A siltstone slag is used as a shield foam wall back grouting material and a preparation method thereof

Abstract

The application relates to a kind of shield foam wall post-grouting material using siltstone slag and a preparation method, and belongs to the technical field of shield tunnel construction.The shield foam wall post-grouting material using siltstone slag comprises slurry and water glass, and the slurry comprises cement 5-10% by mass fraction, fly ash 13-18%, sodium dihydrogen phosphate 0.1-0.6%, bentonite 4-8%, bubble liquid 0.5-2%, pretreated siltstone 34-39%, xanthan gum 1-5%, and the rest is water, and the volume ratio of the slurry to water glass is 1:0.1-0.14.The application replaces river sand with siltstone, solves the problem of difficult disposal of waste slag, is an economic and environmentally-friendly method for recycling waste soil, and has good environmental benefits.

Description

Technical Field

[0001] This invention belongs to the field of shield tunnel construction technology, specifically relating to a grouting material for shield foam wall using siltstone slag and its preparation method. Background Technology

[0002] Shield tunneling is a construction method that uses a tunnel boring machine (TBM) to excavate tunnels underground. Its application in major underground engineering projects in my country is becoming increasingly widespread, and it has become a primary method for tunnel construction. Simultaneous grouting is a construction method that injects grout into the gap between the shield tail through pre-reserved grouting holes. Simultaneous grouting technology can promptly fill the annular gap between the tunnel segments and the ground, and can effectively control ground deformation and stabilize the tunnel segment structure. Currently, the aggregate for simultaneous grouting in shield tunneling is mainly river sand. However, river sand resources are becoming increasingly scarce, and over-exploitation of river sand will lead to ecological damage and resource depletion. Therefore, finding green and economical alternative aggregates has become an urgent need for the industry.

[0003] The tunneling process of tunnel boring machines inevitably generates a large amount of excavated soil, and most projects face the problem of large-scale excavated soil disposal. For example, the invention patent with application publication number CN121322034A discloses a method for preparing thick mud to prevent grout loss using siltstone excavated soil from tunnel boring machines. This method uses bentonite slurry as the base slurry, and then adds waste weathered rock powder, calcium carbonate, sodium carbonate, xanthan gum or positively charged gel to make a plastic flowable slurry, realizing the rational resource utilization of excavated soil. However, siltstone is prone to disintegration when exposed to water and its strength decreases rapidly. The shield synchronous grouting slurry prepared by directly using siltstone instead of river sand will be diluted and dispersed in water-rich strata, posing a risk of insufficient strength in the later stages. Summary of the Invention

[0004] The first objective of this invention is to provide a grouting material for the foam wall of a shield tunnel, which solves the technical problem of low grout strength caused by the softening of siltstone when it comes into contact with water when siltstone is used as aggregate instead of river sand.

[0005] The second objective of this invention is to provide a method for preparing grouting material for shield tunnel foam walls using siltstone slag.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A grouting material for shield tunneling foam walls using siltstone slag includes a grout and water glass. The grout, by mass percentage, comprises 5-10% cement, 13-18% fly ash, 0.1-0.6% sodium dihydrogen phosphate, 4-8% bentonite, 0.5-2% aerated liquid, 34-39% pretreated siltstone, 1-5% xanthan gum, and the remainder water. The volume ratio of the grout to water glass is 1:0.1-0.14.

[0007] Furthermore, the preparation method of the pretreated siltstone includes: immersing the siltstone in an aminosilane coupling agent solution, adjusting the pH to 4.5-5.5, reacting at 40-60 ℃ for 1-2 h, then centrifuging and drying to obtain siltstone with amino groups on the surface, immersing the siltstone with amino groups on the surface in a metal ion solution, and vacuum drying to obtain the final product.

[0008] Furthermore, the aminosilane coupling agent in the aminosilane coupling agent solution has a mass fraction of 2-10 wt%, and the aminosilane coupling agent in the aminosilane coupling agent solution is KH792.

[0009] Furthermore, the metal ion solution is one or more of calcium ion solution, magnesium ion solution, and ferrous ion solution; the concentration of metal ions in the metal ion solution is 0.05–0.1 mol / L.

[0010] Furthermore, the siltstone containing amino groups on its surface is immersed in a metal ion solution for 20–30 min; the heating procedure for obtaining the pretreated siltstone by vacuum drying is as follows: drying at 25–40 °C for 1–2 h, followed by drying at 40–90 °C for 2–3 h, and finally drying at 90–110 °C for 1–2 h.

[0011] Furthermore, the siltstone includes siltstone with a particle size of 0.5 to 2 mm and siltstone with a particle size of 0.1 to 0.25 mm, and the mass ratio of siltstone with a particle size of 0.5 to 2 mm to siltstone with a particle size of 0.1 to 0.25 mm is 1:1 to 3:2.

[0012] Furthermore, the bubble liquid is composed of a mixed foaming agent and water, wherein the mass ratio of the mixed foaming agent to water is 1:10 to 1:20; the mixed foaming agent is a first foaming agent and a second foaming agent mixed in a mass ratio of 1:1, wherein the first foaming agent is one or more of sodium dodecylbenzenesulfonate, sodium dodecyl sulfate, and sodium carbonate, and the second foaming agent is dodecyl dimethylamine oxide.

[0013] Furthermore, the cement is PO 42.5 cement, the fly ash is grade I or grade II fly ash, the bentonite is calcium-based bentonite, and the water glass has a Baume degree of 30–40 °Bé.

[0014] A method for preparing a grouting material for shield tunnel foam walls using siltstone slag includes the following steps: mixing the cement, fly ash, sodium dihydrogen phosphate, bentonite, air-filled liquid, pretreated siltstone, xanthan gum and water according to the formula to obtain grout one; before the shield machine excavates, adding the water glass according to the formula and stirring at a speed of 80-160 r / min for 3-5 min to obtain the final grout.

[0015] The beneficial effects of this invention are: This invention introduces air bubbles into the grouting material after using siltstone slag as the foam wall of a tunnel boring machine (TBM). These air bubbles act as ball bearings, increasing the fluidity of the grouting material and reducing its density, thus preventing the tunnel segments from floating. This invention replaces river sand with siltstone, solving the problem of difficult disposal of waste soil. It is an economical and environmentally friendly method for waste soil reuse, offering significant environmental benefits.

[0016] Water glass contains negatively charged silica colloidal particles. These particles combine with metal ions on the surface of pretreated siltstone, promoting cross-linking and hardening. This binds the loose pretreated siltstone into a solid network, increasing the erosion resistance of the grouting material used as shield foam wall in water-rich formations. The hydroxyl groups on xanthan gum molecules can also combine with metal ions on the surface of pretreated siltstone. This multiple bonding mechanism further enhances the strength and durability of the grouting material used as shield foam wall.

[0017] The silanol groups generated by the hydrolysis of the methoxy groups in aminosilane coupling agent KH792 condense with the silanol groups on the surface of siltstone, forming a hydrophobic layer on the siltstone surface. This effectively avoids the problem of siltstone softening and reducing strength when exposed to water, thus increasing the water resistance of the siltstone. At the same time, the amino complex metal ions on the silane coupling agent KH792 enrich the surface of the siltstone with active metal ions. Detailed Implementation

[0018] The present invention will be further described below with reference to embodiments thereof.

[0019] Example 1 Example 1 uses siltstone slag as the grouting material for the shield tunnel foam wall, which includes grout and water glass. The grout consists of the following raw materials: 5 kg of PO 42.5 cement, 15 kg of Grade I fly ash, 0.6 kg of sodium dihydrogen phosphate, 8 kg of calcium-based bentonite, 1 kg of aerated liquid, 34 kg of pretreated siltstone, 1 kg of xanthan gum, and 35.4 kg of water. Water glass accounts for 10% of the grout volume. The water glass has a Baume degree of 30°Bé.

[0020] The preparation method of pretreated siltstone includes: screening the waste soil discharged from shield tunneling in siltstone strata using a vibrating screen to separate siltstone with a particle size of 0.5–2 mm and siltstone with a particle size of 0.1–0.25 mm, with a mass ratio of 0.5–2 mm to 0.1–0.25 mm of siltstone at 1:1. The two particle sizes of siltstone are mixed, and the mixed siltstone is then immersed in an aminosilane coupling agent KH792 solution, the pH is adjusted to 5, and the reaction is carried out at 40 °C for 2 h. After centrifugation and drying, siltstone with amino groups on its surface is obtained. This amino-containing siltstone is then immersed in a calcium ion solution with a calcium ion concentration of 0.05 mol / L for 20 min, followed by separation and vacuum drying to obtain the pretreated siltstone. The aminosilane coupling agent KH792 solution was an ethanolic solution of aminosilane coupling agent KH792, with a mass fraction of 6 wt%. The vacuum drying procedure was as follows: drying at 25 °C for 1 h, followed by drying at 60 °C for 2 h, and finally drying at 100 °C for 1 h. Calcium ions were provided by calcium chloride.

[0021] The preparation method of the bubble solution is as follows: 0.2 kg of sodium dodecylbenzenesulfonate, 0.2 kg of dodecyl dimethylamine oxide and 4 kg of water are mixed to obtain the solution.

[0022] The preparation method of the post-grouting material for shield tunnel foam wall using siltstone slag in Example 1 includes: mixing the formula amount of PO 42.5 cement, grade I fly ash, sodium dihydrogen phosphate, calcium-based bentonite, air bubble liquid, pretreated siltstone, xanthan gum and water to obtain grout one; before the shield machine tunnels, add the formula amount of water glass and stir at 80 r / min for 3 minutes to obtain the final grout.

[0023] Example 2 Example 2 uses siltstone slag as the grouting material for the shield tunnel foam wall, comprising grout and water glass. The grout consists of the following raw materials: 10 kg of PO 42.5 cement, 13 kg of Grade I fly ash, 0.1 kg of sodium dihydrogen phosphate, 5 kg of calcium-based bentonite, 2 kg of aerated liquid, 39 kg of pretreated siltstone, 2 kg of xanthan gum, and 28.9 kg of water. Water glass accounts for 10% of the grout volume. The water glass has a Baume degree of 30°Bé.

[0024] The preparation method of pretreated siltstone includes: screening the waste soil discharged from shield tunneling in siltstone strata using a vibrating screen to separate siltstone with a particle size of 0.5–2 mm and siltstone with a particle size of 0.1–0.25 mm, with a mass ratio of 3:2 between the two particle sizes. The two types of siltstone are then mixed and immersed in an aminosilane coupling agent KH792 solution, adjusting the pH to 4.5 and reacting at 50 °C for 2 h. After centrifugation and drying, siltstone with amino groups on its surface is obtained. This amino-containing siltstone is then immersed in a calcium ion solution with a calcium ion concentration of 0.1 mol / L for 20 min, followed by centrifugation and vacuum drying to obtain the pretreated siltstone. The aminosilane coupling agent KH792 solution is an ethanolic solution of aminosilane coupling agent KH792, with a mass fraction of 10 wt%. The vacuum drying procedure is as follows: drying at 30 °C for 1 h, followed by drying at 90 °C for 3 h, and finally drying at 100 °C for 2 h. Calcium ions are provided by calcium chloride.

[0025] The preparation method of the bubble solution is as follows: 0.2 kg of sodium dodecylbenzenesulfonate, 0.2 kg of dodecyl dimethylamine oxide and 6 kg of water are mixed to obtain the solution.

[0026] The preparation method of the post-grouting material for shield tunnel foam wall using siltstone slag in Example 2 includes: mixing PO 42.5 cement, grade I fly ash, sodium dihydrogen phosphate, calcium-based bentonite, air-filled liquid, pretreated siltstone, xanthan gum and water to obtain grout one; before the shield machine excavates, adding water glass according to the formula and stirring at 100 r / min for 3 minutes to obtain the final grout.

[0027] Example 3 Example 3 uses siltstone slag as the grouting material for the shield tunnel foam wall, comprising grout and water glass. The grout consists of the following raw materials: 8 kg of PO 42.5 cement, 16 kg of Grade I fly ash, 0.5 kg of sodium dihydrogen phosphate, 4 kg of calcium-based bentonite, 1 kg of aeration liquid, 35 kg of pretreated siltstone, 3 kg of xanthan gum, and 32.5 kg of water. Water glass accounts for 13% of the grout volume. The water glass has a Baume degree of 40°Bé.

[0028] The preparation method of pretreated siltstone includes: screening the waste soil discharged from shield tunneling in siltstone strata using a vibrating screen to separate siltstone with a particle size of 0.5–2 mm and siltstone with a particle size of 0.1–0.25 mm, with a mass ratio of 0.5–2 mm to 0.1–0.25 mm of siltstone at 1:1. The two particle sizes of siltstone are mixed, and the mixed siltstone is then immersed in an aminosilane coupling agent KH792 solution, the pH is adjusted to 5.5, and the reaction is carried out at 60 ℃ for 1 h. After centrifugation and drying, siltstone with amino groups on its surface is obtained. This amino-containing siltstone is then immersed in a magnesium ion solution with a magnesium ion concentration of 0.05 mol / L for 20 min, followed by centrifugation and vacuum drying to obtain the pretreated siltstone. The aminosilane coupling agent KH792 solution is an ethanolic solution of aminosilane coupling agent KH792, with a mass fraction of 3 wt%. The vacuum drying procedure is as follows: drying at 40 °C for 1 h, followed by drying at 70 °C for 2 h, and finally drying at 110 °C for 2 h. Magnesium ions are provided by magnesium chloride.

[0029] The preparation method of the bubble solution is as follows: 0.2 kg of sodium dodecylbenzenesulfonate, 0.2 kg of dodecyl dimethylamine oxide and 8 kg of water are mixed to obtain the solution.

[0030] The preparation method of the post-grouting material for shield tunnel foam wall using siltstone slag in Example 3 includes: mixing the formula amount of PO 42.5 cement, grade I fly ash, sodium dihydrogen phosphate, calcium-based bentonite, air bubble liquid, pretreated siltstone, xanthan gum and water to obtain grout one; before the shield machine tunnels, add the formula amount of water glass and stir at 80 r / min for 5 minutes to obtain the final grout.

[0031] Example 4 Example 4 uses siltstone slag as the grouting material for the shield tunnel foam wall, comprising grout and water glass. The grout consists of the following raw materials: 6 kg of PO 42.5 cement, 18 kg of Grade I fly ash, 0.6 kg of sodium dihydrogen phosphate, 6 kg of calcium-based bentonite, 0.5 kg of aeration fluid, 36 kg of pretreated siltstone, 5 kg of xanthan gum, and 27.9 kg of water. Water glass accounts for 14% of the grout volume. The water glass has a Baume degree of 40°Bé.

[0032] The preparation method of pretreated siltstone includes: screening the waste soil discharged from shield tunneling in siltstone strata using a vibrating screen to separate siltstone with a particle size of 0.5–2 mm and siltstone with a particle size of 0.1–0.25 mm, with a mass ratio of 0.5–2 mm to 0.1–0.25 mm of siltstone at 1:1. The two particle sizes of siltstone are mixed, and the mixed siltstone is then immersed in an aminosilane coupling agent KH792 solution, the pH is adjusted to 5, and the reaction is carried out at 60 °C for 2 h. After centrifugation and drying, siltstone with amino groups on its surface is obtained. This amino-containing siltstone is then immersed in a ferrous ion solution with a concentration of 0.05 mol / L for 20 min, followed by centrifugation and vacuum drying to obtain the pretreated siltstone. The aminosilane coupling agent KH792 solution is an ethanolic solution of aminosilane coupling agent KH792, with a mass fraction of 2 wt%. The vacuum drying procedure is as follows: drying at 40 °C for 2 h, followed by drying at 80 °C for 3 h, and finally drying at 90 °C for 2 h. Ferrous ions are provided by ferrous chloride.

[0033] The preparation method of the bubble solution is as follows: 0.2 kg of sodium dodecylbenzenesulfonate, 0.2 kg of dodecyl dimethylamine oxide and 4 kg of water are mixed to obtain the solution.

[0034] The preparation method of the post-grouting material for shield tunnel foam wall using siltstone slag in Example 4 includes: mixing PO 42.5 cement, grade I fly ash, sodium dihydrogen phosphate, calcium-based bentonite, air-filled liquid, pretreated siltstone, xanthan gum and water to obtain grout one; before the shield machine tunnels, adding water glass according to the formula and stirring at 160 r / min for 3 minutes to obtain the final grout.

[0035] Comparative Example 1 Comparative Example 1 uses siltstone slag as the grouting material for the shield tunnel foam wall, which includes grout and water glass. The grout consists of the following raw materials: 5 kg of PO 42.5 cement, 15 kg of Grade I fly ash, 0.6 kg of sodium dihydrogen phosphate, 8 kg of calcium-based bentonite, 1 kg of aerated liquid, 34 kg of siltstone, 1 kg of xanthan gum, and 39.4 kg of water. Water glass accounts for 10% of the grout volume. The water glass has a Baume degree of 30°Bé.

[0036] Comparative Example 1 uses siltstone instead of pretreated siltstone. The preparation methods for the bubble liquid and the grouting material using siltstone slag as the shield foam wall in Comparative Example 1 are the same as those in Example 1.

[0037] Comparative Example 2 Comparative Example 2 used siltstone slag as the grouting material for the shield tunnel foam wall, which included grout and water glass. The grout consisted of the following raw materials: 5 kg of PO 42.5 cement, 15 kg of Grade I fly ash, 0.6 kg of sodium dihydrogen phosphate, 8 kg of calcium-based bentonite, 1 kg of aeration liquid, 34 kg of pretreated siltstone, and 39.4 kg of water. Water glass accounted for 10% of the grout volume. The water glass had a Baume degree of 30°Bé. Xanthan gum was not added in Comparative Example 2.

[0038] The preparation methods of the bubble liquid, pretreated siltstone, and grouting material for shield foam walls in Comparative Example 2 are the same as those in Example 1.

[0039] Comparative Example 3 Comparative Example 3 uses siltstone slag as the grouting material for the shield tunnel foam wall, which includes grout and water glass. The grout consists of the following raw materials: 5 kg of PO 42.5 cement, 15 kg of Grade I fly ash, 0.6 kg of sodium dihydrogen phosphate, 8 kg of calcium-based bentonite, 1 kg of aerated liquid, 34 kg of siltstone, and 39.4 kg of water. Water glass accounts for 10% of the grout volume. The water glass has a Baume degree of 30°Bé.

[0040] Comparative Example 3 used siltstone instead of pretreated siltstone and did not add xanthan gum.

[0041] The preparation methods of the bubble liquid in Comparative Example 3 and the grouting material for the shield foam wall using siltstone slag are the same as those in Example 1.

[0042] Comparative Example 4 Comparative Example 4 uses siltstone slag as the grouting material for the shield tunnel foam wall, which includes grout and water glass. The grout consists of the following raw materials: 5 kg of PO 42.5 cement, 15 kg of Grade I fly ash, 0 kg of sodium dihydrogen phosphate, 8 kg of calcium-based bentonite, 1 kg of aeration liquid, 34 kg of pretreated siltstone, 1 kg of xanthan gum, and 36 kg of water. Water glass accounts for 5% of the grout volume. The water glass has a Baume degree of 30°Bé.

[0043] The preparation methods of the pretreated siltstone, bubble liquid, and grouting material for shield foam walls in Comparative Example 4 are the same as those in Example 1.

[0044] Comparative Example 5 Comparative Example 5 uses siltstone slag as the grouting material for the shield tunnel foam wall, which includes grout and water glass. The grout consists of the following raw materials: 5 kg of PO 42.5 cement, 15 kg of Grade I fly ash, 0 kg of sodium dihydrogen phosphate, 8 kg of calcium-based bentonite, 0 kg of aerated liquid, 34 kg of pretreated siltstone, 1 kg of xanthan gum, and 37 kg of water. Water glass accounts for 20% of the grout volume. The water glass has a Baume degree of 30°Bé.

[0045] The preparation methods for the pretreated siltstone of Comparative Example 5 and the grouting material for shield foam walls made from siltstone slag are the same as those for Example 1.

[0046] The performance of the grouting material used as the foam wall of the shield tunnel in Examples 1-4 and Comparative Examples 1-5 was tested, and the results are shown in Table 1.

[0047] Table 1. Performance test results of grouting materials used as shield tunnel foam walls in Examples 1-4 and Comparative Examples 1-5. As shown in Table 1, the grouting material for shield tunnel foam walls using siltstone slag of the present invention has good fluidity, early strength, and low density, which can prevent the segments from floating. In Comparative Example 1, siltstone was used instead of pretreated siltstone. The siltstone softens when exposed to water, which reduces the strength of the grouting material for shield tunnel foam walls in Comparative Example 1. Comparative Example 2 did not add xanthan gum, and therefore did not form a network structure with multiple mechanisms. Consequently, the early strength and 28-day compressive strength of the grout were reduced, resulting in poor durability.

[0048] Other embodiments of this disclosure will readily occur to those skilled in the art upon consideration of the specification and practical disclosure. This disclosure is intended to cover any variations, uses, or adaptations of this disclosure that follow the general principles of this disclosure and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of this disclosure are indicated by the claims.

[0049] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. The scope of patent protection of the present invention shall be determined by the claims. Similarly, any equivalent structural changes made based on the content of the present invention's specification shall also be included within the scope of protection of the present invention.

Claims

1. A grouting material for the foam wall of a tunnel boring machine using siltstone slag, characterized in that, The mixture comprises a slurry and water glass. The slurry, by mass percentage, comprises 5-10% cement, 13-18% fly ash, 0.1-0.6% sodium dihydrogen phosphate, 4-8% bentonite, 0.5-2% aerated liquid, 34-39% pretreated siltstone, 1-5% xanthan gum, and the remainder water. The volume ratio of the slurry to water glass is 1:0.1-0.

14.

2. The grouting material for shield tunnel foam walls using siltstone slag as described in claim 1, characterized in that, The method for preparing the pretreated siltstone includes: immersing the siltstone in an aminosilane coupling agent solution, adjusting the pH to 4.5-5.5, reacting at 40-60 ℃ for 1-2 h, then centrifuging and drying to obtain siltstone with amino groups on the surface, immersing the siltstone with amino groups on the surface in a metal ion solution, and then vacuum drying to obtain the final product.

3. The grouting material for shield tunnel foam walls using siltstone slag as described in claim 2, characterized in that, The aminosilane coupling agent in the solution has a mass fraction of 2-10 wt%, and the aminosilane coupling agent in the solution is KH792.

4. The grouting material for shield tunnel foam walls using siltstone slag as described in claim 2, characterized in that, The metal ion solution is one or more of calcium ion solution, magnesium ion solution, and ferrous ion solution; the concentration of metal ions in the metal ion solution is 0.05 to 0.1 mol / L.

5. The grouting material for shield tunnel foam walls using siltstone slag as described in claim 2, characterized in that, The siltstone containing amino groups on its surface is immersed in a metal ion solution for 20–30 min; the heating procedure for obtaining the pretreated siltstone by vacuum drying is as follows: drying at 25–40 °C for 1–2 h, followed by drying at 40–90 °C for 2–3 h, and finally drying at 90–110 °C for 1–2 h.

6. The grouting material for shield tunnel foam walls using siltstone slag as described in claim 2, characterized in that, The siltstone includes siltstone with a particle size of 0.5 to 2 mm and siltstone with a particle size of 0.1 to 0.25 mm, and the mass ratio of siltstone with a particle size of 0.5 to 2 mm to siltstone with a particle size of 0.1 to 0.25 mm is 1:1 to 3:

2.

7. The grouting material for shield tunnel foam walls using siltstone slag as described in claim 1, characterized in that, The bubble liquid is composed of a mixed foaming agent and water, wherein the mass ratio of the mixed foaming agent to water is 1:10 to 1:20; the mixed foaming agent is a first foaming agent and a second foaming agent mixed in a mass ratio of 1:1, wherein the first foaming agent is one or more of sodium dodecylbenzenesulfonate, sodium dodecyl sulfate, and sodium carbonate, and the second foaming agent is dodecyl dimethylamine oxide.

8. The grouting material for shield tunnel foam walls using siltstone slag as described in claim 1, characterized in that, The cement is PO 42.5 cement, the fly ash is grade I or grade II fly ash, the bentonite is calcium-based bentonite, and the water glass has a Baume degree of 30–40 °Bé.

9. A method for preparing grouting material for shield tunnel foam walls using siltstone slag as described in claim 1, characterized in that, The process includes the following steps: mixing the cement, fly ash, sodium dihydrogen phosphate, bentonite, bubble solution, pretreated siltstone, xanthan gum, and water in the specified amounts to obtain slurry one; before the tunnel boring machine begins excavation, adding the water glass in the specified amounts and stirring at a speed of 80-160 r / min for 3-5 minutes to obtain the final slurry.

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