Preparation method of anti-carbonization full-solid waste slag-sulfoaluminate cementitious material

Abstract

The application relates to the technical field of cement-based material preparation, and particularly discloses a preparation method of a carbonation-resistant full-solid-waste mine slag-sulfoaluminate cementitious material, which comprises the following steps: (1) wet material formed by lead-zinc tailing ore powder and water is placed in a reaction container, and then the reaction container is sealed and heated; after the heating treatment is completed, the obtained product is mixed with iron powder and / or iron oxide compound powder and water, and then stirring treatment is carried out; after the stirring treatment is completed, the solid product is separated out, heated and dried in an air atmosphere, and then carbonation-resistant tailing ore powder is obtained; (2) the carbonation-resistant tailing ore powder is mixed with sulfoaluminate cement powder, and then mechanical grinding treatment is carried out, so that modified sulfoaluminate cement is obtained; and (3) blast furnace slag powder, the modified sulfoaluminate cement, fly ash, waste gypsum powder, alkali activator, gypsum and water reducing agent are used as raw materials, and then the raw materials are uniformly mixed, so that the cementitious material is obtained. The application not only realizes the resource utilization of industrial solid waste, but also effectively improves the carbonation resistance of the cementitious material and the service durability of the cementitious material.

Description

Technical Field

[0001] This invention relates to the field of cement-based material preparation technology, specifically to a method for preparing an anti-carbonation all-solid waste slag-sulfoaluminate cementitious material. Background Technology

[0002] The information disclosed in this background section is intended only to enhance understanding of the overall background of the invention and is not necessarily to be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.

[0003] Traditional cement-based materials primarily use silicate cement clinker as the cementing component. Their preparation requires high-temperature calcination of raw materials, which is not only energy-intensive but also emits large amounts of carbon dioxide. Solid waste-based cementitious materials, on the other hand, are hydraulic cementitious materials formed from siliceous aluminate industrial solid waste as raw materials and supplemented with activators such as gypsum. They can replace traditional silicate cement clinker in concrete preparation, with carbon emissions only 5-10% of those of silicate cement. This not only opens up a new path for the green development of the cement industry and promotes its low-carbon transformation but also facilitates the resource utilization of solid waste.

[0004] However, due to the generally low gelling activity and slow hydration reaction initiation of siliceous aluminate industrial solid waste, early strength development is insufficient, limiting the application of solid waste-based cementitious materials in some special cases. Sulfoaluminate cement, a clinker mainly composed of anhydrous calcium sulfoaluminate and dicalcium silicate, is characterized by early strength and high strength. Combining it with solid waste-based cementitious materials can help overcome the problem of insufficient early strength development. However, the inventors have found that because the hydration product of sulfoaluminate cement is mainly ettringite, its resistance to carbonation is poor. During service, it is prone to strength reduction under the erosion of carbon dioxide, resulting in a decrease in the load-bearing capacity of building structures. Therefore, this composite material still suffers from insufficient durability. Summary of the Invention

[0005] To address the aforementioned problems, this invention provides a method for preparing a carbonization-resistant solid waste slag-sulfoaluminate cementitious material. This method not only achieves the resource utilization of industrial solid waste but also effectively improves the carbonization resistance of the cementitious material, thereby enhancing its service durability. Specifically, the technical solution of this invention is as follows.

[0006] A method for preparing a carbonization-resistant solid waste slag-sulfoaluminate cementitious material includes the following steps:

[0007] (1) The wet material formed by lead-zinc tailings powder and water is placed in a reaction vessel and then heated in a sealed container. After the reaction is completed, the product is mixed with iron powder and / or iron oxide powder and water and stirred. After the reaction is completed, the solid product is separated and heated and dried in an air atmosphere to obtain anti-carbonization tailings powder.

[0008] (2) The anti-carbonization tailings powder is mixed with sulfoaluminate cement powder and then mechanically ground to obtain modified sulfoaluminate cement.

[0009] (3) The cementitious material is obtained by mixing blast furnace slag powder, the modified sulfoaluminate cement, fly ash, waste gypsum powder, alkali activator, gypsum and water reducing agent as raw materials.

[0010] Further, in step (1), the moisture content of the wet material is 24-32%. Optionally, the fineness of the lead-zinc tailings powder is not less than 200 mesh.

[0011] Furthermore, in step (1), the temperature of the heat treatment is 50~70℃ and the time is 9~14 hours.

[0012] Further, in step (1), the molar ratio of Fe element provided by the iron powder and / or ferrooxide powder to S element in the lead-zinc tailings powder is 1.1~1.2:2, so as to convert the sulfuric acid formed by FeS2 in the lead-zinc tailings powder into ferric sulfate or ferrous sulfate. Optionally, the ferrooxide includes at least one of: iron oxide, ferrous oxide, and magnetite.

[0013] Further, in step (1), the ratio of the product to water is 1g:3~5mL. Optionally, the stirring time is not less than 20min.

[0014] Furthermore, in step (1), the drying temperature is 70~80℃ and the time is 1~1.5 hours.

[0015] Further, in step (2), the ratio of the anti-carbonation tailings powder to the sulfoaluminate cement powder is 1.0 parts by weight: 0.45~0.52 parts by weight. Optionally, the fineness of the modified sulfoaluminate cement is not less than 300 mesh.

[0016] Further, in step (3), the proportions of each component in the raw materials are as follows: 60-75 parts by weight of blast furnace slag powder, 42-55 parts by weight of modified sulfoaluminate cement, 18-25 parts by weight of fly ash, 16-22 parts by weight of waste gypsum powder, 7-11 parts by weight of alkali activator, and 2-3.1 parts by weight of water-reducing agent.

[0017] Furthermore, in step (3), the waste gypsum includes at least one of the following: desulfurized gypsum, fluorogypsum, phosphogypsum, etc.

[0018] Furthermore, in step (3), the alkaline activator includes at least one of sodium hydroxide, potassium hydroxide, sodium silicate, etc.

[0019] Further, in step (3), the water-reducing agent includes at least one of the following: polycarboxylate water-reducing agent, naphthalene water-reducing agent, aliphatic water-reducing agent, lignin sulfonate water-reducing agent, etc.

[0020] Furthermore, in step (3), the raw materials also include an anti-carbonation reinforcing agent prepared by the following method: silicate cement-based concrete recycled micro powder is mixed with a magnesium ion solution, then an alkaline solution is added and mixed thoroughly before standing. After completion, the solid product is separated and calcined to obtain the anti-carbonation reinforcing agent.

[0021] Further, the ratio of the recycled silicate cement-based concrete powder to the magnesium ion solution is 1g:2~3.5mL. Optionally, the mass fraction of the magnesium ion solution is not less than 15%. The recycled powder is obtained by crushing and grinding waste building concrete based on silicate cement.

[0022] Furthermore, the magnesium ion solution includes at least one of magnesium chloride solution, magnesium sulfate solution, and magnesium nitrate solution.

[0023] Further, the magnesium ions in the magnesium ion solution are added to the alkaline solution in a manner that ensures complete precipitation of the magnesium ions. Optionally, the alkaline solution includes at least one of sodium hydroxide solution, potassium hydroxide solution, ammonia water, etc.

[0024] Furthermore, the calcination treatment is carried out at a temperature of 560~630℃ for 2~2.5 hours.

[0025] Further, the proportion of the anti-carbonation reinforcing agent is 14-20% of the total content of the blast furnace slag powder, modified sulfoaluminate cement, and fly ash. Optionally, the fineness of the anti-carbonation reinforcing agent is not less than 300 mesh.

[0026] Furthermore, in step (3), the raw materials may be mixed with components such as fibers as needed to further improve the mechanical properties of the obtained cementitious material. Optionally, the fibers include at least one of basalt fibers, organic fibers, and steel fibers.

[0027] Compared with the prior art, the technical solution of the present invention has at least the following beneficial effects:

[0028] While adding sulfoaluminate cement to solid waste-based cementitious materials can improve early strength, the poor carbonization resistance of the hydration products of sulfoaluminate cement can easily lead to strength reduction during service. Therefore, this invention modifies sulfoaluminate cement with anti-carbonation tailings powder prepared from lead-zinc tailings powder. This not only improves its carbonization resistance and alleviates the strength reduction problem, but also transforms lead-zinc tailings, an industrial solid waste, into an active cementitious component for preparing the all-solid waste slag-sulfoaluminate cementitious material of this invention, achieving multiple utilizations of lead-zinc tailings. To this end, this invention first heat-treats the wet material formed by lead-zinc tailings powder and water, converting FeS2 in it into ferrous sulfate and sulfuric acid under the action of moisture and oxygen. Simultaneously, the sulfuric acid in this process can also acid-activate the lead-zinc tailings powder, depolymerizing the inert mineral phases and improving the cementitious activity of the lead-zinc tailings powder. Then, after adding iron powder and / or ferric oxide powder, the sulfuric acid is converted back into ferrous sulfate / ferric sulfate. After drying in air, the ferrous sulfate is oxidized to ferric sulfate. The anti-carbonation tailings powder obtained after the above treatment is mechanically ground with sulfoaluminate cement powder, and the Fe provided by the anti-carbonation tailings powder is utilized during the hydration process. 3+ Al in ettringite crystals, a hydration product of sulfoaluminate cement, is partially replaced. 3+ This increases the crystal bond energy, thereby increasing the amount of Ca in the crystal. 2+ The leaching difficulty is reduced, thus improving its resistance to carbonization. Simultaneously, the sulfate ions provided by the anti-carbonization tailings powder can be used for the formation of ettringite crystals. Furthermore, the activated lead-zinc tailings powder not only serves as a cementing material but also forms more cementing products, thereby contributing to the improvement of early strength.

[0029] Furthermore, the present invention utilizes a carbonation-resistant reinforcing agent prepared from recycled silicate cement-based concrete powder, which not only achieves the resource utilization of waste concrete but also further enhances the carbonation resistance of the sulfoaluminate cement. This is because: after calcination, the magnesium oxide and hydration product calcium hydroxide in the recycled powder dehydrate to form magnesium oxide and calcium oxide, while another type of hydration product—hydrated calcium silicate and hydrated calcium aluminate—also dehydrates. When added to the all-solid waste slag-sulfoaluminate cementitious material of the present invention, not only can the magnesium hydroxide formed after the magnesium oxide hydration, with its micro-expansion characteristics, fill and compact the pores in the cementitious material, reducing the channels for carbon dioxide penetration, but the formed magnesium hydroxide can also solidify the invading carbon dioxide (Mg(OH)2 + CO2 = MgCO3 + H2O) in the later stages of the cementitious material's service life, reducing the erosion of ettringite. The heat released by the calcium oxide upon contact with water during the magnesium oxide hydration process also helps to accelerate the hydration reaction and promote the conversion of magnesium oxide. Simultaneously, the dehydrated hydrated calcium silicate and calcium aluminate act as nucleation sites, promoting the formation of hydration products in the cementitious material, thereby enhancing the early strength development of the cementitious material. This invention utilizes the characteristics of the recycled silicate cement-based concrete powder, modifying it to not only achieve higher-value resource utilization but also enhance the carbonation resistance of ettringite, helping to further prevent strength reduction. Attached Figure Description

[0030] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention and do not constitute an undue limitation of the invention.

[0031] Figure 1 The image shows a physical sample of the anti-carbonization tailings powder prepared in Example 1 below.

[0032] Figure 2 The following is a diagram showing the compressive strength test results for Example 1.

[0033] Figure 3 The image shows a physical sample of the anti-carbonization tailings powder prepared in Example 2 below.

[0034] Figure 4 The image shows a physical sample of the anti-carbonation reinforcing agent prepared in Example 2 below.

[0035] Figure 5 The following is a diagram showing the compressive strength test results for Example 2.

[0036] Figure 6 The image shows a physical sample of the anti-carbonization tailings powder prepared in Example 3 below.

[0037] Figure 7 The image shows the effect of a physical sample of the anti-carbonation reinforcing agent prepared in Example 3 below.

[0038] Figure 8 The following is a diagram showing the compressive strength test results for Example 3. Detailed Implementation

[0039] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Unless otherwise defined, all technical and scientific terms used in this invention have the same meaning as those skilled in the art. The preferred embodiments and materials described in this invention are for illustrative purposes only. The technical solutions of the present invention will now be further described with reference to specific embodiments.

[0040] Example 1: A method for preparing a carbonization-resistant solid waste slag-sulfoaluminate cementitious material, comprising the following steps:

[0041] (1) Water was added to lead-zinc tailings powder with a fineness of 300 mesh (the main component is siliceous aluminous mineral phase, and the FeS2 content is 12.37 wt.%) and stirred evenly to form a wet material with a moisture content of 28%. The wet material was then placed in a reaction vessel and sealed, and then heated to 55°C and kept at that temperature for 10 hours. After completion, iron powder was added to the obtained product, and the molar ratio of Fe element provided by the iron powder to S element in the lead-zinc tailings powder was 1.1:2. Then, water was added according to the ratio of product to water of 1 g: 4 mL and stirred continuously for 20 min. After completion, the solid product was filtered out and kept at 70°C in air for 1.5 hours with continuous stirring. After completion, anti-carbonization tailings powder (such as...) was obtained. Figure 1 (As shown).

[0042] (2) The anti-carbonation tailings powder and sulfoaluminate cement powder are mixed in a ratio of 1.0 parts by weight to 0.5 parts by weight and then mechanically ground and passed through a 400-mesh sieve to obtain modified sulfoaluminate cement.

[0043] (3) Weigh the following raw materials according to the following proportions: 70 parts by weight of granulated blast furnace slag powder, 50 parts by weight of modified sulfoaluminate cement in this embodiment, 20 parts by weight of Grade I fly ash, 18 parts by weight of desulfurized gypsum powder, 8.5 parts by weight of sodium hydroxide, and 2.5 parts by weight of polycarboxylate superplasticizer. Pour the above raw materials into a mixer and mechanically stir for 5 minutes to obtain the cementitious material.

[0044] Performance testing: The anti-cementing material prepared in this embodiment was mixed with water at a water-cement ratio of 0.42 and stirred evenly. The resulting slurry was then poured into a mold, demolded after hardening for 24 hours, and then cured in a curing chamber for 28 days. The three specimens obtained were then subjected to compressive strength testing (e.g., ...). Figure 2(As shown) and the average value 'a' was calculated. Simultaneously, three other specimens were placed in a carbonization chamber for 7 days of carbonization treatment, and their compressive strength was tested and the average value 'b' was calculated. The ratio of 'b' to 'a' was then used as the compressive strength loss rate; the larger the value, the smaller the strength loss caused by carbonization, and the stronger the carbonization resistance of the cementitious material. The measured compressive strength loss rate was 92.14%.

[0045] Example 2: A method for preparing a carbonization-resistant solid waste slag-sulfoaluminate cementitious material, comprising the following steps:

[0046] (1) Water was added to lead-zinc tailings powder with a fineness of 200 mesh (same as in Example 1) and stirred evenly to form a wet material with a moisture content of 24%. The wet material was then placed in a reaction vessel and sealed, and heated to 70°C and kept at that temperature for 9 hours. After completion, iron powder was added to the obtained product, with the molar ratio of Fe to S in the lead-zinc tailings powder being 1.1:2. Then, water was added according to the ratio of product to water of 1g:3mL, and the mixture was stirred continuously for 25 minutes. After completion, the solid product was filtered out and dried in air at 80°C for 1 hour with continuous stirring. After completion, anti-carbonization tailings powder (such as...) was obtained. Figure 3 (As shown).

[0047] (2) The anti-carbonation tailings powder and sulfoaluminate cement powder are mixed in a ratio of 1.0 parts by weight to 0.45 parts by weight, then mechanically ground and passed through a 300-mesh sieve to obtain modified sulfoaluminate cement.

[0048] (3) Mix 200-mesh silicate cement-based concrete recycled micro powder with 15% magnesium sulfate solution at a ratio of 1g:3.5mL and stir until homogeneous. Then, according to Mg 2+ OH - A sodium hydroxide solution was added at a molar ratio of 1:1.15, stirred, and allowed to stand for 10 minutes. The solid product was then filtered out and heated to 560℃ for 2.5 hours. After cooling to room temperature, it was ground and passed through a 300-mesh sieve to obtain the anti-carbonation reinforcing agent (such as...). Figure 4 (As shown).

[0049] (4) Weigh the following raw materials according to the following proportions: 60 parts by weight of granulated blast furnace slag powder, 42 parts by weight of modified sulfoaluminate cement of this embodiment, 18 parts by weight of Grade I fly ash, 16 parts by weight of desulfurized gypsum powder, 7 parts by weight of sodium silicate, 2 parts by weight of polycarboxylate superplasticizer, and 16.8 parts by weight of the anti-carbonation reinforcing agent of this embodiment. Pour the above raw materials into a mixer and mechanically stir for 5 minutes to obtain the cementitious material.

[0050] Performance testing: The compressive strength (e.g., before and after carbonization treatment) of the cementitious material prepared in this embodiment was tested using the same method as in Example 1 above. Figure 5 (As shown), then the compressive strength loss rate was calculated to be 97.59%.

[0051] Example 3: A method for preparing a carbonization-resistant solid waste slag-sulfoaluminate cementitious material, comprising the following steps:

[0052] (1) Water was added to lead-zinc tailings powder with a fineness of 250 mesh (same as in Example 1) and stirred evenly to form a wet material with a moisture content of 32%. The wet material was then placed in a reaction vessel and sealed, and then heated to 50°C and kept at that temperature for 14 hours. After completion, iron oxide powder was added to the obtained product, with the molar ratio of Fe element provided by the iron oxide powder to S element in the lead-zinc tailings powder being 1.2:2. Then, water was added according to the ratio of product to water of 1g:5mL, and the mixture was stirred continuously for 25 minutes. After completion, the solid product was filtered out and dried in air at 75°C for 1 hour with continuous stirring. After completion, anti-carbonization tailings powder (such as...) was obtained. Figure 6 (As shown).

[0053] (2) The anti-carbonation tailings powder and sulfoaluminate cement powder are mixed in a ratio of 1.0 parts by weight to 0.52 parts by weight, then mechanically ground and passed through a 350-mesh sieve to obtain modified sulfoaluminate cement.

[0054] (3) Mix 200-mesh silicate cement-based concrete recycled micro powder with 25% magnesium nitrate solution at a ratio of 1g:2mL and stir until homogeneous. Then, according to Mg 2+ OH - Ammonia water was added at a molar ratio of 1:1.1, stirred, and allowed to stand for 10 minutes. The solid product was then filtered out and heated to 630℃ for 2 hours. After cooling to room temperature, it was ground and passed through a 350-mesh sieve to obtain the anti-carbonation reinforcing agent (such as...). Figure 7 (As shown).

[0055] (4) Weigh the following raw materials according to the following proportions: 75 parts by weight of granulated blast furnace slag powder, 55 parts by weight of modified sulfoaluminate cement of this embodiment, 25 parts by weight of Grade I fly ash, 22 parts by weight of desulfurized gypsum powder, 6 parts by weight of sodium hydroxide, 5 parts by weight of sodium silicate, 3.1 parts by weight of sodium lignosulfonate water-reducing agent, and 31 parts by weight of the anti-carbonation reinforcing agent of this embodiment. Pour the above raw materials into a mixer and mechanically stir for 5 minutes to obtain the cementitious material.

[0056] Performance testing: The compressive strength (e.g., before and after carbonization treatment) of the cementitious material prepared in this embodiment was tested using the same method as in Example 1 above. Figure 8 (As shown), then the compressive strength loss rate was calculated to be 98.06%.

[0057] Example 4: A method for preparing a solid waste slag-sulfoaluminate cementitious material, comprising the following steps:

[0058] Weigh the following raw materials according to the proportions: 70 parts by weight of granulated blast furnace slag powder, 50 parts by weight of sulfoaluminate cement, 20 parts by weight of Grade I fly ash, 18 parts by weight of desulfurized gypsum powder, 8.5 parts by weight of sodium hydroxide, and 2.5 parts by weight of polycarboxylate superplasticizer. Pour the above raw materials into a mixer and mechanically stir for 5 minutes to obtain the cementitious material.

[0059] Performance testing: The compressive strength of the cementitious material prepared in this embodiment before and after carbonization treatment was tested using the same method as in Example 1 above, and then the compressive strength loss rate was calculated to be 74.33%.

[0060] Example 5: A method for preparing a carbonization-resistant solid waste slag-sulfoaluminate cementitious material, comprising the following steps:

[0061] (1) Water was added to lead-zinc tailings powder with a fineness of 300 mesh (same as in Example 1) and stirred evenly to form a wet material with a moisture content of 28%. The wet material was then placed in a reaction vessel and sealed, and then heated to 55°C and kept at that temperature for 10 hours. After completion, the obtained solid product was kept at 70°C in air for 1.5 hours with continuous stirring. After completion, anti-carbonization tailings powder was obtained.

[0062] (2) The anti-carbonation tailings powder and sulfoaluminate cement powder are mixed in a ratio of 1.0 parts by weight to 0.5 parts by weight and then mechanically ground and passed through a 400-mesh sieve to obtain modified sulfoaluminate cement.

[0063] (3) Weigh the following raw materials according to the following proportions: 70 parts by weight of granulated blast furnace slag powder, 50 parts by weight of modified sulfoaluminate cement in this embodiment, 20 parts by weight of Grade I fly ash, 18 parts by weight of desulfurized gypsum powder, 8.5 parts by weight of sodium hydroxide, and 2.5 parts by weight of polycarboxylate superplasticizer. Pour the above raw materials into a mixer and mechanically stir for 5 minutes to obtain the cementitious material.

[0064] Performance testing: The compressive strength of the cementitious material prepared in this embodiment before and after carbonization treatment was tested using the same method as in Example 1 above, and then the compressive strength loss rate was calculated to be 86.72%.

[0065] Example 6: A method for preparing a carbonization-resistant solid waste slag-sulfoaluminate cementitious material, comprising the following steps:

[0066] (1) The lead-zinc tailings powder with a fineness of 300 mesh (same as in Example 1) and sulfoaluminate cement powder were mixed in a ratio of 1.0 parts by weight: 0.5 parts by weight and then mechanically ground. The mixture was then passed through a 400-mesh sieve to obtain modified sulfoaluminate cement.

[0067] (2) Weigh the following raw materials according to the following proportions: 70 parts by weight of granulated blast furnace slag powder, 50 parts by weight of modified sulfoaluminate cement in this embodiment, 20 parts by weight of Grade I fly ash, 18 parts by weight of desulfurized gypsum powder, 8.5 parts by weight of sodium hydroxide, and 2.5 parts by weight of polycarboxylate superplasticizer. Pour the above raw materials into a mixer and mechanically stir for 5 minutes to obtain the cementitious material.

[0068] Performance testing: The compressive strength of the cementitious material prepared in this embodiment before and after carbonization treatment was tested using the same method as in Example 1 above, and then the compressive strength loss rate was calculated to be 79.42%.

[0069] Example 7: A method for preparing a carbonization-resistant solid waste slag-sulfoaluminate cementitious material, comprising the following steps:

[0070] (1) 200-mesh silicate cement-based concrete recycled micro powder and 15% magnesium sulfate solution were mixed at a ratio of 1g:3.5mL and stirred evenly. Then, according to Mg... 2+ OH - A sodium hydroxide solution was added at a molar ratio of 1:1.15, stirred, and allowed to stand for 10 minutes. The solid product was then filtered out, dried, ground, and passed through a 300-mesh sieve to obtain the anti-carbonation reinforcing agent.

[0071] (2) Weigh the following raw materials according to the following proportions: 60 parts by weight of granulated blast furnace slag powder, 42 parts by weight of the modified sulfoaluminate cement of Example 2 above, 18 parts by weight of Grade I fly ash, 16 parts by weight of desulfurized gypsum powder, 7 parts by weight of sodium silicate, 2 parts by weight of polycarboxylate superplasticizer, and 16.8 parts by weight of the anti-carbonation reinforcing agent described in this example. Pour the above raw materials into a mixer and mechanically stir for 5 minutes to obtain the cementitious material.

[0072] Performance testing: The compressive strength of the cementitious material prepared in this embodiment before and after carbonization treatment was tested using the same method as in Example 1 above, and then the compressive strength loss rate was calculated to be 93.68%.

[0073] Example 8: A method for preparing a carbonization-resistant solid waste slag-sulfoaluminate cementitious material, comprising the following steps:

[0074] (1) The silicate cement-based concrete recycled micro powder was ground and passed through a 350-mesh sieve to obtain an anti-carbonation reinforcing agent.

[0075] (2) Weigh the following raw materials according to the following proportions: 75 parts by weight of granulated blast furnace slag powder, 55 parts by weight of modified sulfoaluminate cement of Example 3 above, 25 parts by weight of Grade I fly ash, 22 parts by weight of desulfurized gypsum powder, 6 parts by weight of sodium hydroxide, 5 parts by weight of sodium silicate, 3.1 parts by weight of sodium lignosulfonate water-reducing agent, and 31 parts by weight of the anti-carbonation reinforcing agent of this example. Pour the above raw materials into a mixer and mechanically stir for 5 minutes to obtain the cementitious material.

[0076] Performance testing: The compressive strength of the cementitious material prepared in this embodiment before and after carbonization treatment was tested using the same method as in Example 1 above, and then the compressive strength loss rate was calculated to be 92.76%.

[0077] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., should be included within the protection scope of the present invention.

Claims

1. A method for preparing a carbonization-resistant solid waste slag-sulfoaluminate cementitious material, characterized in that, Includes the following steps: (1) The wet material formed by lead-zinc tailings powder and water is placed in a reaction vessel and then sealed for heating treatment. FeS2 in the vessel is converted into ferrous sulfate and sulfuric acid under the action of water and oxygen. After completion, the product is mixed with iron powder and / or iron oxide powder and water and stirred. After completion, the solid product is separated and heated and dried in air atmosphere to obtain anti-carbonization tailings powder. (2) The anti-carbonation tailings powder and sulfoaluminate cement powder are mixed in a ratio of 1.0 parts by weight to 0.45~0.52 parts by weight and then mechanically ground to obtain modified sulfoaluminate cement; (3) The cementitious material is obtained by mixing 60-75 parts by weight of blast furnace slag powder, 42-55 parts by weight of modified sulfoaluminate cement, 18-25 parts by weight of fly ash, 16-22 parts by weight of waste gypsum powder, 7-11 parts by weight of alkali activator and 2-3.1 parts by weight of water reducing agent.

2. The preparation method of the anti-carbonization solid waste slag-sulfoaluminate cementitious material according to claim 1, characterized in that, In step (1), the moisture content of the wet material is 24-32%; Alternatively, in step (1), the fineness of the lead-zinc tailings powder is not less than 200 mesh; Alternatively, in step (1), the temperature of the heat treatment is 50~70℃ and the time is 9~14 hours.

3. The preparation method of the anti-carbonization solid waste slag-sulfoaluminate cementitious material according to claim 1, characterized in that, In step (1), the molar ratio of Fe element provided by the iron powder and / or iron oxide powder to S element in the lead-zinc tailings powder is 1.1~1.2:2; Alternatively, in step (1), the iron oxide includes at least one of: iron oxide, ferrous oxide, and iron(II,III) oxide; Alternatively, in step (1), the ratio of the product to water is 1g:3~5mL; Alternatively, in step (1), the stirring time shall not be less than 20 minutes; Alternatively, in step (1), the drying temperature is 70~80℃ and the time is 1~1.5 hours.

4. The preparation method of the anti-carbonization solid waste slag-sulfoaluminate cementitious material according to claim 1, characterized in that, In step (2), the fineness of the modified sulfoaluminate cement is not less than 300 mesh.

5. The preparation method of the anti-carbonization solid waste slag-sulfoaluminate cementitious material according to claim 1, characterized in that, In step (3), the waste gypsum includes at least one of desulfurized gypsum, fluorogypsum, and phosphogypsum; Alternatively, in step (3), the alkaline activator includes at least one of sodium hydroxide, potassium hydroxide, and sodium silicate; Alternatively, in step (3), the water-reducing agent includes at least one of the following: polycarboxylate water-reducing agent, naphthalene water-reducing agent, aliphatic water-reducing agent, and lignin sulfonate water-reducing agent.

6. The method for preparing the anti-carbonization solid waste slag-sulfoaluminate cementitious material according to any one of claims 1-5, characterized in that, In step (3), the raw materials also include an anti-carbonation reinforcing agent prepared by the following method: the silicate cement-based concrete recycled micro powder is mixed with magnesium ion solution, then alkali solution is added and mixed, and then left to stand; after completion, the solid product is separated and calcined to obtain the anti-carbonation reinforcing agent.

7. The preparation method of the anti-carbonization all-solid waste slag-sulfoaluminate cementitious material according to claim 6, characterized in that, The ratio of the recycled silicate cement-based concrete powder to the magnesium ion solution is 1g:2~3.5mL; or, the mass fraction of the magnesium ion solution is not less than 15%.

8. The preparation method of the anti-carbonization solid waste slag-sulfoaluminate cementitious material according to claim 6, characterized in that, The magnesium ion solution includes at least one of magnesium chloride solution, magnesium sulfate solution, and magnesium nitrate solution. Alternatively, the alkaline solution may include at least one of sodium hydroxide solution, potassium hydroxide solution, and ammonia solution; Alternatively, the calcination treatment is carried out at a temperature of 560~630℃ for 2~2.5 hours.

9. The preparation method of the anti-carbonization all-solid waste slag-sulfoaluminate cementitious material according to claim 6, characterized in that, The proportion of the anti-carbonation reinforcing agent is 14-20% of the total amount of blast furnace slag powder, modified sulfoaluminate cement and fly ash; or, the fineness of the anti-carbonation reinforcing agent is not less than 300 mesh.

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