Silicate-containing wastewater reinforced construction solid waste recycled aggregate and preparation method thereof

Abstract

The application discloses a kind of silicate-containing wastewater reinforced building solid waste recycled aggregate and preparation method thereof, and silicate-containing wastewater is used to reinforce building solid waste recycled aggregate.First, soak, silicate-containing wastewater and building solid waste recycled aggregate are placed in airtight mixing device, so that silicate-containing wastewater completely submerges building solid waste recycled aggregate 1-2cm, and soak treatment is carried out under normal temperature and pressure for 4-7h.Second, mix, CO2 gas is filled into airtight mixing device after first step soak treatment, and when pressure reaches 0.5-1.0MPa, mixing treatment is carried out under normal temperature and pressure for 36-60h.CO2 gas is supplemented every 4h during mixing treatment to ensure that the pressure in airtight mixing device is 0.5-1.0MPa, and the rotation speed of airtight mixing device is 25-35r / min.Third, clean, silicate-containing wastewater in airtight mixing device after second step mixing treatment is discharged, and building solid waste recycled aggregate is washed with clean water.Fourth, dry, building solid waste recycled aggregate after third step cleaning treatment is discharged, and is dried or naturally dried to obtain silicate-containing wastewater reinforced building solid waste recycled aggregate.

Description

Technical Field

[0001] This invention belongs to the field of building materials technology, specifically relating to a recycled aggregate for building solid waste reinforced with silicate wastewater and its preparation method. Background Technology

[0002] The amount of construction solid waste discharged in my country has been increasing year by year. Currently, most of the construction solid waste is landfilled or stockpiled. On the other hand, the demand for sand and gravel aggregates in the construction industry is constantly increasing. The over-exploitation of natural stone has led to resource depletion, landslides, riverbed changes, and damage to the natural environment.

[0003] Currently, reusing construction solid waste by crushing, screening, sorting, and cleaning it to produce recycled aggregate is an effective means of compensating for resource depletion. However, recycled aggregate obtained through mechanical crushing suffers from defects such as numerous microcracks, high water absorption, and poor quality, limiting its direct application. Strengthening and modifying it is therefore an important method. Methods for strengthening recycled aggregate include: physical strengthening (mainly mechanical grinding), chemical strengthening (mainly soaking in chemical slurries), and nano-strengthening (mainly filling with nanomaterials). Physical strengthening typically requires specialized machinery, making the operation complex and offering limited performance improvements to recycled aggregates. Chemical strengthening causes significant environmental pollution and has limited effectiveness. Nano-strengthening offers better application results and overall benefits. It utilizes the micro-aggregate effect of nanomaterials to fill surface and internal cracks in recycled aggregates. Furthermore, nanomaterials are highly reactive and can undergo secondary hydration reactions with Ca(OH)2 enriched in the pores of the old cement paste interface. The resulting CSH gel can fully fill the pores and improve the old cement paste interface. Among these methods, nano-SiO2 strengthening is particularly effective. However, this method is not economical, and there is room for improvement in its modification effect.

[0004] Currently, the use of newly formulated nano-strengthening liquids results in additional material waste and environmental pollution, and single-method strengthening treatments offer very limited performance improvements to recycled aggregates. Finding a technology with practical application value in terms of both economy and performance is key to solving the problem of recycled aggregate strengthening. The chemical industry generates large amounts of high-pH silicate-containing wastewater during production. Commonly used water treatment agents such as polyaluminum chloride (PAC), polyacrylamide (PAM), and polyacrylic acid are ineffective or have very poor effects on removing suspended solids from this wastewater, making treatment difficult. Systematic reports on the treatment of this type of wastewater have not yet been found. This application demonstrates that this silicate-containing wastewater, through certain technical means, has a significant strengthening effect on recycled aggregates from construction solid waste.

[0005] In their study, "Research on the Modification of Recycled Coarse Aggregate Properties by Chemical Fortification," Wei Hongjun et al. clarified the strengthening effects of nano-SiO2 and sodium silicate on recycled coarse aggregate. After treatment with optimal strengthening conditions using nano-SiO2 and sodium silicate, the water absorption rate of the recycled coarse aggregate decreased by 29.9% and 16.4%, respectively, and the crushing index decreased by 29.7% and 16.4%, respectively. The apparent density and bulk density were improved, approaching the levels of natural aggregate. The strengthening effect was in the order of nano-SiO2 > sodium silicate. Chinese Patent (CN202211359790.3) discloses a method for strengthening recycled aggregate, employing a "three-treatment method": first, acid soaking chemical treatment; then, autoclaving treatment; and finally, ball milling mechanical treatment. This "three-treatment method" significantly improves the physical properties and inherent strength of the recycled aggregate. However, "acid soaking" increases environmental and equipment costs, making it impractical. Chinese patent (CN202211422984.3) discloses a method for rapid carbonization of recycled aggregate from construction waste based on organic amines, which "uses organic amines to fix CO2 and improve the carbonization rate of recycled aggregates." Organic amines have significant advantages due to their chemical bonding, as they can react chemically with both recycled aggregates and CO2 in the environment. However, the application of organic amines increases the processing cost of recycled aggregates and does not have significant economic application value. Chinese patent (CN202211030326.X) discloses a method for strengthening recycled aggregates using a composite of nano-dispersion and chemical solution, which uses nano-SiO2 and calcium hydroxide to strengthen recycled aggregates (nano-dispersion and chemical solution composite strengthening). Although the strengthening effect is relatively obvious, it still uses newly configured strengthening materials and does not have a significant cost advantage. Summary of the Invention

[0006] The purpose of this invention is to provide a recycled aggregate from construction solid waste enhanced with silicate wastewater, characterized by using silicate wastewater to enhance the recycled aggregate from construction solid waste.

[0007] Furthermore, the silicate-containing wastewater is silicate-containing wastewater generated during chemical production, with a pH value of 12-14, and the silicate content is 15-20 g / L (calculated as SiO2); the recycled aggregate from construction solid waste is recycled stone material formed after waste concrete blocks are crushed, screened, washed, and dried.

[0008] A method for preparing recycled aggregate from construction solid waste enhanced with silicate wastewater includes the following steps:

[0009] The first step is soaking. Silicate-containing wastewater and recycled aggregate from construction solid waste are placed in a closed mixing device, so that the silicate-containing wastewater completely submerges the recycled aggregate from construction solid waste by 1-2 cm. Soaking is carried out for 4-7 hours under normal temperature and pressure.

[0010] The second step is mixing. CO2 gas is introduced into the sealed mixing device after the first soaking treatment. When the pressure reaches 0.5-1.0 MPa, the mixing treatment is carried out at room temperature and pressure for 36-60 hours. During the mixing treatment, CO2 gas is added every 4 hours to ensure that the pressure in the sealed mixing device is 0.5-1.0 MPa. The rotation speed of the sealed mixing device is 25-35 r / min.

[0011] The third step is cleaning. The silicate-containing wastewater in the closed mixing device after the second step of mixing is discharged, and the recycled aggregate from construction solid waste is rinsed with clean water.

[0012] The fourth step is drying. The recycled aggregate from the construction solid waste that has been cleaned in the third step is released and dried by baking or air drying to obtain recycled aggregate from construction solid waste reinforced with silicate wastewater.

[0013] Compared with the prior art, the present invention has the following advantages.

[0014] First, it is economical and environmentally friendly: using silicate-containing wastewater to treat construction solid waste and recycled aggregates strengthens the recycled aggregates while reducing the harmfulness of the wastewater. This saves wastewater generating units the cost of wastewater storage and treatment, and also saves recycled aggregate production units the cost of purchasing strengthening raw materials. It cleverly combines the two types of waste, allowing them to play their respective values, reducing the pollution of waste to the environment, and creating new value.

[0015] Second, composite reinforcement: Utilizing recycled aggregates from construction solid waste treated with silicate-containing wastewater, this innovative approach combines silicate reinforcement with silica reinforcement, employing both atmospheric and pressurized reinforcement to effectively improve the application performance of the recycled aggregates. The water absorption rate of the recycled aggregates can be increased by up to approximately 65.6%, the crushing value by up to approximately 30.6%, the apparent density by up to approximately 1.3%, and the bulk density by up to approximately 9.8%. Detailed Implementation

[0016] Example 1

[0017] The silicate-containing wastewater-enhanced recycled aggregate for construction solid waste described in this embodiment is obtained by using silicate-containing wastewater to enhance the recycled aggregate for construction solid waste.

[0018] Furthermore, the silicate-containing wastewater is silicate-containing wastewater generated during chemical production, with a pH value of 12, and the silicate content is 15 g / L as SiO2; the recycled aggregate from construction solid waste is recycled stone material formed after waste concrete blocks are crushed, screened, washed, and dried.

[0019] The method for preparing recycled aggregate from construction solid waste reinforced with silicate wastewater in this embodiment includes the following steps:

[0020] The first step is soaking. Silicate-containing wastewater and recycled aggregate from construction solid waste are placed in a closed mixing device, and the silicate-containing wastewater completely submerges the recycled aggregate from construction solid waste by 1-2 cm. The soaking treatment is carried out for 4 hours under normal temperature and pressure.

[0021] The second step is mixing. CO2 gas is introduced into the sealed mixing device after the first soaking treatment. When the pressure reaches 0.5 MPa, the device is mixed for 36 hours under normal temperature and pressure. During the mixing treatment, CO2 gas is added every 4 hours to ensure that the pressure in the sealed mixing device is 0.5 MPa. The rotation speed of the sealed mixing device is 25 r / min.

[0022] The third step is cleaning. The silicate-containing wastewater in the closed mixing device after the second step of mixing is discharged, and the recycled aggregate from construction solid waste is rinsed with clean water.

[0023] The fourth step is drying. The recycled aggregate from the construction solid waste that has been cleaned in the third step is released and dried by baking or air drying to obtain recycled aggregate from construction solid waste reinforced with silicate wastewater.

[0024] Example 2

[0025] This embodiment describes a silicate-containing wastewater-enhanced recycled aggregate for construction solid waste, which involves using silicate-containing wastewater to enhance the recycled aggregate.

[0026] Furthermore, the silicate-containing wastewater is silicate-containing wastewater generated during chemical production, with a pH value of 13, and the silicate content is 18 g / L as SiO2; the recycled aggregate from construction solid waste is recycled stone material formed after waste concrete blocks are crushed, screened, washed, and dried.

[0027] The method for preparing recycled aggregate from construction solid waste reinforced with silicate wastewater in this embodiment includes the following steps:

[0028] The first step is soaking. Silicate-containing wastewater and recycled aggregate from construction solid waste are placed in a closed mixing device, and the silicate-containing wastewater completely submerges the recycled aggregate from construction solid waste by 1-2 cm. The soaking treatment is carried out for 4 hours under normal temperature and pressure.

[0029] The second step is mixing. CO2 gas is introduced into the sealed mixing device after the first soaking treatment. When the pressure reaches 0.5 MPa, the device is mixed at room temperature and pressure for 38 hours. During the mixing treatment, CO2 gas is added every 4 hours to ensure that the pressure in the sealed mixing device is 0.5 MPa and the rotation speed of the sealed mixing device is 28 r / min.

[0030] The third step is cleaning. The silicate-containing wastewater in the closed mixing device after the second step of mixing is discharged, and the recycled aggregate from construction solid waste is rinsed with clean water.

[0031] The fourth step is drying. The recycled aggregate from the construction solid waste that has been cleaned in the third step is released and dried by baking or air drying to obtain recycled aggregate from construction solid waste reinforced with silicate wastewater.

[0032] Example 3

[0033] This embodiment describes a silicate-containing wastewater-enhanced recycled aggregate for construction solid waste, which involves using silicate-containing wastewater to enhance the recycled aggregate.

[0034] Furthermore, the silicate-containing wastewater is silicate-containing wastewater generated during chemical production, with a pH value of 12, and the silicate content is 17 g / L as SiO2; the recycled aggregate from construction solid waste is recycled stone material formed after waste concrete blocks are crushed, screened, washed, and dried.

[0035] The method for preparing recycled aggregate from construction solid waste reinforced with silicate wastewater in this embodiment includes the following steps:

[0036] The first step is soaking. Silicate-containing wastewater and recycled aggregate from construction solid waste are placed in a closed mixing device, and the silicate-containing wastewater completely submerges the recycled aggregate from construction solid waste by 1-2 cm. The soaking treatment is carried out at normal temperature and pressure for 4.5 hours.

[0037] The second step is mixing. CO2 gas is introduced into the sealed mixing device after the first soaking treatment. When the pressure reaches 0.6 MPa, the mixing treatment is carried out at room temperature and pressure for 40 hours. During the mixing treatment, CO2 gas is added every 4 hours to ensure that the pressure in the sealed mixing device is 0.6 MPa. The rotation speed of the sealed mixing device is 30 r / min.

[0038] The third step is cleaning. The silicate-containing wastewater in the closed mixing device after the second step of mixing is discharged, and the recycled aggregate from construction solid waste is rinsed with clean water.

[0039] The fourth step is drying. The recycled aggregate from the construction solid waste that has been cleaned in the third step is released and dried by baking or air drying to obtain recycled aggregate from construction solid waste reinforced with silicate wastewater.

[0040] Example 4

[0041] This embodiment describes a silicate-containing wastewater-enhanced recycled aggregate for construction solid waste, which involves using silicate-containing wastewater to enhance the recycled aggregate.

[0042] Furthermore, the silicate-containing wastewater is silicate-containing wastewater generated during chemical production, with a pH value of 14, and the silicate content is 16 g / L as SiO2; the recycled aggregate from construction solid waste is recycled stone material formed after waste concrete blocks are crushed, screened, washed, and dried.

[0043] The method for preparing recycled aggregate from construction solid waste reinforced with silicate wastewater in this embodiment includes the following steps:

[0044] The first step is soaking. Silicate-containing wastewater and recycled aggregate from construction solid waste are placed in a closed mixing device, and the silicate-containing wastewater completely submerges the recycled aggregate from construction solid waste by 1-2 cm. The soaking treatment is carried out for 5 hours under normal temperature and pressure.

[0045] The second step is mixing. CO2 gas is introduced into the sealed mixing device after the first soaking treatment. When the pressure reaches 0.6 MPa, the device is mixed at room temperature and pressure for 42 hours. During the mixing treatment, CO2 gas is added every 4 hours to ensure that the pressure in the sealed mixing device is 0.6 MPa. The rotation speed of the sealed mixing device is 35 r / min.

[0046] The third step is cleaning. The silicate-containing wastewater in the closed mixing device after the second step of mixing is discharged, and the recycled aggregate from construction solid waste is rinsed with clean water.

[0047] The fourth step is drying. The recycled aggregate from the construction solid waste that has been cleaned in the third step is released and dried by baking or air drying to obtain recycled aggregate from construction solid waste reinforced with silicate wastewater.

[0048] Example 5

[0049] This embodiment describes a silicate-containing wastewater-enhanced recycled aggregate for construction solid waste, which involves using silicate-containing wastewater to enhance the recycled aggregate.

[0050] Furthermore, the silicate-containing wastewater is silicate-containing wastewater generated during chemical production, with a pH value of 13, and the silicate content is 15 g / L as SiO2; the recycled aggregate from construction solid waste is recycled stone material formed after waste concrete blocks are crushed, screened, washed, and dried.

[0051] The method for preparing recycled aggregate from construction solid waste reinforced with silicate wastewater in this embodiment includes the following steps:

[0052] The first step is soaking. Silicate-containing wastewater and recycled aggregate from construction solid waste are placed in a closed mixing device, and the silicate-containing wastewater completely submerges the recycled aggregate from construction solid waste by 1-2 cm. The soaking treatment is carried out for 5 hours under normal temperature and pressure.

[0053] The second step is mixing. CO2 gas is introduced into the sealed mixing device after the first soaking treatment. When the pressure reaches 0.7 MPa, the device is mixed at room temperature and pressure for 45 hours. During the mixing treatment, CO2 gas is added every 4 hours to ensure that the pressure in the sealed mixing device is 0.7 MPa. The rotation speed of the sealed mixing device is 26 r / min.

[0054] The third step is cleaning. The silicate-containing wastewater in the closed mixing device after the second step of mixing is discharged, and the recycled aggregate from construction solid waste is rinsed with clean water.

[0055] The fourth step is drying. The recycled aggregate from the construction solid waste that has been cleaned in the third step is released and dried by baking or air drying to obtain recycled aggregate from construction solid waste reinforced with silicate wastewater.

[0056] Example 6

[0057] This embodiment describes a silicate-containing wastewater-enhanced recycled aggregate for construction solid waste, which involves using silicate-containing wastewater to enhance the recycled aggregate.

[0058] Furthermore, the silicate-containing wastewater is silicate-containing wastewater generated during chemical production, with a pH value of 13, and the silicate content is 17 g / L as SiO2; the recycled aggregate from construction solid waste is recycled stone material formed after waste concrete blocks are crushed, screened, washed, and dried.

[0059] The method for preparing recycled aggregate from construction solid waste reinforced with silicate wastewater in this embodiment includes the following steps:

[0060] The first step is soaking. Silicate-containing wastewater and recycled aggregate from construction solid waste are placed in a closed mixing device, so that the silicate-containing wastewater completely submerges the recycled aggregate from construction solid waste by 1-2 cm. The soaking treatment is carried out at normal temperature and pressure for 5.5 hours.

[0061] The second step is mixing. CO2 gas is introduced into the sealed mixing device after the first soaking treatment. When the pressure reaches 0.7 MPa, the device is mixed at room temperature and pressure for 48 hours. During the mixing treatment, CO2 gas is added every 4 hours to ensure that the pressure in the sealed mixing device is 0.7 MPa. The rotation speed of the sealed mixing device is 29 r / min.

[0062] The third step is cleaning. The silicate-containing wastewater in the closed mixing device after the second step of mixing is discharged, and the recycled aggregate from construction solid waste is rinsed with clean water.

[0063] The fourth step is drying. The recycled aggregate from the construction solid waste that has been cleaned in the third step is released and dried by baking or air drying to obtain recycled aggregate from construction solid waste reinforced with silicate wastewater.

[0064] Example 7

[0065] This embodiment describes a silicate-containing wastewater-enhanced recycled aggregate for construction solid waste, which involves using silicate-containing wastewater to enhance the recycled aggregate.

[0066] Furthermore, the silicate-containing wastewater is silicate-containing wastewater generated during chemical production, with a pH value of 14, and the silicate content is 18 g / L as SiO2; the recycled aggregate from construction solid waste is recycled stone material formed after waste concrete blocks are crushed, screened, washed, and dried.

[0067] The method for preparing recycled aggregate from construction solid waste reinforced with silicate wastewater in this embodiment includes the following steps:

[0068] The first step is soaking. Silicate-containing wastewater and recycled aggregate from construction solid waste are placed in a closed mixing device, and the silicate-containing wastewater completely submerges the recycled aggregate from construction solid waste by 1-2 cm. The soaking treatment is carried out for 6 hours under normal temperature and pressure.

[0069] The second step is mixing. CO2 gas is introduced into the sealed mixing device after the first soaking treatment. When the pressure reaches 0.8 MPa, the device is mixed at room temperature and pressure for 50 hours. During the mixing treatment, CO2 gas is added every 4 hours to ensure that the pressure in the sealed mixing device is 0.8 MPa. The rotation speed of the sealed mixing device is 32 r / min.

[0070] The third step is cleaning. The silicate-containing wastewater in the closed mixing device after the second step of mixing is discharged, and the recycled aggregate from construction solid waste is rinsed with clean water.

[0071] The fourth step is drying. The recycled aggregate from the construction solid waste that has been cleaned in the third step is released and dried by baking or air drying to obtain recycled aggregate from construction solid waste reinforced with silicate wastewater.

[0072] Example 8

[0073] This embodiment describes a silicate-containing wastewater-enhanced recycled aggregate for construction solid waste, which involves using silicate-containing wastewater to enhance the recycled aggregate.

[0074] Furthermore, the silicate-containing wastewater is silicate-containing wastewater generated during chemical production, with a pH value of 13, and the silicate content is 20 g / L (calculated as SiO2); the recycled aggregate from construction solid waste is recycled stone material formed after waste concrete blocks are crushed, screened, washed, and dried.

[0075] The method for preparing recycled aggregate from construction solid waste reinforced with silicate wastewater in this embodiment includes the following steps:

[0076] The first step is soaking. Silicate-containing wastewater and recycled aggregate from construction solid waste are placed in a closed mixing device, and the silicate-containing wastewater completely submerges the recycled aggregate from construction solid waste by 1-2 cm. The soaking treatment is carried out for 6 hours under normal temperature and pressure.

[0077] The second step is mixing. CO2 gas is introduced into the sealed mixing device after the first soaking treatment. When the pressure reaches 0.8 MPa, the device is mixed at room temperature and pressure for 53 hours. During the mixing treatment, CO2 gas is added every 4 hours to ensure that the pressure in the sealed mixing device is 0.8 MPa. The rotation speed of the sealed mixing device is 28 r / min.

[0078] The third step is cleaning. The silicate-containing wastewater in the closed mixing device after the second step of mixing is discharged, and the recycled aggregate from construction solid waste is rinsed with clean water.

[0079] The fourth step is drying. The recycled aggregate from the construction solid waste that has been cleaned in the third step is released and dried by baking or air drying to obtain recycled aggregate from construction solid waste reinforced with silicate wastewater.

[0080] Example 9

[0081] This embodiment describes a silicate-containing wastewater-enhanced recycled aggregate for construction solid waste, which involves using silicate-containing wastewater to enhance the recycled aggregate.

[0082] Furthermore, the silicate-containing wastewater is silicate-containing wastewater generated during chemical production, with a pH value of 12, and the silicate content is 16 g / L as SiO2; the recycled aggregate from construction solid waste is recycled stone material formed after waste concrete blocks are crushed, screened, washed, and dried.

[0083] The method for preparing recycled aggregate from construction solid waste reinforced with silicate wastewater in this embodiment includes the following steps:

[0084] The first step is soaking. Silicate-containing wastewater and recycled aggregate from construction solid waste are placed in a closed mixing device, and the silicate-containing wastewater completely submerges the recycled aggregate from construction solid waste by 1-2 cm. The soaking treatment is carried out for 6.5 hours under normal temperature and pressure.

[0085] The second step is mixing. CO2 gas is introduced into the sealed mixing device after the first soaking treatment. When the pressure reaches 0.9 MPa, the mixing treatment is carried out at room temperature and pressure for 55 hours. During the mixing treatment, CO2 gas is added every 4 hours to ensure that the pressure in the sealed mixing device is 0.9 MPa. The rotation speed of the sealed mixing device is 33 r / min.

[0086] The third step is cleaning. The silicate-containing wastewater in the closed mixing device after the second step of mixing is discharged, and the recycled aggregate from construction solid waste is rinsed with clean water.

[0087] The fourth step is drying. The recycled aggregate from the construction solid waste that has been cleaned in the third step is released and dried by baking or air drying to obtain recycled aggregate from construction solid waste reinforced with silicate wastewater.

[0088] Example 10

[0089] This embodiment describes a silicate-containing wastewater-enhanced recycled aggregate for construction solid waste, which involves using silicate-containing wastewater to enhance the recycled aggregate.

[0090] Furthermore, the silicate-containing wastewater is silicate-containing wastewater generated during chemical production, with a pH value of 14, and the silicate content is 15 g / L as SiO2; the recycled aggregate from construction solid waste is recycled stone material formed after waste concrete blocks are crushed, screened, washed, and dried.

[0091] The method for preparing recycled aggregate from construction solid waste reinforced with silicate wastewater in this embodiment includes the following steps:

[0092] The first step is soaking. Silicate-containing wastewater and recycled aggregate from construction solid waste are placed in a closed mixing device, and the silicate-containing wastewater completely submerges the recycled aggregate from construction solid waste by 1-2 cm. The soaking treatment is carried out for 7 hours under normal temperature and pressure.

[0093] The second step is mixing. CO2 gas is introduced into the sealed mixing device after the first soaking treatment. When the pressure reaches 1.0 MPa, the mixing treatment is carried out at room temperature and pressure for 60 hours. During the mixing treatment, CO2 gas is added every 4 hours to ensure that the pressure in the sealed mixing device is 1.0 MPa. The rotation speed of the sealed mixing device is 35 r / min.

[0094] The third step is cleaning. The silicate-containing wastewater in the closed mixing device after the second step of mixing is discharged, and the recycled aggregate from construction solid waste is rinsed with clean water.

[0095] The fourth step is drying. The recycled aggregate from the construction solid waste that has been cleaned in the third step is released and dried by baking or air drying to obtain recycled aggregate from construction solid waste reinforced with silicate wastewater.

[0096] Application effects of the examples

[0097] According to the methods specified in the national standard "Construction Pebbles and Crushed Stones" (GB / T 14685-2011), the water absorption rate, crushing index, apparent density and bulk density of natural stone, recycled aggregates from construction solid waste and recycled aggregates from construction solid waste enhanced with silicate wastewater prepared in Examples 1 to 10 were tested. The aggregate properties are shown in the table below.

[0098] Table 1 Comparison of Aggregate Properties

[0099]

[0100] Note: The reduction rate of water absorption and the reduction rate of crushing value refer to the proportion by which the water absorption and crushing value of the recycled aggregate from construction solid waste enhanced with silicate wastewater are reduced compared to the unenhanced "recycled aggregate".

[0101] Apparent density enhancement rate and bulk density enhancement rate refer to the proportion by which the apparent density and bulk density of the recycled aggregate from construction solid waste enhanced with silicate wastewater are increased compared to the unenhanced "recycled aggregate".

Claims

1. A recycled aggregate from construction solid waste enhanced with silicate wastewater, characterized in that, The silicate-containing wastewater-enhanced recycled aggregate from construction solid waste is prepared using the following method: Step 1, soaking: Place silicate-containing wastewater and recycled aggregate from construction solid waste into a closed mixing device, ensuring that the silicate-containing wastewater completely submerges the recycled aggregate from construction solid waste by 1-2 cm, and soak for 4-7 hours under normal temperature and pressure. The second step is carbonization enhancement: CO2 gas is introduced into the sealed mixing device after the first soaking treatment. When the pressure reaches 0.5-1.0 MPa, the device is mixed under normal temperature and pressure for 36-60 hours. During the mixing treatment, CO2 gas is added every 4 hours to ensure that the pressure in the sealed mixing device is 0.5-1.0 MPa and the rotation speed of the sealed mixing device is 25-35 r / min. The third step, cleaning: Discharge the silicate-containing wastewater from the closed mixing device after the carbonization and strengthening treatment in the second step, and rinse the recycled aggregate from construction solid waste with clean water. Step 4, drying: The recycled aggregate from the construction solid waste after the cleaning treatment in step 3 is released and dried by baking or air drying to obtain the recycled aggregate from the construction solid waste reinforced with silicate wastewater. The silicate-containing wastewater is wastewater containing silicates generated during chemical production, with a pH value of 12-14, and the silicate content is 15-20 g / L (calculated as SiO2); the recycled aggregate from construction solid waste is recycled stone material formed after waste concrete blocks are crushed, screened, washed, and dried.

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