A seawater-mixed, high-pressure salt-erosion resistant solid waste seepage-proof grouting material and its preparation method

Abstract

This invention discloses a high-pressure salt-erosion resistant solid waste seepage-proof grouting material mixed with seawater and its preparation method. This high-pressure salt-erosion resistant solid waste seepage-proof grouting material can adapt to high-salt and high-pressure environments. Furthermore, the raw materials used are almost "zero-cost": the solid raw materials are all taken from solid waste, realizing the resource utilization of solid waste; the strongly alkaline leachate from the alkali slag field is used as an alkali activator, treating waste with waste; finally, seawater is used for mixing according to local conditions, which not only saves a large amount of freshwater resources but also improves seepage-proof performance.

Description

Technical Field

[0001] This invention belongs to the technical field of cement slurry composition, specifically relating to a high-pressure salt corrosion resistant solid waste seepage prevention grouting material mixed with seawater and its preparation method. Background Technology

[0002] With the rapid development of underground engineering construction, the problem of seepage prevention and plugging in underground projects has become increasingly prominent. Groundwater is rich in various salt ions, especially chloride and sulfate ions, which have a significant corrosive effect on traditional cement-based grouting materials, leading to a decrease in material strength and insufficient durability. Coastal underground projects often face the dual effects of high water pressure and strong ionic corrosion (with magnesium, chloride, and sulfate ions being typical corrosive ions in groundwater), exacerbating the long-term safety and stability of underground projects. Currently, commonly used cement grouts consume a large amount of resources and generate high carbon emissions, and lack resistance to salt corrosion and high-pressure seepage, making it difficult to meet the long-term seepage prevention requirements under complex geological conditions.

[0003] Essentially, urban bulk solid waste has become a serious challenge to the country's sustainable development, and there is an urgent need to prepare new environmentally friendly grouting materials that combine the characteristics of different solid wastes and the regional solid waste utilization features. Summary of the Invention

[0004] The purpose of this invention is to provide a high-pressure salt corrosion resistant solid waste seepage prevention grouting material mixed with seawater, which can adapt to high-salt and high-pressure environments and realize the resource utilization of solid waste.

[0005] Accordingly, the present invention also provides a method for preparing a high-pressure salt corrosion resistant solid waste seepage prevention grouting material mixed with seawater.

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

[0007] A high-pressure salt corrosion resistant solid waste seepage prevention grouting material mixed with seawater is obtained by mixing solid waste main material with seawater;

[0008] The main solid waste material consists of 30-50 wt% activated lead-zinc tailings slag, 30-48 wt% alkaline slag and 2-40 wt% fly ash;

[0009] Lead-zinc tailings slag is calcined at high temperature, cooled to room temperature, and ball-milled to a particle size of less than 20 μm, then activated to obtain activated lead-zinc tailings slag. The high-temperature calcination temperature is 500–1000℃, the calcination time is 3–6 hours, the ball milling speed is 120–200 r / min, and the alkaline activator used is alkaline slag leachate. Preferably, the high-temperature calcination temperature is 800℃, and the time is 4 hours.

[0010] In some preferred embodiments, the activation process involves mixing lead-zinc tailings slag with an alkaline activator at a mass ratio of 5:1 and reacting the mixture at 24-34°C for 1-5 hours. Preferably, the activation temperature is 30°C.

[0011] In some preferred embodiments, the mass ratio of seawater to solid waste is 2:5.

[0012] In some preferred embodiments, the lead-zinc tailings slag has a particle size of less than 20 μm and a moisture content of less than 5 wt%.

[0013] In some preferred embodiments, the particle size of the alkali residue is less than 75 μm and the calcium oxide content is higher than 80 wt%.

[0014] In some preferred embodiments, the pH value of the alkaline residue leachate is 12-14.

[0015] In some preferred embodiments, the fly ash has a particle size of less than 75 μm and a moisture content of less than 2 wt%.

[0016] A method for preparing a high-pressure salt-erosion resistant solid waste seepage-proof grouting material mixed with seawater includes the following steps:

[0017] (1) Lead-zinc tailings slag is calcined at high temperature, cooled to room temperature and then ball-milled to a particle size of less than 20 μm for later use; wherein, the high temperature calcination temperature is 800℃, the high temperature calcination time is 4h, and the ball milling speed is 120~200r / min;

[0018] The alkali residue was dried and ground, and then sieved through a 75μm sieve for later use.

[0019] The fly ash is dried and ground, then sieved through a 75μm sieve for later use.

[0020] (2) The lead-zinc tailings slag treated in step (1) is mixed with an alkaline activator at a mass ratio of 5:1 and reacted at 30°C for 1 to 5 hours to obtain activated lead-zinc tailings slag.

[0021] (3) Mix the activated lead-zinc tailings slag, alkali slag and fly ash in a mass ratio of 30~50:30~48:2~40 to obtain the main solid waste material;

[0022] (4) When using, seawater and solid waste main materials are mixed to obtain high pressure salt corrosion resistant solid waste anti-seepage grouting material.

[0023] In some preferred embodiments, the mass ratio of seawater to solid waste is 2:5.

[0024] The present invention has at least the following beneficial effects:

[0025] (1) The high-pressure salt corrosion resistant solid waste anti-seepage grouting material prepared by the present invention has good anti-seepage performance and still performs well in high-pressure salt corrosion environment.

[0026] (2) The raw materials used in this invention are almost "zero cost": the solid raw materials are all taken from solid waste, realizing the resource utilization of solid waste; the strong alkaline leachate from the alkali slag field is used as an alkali activator to treat waste with waste; finally, seawater is used for mixing according to local conditions, which not only saves a lot of fresh water resources, but also improves the seepage prevention performance.

[0027] (3) The preparation method used in this invention is simple and easy to scale up production. Detailed Implementation

[0028] The technical solution of the present invention will be further explained and described below through specific embodiments.

[0029] In the following embodiments, unless otherwise specified, the water used may be one or more of distilled water, purified water, and drinking water; the performance indicators of fly ash not otherwise specified may refer to GB / T 1596-2017; the detection methods in the following embodiments are all conventional detection methods unless otherwise specified; the reagents in the following embodiments are all purchased from commercial channels unless otherwise specified.

[0030] I. Preparation of High-Pressure Salt Corrosion Resistant Solid Waste Seepage Prevention Grouting Material

[0031] The preparation method includes the following steps:

[0032] (1) Lead-zinc tailings slag is calcined at high temperature, cooled to room temperature and then ball-milled to a particle size of less than 20 μm for later use;

[0033] The high-temperature calcination temperature is 800℃, the high-temperature calcination time is 4h, and the ball mill speed is 120~200r / min; the water content of the lead-zinc tailings slag after the above treatment is less than 5wt%.

[0034] (2) Dry and grind the alkali residue, and sieve it through a sieve with a pore size of 75μm for later use. The calcium oxide content of the alkali residue is higher than 80wt%.

[0035] (3) Dry the fly ash to a moisture content of less than 2wt%, then grind it, and finally sieve it through a sieve with a pore size of 75μm for later use.

[0036] (4) The lead-zinc tailings slag treated in step (1) is mixed with an alkaline activator at a mass ratio of 5:1 and reacted at 30°C for a period of time (activation time) to obtain activated lead-zinc tailings slag.

[0037] (5) The activated lead-zinc tailings slag, alkali slag and fly ash are mixed in a J16 cement mixer for 300s to obtain solid waste main material.

[0038] (6) Mix seawater and solid waste main material in a cylindrical mold of 80*100mm at a mass ratio of 2:5. Then, after curing at room temperature of 20 ± 2℃ and relative humidity of ≥ 50% for 24 hours, demold and continue curing for 7 days to obtain test samples corresponding to each embodiment.

[0039] The feed ratio and activation time for each embodiment are shown in Table 1:

[0040] Table 1. Preparation parameters for Examples 1-7

[0041]

[0042] II. Performance Testing

[0043] (1) Test of seepage prevention performance under no-pressure conditions

[0044] The tests were conducted in accordance with the Geotechnical Testing Procedure GB50123-2019, and the results are shown in Table 2.

[0045] Table 2. Permeability coefficients of Examples 1-7 under pressureless conditions.

[0046] Test sample Permeability coefficient m / s Example 1 <![CDATA[2.37×10 -9 ]]> Example 2 <![CDATA[8.49×10 -10 ]]> Example 3 <![CDATA[6.24×10 -10 ]]> Example 4 <![CDATA[6.07×10 -10 ]]> Example 5 <![CDATA[4.47×10 -10 ]]> Example 6 <![CDATA[8.64×10 -10 ]]> Example 7 <![CDATA[7.82×10 -10 ]]>

[0047] As can be seen from Examples 1-4, within a certain time range, the seepage prevention performance of the high-pressure salt corrosion resistant solid waste seepage prevention grouting material is positively correlated with the activation time of lead-zinc tailings slag. When the activation time is 1 hour, its permeability coefficient is 2.37 × 10⁻⁶. -9 The permeability was m / s, but after 2 hours of activation, its permeability decreased by an order of magnitude to 8.49 × 10⁻⁶ m / s. -10 m / s; in contrast, its permeability coefficient did not change much after 3h and 4h of excitation, remaining at 6.24×10 m / s. -10 m / s and 6.07×10 -10 m / s. Overall, the seepage prevention performance of the slurry after solidification is excellent and increases with the increase of tailings activation time.

[0048] Comparing Examples 3, 5, and 6, it can be seen that the higher the lead-zinc tailings content, the greater the permeability coefficient. When the tailings content is between 30% and 50%, the permeability coefficient remains stable at 4 to 9 × 10⁻⁶. -10 Within the m / s range, it exhibits excellent seepage prevention performance. A comparison of Examples 3 and 7 shows that the lower the alkali residue content, the higher the permeability coefficient; good seepage prevention effects can be achieved with alkali residue content between 30% and 48%.

[0049] (2) Test on the seepage prevention performance of traditional cement grout and high-pressure salt corrosion resistant solid waste seepage prevention grouting material under high pressure-salt corrosion.

[0050] Testing instruments: The test was conducted using a high water pressure plate and a rigid wall permeameter. The high water pressure plate was a GEOTACM10000 standard water pressure plate.

[0051] Test environment: The concentrations of chloride ions (19.4 mg / L), sulfate ions (2.77 mg / L), and magnesium ions (1.31 mg / L) were calculated according to the various ionic solutions required for simulating seawater preparation in the standard ASTM D1148-98. Based on this, the corrosion conditions of complex ions in the actual environment were simulated.

[0052] Test samples: The preparation methods of Examples 3 and 5-7 are as described above, and the ordinary Portland cement is PO42.5R type cement. Specific test conditions and test results are shown in Table 3.

[0053] Table 3. Test conditions and results of permeability coefficient under high pressure-salt corrosion conditions.

[0054] Test sample water pressure Dissolution environment Permeability coefficient m / s Example 3 0 water <![CDATA[6.24×10 -10 ]]> Example 3 0.25MPa water <![CDATA[6.37×10 -10 ]]> Example 3 0.50MPa water <![CDATA[6.94×10 -10 ]]> Example 3 0.75MPa water <![CDATA[7.23×10 -10 ]]> Example 3 0.75MPa chloride ions <![CDATA[7.62×10 -10 ]]> Example 5 0.75MPa chloride ions <![CDATA[6.88×10 -10 ]]> Example 6 0.75MPa chloride ions <![CDATA[8.04×10 -10 ]]> Example 7 0.75MPa chloride ions <![CDATA[7.85×10 -10 ]]> Example 3 0.75MPa sulfate <![CDATA[7.29×10 -10 ]]> Example 5 0.75MPa sulfate <![CDATA[6.74×10 -10 ]]> Example 6 0.75MPa sulfate <![CDATA[7.83×10 -10 ]]> Example 7 0.75MPa sulfate <![CDATA[7.41×10 -10 ]]> Example 3 0.75MPa magnesium ions <![CDATA[8.46×10 -10 ]]> Example 5 0.75MPa magnesium ions <![CDATA[8.04×10 -10 ]]> Example 6 0.75MPa magnesium ions <![CDATA[9.23×10 -10 ]]> Example 7 0.75MPa magnesium ions <![CDATA[8.64×10 -10 ]]> Ordinary Portland cement 0.75MPa water <![CDATA[9.22×10 -10 ]]> Ordinary Portland cement 0.75MPa chloride ions <![CDATA[2.18×10 -9 ]]> Ordinary Portland cement 0.75MPa sulfate <![CDATA[4.43×10 -9 ]]> Ordinary Portland cement 0.75MPa magnesium ions <![CDATA[9.46×10 -9 ]]>

[0055] According to the table above, the permeability coefficient of the high-pressure salt corrosion resistant solid waste seepage prevention grouting material in water is 6.24~7.23×10⁻⁶ under pressures of 0~0.75MPa. -10 The m / s indicates that the high-pressure underwater material has excellent seepage prevention effect, and its permeability coefficient in water under the same pressure is 7.23×10 m / s. -10 The permeability coefficient (m / s) is lower than that of ordinary Portland cement (9.22×10⁻⁶ m / s). -10 m / s).

[0056] Under high pressure (0.75 MPa water pressure) coupled with chloride ions, the permeability coefficient of the high-pressure salt corrosion resistant solid waste seepage prevention grouting material is relatively low, fluctuating between 6.88 and 8.04 × 10⁻⁶. -10 Within the m / s range, its permeability coefficient is far lower than that of ordinary silicate cement at the same chloride ion corrosion concentration (2.18×10). -9 m / s).

[0057] Under high pressure (0.75 MPa water pressure) coupled with sulfate ions, the permeability coefficient of the high-pressure salt corrosion resistant solid waste seepage prevention grouting material is relatively low, fluctuating between 6.74 and 7.83 × 10⁻⁶. -10 Within the m / s range, its permeability coefficient is far lower than that of ordinary silicate cement at the same sulfate ion corrosion concentration (4.43×10). -9 m / s).

[0058] Under high pressure (0.75 MPa water pressure) coupled with magnesium ion concentration, the permeability coefficient of the high-pressure salt corrosion resistant solid waste seepage prevention grouting material increased slightly, fluctuating between 8.04 and 9.23 × 10⁻⁶.-10 Within the range of m / s, but still far lower than the permeability coefficient of ordinary Portland cement at the same magnesium ion corrosion concentration (9.46×10). -9 m / s).

[0059] The above experiments demonstrate that the high-pressure salt-corrosion resistant solid waste anti-seepage grouting material provided by this invention has a low permeability coefficient under high-pressure-salt-corrosion conditions, and its anti-seepage performance is superior to that of traditional ordinary silicate cement.

[0060] The above description is merely a preferred embodiment of the present invention, and therefore should not be construed as limiting the scope of the present invention. All equivalent changes and modifications made in accordance with the scope of the patent and the contents of the specification should still fall within the scope of the present invention.

Claims

1. A seawater mixed high-pressure salt corrosion resistant full solid waste anti-seepage grouting material, characterized in that, The solid waste main material is mixed with seawater to obtain the full-solid waste anti-seepage grouting material; The solid waste main material is composed of 30-50wt% of activated lead-zinc tailings, 30-48wt% of alkali residue and 2-40wt% of fly ash; The lead-zinc tailings are calcined at high temperature, cooled to room temperature, ball-milled to a particle size of less than 20μm, and then activated to obtain the activated lead-zinc tailings; wherein the temperature of high-temperature calcination is 500-1000℃, the time of high-temperature calcination is 3-6h, the rotation speed of ball-milling is 120-200r / min, and the alkali activator used for activation is alkali residue leachate; The operation of activation is that the lead-zinc tailings and the alkali activator are mixed at a mass ratio of 5:1, and then reacted at 24-34℃ for 1-5h to obtain the activated lead-zinc tailings; The alkali residue leachate is collected from an alkali residue field.

2. The high-pressure salt corrosion resistant full-solid waste anti-seepage grouting material according to claim 1, characterized in that, The mass ratio of the seawater to the solid waste main material is 2:

5. 3.The high-pressure salt corrosion resistant full-solid waste anti-seepage grouting material of claim 1, wherein, The particle size of the lead-zinc tailings is less than 20μm, and the water content is less than 5wt%. 4.The high-pressure salt corrosion resistant full-solid waste anti-seepage grouting material of claim 1, wherein, The particle size of the alkali residue is less than 75μm, and the calcium oxide content is higher than 80wt%. 5.The high-pressure salt corrosion resistant full-solid waste anti-seepage grouting material of claim 1, wherein, The particle size of the fly ash is less than 75μm, and the water content is less than 2wt%.

6. The method for preparing the seawater-mixed high-pressure salt corrosion resistant full solid waste anti-seepage grouting material according to any one of claims 1-5, characterized in that, The method comprises the following steps: (1) The lead-zinc tailings are sequentially subjected to high-temperature calcination, cooling to room temperature, and then ball-milling to a particle size of less than 20μm for standby; wherein the temperature of high-temperature calcination is 800℃, the time of high-temperature calcination is 4h, and the rotation speed of ball-milling is 120-200r / min; The alkali residue is dried and ground, and then sieved with a screen mesh having a pore size of 75μm for standby; The fly ash is dried and ground, and then sieved with a screen mesh having a pore size of 75μm for standby; (2) The lead-zinc tailings treated in step (1) and the alkali activator are mixed at a mass ratio of 5:1, and then reacted at 30℃ for 1-5h to obtain the activated lead-zinc tailings; (3) The activated lead-zinc tailings, the alkali residue and the fly ash are mixed at a mass ratio of 30-50:30-48:2-40 to obtain the solid waste main material; The seawater and the solid waste main material are mixed to obtain the full-solid waste anti-seepage grouting material.

7. The production method according to claim 6, wherein The mass ratio of the seawater to the solid waste main material is 2:5.

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