High-strength desulfurization ash-based cementing material as well as preparation method and application thereof

Abstract

The invention relates to the technical field of industrial solid waste resource utilization, in particular to a high-strength desulfurization ash-based cementing material as well as a preparation method and application thereof. The high-strength desulfurized fly ash-based cementing material is prepared from the following raw materials in parts by mass: 30-70 parts of desulfurized fly ash, 20-70 parts of fly ash, 0-30 parts of mineral powder, 0-10 parts of cement, 2-8 parts of an alkali activator, 1-4 parts of a water reducer and 20-35 parts of water. The high-strength desulfurization ash-based cementing material provided by the invention has high mechanical properties and good volume stability, shows excellent comprehensive properties, and can well meet the use requirements of the cementing material. In addition, the preparation method is simple to operate, the raw materials do not need to be crushed, ground, dried or calcined, the production cost can be remarkably reduced, meanwhile, carbon emission is reduced, and mass production can be achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of resource utilization of industrial solid wastes, and particularly to a high-strength desulfurized ash-based cementitious material, a preparation method thereof, and an application thereof. Background Art

[0002] SO2 in the flue gas discharged from coal-fired power plants is the main source of SO2 in the atmosphere and causes very serious pollution to the atmosphere. Therefore, most coal-fired power plants carry out desulfurization treatment on the flue gas before its discharge by installing flue gas desulfurization devices. At present, the flue gas desulfurization technologies adopted by coal-fired power plants are divided into three categories: semi-dry method, wet method, and dry method desulfurization. Among them, the semi-dry method flue gas desulfurization technology has developed the fastest in recent years and has the advantages of high desulfurization rate, simple desulfurization device, low process cost, and small floor area of the device, so it is widely used. However, a large amount of solid powder desulfurized ash will be generated during the desulfurization process of the semi-dry method flue gas desulfurization technology. The composition of the semi-dry method desulfurized ash is relatively complex, and the properties of calcium sulfite therein are extremely unstable. Most of the desulfurized ash is disposed of by landfill, and there is no mature comprehensive utilization method. However, with the economic development and the increasing demand for flue gas desulfurization technology in various industries, the output of desulfurized ash has increased sharply. The landfill of desulfurized ash has caused land consumption and waste of sulfur and calcium resources. Therefore, the resource recycling of desulfurized ash has become an urgent problem to be solved.

[0003] At present, some researchers have explored the use of desulfurized ash for preparing cementitious materials. However, the SO3 content in desulfurized ash is very high, and a large amount of needle-like products ettringite will be generated during the hydration reaction, resulting in the expansion of the volume of the hardened paste. In addition, the volume of the paste is also unstable when the calcium sulfite component in the desulfurized ash is slowly oxidized to calcium sulfate, which causes a very large obstacle to the resource recycling of desulfurized ash.

[0004] Therefore, the existing technologies still need to be improved and developed. Summary of the Invention

[0005] In view of the above deficiencies of the prior art, the purpose of the present invention is to provide a high-strength desulfurized ash-based cementitious material, a preparation method thereof, and an application thereof, aiming to solve the problem of unstable paste volume existing in the existing use of desulfurized ash for preparing cementitious materials.

[0006] The technical solution of the present invention is as follows:

[0007] In the first aspect of the present invention, there is provided a high-strength desulfurized ash-based cementitious material, which is prepared from the following raw materials in parts by mass: 30-70 parts of desulfurized ash, 20-70 parts of fly ash, 0-30 parts of mineral powder, 0-10 parts of cement, 2-8 parts of alkali activator, 1-4 parts of water reducer, and 20-35 parts of water.

[0008] Optionally, the high-strength desulfurized ash-based cementitious material is prepared from the following raw materials in parts by mass: 30 to 70 parts of desulfurized ash, 20 to 70 parts of fly ash, 5 to 30 parts of mineral powder, 5 to 10 parts of cement, 2 to 8 parts of alkali activator, 1 to 4 parts of water reducer, and 20 to 35 parts of water.

[0009] Optionally, the alkali activator is at least one of sodium silicate, sodium hydroxide, sodium carbonate, potassium hydroxide, and sodium sulfate.

[0010] Optionally, the alkali activator is sodium silicate with a modulus of 1 to 2.

[0011] Optionally, the water reducer is at least one of polycarboxylate water reducer, naphthalene-based water reducer, melamine water reducer, and sodium lignosulfonate.

[0012] In a second aspect of the present invention, there is provided a method for preparing the high-strength desulfurized ash-based cementitious material according to the present invention, which includes:

[0013] Step S1: Weigh each raw material according to the mass ratio and set aside;

[0014] Step S2: Dissolve the alkali activator in a part of water and age it to obtain an alkali activation solution;

[0015] Step S3: Mix and stir desulfurized ash, fly ash, mineral powder, cement, water reducer, and the remaining water, and then add the alkali activation solution and mix and stir to obtain a mixed slurry;

[0016] Step S4: Pour the mixed slurry into a mold and cure it to obtain the high-strength desulfurized ash-based cementitious material.

[0017] Optionally, in step S2, the mass of the part of water is 40% to 60% of the total mass of water, and the aging time is 24 to 36 h.

[0018] Optionally, step S3 specifically includes:

[0019] Mix and stir desulfurized ash, fly ash, mineral powder, and cement at a rotation speed of 40 to 60 r / min for 120 to 150 s, then add the remaining water to pre-wet the raw materials for 60 to 80 s, then add the water reducer and mix and stir for 20 to 40 s, and finally add the alkali activation solution and first mix and stir at a rotation speed of 40 to 60 r / min for 60 to 90 s, and then mix and stir at a rotation speed of 120 to 140 r / min for 60 to 80 s to obtain a uniform mixed slurry.

[0020] Optionally, in step S4, the curing conditions include: temperature is 18°C to 22°C, humidity is 94% to 96%, and time is 1 to 28 days.

[0021] In a third aspect of the present invention, there is provided an application of the high-strength desulfurized ash-based cementitious material described in the present invention in the preparation of concrete or masonry mortar.

[0022] Beneficial effects: The high-strength desulfurized ash-based cementitious material provided by the present invention has high mechanical properties and good volume stability, exhibits excellent comprehensive properties, and can well meet the usage requirements of cementitious materials. On the one hand, by utilizing the chemical composition complementary mechanism of various raw materials, the sulfate in desulfurized ash reacts with silica and alumina in fly ash and slag powder to generate more ettringite and calcium silicate hydration products, thereby making the paste stronger; the addition of water reducer can reduce the water consumption, increase the compactness of hydration products, and the strength is also improved; the alkali activator can activate the reaction activity of fly ash and slag powder, and can also provide a sufficient alkaline environment for the hydration of the paste, which is beneficial to accelerating the erosion of the reactant surface, enabling the raw materials to accelerate the release of substances participating in hydration, thereby accelerating the hydration reaction and promoting the increase of the compressive strength of the paste. On the other hand, by adjusting the raw material ratio, the calcium-silicon ratio is changed, which can also play a role in regulating the morphology of the hydration products ettringite and calcium silicate hydrate. The reduction of needle-like hydration products improves the volume stability of the paste. In addition, the preparation method of the present invention is simple in operation, and the raw materials do not need to go through processes such as crushing, grinding, drying or calcining, which can significantly reduce production costs while reducing carbon emissions and can achieve mass production. Specific embodiments

[0023] The present invention provides a high-strength desulfurized ash-based cementitious material, its preparation method and application. To make the purpose, technical solution and effects of the present invention clearer and more definite, the present invention is further described in detail below. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0024] An embodiment of the present invention provides a high-strength desulfurized ash-based cementitious material, which is prepared from the following raw materials in parts by mass: 30 to 70 parts of desulfurized ash, 20 to 70 parts of fly ash, 0 to 30 parts of slag powder, 0 to 10 parts of cement, 2 to 8 parts of alkali activator, 1 to 4 parts of water reducer, and 20 to 35 parts of water.

[0025] The high-strength desulfurized ash-based cementitious material prepared by using desulfurized ash, fly ash, mineral powder, cement, alkali activator, water reducer and water in the mass fraction ratio described in the embodiments of the present invention has high mechanical properties and good volume stability. On the one hand, by utilizing the chemical composition complementary mechanism of various raw materials, the sulfate in the desulfurized ash reacts with the silica and alumina in the fly ash and mineral powder to generate more ettringite and calcium silicate hydration products, thus making the paste stronger; the addition of the water reducer can reduce the water consumption, increase the compactness of the hydration products, and the strength is also improved; the alkali activator can activate the reaction activity of the fly ash and mineral powder, and can also provide a sufficient alkaline environment for the paste hydration, which is beneficial to accelerating the erosion of the reactant surface, enabling the raw materials to accelerate the release of substances participating in the hydration, thereby accelerating the hydration reaction and promoting the increase of the compressive strength of the paste. On the other hand, the contents of calcium oxide and silica in several raw materials are different, and the calcium-silicon ratio can be changed by changing the number of parts of the added raw materials. The size of the calcium-silicon ratio can also play a role in regulating the morphology of the hydration products ettringite and calcium silicate hydrate. The reduction of needle-like hydration products improves the volume stability of the paste. The volume stability of the cementitious material of the present invention meets the national standard requirements, opening up a new way for the utilization of desulfurized ash in cementitious materials.

[0026] In the embodiments of the present invention, the mass fraction ratios of the raw materials of each component are designed. Specifically, in terms of mass fraction, the raw materials of the high-strength desulfurized ash-based cementitious material include 30 to 70 parts of desulfurized ash. For example, it can be 30 parts, 35 parts, 40 parts, 45 parts, 50 parts, 55 parts, 60 parts, 65 parts, 70 parts. Using the desulfurized ash within the mass fraction range can provide sufficient raw material calcium sulfate for the hydration reaction and promote the progress of the hydration reaction. The raw materials also include 20 to 70 parts of fly ash. For example, it can be 20 parts, 25 parts, 30 parts, 35 parts, 40 parts, 45 parts, 50 parts, 55 parts, 60 parts, 65 parts, 70 parts. Using the fly ash within the mass fraction range can provide the silicon source required for the hydration reaction and promote the generation of more hydration products. The raw materials also include 0 to 30 parts of mineral powder. For example, it can be 5 parts, 15 parts, 20 parts, 25 parts, 30 parts. The role of the mineral powder within the mass fraction range is the same as that of fly ash. The raw materials also include 0 to 10 parts of cement. For example, it can be 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts. Using the cement within the mass fraction range can provide a sufficient alkaline environment for the reaction system, increase the pH, accelerate the erosion rate of the raw material surface, and thus promote the hydration reaction. The raw materials also include 2 to 8 parts of alkali activator. For example, it can be 2 parts, 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts. Using the alkali activator within the mass fraction range can rapidly increase the pH in the reaction system. The raw materials also include 1 to 4 parts of water reducer. For example, it can be 1 part, 2 parts, 3 parts, 4 parts. Using the water reducer within the mass fraction range can reduce the water consumption in the reaction system, make the overall structure of the hydration products more compact, and improve the strength performance of the cementitious material. The high-strength desulfurized ash-based cementitious material prepared by the embodiments of the present invention using the mass fraction ratios of the above raw materials has high mechanical properties and good volume stability.

[0027] Compared with the existing desulfurized ash-based cementitious materials, the technical advantages of the high-strength desulfurized ash-based cementitious material of the embodiments of the present invention at least include:

[0028] (1) The high-strength desulfurized ash-based cementitious material has high mechanical properties and good volume stability. The highest strength of the tested material is 90.8 MPa, and the volume stability also meets the national standard requirements. Whether it is used to prepare high-strength concrete or masonry mortar in the later stage, it has strength and stability support, and has a wide application range, opening up a new way for the utilization of desulfurized ash in cementitious materials.

[0029] (2) The raw materials used do not need to go through processes such as crushing, grinding, drying, or calcination, which can significantly reduce production costs and carbon emissions while accelerating the production rhythm.

[0030] (3) During the preparation process, the cement content is very small (at most 10%), which can reduce costs and save energy. Moreover, the desulfurized ash contains calcium sulfate required for the hydration product calcium silicate hydrate, and both fly ash and mineral powder are rich in silicon dioxide. When the raw materials are incorporated simultaneously, their chemical components are complementary, which enables the existence of a synergistic mechanism in the reaction system and promotes the hydration reaction. In addition, the incorporation of cement can also provide an alkaline environment for the entire reaction system, enabling the cementitious material to have good workability and strength performance.

[0031] (4) The cementitious material only needs to be cured in a normal temperature curing box without high-temperature curing, and its hydration reaction can proceed smoothly. And when meeting the strength requirements of the cementitious material in construction projects, the dosage of desulfurized ash in the system can reach 60%, greatly improving the utilization rate of desulfurized ash resources.

[0032] In some embodiments, the high-strength desulfurized ash-based cementitious material is prepared from the following raw materials in parts by mass: 30 - 70 parts of desulfurized ash, 20 - 70 parts of fly ash, 5 - 30 parts of mineral powder, 5 - 10 parts of cement, 2 - 8 parts of alkali activator, 1 - 4 parts of water reducer, and 20 - 35 parts of water.

[0033] In some embodiments, the desulfurized ash is a solid waste generated from desulfurization in coal-fired power plants, and its chemical component CaO content is greater than 40%; the CaO content in the mineral powder is greater than 30%; the fly ash is Class II ash and complies with the GB1596 - 91 standard; the cement is P.O 42.5 cement and complies with the GB175 - 2007 General Portland Cement standard.

[0034] In some embodiments, the alkali activator is at least one of sodium silicate, sodium hydroxide, sodium carbonate, potassium hydroxide, and sodium sulfate. Preferably, the alkali activator is sodium silicate with a modulus of 1 - 2, such as sodium silicate with a modulus of 1, 1.5, or 2. According to previous research results, the optimal modulus of sodium silicate for the cementitious material is about 1.5. If the modulus of sodium silicate is too large, it is not sufficient to increase the pH of the reaction environment; but if the modulus is too small, it may cause the pH to be too high, resulting in flash setting of the paste.

[0035] In some embodiments, the water reducer is at least one of polycarboxylate water reducer, naphthalene-based water reducer, melamine water reducer, and sodium lignosulfonate.

[0036] The embodiment of the present invention provides a preparation method of the high-strength desulfurized ash-based cementitious material according to any one of the foregoing embodiments, which includes:

[0037] Step S1, weighing each raw material according to the mass ratio for standby;

[0038] Step S2: Dissolve the alkali activator in a portion of water and age it to obtain an alkali-activated solution.

[0039] Step S3: Mix and stir desulfurized ash, fly ash, slag powder, cement, water reducer and the remaining water, and then add the alkali-activated solution and mix and stir to obtain a mixed slurry.

[0040] Step S4: Pour the mixed slurry into a mold and cure it to obtain the high-strength desulfurized-ash-based cementitious material.

[0041] The preparation process of the high-strength desulfurized-ash-based cementitious material provided by the embodiment of the present invention is simple, can significantly reduce production costs while reducing carbon emissions, can achieve mass production, and the prepared high-strength desulfurized-ash-based cementitious material has high mechanical properties and good volume stability, showing excellent comprehensive performance and can well meet the usage requirements of cementitious materials.

[0042] In this embodiment, the alkali activator needs to be first dissolved in a portion of water and aged for a period of time to pre-prepare an alkali-activated solution to avoid affecting the temperature of the hydration reaction.

[0043] In this embodiment, using the standard consistency water consumption, the designed water incorporation amount is 20-35 parts, so that the slurry has good workability and rheology for construction operations.

[0044] In some embodiments, in step S2, the mass of the portion of water is 40%-60% of the total mass of water (for example, it can be 40%, 45%, 50%, 55%, 60%), and the aging time is 24-36 h (for example, it can be 24 h, 26 h, 28 h, 30 h, 32 h, 34 h, 36 h).

[0045] In some embodiments, step S2 specifically includes:

[0046] Dissolve the alkali activator in 40%-60% mass of water and age it at room temperature for 24-36 h to obtain an alkali-activated solution.

[0047] In some embodiments, step S3 specifically includes:

[0048] Mix and stir desulfurized ash, fly ash, slag powder and cement at a rotation speed of 40-60 r / min for 120-150 s, then add the remaining water to pre-wet the raw materials for 60-80 s, then add the water reducer and mix and stir for 20-40 s, and finally add the alkali-activated solution and first mix and stir at a rotation speed of 40-60 r / min for 60-90 s, and then mix and stir at a rotation speed of 120-140 r / min for 60-80 s to obtain a uniform mixed slurry.

[0049] In some embodiments, the water reducing agent can be added and mixed and stirred simultaneously with desulfurized ash, fly ash, mineral powder, and cement, then the remaining water is added for pre-wetting, and finally an alkali activator solution is added and mixed and stirred to obtain a uniform mixed slurry.

[0050] In some embodiments, in step S4, the curing conditions include: the temperature is 18°C to 22°C (for example, it can be 18°C, 19°C, 20°C, 21°C, 22°C), the humidity is 94% to 96% (for example, it can be 94%, 95%, 96%), and the time is 1 to 28 days (for example, it can be 1 day, 3 days, 7 days, 21 days, 28 days).

[0051] In some embodiments, step S4 specifically includes:

[0052] Pour the mixed slurry into a mold, after vibrating for 2 to 5 minutes and covering it with a plastic wrap, place it in a normal temperature incubator for curing to obtain the high-strength desulfurized ash-based cementitious material.

[0053] In this embodiment, vibration can make the slurry denser, so as to better carry out the hydration reaction and make it have better performance; covering the mold with plastic wrap can slow down the water loss in the slurry and avoid affecting the normal hydration reaction of the slurry due to opening and closing the curing box multiple times.

[0054] The embodiment of the present invention provides an application of the high-strength desulfurized ash-based cementitious material described in any one of the foregoing embodiments in the preparation of concrete or masonry mortar.

[0055] The present invention will be further described below through specific embodiments.

[0056] Examples 1 to 8

[0057] Prepare the high-strength desulfurized ash-based cementitious material according to the following steps:

[0058] (1) Weigh each raw material according to the mass fraction ratio shown in Table 1 for standby;

[0059] (2) Dissolve the alkali activator in 50% mass of water and age for 24 hours to obtain an alkali activator solution;

[0060] (3) Put the desulfurized ash, fly ash, mineral powder, and cement into a mixer and mix and stir at a slow speed of 60 r / min for 120 s, then add the remaining 50% mass of water to pre-wet the mixed and stirred raw materials for 60 s, then add the water reducing agent and mix and stir for 30 s, and finally add the alkali activator solution and first mix and stir at a slow speed of 60 r / min for 60 s, and then mix and stir at a fast speed of 140 r / min for 60 s to obtain a uniform mixed slurry;

[0061] (4) Pour the mixed slurry into a mold of 40mm×40mm×40mm in two times. Each time, it is necessary to insert and tamp several times with a knife to avoid stratification of the slurry loaded before and after; then vibrate on a vibrating table for 120s, scrape the surface of the slurry flat, cover it with plastic wrap, and then place it in a normal temperature curing box for curing for 3 days and 28 days to obtain a high-strength desulfurized ash-based cementitious material.

[0062] Comparative Example 1 to Comparative Example 4

[0063] Prepare the cementitious material according to the following steps:

[0064] (1) Weigh each raw material according to the mass fraction ratio shown in Table 1 and set aside;

[0065] (2) Put the desulfurized ash, fly ash, slag powder and cement into a mixer and mix and stir at a low speed of 60r / min for 120s. Then add 50% of the water by mass to pre-wet the mixed and stirred raw materials for 60s. Then add the remaining 50% of the water by mass and first mix and stir at a low speed of 60r / min for 60s, and then mix and stir at a high speed of 140r / min for 60s to obtain a uniform mixed slurry;

[0066] (4) Pour the mixed slurry into a mold of 40mm×40mm×40mm in two times. Each time, it is necessary to insert and tamp several times with a knife to avoid stratification of the slurry loaded before and after; then vibrate on a vibrating table for 120s, scrape the surface of the slurry flat, cover it with plastic wrap, and then place it in a normal temperature curing box for curing for 3 days and 28 days to obtain the cementitious material.

[0067] Comparative Example 5 to Comparative Example 8

[0068] Prepare the cementitious material according to the following steps:

[0069] (1) Weigh each raw material according to the mass fraction ratio shown in Table 1 and set aside;

[0070] (2) Put the desulfurized ash, fly ash, slag powder and cement into a mixer and mix and stir at a low speed of 60r / min for 120s. Then add 50% of the water by mass to pre-wet the mixed and stirred raw materials for 60s. Then add the water reducing agent and mix and stir for 30s. Finally, add the remaining 50% of the water by mass and first mix and stir at a low speed of 60r / min for 60s, and then mix and stir at a high speed of 140r / min for 60s to obtain a uniform mixed slurry, to obtain a uniform mixed slurry;

[0071] (4) Pour the mixed slurry into a mold of 40mm×40mm×40mm in two times. Each time, it is necessary to insert and tamp several times with a knife to avoid stratification of the slurry loaded before and after; then vibrate on a vibrating table for 120s, scrape the surface of the slurry flat, cover it with plastic wrap, and then place it in a normal temperature curing box for curing for 3 days and 28 days to obtain the cementitious material.

[0072] Table 1 shows the mass fraction ratios of the raw materials used in Examples 1 to 8 and Comparative Examples 1 to 8.

[0073] Table 1

[0074]

[0075]

[0076]

[0077] In Table 1, " / " indicates that the raw material was not used.

[0078] Performance tests on the compressive strength, setting time, and soundness of the cementitious materials prepared in the above Examples 1 to 8 and Comparative Examples 1 to 8 were carried out.

[0079] The test method for compressive strength is as follows: According to the standard GB / T 17671-2021 "Test Method for Strength of Cement Mortar (ISO Method)", the prepared cementitious material was used as a sample for compressive strength testing. One side of a 40mm×40mm×40mm sample was placed on a testing machine (MODEL electro-hydraulic servo compression testing machine), and the load was applied at a loading speed of 2.4kN / s until the sample was damaged. The average value was obtained from three samples in each group.

[0080] The test methods for setting time and soundness are as follows: According to the standard GB / T 1346-2011 "Test Methods for Water Requirement of Normal Consistency, Setting Time and Soundness of Cement", a Vicat apparatus was used to test the initial setting time and final setting time of the paste. The soundness was tested by the Le Chatelier method. The paste prepared under standard consistency was poured into the Le Chatelier mold, cured for 24h, and then boiled. The distance difference between the pointers of the Le Chatelier mold before and after boiling was compared. If the distance difference between the pointers before and after boiling was less than 5mm, the soundness was qualified.

[0081] Table 2 shows the performance data of the compressive strength, setting time, and soundness of the cementitious materials prepared in Examples 1 to 8 and Comparative Examples 1 to 8. Among them, the 3d compressive strength represents the compressive strength of the cementitious material obtained after 3 days of curing, and the 28d compressive strength represents the compressive strength of the cementitious material obtained after 28 days of curing.

[0082] Table 2

[0083]

[0084] It can be seen from the data in Table 2 that the high-strength desulfurized ash-based cementitious material of the present invention has high mechanical properties and good volume stability, showing excellent comprehensive performance. In particular, compared with the comparative examples, the cementitious material of the present invention has higher compressive strength and shorter final setting time, has better comprehensive performance, and can better meet the use requirements of the cementitious material.

[0085] In summary, the high-strength desulfurized ash-based cementitious material provided by the present invention is prepared from the following raw materials in parts by mass: 30 to 70 parts of desulfurized ash, 20 to 70 parts of fly ash, 0 to 30 parts of mineral powder, 0 to 10 parts of cement, 2 to 8 parts of alkali activator, 1 to 4 parts of water reducer, and 20 to 35 parts of water. It has high mechanical properties and good volume stability, shows excellent comprehensive performance, and can well meet the use requirements of the cementitious material.

[0086] It should be understood that the application of the present invention is not limited to the above examples. For those of ordinary skill in the art, improvements or changes can be made according to the above description. All such improvements and changes should fall within the protection scope of the appended claims of the present invention.

Claims

1. A high-strength desulfurized ash-based cementitious material, characterized in that: The invention is prepared by including the following raw materials in parts by weight: 30 to 70 parts of desulfurized ash, 20 to 70 parts of fly ash, 0 to 30 parts of mineral powder, 0 to 10 parts of cement, 2 to 8 parts of alkali activator, 1 to 4 parts of water reducing agent and 20 to 35 parts of water.

2. The high-strength desulfurized ash-based cementitious material according to claim 1, characterized in that: The invention is prepared by the following raw materials in parts by weight: 30 to 70 parts of desulfurized ash, 20 to 70 parts of fly ash, 5 to 30 parts of mineral powder, 5 to 10 parts of cement, 2 to 8 parts of alkali activator, 1 to 4 parts of water reducing agent and 20 to 35 parts of water.

3. The high-strength desulfurized ash-based cementitious material according to claim 1, characterized in that: The alkaline activator is at least one of sodium silicate, sodium hydroxide, sodium carbonate, potassium hydroxide and sodium sulfate.

4. The high-strength desulfurized ash-based cementitious material according to claim 1, characterized in that: The alkaline activator is sodium silicate with a modulus of 1 to 2.

5. The high-strength desulfurized ash-based cementitious material according to claim 1, characterized in that: The water reducer is at least one of a polycarboxylic acid water reducer, a naphthalene water reducer, a melamine water reducer and sodium lignin sulfonate.

6. A method for preparing a high-strength desulfurized ash-based cementitious material according to any one of claims 1 to 5, characterized in that: include: Step S1, weighing each raw material according to the mass fraction ratio for standby use; Step S2, dissolving the alkaline activator in a portion of water and aging the water to obtain an alkaline activating solution; Step S3, mixing desulfurized ash, fly ash, mineral powder, cement, water reducing agent and remaining water, and then adding alkali activating liquid and mixing to obtain a mixed slurry; Step S4, pouring the mixed slurry into a mold, and obtaining the high-strength desulfurization ash-based cementitious material through curing.

7. The method for preparing a high-strength desulfurized ash-based cementitious material according to claim 6, characterized in that: In the step S2, the mass of the part of water is 40% to 60% of the total mass of water, and the aging time is 24 to 36 hours.

8. The method for preparing a high-strength desulfurized ash-based cementitious material according to claim 6, characterized in that: The step S3 specifically includes: The desulfurized ash, fly ash, mineral powder and cement are mixed and stirred at a speed of 40 to 60 r / min for 120 to 150 seconds, and the remaining water is added to pre-wet the raw materials for 60 to 80 seconds, and then the water reducing agent is added and mixed and stirred for 20 to 40 seconds. Finally, the alkali activating solution is added and mixed and stirred at a speed of 40 to 60 r / min for 60 to 90 seconds, and then mixed and stirred at a speed of 120 to 140 r / min for 60 to 80 seconds to obtain a uniform mixed slurry.

9. The method for preparing a high-strength desulfurized ash-based cementitious material according to claim 6, characterized in that: In step S4, the curing conditions include: temperature of 18° C. to 22° C., humidity of 94% to 96%, and time of 1 to 28 days.

10. Use of the high-strength desulfurized ash-based cementitious material according to any one of claims 1 to 5 in the preparation of concrete or masonry mortar.

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