CN117658570A - Cement-free high-strength baking-free lightweight aggregate prepared from coal gangue and red mud and method - Google Patents
Cement-free high-strength baking-free lightweight aggregate prepared from coal gangue and red mud and method Download PDFInfo
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- CN117658570A CN117658570A CN202311636501.4A CN202311636501A CN117658570A CN 117658570 A CN117658570 A CN 117658570A CN 202311636501 A CN202311636501 A CN 202311636501A CN 117658570 A CN117658570 A CN 117658570A
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- 239000003245 coal Substances 0.000 title claims abstract description 48
- 238000000034 method Methods 0.000 title claims abstract description 26
- AXCZMVOFGPJBDE-UHFFFAOYSA-L calcium dihydroxide Chemical compound [OH-].[OH-].[Ca+2] AXCZMVOFGPJBDE-UHFFFAOYSA-L 0.000 claims abstract description 21
- 239000000920 calcium hydroxide Substances 0.000 claims abstract description 21
- 235000011116 calcium hydroxide Nutrition 0.000 claims abstract description 21
- 229910001861 calcium hydroxide Inorganic materials 0.000 claims abstract description 21
- 239000002245 particle Substances 0.000 claims description 36
- 239000000203 mixture Substances 0.000 claims description 14
- 238000001354 calcination Methods 0.000 claims description 12
- 238000000227 grinding Methods 0.000 claims description 12
- 230000032683 aging Effects 0.000 claims description 8
- 239000008188 pellet Substances 0.000 claims description 8
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 8
- 238000001035 drying Methods 0.000 claims description 7
- 238000002156 mixing Methods 0.000 claims description 4
- 238000005469 granulation Methods 0.000 claims description 2
- 230000003179 granulation Effects 0.000 claims description 2
- 238000002360 preparation method Methods 0.000 abstract description 11
- 239000002910 solid waste Substances 0.000 abstract description 10
- 238000005245 sintering Methods 0.000 abstract description 7
- 229910018072 Al 2 O 3 Inorganic materials 0.000 abstract description 6
- 238000006703 hydration reaction Methods 0.000 abstract description 6
- 238000004519 manufacturing process Methods 0.000 abstract description 5
- 239000002994 raw material Substances 0.000 abstract description 5
- 238000004064 recycling Methods 0.000 abstract description 4
- 239000000378 calcium silicate Substances 0.000 abstract description 3
- 229910052918 calcium silicate Inorganic materials 0.000 abstract description 3
- OYACROKNLOSFPA-UHFFFAOYSA-N calcium;dioxido(oxo)silane Chemical compound [Ca+2].[O-][Si]([O-])=O OYACROKNLOSFPA-UHFFFAOYSA-N 0.000 abstract description 3
- 238000011161 development Methods 0.000 abstract description 3
- 230000036571 hydration Effects 0.000 abstract description 3
- 239000000126 substance Substances 0.000 abstract description 2
- 238000001816 cooling Methods 0.000 description 10
- 238000003756 stirring Methods 0.000 description 10
- ODINCKMPIJJUCX-UHFFFAOYSA-N Calcium oxide Chemical compound [Ca]=O ODINCKMPIJJUCX-UHFFFAOYSA-N 0.000 description 8
- 230000000052 comparative effect Effects 0.000 description 7
- 239000004568 cement Substances 0.000 description 5
- 238000007580 dry-mixing Methods 0.000 description 5
- 230000000694 effects Effects 0.000 description 5
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 5
- 238000005259 measurement Methods 0.000 description 5
- 238000007873 sieving Methods 0.000 description 5
- 238000005303 weighing Methods 0.000 description 5
- 239000000292 calcium oxide Substances 0.000 description 4
- 235000012255 calcium oxide Nutrition 0.000 description 4
- 238000006243 chemical reaction Methods 0.000 description 4
- 230000002195 synergetic effect Effects 0.000 description 4
- 229910004298 SiO 2 Inorganic materials 0.000 description 3
- 239000012467 final product Substances 0.000 description 3
- 239000002893 slag Substances 0.000 description 3
- 239000010802 sludge Substances 0.000 description 3
- CSDREXVUYHZDNP-UHFFFAOYSA-N alumanylidynesilicon Chemical compound [Al].[Si] CSDREXVUYHZDNP-UHFFFAOYSA-N 0.000 description 2
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 2
- 230000018109 developmental process Effects 0.000 description 2
- 238000009713 electroplating Methods 0.000 description 2
- 239000010881 fly ash Substances 0.000 description 2
- 238000003837 high-temperature calcination Methods 0.000 description 2
- 229910052742 iron Inorganic materials 0.000 description 2
- 239000011499 joint compound Substances 0.000 description 2
- 238000011031 large-scale manufacturing process Methods 0.000 description 2
- 239000000178 monomer Substances 0.000 description 2
- 239000000047 product Substances 0.000 description 2
- 238000010998 test method Methods 0.000 description 2
- 238000004131 Bayer process Methods 0.000 description 1
- 229910000831 Steel Inorganic materials 0.000 description 1
- KMWBBMXGHHLDKL-UHFFFAOYSA-N [AlH3].[Si] Chemical group [AlH3].[Si] KMWBBMXGHHLDKL-UHFFFAOYSA-N 0.000 description 1
- 239000002956 ash Substances 0.000 description 1
- 229910001570 bauxite Inorganic materials 0.000 description 1
- PASHVRUKOFIRIK-UHFFFAOYSA-L calcium sulfate dihydrate Chemical compound O.O.[Ca+2].[O-]S([O-])(=O)=O PASHVRUKOFIRIK-UHFFFAOYSA-L 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 239000004927 clay Substances 0.000 description 1
- 230000000295 complement effect Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 230000008020 evaporation Effects 0.000 description 1
- 230000005284 excitation Effects 0.000 description 1
- 239000000945 filler Substances 0.000 description 1
- 238000010304 firing Methods 0.000 description 1
- 238000001879 gelation Methods 0.000 description 1
- 239000003349 gelling agent Substances 0.000 description 1
- 229910052602 gypsum Inorganic materials 0.000 description 1
- 239000010440 gypsum Substances 0.000 description 1
- 229910052500 inorganic mineral Inorganic materials 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 235000010755 mineral Nutrition 0.000 description 1
- 239000011707 mineral Substances 0.000 description 1
- 238000005065 mining Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 229920000642 polymer Polymers 0.000 description 1
- 238000004321 preservation Methods 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicon dioxide Inorganic materials O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
- 230000002459 sustained effect Effects 0.000 description 1
- 238000005406 washing Methods 0.000 description 1
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
- Y02W30/00—Technologies for solid waste management
- Y02W30/50—Reuse, recycling or recovery technologies
- Y02W30/91—Use of waste materials as fillers for mortars or concrete
Landscapes
- Treatment Of Sludge (AREA)
Abstract
The invention discloses a cement-free high-strength baking-free lightweight aggregate prepared by utilizing gangue and red mud and a method thereof, wherein an alkaline hydration environment is formed by adding slaked lime and red mud, and active SiO in pretreated gangue is prepared by the method 2 Active Al 2 O 3 Hydration reaction occurs to generate gelled substances such as calcium silicate hydrate and the like, and the strength of the lightweight aggregate is provided. The pressure intensity of the prepared cement-free baking-free lightweight aggregate cylinder is 6.8-7.9 MPa, and the bulk density is 858-890 kg/m 3 The softening coefficient is more than 0.8, can be used for building aggregate, and is a green lightweight aggregate with development potential. The raw materials of coal gangue and red mud used in the invention are solid wastes, the total consumption of the solid wastes is more than 80%, sintering and steam curing are not needed, the production cost is low, the preparation process is simple, and the scale is easy to realizeThe method has important significance for realizing the recycling of the coal gangue and the red mud, and has wide market prospect.
Description
Technical Field
The invention relates to the technical field of resource recycling, in particular to a cement-free high-strength baking-free lightweight aggregate prepared from coal gangue and red mud and a method thereof.
Background
The gangue is solid waste produced in the coal mining process and the coal washing process, and the main component is SiO 2 、Al 2 O 3 CaO, etc. The red mud is industrial solid waste discharged after alumina is extracted from bauxite, and the main component is SiO 2 、Al 2 O 3 、CaO、Fe 2 O 3 The pH is very high. The utilization rate of the gangue and the red mud is low, and the stockpiling amount is larger and larger, so that not only is a large amount of land occupied, but also serious pollution is caused to the environment, and the utilization of the gangue and the red mud to the maximum extent is not sustained. The preparation of lightweight aggregate by utilizing gangue and red mud is one of the effective recycling ways.
The method disclosed at present adopts high-temperature calcination, autoclaved curing and cement addition to prepare the lightweight aggregate. Chinese patent application CN113698175A discloses a gangue haydite and a preparation method thereof, wherein gangue, clay, shale and quicklime are utilized to fire the haydite, and the firing temperature is 1050-1150 ℃; chinese patent application CN116639993a discloses a new method for preparing ceramsite by co-processing coal gangue and sludge, wherein the temperature of sintering ceramsite is 800-1300 ℃; chinese patent application CN115849935a discloses a method for preparing gangue-based high-strength ceramsite, which comprises mixing crushed and ground gangue, steel slag, phosphogypsum or desulfurized gypsum according to a preset proportion to prepare ceramsite, wherein the roasting temperature is 1000-1200 ℃, and the heat preservation time is 30-120 min; chinese patent application CN113912376a discloses a baking-free ceramsite processed by solid waste of red mud, fly ash, iron tailings and carbide slag, and preparation method and application thereof, wherein red mud, fly ash, iron tailings and carbide slag are used as raw materials, and autoclaved curing is performed at 70-90 ℃ to prepare the ceramsite, and the cylinder pressure is 3.3-4.2 MPa; chinese patent application CNCN115636623A discloses a baking-free haydite, a preparation method and application thereof, wherein the autoclaved temperature is 170-200 ℃, and the cylinder pressure is 6.5-8 MPa; chinese patent application CN115215621a discloses a method for preparing baking-free ceramsite by electroplating sludge, which uses electroplating sludge, gangue and quicklime to prepare ceramsite, thus realizing baking-free process, but still using cement as gelling agent, and increasing production cost. The existing method can utilize solid waste to prepare the lightweight aggregate and meet the performance requirement of the lightweight aggregate, but the high-temperature calcination consumes a large amount of energy, autoclaved maintenance and cement use, so that the production cost is increased.
Disclosure of Invention
Aiming at the defects of the prior art, the invention aims to provide a cement-free high-strength baking-free lightweight aggregate prepared by using coal gangue and red mud and a method thereof.
In order to achieve the above purpose, the present invention adopts the following technical scheme:
the cement-free high-strength baking-free lightweight aggregate prepared from coal gangue and red mud is prepared from, by weight, 55-60 parts of coal gangue, 20-25 parts of red mud and 15-20 parts of slaked lime.
Further, the red mud is sintered red mud, and the particle size of the red mud is smaller than 0.15mm. In the cement-free high-strength baking-free lightweight aggregate, the main function of the red mud is to participate in the synergistic reaction and serve as a filler, and the particle size of the red mud is too large to be beneficial to the synergistic reaction. The sintering process red mud has better activity than Bayer process red mud.
Further, ca (OH) in the slaked lime 2 The mass content of (2) is more than 90%.
Further, the gangue is crushed to a particle size of less than 4.75mm, then calcined in a muffle furnace at 680-750 ℃ for 6 hours, cooled and ground to a particle size of less than 0.075mm. The coal gangue is pretreated to generate active SiO 2 And active Al 2 O 3 So as to have pozzolanic activity. In addition, the too large particle size of the gangue is unfavorable for the excitation of activity and the progress of synergistic reaction.
The invention also provides a method for preparing the cement-free high-strength baking-free lightweight aggregate by using the coal gangue and the red mud, which comprises the steps of mixing 55-60 parts of the coal gangue, 20-25 parts of the red mud and 15-20 parts of slaked lime to obtain a uniform mixture, adding the mixture into granulating equipment, adding water for granulating, and finally aging, drying and dehydrating the pellets to obtain the cement-free high-strength baking-free lightweight aggregate.
The purpose of aging is to ensure that the gangue is fully hydrated in an alkaline environment to form hydrated calcium silicate with gelation, so that the strength of the lightweight aggregate is improved, and meanwhile, cracks caused by too fast evaporation of moisture in wet balls are prevented.
Further, in the method, before mixing, the gangue and the red mud are pretreated, wherein the gangue is crushed to a particle size smaller than 4.75mm, the crushed gangue particles are put into a muffle furnace, calcined for 6 hours at 680-750 ℃, immediately taken out of the muffle furnace after the calcination is finished, cooled in air, cooled to room temperature and ground to a particle size smaller than 0.075mm; for red mud, grinding the red mud to a particle size of less than 0.15mm.
Further, in the method, after granulation, the produced pellets are screened, the pellets with the diameter of 10-15 mm are selected, and then the selected pellets are aged, dried and dehydrated.
Further, in the above method, the aging time is 6-8 days, and the drying and dehydrating temperature is below 80 ℃.
The invention has the beneficial effects that:
1. the strength of the traditional lightweight aggregate is mainly provided by cement and other gelatinizing agents through hydration, high-temperature sintering and autoclaved curing, while the strength of the lightweight aggregate is provided by slaked lime and red mud which are alkaline-activated to activate the volcanic ash activity of the gangue, and an alkaline hydration environment is formed by adding the slaked lime and the red mud, so that the activated SiO in the pretreated gangue is obtained 2 Active Al 2 O 3 Hydration reaction occurs to generate gelled substances such as calcium silicate hydrate and the like, and the strength of the lightweight aggregate is provided.
2. The pressure strength of the non-sintered lightweight aggregate cylinder prepared by the invention is 6.8-7.9 MPa, and the bulk density is 858-890 kg/m 3 The softening coefficient is larger than 0.8, meets the requirement of high-strength lightweight aggregate in the standard GB/T17431.1-2010 of lightweight aggregate and test method 1 part thereof, can be used for building aggregate, and is green lightweight aggregate with development potential.
3. The raw materials of coal gangue and red mud used in the invention are solid wastes, the total solid waste consumption is more than 80%, sintering and steam curing are not needed, the production cost is low, the preparation process is simple, the large-scale production is easy to realize, and the method has important significance for realizing the recycling of the coal gangue and the red mud and has wide market prospect.
Drawings
FIG. 1 is a flow chart of the preparation process of the non-sintered lightweight aggregate without cement in examples 1-5 of the invention;
fig. 2 is a photograph of a cement-free high-strength baking-free lightweight aggregate product prepared in example 1 of the present invention.
Detailed Description
The present invention will be further described with reference to the accompanying drawings, and it should be noted that, while the present embodiment provides a detailed implementation and a specific operation process on the premise of the present technical solution, the protection scope of the present invention is not limited to the present embodiment.
Example 1
As shown in fig. 1, coal gangue and sintered red mud are pretreated. Crushing the coal gangue to a particle size of less than 4.75mm, putting crushed coal gangue particles into a muffle furnace, calcining for 6 hours at 750 ℃, immediately taking out the crushed coal gangue from the muffle furnace after calcining, cooling the crushed coal gangue in air, cooling the crushed coal gangue to a room temperature, and grinding the crushed coal gangue to a particle size of less than 0.075mm; and grinding the sintered red mud to a particle size of less than 0.15mm.
Weighing 3kg of gangue, 1kg of sintered red mud and 1kg of slaked lime, putting into a stirring container, and dry-mixing and stirring uniformly to obtain a mixture. Adding the obtained mixture into granulating equipment, adjusting the water quantity for granulating, sieving the produced balls, and selecting balls with the diameter of 10-15 mm; the selected pellets were then aged for 6 days and dried at 75 ℃ to dewater to give a cement-free high strength burn-free lightweight aggregate as shown in figure 2.
Under the alkaline action provided by slaked lime and red mud, the activity SiO in pretreated gangue is as follows 2 And active Al 2 O 3 And (3) carrying out hydration reaction to generate CSH and CAH gel, wherein mineral silica bonds and aluminum-oxygen bonds in the red mud are destroyed in an alkaline environment, silicon-aluminum monomers are dissolved, then the monomers are polymerized into oligomers to form gel, and finally the silicon-aluminum structure is polymerized to form high polymer silicon-aluminum polymerized gel. CSH, CAH and silica-alumina polymerized gel jointly become a base material with light aggregate strength, and a synergistic complementary reaction mechanism is formed among the three raw materials.
The cement-free high-strength baking-free lightweight aggregate prepared in the embodiment is subjected to performance measurement of barrel pressure strength, bulk density and softening coefficient, and the result shows that the barrel pressure strength of the cement-free high-strength baking-free lightweight aggregate prepared in the embodiment is 7.6Mpa, and the bulk density is 872kg/m 3 The softening coefficient was 0.87.
Example 2
As shown in fig. 1, coal gangue and sintered red mud are pretreated. Crushing coal gangue to a particle size of less than 4.75mm, putting crushed coal gangue particles into a muffle furnace, calcining at 740 ℃ for 6 hours, immediately taking out from the muffle furnace after calcining, putting into air for cooling, and grinding to a particle size of less than 0.075mm after cooling to room temperature; and grinding the sintered red mud to a particle size of less than 0.15mm.
Weighing 2.75kg of gangue, 1.25kg of sintered red mud and 1kg of slaked lime, putting into a stirring container, and dry-mixing and stirring uniformly to obtain a mixture. Adding the obtained mixture into granulating equipment, adjusting the water quantity for granulating, sieving the produced balls, and selecting balls with the diameter of 10-15 mm; and then aging the selected balls for 7 days and drying and dehydrating at 70 ℃ to obtain the cement-free high-strength baking-free lightweight aggregate.
The cement-free high-strength baking-free lightweight aggregate prepared in the embodiment is subjected to performance measurement of barrel pressure strength, bulk density and softening coefficient, and the result shows that the barrel pressure strength of the cement-free high-strength baking-free lightweight aggregate prepared in the embodiment is 7.9Mpa and the bulk density is 880kg/m 3 The softening factor was 0.86.
Example 3
As shown in fig. 1, coal gangue and sintered red mud are pretreated. Crushing coal gangue to a particle size of less than 4.75mm, putting crushed coal gangue particles into a muffle furnace, calcining at 720 ℃ for 6 hours, immediately taking out from the muffle furnace after calcining, putting into air for cooling, and grinding to a particle size of less than 0.075mm after cooling to room temperature; for sintering red mud, grinding the red mud to a particle size of less than 0.15mm.
Weighing 2.85kg of gangue, 1.25kg of sintered red mud and 0.9kg of slaked lime, putting into a stirring container, and dry-mixing and stirring uniformly to obtain a mixture. Adding the obtained mixture into granulating equipment, adjusting the water quantity for granulating, sieving the produced balls, and selecting balls with the diameter of 10-15 mm; and then aging the selected balls for 7 days and drying and dehydrating at 60 ℃ to obtain the cement-free high-strength baking-free lightweight aggregate.
The cement-free high-strength baking-free lightweight aggregate prepared in the embodiment is subjected to performance measurement of barrel pressure strength, bulk density and softening coefficient, and the result shows that the barrel pressure strength of the cement-free high-strength baking-free lightweight aggregate prepared in the embodiment is 7.5Mpa and the bulk density is 874kg/m 3 The softening coefficient was 0.85.
Example 4
As shown in fig. 1, coal gangue and sintered red mud are pretreated. Crushing coal gangue to a particle size of less than 4.75mm, placing crushed coal gangue particles into a muffle furnace, calcining at 700 ℃ for 6 hours, immediately taking out from the muffle furnace after calcining, cooling in air, cooling to room temperature, and grinding to a particle size of less than 0.075mm; and grinding the sintered red mud to a particle size of less than 0.15mm.
Weighing 3kg of gangue, 1.2kg of sintered red mud and 0.8kg of slaked lime, putting into a stirring container, and dry-mixing and stirring uniformly to obtain a mixture. Adding the obtained mixture into granulating equipment, adjusting the water quantity for granulating, sieving the produced balls, and selecting balls with the diameter of 10-15 mm; and then aging the selected balls for 8 days, and drying and dehydrating at 55 ℃ to obtain the cement-free high-strength baking-free lightweight aggregate.
The cement-free high-strength baking-free lightweight aggregate prepared in the embodiment is subjected to performance measurement of barrel pressure strength, bulk density and softening coefficient, and the result shows that the barrel pressure strength of the cement-free high-strength baking-free lightweight aggregate prepared in the embodiment is 7.1Mpa and the bulk density is 858kg/m 3 The softening coefficient was 0.85.
Example 5
As shown in fig. 1, coal gangue and sintered red mud are pretreated. Crushing coal gangue to a particle size of less than 4.75mm, putting crushed coal gangue particles into a muffle furnace, calcining at 680 ℃ for 6 hours, immediately taking out from the muffle furnace after calcining, putting into air for cooling, and grinding to a particle size of less than 0.075mm after cooling to room temperature; and grinding the sintered red mud to a particle size of less than 0.15mm.
Weighing 3kg of gangue, 1.25kg of sintered red mud and 0.75kg of slaked lime, putting into a stirring container, and dry-mixing and stirring uniformly to obtain a mixture. Adding the obtained mixture into granulating equipment, adjusting the water quantity for granulating, sieving the produced balls, and selecting balls with the diameter of 10-15 mm; and then aging the selected balls for 8 days and drying and dehydrating at 50 ℃ to obtain the cement-free high-strength baking-free lightweight aggregate.
The cement-free high-strength baking-free lightweight aggregate prepared in the embodiment is subjected to performance measurement of barrel pressure strength, bulk density and softening coefficient, and the result shows that the barrel pressure strength of the cement-free high-strength baking-free lightweight aggregate prepared in the embodiment is 6.8Mpa, and the bulk density is 863kg/m 3 The softening coefficient was 0.83.
Comparative example 1
The preparation process of comparative example 1 is basically the same as that of example 1, except that the amounts of coal gangue, red mud and slaked lime are 3.5Kg of coal gangue, 1.5Kg of sintered red mud and 0Kg of slaked lime. The final product has a barrel pressure of 1.2MPa and a bulk density of 826kg/m 3 The softening coefficient was 0.61.
Comparative example 2
The preparation process of comparative example 2 is basically the same as that of example 1, except that the amounts of coal gangue, red mud and slaked lime are 3.5kg of coal gangue, 1.25kg of sintered red mud and 0.25kg of slaked lime. The final product had a barrel pressure of 3.8MPa and a bulk density of 844kg/m 3 The softening coefficient was 0.73.
Comparative example 3
The preparation process of comparative example 3 is basically the same as that of example 1, except that the amounts of coal gangue, red mud and slaked lime are 3.25kg of coal gangue, 1.25kg of sintered red mud and 0.5kg of slaked lime. The final product had a barrel pressure of 5.6MPa and a bulk density of 842kg/m 3 The softening coefficient was 0.81.
Table 1 shows the performance data of the products prepared in examples 1 to 5 and comparative examples 1 to 3.
TABLE 1
As can be seen from the above, the cement-free high-strength baking-free lightweight aggregate prepared in examples 1-5 has a barrel pressure strength of 6.8-7.9 MPa and a bulk density of 858-880 kg/m 3 The softening coefficient is larger than 0.8, meets the requirement of high-strength lightweight aggregate in the standard GB/T17431.1-2010 of lightweight aggregate and test method 1 part thereof, can be used for building aggregate, and is green lightweight aggregate with development potential. The main raw materials of the embodiment 1-5, namely the coal gangue and the red mud, are solid wastes, the total consumption of the solid wastes is more than 80%, sintering and steam curing are not needed, the production cost is low, the preparation process is simple, the large-scale production is easy to realize, and the coal gangue and the red mud resource are realizedThe method has important significance.
Various modifications and variations of the present invention will be apparent to those skilled in the art in light of the foregoing teachings and are intended to be included within the scope of the following claims.
Claims (8)
1. The cement-free high-strength baking-free lightweight aggregate prepared from the coal gangue and the red mud is characterized by comprising, by weight, 55-60 parts of the coal gangue, 20-25 parts of the red mud and 15-20 parts of slaked lime.
2. The cement-free high-strength baking-free lightweight aggregate according to claim 1, wherein the red mud is sintered red mud, and the particle size of the red mud is less than 0.15mm.
3. The cement-free high-strength baking-free lightweight aggregate according to claim 1, wherein Ca (OH) in the slaked lime 2 The mass content of (2) is more than 90%.
4. The cement-free high-strength baking-free lightweight aggregate according to claim 1, wherein the coal gangue is crushed to a particle size of less than 4.75mm, then calcined in a muffle furnace at 680-750 ℃ for 6h, cooled and ground to a particle size of less than 0.075mm.
5. A method for preparing a cement-free high-strength baking-free lightweight aggregate by using coal gangue and red mud is characterized in that 55-60 parts of coal gangue, 20-25 parts of red mud and 15-20 parts of slaked lime are mixed to obtain a uniform mixture, the mixture is added into granulating equipment, water is added for granulating, and finally, balls are aged, dried and dehydrated to obtain the cement-free high-strength baking-free lightweight aggregate.
6. The method according to claim 5, wherein the gangue and the red mud are pretreated before mixing, wherein the gangue is crushed to a particle size of less than 4.75mm, the crushed gangue particles are put into a muffle furnace, calcined at 680-750 ℃ for 6 hours, immediately taken out of the muffle furnace after the calcination is completed, cooled in air, cooled to room temperature and ground to a particle size of less than 0.075mm; for red mud, grinding the red mud to a particle size of less than 0.15mm.
7. The method according to claim 5, wherein after granulation, the resulting pellets are first sieved, pellets having a diameter of 10 to 15mm are selected, and the selected pellets are aged and dried to remove water.
8. The method of claim 5, wherein the aging time is 6 to 8 days and the drying and dehydrating temperature is 80 ℃ or less.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311636501.4A CN117658570A (en) | 2023-12-01 | 2023-12-01 | Cement-free high-strength baking-free lightweight aggregate prepared from coal gangue and red mud and method |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311636501.4A CN117658570A (en) | 2023-12-01 | 2023-12-01 | Cement-free high-strength baking-free lightweight aggregate prepared from coal gangue and red mud and method |
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| CN117658570A true CN117658570A (en) | 2024-03-08 |
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|---|---|---|---|
| CN202311636501.4A Pending CN117658570A (en) | 2023-12-01 | 2023-12-01 | Cement-free high-strength baking-free lightweight aggregate prepared from coal gangue and red mud and method |
Country Status (1)
| Country | Link |
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| CN (1) | CN117658570A (en) |
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- 2023-12-01 CN CN202311636501.4A patent/CN117658570A/en active Pending
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