Method for preparing autoclaved aerated concrete by using retired wind turbine blades and waste incineration fly ash

Abstract

The invention discloses a method for preparing autoclaved aerated concrete by using retired wind turbine blades and waste incineration fly ash. Dry substances of the aerated concrete comprise a wind turbine blade crushed material, water-washing incineration fly ash, gypsum, quick lime, cement and aluminum powder paste. According to the invention, two solid wastes, namely the retired wind turbine blade crushed material and the water-washing garbage incineration fly ash, are subjected to co-treatment; the decommissioned wind power blade is used as a siliceous raw material to make up the defect that the content of SiO2 in fly ash in washing waste incineration is low, the gelation activity of the fly ash and wind power blade crushed materials is improved through mechanical activation of a ball mill and an alkali activator, and the problems that aerated concrete raw materials are in shortage and the decommissioned wind power blade and washing waste incineration fly ash are difficult to recycle are solved.

Description

Technical Field

[0001] The invention belongs to the technical field of solid waste resource utilization, and specifically relates to a method for preparing autoclaved aerated concrete by utilizing retired wind turbine blades and waste incineration fly ash. Background Art

[0002] With the global emphasis on carbon emission reduction and the implementation of my country's "dual carbon" strategic goals, the development of wind power continues to remain vigorous. The service life of wind turbines is usually about 20 years, but due to the low efficiency of wind turbines and photovoltaic components produced in the past, component aging, reduced efficiency, facility damage, technology upgrades and other reasons, the actual service life has been greatly shortened. The wind turbine components produced ten years ago have entered the elimination period ahead of schedule. After each megawatt of wind power equipment is retired, 100 to 240 tons of steel, copper, aluminum, glass fiber and other materials can be recycled. The non-degradable materials in wind turbine blades will have an adverse impact on the environment and ecosystem. Waste wind turbine components have the dual attributes of "resource" and "pollution". The resource utilization under the premise of harmlessness is an inevitable requirement for the development of the wind power green energy industry and the realization of the "dual carbon" goals.

[0003] Incineration of domestic waste is one of the mainstream technologies in my country at present, and incineration is inevitably accompanied by the generation of fly ash. The "National List of Hazardous Wastes (2021 Edition)" clearly states that fly ash from the incineration of domestic waste is a hazardous waste. Its safe treatment and disposal is the "last mile" in the construction of a "zero-waste city", and the resource utilization of fly ash has become a trend.

[0004] Comprehensively comparing the benefits and utilization rates, the most efficient way to recycle bulk solid waste is to use it as building materials. Aerated concrete blocks are a porous, heat-insulating and energy-saving material that can absorb a large amount of solid waste. They are widely used in building envelope structures. In recent years, due to market demand, natural sand and other raw materials are in short supply, and new sources of materials need to be found.

[0005] At present, the research and application of retired wind turbine blades and washed incineration fly ash resources have made certain progress: Chinese patent application CN110526364A provides a method for preparing polysilicate aluminum iron flocculant using waste incineration fly ash, Chinese patent application CN114163150A provides a method for preparing cementitious materials using water-washed waste incineration fly ash, Chinese patent application CN115466096A discloses a lightweight prefabricated insulation brick made of alkali-activated waste incineration fly ash and its preparation method, Chinese patent application CN118768359A discloses a system and method for in-situ pyrolysis recovery of retired wind turbine blades, and Chinese patent application CN118684836A discloses a wind turbine blade regeneration composite material and its preparation method and application. The above applications are all the separate utilization of wind turbine blades or fly ash, and there is currently no method for synergistically applying wind turbine blades and fly ash to concrete. Summary of the invention

[0006] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a method for preparing autoclaved aerated concrete using retired wind turbine blades and waste incineration fly ash. The present invention optimizes the chemical components and reaction activity of the materials by fully mixing the crushed materials of retired wind turbine samples with washed fly ash and subjecting them to mechanical activation and alkaline excitation, thereby improving the utilization rate and activity of washed fly ash. Compared with the prior art, the use of retired wind turbine blades and washed waste incineration fly ash to synergistically prepare autoclaved aerated concrete can achieve solid waste resource utilization and environmental benefit improvement in accordance with GB / T11968 standards without generating secondary pollution, and can safely utilize new energy solid waste and hazardous waste, with high social and environmental benefits, and has a positive impact on reality.

[0007] The technical solution of the present invention is specifically described as follows.

[0008] A method for preparing autoclaved aerated concrete using retired wind turbine blades and waste incineration fly ash, comprising the following steps: Step 1: ball milling the cut and crushed retired wind turbine blades; Step 2: calcining the washed waste incineration fly ash to increase the CaO content and activity; Step 3: Mechanically activate the ball-milled wind turbine blades, washed waste incineration fly ash and alkaline activator according to the proportions; Step 4: Put the mechanically activated material into a mixer, add gypsum and stir for a certain period of time to obtain a dry mix, then add warm water, cement and quicklime and stir, after stirring evenly, add the aluminum powder suspension into the slurry and stir thoroughly; Step 5: pouring the slurry obtained in step 4 into a steel mold to form a green body, and placing the cast green body into a curing room for pre-curing, so that the aluminum powder and other materials can fully react and generate gas during the thickening process, and obtain a certain hardness; Step 6: After the pre-curing is completed, the green body is taken out and cut with a cutting machine to remove the overflowed bread heads; Step 7: Place the blocks in an autoclave for constant pressure autoclaving and curing. After curing, take them out and cool them naturally to obtain autoclaved aerated concrete blocks.

[0009] In the present invention, based on the total mass of dry matter of cement, quicklime, gypsum, washed waste incineration fly ash, wind turbine blade crushing material and alkaline activator meeting 100%, the raw material components are as follows: 15% to 25% of cement, 4% to 8% of quicklime, 3% to 4.5% of gypsum, 20% to 35% of washed waste incineration fly ash, 25% to 40% of wind turbine blade crushing material, 1% to 3% of alkaline activator and 0.06% to 0.16% of aluminum powder paste.

[0010] In the present invention, in step 1, the wind turbine blades are retired wind turbine blade materials that have been cut and crushed to 1-3 mm and mechanically ball-milled, the ball-milling speed is 200-300 r / min, the ball-milling time is 15-30 min, and the material is sieved through a 100-mesh sieve after ball-milling.

[0011] In the present invention, in step 2, the water-washed waste incineration fly ash complies with the "Technical Specification for Pollution Control of Domestic Waste Incineration Fly Ash" (HJ 1134-2020), the heavy metal leaching concentration does not exceed the maximum limit of the standard hazardous waste identification standard (GB 5085.3-2007), the SiO2 mass fraction is 2-10%, the CaO mass fraction is 40-55%, and the Cl - The mass fraction of washed waste incineration fly ash is less than 1%; the calcination temperature of washed waste incineration fly ash is 500~700℃, and the calcination time is 1~2h.

[0012] In the present invention, in step 3, the ball milling speed is 300-400 r / min, and the ball milling time is 30-60 min.

[0013] In the present invention, in step 4, the mass ratio of warm water to dry material is 0.5:1-0.7:1, and the temperature of the warm water is 45-55°C.

[0014] In the present invention, in step 4, after the materials are stirred evenly, the aluminum powder suspension is added to the slurry and stirred for 30 to 60 seconds.

[0015] In the present invention, in step 5, the pre-curing is performed at a temperature of 55-65° C. and a humidity of 80%-90% for 8-10 hours.

[0016] In the present invention, in step 7, constant pressure autoclave curing is performed at a temperature of 175-190° C. and a pressure of 1.2-1.4 MPa for 8-10 hours.

[0017] Compared with the prior art, the present invention has the following beneficial effects: By utilizing the silicon content and fiber reinforcement characteristics of retired wind turbine blades and combining them with the high calcium content in waste incineration fly ash, the silicon-calcium ratio in the blocks is made more reasonable. More tobermorite crystalline products can be formed through hydrothermal synthesis reaction during the autoclaving process, thereby improving the strength of the aerated concrete blocks.

[0018] Mechanical activation is used to promote the destruction of wind turbine blade materials and water-washed fly ash, and the activity of silicon in the blade material is enhanced, which is beneficial to the interaction and reaction of alkaline activators (sodium silicate).

[0019] By roasting the washed waste incineration fly ash, the CaO content and activity in the fly ash can be increased, the consumption of natural lime and other resources can be reduced, and the harm to the environment caused by retired wind turbine blades and waste incineration fly ash can be reduced, which has positive environmental benefits and practical significance. DETAILED DESCRIPTION

[0020] The present invention is further described in detail below with reference to examples, but the protection scope of the present invention is not limited to the scope represented by the embodiments.

[0021] In the embodiment, the retired wind turbine blades are cut, crushed and mechanically ball-milled to a particle size of <0.15 mm; the fly ash from the incineration of garbage is the fly ash from the incineration plant after water washing. - <1%.

[0022] Example 1

[0023] An autoclaved aerated concrete using retired wind turbine blades and waste incineration fly ash, wherein the total mass of dry matter raw materials of cement, quicklime, gypsum, washed waste incineration fly ash, wind turbine blade crushing material and alkaline activator meets 100%, and the raw material composition is as follows: Cement 20% Quicklime 4% Gypsum 3% Washed waste incineration fly ash 35% Wind turbine blade crushed material 37% Aluminum powder paste 0.07% Alkaline stimulant 1% Water to material ratio 0.6 The specific preparation method is as follows: Step 1: ball-mill the cut and crushed retired wind turbine blades and sieve them through a 100-mesh screen; Step 2: calcining the washed waste incineration fly ash at 600°C for 1h; Step 3: mechanically activate the ball-milled wind turbine blades, the calcined washed waste incineration fly ash and the alkaline activator according to the proportion, with the ball milling time being 30 minutes and the rotation speed being 300 r / min; Step 4: Put the mechanically activated wind turbine blades, washed fly ash and alkaline activator into a mixer, add gypsum and stir for 10 minutes to obtain a dry mix, then add warm water, cement and lime and stir for 5 minutes. After stirring evenly, add aluminum powder suspension (aluminum powder suspension is made from aluminum powder paste for standby use, added by external mixing method, not included in the calculation of dry matter) into the slurry and stir thoroughly for 30 seconds; Step 5: pouring the slurry obtained in step 4 into a steel mold to form a green body, and placing the cast green body in a curing room for pre-curing for 8 hours to allow the aluminum powder and other materials to fully react and generate gas during the thickening process; Step 6: After the pre-curing is completed, the green body is taken out and cut with a cutting machine to remove the overflowed bread heads; Step 7: Place the blocks in an autoclave and autoclave them for curing at a constant pressure of 180°C and 1.2 MPa for 8 hours. Take them out and cool them naturally to obtain autoclaved aerated concrete blocks.

[0024] According to GB / T11969-2020 "Test method for performance of autoclaved aerated concrete blocks", the dry density of the blocks is 615kg / m 3 , the compressive strength is 4.5MPa.

[0025] Example 2

[0026] An autoclaved aerated concrete using retired wind turbine blades and waste incineration fly ash, wherein the total mass of dry matter raw materials of cement, quicklime, gypsum, washed waste incineration fly ash, wind turbine blade crushing material and alkaline activator meets 100%, and the specific composition of the raw materials is as follows: Cement 25% Quicklime 5% Gypsum 3.5% Washed waste incineration fly ash 30% Wind turbine blade crushing material 35% Aluminum powder paste 0.07% Alkaline activator 1.5% Water to material ratio 0.6 The specific preparation method is as follows: Step 1: ball-mill the cut and crushed retired wind turbine blades and sieve them through a 100-mesh screen; Step 2: calcining the washed waste incineration fly ash at 550°C for 1.5h; Step 3: Mechanically activate the ball-milled wind turbine blades, the washed waste incineration fly ash after roasting and the alkaline activator according to the proportion, with the ball milling time being 45 minutes and the rotation speed being 350 r / min; Step 4: Put the mechanically activated wind turbine blades, washed fly ash and alkaline activator into a mixer, add gypsum and stir for 10 minutes to obtain a dry mix, then add warm water, cement and lime and stir for 5 minutes. After stirring evenly, add aluminum powder suspension (aluminum powder suspension is made from aluminum powder paste for standby use, added by external mixing method, not included in the calculation of dry matter) into the slurry and stir thoroughly for 40 seconds; Step 5: pouring the slurry obtained in step 4 into a steel mold to form a green body, and placing the cast green body into a curing room for pre-curing for 9 hours to allow the aluminum powder and other materials to fully react and generate gas during the thickening process; Step 6: After the pre-curing is completed, the green body is taken out and cut with a cutting machine to remove the overflowed bread heads; Step 7: Place the blocks in an autoclave and autoclave them for curing at a constant pressure of 185°C and 1.3 MPa for 9 hours. Take them out and cool them naturally to obtain autoclaved aerated concrete blocks.

[0027] According to GB / T11969-2020 "Test method for performance of autoclaved aerated concrete blocks", the dry density of the blocks was measured to be 595kg / m3 and the compressive strength was 5.1MPa.

[0028] Example 3

[0029] An autoclaved aerated concrete using retired wind turbine blades and waste incineration fly ash, wherein the total mass of dry matter raw materials of cement, quicklime, gypsum, washed waste incineration fly ash, wind turbine blade crushing material and alkaline activator meets 100%, and the specific composition of the raw materials is as follows: Cement 23% Quicklime 3.5% Gypsum 3% Washed waste incineration fly ash 33% Wind turbine blade crushing material 36% Aluminum powder paste 0.07% Alkaline activator 1.5% Water to material ratio 0.6 The specific preparation method is as follows: Step 1: ball-mill the cut and crushed retired wind turbine blades and sieve them through a 100-mesh screen; Step 2: calcining the washed waste incineration fly ash at 650°C for 1.5h; Step 3: mechanically activate the ball-milled wind turbine blades, the calcined washed waste incineration fly ash and the alkaline activator according to the proportion, with the ball milling time being 60 minutes and the rotation speed being 300 r / min; Step 4: Put the mechanically activated wind turbine blades, washed fly ash and alkaline activator into a mixer, add gypsum and stir for 12 minutes to obtain a dry mix, then add warm water, cement and lime and stir for 7 minutes. After stirring evenly, add aluminum powder suspension (aluminum powder suspension is made from aluminum powder paste for standby use, added by external mixing method, not included in the calculation of dry matter) into the slurry and stir thoroughly for 60 seconds; Step 5: pouring the slurry obtained in step 4 into a steel mold to form a green body, and placing the cast green body in a curing room for pre-curing for 8 hours to allow the aluminum powder and other materials to fully react and generate gas during the thickening process; Step 6: After the pre-curing is completed, the green body is taken out and cut with a cutting machine to remove the overflowed bread heads; Step 7: Place the blocks in an autoclave and autoclave them for curing at a constant pressure of 190°C and 1.4 MPa for 9 hours. Take them out and cool them naturally to obtain autoclaved aerated concrete blocks.

[0030] According to GB / T11969-2020 "Test method for performance of autoclaved aerated concrete blocks", the dry density of the blocks was measured to be 580kg / m3 and the compressive strength was 4.9MPa.

[0031] Comparative Example 1 An autoclaved aerated concrete using retired wind turbine blades and waste incineration fly ash, wherein no alkaline activator is used, wherein the total mass of dry matter raw materials of cement, quicklime, gypsum, washed waste incineration fly ash and wind turbine blade crushed material meets 100%, and the raw material composition is as follows: Cement 23% Quicklime 5% Gypsum 3% Washed waste incineration fly ash 33% Wind turbine blade crushing material 36% Aluminum powder paste 0.07% Water to material ratio 0.6 The specific preparation method is as follows: Step 1: ball-mill the cut and crushed retired wind turbine blades and sieve them through a 100-mesh screen; Step 2: calcining the washed waste incineration fly ash at 650°C for 1.5h; Step 3: Mechanically activate the ball-milled wind turbine blades and the washed waste incineration fly ash after roasting according to the proportion, with the ball milling time being 60 minutes and the rotation speed being 300 r / min; Step 4: Put the mechanically activated wind turbine blades, washed fly ash and alkaline activator into a mixer, add gypsum and stir for 12 minutes to obtain a dry mix, then add warm water, cement and lime and stir for 7 minutes. After stirring evenly, add aluminum powder suspension (aluminum powder suspension is made from aluminum powder paste for standby use, added by external mixing method, not included in the calculation of dry matter) into the slurry and stir thoroughly for 60 seconds; Step 5: pouring the slurry obtained in step 4 into a steel mold to form a green body, and placing the cast green body in a curing room for pre-curing for 8 hours to allow the aluminum powder and other materials to fully react and generate gas during the thickening process; Step 6: After the pre-curing is completed, the green body is taken out and cut with a cutting machine to remove the overflowed bread heads; Step 7: Place the blocks in an autoclave and autoclave them for curing at a constant pressure of 190°C and 1.4 MPa for 9 hours. Take them out and cool them naturally to obtain autoclaved aerated concrete blocks.

[0032] According to GB / T11969-2020 "Test method for performance of autoclaved aerated concrete blocks", the dry density of the blocks was measured to be 680kg / m3 and the compressive strength was 3.9MPa.

[0033] Comparative Example 2 An autoclaved aerated concrete using retired wind turbine blades and waste incineration fly ash is prepared from the following raw materials in percentage by mass. During the preparation process, the wind turbine blades, the calcined washed waste incineration fly ash and the alkaline activator are only stirred and mixed without mechanical activation treatment. The specific composition of the raw materials is as follows, based on the total mass of the dry raw materials of cement, quicklime, gypsum, washed waste incineration fly ash, wind turbine blade crushed material and alkaline activator meeting 100%: Cement 23% Quicklime 3.5% Gypsum 3% Washed waste incineration fly ash 33% Wind turbine blade crushing material 36% Aluminum powder paste 0.07% Alkaline activator 1.5% Water to material ratio 0.6 The specific preparation method is as follows: Step 1: ball-mill the cut and crushed retired wind turbine blades and sieve them through a 100-mesh screen; Step 2: calcining the washed waste incineration fly ash at 650°C for 1.5h; Step 3: Put the mechanically activated wind turbine blades, washed fly ash and alkaline activator into a mixer, add gypsum and stir for 12 minutes to obtain a dry mix, then add warm water, cement and lime and stir for 7 minutes. After stirring evenly, add aluminum powder suspension (aluminum powder suspension is made from aluminum powder paste for standby use, added by external mixing method, not included in the calculation of dry matter) into the slurry and stir thoroughly for 60 seconds; Step 4: pouring the slurry obtained in step 4 into a steel mold to form a green body, and placing the cast green body into a curing room for pre-curing for 8 hours to allow the aluminum powder and other materials to fully react and generate gas during the thickening process; Step 5: After the pre-curing is completed, the green body is taken out and cut with a cutting machine to remove the overflowed bread heads; Step 6: Place the blocks in an autoclave and autoclave them for curing at a constant pressure of 190°C and 1.4 MPa for 9 hours. Take them out and cool them naturally to obtain autoclaved aerated concrete blocks.

[0034] According to GB / T11969-2020 "Test method for performance of autoclaved aerated concrete blocks", the dry density of the blocks was measured to be 630kg / m3 and the compressive strength was 4.2MPa.

Claims

1. A method for preparing autoclaved aerated concrete using retired wind turbine blades and waste incineration fly ash, characterized in that: The following steps are involved: Step 1: ball milling the cut and crushed retired wind turbine blades; Step 2: calcining the washed waste incineration fly ash to increase the CaO content and activity; Step 3: Mechanically activate the ball-milled wind turbine blades, washed waste incineration fly ash and alkaline activator according to the proportions; Step 4: Put the mechanically activated material into a mixer, add gypsum and stir for a certain period of time to obtain a dry mix, then add warm water, cement and quicklime and stir, after stirring evenly, add the aluminum powder suspension into the slurry and stir thoroughly; Step 5: pouring the slurry obtained in step 4 into a steel mold to form a green body, and placing the cast green body into a curing room for pre-curing, so that the aluminum powder and other materials can fully react and generate gas during the thickening process, and obtain a certain hardness; Step 6: After the pre-curing is completed, the green body is taken out and cut with a cutting machine to remove the overflowed bread heads; Step 7: Place the blocks in an autoclave for constant pressure autoclaving and curing. After curing, take them out and cool them naturally to obtain autoclaved aerated concrete blocks.

2. The method according to claim 1, characterized in that Based on the total mass of dry matter of cement, quicklime, gypsum, washed waste incineration fly ash, crushed wind turbine blades and alkaline activator meeting 100%, the raw material components are as follows: 15% to 25% of cement, 4% to 8% of quicklime, 3% to 4.5% of gypsum, 20% to 35% of washed waste incineration fly ash, 25% to 40% of crushed wind turbine blades, 1% to 3% of alkaline activator and 0.06% to 0.16% of aluminum paste.

3. The method according to claim 1, characterized in that In step 1, the ball milling speed is 200-300 r / min, the ball milling time is 15-30 min, and the product is sieved through a 100-mesh sieve after ball milling.

4. The method according to claim 1, wherein: In step 2, in the washed waste incineration fly ash, the mass fraction of SiO2 is 2-10%, the mass fraction of CaO is 40-55%, and the mass fraction of Cl- is less than 1%; the roasting temperature is 500-700°C, and the time is 1-2h.

5. The method according to claim 1, characterized in that In step 3, during mechanical activation, the ball milling speed is 300-400 r / min, and the ball milling time is 30-60 min.

6. The method according to claim 1, characterized in that In step 4, the mass ratio of warm water to dry material is 0.5:1-0.7:1, and the temperature of the warm water is 45-55°C.

7. The method according to claim 1, characterized in that In step 4, after the materials are evenly stirred, the aluminum powder suspension is added to the slurry and stirred for 30 to 60 seconds.

8. The method according to claim 1, characterized in that In step 5, pre-curing is carried out at a temperature of 55-65°C and a humidity of 80%-90% for 8-10 hours.

9. The method according to claim 1, characterized in that In step 7, constant pressure autoclave curing is performed at a temperature of 175-190° C. and a pressure of 1.2-1.4 MPa for 8-10 hours.

10. Autoclaved aerated concrete obtained by the method according to any one of claims 1 to 9.