Preparation method of gold mine tailings-based mine drilling grouting water blocking material

Abstract

The present invention discloses a method for preparing a gold mine tailings-based mine drilling grouting and water blocking material, belonging to the field of mortar preparation. The gold mine tailings and fly ash are dried, finely ground, and sieved; the gold mine tailings, fly ash, UFCC, and sodium fluorosilicate are mixed and stirred to obtain a base material; and sodium lignin sulfonate, CMC, and PAM are added to an alkali activator and stirred to obtain a slurry; the base material and the slurry are mixed and stirred to obtain a grouting and water blocking material. The present invention uses gold mine tailings as the main aggregate, fly ash as the auxiliary aggregate, Na2SiO3 and NaOH as alkali activators, and UFCC as the filler, and prepares the grouting and water blocking material through alkali activation and composite functional additives. The prepared material has good adhesion, strength, impermeability, and durability, and can effectively utilize mine waste, reduce production costs, and reduce environmental pollution. It can be widely used in mine drilling water seepage sealing, broken rock reinforcement, and groundwater prevention and control projects.

Description

Technical Field

[0001] The invention belongs to the technical field of mine mortar preparation, and relates to a method for preparing a gold mine tailings-based drilling grouting water blocking material. Background Art

[0002] During underground mining, water inrush seriously impacts the safety and efficiency of mining operations. Grouting is a fundamental solution to this problem. Traditional grouting materials are generally associated with high cost, unstable performance, and significant environmental impact. They also suffer from slow setting, low compressive strength, and high permeability.

[0003] Gold tailings, a byproduct of the gold mining industry, are typically accumulated in tailings ponds. This massive accumulation not only wastes mineral resources but also pollutes the environment. Left untreated, it occupies significant arable land and generates significant amounts of dust and mining wastewater, seriously contaminating soil and water, posing a threat to the human environment. Utilizing these tailings to create grouting and water-blocking materials could address the tailings disposal challenge while reducing grouting material costs, offering significant economic and environmental benefits. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a method for preparing a gold mine tailings-based mine drilling grouting and water-blocking material, which improves the overall stability and uniformity of the material and enhances the mechanical properties of the material, so that the prepared grouting and water-blocking material has better grouting and water-blocking performance.

[0005] The technical solutions of the present invention are as follows:

[0006] A preparation method for a gold tailings-based mine drilling grouting and water plugging material comprises the following steps: first, drying the gold tailings and fly ash to a moisture content of ≤1%, finely grinding them, and passing them through a 200-mesh sieve; mixing the undersized gold tailings, undersized fly ash, UFCC, and sodium fluorosilicate in a mass ratio of (60-70): (10-20): (5-10): (0.5-1.5) to obtain a base material; adding an alkali activator in an amount of 9-11% by mass of the base material to a stirring container, and then sequentially adding sodium lignin sulfonate in an amount of 0.5%-1% by mass of the base material, CMC in an amount of 0.5%-1% by mass of the base material, and PAM in an amount of 0.1%-0.5% by mass of the base material, and uniformly stirring to obtain a slurry; then mixing all the base material and all the slurry, adding 20%-40% by mass of water to obtain the grouting and water plugging material; wherein the alkali activator is prepared by adding water to NaOH and Na2SiO3.

[0007] Preferably, when preparing the substrate, the mass ratio of undersize gold mine tailings, undersize fly ash, UFCC and sodium fluorosilicate is (64~66): (14~16): (4.5~5.5): (0.8~1.2); when preparing the slurry, the addition ratios of sodium lignin sulfonate, CMC and PAM are 0.7~0.9%, 0.8~1.0% and 0.25~0.35% of the substrate mass, respectively.

[0008] Further preferably, the mass ratio of undersize gold mine tailings, undersize fly ash, UFCC and sodium fluorosilicate is 65:15:5:1; the addition ratios of sodium lignin sulfonate, CMC and PAM are 0.8%, 0.9% and 0.3% of the substrate mass, respectively.

[0009] Preferably, when preparing the substrate, the mass ratio of undersize gold mine tailings, undersize fly ash, UFCC and sodium fluorosilicate is (58~62): (18~22): (9~11): (1.2~1.4); when preparing the slurry, the addition ratios of sodium lignin sulfonate, CMC and PAM are 0.9~1.1%, 0.9~1.1% and 0.45~0.55% of the substrate mass, respectively.

[0010] Further preferably, the mass ratio of undersize gold mine tailings, undersize fly ash, UFCC and sodium fluorosilicate is 60:20:10:1.3; the addition ratios of sodium lignin sulfonate, CMC and PAM are 1.0%, 1.0% and 0.5% of the mass of the substrate respectively.

[0011] Preferably, when preparing the substrate, the mass ratio of undersize gold mine tailings, undersize fly ash, UFCC and sodium fluorosilicate is (60-64): (18-22): (7-9): (1.1-1.3); when preparing the slurry, the addition ratios of sodium lignin sulfonate, CMC and PAM are 0.6-0.8%, 0.6-0.8% and 0.35-0.45% of the substrate mass, respectively.

[0012] Further preferably, when preparing the substrate, the mass ratio of undersize gold mine tailings, undersize fly ash, UFCC and sodium fluorosilicate is 62:20:8:1.2; when preparing the slurry, the addition ratios of sodium lignin sulfonate, CMC and PAM are 0.7%, 0.7% and 0.4% of the substrate mass, respectively.

[0013] Preferably, the alkaline activator is prepared by mixing Na2SiO3 with a NaOH solution having a mass concentration of 2% and standing at room temperature for 18 to 36 hours in a mass ratio of (1 to 1.5):1.

[0014] Preferably, in the slurry preparation step, sodium lignin sulfonate is added in portions to avoid agglomeration; PAM is preliminarily dissolved in water into a colloidal liquid and added dropwise.

[0015] Preferably, during the slurry preparation step, the temperature in the stirring container is ≤ 40° C. to avoid gelation of CMC.

[0016] The main mechanism for preparing the gold tailings-based drilling grouting water-blocking material in this invention is that an alkaline activator activates SiO2 and Al2O3 in the gold tailings and fly ash into active ingredients. Under alkaline conditions, the active ingredients undergo a secondary reaction to form a high-strength gel (such as calcium silicate gel CSH), as shown in the following reaction formula: ; Sodium fluorosilicate can react with calcium ions in gold mine tailings and fly ash under alkaline conditions to form insoluble calcium fluorosilicate precipitate. This precipitate can fill the tiny pores in the material, improving the density and impermeability of the material. The reaction formula is: .

[0017] The long-chain PAM molecules used in this invention bond to the inorganic gel through hydrogen bonds and van der Waals forces, forming a "rigid inorganic phase + flexible organic phase" composite structure. This enhances the material's toughness and resistance to dynamic water erosion, improving its overall stability and uniformity. The CMC used in this invention has excellent thickening and water-retention properties. Through its hydroxyl groups, it binds to the free water in the slurry, acting as a thickener and water-retaining agent in the mixture. This improves the mixture's rheological properties, slows water evaporation, prevents premature hardening of the slurry and incomplete crack filling, and enhances the material's early strength and durability. The sodium lignin sulfonate used in this invention has strong dispersibility and acts as a dispersant in the mixture, preventing particle agglomeration and improving the mixture's fluidity. It also enhances the material's durability. The UFCC used in this invention, as a filler, can fill the micropores in the gel network, reducing the material's permeability and increasing its density and strength. Furthermore, it can react with an alkaline activator to form a calcium carbonate precipitate with a certain strength, further enhancing the material's mechanical properties.

[0018] The gold tailings used in the present invention are primarily derived from the gold ore beneficiation process, specifically waste generated after gold extraction processes such as flotation and cyanidation. Their main components are SiO2 (50-80%), Al2O3 (15-20%), Fe2O3 (5-8%), CaO (1-2%), MgO (0-2%), and K2O (2-4%). Leaching toxicity does not exceed the 5mg / L standard, indicating that gold tailings are general solid waste and can be recycled as a resource. The fly ash used is primarily fine ash captured from flue gas after coal combustion. It is a common solid waste in factories and its main components are SiO2 (40-60%), Al2O3 (20-35%), Fe2O3 (5-15%), and CaO (1-10%).

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] This invention uses gold mine tailings as the primary aggregate, fly ash as the auxiliary aggregate, Na2SiO3 and NaOH as alkali activators, and UFCC as the filler. Alkaline activation and composite functional additives are used to prepare a grouting water-blocking material. The prepared material sets quickly and exhibits excellent adhesion, strength, impermeability, and durability. It also effectively utilizes mining waste, reduces production costs, and minimizes environmental pollution. The prepared grouting water-blocking material can be widely used in mine borehole seepage sealing, fractured rock reinforcement, and groundwater control projects. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is an SEM image of the basic grouting water blocking material prepared in Example 1 of the present invention;

[0022] Figure 2 This is an SEM image of the rapid setting grouting water blocking material prepared in Example 2 of the present invention;

[0023] Figure 3 This is an SEM image of the high-fluidity grouting and water-blocking material prepared in Example 3 of the present invention. DETAILED DESCRIPTION

[0024] The present invention is further described below with reference to examples and experimental data.

[0025] Example 1: Preparation Example 1 of Grouting Water-blocking Material (Basic Type)

[0026] (1) Place the gold mine tailings and fly ash in an oven at 105°C for 24 hours to reduce the moisture content to ≤1%. Sieve to remove large particles of impurities. Use a ball mill to finely grind the sieved gold mine tailings and fly ash, pass through a 200-mesh sieve, and take the sieve product for use.

[0027] (2) Weigh 65 kg of gold mine tailings, 15 kg of fly ash, 5 kg of UFCC and 1 kg of sodium fluorosilicate, pour them into a blender, and stir at 30-40 r / min for 10 min to initially mix and form 86 kg of base material.

[0028] (3) Prepare a 2% by mass NaOH solution, place it in a beaker, seal it with plastic wrap, and let it stand at room temperature for 24 hours before use. Mix Na2SiO3 and the 2% by mass NaOH solution in a mass ratio of 1:1 to prepare an alkaline activator.

[0029] (4) Transfer 8.6 kg of alkaline activator to a stirred tank, and add 688 g of sodium lignin sulfonate, 774 g of CMC, and 258 g of PAM in sequence. Stir continuously at 700-800 r / min for 30 min to evenly distribute all the ingredients and form a slurry of 10.32 kg with a certain fluidity. Sodium lignin sulfonate was added in three portions, with an interval of 3 min between each addition to avoid agglomeration. PAM was pre-dissolved in 5 times distilled water into a colloidal liquid and added dropwise. The temperature in the stirred tank was controlled to ≤40°C to prevent gelation of CMC.

[0030] (5) Add 86 kg of the base material prepared in step (2) to 10.32 kg of the slurry prepared in step (4), add 27 kg of distilled water thereto, adjust the mixer to enter the program-controlled mode for stirring, first stir at 300 r / min for 3 minutes, and then stir at 500 r / min for 5 minutes to form a uniform grouting and water-blocking material.

[0031] Application example 1: Grouting water blocking material application example 1 (basic type)

[0032] (1) Grouting: Start the slurry pump and inject the grouting water-blocking material prepared in Example 1 into a 75 mm borehole at a pressure of 3 MPa. During the grouting process, continuously monitor the pressure change and slurry flow rate to ensure that the slurry can fully fill the cracks and pores.

[0033] (2) Curing and testing: After grouting, the borehole is sealed and cured for 7 days. After curing, the grouting body is cored with a drill. The setting time, compressive strength, and permeability coefficient of the grouting body are measured in accordance with national standards GB / T 1346-2011, GB / T 17671-2021, and ASTM D5084 to evaluate the strength and impermeability of the grouting water blocking material for gold tailings-based mines.

[0034] (3) Test results: The test results show that the initial setting time of the grouting water blocking material prepared in Example 1 is 4.2 min, the final setting time is 8.5 min; the 1d compressive strength is 9.16 MPa, the 7d compressive strength is 16.67 MPa; the permeability coefficient is 2.8×10 - 9 The material exhibits high mechanical properties, no leakage, and can effectively seal cracks with a width of 2 to 5 mm.

[0035] Example 2: Preparation Example 2 of Grouting Water-blocking Material (Rapid Setting Type)

[0036] (1) Same as step (1) of Example 1.

[0037] (2) Weigh 60 kg of gold mine tailings, 20 kg of fly ash, 10 kg of UFCC and 1.3 kg of sodium fluorosilicate, pour them into a blender, and stir at 30-40 r / min for 10 min to initially mix and form 91.3 kg of base material.

[0038] (3) Same as step (3) of Example 1.

[0039] (4) Transfer 9.13 kg of alkaline activator to a stirred tank, and add 913 g of sodium lignin sulfonate, 913 g of CMC, and 456.5 g of PAM in sequence. Stir continuously at 700-800 r / min for 30 min to evenly distribute all the ingredients and form 11.41 kg of slurry with a certain fluidity. Sodium lignin sulfonate was added in three portions, with an interval of 3 min between each addition to avoid agglomeration. PAM was pre-dissolved in 5 times distilled water into a colloidal solution and added dropwise. The temperature in the stirred tank was controlled to ≤40°C to prevent gelation of CMC.

[0040] (5) Add 91.3 kg of the base material prepared in step (2) to 11.41 kg of the slurry prepared in step (4), add 26 kg of distilled water thereto, adjust the mixer to enter the program-controlled mode for stirring, first stir at 300 r / min for 3 minutes, and then stir at 500 r / min for 5 minutes to form a uniform grouting and water-blocking material.

[0041] Application Example 2: Grouting Water Blocking Material Application Example 2 (Quick Setting Type)

[0042] (1) Grouting: Inject the grouting water blocking material prepared in Example 2 into a 75 mm borehole at a pressure of 4 MPa; other operations are the same as step (1) of Application Example 1.

[0043] (2) Maintenance and testing: Same as step (2) of Application Example 1.

[0044] (3) Test results: The test results show that the initial setting time of the gold mine tailings-based drilling grouting water blocking material is 1.5 minutes, the final setting time is 3.8 minutes; the 1-day compressive strength is 13.35 MPa, the 7-day compressive strength is 21.67 MPa; the permeability coefficient is 1.5×10 -9 cm / s. The water-blocking material based on this basic formula exhibits high mechanical properties and is leak-free, making it suitable for drilling scenarios with large water inflows that require rapid sealing.

[0045] Example 3: Preparation of Grouting Water-Plugging Material (High Fluidity)

[0046] (1) Same as step (1) of Example 1.

[0047] (2) Weigh 62 kg of gold mine tailings, 20 kg of fly ash, 8 kg of UFCC and 1.2 kg of sodium fluorosilicate, pour them into a blender, and stir at 30-40 r / min for 10 min to initially mix and form 91.2 kg of base material.

[0048] (3) Same as step (3) of Example 1.

[0049] (4) Transfer 9.12 kg of alkaline activator to a stirred tank, and add 638.4 g of sodium lignin sulfonate, 638.4 g of CMC, and 364.8 g of PAM in sequence. Stir continuously at 700-800 r / min for 30 min to evenly distribute all the ingredients and form a slurry of 10.76 kg with a certain fluidity. Sodium lignin sulfonate was added in three portions, with an interval of 3 min between each addition to avoid agglomeration. PAM was pre-dissolved in 5 times distilled water into a colloidal liquid and added dropwise. The temperature in the stirred tank was controlled to ≤40°C to prevent gelation of CMC.

[0050] (5) Add 91.2 kg of the base material prepared in step (2) to 10.76 kg of the slurry prepared in step (4), add 36 kg of distilled water thereto, adjust the mixer to enter the program-controlled mode for stirring, first stir at 300 r / min for 3 minutes, and then stir at 500 r / min for 5 minutes to form a uniform grouting and water-blocking material.

[0051] Application Example 3: Grouting Water Blocking Material Application Example 3 (High Fluidity Type)

[0052] (1) Grouting: Inject the grouting water-blocking material prepared in Example 3 into a 75 mm borehole at a pressure of 2.5 MPa; other operations are the same as step (1) of Application Example 1.

[0053] (2) Maintenance and testing: Same as step (2) of Application Example 1.

[0054] (3) Test results: The test results show that the initial setting time of the gold mine tailings-based drilling grouting water blocking material is 5.9 minutes, the final setting time is 12.6 minutes; the 1-day compressive strength is 10.83 MPa, the 7-day compressive strength is 19.17 MPa; the permeability coefficient is 3.5×10 -9 The water plugging material based on this basic formula exhibits high mechanical properties, no obvious leakage, and can effectively plug cracks with a width of 0.1-0.5 mm.

[0055] Data Analysis:

[0056] First, the setting time of the material prepared in Example 2 is shorter than that of the material prepared in Example 1. This is because the ratio of sodium fluorosilicate, fly ash and UFCC is increased in Example 2 compared with Example 1. Sodium fluorosilicate is hydrolyzed faster under alkaline conditions to generate SiO2 nanoparticles and F - ions, providing more silicon sources and promoting the rapid precipitation of aluminosilicate gel, significantly shortening the initial setting time; fly ash has higher active SiO2 and Al2O3 contents, which accelerate dissolution under the action of alkali activators, forming a gel network, shortening the reaction induction period; UFCC fills pores, reduces free water content, inhibits the delay of hydration reaction, and accelerates hardening.

[0057] Second, the compressive strength of the material prepared in Example 2 is higher than that of the material prepared in Example 1. This is because, compared with Example 1, the active components of fly ash (SiO2, Al2O3) in Example 2 are increased, generating more NASH gel; the amount of UFCC is doubled, filling the pores and improving the density; sodium fluorosilicate generates CaF2 crystals, enhancing the interfacial bonding strength and improving the overall toughness of the material.

[0058] Third, the permeability coefficient of the material prepared in Example 2 is lower than that of the material prepared in Example 1. This is because, compared with Example 1, UFCC fills the micron-sized pores in Example 2, blocks the permeation channels, and increases the tortuosity of the permeation path; the rapid coagulation of sodium fluorosilicate reduces the water loss of the slurry in a dynamic water environment and avoids the formation of connected pores; the increase in the proportion of fly ash and the enhancement of the alkali excitation reaction form a more continuous and dense aluminosilicate gel network, which reduces the permeability coefficient.

[0059] Fourth, the material prepared in Example 3 has a longer setting time and better fluidity than the material prepared in Example 1. This is because, compared with Example 1, in Example 3, the water-cement ratio is increased, which dilutes the concentration of the reactants and slows down the accelerating coagulant reaction of sodium fluorosilicate and CaCO3; increasing the ratio of fly ash and UFCC, while increasing the source of active silicon and aluminum, weakens the densification effect due to high moisture content and delays the formation of the gel network; supplemented by reducing the grouting pressure (3→2.5MPa), the densification of the slurry is reduced, and ultimately the fluidity of the grouting water-blocking material is improved and the setting time is extended in a synergistic manner.

[0060] Microstructure analysis:

[0061] The microstructure of the grouting and water plugging materials prepared in Example 1 (basic type), Example 2 (rapid setting type) and Example 3 (high fluidity type) was analyzed using the RoqSCANTM rock chip automatic mineral analysis electron microscope jointly developed by Fugro Robertson and Carl Zeiss. The results are shown in Figure 1 、 Figure 2 and Figure 3As can be seen from the SEM images, in the three embodiments of the basic type, rapid setting type, and high fluidity type, various materials such as gold mine tailings and fly ash are tightly bonded together and tightly wrapped by the generated aluminosilicate gel material. The overall bonding is good, the compressive strength is high, and the permeability coefficient is low, which can effectively seal mine drill holes.

[0062] The Na2SiO3 used in the present invention is instant sodium silicate powder with a modulus of 2.0 and a net content of 75%. The NaOH is in solid granular form with a purity of ≥95%.

[0063] The UFCC mentioned in the present invention refers to ultrafine calcium carbonate; the CMC refers to carboxymethyl cellulose; and the PAM refers to polyacrylamide.

Claims

1. A method for preparing a gold mine tailings-based mine drilling grouting water blocking material, characterized in that The preparation steps are as follows: first, the gold mine tailings and fly ash are dried to a moisture content of ≤1%, respectively, and finely ground and passed through a 200-mesh sieve; the undersized gold mine tailings, undersized fly ash, UFCC and sodium fluorosilicate are mixed and stirred in a mass ratio of (60-70): (10-20): (5-10): (0.5-1.5) to obtain a base material; and an alkali activator of 9-11% by mass of the base material is added to a stirring container, and then 0.5%-1% by mass of sodium lignin sulfonate, 0.5%-1% by mass of CMC and 0.1%-0.5% by mass of PAM are added in sequence, and stirred to obtain a slurry; then all the base materials and all the slurry are mixed, and 20%-40% by mass of water after the mixture is added, and stirred to obtain a grouting and water blocking material; wherein the alkali activator is prepared by adding NaOH and Na2SiO3 to water.

2. The method for preparing the gold mine tailings-based mine drilling grouting water blocking material according to claim 1, characterized in that: When preparing the substrate, the mass ratio of undersized gold mine tailings, undersized fly ash, UFCC and sodium fluorosilicate is (64~66): (14~16): (5~5.5): (0.8~1.2); when preparing the slurry, the addition ratios of sodium lignin sulfonate, CMC and PAM are 0.7~0.9%, 0.8~1.0% and 0.25~0.35% of the substrate mass, respectively.

3. The method for preparing the gold mine tailings-based mine drilling grouting water blocking material according to claim 2, characterized in that: The mass ratio of undersized gold mine tailings, undersized fly ash, UFCC and sodium fluorosilicate is 65:15:5:1; the addition ratios of sodium lignin sulfonate, CMC and PAM are 0.8%, 0.9% and 0.3% of the substrate mass, respectively.

4. The method for preparing the gold mine tailings-based mine drilling grouting water blocking material according to claim 1, characterized in that: When preparing the substrate, the mass ratio of undersized gold mine tailings, undersized fly ash, UFCC and sodium fluorosilicate is (60~62): (18~20): (9~10): (1.2~1.4); when preparing the slurry, the addition ratios of sodium lignin sulfonate, CMC and PAM are 0.9~1.0%, 0.9~1.0% and 0.50% of the substrate mass, respectively.

5. The method for preparing the gold mine tailings-based mine drilling grouting water blocking material according to claim 4, characterized in that: The mass ratio of undersized gold mine tailings, undersized fly ash, UFCC and sodium fluorosilicate is 60:20:10:1.3; the addition ratios of sodium lignin sulfonate, CMC and PAM are 1.0%, 1.0% and 0.5% of the substrate mass, respectively.

6. The method for preparing the gold mine tailings-based mine drilling grouting water blocking material according to claim 1, characterized in that: When preparing the substrate, the mass ratio of undersized gold mine tailings, undersized fly ash, UFCC and sodium fluorosilicate is (60~64): (18~20): (7~9): (1.1~1.3); when preparing the slurry, the addition ratios of sodium lignin sulfonate, CMC and PAM are 0.6~0.8%, 0.6~0.8% and 0.35~0.45% of the substrate mass, respectively.

7. The method for preparing the gold mine tailings-based mine drilling grouting water blocking material according to claim 6, characterized in that: When preparing the substrate, the mass ratio of undersized gold mine tailings, undersized fly ash, UFCC and sodium fluorosilicate is 62:20:8:1.2; when preparing the slurry, the addition ratios of sodium lignin sulfonate, CMC and PAM are 0.7%, 0.7% and 0.4% of the substrate mass, respectively.

8. The method for preparing the gold mine tailings-based mine drilling grouting water blocking material according to any one of claims 1 to 7, characterized in that: The preparation method of the alkaline activator is as follows: Na2SiO3 and a NaOH solution with a mass concentration of 2% and allowed to stand for 18 to 36 hours at room temperature are mixed in a mass ratio of (1 to 1.5):

1.

9. The method for preparing the gold mine tailings-based mine drilling grouting water blocking material according to any one of claims 1 to 7, characterized in that: In the slurry preparation step, sodium lignin sulfonate is added in batches to avoid agglomeration; PAM is pre-dissolved in water into a colloidal liquid and added dropwise.

10. The method for preparing the gold mine tailings-based mine drilling grouting water blocking material according to any one of claims 1 to 7, characterized in that: During the slurry preparation step, the temperature in the stirring container was ≤ 40°C to avoid gelation of CMC.

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