CN111908943A

CN111908943A - Preparation method of hollow brick with excellent thermal insulation performance

Info

Publication number: CN111908943A
Application number: CN202010786529.6A
Authority: CN
Inventors: 艾明生
Original assignee: Hexian Mingsheng Environmental Protection Material Co ltd
Current assignee: Hexian Mingsheng Environmental Protection Material Co ltd
Priority date: 2020-08-07
Filing date: 2020-08-07
Publication date: 2020-11-10

Abstract

The invention relates to the technical field of preparation of novel building materials, and discloses a preparation method of a hollow brick with excellent thermal insulation performance, wherein the preparation method ensures the strength of a brick body under the condition of improving the thermal insulation performance of the hollow brick by proportioning raw materials for preparing the hollow brick and controlling the conditions in the sintering process, and has the characteristics of low cost, low energy consumption and high performance; the invention gives full play to the raw material price and energy-saving advantage of the coal gangue, the prepared pore-forming agent is doped into the brick raw material, the porosity and compressive strength of the hollow brick can be improved by controlling the doping amount, the heat conductivity coefficient of the hollow brick is reduced, the requirement of energy-saving and heat-preservation is met, the problem that the plasticity of the brick-making raw material is reduced by adding the existing pore-forming agent, so that the porosity and mechanical strength of the sintered brick are reduced is solved, the heat conductivity coefficient of the prepared heat-preservation sintered hollow brick is obviously reduced, and the heat conductivity coefficient is as low as 0.19-0.21W/m.k.

Description

Preparation method of hollow brick with excellent thermal insulation performance

Technical Field

The invention belongs to the technical field of preparation of novel building materials, and particularly relates to a preparation method of an air brick with excellent thermal insulation performance.

Background

The bricks are various in types and are divided into clay bricks, shale bricks, gangue bricks, fly ash bricks, sand-lime bricks, slag bricks and the like according to the used raw materials; according to the production process, the brick can be divided into a sintered brick and a non-sintered brick. The baked brick has thousands of development histories in China, and the baked brick is: bricks for building load-bearing and non-load-bearing walls, which are prepared from clay, shale, coal gangue or fly ash as raw materials through molding and high-temperature roasting, are collectively called as baked bricks. Due to the exhaustion of resources and the deepening of environmental pollution, the traditional clay brick sintering process is banned, and the demand of the air brick in China is still large.

With the rapid development of economy in China, the consumption of the building industry accounts for the greatest proportion and the increase speed is the fastest among various energy consumption. If the clay is continuously used for producing the baked brick, the land resource is necessarily reduced, and the agricultural production activity is influenced.

In order to respond to the requirements of energy conservation, water conservation, land consolidation, material consolidation and environmental protection, the improvement of the heat-insulating property of the wall material becomes the pursuit target of enterprise production. At present, the self heat insulation performance of the hollow brick is not good enough, and the requirement of the heat insulation and energy saving effect of the outer wall building in application can not be met.

Disclosure of Invention

The invention aims to provide a preparation method of an air brick with excellent thermal insulation performance aiming at the existing problems, so that the thermal conductivity coefficient of the air brick is reduced, and the thermal insulation performance of the air brick is improved.

The invention is realized by the following technical scheme:

a preparation method of an air brick with excellent heat insulation performance specifically comprises the following process steps:

mixing the gangue after being sorted and removing impurities with the fly ash raw material according to the mass ratio of 5-6:3-4, finely crushing the gangue and the fly ash raw material by using a crusher until the gangue and the fly ash raw material pass through a 0.8-1.0 mm sieve, adding water while stirring, adjusting the water content of a mud mass to be 14-16%, then adding shale powder with the mass fraction of 7-11% of the mass of the mud mass, uniformly mixing and stirring the shale powder, performing heat treatment at the temperature of 130 ℃ and 160 ℃ for 8-10 hours, further finely crushing the shale powder until the shale powder passes through the 0.1-0.2 mm sieve, then putting the mixture into a stirring barrel, adding a pore-forming agent with the mass fraction of 1.4-1.6% of the mass of the mixture, uniformly stirring and mixing the mixture, adding water and uniformly stirring the mixture, aging the mixture for 40-48 hours, pouring the mixture into a stirrer for stirring and mixing, then putting the mixture into a hydraulic extruder for extrusion, placing the brick blank on a tray for drying for 6-8 hours, maintaining the brick blank for 10-16 hours at the air relative humidity of 80-85% and the temperature of 55-60 ℃, then placing the brick blank in an electric heating blowing drying box at the temperature of 135-145 ℃ for drying to constant weight, wherein the flow rate of a drying medium is 2.5-3.0 m/s, placing the dried brick blank in an electric furnace preheated at the temperature of 280-300 ℃ for heating and roasting, adopting an intermittent heating mode, heating the brick blank to the temperature of 580-50 minutes at the heating speed of 2.5-3.0 ℃/minute in the first stage, heating the brick blank to the temperature of 900-930 ℃ at the heating speed of 1.0-1.2 ℃/minute in the second stage, performing heat preservation and roasting for 120 minutes at the heating speed of 100-930 ℃, and then naturally cooling the brick blank to the room temperature; the shale powder is prepared by crushing shale until the crushed shale passes through a 0.6-1.0 mm sieve and drying, and the water content of the material before aging is 12-16%.

The preparation method of the pore-forming agent comprises the following steps:

(1) grinding gypsum into powder, mixing the powder with basalt fibers with the length of 2-5 mm according to the mass ratio of 17-20:2-3, adding 30-40% of sodium silicate aqueous solution with the mass fraction of 0.4-0.5% into the mixture, continuously stirring for 18-22 minutes at the speed of 150-160 revolutions/minute, then adding 1.8-2.0 times of volume of water, quickly stirring at the stirring speed of 500-600 revolutions/minute for 30-40 minutes, and standing the obtained mixed material for 15-20 hours at the temperature of 110-115 ℃ and the humidity of 93-95%;

(2) taking out the material obtained in the step (1), stirring and dispersing, adding montmorillonite and silica aerogel with the mass fractions of 4.5-5.5% and 2.0-2.3% respectively, wherein the particle size of the silica aerogel is between 80-120 nm, continuously stirring for 25-30 min, standing for 4-5 h, drying in an oven at 80-90 ℃ for 4-6 h, transferring to a muffle furnace, heating to 650 plus materials and 680 ℃, carrying out heat preservation and calcination for 70-80 min, naturally cooling to room temperature along with the furnace, grinding to pass through a 150 plus materials and 160 mesh sieve to obtain the pore-forming agent, dispersing the pore-forming agent into coal gangue, controlling the doping amount to improve the porosity and compressive strength of the hollow brick, reduce the heat conductivity of the hollow brick, meet the requirements of energy conservation and heat preservation, and solve the problem that the plasticity of brick making raw materials can be reduced due to the addition of the existing pore-forming agent, the method has the advantages that the porosity and the mechanical strength of the sintered brick are reduced, the sintering speed is accelerated in sintering, a new phase is formed with the components of a green brick matrix, the strength of the hollow brick is improved, the drying shrinkage rate is reduced, and cracks are not easy to generate in use.

Compared with the prior art, the invention has the following advantages: in order to solve the problem that the hollow brick has poor heat insulation performance, the invention provides a preparation method of the hollow brick with excellent heat insulation performance, the strength of the brick body is ensured under the condition of improving the heat insulation performance of the hollow brick by proportioning the preparation raw materials of the hollow brick and controlling the conditions of the sintering process, and the preparation method has the characteristics of low cost, low energy consumption and high performance; the invention gives full play to the raw material price and energy-saving advantage of the coal gangue, the prepared pore-forming agent is mixed and filled in the gaps of the hollow bricks, the thermal resistance of an air interlayer is improved, the heat loss caused by heat conduction is reduced, the thermal conductivity coefficient of the prepared heat-insulating sintered hollow brick is obviously reduced, the thermal conductivity coefficient is as low as 0.19-0.21W/m.k, the porosity is within the range of 50-53%, the density is within the range of 0.80-0.82kg/dm3, the compressive strength reaches 21-25MPa, the drying shrinkage rate is 4.8-5.0%, the heat-insulating sintered hollow brick has excellent heat-insulating and energy-saving performance and higher compressive strength, the heat-insulating performance of the hollow brick as a wall material is effectively improved, the energy-saving standard requirement is met, the energy consumption is saved, the production cost is reduced, the heat-insulating and energy-saving hollow brick has wide application prospect, and a foundation is laid for the research of novel light and.

Drawings

In order to facilitate understanding for those skilled in the art, the present invention will be further described with reference to the accompanying drawings.

FIG. 1 is a graph comparing the effect of the use of pore formers of the present invention and a control pore former on the compressive strength of an air brick.

Detailed Description

In order to make the objects, technical solutions and effects of the present invention clearer and clearer, the present invention is further described with reference to specific embodiments, and it should be understood that the specific embodiments described herein are only used for explaining the present invention and are not used for limiting the technical solutions provided by the present invention.

Example 1

A preparation method of a heat-insulating hollow brick comprises the following steps: mixing the gangue after being sorted and removing impurities with the fly ash according to the mass ratio of 5:3, finely crushing the gangue and the fly ash by using a crusher until the gangue and the fly ash pass through a 0.8 mm sieve, adding water while stirring, adjusting the water content of a mud mass to be between 14 and 16 percent, then adding shale powder with the mass fraction of 7 percent of the mass of the mud mass, uniformly mixing and stirring, placing the mixture at 130 ℃ for heat treatment for 8 hours, further finely crushing the mixture until the shale powder passes through the 0.1 mm sieve, then placing the material into a stirring barrel, adding pore-forming agent with the mass fraction of 1.4 percent of the mass of the material, uniformly stirring and mixing, adding water, uniformly stirring, aging for 40 hours, pouring the mixture into a stirrer, stirring and mixing, then placing the mixture into a hydraulic extruder for extrusion molding, wherein the molding pressure is 2.0MPa, manually cutting the extruded mixture, placing the extruded mixture on a tray for drying for 6 hours, maintaining the mixture at the air relative humidity of 80 percent and the temperature, the flow rate of a drying medium is 2.5 m/s, the dried green brick is placed in an electric furnace preheated at 280 ℃ for heating and roasting, an intermittent heating mode is adopted, the temperature is raised to 58 ℃ at the speed of 2.5 ℃/min in the first stage, the temperature is kept for 40 min, the temperature is raised to 900 ℃ at the speed of 1.0 ℃/min in the second stage, the temperature is kept and the roasting is carried out for 100 min, and then the green brick is naturally cooled to the room temperature; the shale powder is prepared by crushing shale until the crushed shale passes through a 0.6 mm sieve and drying, and the water content of the material before aging is between 12 and 16 percent.

Further, the preparation method of the pore-forming agent comprises the following steps:

(1) grinding gypsum into powder, mixing the powder with basalt fibers with the length of 2-5 mm according to the mass ratio of 17:2, adding 30% of sodium silicate aqueous solution with the mass fraction of 0.4% into the mixture, continuously stirring for 18 minutes at the speed of 150 revolutions per minute, then adding 1.8 times of volume of water, quickly stirring at the speed of 500 revolutions per minute for 30 minutes, and standing the obtained mixed material for 15 hours at the temperature of 110 ℃ and the humidity of 93%;

(2) and (2) taking out the material obtained in the step (1), stirring and dispersing, adding montmorillonite and silica aerogel with the mass fractions of 4.5% and 2.0% respectively, wherein the particle size of the silica aerogel is between 80 and 120 nanometers, continuously stirring for 25 minutes, standing for 4 hours, drying in an oven at 80 ℃ for 4 hours, transferring to a muffle furnace, heating to 650 ℃, carrying out heat preservation and calcination for 70 minutes, naturally cooling to room temperature along with the furnace, and grinding to 150-mesh sieve to obtain the pore-forming agent.

The coal gangue and fly ash are from Qidong coal mine in Anhui dormiton, and the shale is selected from mine area around the mine.

A test piece of a hollow brick having a size of 190 mm. times.100 mm. times.60 mm was produced according to the production method of example 1, and the thermal conductivity of the sintered hollow brick was measured by a heat flow meter type thermal conductivity meter, and the test procedure was carried out with reference to GB/T10295-2008, and the test piece had a thermal conductivity of 0.21W/m.k, a porosity of 52% and a density of 0.81kg/dm 3.

Other properties: the mechanical properties of the samples are measured, the average level of 10 samples is taken, and the test standard is carried out by the method of GB13544-2000 and GB/T2542-92, and the results are obtained: the compressive strength reaches 23.5MPa, and the drying shrinkage rate is 4.9%.

Example 2

A preparation method of a heat-insulating hollow brick comprises the following steps: mixing the gangue after being sorted and removing impurities with the fly ash according to the mass ratio of 5.5:3.5, finely crushing the gangue and the fly ash by using a crusher until the gangue and the fly ash pass through a 0.9 mm sieve, adding water while stirring, adjusting the water content of a mud mass to be 14-16%, then adding shale powder with the mass fraction of 8.5% of the mass of the mud mass, uniformly mixing and stirring the shale powder, placing the mixture at 145 ℃ for heat treatment for 9 hours, further finely crushing the shale powder until the shale powder passes through a 0.15 mm sieve, then placing the material into a stirring barrel, adding a pore-forming agent with the mass fraction of 1.5% of the mass of the material, uniformly stirring and mixing the shale powder, adding water and stirring the mixture uniformly, aging the mixture for 44 hours, pouring the mixture into a stirrer for stirring and mixing, then placing the mixture into a hydraulic extruder for extrusion molding, wherein the molding pressure is 2.2MPa, the extrusion is manually cut after extrusion, placing the mixture on a tray for drying for 7 hours, maintaining the mixture at the, the flow rate of a drying medium is 2.8 m/s, the dried green brick is placed in an electric furnace preheated at 290 ℃ for heating and roasting, an intermittent heating mode is adopted, the temperature is raised to 590 ℃ at the heating rate of 2.8 ℃/min in the first stage, the temperature is kept for 45 min, the temperature is raised to 915 ℃ at the heating rate of 1.1 ℃/min in the second stage, the temperature is kept for calcining for 110 min, and then the green brick is naturally cooled to room temperature; the shale powder is prepared by crushing shale until the crushed shale passes through a 0.8 mm sieve and drying, and the water content of the material before aging is between 12 and 16 percent.

(1) grinding gypsum into powder, mixing the powder with basalt fibers with the length of 2-5 mm according to the mass ratio of 18:2.5, adding 35% of sodium silicate aqueous solution with the mass fraction of 0.45% into the mixture, continuously stirring for 20 minutes at the speed of 155 revolutions per minute, then adding 1.9 times of water by volume, quickly stirring at the speed of 550 revolutions per minute for 35 minutes, and standing the obtained mixed material for 18 hours at 112 ℃ and the humidity of 94%;

(2) and (2) taking out the material obtained in the step (1), stirring and dispersing, adding montmorillonite and silica aerogel with the mass fractions of 5.0% and 2.1% respectively, wherein the particle size of the silica aerogel is between 80 and 120 nanometers, continuing stirring for 28 minutes, standing for 4.5 hours, drying in an oven at 85 ℃ for 5 hours, then transferring to a muffle furnace, heating to 665 ℃, carrying out heat preservation and calcination for 75 minutes, naturally cooling to room temperature along with the furnace, and grinding to 155 meshes of sieve to obtain the pore-forming agent.

A test piece of a hollow brick having a size of 190 mm. times.100 mm. times.60 mm was produced according to the production method of example 1, and the thermal conductivity of the sintered hollow brick was measured by a heat flow meter type thermal conductivity meter, and the test procedure was carried out with reference to GB/T10295-2008, and the test piece had a thermal conductivity of 0.19W/m.k, a void ratio of 53% and a density of 0.80kg/dm 3.

Other properties: the mechanical properties of the samples are measured, the average level of 10 samples is taken, and the test standard is carried out by the method of GB13544-2000 and GB/T2542-92, and the results are obtained: the compressive strength reaches 25MPa, and the drying shrinkage rate is 4.8%.

Example 3

A preparation method of a heat-insulating hollow brick comprises the following steps: mixing the gangue after being sorted and removing impurities with the fly ash according to the mass ratio of 6:4, finely crushing the gangue and the fly ash by using a crusher until the gangue and the fly ash pass through a 1.0 mm sieve, adding water while stirring, adjusting the water content of a mud mass to be between 14 and 16 percent, then adding shale powder with the mass fraction of 11 percent of the mass of the mud mass, uniformly mixing and stirring, placing the mixture at 160 ℃ for heat treatment for 10 hours, further finely crushing the mixture until the shale powder passes through a 0.2 mm sieve, then placing the material into a stirring barrel, adding pore-forming agent with the mass fraction of 1.6 percent of the mass of the material, uniformly stirring and mixing, adding water, uniformly stirring, aging for 48 hours, pouring the mixture into a stirrer for stirring and mixing, then placing the mixture into a hydraulic extruder for extrusion molding, wherein the molding pressure is 2.5MPa, the extruded mixture is manually cut, placing the dried on a tray for 8 hours, maintaining the mixture at the air relative humidity of 85 percent and the temperature of 60 ℃, the flow rate of a drying medium is 3.0 m/s, the dried green brick is placed in an electric furnace preheated at 300 ℃ for heating and roasting, an intermittent heating mode is adopted, the temperature is raised to 600 ℃ at the heating rate of 3.0 ℃/min in the first stage, the temperature is kept for 50 min, the temperature is raised to 930 ℃ at the heating rate of 1.2 ℃/min in the second stage, the temperature is kept for calcining for 120 min, and then the green brick is naturally cooled to room temperature; the shale powder is prepared by crushing shale until the crushed shale passes through a 1.0 mm sieve and drying, and the water content of the material before aging is between 12 and 16 percent.

(1) grinding gypsum into powder, mixing the powder with basalt fibers with the length of 2-5 mm according to the mass ratio of 20:3, adding 40% of a sodium silicate aqueous solution with the mass fraction of 00.5% into the mixture, continuously stirring for 22 minutes at the speed of 160 revolutions per minute, then adding 2.0 times of volume of water, quickly stirring at the speed of 600 revolutions per minute for 40 minutes, and standing the obtained mixed material for 20 hours at the temperature of 115 ℃ and the humidity of 95%;

(2) and (2) taking out the material obtained in the step (1), stirring and dispersing, adding montmorillonite and silica aerogel with the mass fractions of 5.5% and 2.3% respectively, wherein the particle size of the silica aerogel is between 80 and 120 nanometers, continuing stirring for 30 minutes, standing for 5 hours, drying in an oven at 90 ℃ for 6 hours, transferring to a muffle furnace, heating to 680 ℃, carrying out heat preservation and calcination for 80 minutes, naturally cooling to room temperature along with the furnace, and grinding to a particle size of 160 meshes, thus obtaining the pore-forming agent.

A test piece of a hollow brick having a size of 190 mm. times.100 mm. times.60 mm was produced according to the production method of example 1, and the thermal conductivity of the sintered hollow brick was measured by a heat flow meter type thermal conductivity meter, and the test procedure was carried out with reference to GB/T10295-2008, and the test piece had a thermal conductivity of 0.21W/m.k, a void ratio of 50%, and a density of 0.82kg/dm 3.

Other properties: the mechanical properties of the samples are measured, the average level of 10 samples is taken, and the test standard is carried out by the method of GB13544-2000 and GB/T2542-92, and the results are obtained: the compressive strength reaches 23.0MPa, and the drying shrinkage rate is 5.0%.

In the control group, the pore-forming agent components and the amount of the pore-forming agent in the method for sintering the self-insulation brick by using mineralized refuse, sludge and construction waste are used in the CN201610460569.5 publication number, and the rest are kept unchanged instead of the pore-forming agent in the embodiment 2.

First, performance experiment

The sintered heat-insulating hollow brick is prepared by using the methods of the embodiment group and the comparison group, the influence of the usage amount of the pore-forming agent and the comparison group pore-forming agent on the compressive strength of the hollow brick is compared, the independent variables in the test are kept consistent, the effective average value is counted (the test design is carried out by using a statistical method before the test, then the test is carried out, the test data is recorded, the test result is obtained by analysis, the result is explained to the maximum extent by fully using a statistical tool in the process), and the result is shown in figure 1.

The hollow brick has the advantages that the firing speed is accelerated in the sintering process, a new phase is formed with the components of a green brick matrix, the strength of the hollow brick is improved, the drying shrinkage rate is reduced, cracks are not easy to generate in use, the thermal resistance of an air space is improved, the heat loss caused by heat conduction is reduced, the heat conductivity coefficient of the prepared heat-insulating sintered hollow brick is obviously reduced, the heat conductivity coefficient is as low as 0.19-0.21W/m.k, the porosity is 50-53%, the density is 0.80-0.82kg/dm3, the compressive strength is 21-25MPa, the drying shrinkage rate is 4.8-5.0%, the heat-insulating hollow brick has excellent heat-insulating and energy-saving properties and higher compressive strength, the heat-insulating properties of the hollow brick serving as a wall material are effectively improved, the energy-saving standard requirements are met, the energy consumption is saved, the production cost is reduced, the hollow brick has a wide application prospect, The research of the energy-saving self-insulation building material lays a foundation.

Claims

1. A preparation method of an air brick with excellent heat insulation performance is characterized by comprising the following steps:

(1) grinding gypsum into powder, mixing the powder with basalt fibers with the length of 2-5 mm according to the mass ratio of 17-20:2-3, adding 30-40% of sodium silicate aqueous solution into the mixture, continuously stirring for 18-22 minutes at the speed of 150-;

(2) taking out the material obtained in the step (1), stirring and dispersing, adding montmorillonite and silica aerogel with the mass fractions respectively accounting for 4.5-5.5% and 2.0-2.3%, continuing to stir for 25-30 minutes, standing for 4-5 hours, placing in an oven at 80-90 ℃ for drying for 4-6 hours, then transferring to a muffle furnace, heating to 650-680 ℃, carrying out heat preservation and calcination for 70-80 minutes, naturally cooling to room temperature along with the furnace, and grinding to pass through a 150-phase 160-mesh sieve to obtain the pore-forming agent;

(3) mixing the gangue after being sorted and removing impurities with the fly ash raw material according to the mass ratio of 5-6:3-4, finely crushing the gangue and the fly ash raw material by using a crusher until the gangue and the fly ash raw material pass through a 0.8-1.0 mm sieve, adding water while stirring, adjusting the water content of a mud mass to be 14-16%, then adding shale powder with the mass fraction of 7-11% of the mass of the mud mass, uniformly mixing and stirring the shale powder, performing heat treatment at the temperature of 130 ℃ and 160 ℃ for 8-10 hours, further finely crushing the gangue and the fly ash raw material until the gangue and the fly ash pass through the 0.1-0.2 mm sieve, then putting the materials into a stirring barrel, adding a pore-forming agent with the mass fraction of 1.4-1.6% of the mass of the materials, uniformly stirring and mixing the;

(4) pouring the aged material obtained in the step (3) into a stirrer to be stirred and mixed, then putting the mixture into a hydraulic extruder to be extruded and molded, wherein the molding pressure is 2.0-2.5MPa, after extrusion, manually cutting the mixture, placing the mixture on a tray to be dried for 6-8 hours, maintaining the mixture for 10-16 hours at the air relative humidity of 80-85% and the temperature of 55-60 ℃, then placing the mixture in an electric heating forced air drying box with the temperature of 135-145 ℃ for drying to constant weight, placing the dried brick blank in an electric furnace with the temperature of 280-300 ℃ for heating and roasting, adopting an intermittent heating mode, heating the temperature to 600 ℃ with the temperature rise speed of 580-50 ℃ at the first stage at the speed of 2.5-3.0 ℃ per minute, preserving the temperature for 40-50 minutes, heating the temperature to 930 ℃ with the temperature of 900-100-phase at the second stage at the speed of 1.0-1.2 ℃ per, and then naturally cooling to room temperature.

2. The method for preparing an air brick with excellent heat preservation performance according to claim 1, wherein the mass fraction of the sodium silicate aqueous solution in the step (1) is 0.4-0.5%.

3. The method for preparing an air brick with excellent thermal insulation performance according to claim 1, wherein the silica aerogel in the step (2) has a particle size of 80-120 nm.

4. The method for preparing an air brick with excellent heat preservation performance as claimed in claim 1, wherein the shale powder in step (3) is prepared by crushing shale to pass through a 0.6-1.0 mm sieve and drying, and the water content of the material before aging is 12-16%.

5. The method of claim 1, wherein the flow rate of the drying medium in the step (4) is 2.5 to 3.0 m/s.