CN113248267B

CN113248267B - High-strength silicon carbide composite refractory brick for garbage incinerator and preparation method thereof

Info

Publication number: CN113248267B
Application number: CN202110334702.3A
Authority: CN
Inventors: 汤闻平; 常鑫童; 常伟峰
Original assignee: Yixing Haike Kiln Engineering Co ltd
Current assignee: Yixing Haike Kiln Engineering Co ltd
Priority date: 2021-03-29
Filing date: 2021-03-29
Publication date: 2022-03-25
Anticipated expiration: 2041-03-29
Also published as: CN113248267A

Abstract

The invention discloses a high-strength silicon carbide composite refractory brick for a garbage incinerator, which comprises an inner core and a refractory layer; the inner core includes: silicon carbide, clay, diatomite, bauxite, calcium aluminate cement, ferric oxide, sodium silicate, black talc, copper oxide, manganese oxide, calcite, plant ash, sulfonated lignin and pore-forming agent; the refractory layer includes: the composite material comprises electric melting ceramsite, black gold soil, fly ash, hydroxyethyl cellulose, titanium diboride, boron carbide, a dispersing agent, a silica sol solution and a foaming agent; the preparation method of the composite refractory brick comprises the following steps: s1, preparing an inner core; s2, preparing a refractory layer; s3, compounding and shaping; compounding, shaping and pressing the inner core and the refractory layer in a die to obtain a green brick; s4, sintering; respectively heating, sintering and cooling the green brick to obtain the composite refractory brick; the composite refractory brick prepared by the method has high mechanical strength and fire resistance, and is suitable for large-scale popularization.

Description

High-strength silicon carbide composite refractory brick for garbage incinerator and preparation method thereof

Technical Field

The invention relates to the technical field of refractory materials, in particular to a high-strength silicon carbide composite refractory brick for a garbage incinerator and a preparation method thereof.

Background

The garbage incinerator is used for incinerating garbage, the garbage is burnt in the hearth to become waste gas, the waste gas enters the secondary combustion chamber, the waste gas is completely combusted under the forced combustion of the combustor, and then enters the spray type dust remover, and the waste gas is discharged into the atmosphere through a chimney after dust removal. The garbage incineration is suitable for household garbage, medical garbage, general industrial garbage and the like. Compared with landfill and compost, the garbage incineration saves land and does not cause pollution to surface water and underground water.

The waste incinerator is usually required to use refractory bricks in the production process, the refractory bricks are called fire bricks for short, are refractory materials made of refractory clay or other refractory raw materials through firing, are faint yellow or brown, are mainly used for building smelting furnaces, can resist the high temperature of 1580-1770 ℃, are widely applied to high-temperature building materials and structural materials of building kilns and various thermal equipment, and are durable and solid refractory bricks. Depending on the composition of the refractory brick, it can be divided into five major categories, namely: silicon-aluminum series refractory bricks, alkaline series refractory bricks, carbon-containing refractory bricks, zirconium-containing refractory bricks and heat-insulating refractory bricks.

However, the existing refractory bricks have the following defects in the using process: 1. the strength and the high temperature resistance are not enough, and the material is easy to crack and separate in the using process; 2. the heat dissipation performance is not good, and the temperature on the refractory brick is not easy to disperse after the temperature is removed, so that the internal stress of the refractory brick is concentrated and the refractory brick is broken.

Disclosure of Invention

Aiming at the technical problems, the invention provides a high-strength silicon carbide composite refractory brick for a garbage incinerator and a preparation method thereof.

The technical scheme of the invention is as follows: a high-strength silicon carbide composite refractory brick for a garbage incinerator comprises an inner core and a refractory layer; the inner core and the fire-resistant layer are integrally fired, and the thickness ratio of the inner core to the fire-resistant layer is 8: 1-3:

the inner core comprises the following raw materials in parts by weight: 30-45 parts of silicon carbide, 12-25 parts of clay, 11-13 parts of diatomite, 5-9 parts of bauxite, 5-10 parts of calcium aluminate cement, 7-13 parts of ferric oxide, 11-18 parts of sodium silicate, 7-15 parts of black talc, 1-4 parts of copper oxide, 1-5 parts of manganese oxide, 10-13 parts of calcite, 9-15 parts of plant ash, 0.2-0.6 part of sulfonated lignin and 0.1-0.4 part of pore-forming agent;

wherein the pore-forming agent is prepared by mixing wood flour and rice hull according to the volume ratio of 1: 1;

the refractory layer comprises the following raw materials in parts by weight: 10-15 parts of electric melting ceramsite, 15-25 parts of black-gold soil, 2-4 parts of fly ash, 0.01-0.05 part of hydroxyethyl cellulose, 5-8 parts of titanium diboride, 12-14 parts of boron carbide, 0.2-1 part of dispersing agent, 0.5-1.5 parts of silica sol solution and 0.1-0.5 part of foaming agent;

wherein the foaming agent is formed by mixing silicon dioxide, polyacrylamide and polyvinyl alcohol according to the volume ratio of 2:3: 2.

A preparation method of a high-strength silicon carbide composite refractory brick for a garbage incinerator comprises the following steps:

s1, preparing an inner core;

s11, fully stirring and mixing silicon carbide, clay, diatomite, bauxite, calcium aluminate cement, ferric oxide, sodium silicate, black talc, copper oxide, manganese oxide, calcite and plant ash in a stirring kettle to obtain a mixed material;

s12, placing the mixed material obtained in the step S11 into a grinding machine, grinding for 2-5 hours, sieving the mixed material with a 80-150 mesh sieve after grinding is finished, calcining for 3-7 hours at the temperature of 350-;

s13, placing the inner core aggregate obtained in the step S12 into a reaction kettle, sequentially adding sulfonated lignin and a pore-forming agent into the reaction kettle, then adding purified water with the volume of 20-35% of the material volume into the reaction kettle, and uniformly stirring; heating the materials in the reaction kettle to 430-;

s2, preparing a refractory layer;

s21, adding the electrofused ceramsite, the wujin soil, the fly ash, the hydroxyethyl cellulose, the titanium diboride and the boron carbide into a stirring and sand mixing machine, mixing for 5-15min, then adding the dispersing agent, the silica sol solution and the foaming agent, and continuing stirring and mixing for 20-50 min;

s22, placing the mixed material obtained in the step S21 into a brick press, pressing and forming under the conditions of the temperature of 110-;

s3, compounding and shaping;

carrying out composite shaping on the inner core obtained in the step S13 and the refractory layer obtained in the step S22 in a mould, then placing the mould into a pressing machine for pressing, and controlling the pressure of the pressing machine to be 1.5-3.8t and the pressing frequency to be 3-8 times to obtain a brick blank;

s4, sintering;

firstly, placing the green brick obtained in the step S3 into a heating furnace, controlling the temperature of the heating furnace to be 500-900 ℃, heating for 1-3h, and carrying out heat preservation treatment for 5-8 h; and then placing the brick blank after the heating treatment into an electric sintering furnace filled with nitrogen atmosphere for sintering treatment, controlling the temperature of the sintering furnace to 1150-plus-one 1680 ℃, carrying out heat preservation treatment for 6-14h, finally placing the sintered brick blank into a cooling furnace, and cooling to room temperature at the cooling speed of 80-150 ℃/h to obtain the composite refractory brick.

Further, the preparation method of the electric melting ceramsite in the fire-resistant layer comprises the following steps: 1) firstly, placing the wood chips and the pulp waste liquid into a ball mill according to the mass ratio of 4:1, carrying out wet ball milling for 2-3h, and drying; 2) then adding the attapulgite, the cullet and the fly ash into a ball mill according to the mass ratio of 2:3:1, and grinding until the particle size is 400-500 meshes; 3) and finally, uniformly stirring the products of 1) and 2), placing the products into an ultrasonic dispersion instrument, uniformly dispersing, performing wet granulation, controlling the particle size to be 0.8-1.2mm, then placing the granulated materials into a muffle furnace, calcining for 0.5-1.5h at the temperature of 860-890 ℃, preserving heat for 1-2h, taking the materials out of the furnace, and cooling to normal temperature to obtain the electric-melting ceramsite.

Further, in step S12, the material-to-ball ratio in the grinding machine is 15-45:1, the grinding speed is 150-550r/min, and the combination strength of the materials in the inner core can be improved through the above arrangement, so that the compression resistance and the refractoriness of the inner core are improved.

Further, in step S13, adding the pore-forming agent into the reaction kettle for 2-5 times, wherein the time interval is 25-35min each time, and intermittently adding the pore-forming agent to uniformly distribute the pores in the inner core, thereby being beneficial to improving the high temperature resistance of the inner core.

Further, in the step S3, in the green brick pressing process, once vibration extrusion is performed for each pressing, the vibration amplitude of the vibration extrusion operation is 0.01-0.08mm, the main vibration frequency is 45-55Hz, and the vibration extrusion is performed in the green brick pressing process, so that the compactness of the green brick is more stable, and the green brick is prevented from being loose and cracked in the green brick sintering process.

Further, the specific operation of step S3 is: the pressing machine is heated to 240-500 ℃, maintained for 3-5min under the pressure of 0.5-2t, continuously heated to 500-700 ℃, maintained for 15-45min under the pressure of 2-3t, finally heated to 700-850 ℃, and maintained for 20-40min under the pressure of 3-3.8t, through the operations, the raw materials in the inner core and the fire-resistant layer tend to flow under the current pressing condition, the fusion degree of each component is increased, the heating and the pressing are uniform, the internal defect of the pressed brick blank is reduced, and the bonding strength between the materials is improved.

Further, before the step S3, a bonding agent is sprayed on the surfaces of the inner core and the refractory layer, wherein the bonding agent is a phenolic resin bonding agent, and the spraying of the bonding agent is helpful to improve the bonding strength between the inner core and the refractory layer, thereby improving the mechanical strength of the composite refractory brick.

Further, after the step S4 is completed, high-pressure airless spraying equipment is adopted to spray graphite emulsion on the surface of the composite refractory brick, the thickness of the coating is controlled to be 0.1-0.5mm, then the composite refractory brick is cured for 15-45min at the temperature of 230-580 ℃, and the graphite emulsion is sprayed on the surface of the composite refractory brick, so that the high-temperature resistance of the composite refractory brick can be improved, the composite refractory brick is prevented from cracking and falling off in the using process, and the using effect is improved.

Compared with the prior art, the invention has the beneficial effects that: the process structure of the invention is reasonable in design, the refractory brick compounded by the inner core and the heat-resistant layer ensures the strength, hardness, compression resistance and fire resistance of the refractory brick, and has high heat dissipation performance, so that the product quality of the composite refractory brick is improved, the refractory brick is prevented from cracking inside when enduring high temperature or after enduring high temperature for a long time, the service life of the composite refractory brick is prolonged, and the heat storage and heat dissipation losses of the garbage incinerator are further reduced; meanwhile, the raw materials for preparing the composite refractory brick have wide sources and low price, the production cost of the refractory brick is reduced, the bonding strength among the materials is high, and the composite refractory brick can bear larger flue gas impact force in a furnace body; the refractory brick with the porous structure has strong heat dissipation performance while ensuring the mechanical strength of the brick body, avoids the internal stress concentration and the cracking of the brick body after the furnace body is cooled down, and improves the use effect of the composite refractory brick.

Detailed Description

Example 1: a high-strength silicon carbide composite refractory brick for a garbage incinerator comprises an inner core and a refractory layer; the inner core and the fire-resistant layer are integrally fired, and the thickness ratio of the inner core to the fire-resistant layer is 8: 1:

the inner core comprises the following raw materials in parts by weight: 30 parts of silicon carbide, 12 parts of clay, 11 parts of diatomite, 5 parts of bauxite, 5 parts of calcium aluminate cement, 7 parts of ferric oxide, 11 parts of sodium silicate, 7 parts of black talc, 1 part of copper oxide, 1 part of manganese oxide, 10 parts of calcite, 9 parts of plant ash, 0.2 part of sulfonated lignin and 0.1 part of pore-forming agent;

the refractory layer comprises the following raw materials in parts by weight: 10 parts of electric melting ceramsite, 15 parts of black-gold soil, 2 parts of fly ash, 0.01 part of hydroxyethyl cellulose, 5 parts of titanium diboride, 12 parts of boron carbide, 0.2 part of dispersing agent, 0.5 part of silica sol solution and 0.1 part of foaming agent;

wherein the foaming agent is formed by mixing silicon dioxide, polyacrylamide and polyvinyl alcohol according to the volume ratio of 2:3: 2;

the electric melting ceramsite adopts a commercial product.

s1, preparing an inner core;

s12, placing the mixed material obtained in the step S11 into a grinding machine, grinding for 2 hours, sieving the mixed material with a 80-mesh sieve after grinding is completed, calcining for 3 hours at 350 ℃, standing and aging for 3 hours to obtain inner core aggregate;

s13, placing the inner core aggregate obtained in the step S12 into a reaction kettle, sequentially adding sulfonated lignin and a pore-forming agent into the reaction kettle, then adding purified water with the volume of 20% of the material volume into the reaction kettle, and uniformly stirring; heating the materials in the reaction kettle to 430 ℃, preserving heat for 20min, finally pressing and forming the materials in the reaction kettle, placing the materials in an air dryer for air drying for 35h, and controlling the water content to be 4% to obtain an inner core;

s2, preparing a refractory layer;

s21, adding the electrofused ceramsite, the wujin soil, the fly ash, the hydroxyethyl cellulose, the titanium diboride and the boron carbide into a stirring and sand mixing machine for mixing for 5min, then adding the dispersing agent, the silica sol solution and the foaming agent, and continuing stirring and mixing for 20 min;

s22, placing the mixed material obtained in the step S21 into a brick press, pressing and forming at the temperature of 110 ℃ and under the working pressure of 12MPa, and drying the formed material at the temperature of 110 ℃ for 5 hours to obtain a flame retardant coating;

s3, compounding and shaping;

carrying out composite shaping on the inner core obtained in the step S13 and the refractory layer obtained in the step S22 in a mould, then placing the mould into a pressing machine for pressing, and controlling the pressure of the pressing machine to be 1.5t and the pressing times to be 3 times to obtain a brick blank;

s4, sintering;

firstly, placing the green brick obtained in the step S3 into a heating furnace, controlling the temperature of the heating furnace to be 500 ℃, heating for 1-3h, and carrying out heat preservation treatment for 5 h; and then placing the heated green brick into an electric sintering furnace filled with nitrogen atmosphere for sintering treatment, controlling the temperature of the sintering furnace to 1150 ℃, preserving heat for 6 hours, finally placing the sintered green brick into a cooling furnace, and cooling to room temperature at the cooling rate of 80 ℃/h to obtain the composite refractory brick.

Embodiment 2, a high-strength silicon carbide composite refractory brick for a waste incinerator, the composite refractory brick comprising an inner core and a refractory layer; the inner core and the refractory layer are integrally fired, and the thickness ratio of the inner core to the refractory layer is (4: 1):

the inner core comprises the following raw materials in parts by weight: 38 parts of silicon carbide, 19 parts of clay, 12 parts of diatomite, 6 parts of bauxite, 8 parts of calcium aluminate cement, 11 parts of ferric oxide, 15 parts of sodium silicate, 12 parts of black talc, 2 parts of copper oxide, 3 parts of manganese oxide, 12 parts of calcite, 13 parts of plant ash, 0.5 part of sulfonated lignin and 0.3 part of pore-forming agent;

the refractory layer comprises the following raw materials in parts by weight: 12 parts of electric melting ceramsite, 19 parts of black-gold soil, 3 parts of fly ash, 0.04 part of hydroxyethyl cellulose, 6 parts of titanium diboride, 13 parts of boron carbide, 0.6 part of dispersing agent, 0.9 part of silica sol solution and 0.3 part of foaming agent;

the preparation method of the electric melting ceramsite comprises the following steps: 1) firstly, placing the wood chips and the pulp waste liquid into a ball mill according to the mass ratio of 4:1, carrying out wet ball milling for 2 hours, and drying; 2) then adding the attapulgite, the cullet and the fly ash into a ball mill according to the mass ratio of 2:3:1, and grinding until the particle size is 400 meshes; 3) and finally, uniformly stirring the products of 1) and 2), placing the mixture into an ultrasonic dispersion instrument, uniformly dispersing, performing wet granulation, controlling the particle size to be 0.8mm, then placing the granulated material into a muffle furnace, calcining for 0.5h at 860 ℃, preserving heat for 1h, discharging, and cooling to normal temperature to obtain the fused ceramsite.

s1, preparing an inner core;

s12, placing the mixed material obtained in the step S11 into a grinding machine, grinding for 4 hours, sieving the mixed material with a 130-mesh sieve after grinding is completed, calcining for 6 hours at 480 ℃, standing and aging for 7 hours to obtain inner core aggregate;

s13, placing the inner core aggregate obtained in the step S12 into a reaction kettle, sequentially adding sulfonated lignin and a pore-forming agent into the reaction kettle, then adding purified water with the volume of 28% of the material volume into the reaction kettle, and uniformly stirring; heating the materials in the reaction kettle to 495 ℃, preserving heat for 44min, finally pressing and forming the materials in the reaction kettle, placing the materials in an air dryer for air drying for 39h, and controlling the water content of the materials to be 6% to obtain an inner core;

s2, preparing a refractory layer;

s21, adding the electrofused ceramsite, the wujin soil, the fly ash, the hydroxyethyl cellulose, the titanium diboride and the boron carbide into a stirring and sand mixing machine for mixing for 9min, then adding the dispersing agent, the silica sol solution and the foaming agent, and continuing stirring and mixing for 45 min;

s22, placing the mixed material obtained in the step S21 into a brick press, pressing and forming at the temperature of 156 ℃ and under the working pressure of 14MPa, and drying the formed material at the temperature of 235 ℃ for 13 hours to obtain a flame retardant coating;

s3, compounding and shaping;

carrying out composite shaping on the inner core obtained in the step S13 and the refractory layer obtained in the step S22 in a mould, then placing the mould into a pressing machine for pressing, controlling the pressure of the pressing machine to be 2.6t, and controlling the pressing times to be 5 times to obtain a brick blank;

s4, sintering;

firstly, placing the green brick obtained in the step S3 into a heating furnace, controlling the temperature of the heating furnace to be 695 ℃, heating for 2 hours, and carrying out heat preservation treatment for 7 hours; and then placing the brick blank subjected to the heating treatment into an electric sintering furnace filled with nitrogen atmosphere for sintering treatment, controlling the temperature of the sintering furnace to 1450 ℃, performing heat preservation treatment for 11 hours, finally placing the sintered brick blank into a cooling furnace, and cooling to room temperature at the cooling speed of 110 ℃/h to obtain the composite refractory brick.

Embodiment 3, a high-strength silicon carbide composite refractory brick for a waste incinerator, comprising an inner core and a refractory layer; the inner core and the refractory layer are integrally fired, and the thickness ratio of the inner core to the refractory layer is (8: 3):

the inner core comprises the following raw materials in parts by weight: 45 parts of silicon carbide, 25 parts of clay, 13 parts of diatomite, 9 parts of bauxite, 10 parts of calcium aluminate cement, 13 parts of ferric oxide, 18 parts of sodium silicate, 15 parts of black talc, 4 parts of copper oxide, 5 parts of manganese oxide, 13 parts of calcite, 15 parts of plant ash, 0.6 part of sulfonated lignin and 0.4 part of pore-forming agent;

the refractory layer comprises the following raw materials in parts by weight: 15 parts of electric melting ceramsite, 25 parts of black-gold soil, 4 parts of fly ash, 0.05 part of hydroxyethyl cellulose, 8 parts of titanium diboride, 14 parts of boron carbide, 1 part of dispersing agent, 1.5 parts of silica sol solution and 0.5 part of foaming agent;

the electric melting ceramsite adopts a commercial product.

s1, preparing an inner core;

s12, placing the mixed material obtained in the step S11 into a grinding machine, grinding for 5 hours, sieving the mixed material with a 150-mesh sieve after grinding is completed, calcining for 7 hours at 700 ℃, standing and aging for 9 hours to obtain inner core aggregate; the material-ball ratio in the grinding machine is 15:1, the grinding speed is 150r/min, and the bonding strength of each material in the inner core can be improved through the arrangement, so that the compression resistance and the refractoriness of the inner core are improved;

s13, placing the inner core aggregate obtained in the step S12 into a reaction kettle, sequentially adding sulfonated lignin and a pore-forming agent into the reaction kettle, then adding purified water with the volume of 35% of the material volume into the reaction kettle, and uniformly stirring; heating the materials in the reaction kettle to 560 ℃, preserving heat for 50min, finally pressing and forming the materials in the reaction kettle, placing the materials in an air dryer for air drying for 45h, and controlling the water content to be 8% to obtain an inner core; wherein, the pore-forming agent is added into the reaction kettle for 2 times, the time interval of each time is 35min, and the pores in the inner core are uniformly distributed by intermittently adding the pore-forming agent, which is beneficial to improving the high temperature resistance of the inner core;

s2, preparing a refractory layer;

s21, adding the electrofused ceramsite, the wujin soil, the fly ash, the hydroxyethyl cellulose, the titanium diboride and the boron carbide into a stirring and sand mixing machine for mixing for 15min, then adding the dispersing agent, the silica sol solution and the foaming agent, and continuing stirring and mixing for 50 min;

s22, placing the mixed material obtained in the step S21 into a brick press, pressing and forming at the temperature of 180 ℃ and under the working pressure of 15MPa, and drying the formed material at the temperature of 260 ℃ for 18 hours to obtain a flame retardant coating;

s3, compounding and shaping;

carrying out composite shaping on the inner core obtained in the step S13 and the refractory layer obtained in the step S22 in a mould, then placing the mould into a pressing machine for pressing, controlling the pressure of the pressing machine to be 3.8t, and controlling the pressing times to be 8 times to obtain a brick blank;

s4, sintering;

firstly, placing the green bricks obtained in the step S3 into a furnace, controlling the temperature of the heating furnace to be 900 ℃, heating for 3 hours, and carrying out heat preservation treatment for 8 hours; and then placing the brick blank after the heating treatment into an electric sintering furnace filled with nitrogen atmosphere for sintering treatment, controlling the temperature of the sintering furnace to be 1680 ℃, carrying out heat preservation treatment for 14h, finally placing the sintered brick blank into a cooling furnace, and cooling to room temperature at the cooling speed of 150 ℃/h to obtain the composite refractory brick.

Embodiment 4, a high-strength silicon carbide composite refractory brick for a waste incinerator, the composite refractory brick comprising an inner core and a refractory layer; the inner core and the fire-resistant layer are integrally fired, and the thickness ratio of the inner core to the fire-resistant layer is 8: 1:

the electric melting ceramsite adopts a commercial product.

s1, preparing an inner core;

s12, placing the mixed material obtained in the step S11 into a grinding machine, grinding for 2 hours, sieving the mixed material with a 80-mesh sieve after grinding is completed, calcining for 3 hours at 350 ℃, standing and aging for 9 hours to obtain inner core aggregate;

s2, preparing a refractory layer;

s3, compounding and shaping;

respectively spraying a bonding agent on the inner core obtained in the step S13 and the surface of the refractory layer obtained in the step S22, wherein the bonding agent is a phenolic resin bonding agent, the spraying of the bonding agent is helpful for improving the bonding strength of the inner core and the refractory layer, so as to improve the mechanical strength of the composite refractory brick, then carrying out composite shaping on the inner core and the refractory layer in a mold, then placing the mold into a pressing machine for pressing, heating the pressing machine to 240 ℃, maintaining for 3min under the pressure of 0.5t, continuing heating to 500 ℃, maintaining for 15min under the pressure of 2t, finally heating to 700 ℃, maintaining for 20min under the pressure of 3t to obtain a brick blank, and through the operations, the raw materials in the inner core and the refractory layer are consistent in fluidity under the current pressing condition, the fusion degree of each component is increased, the heating and the pressing are uniform, the internal defect of the pressed brick blank is reduced, and the bonding strength between the materials is improved; in the green brick pressing process, once vibration extrusion operation is carried out once, the vibration amplitude of the vibration extrusion operation is 0.01mm, the main vibration frequency is 45Hz, and the vibration extrusion is carried out in the green brick pressing process, so that the compactness of the green brick is more stable, and loose cracking in the green brick sintering process is avoided;

s4, sintering;

firstly, placing the green brick obtained in the step S3 into a heating furnace, controlling the temperature of the heating furnace to be 500 ℃, heating for 1h, and carrying out heat preservation treatment for 5 h; and then placing the heated green brick into an electric sintering furnace filled with nitrogen atmosphere for sintering treatment, controlling the temperature of the sintering furnace to 1150 ℃, preserving heat for 6 hours, finally placing the sintered green brick into a cooling furnace, and cooling to room temperature at the cooling rate of 80 ℃/h to obtain the composite refractory brick.

Example 5 a high-strength silicon carbide composite refractory brick for a waste incinerator, the composite refractory brick comprising an inner core and a refractory layer; the inner core and the refractory layer are integrally fired, and the thickness ratio of the inner core to the refractory layer is (4: 1):

the electric melting ceramsite adopts a commercial product.

s1, preparing an inner core;

s12, placing the mixed material obtained in the step S11 into a grinding machine, grinding for 4 hours, sieving with a 135-mesh sieve after the mixed material is ground, calcining for 6 hours at 490 ℃, standing and aging for 7 hours to obtain inner core aggregate;

s13, placing the inner core aggregate obtained in the step S12 into a reaction kettle, sequentially adding sulfonated lignin and a pore-forming agent into the reaction kettle, then adding purified water with the volume of 28% of the material volume into the reaction kettle, and uniformly stirring; heating the materials in the reaction kettle to 520 ℃, preserving heat for 35min, finally pressing and forming the materials in the reaction kettle, placing the materials in an air dryer for air drying for 41h, and controlling the water content to be 7% to obtain an inner core;

s2, preparing a refractory layer;

s21, adding the electrofused ceramsite, the wujin soil, the fly ash, the hydroxyethyl cellulose, the titanium diboride and the boron carbide into a stirring and sand mixing machine, mixing for 11min, then adding the dispersing agent, the silica sol solution and the foaming agent, and continuing stirring and mixing for 39 min;

s22, placing the mixed material obtained in the step S21 into a brick press, performing compression molding at the temperature of 148 ℃ and the working pressure of 14MPa, and drying the molded material at the temperature of 195 ℃ for 13 hours to obtain a flame retardant coating;

s3, compounding and shaping;

carrying out composite shaping on the inner core obtained in the step S13 and the refractory layer obtained in the step S22 in a mould, then placing the mould into a pressing machine for pressing, controlling the pressure of the pressing machine to be 2.5t, and controlling the pressing times to be 6 times to obtain a brick blank;

s4, sintering;

firstly, placing the green brick obtained in the step S3 into a heating furnace, controlling the temperature of the heating furnace to be 650 ℃, heating for 2 hours, and carrying out heat preservation treatment for 6 hours; and then placing the brick blank after the heating treatment into an electric sintering furnace filled with nitrogen atmosphere for sintering treatment, controlling the temperature of the sintering furnace to be 1560 ℃, carrying out heat preservation treatment for 11 hours, finally placing the sintered brick blank into a cooling furnace, cooling to room temperature at the cooling speed of 95 ℃/h to obtain the composite refractory brick, spraying graphite emulsion on the surface of the composite refractory brick by adopting high-pressure airless spraying equipment, controlling the thickness of the coating to be 0.4mm, then curing the composite refractory brick for 32min at the temperature of 430 ℃, and spraying the graphite emulsion on the surface of the composite refractory brick, so that the high-temperature resistance of the composite refractory brick can be improved, the composite refractory brick is prevented from cracking and falling off in the using process, and the use effect is improved.

Example 6 a high-strength silicon carbide composite refractory brick for a waste incinerator, the composite refractory brick comprising an inner core and a refractory layer; the inner core and the refractory layer are integrally fired, and the thickness ratio of the inner core to the refractory layer is (8: 3):

the preparation method of the electric melting ceramsite in the fire-resistant layer comprises the following steps: 1) firstly, placing the wood chips and the pulp waste liquid into a ball mill according to the mass ratio of 4:1, carrying out wet ball milling for 3 hours, and drying; 2) then adding the attapulgite, the cullet and the fly ash into a ball mill according to the mass ratio of 2:3:1, and grinding until the particle size is 500 meshes; 3) and finally, uniformly stirring the products of 1) and 2), placing the products into an ultrasonic dispersion instrument, uniformly dispersing the products, performing wet granulation, controlling the particle size to be 1.2mm, then placing the granulated materials into a muffle furnace, calcining the materials for 1.5h at 890 ℃, preserving the heat for 2h, discharging the materials from the furnace, and cooling the materials to the normal temperature to obtain the electric-melting ceramsite.

s1, preparing an inner core;

s12, placing the mixed material obtained in the step S11 into a grinding machine, grinding for 5 hours, sieving the mixed material with a 150-mesh sieve after grinding is completed, calcining for 7 hours at 700 ℃, standing and aging for 9 hours to obtain inner core aggregate; the material-ball ratio in the grinding machine is 45:1, the grinding speed is 550r/min, and the bonding strength of each material in the inner core can be improved through the arrangement, so that the compression resistance and the refractoriness of the inner core are improved;

s13, placing the inner core aggregate obtained in the step S12 into a reaction kettle, sequentially adding sulfonated lignin and a pore-forming agent into the reaction kettle, then adding purified water with the volume of 35% of the material volume into the reaction kettle, and uniformly stirring; heating the materials in the reaction kettle to 560 ℃, preserving heat for 50min, finally pressing and forming the materials in the reaction kettle, placing the materials in an air dryer for air drying for 45h, and controlling the water content to be 8% to obtain an inner core; wherein, the pore-forming agent is added into the reaction kettle for 5 times, the time interval of each time is 35min, and the pores in the inner core are uniformly distributed by intermittently adding the pore-forming agent, which is beneficial to improving the high temperature resistance of the inner core;

s2, preparing a refractory layer;

s3, compounding and shaping;

s4, sintering;

firstly, placing the green brick obtained in the step S3 into a heating furnace, controlling the temperature of the heating furnace to be 900 ℃, heating for 3 hours, and carrying out heat preservation treatment for 8 hours; and then placing the brick blank after the heating treatment into an electric sintering furnace filled with nitrogen atmosphere for sintering treatment, controlling the temperature of the sintering furnace to be 1680 ℃, carrying out heat preservation treatment for 14h, finally placing the sintered brick blank into a cooling furnace, and cooling to room temperature at the cooling speed of 150 ℃/h to obtain the composite refractory brick.

Example 7 a high-strength silicon carbide composite refractory brick for a waste incinerator, comprising an inner core and a refractory layer; the inner core and the refractory layer are integrally fired, and the thickness ratio of the inner core to the refractory layer is (8: 3):

s1, preparing an inner core;

s13, placing the inner core aggregate obtained in the step S12 into a reaction kettle, sequentially adding sulfonated lignin and a pore-forming agent into the reaction kettle, then adding purified water with the volume of 35% of the material volume into the reaction kettle, and uniformly stirring; heating the materials in the reaction kettle to 560 ℃, preserving heat for 50min, finally pressing and forming the materials in the reaction kettle, placing the materials in an air dryer for air drying for 45h, and controlling the water content to be 8% to obtain an inner core; adding the pore-forming agent into the reaction kettle for 5 times, wherein the time interval of each time is 35min, and intermittently adding the pore-forming agent to ensure that pores in the inner core are uniformly distributed, thereby being beneficial to improving the high-temperature resistance of the inner core;

s2, preparing a refractory layer;

s3, compounding and shaping;

respectively spraying a bonding agent on the inner core obtained in the step S13 and the surface of the refractory layer obtained in the step S22, wherein the bonding agent is a phenolic resin bonding agent, the spraying of the bonding agent is helpful for improving the bonding strength of the inner core and the refractory layer, so as to improve the mechanical strength of the composite refractory brick, then carrying out composite shaping on the inner core and the refractory layer in a mold, then placing the mold into a pressing machine for pressing, heating the pressing machine to 500 ℃, maintaining for 5min under the pressure of 2t, continuing heating to 700 ℃, maintaining for 45min under the pressure of 3t, finally heating to 850 ℃, maintaining for 40min under the pressure of 3.8t to obtain a brick blank, and through the operations, the raw materials in the inner core and the refractory layer are consistent in fluidity under the current pressing condition, the fusion degree of each component is increased, the heating and the pressing are uniform, the internal defect of the pressed brick blank is reduced, and the bonding strength between the materials is improved; in the green brick pressing process, once vibration extrusion operation is carried out once, the vibration amplitude of the vibration extrusion operation is 0.08mm, the main vibration frequency is 55Hz, and the vibration extrusion is carried out in the green brick pressing process, so that the compactness of the green brick is more stable, and loose cracking in the green brick sintering process is avoided;

s4, sintering;

firstly, placing the green brick obtained in the step S3 into a heating furnace, controlling the temperature of the heating furnace to be 900 ℃, heating for 13 hours, and carrying out heat preservation treatment for 8 hours; then placing the brick blank after the heating treatment into an electric sintering furnace filled with nitrogen atmosphere for sintering treatment, controlling the temperature of the sintering furnace to be 1680 ℃, carrying out heat preservation treatment for 14h, finally placing the sintered brick blank into a cooling furnace, and cooling to room temperature at the cooling speed of 150 ℃/h to obtain the composite refractory brick; the high-temperature resistant performance of the composite refractory brick can be improved, the composite refractory brick is prevented from cracking and falling off in the using process, and the using effect is improved.

Test example: the composite refractory bricks obtained in examples 1 to 7 and conventional ordinary refractory bricks were tested for their respective performances, and the test results are shown in Table 1;

table 1: detecting the related performance detection results of the composite refractory bricks and the common refractory bricks under different conditions;

as can be seen from the comparison of the data in table 1, in example 2, the mechanical strength and refractoriness of the refractory layer are further enhanced and the strength of the composite refractory brick is improved due to the adoption of the electrofused ceramsite prepared by the method of the present invention;

in the embodiment 3, the material-ball ratio in the grinding machine is controlled to be 15:1, the grinding speed is 150r/min, and the pore-forming agent is controlled to be added into the reaction kettle for 2 times, wherein the time interval of each time is 35min, so that the bonding strength of each material in the inner core is improved, and the compression resistance and the high-temperature resistance of the inner core are further improved;

in the embodiment 4, the bonding agent is sprayed in the process of compounding the inner core and the refractory layer, so that the bonding strength of the inner core and the refractory layer is improved, the mechanical strength of the composite refractory brick is further improved, and the inner core and the refractory layer are pressed at different pressures, so that the flowability of raw materials in the inner core and the refractory layer is converged under the current pressing condition, the fusion degree of each component is increased, the heating and the pressing are uniform, the internal defect of a pressed brick blank is reduced, and the bonding strength between the materials is improved; the vibration extrusion in the green brick pressing process enables the compactness of the green brick to be more stable, and loose cracking in the green brick sintering process is avoided.

In the embodiment 5, as the graphite emulsion is sprayed on the surface of the composite refractory brick, the high-temperature resistance of the composite refractory brick can be improved, the composite refractory brick is prevented from cracking and falling off in the use process, and the use effect is improved;

in the embodiment 6, the electrofused ceramsite prepared by the method is adopted, and the pore-forming agent is added into the reaction kettle in several times, so that the bonding strength of each material in the inner core is improved, and the compression resistance and the high temperature resistance of the inner core are further improved;

in example 7, the conditions in each step were comprehensively optimized, so that the properties of the obtained composite refractory brick were further improved.

Claims

1. The high-strength silicon carbide composite refractory brick for the garbage incinerator is characterized by comprising an inner core and a refractory layer; the inner core and the fire-resistant layer are integrally fired, and the thickness ratio of the inner core to the fire-resistant layer is 8: 1-3:

the pore-forming agent is prepared by mixing wood flour and rice hulls according to the volume ratio of 1: 1;

the refractory layer comprises the following raw materials in parts by weight: 10-15 parts of electric melting ceramsite, 15-25 parts of black-gold soil, 2-4 parts of fly ash, 0.01-0.05 part of hydroxyethyl cellulose, 5-8 parts of titanium diboride, 12-14 parts of boron carbide, 0.2-1 part of dispersing agent, 0.5-1.5 parts of silica sol solution and 0.1-0.5 part of foaming agent; the preparation method of the electric melting ceramsite comprises the following steps: 1) firstly, placing the wood chips and the pulp waste liquid into a ball mill according to the mass ratio of 4:1, carrying out wet ball milling for 2-3h, and drying; 2) then adding the attapulgite, the cullet and the fly ash into a ball mill according to the mass ratio of 2:3:1, and grinding until the particle size is 400-500 meshes; 3) finally, uniformly stirring the products of 1) and 2), placing the products into an ultrasonic dispersion instrument, uniformly dispersing, performing wet granulation, controlling the particle size to be 0.8-1.2mm, then placing the granulated materials into a muffle furnace, calcining for 0.5-1.5h at the temperature of 860-890 ℃, preserving heat for 1-2h, and cooling to normal temperature after discharging to obtain the electric-melting ceramsite;

the foaming agent is prepared by mixing silicon dioxide, polyacrylamide and polyvinyl alcohol according to the volume ratio of 2:3: 2;

the preparation method of the composite refractory brick comprises the following steps:

s1, preparing an inner core;

s11, fully stirring and mixing the silicon carbide, the clay, the diatomite, the bauxite, the calcium aluminate cement, the ferric oxide, the sodium silicate, the black talc, the copper oxide, the manganese oxide, the calcite and the plant ash in a stirring kettle to obtain a mixed material;

s2, preparing a refractory layer;

s21, adding the electrofused ceramsite, the black-gold soil, the fly ash, the hydroxyethyl cellulose, the titanium diboride and the boron carbide into a stirring and sand mixing machine, mixing for 5-15min, then adding the dispersing agent, the silica sol solution and the foaming agent, and continuing stirring and mixing for 20-50 min;

s22, placing the mixed material obtained in the step S21 into a brick press, pressing and molding the mixed material at the temperature of 110-;

s3, compounding and shaping;

s4, sintering;

firstly, placing the green brick obtained in the step S3 into a heating furnace, controlling the temperature of the heating furnace to be 500-900 ℃, heating for 1-3h, and carrying out heat preservation treatment for 5-8 h; then placing the brick blank after the heating treatment into an electric sintering furnace filled with nitrogen atmosphere for sintering treatment, controlling the temperature of the sintering furnace to 1150-plus-one 1680 ℃, carrying out heat preservation treatment for 6-14h, finally placing the sintered brick blank into a cooling furnace, and cooling to room temperature at the cooling speed of 80-150 ℃/h to obtain the composite refractory brick;

in step S12, the material ball ratio in the grinder is 15-45:1, and the grinding speed is 150-;

in the step S13, the pore-forming agent is added into the reaction kettle for 2-5 times, and the time interval of each time is 25-35 min;

in the step S3, in the green brick pressing process, once pressing, carrying out vibration extrusion operation, wherein the vibration amplitude of the vibration extrusion operation is 0.01-0.08mm, and the main vibration frequency is 45-55 Hz;

the specific operation of step S3 is: heating the pressing machine to 240-500 ℃, maintaining for 3-5min at the pressure of 0.5-2t, continuing to heat to 500-700 ℃, maintaining for 15-45min at the pressure of 2-3t, finally heating to 700-850 ℃, and maintaining for 20-40min at the pressure of 3-3.8 t;

before the step S3, respectively spraying a bonding agent on the surfaces of the inner core and the fire-resistant layer, wherein the bonding agent is a phenolic resin bonding agent;

and step S4, spraying graphite emulsion on the surface of the composite refractory brick by using high-pressure airless spraying equipment, controlling the thickness of the coating to be 0.1-0.5mm, and curing the composite refractory brick at the temperature of 230-580 ℃ for 15-45 min.