CN113816759B - Heat-insulating refractory material prepared from hazardous waste and preparation method thereof - Google Patents

Abstract

The invention particularly relates to a thermal insulation refractory material prepared from hazardous waste and a preparation method thereof, which belongs to the technical field of comprehensive utilization of industrial hazardous waste. The method includes: performing the first water washing pretreatment on the secondary aluminum ash to obtain the pretreated secondary aluminum ash ; carry out the second washing pretreatment of the regenerated aluminum dedusting ash to obtain the pretreated regenerated aluminum dedusting ash; mix the pretreated secondary aluminum ash, the pretreated regenerated aluminum dedusting ash and silicon-rich solid waste, and then carry out ball milling to obtain a mixed raw meal; adding water and stirring the mixed raw meal to obtain a wet raw meal, foaming and molding the wet raw meal, and then drying to obtain a green body; sintering the green body to obtain Insulation and refractory materials; synergistic and complementary use of aluminum, carbon, silicon and other element resources in secondary aluminum ash and dedusting ash to convert secondary aluminum ash and dedusting ash into thermal insulation and refractory materials, while solving the problem of hazardous waste in the aluminum industry, realizing secondary High-value utilization of aluminum ash and dust removal ash.

Description

A thermal insulation refractory material prepared from hazardous waste and its preparation method

technical field

The invention belongs to the technical field of comprehensive utilization of industrial hazardous waste, and in particular relates to a thermal insulation refractory material prepared from hazardous waste and a preparation method thereof.

Background technique

Aluminum ash is a hazardous waste generated during electrolytic aluminum, aluminum processing and secondary aluminum production. The annual output of aluminum ash in my country exceeds 2 million tons. At present, the technology of aluminum ash recycling metal aluminum is mature, and the recovery rate is above 70%. Secondary aluminum ash is the fine ash left after aluminum ash is recycled. According to the "National Hazardous Waste List" (2021 Edition), secondary aluminum ash belongs to HW48 non-ferrous metal mining and smelting waste, and the waste codes of secondary aluminum ash are 321-024-48 and 321-026-48, which are produced by electrolytic aluminum respectively. Secondary aluminum ash and secondary aluminum ash produced by secondary aluminum and aluminum processing. In addition, aluminum ash heat recovery aluminum, aluminum smelting and recycled aluminum process dust are also classified as hazardous waste, and their waste code is 321-034-48. Secondary aluminum ash contains soluble salts such as alumina, aluminum nitride, metallic aluminum, magnesium aluminum spinel, chloride salts, fluoride salts, and oxides such as Ca, Si, and Fe. Due to the low aluminum content and complex impurity components of the secondary aluminum ash metal, comprehensive utilization is difficult. In addition to aluminum oxide, silicon oxide, and aluminum nitride, the dust generated during the recycling process of waste aluminum also contains a large amount of carbon components such as hydrocarbons and carbon ash. With the limit value of electrolytic aluminum production, the secondary aluminum industry has ushered in a stage of rapid development. With the increase of secondary aluminum production capacity, the amount of dust removal in the secondary aluminum smelting process will also increase. How to efficiently dispose and utilize hazardous waste such as secondary aluminum ash and dust ash generated in the aluminum industry is a key issue restricting the green development of the aluminum industry at this stage. In fact, secondary aluminum ash and dedusting ash are also a kind of aluminum-rich resources. If we make good use of their resource properties, transform them into high-value products, and realize the resource utilization of hazardous waste, it will play an important role in the sustainable development of the industry. .

Lightweight refractory materials are also called thermal insulation refractory materials or thermal insulation refractory materials. They are essential energy-saving materials for high-temperature kilns and thermal equipment. refractory materials. Generally, high-alumina heat-insulating refractory materials are made of bauxite clinker, combined with clay as raw materials, mixed with binders and sawdust and other auxiliary materials and sintered. With the shortage of bauxite resources, the source of raw materials is limited, and the production cost Gradually increase, and the secondary aluminum ash and dedusting ash contain a large amount of alumina resources, and it has a significant cost advantage to prepare refractory materials from it.

Chinese invention patent application CN109678556A discloses a method of using aluminum ash to prepare lightweight high-alumina insulation bricks, adding pore-forming agents, sintering aids, etc. to the pretreated aluminum ash to prepare wet mud, extruding into dense bricks and firing High alumina insulation brick. Chinese invention patent application CN109111234A discloses the formula and preparation method of reprocessing waste aluminum ash to make homogeneous refractory raw materials. Waste aluminum ash, combined powder and dry adhesive are processed by mixing materials, pressing and firing in a certain proportion. It is prepared as a homogeneous refractory raw material, wherein the bonding powder is alumina and silicon oxide, and the dry binder is obtained by drying wood pulp waste liquid. Chinese invention patent application CN107151148A discloses a cordierite thermal insulation refractory ball and a preparation method thereof, wherein cordierite, aluminum ash, talcum powder, sawdust, and adhesive are used as main raw materials, and the amount of aluminum ash is 15-20%. Chinese invention patent application CN111170750A discloses a method for manufacturing refractory materials through harmless treatment of secondary aluminum ash. The secondary aluminum ash is ground and calcined and then arc smelted into aluminum-magnesium refractory materials or corundum by adding additives. refractory material. Chinese invention patent application CN112110738A discloses a method for preparing high-alumina refractory materials from aluminum ash. After the aluminum ash is washed, filtered, and dried, it is pickled, and then the purified slag is formed and sintered to prepare high-alumina refractory materials.

The above technologies all use secondary aluminum ashes as raw materials to prepare refractory materials, and all of them need to add sintering aids and ignition loss. The auxiliary materials used are more complicated and the preparation cost is higher.

Contents of the invention

The purpose of this application is to provide a thermal insulation refractory material prepared from hazardous waste and its preparation method to solve the technical problem that the utilization of secondary aluminum ash in the existing technology must rely on the addition of sintering aids and burnt matter.

The embodiment of the present invention provides a method for preparing thermal insulation refractory materials prepared from hazardous waste, the method comprising:

The secondary aluminum ash is subjected to the first washing pretreatment to obtain the pretreated secondary aluminum ash;

Carrying out the second water washing pretreatment to the regenerated aluminum dedusting ash to obtain the pretreated regenerated aluminum dedusting ash;

mixing the pretreated secondary aluminum ash, the pretreated regenerated aluminum dust and silicon-rich solid waste, and then ball milling to obtain a mixed raw meal;

adding water and stirring the mixed raw meal to obtain wet raw meal;

foam molding the wet raw material, and then drying to obtain a green body;

Sintering the green body by increasing the temperature step by step to obtain a heat-insulating refractory material;

In the stage-by-stage temperature-raising sintering, the heating rate of each stage varies with the sintering temperature of each stage.

Optionally, the variation of the heating rate of each section with the sintering temperature of each section specifically includes:

When the sintering temperature is <300°C, the heating rate of the sintering is 2.5°C/min-3.5°C/min;

When 300°C≤sintering temperature<600°C, the heating rate of the sintering is 4.5°C/min-5.5°C/min;

When 600°C≤sintering temperature<1000°C, the heating rate of the sintering is 3.5°C/min-4.5°C/min;

When 1000°C≤sintering temperature<final sintering temperature, the heating rate of the sintering is 2.5°C/min-3.5°C/min, and the final sintering temperature is 1200°C-1350°C.

Optionally, the water quality of the first water washing pretreatment is 2.5-3.5 times the quality of the secondary aluminum ash, the washing time of the first water washing pretreatment is 8min-12min, and the pretreatment secondary aluminum The moisture content of the ash is ≤ 2%; the water quality of the second water washing pretreatment is 2.5-3.5 times the quality of the regenerated aluminum dedusting ash, and the washing time of the second water washing pretreatment is 8min-12min. The moisture content of recycled aluminum dedusting ash is ≤2%.

Optionally, the raw materials of the mixed raw meal include by mass: 60%-80% of pretreated secondary aluminum ash, 10%-35% of pretreated recycled aluminum dust and 5%-10% of silicon-rich solid waste .

Optionally, the silicon-rich solid waste includes at least one of fly ash, silica fume and coal gangue.

Optionally, the particle size of the mixed raw meal is 160 mesh sieve.

Optionally, in the stirring with adding water, the mass of water added is 30%-60% of the mass of the mixed raw meal.

Optionally, the foam molding time is 25 minutes to 35 minutes.

Optionally, the moisture content of the green body is ≤2%.

Based on the same inventive concept, the embodiment of the present invention also provides a thermal insulation refractory material prepared from hazardous waste, and the thermal insulation refractory material is prepared by the above-mentioned preparation method of thermal insulation refractory material prepared from hazardous waste.

One or more technical solutions in the embodiments of the present invention have at least the following technical effects or advantages:

The preparation method of the thermal insulation refractory material prepared from hazardous waste provided by the embodiment of the present invention, the method includes: performing the first water washing pretreatment on the secondary aluminum ash to obtain the pretreated secondary aluminum ash; performing the second Two washing pretreatments to obtain pretreated regenerated aluminum ash; mixing the pretreated secondary aluminum ash, the pretreated regenerated aluminum ash and silicon-rich solid waste, and then ball milling to obtain mixed raw meal; The mixed raw meal is stirred with water to obtain a wet raw meal. The wet raw meal is foamed and molded, and then dried to obtain a green body; the green body is sintered by increasing the temperature step by step to obtain a thermal insulation refractory material; In the stage-by-stage heating sintering, the heating rate of each stage changes with the sintering temperature of each stage; based on the complementary characteristics of raw materials, the stage reaction pore formation at different temperatures in the material preparation process is realized, without additional foaming agent and pore-forming agent, overcoming The current technical prejudice that the use of secondary aluminum ash needs to add sintering aids and ignition loss.

Based on the complementary characteristics of raw materials, the stage reaction pore formation at different temperatures in the material preparation process is realized. The principle of pore formation in the preparation process stage is as follows: (1) During the green body preparation process, the metal aluminum and partial nitriding in the secondary aluminum ash and dust removal ash are used Aluminum hydrolysis releases hydrogen and ammonia to generate pores, that is, hydrolysis foaming creates pores; (2) During the sintering process, the carbon component contained in the dust will burn out at 300-600°C to produce carbon dioxide pores, that is, medium temperature burnout Pore formation; (3) Above 600°C, the residual aluminum nitride and aluminum carbide in the secondary aluminum ash will decompose and release nitrogen and carbon dioxide to form pores, that is, pyrolysis pore formation. The present invention is based on the three pore-forming processes of raw material hydrolysis and foaming, medium-temperature burning loss and high-temperature decomposition pore-making, and realizes more diverse and richer pores of the heat-resisting refractory material. At the same time, since the secondary aluminum ash contains a small amount of low-melting point phases such as calcium fluoride, it will combine with alumina and silicon oxide to form a liquid-phase grain boundary barrier film during high-temperature sintering, thereby sealing the generated gas in a local area , forming a large number of closed pores, which increases the stability of the pores, thereby ensuring the thermal insulation performance of the material.

The above description is only an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention, it can be implemented according to the contents of the description, and in order to make the above and other purposes, features and advantages of the present invention more obvious and understandable , the specific embodiments of the present invention are enumerated below.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings that need to be used in the description of the embodiments. Obviously, the drawings in the following description are some embodiments of the present invention. For those skilled in the art, other drawings can also be obtained based on these drawings without creative effort.

Fig. 1 is the flowchart of the method provided by the embodiment of the present invention;

Fig. 2 is a process block diagram provided by an embodiment of the present invention.

Detailed ways

The present invention will be described in detail below in conjunction with specific embodiments and examples, and the advantages and various effects of the present invention will be presented more clearly. Those skilled in the art should understand that these specific implementations and examples are used to illustrate the present invention, not to limit the present invention.

Throughout the specification, unless otherwise specified, terms used herein should be understood as commonly used in the art. Therefore, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. In case of conflict, this specification shall take precedence.

Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or prepared by existing methods.

The technical solution of the embodiment of the present application is to solve the above-mentioned technical problems, and the general idea is as follows:

In order to overcome the problems of complex raw materials and high processing costs in the process of preparing refractory materials from secondary aluminum ash in the prior art, the present invention provides a method for preparing thermal insulation refractory materials using secondary aluminum ash and recycled aluminum dust removal ash. Solving the problem of secondary aluminum ash and dust removal ash produced by secondary aluminum smelting, synergistic and complementary use of aluminum, carbon, silicon and other element resources in secondary aluminum ash and dust removal ash to convert secondary aluminum ash and dust removal ash into thermal insulation refractory materials, While solving the problem of hazardous waste in the aluminum industry, realize the high-value utilization of secondary aluminum ash and dust removal ash.

According to a typical implementation of the present invention, a method for preparing a thermal insulation refractory material prepared from hazardous waste is provided, the method comprising:

S1. Carrying out the first washing pretreatment of the secondary aluminum ash to obtain the pretreated secondary aluminum ash;

As an optional implementation, the water quality of the first water washing pretreatment is 2.5-3.5 times the quality of the secondary aluminum ash, the washing time of the first water washing pretreatment is 8min-12min, the The moisture content of the pretreated secondary aluminum ash is ≤2%.

S2. Perform the second washing pretreatment on the regenerated aluminum dedusting ash to obtain the pretreated regenerated aluminum dedusting ash;

It should be noted that the source of recycled aluminum dedusting can be the dedusting ash collected by the bag filter device during the recycling and smelting of scrap aluminum, or the dedusting ash from other sources with similar composition.

As an optional implementation, the water quality of the second water washing pretreatment is 2.5-3.5 times the quality of the regenerated aluminum dedusting ash, the washing time of the second water washing pretreatment is 8min-12min, the The moisture content of the pretreated recycled aluminum dust removal ash is ≤2%.

S3. Mix the pretreated secondary aluminum ash, the pretreated regenerated aluminum dust and silicon-rich solid waste, and then perform ball milling to obtain a mixed raw meal;

Specifically, the pretreated secondary aluminum ash and recycled aluminum dust are weighed and mixed with silicon-rich solid waste according to the mass ratio, and then added to a ball mill for ball milling until all are sieved to 160 mesh to obtain mixed raw meal.

As an optional implementation, the raw materials of mixed raw meal include by mass: 60%-80% of pretreated secondary aluminum ash, 10%-35% of pretreated recycled aluminum dust and 5% of silicon-rich solid waste -10%.

Controlling the mass fraction of the pretreated secondary aluminum ash to 60%-80% is beneficial to control the alumina content in the thermal insulation refractory material. If the fraction is too large, the corundum phase in the material will increase, resulting in excessive volume density of the product. As a result, the compressive strength of the product is reduced and the fire resistance performance is deteriorated.

Controlling the mass fraction of pretreated recycled aluminum dust to 10%-35% is beneficial to reasonably control the bulk density of thermal insulation refractory materials. If the fraction is too large, it will cause too many pores in the product, the volume density is too small, and the compressive strength is reduced. , too small will lead to too few holes in the thermal insulation refractory material, small porosity, and poor thermal insulation performance.

Controlling the mass fraction of silicon-rich solid waste at 5%-10% is conducive to the formation of stable mullite mineral phase by the silica in the silicon-rich solid waste and the alumina in the pretreated secondary aluminum ash and recycled aluminum dust removal ash , so that its content is controlled within a reasonable range to improve the compressive strength and fire resistance of the product. If the value of this score is too large, the bulk density of the material will be too large, the porosity is small, and the thermal insulation performance is poor. The compressive strength is reduced.

As an optional embodiment, the silicon-rich solid waste may be selected from at least one of fly ash, silica fume and coal gangue.

As an optional embodiment, the particle size of the mixed raw meal is to pass through a 160-mesh sieve.

S4. Stir the mixed raw meal with water to obtain wet raw meal;

As an optional implementation, in adding water and stirring, the mass of water added is 30%-60% of the mass of the mixed raw meal.

Controlling the addition of water to 30%-60% of the mass of the mixed raw meal is beneficial to the mixing and molding of the mixed raw meal. If the ratio is too large, the raw meal will have too much fluidity, high moisture content, and difficult operation. After drying, the mechanical strength is poor, and the adverse effect of too small is that it is difficult to mix the raw materials evenly, and the molding operation is difficult.

S5. Foaming and molding the wet raw material, and then drying to obtain a green body;

Specifically, the mixed raw material is mixed with water and evenly put into the mold, and the green body of the wet material is stably foamed in the mold for 30 minutes, and then put into the dryer for drying until the moisture content is ≤ 2%, and then demolded , to get the green body.

S6. Sintering the green body to obtain a thermal insulation refractory material.

Specifically, the green body is put into a high-temperature kiln for sintering, and after being fired, it is naturally cooled to room temperature, and then the fired product is cut and processed to obtain a lightweight thermal insulation refractory material.

As an optional implementation, sintering specifically includes:

When the sintering temperature is <300°C, the heating rate of the sintering is 2.5°C/min-3.5°C/min;

When 300°C≤sintering temperature<600°C, the heating rate of the sintering is 4.5°C/min-5.5°C/min;

When 600°C≤sintering temperature<1000°C, the heating rate of the sintering is 3.5°C/min-4.5°C/min;

When 1000°C≤sintering temperature<final sintering temperature, the heating rate of the sintering is 2.5°C/min-3.5°C/min, and the final sintering temperature is 1200°C-1350°C.

The reason for changing the sintering heating rate at different sintering temperatures is: based on the different sintering reaction gas generation pore-forming principles of materials at different temperature stages, by controlling the heating rate at different sintering temperature sections to ensure that the gas released during different stages of pore-forming process is more uniform and stable, Avoid material deformation and cracking, and at the same time ensure that the mineral phase transformation in the product is more sufficient and the material is more homogeneous.

The raw materials used above are all industrial solid wastes, of which the raw materials are mainly secondary aluminum ash, recycled aluminum dedusting ash and silicon-rich solid waste, among which the secondary aluminum ash and dedusting ash are pretreated to elute soluble chloride salts and fluoride salt, the main components of secondary aluminum ash after pretreatment are Al ₂ O ₃ , AlN, MgO, SiO ₂ , CaF ₂ and elemental Al, etc. The main components of dust removal ash after pretreatment are Al ₂ O ₃ , SiO ₂ , carbon Hydrogen compound, carbon particle ash and elemental Al etc., because the silicon dioxide content in the secondary aluminum ash of pretreatment is on the low side, this method is by additionally adding a small amount of silicon-rich solid waste (fly ash, silica fume and coal gangue) , to complement the lack of silica in the ingredients, to regulate the content of the mullite phase in the product, and to improve the mechanical strength and fire resistance of the product.

This method does not need to add additional foaming agent and pore-forming agent. Based on the complementary characteristics of the raw materials, the stage reaction pore formation at different temperatures in the material preparation process is realized. The principle of pore formation in the preparation process stage is as follows: (1) During the green body preparation process, use Secondary aluminum ash and dedusting ash contain metal aluminum and part of aluminum nitride hydrolyzed to release hydrogen and ammonia gas to form pores, that is, hydrolysis foaming to form pores; -600°C will burn out and produce carbon dioxide pores, that is, medium temperature burnout and create pores; (3) above 600°C, the residual aluminum nitride and aluminum carbide in the secondary aluminum ash will decompose and release nitrogen and carbon dioxide to generate pores, that is, high temperature Break down holes. The present invention is based on the three pore-forming processes of raw material hydrolysis and foaming, medium-temperature burning loss and high-temperature decomposition pore-making, and realizes more diverse and richer pores of the heat-resisting refractory material. At the same time, since the secondary aluminum ash contains a small amount of low-melting point phases such as calcium fluoride, it will combine with alumina and silicon oxide to form a liquid-phase grain boundary barrier film during high-temperature sintering, thereby sealing the generated gas in a local area , forming a large number of closed pores, which also increases the stability of the pores, thus ensuring the thermal insulation performance of the material.

According to another typical embodiment of the present invention, a thermal insulation refractory material prepared from hazardous waste is provided, and the thermal insulation refractory material is prepared by the method for preparing thermal insulation refractory material prepared from hazardous waste as provided above.

The thermal insulation refractory material prepared from hazardous waste and the preparation method thereof of the present application will be described in detail below in combination with examples, comparative examples and experimental data.

Example 1

A method for preparing thermal insulation refractory materials prepared from hazardous waste, the method comprising:

Add secondary aluminum ash and regenerated aluminum dedusting ash to 3 times of water respectively, stir and wash for 10 minutes, filter after washing, and dry the filter cake until the water content is ≤2%; according to the mass ratio of 70%, 22% and 8% Weigh the pretreated secondary aluminum ash, pretreated regenerated aluminum dust and fly ash, and add them to a ball mill for mixing and ball milling until all are sieved to 160 mesh to obtain mixed raw meal; add water according to 40% of the mass of mixed raw meal, and mix with Stir the raw material to make a wet material, put the wet material into the mold for stable foaming for 30 minutes, then put it into the dryer for drying until the moisture content is ≤2%, and demould to obtain the green body; put the green body into Sintering is carried out in a high-temperature kiln, and the sintering program is as follows: the heating rate is 3°C/min in the stage of room temperature-300°C, the heating rate in the stage of 300-600°C is 5°C/min, the heating rate in the stage of 600-1000°C is 4°C/min, and the heating rate in the stage of 1000°C- The heating rate in the 1280°C stage is 3°C/min, and the temperature is kept at 1280°C for 40 minutes. After the heat preservation, it is cooled with the furnace, and the fired products are cut and processed to obtain light-weight heat-resisting refractory materials.

Example 2

A method for preparing thermal insulation refractory materials prepared from hazardous waste, the method comprising:

Add secondary aluminum ash and regenerated aluminum dedusting ash to 3 times of water respectively, stir and wash for 10 minutes, filter after washing, and dry the filter cake until the moisture content is ≤2%; according to the mass ratio of 80%, 10% and 10% Weigh pretreated secondary aluminum ash, pretreated recycled aluminum dust and fly ash, and add them to a ball mill for mixing and ball milling until all are sieved to 160 mesh to obtain mixed raw meal; add water according to 30% of the mass of mixed raw meal, and mix with Stir the raw material to make a wet material, put the wet material into the mold for stable foaming for 30 minutes, then put it into the dryer for drying until the moisture content is ≤2%, and demould to obtain the green body; put the green body into Sintering is carried out in a high-temperature kiln, and the sintering program is as follows: the heating rate is 3°C/min in the stage of room temperature-300°C, the heating rate in the stage of 300-600°C is 5°C/min, the heating rate in the stage of 600-1000°C is 4°C/min, and the heating rate in the stage of 1000°C- The heating rate in the 1250°C stage is 3°C/min, and the temperature is maintained at 1250°C for 60 minutes. After the heat preservation, it is cooled with the furnace, and the fired products are cut and processed to obtain light-weight heat-resisting refractory materials.

Example 3

A method for preparing thermal insulation refractory materials prepared from hazardous waste, the method comprising:

Add secondary aluminum ash and regenerated aluminum dedusting ash to 3 times of water respectively, stir and wash for 10 minutes, filter after washing, and dry the filter cake until the water content is ≤2%; according to the mass ratio of 60%, 35% and 5% Weigh the pretreated secondary aluminum ash, pretreated regenerated aluminum dust and fly ash, and add them to a ball mill for mixing and ball milling until all are sieved to 160 mesh to obtain mixed raw meal; add water according to 60% of the mass of mixed raw meal, and mix with Stir the raw material to make a wet material, put the wet material into the mold for stable foaming for 30 minutes, then put it into the dryer for drying until the moisture content is ≤2%, and demould to obtain the green body; put the green body into Sintering is carried out in a high-temperature kiln, and the sintering program is as follows: the heating rate is 3°C/min in the stage of room temperature-300°C, the heating rate in the stage of 300-600°C is 5°C/min, the heating rate in the stage of 600-1000°C is 4°C/min, and the heating rate in the stage of 1000°C- The heating rate in the 1300°C stage is 3°C/min, and the temperature is kept at 1300°C for 30 minutes. After the heat preservation, it is cooled with the furnace, and the fired products are cut and processed to obtain light-weight heat-resisting refractory materials.

Example 4

A method for preparing thermal insulation refractory materials prepared from hazardous waste, the method comprising:

Add secondary aluminum ash and regenerated aluminum dedusting ash to 3 times of water respectively, stir and wash for 10 minutes, filter after washing, and dry the filter cake until the water content is ≤ 2%; according to the mass ratio of 66%, 27%, 4% , 5% by weighing pretreated secondary aluminum ash, pretreated regenerated aluminum dust, fly ash and coal gangue, and adding them to a ball mill for mixing and ball milling until all are sieved to 160 mesh to obtain mixed raw meal; according to the quality of mixed raw meal Add water to 52%, stir with mixed raw materials to make wet material, put the wet material into the mold for stable foaming for 30 minutes, then put it into the dryer for drying, dry until the moisture content is ≤ 2%, demould to get the green body ;Put the green body into a high-temperature kiln for sintering. The sintering program is: the heating rate of room temperature-300°C is 3°C/min, the heating rate of 300-600°C is 5°C/min, and the heating rate of 600-1000°C is 4°C. /min, 1000°C-1300°C stage heating rate is 3°C/min, 1200°C heat preservation for 50min, after heat preservation, it is cooled with the furnace, and the fired products are cut and processed to obtain light heat preservation refractory materials.

Example 5

A method for preparing thermal insulation refractory materials prepared from hazardous waste, the method comprising:

Add secondary aluminum ash and regenerated aluminum dedusting ash to 3 times of water respectively, stir and wash for 10 minutes, filter after washing, and dry the filter cake until the water content is ≤2%; according to the mass ratio of 72%, 20%, and 3% , 5% by weighing pretreated secondary aluminum ash, pretreated regenerated aluminum dust, coal gangue and silica fume, and adding them to a ball mill for mixing and ball milling until all are sieved to 160 meshes to obtain mixed raw meal; according to the quality of mixed raw meal 38 % Add water, stir with mixed raw materials to make wet material, put the wet material into the mold for stable foaming for 30 minutes, then put it into the dryer for drying, dry until the moisture content is ≤ 2%, and demould to obtain the green body; Put the green body into a high-temperature kiln for sintering. The sintering program is: the heating rate of room temperature-300°C is 3°C/min, the heating rate of 300-600°C is 5°C/min, and the heating rate of 600-1000°C is 4°C/min. Min, 1000°C-1330°C stage heating rate is 3°C/min, 1330°C heat preservation for 35min, after heat preservation, cool with the furnace, and cut the fired products to obtain light heat preservation refractory materials.

Embodiment 6:

A method for preparing thermal insulation refractory materials prepared from hazardous waste, the method comprising:

Add the secondary aluminum ash and the regenerated aluminum dedusting ash to 3 times of water respectively, stir and wash for 10 minutes, filter after washing, and dry the filter cake until the moisture content is ≤2%; according to the mass ratio of 78%, 12%, and 4% , 6% by weighing pretreated secondary aluminum ash, pretreated regenerated aluminum dust, fly ash and silica fume, and adding them to a ball mill for mixing and ball milling until all are sieved to 160 mesh to obtain mixed raw meal; according to the quality of mixed raw meal Add 35% water, stir with mixed raw materials to make wet material, put the wet material into the mold for stable foaming for 30 minutes, then put it into the dryer for drying until the moisture content is ≤ 2%, demould to get the green body ;Put the green body into a high-temperature kiln for sintering. The sintering program is: the heating rate of room temperature-300°C is 3°C/min, the heating rate of 300-600°C is 5°C/min, and the heating rate of 600-1000°C is 4°C. /min, 1000°C-1350°C stage heating rate is 3°C/min, 1350°C heat preservation for 38min, after heat preservation, cool with the furnace, and cut the fired products to obtain light heat preservation refractory materials.

Example 7

A method for preparing thermal insulation refractory materials prepared from hazardous waste, the method comprising:

Add secondary aluminum ash and regenerated aluminum dedusting ash respectively with 3 times of water, stir and wash for 10 minutes, filter after washing, and dry the filter cake until the water content is ≤ 2%; according to the mass ratio of 75%, 16%, 5% , 4% by weighing pretreated secondary aluminum ash, pretreated regenerated aluminum dust, fly ash and coal gangue, and adding them to a ball mill for mixed ball milling until all sieved to 160 mesh to obtain mixed raw meal; according to the quality of mixed raw meal Add water at 42%, stir with mixed raw materials to make wet material, put the wet material into the mold for stable foaming for 30 minutes, then put it into the dryer for drying until the moisture content is ≤ 2%, demould to get the green body ;Put the green body into a high-temperature kiln for sintering. The sintering program is: the heating rate of room temperature-300°C is 3°C/min, the heating rate of 300-600°C is 5°C/min, and the heating rate of 600-1000°C is 4°C. /min, 1000°C-1220°C stage heating rate is 3°C/min, 1220°C heat preservation 55min, after heat preservation, cool with the furnace, and cut the fired products to obtain light heat preservation refractory materials.

Example 8

A method for preparing thermal insulation refractory materials prepared from hazardous waste, the method comprising:

Add the secondary aluminum ash and the regenerated aluminum dedusting ash to 3 times of water respectively, stir and wash for 10 minutes, filter after washing, and dry the filter cake until the moisture content is ≤2%; according to the mass ratio of 63%, 30%, and 3% , 4% by weighing pretreated secondary aluminum ash, pretreated regenerated aluminum dust, fly ash and silica fume, and adding them to a ball mill for mixing and ball milling until all are sieved to 160 mesh to obtain mixed raw meal; according to the quality of mixed raw meal Add 55% water, stir with mixed raw material to make wet material, put the wet material into the mold for stable foaming for 30 minutes, then put it into the dryer for drying until the moisture content is ≤ 2%, demould to get the green body ;Put the green body into a high-temperature kiln for sintering. The sintering program is: the heating rate of room temperature-300°C is 3°C/min, the heating rate of 300-600°C is 5°C/min, and the heating rate of 600-1000°C is 4°C. /min, 1000°C-1270°C stage heating rate is 3°C/min, 1270°C heat preservation for 43 minutes, after heat preservation, cool with the furnace, and cut the fired products to obtain light heat preservation refractory materials.

Example 9

A method for preparing thermal insulation refractory materials prepared from hazardous waste, the method comprising:

Add secondary aluminum ash and regenerated aluminum dedusting ash respectively with 3 times of water to stir and wash for 10 minutes, filter after washing, and dry the filter cake until the moisture content is ≤2%; according to the mass ratio of 74%, 21%, and 2% , 3% by weighing pretreated secondary aluminum ash, pretreated regenerated aluminum dust, coal gangue and silica fume, and adding them to a ball mill for mixing and ball milling until all are sieved to 160 meshes to obtain mixed raw meal; % Add water, stir with mixed raw materials to make wet material, put the wet material into the mold for stable foaming for 30 minutes, then put it into the dryer for drying, dry until the moisture content is ≤ 2%, and demould to obtain the green body; Put the green body into a high-temperature kiln for sintering. The sintering program is: the heating rate of room temperature-300°C is 3°C/min, the heating rate of 300-600°C is 5°C/min, and the heating rate of 600-1000°C is 4°C/min. Min, 1000°C-1310°C stage heating rate is 3°C/min, 1310°C heat preservation for 48min, after heat preservation, it is cooled with the furnace, and the fired products are cut and processed to obtain light heat preservation refractory materials.

Comparative example 1

A method for preparing thermal insulation refractory materials prepared from hazardous waste, the method comprising:

Add 3 times of water to the secondary aluminum ash for stirring and washing for 10 minutes, filter after washing, and dry the filter cake until the moisture content is ≤2%; weigh the pretreated secondary aluminum ash and add it to a ball mill for mixing and ball milling until all Sieve through 160 meshes to obtain the mixed raw meal; add water according to 40% of the mass of the mixed raw meal, stir with the mixed raw meal to make a wet material, put the wet material into a mold for stable foaming for 30 minutes, and then put it in a dryer for drying Drying, drying to a moisture content of ≤2%, demoulding to obtain a green body; putting the green body into a high-temperature kiln for sintering, the sintering procedure is: the temperature rise rate is 3°C/min in the stage of room temperature -300°C, and the stage of 300-600°C The heating rate is 5°C/min, the heating rate is 4°C/min in the stage of 600-1000°C, the heating rate in the stage of 1000°C-1310°C is 3°C/min, and the temperature is kept at 1280°C for 40 minutes. Cutting and processing to obtain lightweight thermal insulation refractory materials.

Comparative example 2

A method for preparing thermal insulation refractory materials prepared from hazardous waste, the method comprising:

Add 3 times of water to the secondary aluminum ash for stirring and washing, the washing time is 10min, filter after washing, and dry the filter cake until the moisture content is ≤2%; weigh the pretreated secondary aluminum ash and Fly ash is added to a ball mill for mixing and ball milling until all sieved to 160 mesh to obtain mixed raw meal; add water according to 40% of the mass of mixed raw meal, stir with mixed raw meal to make wet material, and put the wet material into a mold for stabilization Foaming for 30 minutes, then drying in a dryer until the moisture content is ≤ 2%, demoulding to obtain a green body; putting the green body into a high-temperature kiln for sintering, the sintering procedure is: room temperature - 300°C stage The heating rate is 3°C/min, the heating rate of 300-600°C is 5°C/min, the heating rate of 600-1000°C is 4°C/min, the heating rate of 1000°C-1310°C is 3°C/min, and the temperature is kept at 1280°C for 40 minutes. After heat preservation, it is cooled with the furnace, and the fired products are cut and processed to obtain light heat preservation refractory materials.

Comparative example 3

A method for preparing thermal insulation refractory materials prepared from hazardous waste, the method comprising:

Add secondary aluminum ash and regenerated aluminum dedusting ash respectively with 3 times of water to carry out stirring and washing for 10 minutes, filter after washing, and dry the filter cake until the moisture content is ≤2%; Process secondary aluminum ash and pre-treated regenerated aluminum dedusting ash, add them to a ball mill for mixing and ball milling until all are sieved to 160 mesh to obtain mixed raw meal; add water according to 40% of the mass of mixed raw meal, and stir with mixed raw meal to make wet meal , put the wet material into the mold for stable foaming for 30 minutes, then put it into the dryer for drying until the moisture content is ≤2%, and demould to obtain the green body; put the green body into the high-temperature kiln for sintering, The sintering program is: the heating rate of room temperature-300°C is 3°C/min; the heating rate of 300-600°C is 5°C/min; the heating rate of 600-1000°C is 4°C/min; ℃/min, 1280 ℃ for 40 minutes, after the heat preservation, it is cooled with the furnace, and the fired products are cut and processed to obtain light-weight heat-resisting refractory materials.

Experimental example

The thermal insulation refractory material that embodiment 1-9 and comparative example 1-3 are made detects, and the result is as shown in the table below:

It can be seen from the above table that the thermal insulation refractory material prepared by the method provided by the embodiment of the present invention has a volume density of 0.52-0.96g/cm ³ , and the properties of products with different volume densities are in line with the "High Alumina Lightweight Heat Insulation Refractory bricks" (GB/T3995-2014) (LG135-0.6L, LG135-0.7L, LG140-0.8L, LG140-1.0) standard requirements. In comparative example 1 and comparative example 2, the bulk density of the test blocks prepared by using single secondary aluminum ash and using secondary aluminum ash and silicon-rich solid waste all exceeded 1.1g/cm ³ , and the thermal conductivity did not meet the standard requirements . In comparative example 3, although the thermal insulation refractory material prepared by secondary aluminum ash and recycled aluminum dust removal ash has a low volume density, its normal temperature compressive strength is poor, which does not meet the standards and use requirements.

In summary, the lightweight thermal insulation refractory material prepared by the formula of the present invention has the characteristics of low bulk density, high apparent porosity, high compressive strength at room temperature, and low thermal conductivity.

One or more technical solutions in the embodiments of the present invention also have at least the following technical effects or advantages:

(1) The method provided by the embodiment of the present invention uses pretreated secondary aluminum ash, recycled aluminum dust and silicon-rich solid waste as raw materials to prepare thermal insulation refractory materials, fully utilizes the complementary advantages of elements, greatly reduces raw material costs, and also Effectively solved the problem of solid hazardous waste disposal and utilization in the aluminum industry;

(2) The method provided by the embodiment of the present invention does not need to add additional foaming agent and pore forming agent. Based on the characteristics of the raw material itself, it realizes the multi-stage pore forming in the preparation process, improves the porosity and pore stability of the product, and reduces the material density. bulk density;

(3) The thermal insulation refractory material prepared by the method provided in the embodiment of the present invention has excellent properties such as low bulk density, high apparent porosity, high normal temperature compressive strength, and low thermal conductivity, and the product can be widely used in the field of thermal insulation of industrial kilns ;

(4) The method provided by the embodiment of the present invention overcomes the problems of complex raw materials and high processing costs in the process of preparing refractories from secondary aluminum ash in the prior art, and simultaneously solves the problem of secondary aluminum ash and dust removal ash produced by secondary aluminum smelting, Synergetic and complementary use of aluminum, carbon, silicon and other elemental resources in secondary aluminum ash and dedusting ash, transforming secondary aluminum ash and dedusting ash into thermal insulation and refractory materials, while solving the problem of hazardous waste in the aluminum industry, realizing secondary aluminum ash and dedusting High value utilization of ash.

Finally, it should also be noted that the term "comprises", "comprises" or any other variation thereof is intended to cover a non-exclusive inclusion such that a process, method, article or apparatus comprising a set of elements includes not only those elements, but also Other elements not expressly listed, or inherent to the process, method, article, or apparatus are also included.

While preferred embodiments of the invention have been described, additional changes and modifications to these embodiments can be made by those skilled in the art once the basic inventive concept is appreciated. Therefore, it is intended that the appended claims be construed to cover the preferred embodiment as well as all changes and modifications which fall within the scope of the invention.

Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and equivalent technologies thereof, the present invention also intends to include these modifications and variations.

Claims (4)

1. A preparation method of a thermal insulation refractory prepared from hazardous waste, characterized in that the method comprises: The secondary aluminum ash is subjected to the first water washing pretreatment to obtain the pretreated secondary aluminum ash, the water quality of the first water washing pretreatment is 2.5-3.5 times the quality of the secondary aluminum ash, and the first water washing pretreatment The washing time of the treatment is 8min-12min, and the moisture content of the pretreated secondary aluminum ash is ≤2%; The recycled aluminum dedusting ash is subjected to the second water washing pretreatment to obtain the pretreated regenerated aluminum dedusting ash. The washing time of the treatment is 8min-12min, and the moisture content of the pretreated regenerated aluminum dedusting ash is ≤2%. The pretreated secondary aluminum ash, the pretreated regenerated aluminum dust and silicon-rich solid waste are mixed, and then ball milled to obtain a mixed raw meal. The raw materials of the mixed raw meal include: pretreated 60%-80% of secondary aluminum ash, 10%-35% of pretreated recycled aluminum dust and 5%-10% of silicon-rich solid waste; adding water and stirring the mixed raw meal to obtain wet raw meal; foam molding the wet raw material, and then drying to obtain a green body; Sintering the green body by increasing the temperature step by step to obtain a heat-insulating refractory material; In the step-by-stage temperature-raising sintering, When the sintering temperature is <300°C, the heating rate of the sintering is 2.5°C/min-3.5°C/min; When 300°C≤sintering temperature<600°C, the heating rate of the sintering is 4.5°C/min-5.5°C/min; When 600°C≤sintering temperature<1000°C, the heating rate of the sintering is 3.5°C/min-4.5°C/min; When 1000°C≤sintering temperature<final sintering temperature, the heating rate of the sintering is 2.5°C/min-3.5°C/min, and the final sintering temperature is 1200°C-1350°C; The silicon-rich solid waste includes at least one of fly ash and coal gangue; The particle size of the mixed raw meal is 160 mesh sieve. 2. The method for preparing thermal insulation refractory materials prepared from hazardous waste according to claim 1, characterized in that, in the stirring with water, the mass of water added is 30%-60% of the mass of the mixed raw meal. 3. The method for preparing thermal insulation refractory materials prepared from hazardous waste according to claim 1, characterized in that the foaming time is 25 minutes to 35 minutes. 4. The method for preparing thermal insulation refractory materials prepared from hazardous waste according to claim 1, wherein the moisture content of the green body is ≤2%.

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