CN115819024A - Baking-free brick and preparation method thereof - Google Patents
Baking-free brick and preparation method thereof Download PDFInfo
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- CN115819024A CN115819024A CN202211614193.0A CN202211614193A CN115819024A CN 115819024 A CN115819024 A CN 115819024A CN 202211614193 A CN202211614193 A CN 202211614193A CN 115819024 A CN115819024 A CN 115819024A
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- GSEJCLTVZPLZKY-UHFFFAOYSA-N Triethanolamine Chemical compound OCCN(CCO)CCO GSEJCLTVZPLZKY-UHFFFAOYSA-N 0.000 claims description 5
- 238000004519 manufacturing process Methods 0.000 claims description 5
- 238000011068 loading method Methods 0.000 claims description 3
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- 238000005303 weighing Methods 0.000 claims description 3
- 230000002829 reductive effect Effects 0.000 abstract description 16
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- 238000006703 hydration reaction Methods 0.000 description 21
- 230000009286 beneficial effect Effects 0.000 description 18
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- 239000000292 calcium oxide Substances 0.000 description 15
- ODINCKMPIJJUCX-UHFFFAOYSA-N calcium oxide Inorganic materials [Ca]=O ODINCKMPIJJUCX-UHFFFAOYSA-N 0.000 description 15
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- AXCZMVOFGPJBDE-UHFFFAOYSA-L calcium dihydroxide Chemical compound [OH-].[OH-].[Ca+2] AXCZMVOFGPJBDE-UHFFFAOYSA-L 0.000 description 2
- 239000000920 calcium hydroxide Substances 0.000 description 2
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- BPQQTUXANYXVAA-UHFFFAOYSA-N Orthosilicate Chemical compound [O-][Si]([O-])([O-])[O-] BPQQTUXANYXVAA-UHFFFAOYSA-N 0.000 description 1
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- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 1
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- HNPSIPDUKPIQMN-UHFFFAOYSA-N dioxosilane;oxo(oxoalumanyloxy)alumane Chemical compound O=[Si]=O.O=[Al]O[Al]=O HNPSIPDUKPIQMN-UHFFFAOYSA-N 0.000 description 1
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- 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
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- Curing Cements, Concrete, And Artificial Stone (AREA)
Abstract
The invention discloses a baking-free brick, which comprises the following raw materials: the material comprises gasified slag, cement, red mud, fly ash, slag, desulfurized ash and grinding aids, wherein the mass ratio of the grinding aids is 2-4 per mill of the total mass of the gasified slag, the cement, the red mud, the fly ash, the slag and the desulfurized ash; the mass ratio of the gasified slag, the cement, the red mud, the fly ash, the slag and the desulfurized fly ash is (50-70%) (5-10%) (4-20%) (5-30%) (5-20%) (4-6%). The invention can successfully prepare the baking-free brick which meets the MU15 strength standard in GB/T21144-2007 concrete solid brick; the obtained baking-free brick has the advantages that the proportion of the gasified slag is higher than 50%, other industrial solid wastes are used for replacing part of cement, so that the mass proportion of the cement is controlled to be lower than 10%, and the cost of the baking-free brick is reduced.
Description
Technical Field
The invention relates to the technical field of building materials, in particular to a baking-free brick and a preparation method thereof.
Background
With the large-scale popularization of the coal gasification technology, the stock quantity and the production quantity of gasified slag are larger and larger, so that serious environmental pollution and land resource waste are caused, the sustainable development of coal chemical enterprises is adversely affected, the harmless and resource utilization of the gasified slag is urgent, and the application of the gasified slag to construction materials is an important way for large-scale consumption of the gasified slag.
At present, researchers prepare the baking-free bricks by using the gasified slag, but the prepared baking-free bricks have poor strength and durability, because the gasified slag contains a large amount of residual carbon and has strong adsorbability, a layer of hydrophobic film is formed on the surface of particles, the growth of hydrate gel and crystals is inhibited, the internal structure is damaged, and the strength and the durability of the product are influenced; and the residual carbon in the gasified slag limits the addition amount of the gasified slag in the baking-free brick, so that the mass ratio of the gasified slag in the baking-free brick is generally lower than 30 percent. Therefore, researchers add cement and a small amount of other industrial solid wastes (such as fly ash) to match in the process of preparing the baking-free brick, so that the strength of the baking-free brick is improved, but cement with the mass ratio of more than 15% can not only cause high hydration heat value, but also cause cracks to occur in the baking-free brick, and the cost of the baking-free brick is increased; in addition, the mass ratio of the fly ash in the baking-free brick is generally not higher than 10%, and the mass ratio of the fly ash in the baking-free brick is more than 10%, so that the strength of the baking-free brick is reduced, the resource utilization of solid wastes is limited, and the manufacturing cost of the baking-free brick is increased. Therefore, on the basis of ensuring the strength of the baking-free brick, the problems to be solved at present are how to increase the mass ratio of the gasified slag to the baking-free brick, reduce the mass ratio of the cement and increase the consumption of other industrial solid wastes, thereby achieving the utilization of the gasified slag and the industrial solid wastes and also reducing the cost of the baking-free brick.
Disclosure of Invention
Aiming at the problems in the prior art, the invention discloses a baking-free brick and a preparation method thereof, and gasification slag contains a large amount of amorphous Al due to high content 2 O 3 And SiO 2 The glass phase has potential gel activity, and a large amount of gasified slag in the environment is not beneficial to the environment, so that the unfired brick is prepared from the gasified slag, the influence of the gasified slag on the environment is reduced, and the potential gel activity of the gasified slag can be exerted. However, the strength and the frost resistance of the baking-free brick prepared by using the gasified slag are poor due to the fact that the gasified slag contains residual carbon, so that the adding quality of the baking-free brick is limited; the prior art has the problem that the strength of the baking-free brick is weakened due to gasification slag through a large amount of cement, but the addition of excessive cement not only increases the production cost, but also causes the cement to have higher hydration heat value and also causes cracks to be formed on the surface of the baking-free brick. Therefore, on the basis of ensuring that the obtained baking-free bricks meet the MU15 strength standard in GB/T21144-2007 concrete solid bricks, the invention can further reduce the mass ratio of cement to be less than 15% and improve the mass ratio of fly ash and other industrial solid wastes while improving the mass ratio of gasified slag to be more than 50%.
The invention is realized by the following technical scheme:
the invention provides a baking-free brick which comprises the following raw materials: the grinding aid comprises gasified slag, cement, red mud, fly ash, slag, desulfurized fly ash and a grinding aid, wherein the mass ratio of the grinding aid is 2-4 per mill of the total mass of the gasified slag, the cement, the red mud, the fly ash, the slag and the desulfurized fly ash; the weight ratio of the gasified slag, the cement, the red mud, the fly ash, the slag and the desulfurized fly ash is (50% -70%) (5% -10%) (4% -20%) (5% -30%) (5% -20%) (4% -6%).
According to the design of the invention, the gasified slag contains a large amount of amorphous Al 2 O 3 And SiO 2 The glass phase has potential gelling activity and is beneficial to improving the strength of the baking-free brick; the red mud has the characteristics of loam, and has the characteristics of low water absorption, heat insulation, freezing resistance and corrosion resistance; the chemical components of the fly ash are similar to those of clay, the chemical property is stable, and the hydration reaction speed can be promoted; the silicon dioxide and the alumina in the slag can generate a melt which takes silicate and aluminosilicate as main components and generate a secondary hydration reaction with hydration product calcium hydroxide, thereby promoting the generation of more C-S-H gel and being beneficial to improving the strength of the baking-free brick; the desulfurized fly ash can reduce the hydration heat, and is favorable for overcoming the shrinkage of the baking-free brick and the formation of a temperature difference heat seam caused by the hydration temperature; the cement can be hardened in air or water, so that the strength of the baking-free brick is improved, and the erosion resistance of the baking-free brick to fresh water and salt water can be improved. Although the gasified slag has potential gelling activity, the gasified slag can be activated to play a role, and the red mud contains a large amount of chemical alkali which can provide an alkaline environment and promote Al 2 O 3 And SiO 2 Depolymerisation to H 3 SiO 4- And H 3 AlO 4 2- With Ca in the hydrated slurry 2+ 、OH - Generating hydration reaction to generate C-S-H gel and C-A-S-H gel; although cement can obviously improve the strength of the baking-free brick, the cement can possibly cause temperature difference heat seams of the baking-free brick due to high hydration heat value, and the desulfurized ash can reduce the hydration heat, but when the addition amount of the cement is too high, the function of the desulfurized ash has certain limitation; the fly ash and the slag can partially replace cement, the chemical components of the fly ash are similar to those of clay, the fly ash can partially replace cement, the crack occurrence rate of a product is reduced, and the consumption of calcium hydroxide in hydrate can be consumed, so that the hydration heat is reduced; although the gelatinization of the slag is not good as that of cement, the slag can play a role in a microcrystalline nuclear effect, accelerate the hydration reaction of the cement, provide a sufficient space for hydration products, ensure that the distribution of the hydration products is more uniform and is beneficial to improving the compactness and the mechanical property of the products; and the dense filling structure formed by the slag can reduce the standard thicknessThe water consumption under the degree can improve the fluidity of the mixture under the condition of keeping the same water consumption, can also increase the cohesiveness of the mixture and prevent bleeding segregation. When the gasification slag is subjected to physical excitation of gel activity, the grinding aid is added, so that full contact between the gasification slag and other substances is facilitated, the reaction rate is increased, and the strength of the baking-free brick is facilitated to be improved. The baking-free brick obtained by the invention meets the MU15 strength standard in GB/T21144-2007 concrete solid bricks of the baking-free brick, simultaneously, the mass ratio of the gasified slag is over 50 percent, the mass ratio of the cement is reduced to be below 10 percent, and the mass ratio of industrial solid wastes such as fly ash and the like is improved, thereby realizing the reutilization of the gasified slag and the industrial solid wastes and reducing the production cost of the baking-free brick.
As a further scheme, the gasified slag comprises 20-30 wt.% of CaO; the red mud comprises 15-20 wt.% CaO and 10-15 wt.% Na 2 O、20wt.％-30wt.％SiO 2 、27wt.％-33wt.％Al 2 O 3 (ii) a The fly ash comprises 45-55 wt.% SiO 2 、35wt.％-42wt.％Al 2 O 3 (ii) a The slag comprises 36-42 wt.% CaO, 8-11 wt.% MgO; the desulfurized fly ash comprises 33-37 wt.% CaO and 10-13 wt.% SO 3 (ii) a The cement comprises 60-70 wt.% CaO and 15-23 SiO 2 、3wt.％-5wt.％Al 2 O 3 (ii) a The gasified slag, the slag and the desulfurized ash comprise 13-16 wt.% of Al 2 O 3 、SiO 2 Mass ratio of (3) to Al 2 O 3 The mass ratio of (1.9-2.5) to (1). The gasified slag, the fly ash and the desulfurized fly ash in the invention need to meet SiO 2 And Al 2 O 3 The mass ratio of (1.9-2.5) to 1 is satisfied, which is beneficial to activating potential gel activity with CaO provided in cement under the alkaline environment provided by red mud, thereby promoting to form se:Sub>A reticular structure in baking-free, realizing consolidation of heavy metal ions, and generating C-S-H gel and C-A-S-H gel through hydration reaction, thereby realizing the enhancement of the strength of the baking-free brick; the desulfurized fly ash is high-calcium low-sulfur desulfurized fly ash, and the slag also contains rich CaO and fly ashHas rich SiO 2 And Al 2 O 3 Can be used as CaO and SiO 2 And Al 2 O 3 The supplement agent is beneficial to improving the strength of the baking-free brick, high-content MgO in slag can be combined with CaO to improve the potential activity of gel, and the MgO not only has alkalinity and can provide a certain alkaline environment, but also is beneficial to adsorbing heavy metals. The cement is P.I type benchmark cement.
As a further scheme, the baking-free brick comprises the following raw materials: the grinding aid comprises gasified slag, cement, red mud, fly ash, slag, desulfurized fly ash and a grinding aid, wherein the mass ratio of the grinding aid is 2-4 per mill of the total mass of the gasified slag, the cement, the red mud, the fly ash, the slag and the desulfurized fly ash; the weight ratio of the gasified slag, the cement, the red mud, the fly ash, the slag and the desulfurized fly ash is (50-60%), (5-8%), (15-25%), (15-20%), (4-6%), and the weight ratio of the cement to the fly ash is 1 (3-5). Under the mass ratio, the strength of the baking-free brick meets the MU20 strength standard in GB/T21144-2007 concrete solid bricks, and the mass percentage of the solid waste content in the baking-free brick can be further increased to be higher than 15%.
As a further approach, the grinding aid comprises triethanolamine.
According to a further scheme, the preparation method of the baking-free brick comprises the steps of grinding cement and gasified slag by using a grinding aid, weighing the cement, the red mud, the fly ash, the slag and the desulfurized ash according to the mass ratio, mixing the cement, the red mud, the fly ash, the slag and water to obtain slurry, stirring, slowly rotating for the first time, adding the gasified slag, continuously slowly rotating for the second time to mix the gasified slag into the slurry, uniformly stirring the materials by fast rotation, placing the uniformly mixed slurry into a container, forming under certain pressure, fixing the load, demolding and maintaining to obtain the baking-free brick.
As a further proposal, the specific surface areas of the ground cement and the gasified slag after being respectively not less than 360m 2 /kg and not less than 400m 2 /kg。
As a further scheme, the time of the first slow rotation stirring is 25s-35s, and the rotating speed of the first slow rotation is (140 +/-5) r/min; the time for mixing the gasified slag into the slurry by the second slow rotation is 55s-65s, and the speed of the second slow rotation is (140 +/-5) r/min; the fast rotation time is 115s-125s, and the fast rotation speed is (285 +/-10) r/min.
As a further scheme, when the slurry is put into the container, the container needs to be placed on a vibration table with the vibration frequency of 40Hz-60Hz for filling.
As a further scheme, the pressure is 5MPa-15MPa, and the loading time is 20s-30s.
As a further scheme, the curing time is 28 days, the curing humidity is 95% +/-2%, and the temperature is 20 +/-0.5 ℃.
The invention has the characteristics and beneficial effects that:
(1) The invention can successfully prepare the baking-free brick which meets the MU15 strength standard in GB/T21144-2007 concrete solid bricks.
(2) Can solve the problems of environmental pollution and land occupation of the gasified slag.
(3) The invention promotes the formation of gel by physical excitation and chemical excitation methods, so that a network structure is formed in the hydration process, and heavy metal ions are consolidated, thereby realizing the harmless and resource utilization of various solid wastes.
(4) The baking-free brick successfully obtained by the invention improves the mass ratio of the gasified slag to make the mass ratio of the gasified slag higher than 50%, and replaces part of cement with other industrial solid wastes, so that the mass ratio of the cement is controlled to be lower than 10%, thereby reducing the hydration heat brought by the cement and simultaneously reducing the cost of the baking-free brick.
(5) According to the invention, the hydration heat value of the baking-free brick is reduced and the strength and frost resistance of the baking-free brick are enhanced by controlling the mass ratio of the substances.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some drawings of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on the drawings without creative efforts.
FIG. 1 shows the phenomena of the surface efflorescence caused by desulfurized fly ash in the examples.
FIG. 2 shows the phenomena of surface efflorescence of test blocks with different amounts of desulfurized fly ash.
FIG. 3 is a composition XRD pattern of the crystalline substance.
FIG. 4 shows the trend of mass loss with increasing number of freeze-thaw cycles for the examples.
Detailed Description
In order to facilitate understanding of the non-burnt brick of the present invention, the following more complete description of the method for preparing the non-burnt brick of the present invention is given by way of example, without thereby limiting the scope of the present invention.
(1) The preparation process comprises the following steps: grinding cement and gasified slag by using a grinding aid, wherein the specific surface areas of the ground cement and the gasified slag are respectively not less than 360m 2 /kg and not less than 400m 2 In terms of/kg. Respectively weighing cement, red mud, fly ash, slag and desulfurized fly ash according to the mass ratio, mixing the cement, the red mud, the fly ash, the slag and water, putting the mixture into a stirrer for stirring, slowly rotating for 30s for the first time, and adding gasified slag, wherein the rotating speed of the slow rotation for the first time is (140 +/-5) r/min; continuing to slowly rotate for 1min for the second time to mix the gasified slag into the slurry, wherein the speed of the slow rotation for the second time is (140 +/-5) r/min; rotating for 1min to stir the slurry uniformly, scraping the slurry on the wall of the container, and continuously rotating for 1min at the rotating speed of (285 +/-10) r/min; placing the uniformly mixed slurry into a container of 240mm multiplied by 115mm multiplied by 53mm, filling on a vibration table with vibration frequency of 50Hz, molding under the pressure of 5-15Mpa after filling, fixing the load for 25s, demolding, and curing for 28 days to obtain the baking-free brick, wherein the curing humidity is 95% +/-2%, and the curing temperature is 20 +/-0.5 ℃.
(2) The strength of the baking-free brick is tested, and the testing process comprises the following steps: the compressive strength of the steel plate was measured by using a servo press, and the load application rate was 2.4KN/s.
(3) In the present invention, the composition table of each substance is shown in table 1:
TABLE 1 raw material composition in baking-free brick
Analysis of verification results
TABLE 2 influence of Red mud, fly ash, slag and desulfurized fly ash on the strength of baking-free bricks respectively
Note: the addition amount of triethanolamine is 3 per mill of the total mass of the gasified slag, the cement, the red mud, the fly ash, the slag and the desulfurized fly ash.
On the premise of obtaining the baking-free bricks meeting the standard, the mass ratio of the gasified slag in the baking-free bricks is promoted to exceed 50%, the mass ratio of the cement is reduced to be lower than 15%, the mass ratio of other industrial solid wastes is increased, and the problems of cost and cracking on the surfaces of the baking-free bricks due to too much mass ratio of the cement are solved while the industrial solid wastes are solved.
We first investigated the effect of a single factor on the strength of a baking-free brick, instead of the amount of cement, as shown in examples 1-17. The red mud has high content of chemical alkali Na 2 O (13.43%), the alkaline environment is favorable for activating the gelling activity of the gasified slag, and as shown in examples 1-5, we have found that, within a certain range, the red mud replaces part of the cement, i.e. the mass percentage of the red mud is 10%, the 28-day strength of the baking-free brick can be improved (as in example 2), but the mass percentage of the red mud higher than 20% reduces the strength of the baking-free brick, and therefore, we select the mass percentage of the red mud lower than 10%.
We further investigated the replacement of part of the cement with fly ash, as in example 1 and examples 6-9Shown in the figure. When the fly ash replaces part of cement and the mass percentage is higher than 10%, the 3-day strength and the 28-day strength of the baking-free brick show a descending trend. It is considered that the reason is probably that the fly ash has the property of clay, which is beneficial to the bonding between substances, but the dispersion uniformity between the substances is influenced as the fly ash is increased; moreover, the formation of gel is influenced by the increase of the proportion of the cement replaced by the fly ash, the CaO in the fly ash is only (2.29 percent), the CaO in the cement is only (65.58 percent), and sufficient Ca cannot be provided in the process of forming gel 2+ And thus limited gel is formed, resulting in a decrease in strength of the non-burnt brick, and thus, when the mass of the fly ash is more than 10%, the strength of the non-burnt brick is decreased, and generally, the mass of the fly ash in the non-burnt brick is not more than 10%.
We have also investigated the effect of slag substitution on the strength of the non-fired brick, as shown in examples 1 and 10-13. We found that when the mass proportion of slag is not more than 20%, as in example 10 to example 11, the 3-day strength and the 28-day strength of the baking-free brick are superior to those of example 1, but as the mass proportion of slag in place of cement increases, the 28-day strength of the baking-free brick starts to decrease. It is believed that the slag has a high mass ratio of CaO (39.98%) and SiO 2 (29.37%) can partially replace the dosage of cement, and slag can be filled in pores to form a compact filling structure and a self-compact stacking system; and the slag can improve the fluidity of the mixture, is beneficial to increasing the cohesiveness of the mixture and preventing bleeding segregation, thereby being beneficial to improving the strength of the baking-free brick, which may be the reason for higher forming capability of the baking-free brick in the early stage. Therefore, the mass proportion of the slag in the baking-free brick is controlled not to be higher than 20% preliminarily.
We have further investigated the variation in strength of the non-fired bricks after the desulfurized fly ash has replaced a portion of the cement, as shown in example 1 and examples 14-17. The use of desulfurized fly ash in place of cement in non-fired bricks can be detrimental to the early stage of forming and 28-day strength of non-fired bricks, as shown in examples 1 and 14. Although the 28-day strength of the baking-free bricks increases with the increase in the replacement mass of the desulfurized fly ash, the baking-free bricks are left in 3 daysThe intensity instead decreased as shown in example 14-example 28. It is considered possible that the desulfurized fly ash contains a large amount of CaO in free form (65.58%), and when incorporated in excess, the free calcium oxide reacts with water to form Ca (OH) 2 Can diffuse to the surface of the baking-free brick through the test block gap in the early maintenance stage, and Ca (OH) on the surface of the baking-free brick and in the gap is generated at the moment 2 With CO 2 React to form CaCO 3 The test block is cracked; and the addition amount of the desulfurized fly ash is too much, so that the efflorescence phenomenon also occurs on the surface of the baking-free brick, as shown in figure 1.
To this end, we further investigated the minimum amount of the blend of the desulfurized fly ash to cause the saltpetering, as shown in examples 18 to 21, and found that the saltpetering phenomenon is conspicuous on the surface of the baking-free bricks when the blend of the desulfurized fly ash exceeds 6% as shown in FIG. 2, and we analyzed the saltpetering mineral phase, and found that the saltpetering component is mainly CaCO as shown in FIG. 3 3 Therefore, the guess of the people is verified, because the content of free CaO in the desulfurized fly ash is too much, the weight percentage of the desulfurized fly ash in the baking-free brick is controlled to be 4-6%.
Because the mass ratio of the cement not only influences the high hydration heat value, but also causes cracks on the surface of the baking-free brick and increases the cost, the mass ratio of the cement in the baking-free brick is reduced while more gasified slag and industrial solid waste are used on the basis of obtaining the baking-free brick meeting the strength standard. Therefore, the gasified slag with the mass ratio of 50% and the cement with the mass ratio of 10% are selected for further research. We further investigated the interaction between industrial solid wastes to replace the amount of cement in baking-free bricks as shown in examples 22-30. The red mud has higher alkalinity, is beneficial to activating the gel activity of the gasified slag, thereby being beneficial to promoting the generation of gel and improving the strength of the baking-free brick. As shown in examples 22-24 and 28-30, we have found that when the mass of the red mud is 20% and the mass of the fly ash or slag is 20% (i.e., 20% of the cement is replaced by fly ash or slag), the 28-day strength of the baking-free brick obtained is optimal, and we have further found that slag-substituted cement is superior to fly ash-substituted cement; and the 3-day strength of the baking-free brick is obviously reduced along with the increase of the fly ash, and the fly ash is not beneficial to the early-stage forming of the baking-free brick. The mass ratio of the red mud is not higher than 20%, and the mass ratio of the fly ash to the slag is not higher than 20%. It can also be confirmed from example 25 to example 27 that the 3-day strength and the 28-day strength of the baking-free bricks are reduced when the ratio of the mass of the slag is lower than that of the pulverized coal slag.
On the basis, the use of the fly ash, the slag and the red mud to replace the cement with the mass ratio of 40% is further researched, as shown in examples 31-33, the fly ash and the slag replace part of the cement under a certain alkaline environment, so that the baking-free brick with excellent strength for 3 days and 28 days can be obtained, and the mass ratio of the slag is not less than that of the pulverized coal slag, so that the strength of the baking-free brick is improved.
The desulfurized ash can be used as a calcium supplement material, also has the function of reducing the hydration heat, can overcome the shrinkage of the baking-free brick, and is favorable for reducing the cracks of the baking-free brick caused by too high hydration heat. We further investigated the effect of adding desulfurized fly ash on the strength of a baking-free brick, together with red mud, fly ash and slag, to replace a portion of the cement, as shown in examples 34-42. The 28-day strength of the baking-free bricks obtained in examples 34 and 42 all meet the MU15 strength standard in GB/T21144-2007 concrete solid bricks, and the 28-day strength of the baking-free bricks in examples 36, 38, 39 and 42 all meet the MU25 strength standard in GB/T21144-2007 concrete solid bricks. Therefore, through the mutual matching of the substances, the red mud, the fly ash, the slag and the desulfurized fly ash successfully replace most of cement, the mass proportion of the gasified slag is increased to 50%, and the mass proportion of the cement is reduced to 10%.
On the basis, the matching effect of the substances is further researched, and the effect of the fly ash on the strength of the baking-free brick is found in the previous examples, so that when a small amount of fly ash is added, the fly ash can replace part of the cement and is beneficial to the strength of the baking-free brick, as shown in examples 36 and 39, the mass proportion of the fly ash in the baking-free brick is only 5%; when the mass proportion of the fly ash is 20%, as shown in examples 40 and 41, although the mass of the baking-free brick is reduced compared with examples 36 and 39, the 28-day strength of the baking-free brick still meets the MU20 strength standard in GB/T21144-2007 concrete solid brick, and further comparison of examples 41 and 45 shows that when the mass proportion of the fly ash is increased, both 20%, the strength of the baking-free brick of example 45 is significantly reduced, and we find that the mass proportion of the cement of the baking-free brick of example 41 is 10%, and the mass proportion of the cement of example 45 is 5%, so that increasing the amount of the cement can compensate for the adverse factor of the reduction in strength of the baking-free brick caused by the large mass proportion of the fly ash; we further compare example 41 with example 37 to find that in example 37, the ratio of slag is 20% by mass and the ratio of fly ash is 10% by mass, but the 28-day strength of the baking-free brick of example 37 is lower than that of example 41, which is considered to be probably because increasing the ratio of red mud is beneficial to increasing the ratio of fly ash, and we can also verify by comparing example 37 with example 42. In the non-burnt brick, the mass proportion of the cement has the greatest influence on the strength of the non-burnt brick, as found by comparing example 43 with example 35; further, slag can compensate for the problem of strength reduction due to the reduction in cement ratio, as shown in example 44. In conclusion, in the formula with the gasified slag more than 50%, when the proportion of cement or red mud is not less than 10%, the mass proportion of the fly ash in the baking-free brick can reach 20%, and the strength of the baking-free brick can meet the MU15 strength standard and can partially meet the MU 20-MU 25 strength standard; however, when the proportion of the cement or the red mud is further reduced to be less than 10%, the strength of the baking-free brick does not meet the MU15 strength standard, and most of the baking-free brick cannot meet the MU20 strength standard.
Besides chemical activation, physical activation can also be used to make the specific surface area of the reference cement be more than 360m 2 Per kg, grinding the specific surface area of the gasified slag to 400m 2 More than kg, on one hand, the lattice structure is damaged, and the reaction capacity is increased; on the other hand, mixing it with cementFully contacting to increase the reaction efficiency. The mass ratio of the grinding aid triethanolamine to the total mass of the gasified slag, the cement, the red mud, the fly ash, the slag and the desulfurized ash is 3 per mill, and in the case of the examples 38, 41 and 42, the same mass of triethanolamine is added, so that as shown in the examples 46 to 48, the 28-day strength of the examples 46 to 48 is improved by 5Mpa on average. The tests for freezing resistance of examples 46-48 were also performed and as shown in fig. 4, we found that the quality of the baking-free bricks remained small with increasing freeze-thaw times, and that the strength of the overall durability group was small with increasing freeze-thaw times, although the strength of the examples was slightly lower than day 0.
Based on the above, we found that the grinding aid can be beneficial to further reduce the mass ratio of the cement and further increase the mass ratio of the fly ash, as in example 37, compared with example 49 and example 40, compared with example 51, the mass ratio of the cement in the baking-free brick is reduced to 5%, and the 28-day strength of the baking-free brick is enhanced; we further found that the grinding aid can also reduce the mass ratio of cement to red mud and increase the mass ratio of fly ash, as shown in example 38 compared to example 50 and example 42 compared to example 51, we believe that the potential activity of the gel is stimulated by physical means, which compensates for the strength reduction caused by fly ash and also reduces the mass ratio of cement to red mud. After the grinding aid is added, on the basis that the mass ratio of the gasified slag is 50%, the mass ratio of the cement can be less than 10%, the mass ratio of the red mud is less than 10%, and the mass ratio of the fly ash can be higher than 15%. On the basis, whether the grinding aid is added is beneficial to further increasing the mass ratio of the gasified slag, and as shown in examples 52 to 63, the 28-day strength of the baking-free brick meets the MU15 strength standard in GB/T21144-2007 concrete solid bricks. We find that, although the mass percentage of the red mud is 0%, the grinding aid is in favor of improving the reaction between the gasified slag and other substances through a physical activation mode, so that the utilization rate of the gasified slag is improved, the mass percentage of the gasified slag in the baking-free brick is increased, the mass percentage of the red mud is increased to 70% from 50%, and the mass percentage of the cement and the fly ash is from 1 (0.5-2) at first, after the grinding aid is added, the mass percentage of the cement and the mass percentage of the fly ash are about 1 (3-5), so that the grinding aid is in favor of ensuring that the mass percentage of the gasified slag in the baking-free brick exceeds 50%, simultaneously promoting the mass percentage of the cement to be lower than 10% and the mass percentage of the fly ash to be higher than 15%, and simultaneously the 28-day strength of the baking-free brick meets the MU20 strength standard in GB/T21144-2007 solid concrete brick.
In conclusion, the grinding aid is further selected to be added by 2-4 per mill of the total mass of the gasified slag, the cement, the red mud, the fly ash, the slag and the desulfurized fly ash, the mass ratio of the gasified slag, the cement, the red mud, the fly ash, the slag and the desulfurized fly ash is (50-70%) (5-10%) (4-20%) (5-30%) (5-20%) (4-6%), and at the moment, the 28-day strength of the obtained baking-free brick meets the MU15 strength standard in GB/T21144-2007 concrete solid brick. On the basis, the addition mass of the grinding aid is 2-4 per mill of the total mass of the gasified slag, the cement, the red mud, the fly ash, the slag and the desulfurization ash, the mass ratio of the gasified slag, the cement, the red mud, the fly ash, the slag and the desulfurization ash is (50-60%) (5-8%) (15-25%) (15-20%) (4-6%) and the mass ratio of the cement to the fly ash is 1 (3-5), and at the moment, the 28-day strength of the obtained baking-free brick meets the MU20 strength standard in GB/T21144-2007 concrete solid bricks.
It should be noted that the above-mentioned embodiments are only preferred embodiments of the present invention, and the present invention is not limited thereto, and any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (10)
1. The baking-free brick is characterized by comprising the following raw materials: the material comprises gasified slag, cement, red mud, fly ash, slag, desulfurized ash and grinding aids, wherein the mass ratio of the grinding aids is 2-4 per mill of the total mass of the gasified slag, the cement, the red mud, the fly ash, the slag and the desulfurized ash; the mass ratio of the gasified slag, the cement, the red mud, the fly ash, the slag and the desulfurized fly ash is (50-70%) (5-10%) (4-20%) (5-30%) (5-20%) (4-6%).
2. The baking-free brick as claimed in claim 1, wherein the gasified slag comprises 20-30 wt.% CaO; the red mud comprises 15-20 wt.% CaO and 10-15 wt.% Na 2 O、20wt.％-30wt.％SiO 2 、27wt.％-33wt.％Al 2 O 3 (ii) a The fly ash comprises 45-55 wt.% SiO 2 、35wt.％-42wt.％Al 2 O 3 (ii) a The slag comprises 36-42 wt.% CaO, 8-11 wt.% MgO; the desulfurized fly ash comprises 33-37 wt.% CaO and 10-13 wt.% SO 3 (ii) a The cement comprises 60-70 wt.% CaO and 15-23 SiO 2 、3wt.％-5wt.％Al 2 O 3 (ii) a The gasified slag, the slag and the desulfurized ash comprise 13-16 wt.% of Al 2 O 3 、SiO 2 Mass ratio of (A) to Al 2 O 3 The mass ratio of (1.9-2.5) to (1).
3. The baking-free brick as claimed in claim 1, wherein the baking-free brick comprises the following raw materials: the grinding aid comprises gasified slag, cement, red mud, fly ash, slag, desulfurized fly ash and a grinding aid, wherein the mass ratio of the grinding aid is 2-4 per mill of the total mass of the gasified slag, the cement, the red mud, the fly ash, the slag and the desulfurized fly ash; the mass ratio of the gasified slag, the cement, the red mud, the fly ash, the slag and the desulfurized fly ash is (50-60%) (5-8%) (15-25%) (15-20%) (4-6%) by mass, and the mass ratio of the cement to the fly ash is 1 (3-5).
4. The baking-free brick as claimed in claim 1, wherein the grinding aid comprises triethanolamine.
5. The process for preparing a baking-free brick as claimed in any one of claims 1 to 4, which comprises grinding cement and gasified slag by using a grinding aid, weighing the cement, red mud, fly ash, slag and desulfurized ash respectively according to the mass ratio, mixing the weighed cement, red mud, fly ash, slag and desulfurized ash with water to obtain slurry, stirring, slowly rotating for the first time, then adding the gasified slag, continuously rotating for the second time to mix the gasified slag into the slurry, uniformly stirring the substances by fast rotation, placing the uniformly mixed slurry into a container, forming under a certain pressure, loading, demolding and curing to obtain the baking-free brick.
6. The method according to claim 5, wherein the specific surface areas of the ground cement and the gasified slag after grinding are not less than 360m 2 /kg and not less than 400m 2 /kg。
7. The preparation method of claim 5, wherein the first slow rotation stirring time is 25s-35s, the first slow rotation speed is (140 ± 5) r/min; the time for mixing the gasified slag into the slurry is 55s-65s through the second slow rotation, and the speed of the second slow rotation is (140 +/-5) r/min; the fast rotation time is 115s-125s, and the fast rotation speed is (285 +/-10) r/min.
8. The method of claim 5, wherein the slurry is placed in the container by filling the container on a vibrating table with a vibration frequency of 40Hz-60 Hz.
9. The method according to claim 5, wherein the pressure is 5MPa to 15MPa and the loading time is 20s to 30s.
10. The method according to claim 5, wherein the curing time is 28 days, the curing humidity is 95% ± 2% and the curing temperature is 20 ℃ ± 0.5 ℃.
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| CN116986829A (en) * | 2023-06-13 | 2023-11-03 | 中国地质大学（武汉） | Semi-dry desulfurization ash-fly ash-slag composite cementing material and preparation method thereof |
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| JP2019011214A (en) * | 2017-06-29 | 2019-01-24 | 太平洋セメント株式会社 | Cement additive and cement composition |
| CN113336516A (en) * | 2021-07-15 | 2021-09-03 | 内蒙古工业大学 | Cementing material prepared from multi-element solid wastes and cooperative regulation and control method thereof |
| CN114751692A (en) * | 2022-03-31 | 2022-07-15 | 国家能源集团宁夏煤业有限责任公司 | Gasification slag water permeable brick and preparation method thereof |
| CN115010441A (en) * | 2022-07-08 | 2022-09-06 | 河北涿州京源热电有限责任公司 | Baking-free brick slurry formula and preparation method of baking-free brick |
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| GB8918390D0 (en) * | 1988-08-12 | 1989-09-20 | Nat Res Dev | Cement compositions |
| JP2019011214A (en) * | 2017-06-29 | 2019-01-24 | 太平洋セメント株式会社 | Cement additive and cement composition |
| CN113336516A (en) * | 2021-07-15 | 2021-09-03 | 内蒙古工业大学 | Cementing material prepared from multi-element solid wastes and cooperative regulation and control method thereof |
| CN114751692A (en) * | 2022-03-31 | 2022-07-15 | 国家能源集团宁夏煤业有限责任公司 | Gasification slag water permeable brick and preparation method thereof |
| CN115010441A (en) * | 2022-07-08 | 2022-09-06 | 河北涿州京源热电有限责任公司 | Baking-free brick slurry formula and preparation method of baking-free brick |
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| CN116986829A (en) * | 2023-06-13 | 2023-11-03 | 中国地质大学（武汉） | Semi-dry desulfurization ash-fly ash-slag composite cementing material and preparation method thereof |
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