strength, generating mineral phases such as CA2 and CA6 at high temperatures to maintain structural stability. Calcium aluminate cement can react with silicon carbide micropowder to form aluminosilicate, enhancing the medium-temperature strength. Exemplarily, the weight parts of the calcium aluminate cement can be 8 parts, 9 parts, 10 parts, 11 parts, 12 parts, etc.

[0084] Zirconia fiber is a high-performance ceramic fiber with zirconia as the main component.

[0085] Zirconia fiber (2 - 3 parts, fiber length 3mm - 5mm): It inhibits crack propagation through the fiber bridging effect, enhancing thermal shock resistance. At the same time, long fibers (5mm) enhance the three-dimensional toughening effect and form an interlocking structure with corundum aggregate. Exemplarily, the weight parts of the zirconia fiber can be 2 parts, 2.2 parts, 2.4 parts, 2.6 parts, 2.8 parts, 3 parts, etc.

[0086] Polycarboxylate superplasticizer (abbreviated as PCE) is a high-performance concrete admixture. Through molecular design, it forms a comb-like or dendritic structure, with a main chain carrying charged groups such as sulfonic acid groups, and the side chains achieving long-term dispersion through steric hindrance effects.

[0087] Polycarboxylate superplasticizer (0.15 - 0.25 parts): Polycarboxylate superplasticizer can reduce the water-cement ratio (water demand ≤ 6%), improve fluidity and density, and reduce construction defects. Polycarboxylate superplasticizer can optimize the cement dispersion and promote the uniform distribution of zirconia fiber. Exemplarily, the weight parts of the polycarboxylate superplasticizer can be 0.15 parts, 0.17 parts, 0.20 parts, 0.22 parts, 0.25 parts, etc.

[0088] In some embodiments, by mass parts, the castable of the upper lightweight castable layer includes the following chemical components: porous mullite aggregate 55 - 70 parts, hollow alumina microspheres 15 - 25 parts, aluminate cement 7 - 9 parts, silica sol 4 - 6 parts, aluminosilicate fiber 1.5 - 2.5 parts, aluminum powder foaming agent 0.03 - 0.07 parts; wherein,

[0089] The pore diameter of the porous mullite aggregate is 0.5 - 2mm.

[0090] It should be noted that the functions of the components of the upper lightweight castable layer are as follows:

[0091] Porous mullite aggregate is an artificial synthetic lightweight refractory material with mullite (chemical formula 3Al2O3·2SiO2) as the main crystal phase, forming an aggregate with a microporous structure through high-temperature sintering or electrofusion process.

[0092] Porous mullite aggregate (55 - 70 parts, pore size 0.5 - 2 mm): The porous structure can reduce the thermal conductivity and provide a framework support at the same time. Controlling the pore size within 0.5 - 2 mm can balance the heat insulation performance and mechanical strength. Exemplarily, the mass parts of the porous mullite aggregate can be 55 parts, 60 parts, 65 parts, 68 parts, 70 parts, etc.

[0093] Hollow alumina microspheres are lightweight ceramic particles with a high-purity alumina (Al2O3 ≥ 99%) shell and a hollow structure inside.

[0094] Hollow alumina microspheres (15 - 25 parts): Closed pores further reduce the thermal conductivity and lighten the density. At the same time, they can fill the gaps between porous mullite to form a double heat insulation barrier. Exemplarily, the mass parts of the hollow alumina microspheres can be 15 parts, 17 parts, 20 parts, 22 parts, 25 parts, etc.

[0095] Aluminate Cement is a hydraulic cementitious material mainly composed of calcium aluminate, which is made by grinding the raw materials of bauxite and limestone after high-temperature calcination (1300 - 1500 °C), and the alumina (Al2O3) content is usually 50% - 70%.

[0096] Aluminate Cement (7 - 9 parts): It can provide bonding strength and enhance the structural stability by generating CA phase at high temperatures. It can cooperate with silica sol to improve the medium-temperature bonding strength. Exemplarily, the mass parts of the aluminate cement can be 7 parts, 7.5 parts, 8 parts, 8.5 parts, 9 parts, etc.

[0097] Silica sol is a colloidal solution formed by the uniform dispersion of nanoscale silicon dioxide (SiO2) particles in water or organic solvents, and its chemical formula can be expressed as SiO2·nH2O.

[0098] Silica sol (4 - 6 parts): Nanoscale SiO2 particles fill the micropores, improving the density and high-temperature adhesiveness. It forms a gel network with aluminate cement to reduce high-temperature shrinkage cracks. Exemplarily, the mass parts of the silica sol can be 4 parts, 4.5 parts, 5 parts, 5.5 parts, 6 parts, etc.

[0099] Aluminosilicate Fiber is an inorganic fiber material mainly composed of SiO2 (48% - 52%) and Al2O3 (43% - 49%), supplemented with a small amount of Fe2O3, CaO, and MgO.

[0100] Aluminum silicate fiber (1.5 - 2.5 parts): The fibers are intertwined to enhance crack resistance and adapt to temperature fluctuations. It optimizes the pore distribution together with hollow microspheres to prevent stress concentration. Exemplarily, the mass parts of the aluminum silicate fiber can be 1.5 parts, 1.7 parts, 2 parts, 2.2 parts, 2.5 parts, etc.

[0101] The aluminum powder foaming agent is a functional additive that forms closed pores inside the material by releasing gases (such as hydrogen) through the chemical reaction of aluminum (Al) at high temperatures or in alkaline environments.

[0102] Aluminum powder foaming agent (0.03 - 0.07 parts): It foams to generate micropores and reduces the bulk density. It forms a gradient pore structure in combination with porous mullite to improve the heat insulation efficiency. Exemplarily, the mass parts of the aluminum powder foaming agent can be 0.03 parts, 0.04 parts, 0.05 parts, 0.06 parts, 0.07 parts, etc.

[0103] In the embodiments of the present application, the corundum skeleton provides mechanical strength, silicon carbide fills the gaps to improve the thermal conductivity uniformity and reduce the thermal stress gradient. The polycarboxylate water reducer optimizes the fiber dispersion, and the fibers enhance the thermal shock resistance. The two work together to extend the service life of the material. The porous aggregate of porous mullite provides macroscopic pores, and hollow alumina microspheres fill the microscopic pores to form a double thermal insulation barrier. The nano - SiO₂ of silica sol enhances the high - temperature stability of the hydration products of aluminate cement and reduces the mid - temperature strength attenuation. In addition, the high density support of the heavy layer and the low thermal conductivity of the light layer are complementary, and mechanical interlocking and thermal expansion coordination are achieved through the concave - convex structure (such as bosses) of the transition layer. The double - layer composite design enables the furnace surface precast block to have both erosion - resistance (heavy layer) and heat insulation and energy - saving (light layer) functions, and the comprehensive thermal efficiency is increased by 20% - 30%.

[0104] Figure 4 It is a schematic flow chart of a preparation method of a furnace surface precast block provided by the embodiments of the present application.

[0105] As Figure 4 shown, the present application provides a preparation method of the furnace surface precast block described in any one of the above - mentioned embodiments, and the method includes:

[0106] S1. According to the size of the furnace surface precast block, respectively design and obtain the overall mold, bottom mold, combustion observation hole mold, and transition template;

[0107] S2. Lay the bottom mold under the overall mold, place the lower mold of the combustion observation hole, then add the heavy casting material and vibrate it preliminarily to form the lower heavy casting material layer;

[0108] S3. Embed the transition template into the surface layer of the heavy casting material, and then remove the transition template to form the transition layer;

[0109] S4. Above the lower die of the combustion observation hole, place the upper die corresponding to the combustion observation hole, then add lightweight castable, and embed round steel reinforcing bars to form the upper lightweight castable layer, obtaining a semi-finished precast block;

[0110] S5. Cure the semi-finished precast block, and then remove the die to obtain the furnace surface precast block.

[0111] In summary, a furnace surface precast block with a double-layer material structure and its preparation method provided by the embodiments of the present application have the following advantages:

[0112] (1) Rationality of structural design: The furnace surface precast block adopts a double-layer material structure, with a heavyweight castable layer at the lower layer, a lightweight castable layer at the upper layer, and a transition layer in the middle. This design is beneficial for heat preservation of the flue temperature, reducing heat loss, improving heat utilization rate, reducing fuel consumption, and is also beneficial for perfect fitting with the flue furnace top brick, improving the stability and durability of the overall structure, reducing deformation, and extending the service life of the flue.

[0113] (2) Scientificity of material selection: The lower heavyweight castable layer uses high-density materials to provide mechanical strength, wear resistance, and slag penetration resistance; the upper lightweight castable layer uses low-density materials to reduce the thermal conductivity coefficient and achieve the energy-saving goal. At the same time, the chemical components in the two castable layers are carefully proportioned to enable them to exert their best performance, such as the corundum skeleton providing mechanical strength, silicon carbide filling the gaps to improve thermal conductivity uniformity, and polycarboxylate water reducer optimizing fiber dispersion, etc.

[0114] (3) Innovation of the transition layer: The transition layer is formed by embedding concave-convex structures on the surface layer of the heavyweight castable layer. This design can enhance the bonding force between the double-layer materials through mechanical interlocking, reduce the risk of interlayer peeling caused by thermal expansion differences, and at the same time disperse thermal stress and improve thermal shock resistance.

[0115] (4) Diversity of functionality: The furnace surface precast block is also designed with functional structures such as a combustion observation hole, a reserved lifting port, a circular female buckle, a heat insulation port, and a fixing frame. The combustion observation hole is convenient for real-time monitoring of the combustion state in the furnace; the reserved lifting port is convenient for the lifting construction of the precast block; the circular female buckle ensures accurate positioning of the precast block; the heat insulation port and the refractory fiber blanket cooperate to form a continuous sealing layer to further reduce heat loss at the joint; the fixing frame enhances the overall anti-deformation ability.

[0116] (5) Simplicity of the preparation method: The preparation method of the furnace surface precast block includes steps such as designing the die, laying the bottom die, adding castable, forming the transition layer, adding lightweight castable and embedding reinforcing bars, curing, and removing the die. This method is simple to operate and easy to realize industrial production.

[0117] (6) Improvement in comprehensive thermal efficiency: Through the double-layer composite design and carefully proportioned chemical components, the furnace surface precast block has both erosion resistance and heat insulation and energy-saving functions. The comprehensive thermal efficiency is increased by 20% - 30%, effectively reducing production costs and energy consumption.

[0118] The preparation product of the preparation method of the furnace surface precast block is the above-mentioned furnace surface precast block. The composition and structure of the furnace surface precast block prepared by the preparation method of the furnace surface precast block can refer to the above embodiments. Since the preparation method of the furnace surface precast block adopts some or all of the technical solutions of the furnace surface precast block embodiment, it at least has all the beneficial effects brought by the technical solutions of the furnace surface precast block embodiment, and will not be elaborated one by one here.

[0119] The following further elaborates on this application in combination with specific embodiments. It should be understood that these embodiments are only used to illustrate this application and not to limit the scope of this application. The experimental methods without specific conditions noted in the following embodiments are usually determined according to industry standards. If there is no corresponding industry standard, they are carried out according to general international standards, conventional conditions, or conditions recommended by the manufacturer.

[0120] Example 1

[0121] Manufacture the mold: The mold size is 1300 mm in length, 530 mm in width, the diameter of the circular female buckle reserved opening is 20 mm, the height of the heat insulation layer reserved opening is 20 mm, the width is 310 mm, the length is 1300 mm, the diameter of the lifting reserved opening is 25 mm, the depth is 40 mm, and the diameters of the sealing and gas ports from top to bottom are 360 mm, 210 mm, and 310 mm respectively. And evenly spray the mold release agent. First, mix 75.25 parts of brown fused alumina + white fused alumina (the mass ratio of brown fused alumina to white fused alumina is 2:1) as the main aggregate, 9 parts of auxiliary aggregate silicon carbide micropowder, 12 parts of calcium aluminate cement, 3.5 parts of zirconia fiber with a fiber length of 3 mm, and 0.25 part of polycarboxylate-based water reducer as the binder and additive and stir evenly, and control the bulk density to be 2.4 g / cm 3 of the heavy castable, and evenly add it to the mold. During the pouring of the heavy castable, use a vibrating rod to vibrate 3 times. Stop pouring when the pouring height reaches 200 mm. After standing for 1 hour, before it solidifies, press a transition template with multiple convex-shaped protrusions (the upper opening of the convex is 30 mm, the lower opening is 20 mm, and the height is 80 mm) into the heavy castable, and vibrate it with a vibrator on it. After shaping for 24 hours, remove the transition template; then mix 64 parts of porous mullite aggregate as the main aggregate, 18.44 parts of auxiliary aggregate hollow alumina microspheres, 9 parts of aluminate cement, 6 parts of silica sol, 2.5 parts of aluminum silicate fiber, and 0.06 part of aluminum powder foaming agent as the binder and additive and stir evenly, and control the bulk density to be 1.6 g / cm 3The lightweight insulating material is added to the upper part of the medium-heavy castable. During the pouring of the lightweight insulating material, a vibrating rod is used to vibrate it repeatedly 2 times. When the pouring reaches 330 mm, the pouring is stopped. After horizontally placing 4 round steel bars with a diameter of 12 mm and a length of 510 mm into the castable, the pouring is continued until it reaches 400 mm to complete the pouring. Then, round wooden bars with a diameter of 25 mm and a length of 45 mm are inserted, two at each end, at a position 120 mm from the upper part and 350 mm from the center. After standing and setting for 48 hours, the mold is removed, and angle steels with a width of 80 mm and lengths of 1300 mm and 530 mm are fixed to the upper part of the precast block. After continuing to stand and set for 72 hours, it is completed and ready for use.

[0122] Example 2

[0123] Manufacture the mold: The mold dimensions are 1300 mm in length, 550 mm in width, the diameter of the reserved opening of the round female buckle is 25 mm, the height of the reserved opening of the heat insulation layer is 25 mm, the width is 330 mm, the length is 1300 mm, the diameter of the reserved lifting opening is 30 mm, the depth is 50 mm, and the diameters of the sealing and gas ports from top to bottom are 380 mm, 220 mm, and 330 mm respectively. And a certain amount of mold release agent is evenly sprayed. In sequence, 78 parts of brown fused alumina + white fused alumina (the mass ratio of brown fused alumina to the white fused alumina is 1:1) as the main aggregate, 8 parts of auxiliary aggregate silicon carbide micropowder, 11 parts of calcium aluminate cement, 2.8 parts of zirconia fiber with a fiber length of 4 mm, and 0.2 part of polycarboxylate-based water reducer as the binder and additive are mixed and stirred evenly, and the bulk density is controlled at 2.2 g / cm 3 of the heavy castable is evenly added to the mold. During the pouring of the heavy castable, a vibrating rod is used to vibrate it 2 times. When the pouring height reaches 250 mm, the pouring is stopped. After standing for 1.5 hours, before it solidifies, a conical mold with a transition template having multiple conical protrusions (the upper mouth of the cone is 40 mm, the lower mouth is 30 mm, and the height is 60 mm) is pressed into the heavy castable, and it is vibrated with a vibrator on it. After setting for 24 hours, the conical mold is demolded; then, in sequence, 62 parts of porous mullite aggregate as the main aggregate, 23 parts of auxiliary aggregate hollow alumina microspheres, 8 parts of aluminate cement, 5 parts of silica sol, 1.93 parts of aluminosilicate fiber, and 0.07 part of aluminum powder foaming agent as the binder and additive are mixed and stirred evenly, and the bulk density is controlled at 1.5 g / cm 3Add the lightweight insulation material to the upper part of the heavy castable in the original mold. Use a vibrating rod to vibrate repeatedly twice during the pouring of the lightweight insulation material. Stop pouring when it reaches 330mm. Put 5 round steels with a diameter of 12mm and a length of 530mm horizontally into the castable. Continue pouring until it reaches 400mm and complete the pouring. Use a round wooden stick with a diameter of 30mm and a length of 50mm. Insert two sticks at each end at a distance of 120mm from the top and 350mm from the center. After 48 hours of static shaping, remove the mold and fix the angle steels with a width of 80mm and a length of 1300mm, 550mm and 400mm respectively on the upper and surrounding parts of the prefabricated block. Continue static shaping for 64 hours to complete and set for use.

[0124] Example 3

[0125] Making mold: The mold size is 1400mm long, 560mm wide, 25mm diameter of the round female buckle reserved opening, 25mm height of the insulation layer reserved opening, 340mm width, 1400mm length, 35mm diameter of the hoisting reserved opening, 50mm depth, and the diameters of the seal and gas ports from top to bottom are 380mm, 220mm and 340mm respectively. And evenly spray a certain release agent, and then mix 75 parts of brown corundum + white corundum (the mass ratio of brown corundum to the white corundum is 3:1), 10 parts of auxiliary aggregate silicon carbide powder and 12 parts of pure calcium aluminate cement, 2.85 parts of zirconium oxide fiber with an average fiber length of 4mm, and 0.15 parts of polycarboxylic acid water reducer as a binder and additives, and control the volume density to 2.3g / cm 3 The heavy castable is evenly added into the mold. During the pouring of the heavy castable, a vibrating rod is used to vibrate twice. The pouring is stopped after the pouring height reaches 280mm. After standing for 2 hours, before solidification, a transition template with a blade-shaped protrusion (blade length 560mm, upper width 40mm, lower width 20mm, depth 80mm, blade spacing 200mm) is pressed into the heavy castable and vibrated with a vibrator. After 16 hours of setting, the blade-shaped transition template is demolded; immediately after demolding, 60 parts of porous mullite aggregate of the main aggregate, 25 parts of hollow alumina microspheres of the auxiliary aggregate, 7 parts of aluminate cement, 6 parts of silica sol, 1.95 parts of aluminum silicate fiber and 0.05 parts of aluminum powder foaming agent are used as binders and additives and mixed and stirred evenly, and the volume density is controlled to be 1.45g / cm 3The lightweight heat-insulating material is added to the upper part of the heavy castable in the original mold. During the pouring of the lightweight heat-insulating material, a vibrating rod with a diameter of 50 mm is used to vibrate it repeatedly 2 times, and the lightweight heat-insulating material in the blade-shaped groove is vibrated repeatedly 3 times. The pouring is stopped when it reaches 350 mm. After horizontally placing 6 round steel bars with a diameter of 14 mm and a length of 540 mm into the castable, the pouring is continued until it reaches 450 mm to complete the pouring. Use a round wooden stick with a diameter of 35 mm and a length of 50 mm, insert two at each end at a position 120 mm from the upper part and 360 mm from the center distance. After standing and solidifying for 48 hours, the mold is removed, and angle steels with a width of 100 mm and lengths of 1400 mm, 560 mm, and 450 mm are fixed to the upper part and around the precast block. Continue to stand and solidify for 72 hours to complete, and it is ready for use.

[0126] The performance of the furnace surface precast blocks obtained in Examples 1 to 3 was measured, and the results are shown in Table 1:

[0127] Table 1 Performance of the furnace surface precast blocks obtained in Examples 1 to 3

[0128]

[0129] In addition, one or more technical solutions in the embodiments of the present application at least further have the following technical effects or advantages:

[0130] In the embodiments of the present application, a furnace surface precast block with a double-layer material structure and a preparation method thereof are provided. When building the furnace top precast block of a newly built roasting furnace or replacing the precast block during a major overhaul of the flue, the precast block made by the new method is not only beneficial to the heat preservation of the flue temperature, reduces heat loss, improves heat utilization rate, reduces the consumption of fuel natural gas, etc., saves production costs, but also is beneficial to the perfect fit with the flue furnace top brick to improve stability, durability, reduce deformation, and improve the service life of the flue.

[0131] The above are only specific embodiments of the present application, enabling those skilled in the art to understand or implement the present application. Various modifications to these embodiments will be obvious to those skilled in the art. The general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to these embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A furnace surface prefabricated block with a double-layer material structure, the furnace surface prefabricated block comprising: The lower heavy castable layer has a volume density of 2.0 g / cm 3 ~2.4g / cm 3 ; The upper layer of lightweight castable material is provided with an embedded round steel reinforcement rib, and the volume density of the castable material of the upper layer of lightweight castable material is 1.4g / cm 3 ~1.6g / cm 3 ; A transition layer is provided between the heavy castable layer and the light castable layer, wherein the transition layer is formed by embedding a concave-convex structure of the surface layer of the heavy castable layer; The combustion observation hole penetrates the heavy castable layer and the light castable layer.

2. The furnace surface prefabricated block according to claim 1, characterized in that: The furnace surface prefabricated block also includes: A reserved lifting opening is opened at the edge of the upper lightweight castable layer.

3. The furnace surface prefabricated block according to claim 2, characterized in that: The furnace surface prefabricated block also includes: A circular female buckle is arranged at the bottom of the heavy castable layer and is used for cooperating with the spigot of the fireway brick.

4. The furnace surface prefabricated block according to claim 3, characterized in that: The furnace surface prefabricated block also includes: The heat insulation opening is opened at the edge of the lightweight castable layer and is used to cooperate with the refractory fiber blanket on the upper layer of the fire channel.

5. The furnace surface prefabricated block according to claim 4, characterized in that: The furnace surface prefabricated block also includes: The fixed frame is arranged around the furnace surface prefabricated blocks, and the material of the fixed frame is angle steel.

6. The furnace surface prefabricated block according to claim 1, characterized in that: The concave-convex shape includes one or more of a boss, a cone or a blade.

7. The furnace surface prefabricated block according to claim 1, characterized in that: The upper part of the combustion observation hole is a bowl-shaped structure, and the lower part is an upper cone-shaped structure.

8. The furnace surface prefabricated block according to claim 1, characterized in that: The castable of the lower heavy castable layer includes the following chemical components by weight: 70 to 80 parts of main aggregate, 10 to 15 parts of silicon carbide powder, 8 to 12 parts of pure calcium aluminate cement, 2 to 3 parts of zirconium oxide fiber, and 0.15 to 0.25 parts of polycarboxylic acid water reducer; wherein, The main aggregate is composed of brown corundum and white corundum, and the mass ratio of the brown corundum to the white corundum is (1-3):1; The fiber length of the zirconium oxide fiber is 3 mm to 5 mm.

9. The furnace surface prefabricated block according to claim 1, characterized in that: The castable of the upper lightweight castable layer includes the following chemical components by weight: 55 to 70 parts of porous mullite aggregate, 15 to 25 parts of hollow alumina microspheres, 7 to 9 parts of aluminate cement, 4 to 6 parts of silica sol, 1.5 to 2.5 parts of aluminum silicate fiber, and 0.03 to 0.07 parts of aluminum powder foaming agent; wherein, The pore size of the porous mullite aggregate is 0.5-2 mm.

10. A method for preparing a furnace surface prefabricated block according to any one of claims 1 to 9, the method comprising: According to the size of the furnace surface prefabricated block, an overall mold, a bottom mold, a combustion observation hole mold and a transition mold are designed respectively; The bottom mold is laid under the overall mold, and the lower mold of the combustion observation hole is placed therein, and then the heavy castable is added and initially vibrated to form a lower heavy castable layer; Embedding the transition template into the surface layer of the heavy castable, and then removing the transition template to form a transition layer; Above the lower mold of the combustion observation hole, the upper mold of the combustion observation hole is placed correspondingly, and then a lightweight castable is added, and round steel reinforcement ribs are embedded to form an upper lightweight castable layer to obtain a prefabricated block semi-finished product; The semi-finished prefabricated block is cured, and then the mold is removed to obtain the furnace surface prefabricated block.

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