A solidification method and solidification agent based on total solid waste wet carbonization

Abstract

The application discloses a solidification method based on full solid waste wet carbonization, which comprises the following steps: (1) solidification agent preparation: calcium solid waste and siliceous solid waste are dried to constant weight, and then crushed to a required particle size for standby use; the calcium solid waste, the siliceous solid waste and an additive are weighed and placed in a stirring pot, and then stirred uniformly to prepare a solidification agent; (2) solidification: the solidification agent is added into soft soil and mixed uniformly, and the solidification agent becomes a solidification slurry with a water content of 40-65%; CO2 is introduced into the solidification slurry and stirred uniformly; then, the solidification slurry is cast and formed, and after the solidification slurry is hardened, the solidification slurry is demolded and moved to a standard curing box for curing until a curing age, so that the solidified soil is obtained. The application further discloses a solidification agent based on full solid waste wet carbonization. The application greatly improves the utilization rate of solid waste resources, and solves the problem that the prior art depends on cement.

Description

Technical Field

[0001] This invention belongs to the field of building technology, and specifically relates to a curing method and curing agent based on wet carbonization of all solid waste. Background Technology

[0002] Traditional solidifying agents mainly consist of inorganic materials such as cement and lime, offering advantages such as high strength, rapid hardening speed, and wide adaptability. However, due to their reliance on cement, traditional solidifying agents are increasingly revealing their disadvantages of high energy consumption, high pollution, and high economic costs. Meanwhile, the generation and stockpiling of industrial solid waste in my country are increasing year by year, with low resource utilization rates and stockpiling as the primary disposal method, posing significant potential environmental risks. In recent years, solid waste-based solidifying agents, i.e., solid waste-based solidifying agents, have become a research hotspot in the field of solid waste treatment, possessing the unique advantage of "treating waste with waste." However, existing solid waste-based solidifying agents, such as those disclosed in Chinese patents CN103013526A and CN120423843A, while utilizing industrial solid waste, still require large doses of cement to provide basic cementing effects; that is, the problems of high energy consumption, high pollution, and high economic costs associated with cement persist.

[0003] Currently, research on solid waste-based solidifiers mainly focuses on activating gelling activity (generally through mechanical grinding and chemical activation) to improve the workability, mechanical properties, and impermeability of solidified soil. These solidifiers are widely used in foundation pit backfilling, mine backfilling, soft soil foundation reinforcement, and sludge solidification. Existing research indicates that some high-calcium solid wastes exhibit high carbonation activity under suitable wet or semi-dry conditions, capable of reacting with CO2 to form calcium carbonate. Applying these solid waste carbonation characteristics to solidifiers could achieve the dual benefits of increasing solid waste utilization and promoting carbon emission reduction, representing a highly promising green technology. Summary of the Invention

[0004] One of the objectives of this invention is to provide a solidification method based on wet carbonization of all solid waste, which significantly improves the utilization rate of solid waste resources and solves the problem of existing technologies relying on cement.

[0005] The second objective of this invention is to provide a curing agent based on wet carbonization of all solid waste.

[0006] To achieve the above objectives, the present invention adopts the following technical solution.

[0007] A solidification method based on wet carbonization of all solid waste, characterized by comprising the following steps:

[0008] (1) Preparation of curing agent: Dry the calcium solid waste and silicon solid waste to constant weight, and crush them to the required particle size for later use; weigh the calcium solid waste, silicon solid waste and additives and place them in a mixing pot, stir evenly to obtain the curing agent;

[0009] (2) Curing: Add the curing agent to the soft soil and mix it evenly to make it into a cured slurry with a water content of 40-65%; introduce CO2 into the cured slurry and stir evenly; then pour it into shape, and after the cured slurry hardens, demold it and transfer it to a standard curing box for curing until the desired age, thus obtaining the cured soil.

[0010] This invention injects CO2 into the solidification slurry during the solidification step. CO2 is soluble in water and can also be stored in the slurry pores, significantly increasing the available carbon source. In the solidified slurry, calcareous solid waste comes into full contact with CO2, increasing the carbonization reaction rate, and the carbonization products fill the slurry pores, providing initial strength. The carbonization reaction is exothermic, raising the temperature of the solidified slurry and promoting the pozzolanic reaction of siliceous solid waste under the action of an activator, enhancing the later strength of the solidified soil. Through these two chemical reactions, the mechanical properties of the solidified soil are significantly improved, solving the problem of existing solidification technologies relying on cement. Furthermore, the carbonization reaction is 80% completed within 24 hours of pouring, rapidly increasing the strength of the solidified soil, thus improving the solidification efficiency.

[0011] The calcium-based solid waste described in this invention is at least one of steel slag, refining slag, phosphogypsum, and calcium carbide slag. Steel slag is an industrial waste generated during the iron and steel smelting process, with an f-CaO content generally of 4-9% and an f-MgO content generally of 3-5%. Refining slag is waste generated from nickel-iron alloy smelting plants, with a CaO mineral content higher than 50% and an alkalinity higher than 1.8. Phosphogypsum is an industrial byproduct generated during the wet-process phosphoric acid production process, with a calcium sulfate dihydrate content higher than 95% and a water-soluble phosphorus content lower than 0.5%. Calcium carbide slag is waste generated during the acetylene production process from calcium carbide, with a calcium hydroxide content higher than 90%. All of the above-mentioned calcium-based solid waste must be crushed to a particle size not exceeding 0.15 mm.

[0012] The siliceous solid waste described in this invention is at least one of silica fume, fly ash, slag, and yellow phosphorus slag; wherein, silica fume is waste residue discharged during ferroalloy smelting, with an SiO2 content higher than 90%; fly ash is industrial waste discharged from power plants, with an SiO2 content higher than 50%; slag is waste residue generated during blast furnace ironmaking, with an SiO2 content of not less than 35%; and yellow phosphorus slag is industrial waste generated during the production of yellow phosphorus by electric furnace, with an SiO2 content higher than 40%. The aforementioned siliceous solid waste needs to be pulverized to a particle size not exceeding 45 μm.

[0013] Preferably, the amount of calcareous solid waste added is 40-70% of the total mass of solid waste, and the amount of siliceous solid waste added is 30-60% of the total mass of solid waste; the total mass of solid waste is the total mass of calcareous solid waste and siliceous solid waste. Different addition amounts can be used to adjust the intensity according to the actual application scenario.

[0014] The admixtures described in this invention include a carbonization enhancer and a gelling activity activator. Preferably, the carbonization enhancer is one of ammonium chloride, acetic acid, or a chelating agent, and its dosage is 3% to 8% of the calcareous solid waste, mainly to increase the amount of calcium ions dissolved in the calcareous solid waste. The gelling activity activator is one of an alkali, a carbonate, or a sulfate, and its dosage is 2% to 5% of the siliceous solid waste, mainly to activate the pozzolanic activity of the siliceous solid waste.

[0015] Preferably, in step (1), the stirring time is 3 to 5 minutes.

[0016] Preferably, in step (2), the moisture content of the soft soil is about 50% to 70%, and the amount of solidifying agent is 10% to 20% of the mass of the soft soil.

[0017] Preferably, in step (2), CO2 with a concentration of 20% (volume fraction) is introduced into the fluidized solidified soil; the CO2 injection pressure needs to be controlled at 0.1 to 0.3 MPa, and the injection time is 1 to 3 min.

[0018] Preferably, in step (2), the maintenance period is 7 days.

[0019] The present invention also provides a curing agent based on wet carbonization of all solid waste, comprising: calcareous solid waste, siliceous solid waste, and additives; wherein the amount of calcareous solid waste is 40-70% of the total mass of solid waste, and the amount of siliceous solid waste is 30-60% of the total mass of solid waste; wherein the additives include carbonization enhancers and gelation activators.

[0020] The calcium-based solid waste is at least one of steel slag, refining slag, phosphogypsum, and carbide slag.

[0021] The siliceous solid waste is at least one of silica fume, fly ash, and yellow phosphorus slag.

[0022] The carbonization enhancer is one of ammonium chloride, acetic acid, or chelating agent, and its dosage is 3% to 8% of the calcium solid waste.

[0023] The gelling activator is one of the following: alkali, carbonate, or sulfate, and its dosage is 2% to 5% of the siliceous solid waste.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] (1) This invention improves the performance of solidified soil by increasing the wet carbonization activity of calcareous solid waste and stimulating the gelation activity of high silica solid waste. First, calcium ions in the initial calcareous solid waste dissolve in a weakly acidic environment (CO2 dissolves in water to form a weakly acidic environment) and react with CO2 dissolved in the system to carbonize, providing initial strength for the solidified soil. Second, silica solid waste undergoes a pozzolanic reaction under the action of an activator, further enhancing the later strength of the solidified soil. In summary, this invention can make the mechanical properties of the solidified soil better than those of conventionally solidified soil with cement added, without the addition of cement.

[0026] (2) This invention realizes the high-value utilization of solid waste and the solidification and storage of carbon dioxide, and greatly reduces the amount of cement used and energy consumption. It is in line with the carbon emission reduction policy and is of great significance to environmental protection and resource utilization. This invention can be widely applied to the fields of soft foundation solidification, foundation pit backfilling, engineering backfilling, and road base treatment.

[0027] (3) The method of the present invention utilizes the combination of wet carbonization of solid waste and gelation activity activation to improve solidification efficiency.

[0028] (4) The curing agent of the present invention combines solid waste wet carbonization and gelation activity activation technology to achieve the dual goals of "carbon emission reduction" and low carbon gelation material preparation, making it both efficient, environmentally friendly and resource-valued; moreover, the curing agent has a simple preparation process, low cost and low energy consumption, and can be applied to the fields of soft foundation curing and foundation pit backfilling. Detailed Implementation

[0029] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0030] Example 1

[0031] The curing agent in this embodiment is composed of: calcareous solid waste: 20% steel slag, 20% phosphogypsum; siliceous solid waste: 60% silica fume; admixtures: ammonium chloride is calculated as 3% of the total mass of steel slag and phosphogypsum waste, sodium hydroxide is calculated as 1% of the mass of silica fume, and sodium sulfate is calculated as 1% of the mass of silica fume.

[0032] The solidification method based on wet carbonization of all solid waste is operated as follows:

[0033] (1) Preparation of curing agent: Calcium solid waste and silicon solid waste are dried at 105±5℃ to constant weight; calcium solid waste is crushed to a particle size not higher than 0.15mm and silicon solid waste is crushed to a particle size not higher than 45μm;

[0034] According to the above proportions, weigh appropriate amounts of calcareous solid waste, siliceous solid waste, and additives and place them in a mixing pot. Stir evenly for about 3 minutes to obtain a curing agent.

[0035] (2) Solidification: Weigh an appropriate amount of soft soil with a moisture content of about 50%. Add the solidifying agent at 10% of the total mass of the soft soil and mix it evenly to make it a solidified slurry with a moisture content of up to 45%. Introduce 20% CO2 into the solidified slurry and stir evenly. The CO2 injection pressure should be controlled at 0.1 MPa and the injection time is 3 minutes. Then pour it into a 70.7mm×70.7mm×70.7mm mold, vibrate and scrape the surface, cover it with plastic film for 24 hours, and demold it after the solidified slurry has hardened. Transfer it to a standard curing box and cure it for 3 days and 7 days. Then conduct relevant performance tests on the solidified soil.

[0036] The solidified soil specimens were tested for 3-day and 7-day unconfined compressive strength according to GB / T 50081 "Standard for Test Methods of Physical and Mechanical Properties of Concrete"; the permeability coefficient of the solidified soil was tested according to GB / T 50123 "Standard for Geotechnical Test Methods".

[0037] Example 2

[0038] The curing agent in this embodiment is composed of: calcareous solid waste: 20% steel slag, 30% refining slag; siliceous solid waste: 50% fly ash; additives: acetic acid is calculated as 5% of the total mass of steel slag and refining slag, and sodium carbonate is calculated as 3% of the mass of fly ash.

[0039] The solidification method based on wet carbonization of all solid waste is operated as follows:

[0040] (1) Preparation of curing agent: Calcium solid waste and silicon solid waste are dried at 105±5℃ to constant weight; calcium solid waste is crushed to a particle size not higher than 0.15mm and silicon solid waste is crushed to a particle size not higher than 45μm;

[0041] According to the above proportions, weigh appropriate amounts of calcareous solid waste, siliceous solid waste, and additives and place them in a mixing pot. Stir evenly for about 4 minutes to obtain a curing agent.

[0042] (2) Solidification: Weigh an appropriate amount of soft soil with a moisture content of about 55%. Add the solidifying agent at 13% of the total mass of the soft soil and mix it evenly to make it a solidified slurry with a moisture content of up to 48%. Introduce 20% CO2 into the solidified slurry and stir evenly. The CO2 injection pressure should be controlled at 0.2MPa and the injection time is 2min. Then pour it into a 70.7mm×70.7mm×70.7mm mold, vibrate and scrape the surface, cover it with plastic film for 24 hours, and demold it after the solidified slurry has hardened. Transfer it to a standard curing box and cure it for 3d and 7d. Then conduct relevant performance tests on the solidified soil.

[0043] The solidified soil specimens were tested for 3-day and 7-day unconfined compressive strength according to GB / T 50081 "Standard for Test Methods of Physical and Mechanical Properties of Concrete"; the permeability coefficient of the solidified soil was tested according to GB / T 50123 "Standard for Geotechnical Test Methods".

[0044] Example 3

[0045] The curing agent in this embodiment is composed of: calcareous solid waste: 50% steel slag, siliceous solid waste: 50% silica fume; additives: chelating agent is calculated as 7% of the mass of steel slag, and sodium carbonate is calculated as 3% of the mass of silica fume.

[0046] The solidification method based on wet carbonization of all solid waste is operated as follows:

[0047] (1) Preparation of curing agent: Dry the calcium solid waste and silicon solid waste at 105±5℃ to constant weight; crush the calcium solid waste to a particle size not higher than 0.15mm and the silicon solid waste to a particle size not higher than 45μm;

[0048] According to the above proportions, weigh out appropriate amounts of calcareous solid waste, siliceous solid waste, and additives and place them in a mixing pot. Stir evenly for about 5 minutes to obtain a curing agent.

[0049] (2) Solidification: Weigh an appropriate amount of soft soil with a moisture content of about 58%. Add the solidifying agent at 15% of the total mass of the soft soil and mix it evenly to make it a solidified slurry with a moisture content of up to 50%. Introduce 20% CO2 into the solidified slurry and stir evenly. The CO2 injection pressure should be controlled at 0.3MPa and the injection time is 1min. Then pour it into a 70.7mm×70.7mm×70.7mm mold, vibrate and scrape the surface, cover it with plastic film for 24 hours, and demold it after the solidified slurry has hardened. Transfer it to a standard curing box and cure it for 3 days and 7 days. Then conduct relevant performance tests on the solidified soil.

[0050] The solidified soil specimens were tested for 3-day and 7-day unconfined compressive strength according to GB / T 50081 "Standard for Test Methods of Physical and Mechanical Properties of Concrete"; the permeability coefficient of the solidified soil was tested according to GB / T 50123 "Standard for Geotechnical Test Methods".

[0051] Example 4

[0052] The curing agent in this embodiment is composed of: calcareous solid waste: 40% steel slag and 30% carbide slag; siliceous solid waste: 15% silica fume and 15% yellow phosphorus slag; and additives: ammonium chloride is calculated as 8% of the total mass of steel slag and carbide slag, and sodium carbonate is calculated as 4% of the total mass of silica fume and yellow phosphorus slag.

[0053] The solidification method based on wet carbonization of all solid waste is operated as follows:

[0054] (1) Preparation of curing agent: Calcium solid waste and silicon solid waste are dried at 105±5℃ to constant weight; calcium solid waste is crushed to a particle size not higher than 0.15mm and silicon solid waste is crushed to a particle size not higher than 45μm;

[0055] According to the above proportions, weigh appropriate amounts of calcareous solid waste, siliceous solid waste, and additives and place them in a mixing pot. Stir evenly for about 3 minutes to obtain a curing agent.

[0056] (2) Solidification: Weigh an appropriate amount of soft soil with a moisture content of about 65%. Add the solidifying agent at 17% of the total mass of the soft soil and mix it evenly to make it a solidified slurry with a moisture content of up to 55%. Introduce 20% CO2 into the solidified slurry and stir evenly. The CO2 injection pressure should be controlled at 0.3MPa and the injection time is 2min. Then pour it into a 70.7mm×70.7mm×70.7mm mold, vibrate and scrape the surface, cover it with plastic film for 24 hours, and demold it after the solidified slurry has hardened. Transfer it to a standard curing box and cure it for 3 days and 7 days. Then conduct relevant performance tests on the solidified soil.

[0057] The solidified soil specimens were tested for 3-day and 7-day unconfined compressive strength according to GB / T 50081 "Standard for Test Methods of Physical and Mechanical Properties of Concrete"; the permeability coefficient of the solidified soil was tested according to GB / T 50123 "Standard for Geotechnical Test Methods".

[0058] Example 5

[0059] The curing agent in this embodiment is composed of: 70% calcium carbide slag and 30% siliceous solid waste; and additives: 4% acetic acid by mass of total calcium carbide slag, 2% sodium hydroxide by mass of fly ash, and 3% sodium sulfate by mass of fly ash.

[0060] The solidification method based on wet carbonization of all solid waste is operated as follows:

[0061] (1) Preparation of curing agent: Calcium solid waste and silicon solid waste are dried at 105±5℃ to constant weight; calcium solid waste is crushed to a particle size not higher than 0.15mm and silicon solid waste is crushed to a particle size not higher than 45μm;

[0062] According to the above proportions, weigh out appropriate amounts of calcareous solid waste, siliceous solid waste, and additives and place them in a mixing pot. Stir evenly for about 5 minutes to obtain a curing agent.

[0063] (2) Solidification: Weigh an appropriate amount of soft soil with a moisture content of about 70%. Add the solidifying agent at 19% of the total mass of the soft soil and mix it evenly to make it a solidified slurry with a moisture content of up to 60%. Introduce 20% CO2 into the solidified slurry and stir evenly. The CO2 injection pressure should be controlled at 0.2MPa and the injection time is 3min. Then pour it into a 70.7mm×70.7mm×70.7mm mold, vibrate and scrape the surface, cover it with plastic film for 24 hours, and demold it after the solidified slurry has hardened. Transfer it to a standard curing box and cure it for 3d and 7d. Then conduct relevant performance tests on the solidified soil.

[0064] The solidified soil specimens were tested for 3-day and 7-day unconfined compressive strength according to GB / T 50081 "Standard for Test Methods of Physical and Mechanical Properties of Concrete"; the permeability coefficient of the solidified soil was tested according to GB / T 50123 "Standard for Geotechnical Test Methods".

[0065] Example 6

[0066] The curing agent in this embodiment is composed of: calcareous solid waste: 50% carbide slag, 10% yellow phosphorus slag; siliceous solid waste: 40% silica fume; additives: chelating agent is calculated as 6% of the total mass of carbide slag and yellow phosphorus slag, and sodium carbonate is calculated as 3% of the mass of silica fume.

[0067] The solidification method based on wet carbonization of all solid waste is operated as follows:

[0068] (1) Preparation of curing agent: Calcium solid waste and silicon solid waste are dried at 105±5℃ to constant weight; calcium solid waste is crushed to a particle size not higher than 0.15mm and silicon solid waste is crushed to a particle size not higher than 45μm;

[0069] According to the above proportions, weigh out appropriate amounts of calcareous solid waste, siliceous solid waste, and additives and place them in a mixing pot. Stir evenly for about 5 minutes to obtain a curing agent.

[0070] (3) Solidification: Weigh an appropriate amount of soft soil with a moisture content of about 78%. Add the solidifying agent at 20% of the total mass of the soft soil and mix it evenly to make it a solidified slurry with a moisture content of up to 65%. Introduce 20% CO2 into the fluid solidified soil and stir evenly. The CO2 injection pressure should be controlled at 0.3MPa and the injection time is 3min. Then pour it into a 70.7mm×70.7mm×70.7mm mold, vibrate and scrape the surface, cover it with plastic film for 24 hours, and demold it after the solidified slurry has hardened. Transfer it to a standard curing box and cure it for 3d and 7d. Then conduct relevant performance tests on the solidified soil.

[0071] The solidified soil specimens were tested for 3-day and 7-day unconfined compressive strength according to GB / T 50081 "Standard for Test Methods of Physical and Mechanical Properties of Concrete"; the permeability coefficient of the solidified soil was tested according to GB / T 50123 "Standard for Geotechnical Test Methods".

[0072] Comparative Example 1

[0073] The composition of this comparative curing agent is: 10% cement, 50% slag, and 40% fly ash.

[0074] The specific steps for curing are as follows:

[0075] (1) Preparation of curing agent: Cement, slag and fly ash are dried at 105±5℃ to constant weight and crushed to a particle size of less than 80μm for later use;

[0076] According to the above proportions, weigh out appropriate amounts of cement, slag and fly ash and place them in a mixing pot, and mix them evenly; the mixing time is about 3 minutes to obtain the curing agent.

[0077] (2) Solidification: Weigh an appropriate amount of soft soil with a moisture content of about 66%. Add the solidifying agent at 20% of the total mass of the soft soil and mix it evenly to make it into a solidified slurry with a moisture content of up to 55%. Then pour the slurry into a 70.7mm×70.7mm×70.7mm mold, vibrate and scrape the surface, cover it with plastic film and cure for 24 hours. After the solidified slurry hardens, demold it and transfer it to a standard curing box for curing for 3 days and 7 days. Then conduct relevant performance tests on the solidified soil.

[0078] The solidified soil specimens were tested for 3-day and 7-day unconfined compressive strength according to GB / T 50081 "Standard for Test Methods of Physical and Mechanical Properties of Concrete"; the permeability coefficient of the solidified soil was tested according to GB / T 50123 "Standard for Geotechnical Test Methods".

[0079] Comparative Example 2

[0080] The curing agent in this embodiment is composed of: calcareous solid waste: 50% steel slag, 10% yellow phosphorus slag; siliceous solid waste: 40% fly ash; and admixture: sodium carbonate, calculated as 3% of the mass of silica ash.

[0081] The specific steps for curing are as follows:

[0082] (1) Preparation of curing agent: Calcium solid waste and silicon solid waste are dried at 105±5℃ to constant weight; calcium solid waste is crushed to a particle size not higher than 0.15mm and silicon solid waste is crushed to a particle size not higher than 45μm;

[0083] According to the above proportions, weigh out appropriate amounts of calcareous solid waste, siliceous solid waste, and additives and place them in a mixing pot. Stir evenly for about 5 minutes to obtain a curing agent.

[0084] (3) Solidification: Weigh an appropriate amount of soft soil with a moisture content of about 78%. Add the solidifying agent at 20% of the total mass of the soft soil and mix it evenly to make it a solidified slurry with a moisture content of up to 65%. Introduce 20% CO2 into the fluid solidified soil and stir evenly. The CO2 injection pressure should be controlled at 0.3MPa and the injection time is 3min. Then pour it into a 70.7mm×70.7mm×70.7mm mold, vibrate and scrape the surface, cover it with plastic film for 24 hours, and demold it after the solidified slurry has hardened. Transfer it to a standard curing box and cure it for 3d and 7d. Then conduct relevant performance tests on the solidified soil.

[0085] The solidified soil specimens were tested for 3-day and 7-day unconfined compressive strength according to GB / T 50081 "Standard for Test Methods of Physical and Mechanical Properties of Concrete"; the permeability coefficient of the solidified soil was tested according to GB / T 50123 "Standard for Geotechnical Test Methods".

[0086] Comparative Example 3

[0087] The curing agent in this embodiment is composed of: calcareous solid waste: 40% calcium carbide slag and 15% yellow phosphorus slag; siliceous solid waste: 40% silica fume; and additives: chelating agent, calculated as 5% of the total mass of calcium carbide slag and yellow phosphorus slag.

[0088] The specific steps for curing are as follows:

[0089] (1) Preparation of curing agent: Calcium solid waste and silicon solid waste are dried at 105±5℃ to constant weight; calcium solid waste is crushed to a particle size not higher than 0.15mm and silicon solid waste is crushed to a particle size not higher than 45μm;

[0090] According to the above proportions, weigh out appropriate amounts of calcareous solid waste, siliceous solid waste, and additives and place them in a mixing pot. Stir evenly for about 5 minutes to obtain a curing agent.

[0091] (3) Solidification: Weigh an appropriate amount of soft soil with a moisture content of about 78%. Add the solidifying agent at 20% of the total mass of the soft soil and mix it evenly to make it a solidified slurry with a moisture content of up to 65%. Introduce 20% CO2 into the fluid solidified soil and stir evenly. The CO2 injection pressure should be controlled at 0.3MPa and the injection time is 3min. Then pour it into a 70.7mm×70.7mm×70.7mm mold, vibrate and scrape the surface, cover it with plastic film for 24 hours, and demold it after the solidified slurry has hardened. Transfer it to a standard curing box and cure it for 3d and 7d. Then conduct relevant performance tests on the solidified soil.

[0092] The solidified soil specimens were tested for 3-day and 7-day unconfined compressive strength according to GB / T 50081 "Standard for Test Methods of Physical and Mechanical Properties of Concrete"; the permeability coefficient of the solidified soil was tested according to GB / T 50123 "Standard for Geotechnical Test Methods".

[0093] Comparative Example 4

[0094] The curing agent in this embodiment consists of: 60% calcareous solid waste (steel slag), 20% siliceous solid waste (silica fume), and 20% fly ash.

[0095] The specific steps for curing are as follows:

[0096] (1) Preparation of curing agent: Calcium solid waste and silicon solid waste are dried at 105±5℃ to constant weight; calcium solid waste is crushed to a particle size not higher than 0.15mm and silicon solid waste is crushed to a particle size not higher than 45μm;

[0097] According to the above proportions, weigh out appropriate amounts of calcareous solid waste and siliceous solid waste and place them in a mixing pot, and stir evenly; the stirring time is about 5 minutes to obtain the curing agent.

[0098] (3) Solidification: Weigh an appropriate amount of soft soil with a water content of about 69%. Add the solidifying agent at 15% of the total mass of the soft soil and mix it evenly to make it a solidified slurry with a water content of up to 60%. Then pour it into a 70.7mm×70.7mm×70.7mm mold, vibrate and scrape the surface, cover it with plastic film for 24 hours, and demold it after the solidified slurry has hardened. Then transfer it to a standard curing box for curing for 3 days and 7 days. After curing, conduct relevant performance tests on the solidified soil.

[0099] The solidified soil specimens were tested for 3-day and 7-day unconfined compressive strength according to GB / T 50081 "Standard for Test Methods of Physical and Mechanical Properties of Concrete"; the permeability coefficient of the solidified soil was tested according to GB / T 50123 "Standard for Geotechnical Test Methods".

[0100] The test results of the above embodiments and comparative examples are shown in Table 1:

[0101] Table 1

[0102]

[0103] The results in Table 1 show that the mechanical properties of the solidified soil prepared in Examples 1-6 are superior to those of the solidified soil conventionally mixed with cement in Comparative Example 1, and its seepage prevention performance is also better. As can be seen from the results of Comparative Examples 2-4, the solidifying agent does not contain carbonation reinforcing agents or cementitious activators, and CO2 is not introduced during solidification, thus failing to achieve the effects of this invention.

Claims

1. A solidification method based on wet carbonization of all solid waste, characterized in that, Includes the following steps: (1) Preparation of curing agent: Dry the calcareous solid waste and siliceous solid waste to constant weight, and crush them to the required particle size for later use; weigh the calcareous solid waste, siliceous solid waste and additives and place them in a mixing pot, stir evenly to obtain the curing agent; the additives include carbonization enhancer and gelation activator; (2) Curing: Add the curing agent to the soft soil and mix it evenly to make it into a cured slurry with a water content of 40-65%; introduce CO2 into the cured slurry and stir evenly; then pour it into shape, and after the cured slurry hardens, demold it and transfer it to a standard curing box for curing until the desired age, thus obtaining the cured soil.

2. The curing method according to claim 1, characterized in that, The calcareous solid waste is at least one of steel slag, refining slag, phosphogypsum, and carbide slag; the siliceous solid waste is at least one of silica fume, fly ash, slag, and yellow phosphorus slag.

3. The curing method according to claim 2, characterized in that, The amount of calcium-based solid waste added is calculated as 40-70% of the total mass of solid waste, and the amount of silicon-based solid waste added is calculated as 30-60% of the total mass of solid waste.

4. The curing method according to claim 3, characterized in that, The carbonization enhancer is one of ammonium chloride, acetic acid, and chelating agent, and its dosage is 3% to 8% of the calcium solid waste; the gelling activity activator is one of alkali, carbonate, and sulfate, and its dosage is 2% to 5% of the siliceous solid waste.

5. The curing method according to claim 4, characterized in that, In step (2), the moisture content of the soft soil is about 50% to 70%, and the amount of solidifying agent is 10% to 20% of the mass of the soft soil.

6. The curing method according to claim 5, characterized in that, The calcium-based solid waste is pulverized to a particle size not exceeding 0.15 mm; the silicon-based solid waste is pulverized to a particle size not exceeding 45 μm.

7. The curing method according to claim 6, characterized in that, in In step (2), CO2 with a concentration of 20% is introduced into the fluidized solidified soil; the CO2 injection pressure needs to be controlled at 0.1 to 0.3 MPa and the injection time is 1 to 3 minutes.

8. A curing agent based on wet carbonization of all solid waste, characterized in that, include: The mixture comprises calcareous solid waste, siliceous solid waste, and additives; the amount of calcareous solid waste is 40-70% of the total mass of the solid waste, and the amount of siliceous solid waste is 30-60% of the total mass of the solid waste; the additives include carbonization enhancers and gelation activators.

9. The curing agent according to claim 8, characterized in that, The carbonization enhancer is one of ammonium chloride, acetic acid, and chelating agent, and its dosage is 3% to 8% of the calcium solid waste; the gelling activity activator is one of alkali, carbonate, and sulfate, and its dosage is 2% to 5% of the siliceous solid waste.

10. The curing agent according to claim 9, characterized in that, The calcareous solid waste is at least one of steel slag, refining slag, phosphogypsum, and carbide slag; the siliceous solid waste is at least one of silica fume, fly ash, and yellow phosphorus slag.

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