Solid stemming with high CO adsorption performance and application thereof

Abstract

According to the solid stemming with the high CO adsorption performance and the application of the solid stemming, modified sepiolite is adopted as a core functional component, natural sepiolite is modified through an acidification-hydrothermal-copper loading triple process, the specific surface area, the pore volume and the surface active site density of the solid stemming are remarkably increased, and the CO adsorption performance is improved; the solid stemming is endowed with efficient physical and chemical adsorption capacity on CO molecules. At the moment of blasting, the blasthole plugging material is crushed and dispersed along with high-pressure airflow, and the modified sepiolite micro powder is diffused in the underground space after blasting, so that escaping CO gas can be quickly captured and fixed, the forced ventilation and smoke discharge time is shortened, and the roadway tunneling efficiency is improved. And by controlling the concentration of the saline solution and the ratio of the modified sepiolite to the saline solution, the solid stemming has good plasticity and dispersity, is convenient for underground operation and is not easy to bond, and the construction efficiency is improved.

Description

[Technical Field] This invention belongs to the field of solid potting clay technology, and particularly relates to a solid potting clay with high CO adsorption performance and its application. [Background Technology] Underground blasting operations are a crucial process in underground engineering construction such as mining and tunneling, and their safety directly affects construction efficiency and the health and lives of workers. However, blasting inevitably produces a large amount of fumes, among which carbon monoxide (CO) is the most toxic and harmful gas. CO is colorless and odorless, but extremely toxic. Inhalation can easily cause acute poisoning, ranging from mild respiratory irritation and bronchitis to severe toxic pneumonia, pulmonary edema, and even cerebral edema, which can be fatal in severe cases.

[0003] Currently, underground blasting relies mainly on forced ventilation to dilute and remove blasting fumes. However, in situations such as narrow tunnels, complex ventilation paths, or tight work schedules, ventilation efficiency is limited, which can easily lead to localized accumulation of blasting fumes and create significant safety risks.

[0004] To improve the effectiveness of blasting sealing and assist in smoke control, existing technologies generally employ a combination of "water-based drilling mud" and "solid drilling mud" for borehole sealing. Solid drilling mud is typically made from a mixture of drill cuttings, loess, or sand. While it offers advantages such as low cost and ease of preparation, its material composition is essentially ordinary clay minerals with a small specific surface area and underdeveloped pore structure, resulting in virtually no adsorption or catalytic conversion capacity for harmful gases such as CO. This means that the high-temperature, high-pressure gases and dust released during blasting cannot be effectively trapped or purified; instead, the material's inertness exacerbates underground air pollution, prolongs ventilation waiting time, and hinders tunneling efficiency and operational safety. [Summary of the Invention] The purpose of this invention is to provide a solid blasting mud with high CO adsorption performance, which solves the problem that the high-temperature and high-pressure gases and dust released during blasting cannot be effectively intercepted or purified.

[0006] This invention is achieved by the following technical solution: A solid potting mud with high CO adsorption capacity, comprising the following components by weight: 4 parts of modified sepiolite; 1 part salt water; The water content of the solid gunning clay is 20%.

[0007] This invention utilizes modified sepiolite as the core functional component in solid borehole sealing material, providing high specific surface area, pore volume, and surface active sites to achieve efficient physicochemical adsorption of CO. At the moment of blasting, the borehole sealing material breaks down and disperses with the high-pressure airflow, and the modified sepiolite powder diffuses into the underground space after blasting, rapidly capturing and fixing the escaped CO gas, thereby shortening the forced ventilation smoke extraction time and improving tunnel excavation efficiency. Secondly, brine is used as an auxiliary component. On the one hand, it enhances the plasticity of the sealing material, ensuring dense filling and reliable sealing, preventing premature leakage of blast gas; on the other hand, Na⁺ and Cl⁻ ions enhance the ion exchange capacity of the material surface, assisting in the adsorption of polar gas molecules such as CO, and promoting surface reactions under the high-temperature environment of blasting, synergistically suppressing dust dispersion and promoting the sedimentation of gaseous pollutants. Furthermore, by optimizing the moisture content of the solid borehole sealing material, it avoids brittle sealing failure due to excessive moisture, while preventing strength reduction or delayed drying due to excessive moisture, ensuring the structural integrity and performance stability of the material throughout the filling, blasting, and purification processes.

[0008] Preferably, the method for preparing the modified sepiolite includes the following steps: S1. Acidification: Sepiolite is immersed in HCl solution and stirred continuously to obtain an acidification product. The acidification product is washed with deionized water until the pH of the filtrate is neutral. The acidification product is then dried to obtain acidified sepiolite. S2, hydrothermal: The acidified sepiolite described in step S1 is mixed and stirred with deionized water. After stirring, it is transferred to a reaction vessel and placed in an oven for hydrothermal reaction to obtain acidified-hydrothermal sepiolite. S3. Loading: The acidified-hydrothermal sepiolite described in step S2 is immersed in a copper-containing solution and stirred continuously. After filtration and drying, it is calcined under nitrogen to obtain modified sepiolite.

[0009] This invention uses modified sepiolite as the core functional component. Natural sepiolite is modified through a triple process of acidification-hydrothermal-copper loading, which significantly improves its specific surface area, pore volume and surface active site density, giving solid potting mud a highly efficient physicochemical adsorption capacity for CO molecules.

[0010] Sepiolite, a natural layered chain silicate mineral, is inexpensive and environmentally friendly. It boasts the largest specific surface area among non-metallic minerals and a unique nanoscale tunnel structure, making it a recognized clay mineral with the strongest adsorption capacity. It also possesses excellent thermal insulation (withstanding temperatures up to 1500–1700℃) and flame retardancy, effectively suppressing the ejection of blasting flames and high-temperature particles, reducing the risk of gas and coal dust explosions. Furthermore, its high water absorption rate allows it to absorb heat and evaporate during blasting, further inhibiting the ignition of flammable gases.

[0011] Specifically, sepiolite was acidified and modified using HCl solution, through H...+ It preferentially reacts with CaCO3, effectively dissolving non-framework minerals and achieving selective purification, thereby improving the purity of sepiolite; on the other hand, the H in HCl... + It can react with Mg in the magnesium-oxygen octahedron of sepiolite 2+ The reaction will cause Mg in the Si-O-Mg-O-Si structure to react. 2+ The displacement disrupts the local crystal lattice, turning the originally closed or semi-closed channels at both ends of the magnesium-oxygen octahedron into an "open" structure, allowing the internal channels to connect with each other, generating more micropores, thereby increasing the specific surface area and providing abundant physical adsorption sites for CO molecules.

[0012] Acid-modified sepiolite develops numerous microcracks and open pores due to dissolution. Low-to-medium temperature hydrothermal treatment promotes the dehydration condensation reaction of silanol groups (Si-OH), repairing local skeletal defects and forming a more stable mesoporous structure. The hydrothermal process also removes physically adsorbed structural water from the sepiolite, while simultaneously promoting the dissociation and dispersion of sepiolite nanofiber bundles, clearing blocked internal micropore channels, and further increasing the effective specific surface area and pore volume.

[0013] Acid-treated and hydrothermally modified sepiolite has a larger specific surface area and more developed pores, which can effectively promote the physical adsorption of CO, while also being a precursor for CuO. x The load provides more anchoring points. During the acidification stage, the HCl solution selectively dissolves Mg from the sepiolite magnesium oxide octahedral (Si-O-Mg-O-Si) structure through proton exchange. 2+ Mg forms in the crystal lattice 2+ Vacancy defects can effectively promote subsequent Cu + The displacement of Cu in the copper-containing solution during copper loading. 2+ It can efficiently replace Mg 2+ Vacancies, some Cu 2+ An embedded sepiolite silica-oxygen framework forms a strongly chemically bonded anchoring structure. Simultaneously, the residual negative charge on the acidified material surface effectively inhibits the migration and aggregation of Cu species during loading through electrostatic repulsion; while the well-developed nanoporous structure provides steric hindrance, further constraining the size of Cu nanoparticles and achieving CuO. x The highly dispersed and stable loading. In addition, under the residual heat environment after the explosion, some Cu species can catalyze the oxidation of CO to CO2, realizing a triple purification pathway of "adsorption → activation → conversion".

[0014] Preferably, the sepiolite in step S1 is β-sepiolite, which is layered or massive.

[0015] This invention uses β-type sepiolite as the modified substrate, which is layered and massive in form. Microscopically, it is composed of numerous extremely fine, short-range ordered nanofibers or fiber bundles interwoven to form a highly developed tunnel-like pore system and interlayer microporous structure. This unique multi-scale pore network endows it with naturally excellent physical adsorption properties. Compared to α-type, β-type sepiolite has an ordered layered silica-oxygen framework and a uniform distribution of magnesium-oxygen octahedrons, making it easier to selectively dissolve Mg during acid treatment. 2+ Without damaging the main framework, it ensures a balance between pore expansion and structural stability; it has higher structural heat resistance, and is less prone to phase transition or structural collapse under subsequent hydrothermal treatment and transient high-temperature environments, ensuring that functional components remain active; and Mg in the β-type 2+ The content and distribution are more conducive to H + / Cu 2+ Gradient substitution provides a structural basis for constructing high-density, high-stability active sites.

[0016] Preferably, the concentration of the HCl solution in step S1 is 3 mol / L.

[0017] Preferably, the solid-liquid ratio of sepiolite to HCl solution in step S1 is 1:10 (g / mL); and the acidification temperature is 60°C.

[0018] Among them, such as Figure 1 As shown, the adsorption performance of acidified sepiolite for CO initially increases and then decreases with increasing temperature, reaching its optimal level at 60℃, where the lowest CO concentration at the outlet can be reduced to 71.7 ppm. When the acidification temperature rises to 80℃, the adsorption performance significantly decreases. At low temperatures (<60℃), the reaction rate is low, resulting in insufficient dissolution of mineral impurities by the acid solution. Increasing the acidification temperature provides more energy for the acidification reaction, effectively promoting the formation of porous structures. When the temperature rises to 60℃, hydrochloric acid (HCl) can effectively disrupt the layered structure of sepiolite, increasing its specific surface area and significantly improving its porosity, thus synergistically enhancing its CO adsorption capacity. However, excessively high temperatures (>60℃) easily lead to pore structure collapse or pore fusion, resulting in decreased adsorption performance.

[0019] Preferably, the solid-liquid ratio of the acidified sepiolite to deionized water in step S2 is 1:8 (g / mL).

[0020] Preferably, the copper-containing solution in step S3 includes CuCl2·2H2O and Cu(CH3COO)2·H2O.

[0021] This invention uses a mixed solution of copper chloride (CuCl2·2H2O) and copper acetate (Cu(CH3COO)2·H2O) as the copper source. Through Cl... -Its strong coordination ability and surface activation effect preferentially interact with Si-OH or defect sites on the sepiolite surface, exposing more anchoring sites and promoting Cu 2+ The replacement efficiency, while Cl - Able to interact with Cu 2+ Formation of soluble complexes, delaying Cu 2+ Hydrolysis in near-neutral or weakly acidic impregnation solutions. (By CH3COO) - The complexation effect can be combined with Cu 2+ Formation of dynamically reversible complexes, slowing down Cu 2+ The release rate avoids rapid nucleation and aggregation caused by excessively high local concentrations; it also forms a spatial barrier around Cu through its steric hindrance, physically preventing particle collisions and aggregation, thus improving dispersion stability. During calcination under nitrogen protection, CH3COO... - Pyrolysis produces reducing gases. In an oxygen-deficient environment, Cu... 2+ Reduced to Cu + Cu + The strong interaction between Cu and CO molecules through d-π back bonds significantly enhances anchoring ability. Meanwhile, Cu... + It exhibits a strong tendency for covalent bonding, which enhances the rigidity of the framework, thereby effectively suppressing structural deformation during the adsorption process after explosion, and ensuring stable adsorption of CO molecules at the active sites. Compared to unmodified sepiolite, the adsorption configuration of the Cu-modified system is more stable.

[0022] Preferably, the molar ratio of CuCl2·2H2O to Cu(CH3COO)2·H2O is 1:1.5.

[0023] Preferably, the copper loading of the modified sepiolite in step S3 is 10%.

[0024] Preferably, the purity of the nitrogen gas in step S3 is ≥99.99%.

[0025] Preferably, the concentration of the saline solution is 2-3%.

[0026] The present invention also aims to provide an application of solid blasting mud with high CO adsorption performance in underground space tunneling and blasting.

[0027] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention's solid drilling mud uses modified sepiolite as its core functional component. Through a triple process of acidification, hydrothermal treatment, and copper loading, natural sepiolite is modified, significantly increasing its specific surface area, pore volume, and surface active site density, thus endowing the solid drilling mud with highly efficient physicochemical adsorption capacity for CO molecules. At the moment of blasting, the borehole sealing material breaks down and disperses with the high-pressure airflow, and the modified sepiolite powder diffuses into the underground space after blasting, rapidly capturing and fixing the escaped CO gas, thereby shortening the forced ventilation smoke extraction time and improving tunnel excavation efficiency. Furthermore, by controlling the concentration of brine and the modified sepiolite-salt water ratio, the water content of the solid drilling mud is stabilized at around 20%, exhibiting good plasticity and dispersibility, facilitating underground operation, preventing adhesion, and improving construction efficiency. [Attached Image Description] Figure 1 Figure 1 shows the CO adsorption results of sepiolite modified at different acidification temperatures.

Detailed Implementation Methods

[0030] The preparation method of solid pipe clay includes the following steps: Mix 6g of modified sepiolite with 1.5g of 2-3% saline solution to obtain solid potting mud with high CO adsorption performance.

[0031] Comparative Example 1 The preparation method of solid pipe clay includes the following steps: Mix 6g of natural sepiolite with 1.5g of 2-3% saline solution to obtain solid potting mud.

[0032] Comparative Example 2 The preparation method of acidified sepiolite includes the following steps: 10g of sepiolite was immersed in 100mL of 3mol / L HCl solution and stirred continuously at 60℃ for 4h to obtain an acidified product. The acidified product was washed with deionized water until the pH of the filtrate was neutral. The acidified product was then dried to obtain acidified sepiolite.

[0033] The preparation method of solid pipe clay includes the following steps: Mix 6g of acidified sepiolite with 1.5g of 2-3% saline solution to obtain solid potting mud.

[0034] Comparative Example 3 The preparation method of acidified-hydrothermal sepiolite includes the following steps: S1. Acidification: 10g of sepiolite was immersed in 100mL of 3mol / L HCl solution and stirred continuously at 60℃ for 4h to obtain an acidification product. The acidification product was washed with deionized water until the pH of the filtrate was neutral. The acidified product was then dried to obtain acidified sepiolite. S2, hydrothermal: Mix 10g of the acidified sepiolite described in step S1 with 80mL of deionized water and stir for 0.5h. After stirring, transfer the mixture to a 100mL reaction vessel and place it in an oven at 120℃ for hydrothermal reaction for 10h to obtain acidified-hydrothermal sepiolite. The preparation method of solid pipe clay includes the following steps: Mix 6g of acidified-hydrothermal sepiolite with 1.5g of 2-3% saline solution to obtain solid potting mud.

[0035] Comparative Example 4 Comparative Example 4 is a traditional solid potting clay, composed of a mixture of loess and sand and 2%–3% saline solution.

[0036] The sepiolite samples from Example 1 and Comparative Examples 1-4 were subjected to performance testing under the following conditions: Testing equipment: fixed-bed reactor, multi-functional gas analyzer.

[0037] Test conditions: 6g of ground and sieved sepiolite was placed in the quartz tube of a fixed-bed reactor. Simulated gas of 105ppm CO + 20% O2 + N2 was introduced at 500mL / min. The CO concentration change was monitored in real time using a multi-functional gas analyzer, and the adsorption efficiency of each sepiolite for CO was calculated.

[0038] Test results are shown in Table 1.

[0039] Table 1 CO adsorption efficiency of Example 1 and Comparative Examples 1-4

[0040] As shown in Table 1, Example 1 exhibits a CO adsorption efficiency as high as 98.24%, indicating that the solid gun clay of this invention possesses excellent CO purification performance in simulated blasting environments. This effect stems from the significantly optimized porous structure of the modified sepiolite after acidification-hydrothermal-copper loading synergistic modification, and the highly dispersed Cu enrichment on its surface. + The active sites can interact with the CO released during the explosion, effectively adsorbing and absorbing CO.

[0041] Compared to Example 1, Comparative Example 1 used unmodified natural sepiolite, which, due to its small specific surface area and limited pore volume, had a CO adsorption efficiency of only 18.00%. Comparative Example 2 used only acid-modified sepiolite; although the acid dissolution produced some porosity, the local structural defects were severe, the framework stability was poor, and there was a lack of active sites, resulting in a still low CO adsorption efficiency of 31.70%. Comparative Example 3 used acid-hydrothermal sepiolite, which repaired and stabilized the pore structure, providing a good physical adsorption basis. However, because it did not load Cu, it could not achieve directional loading of Cu active sites, and the CO adsorption efficiency only increased to 38.80%. Comparative Example 4 was a traditional solid gunning clay, which had virtually no CO adsorption capacity.

[0042] The above examples are merely illustrative of the technical content of the present invention to facilitate easier understanding by the reader, but do not imply that the implementation of the present invention is limited to these examples. Any technical extensions or re-creations made based on the present invention are protected by the present invention. The scope of protection of the present invention is defined by the claims.

Claims

1. A solid quoin having a high CO adsorption performance, characterized by: By weight parts, including the following components: Modified sepiolite 4 parts; Salt water 1 part; The water content of the solid stemming is 20%.

2. The solid quoin having a high CO adsorption performance according to claim 1, characterized by: The preparation method of the modified sepiolite comprises the following steps: S1, acidification: immerse sepiolite in HCl solution with continuous stirring to obtain acidification product, wash the acidification product with deionized water until the filtrate pH is neutral, and dry the acidification product to obtain acidified sepiolite; S2, hydrothermal: mix the acidified sepiolite of step S1 with deionized water and stir, then transfer to a reaction kettle and place in an oven for hydrothermal reaction to obtain acidification-hydrothermal sepiolite; S3, loading: immerse the acidification-hydrothermal sepiolite of step S2 in a copper-containing solution with continuous stirring, filter, dry, and calcine under nitrogen after drying to obtain modified sepiolite.

3. The solid quoin having a high CO adsorption performance according to claim 2, characterized by: The sepiolite of step S1 is β-sepiolite in layered or massive form; the concentration of the HCl solution is 3 mol / L.

4. The solid quoin having a high CO adsorption performance according to claim 2, characterized by: The solid-liquid ratio of the sepiolite of step S1 to HCL solution is 1:10 (g / mL); the acidification temperature is 60°C.

5. The solid quoin having a high CO adsorption performance according to claim 2, wherein: The solid-liquid ratio of the acidified sepiolite of step S2 to deionized water is 1:8 (g / mL); the hydrothermal temperature is 120°C.

6. The solid quoin having a high CO adsorption performance according to claim 2, wherein: The copper-containing solution of step S3 includes CuCl2·2H2O and Cu(CH3COO)2·H2O.

7. The solid quoin having a high CO adsorption performance according to claim 6, characterized by: The molar ratio of CuCl2·2H2O to Cu(CH3COO)2·H2O is 1:1.

5.

8. The solid quoin having a high CO adsorption performance according to claim 1, wherein: The copper loading of the modified sepiolite of step S3 is 10%.

9. The solid quoin having a high CO adsorption performance according to claim 1, wherein: The concentration of the salt water is 2-3%.

10. The application of the solid stemming with high CO adsorption performance according to any one of claims 1-9 to underground space tunneling blasting.

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