Bentonite composite mineral gel, its preparation method and application

Abstract

The application discloses a preparation method of bentonite composite mineral gel, which comprises the following steps: (1) pulp preparation, viscosity reduction and purification; (2) gelation activation; (3) functional group modification; (4) gelation; and (5) atomization, drying and dehydration, so that the bentonite composite mineral gel with high viscosity and high dispersing performance is finally obtained. The technical scheme of the application is that the viscosity is first reduced to increase the concentration of the ore pulp, then an activator is added to increase the viscosity, and at the same time, in order to maintain the dispersing performance, an organic ester modifier is used to modify the montmorillonite inorganic matrix, so that a combined structure of the organic matrix-modifier-inorganic matrix is formed, the inorganic mineral gel obtained through the final bentonite-montmorillonite combination has extremely strong hydrophobic performance, and thus has high viscosity and high dispersing performance. The application can be applied to water-based paint and pesticide as a thickening and suspending agent.

Description

Technical Field

[0001] This invention relates to the field of inorganic mineral gel technology, specifically to a high-performance bentonite composite mineral gel, its preparation method, and its applications. Background Technology

[0002] Bentonite inorganic gel is a natural inorganic gel product with a certain purity, obtained from clay minerals (such as montmorillonite, bentonite, and saponin) containing bentonite inorganic gel components. The process involves raw material crushing, pulping, separation and purification, gelation, and drying. Bentonite inorganic gel has a unique layered magnesium aluminum silicate structure, with Na+ mainly distributed between the layers. + When dispersed in aqueous solution, it forms a unique "carousel-like" structure, exhibiting excellent suspension, rheological properties, and colloidal properties, and has wide applications in toothpaste, cosmetics, coatings, pharmaceuticals, and other fields.

[0003] Bentonite inorganic gels have wide applications in pesticides and coatings. However, existing bentonite inorganic gel technologies have their limitations. Firstly, their strong hydrophilicity leads to rapid hydration in pesticide and coating systems, causing powder agglomeration and severely limiting their use in applications requiring rapid dispersion of adjuvants. Secondly, traditional purification methods for high-viscosity minerals like bentonite typically result in low concentrations, leading to high drying costs and necessitating increased concentrations, optimized equipment, and reduced costs. Furthermore, their viscosity and suspension rates are often poor.

[0004] The conventional wet purification process, commonly used in existing technologies, reduces the viscosity of the slurry by adding dispersants to accelerate gel dispersion and improve dispersion performance, thereby achieving a high slurry concentration and solving the problem of difficult gel drying. However, the dispersant first introduces Na... + This disrupts the surface charge balance of the layered structure of magnesium aluminosilicates, destroying the "carousel-like" structure, leading to a decrease in viscosity and suspension performance, and even loss of gel morphology. Secondly, the concentration of the slurry obtained by this method is approximately 3-4%, which presents significant challenges for subsequent drying processes. Therefore, existing technologies suffer from the limitation of being unable to simultaneously achieve high-concentration slurry and gel viscosity properties, and also face the technical problem of not being able to obtain high viscosity even with high dispersion performance.

[0005] Chinese invention patent CN112569877A discloses a modified bentonite inorganic gel, its preparation method, and its application. This patent uses attapulgite and / or sepiolite as inorganic minerals to composite-modify bentonite, thereby improving the gel's dispersion speed in aqueous systems. However, this modified bentonite inorganic gel exhibits poor viscosity and suspension properties. In particular, the high viscosity of the bentonite slurry during production leads to poor dispersibility and extreme unevenness, making it difficult to achieve uniform mixing when attapulgite is added and stirred, thus affecting the gel's performance. Furthermore, the slurry still suffers from low concentration, slow drying process, and high energy consumption. Summary of the Invention

[0006] The purpose of this invention is to provide a bentonite composite mineral gel, its preparation method, and its application. By combining it with other minerals, the synergistic effect between the minerals is utilized to improve the dispersion performance of the gel, while also increasing its viscosity and suspension performance. This gel can be used as an environmentally friendly thickening and suspending agent in water-based coatings and pesticides.

[0007] To achieve the above objectives, the present invention provides a method for preparing bentonite composite mineral gel, comprising the following steps: (1) pulping, viscosity reduction and purification; (2) gelling activation; (3) functional group modification; (4) gelation; (5) atomization drying and dehydration, and finally obtaining bentonite composite mineral gel with high viscosity and high dispersibility.

[0008] Specifically, it includes the following steps:

[0009] (1) Pulping: Bentonite is dispersed in water to form a coarse slurry;

[0010] (2) Viscosity reduction and slurry preparation: Add viscosity reducer to coarse slurry, stir and mix evenly, and then slurry to obtain a highly dispersible mineral slurry with a concentration of 11-15%;

[0011] (3) Centrifugal purification: The slurry is separated by centrifugation using a dynamic centrifuge. The lower layer of slurry is taken as the purified slurry, and its solid content is 8-12%.

[0012] (4) Gelatinization activation: Add inorganic salts to increase the viscosity of the slurry. The amount of inorganic salts added is 0.5-2%.

[0013] (5) Functional group modification: Organic ester modifiers are added to the slurry to improve the hydrophobic properties of the inorganic montmorillonite body. The amount of organic ester modifier added is 0.1-1%.

[0014] (6) Gelation: Add attapulgite, stir and mix evenly, and then age;

[0015] (7) Atomization drying and dehydration to obtain bentonite composite mineral gel with high viscosity and high suspension performance;

[0016] The mass ratio of montmorillonite to attapulgite is 4:1 to 10:1.

[0017] Preferably, the viscosity reducer in step (2) is either sodium hexametaphosphate or sodium pyrophosphate.

[0018] Preferably, the inorganic salt in step (4) is Na. + Mg 2+ Al 3+ Ca 2+ K + At least one of the following. More preferably, the inorganic salt is Al. 3+ .

[0019] Preferably, the organic ester modifier in step (5) is an organic ester hydrophobic modifier, which forms an inorganic matrix bonding layer with montmorillonite to obtain an organic matrix-organic ester modifier-inorganic matrix bonding layer, thereby improving the hydrophobic properties of the inorganic matrix. Further, the organic ester hydrophobic modifier is an organosilicon or titanate coupling agent.

[0020] Preferably, the atomizing equipment used in step (6) includes an atomizing disc with a diameter of 215-280 cm and a linear velocity of 140-180 m / s. The high-speed rotation disperses the high-viscosity slurry into a mist. Because the slurry has high concentration and high viscosity due to the reactivation of its gelling properties, it easily adheres to the atomizing tower wall. Traditional atomizing discs cannot solve this problem. This invention uses a combination of a large-diameter, slightly backward-inclined atomizing disc and a tower diameter of 110-130%, successfully solving the problems of difficult atomization and severe material adhesion to the tower wall. The high-viscosity slurry is evenly delivered to the edge of the atomizing disc under centrifugal force using a large-size, high-speed atomizing disc, and then the slurry is thrown out. Droplets are horizontally ejected from the atomizing disc, thus dispersing into a mist composed of fine droplets, thereby rapidly drying the slurry at a high temperature of 100-120°C.

[0021] The bentonite composite mineral gel prepared using the above technical solution is a binary mineral gel composed of montmorillonite and attapulgite, with bentonite as the main component and attapulgite as the auxiliary component. The mass ratio of montmorillonite to attapulgite is 4:1 to 10:1, and attapulgite molecules are dispersed in the interstices of montmorillonite molecules. The montmorillonite and attapulgite molecules are stacked to form a rod-plate tower structure. It exhibits high viscosity and high dispersibility, with a viscosity ≥2200 MPa·s and a dispersion time of 5–7 min.

[0022] The montmorillonite to attapulgite mass ratio of this invention is 3:1 to 12:1. When the mass ratio is 4:1 to 10:1, it exhibits excellent viscosity, suspension, and dispersion properties, with a mass ratio of 9:1 being the optimal embodiment. However, when the mass ratio of montmorillonite to attapulgite is 3:1 and 12:1, it exhibits poor viscosity and dispersion properties, and the suspension properties also deteriorate. The reason for this is that only when the attapulgite is reduced to the point where it can only be dispersed in the gaps between the montmorillonite molecules, preventing the orderly stacking of montmorillonite flake molecules, and allowing the flakes and rods to overlap layer by layer, can the dispersion be relatively uniform. In particular, when the ratio of montmorillonite to attapulgite molecules reaches 9:1, the montmorillonite and attapulgite molecules overlap to form a rod-flake tower structure, where the two molecules are completely dispersed and have the best support and connection structure, thus exhibiting excellent physical properties externally. When the mass ratio of montmorillonite to attapulgite is 3:1 or even lower, a large number of rod-shaped crystals are dispersed between the plate-like montmorillonite molecules. Its cavitation structure is relatively collapsed, and it appears to have high dispersion performance, but its viscosity and suspension performance are very poor.

[0023] When the mass ratio reaches 12:1 or even higher, although a karat structure can still be formed due to insufficient attapulgite molecules, the structure contains a large number of excess montmorillonite molecules. The platy montmorillonite molecules easily stack, and the stacked attapulgite rods are radially dispersed around the montmorillonite rods. Only when the number of attapulgite molecules is sufficiently reduced can the rods and montmorillonite molecules form a stacked structure, creating a rod-plate interlocking structure. This results in a high apparent viscosity, but very poor dispersion and suspension properties.

[0024] When the ratio is between 4:1 and 10:1, the montmorillonite platy molecules and rod-shaped molecules can maintain a balance, forming a balanced rod-plate tower structure, thus exhibiting better overall performance in appearance.

[0025] When bentonite is dispersed in water, it forms a suspension of montmorillonite particles. Each montmorillonite particle forms a charged bentonite colloidal particle. Under the influence of electrostatic attraction, an ion layer with opposite charge is formed around the colloidal particle, forming a double electron layer. This makes the montmorillonite suspension very stable and difficult to precipitate, making it difficult to achieve the desired purification effect. As a result, the concentration of the slurry is extremely low, which brings great difficulties to the subsequent drying process. Therefore, it is necessary to increase the concentration of the slurry to reduce the difficulty of drying.

[0026] Meanwhile, attapulgite has a dispersing effect on montmorillonite. When montmorillonite is dispersed in water, it undergoes lamellar peeling under shear force. However, when the shear force is stopped, the lamellars tend to recombine. At this time, due to the presence of attapulgite, the attapulgite rod crystals are dispersed between the montmorillonite lamellars, preventing the lamellars from recombinizing. Since the single-component montmorillonite sample does not have this blocking effect, most of the montmorillonite lamellars eventually recombine to form lamellar crystals, which are very easy to agglomerate and difficult to disperse, which is not conducive to the drying of the gel.

[0027] This invention increases the concentration of the slurry by adding a dispersant, such as sodium pyrophosphate and / or sodium hexametaphosphate. This dispersant disrupts the "I"-shaped association structure formed by montmorillonite in an aqueous medium and utilizes impinging flow to fully hydrate the bentonite. This causes fine-particle solid impurities to lose their support and separate from the montmorillonite, thereby altering the rheological properties of the slurry, reducing its viscosity, and improving its dispersibility. This allows for rapid purification during centrifugal dispersion, resulting in a high-concentration slurry. This also reduces the difficulty of subsequent drying processes.

[0028] However, while adding sodium pyrophosphate / sodium hexametaphosphate as a dispersant to accelerate the dispersion rate of the gel, the introduction of Na... + Disruption of the surface charge balance of the layered structure of magnesium aluminum silicate in montmorillonite disrupts the rod-sheet tower structure, leading to a decrease in viscosity and suspension performance, which in turn reduces gel performance, making it impossible to form a gel structure.

[0029] To further address this problem, this invention reactivates the gelation properties of the slurry by adding inorganic salts, thereby improving viscosity and suspension properties. The inorganic salts primarily include Li. + Na + K + Ca 2+ Mg 2+ Al 3+ Inorganic salts containing metal ions are used to adjust the typical and double-electron-layer structure of the inorganic montmorillonite matrix, restoring the slurry to a stable montmorillonite suspension, maintaining system equilibrium, and facilitating subsequent gelation with attapulgite to form a gel structure with a three-dimensional structure. Among the inorganic salts, Al is the most important. 3+ Optimal performance.

[0030] This invention also improves the dispersibility of the gel by adding organic ester modifiers. Because after the initial processing, while the concentration of the slurry is increased, its dispersibility is similar to that of montmorillonite in the coarse slurry, making it prone to agglomeration and hindering dispersion.

[0031] Therefore, this invention adds an organic ester dispersant to enhance the hydrophobicity of montmorillonite inorganic matter, thereby making it inherently hydrophobic and improving its dispersibility, preventing agglomeration. Hydrophobic organic ester modifiers mainly include organosilicon or / or silicotitanium ester coupling agents, or other reagents with similar functions. One end of these agents can bind to the inorganic matrix, while the other end has a hydrophobic organic group, which modifies the surface of the mineral gel and improves the dispersibility of the mineral additive material. Taking silane coupling agents as an example, one end of the organosilicon reacts with the mineral matrix to form an inorganic matrix binding layer, while the other end is hydrophobic, thus forming an organic matrix-silane coupling agent-inorganic matrix binding layer. The organic matrix possesses hydrophobic properties. After montmorillonite inorganic matter and attapulgite are gelled to form bentonite composite mineral gel, attapulgite molecules are dispersed in the gaps between montmorillonite molecules. Montmorillonite and attapulgite molecules are stacked to form a rod-plate tower structure. In the organic matrix-silane coupling agent-inorganic matrix bonding layer, one end of the organic matrix is ​​attached to the montmorillonite inorganic matter, and the other end crosses within the rod-plate tower structure, forming hydrophobic properties. This allows for rapid dispersion of the bentonite composite mineral gel in water, improving its dispersion performance. This invention is not limited to the aforementioned organic ester modifiers; any modifier capable of achieving this function can be used in this invention.

[0032] Finally, because the bentonite gel of this invention has high concentration, high viscosity, and high suspension properties, its drying process differs from the drying process of low-concentration, high-viscosity composite clays in traditional technologies. The main technical challenge lies in its high viscosity. This invention employs a high-speed, large-diameter atomizing disc to address this issue. Thus, an inorganic composite mineral gel with high viscosity, high dispersibility, and excellent suspension properties is ultimately obtained.

[0033] The bentonite composite mineral gel prepared by this invention has excellent comprehensive properties and can be applied to the pesticide, coating and detergent industries.

[0034] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art:

[0035] 1. This invention employs a "suppress then enhance" technique: first, the viscosity is reduced to increase the concentration of the slurry; then, an activator is added to further increase its viscosity. Simultaneously, to maintain its dispersibility, an organic ester modifier is used to modify the montmorillonite inorganic matrix, forming a combined structure of organic matrix-modifier-inorganic matrix. This results in an inorganic mineral gel obtained from the final bentonite-montmorillonite composite exhibiting extremely strong hydrophobic properties, thus possessing high viscosity, high dispersibility, and excellent suspension properties. It can be used as an environmentally friendly thickening and suspending agent in water-based coatings and pesticides, demonstrating superior performance compared to similar products in the prior art.

[0036] 2. The technical solution of the present invention is simple to operate. The large-diameter, high-speed atomizing disc used solves the drying problem of high-viscosity slurry. It can be used not only in the technical solution of the present invention, but also in other high-viscosity slurry products, which has groundbreaking creative significance. Attached Figure Description

[0037] Figure 1 This is a flowchart of the preparation process in Example 1 of the present invention. Detailed Implementation

[0038] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the specific content of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present invention.

[0039] This invention provides a bentonite composite mineral gel with high viscosity and high dispersibility. Its preparation method includes the following steps: (1) pulping, viscosity reduction and purification; (2) gelling activation; (3) functional group modification; (4) gelation; (5) atomization drying and dehydration, and finally obtains a bentonite composite mineral gel with high viscosity and high dispersibility.

[0040] Specifically, see Figure 1 The preparation method of bentonite composite mineral gel includes the following steps:

[0041] (1) Pulping: Select bentonite mineral samples, crush and screen them to form bentonite dispersion in water to form coarse slurry;

[0042] (2) Viscosity reduction and slurry preparation: Add viscosity reducer to coarse slurry, stir and mix evenly, and then slurry to obtain a highly dispersible mineral slurry with a concentration of 11-15%;

[0043] (3) Centrifugal purification: The slurry is separated by centrifugation using a dynamic centrifuge. The lower layer of slurry is taken as the purified slurry, and its solid content is 8-12%.

[0044] (4) Gelatinization activation: Add inorganic salts to increase the viscosity of the slurry. The amount of inorganic salts added is 0.5-2%.

[0045] (5) Functional group modification: Add organic ester modifier to the slurry and continue stirring. The amount of organic ester modifier added is 0.1-1%.

[0046] (6) Gelation: Add attapulgite, stir and mix evenly, and then age;

[0047] (7) Atomize and dry to obtain bentonite composite mineral gel with high viscosity and high suspension performance.

[0048] The preparation method described above, as well as the properties and structure of the prepared bentonite composite mineral gel, will be further described in detail below through specific examples.

[0049] raw material:

[0050] Attapulgite selection: Jiangsu Xuyi Shengyi Nanotechnology Co., Ltd., with a purity of 92.3%.

[0051] The bentonite was selected from Liaoning Jianping Jiaxin Mining Co., Ltd., with a purity of 91% (montmorillonite content).

[0052] Testing instruments:

[0053] Slurry ultrasonic concentration meter: DF6420, Dandong Dongfang Measurement & Control Technology Co., Ltd.

[0054] Slurry solids content analyzer: CSY-G3, Shenzhen Fenxi Instrument Manufacturing Co., Ltd.

[0055] Production equipment:

[0056] The bentonite slurry drying equipment utilizes a high-speed centrifugal spray dryer (Wuxi Angyida Machinery Co., Ltd.). Addressing the difficulties in drying high-viscosity, low-concentration bentonite slurries, it employs a combination of a large-diameter, slightly backward-inclined atomizing disc and a tower diameter of 110-130%, successfully resolving the problems of difficult atomization and severe material adhesion to the tower wall. The atomizing disc diameter is 215-280 cm, with a linear velocity of 140-180 m / s. After the high-viscosity slurry is evenly delivered to the edge of the atomizing disc under centrifugal force, the high linear velocity propels the slurry outwards, and droplets are horizontally ejected from the atomizing disc, dispersing it into a fine mist that rapidly dries the slurry at a high temperature of 100-120℃.

[0057] Example 1

[0058] (1) Select 975 grams of bentonite ore sample, crush and screen it to form bentonite dispersion in water to form a coarse slurry;

[0059] (2) Add 1% sodium hexametaphosphate to the coarse slurry, stir and mix evenly, then pound to obtain the slurry, and test the concentration of the slurry;

[0060] (3) Centrifugal purification: The slurry is separated by centrifugation using a dynamic centrifuge. The lower layer of slurry is taken as the purified slurry, and the solid content of the slurry is tested.

[0061] (4) Gelatinization activation: Add 1% sodium chloride to increase the viscosity of the slurry;

[0062] (5) Add 1% vinyltriethoxysilane to the slurry and continue stirring to carry out functional group modification, modify the organic hydrophobic group on the montmorillonite inorganic matrix, so that the montmorillonite inorganic matrix has hydrophobic properties.

[0063] (6) Gelation: Add 110 grams of attapulgite, stir and mix evenly, and age for 24 to 72 hours;

[0064] (7) At 120℃, high-speed centrifugal atomization drying and dehydration were used to obtain bentonite composite mineral gel products with high viscosity and high suspension performance.

[0065] Example 2

[0066] (1) Select 975 grams of bentonite ore sample, crush and screen it to form bentonite dispersion in water to form a coarse slurry;

[0067] (2) Add 1% sodium hexametaphosphate to the coarse slurry, stir and mix evenly, then pound to obtain the slurry, and test the concentration of the slurry;

[0068] (3) Centrifugal purification: The slurry is separated by centrifugation using a dynamic centrifuge. The lower layer of slurry is taken as the purified slurry, and the solid content of the slurry is tested.

[0069] (4) Gelatinization activation: Add 2% sodium chloride to increase the viscosity of the slurry;

[0070] (5) Add 1% vinyltriethoxysilane to the slurry and continue stirring to carry out functional group modification, modify the organic hydrophobic group on the montmorillonite inorganic matrix, so that the montmorillonite inorganic matrix has hydrophobic properties.

[0071] (6) Gelation: Add 110 grams of attapulgite, stir and mix evenly, and age for 24 to 72 hours;

[0072] (7) At 100℃, high-speed centrifugal atomization drying and dehydration were used to obtain bentonite composite mineral gel products with high viscosity and high suspension performance.

[0073] Example 3

[0074] (1) Select 975 grams of bentonite ore sample, crush and screen it to form bentonite dispersion in water to form a coarse slurry;

[0075] (2) Add 1% sodium hexametaphosphate to the coarse slurry, stir and mix evenly, then pound to obtain the slurry, and test the concentration of the slurry;

[0076] (3) Centrifugal purification: The slurry is separated by centrifugation using a dynamic centrifuge. The lower layer of slurry is taken as the purified slurry, and the solid content of the slurry is tested.

[0077] (4) Gelation activation: Add 2% magnesium sulfate to increase the viscosity of the slurry;

[0078] (5) Add 1% vinyltriethoxysilane to the slurry and continue stirring to carry out functional group modification, modify the organic hydrophobic group on the montmorillonite inorganic matrix, so that the montmorillonite inorganic matrix has hydrophobic properties.

[0079] (6) Gelation: Add 110 grams of attapulgite, stir and mix evenly, and age for 24 to 72 hours;

[0080] (7) At 100℃, high-speed centrifugal atomization drying and dehydration were used to obtain bentonite composite mineral gel products with high viscosity and high suspension performance.

[0081] Example 4

[0082] (1) Select 975 grams of bentonite ore sample, crush and screen it to form bentonite dispersion in water to form a coarse slurry;

[0083] (2) Add 1% sodium hexametaphosphate to the coarse slurry, stir and mix evenly, then pound to obtain the slurry, and test the concentration of the slurry;

[0084] (3) Centrifugal purification: The slurry is separated by centrifugation using a dynamic centrifuge. The lower layer of slurry is taken as the purified slurry, and the solid content of the slurry is tested.

[0085] (4) Gelation activation: Add 0.5% aluminum chloride to increase the viscosity of the slurry;

[0086] (5) Add 0.1% vinyltriethoxysilane to the slurry and continue stirring to carry out functional group modification, modify the organic hydrophobic group on the montmorillonite inorganic matrix, so that the montmorillonite inorganic matrix has hydrophobic properties.

[0087] (6) Gelation: Add 110 grams of attapulgite, stir and mix evenly, and age for 24 to 72 hours;

[0088] (7) At 100℃, high-speed centrifugal atomization drying and dehydration were used to obtain bentonite composite mineral gel products with high viscosity and high suspension performance.

[0089] Example 5

[0090] (1) Select 975 grams of bentonite ore sample, crush and screen it to form bentonite dispersion in water to form a coarse slurry;

[0091] (2) Add 2% sodium pyrophosphate to the coarse slurry, stir and mix evenly, then pound to obtain the slurry, and test the concentration of the slurry;

[0092] (3) Centrifugal purification: The slurry is separated by centrifugation using a dynamic centrifuge. The lower layer of slurry is taken as the purified slurry, and the solid content of the slurry is tested.

[0093] (4) Gelation activation: Add 1% aluminum sulfate to increase the viscosity of the slurry;

[0094] (5) Add 0.5% aminosilane to the slurry and continue stirring to carry out functional group modification, modify the montmorillonite inorganic matrix with organic hydrophobic groups, so that the montmorillonite inorganic matrix has hydrophobic properties.

[0095] (6) Gelation: Add 110 grams of attapulgite, stir and mix evenly, and age for 24 to 72 hours;

[0096] (7) At 100℃, high-speed centrifugal atomization drying and dehydration were used to obtain bentonite composite mineral gel products with high viscosity and high suspension performance.

[0097] Example 6

[0098] (1) Select 975 grams of bentonite ore sample, crush and screen it to form bentonite dispersion in water to form a coarse slurry;

[0099] (2) Add 2.5% sodium pyrophosphate to the coarse slurry, stir and mix evenly, then pound to obtain the slurry, and test the concentration of the slurry;

[0100] (3) Centrifugal purification: The slurry is separated by centrifugation using a dynamic centrifuge. The lower layer of slurry is taken as the purified slurry, and the solid content of the slurry is tested.

[0101] (4) Gelatinization activation: Add 2% aluminum chloride to increase the viscosity of the slurry;

[0102] (5) Add 1% methacryloyloxysilane to the slurry and continue stirring to carry out functional group modification, modify the montmorillonite inorganic matrix with organic hydrophobic groups, so that the montmorillonite inorganic matrix has hydrophobic properties.

[0103] (6) Gelation: Add 110 grams of attapulgite, stir and mix evenly, and age for 24 to 72 hours;

[0104] (7) At 100℃, high-speed centrifugal atomization drying and dehydration were used to obtain bentonite composite mineral gel products with high viscosity and high suspension performance.

[0105] Example 7

[0106] (1) Select 975 grams of bentonite ore sample, crush and screen it to form bentonite dispersion in water to form a coarse slurry;

[0107] (2) Add 3% sodium pyrophosphate to the coarse slurry, stir and mix evenly, then pound to obtain the slurry, and test the concentration of the slurry;

[0108] (3) Centrifugal purification: The slurry is separated by centrifugation using a dynamic centrifuge. The lower layer of slurry is taken as the purified slurry, and the solid content of the slurry is tested.

[0109] (4) Gelatinization activation: Add 2% aluminum chloride to increase the viscosity of the slurry;

[0110] (5) Add 3% methacryloyloxysilane to the slurry and continue stirring to carry out functional group modification, modify the montmorillonite inorganic matrix with organic hydrophobic groups, so that the montmorillonite inorganic matrix has hydrophobic properties.

[0111] (6) Gelation: Add 110 grams of attapulgite, stir and mix evenly, and age for 24 to 72 hours;

[0112] (7) At 100℃, high-speed centrifugal atomization drying and dehydration were used to obtain bentonite composite mineral gel products with high viscosity and high suspension performance.

[0113] Example 7

[0114] (1) Select 975 grams of bentonite ore sample, crush and screen it to form bentonite dispersion in water to form a coarse slurry;

[0115] (2) Add 1% sodium pyrophosphate to the coarse slurry, stir and mix evenly, then pound to obtain the slurry, and test the concentration of the slurry;

[0116] (3) Centrifugal purification: The slurry is separated by centrifugation using a dynamic centrifuge. The lower layer of slurry is taken as the purified slurry, and the solid content of the slurry is tested.

[0117] (4) Gelatinization activation: Add 2% aluminum chloride to increase the viscosity of the slurry;

[0118] (5) Add 3% methacryloyloxysilane to the slurry and continue stirring to carry out functional group modification, modify the montmorillonite inorganic matrix with organic hydrophobic groups, so that the montmorillonite inorganic matrix has hydrophobic properties.

[0119] (6) Gelation: Add 110 grams of attapulgite, stir and mix evenly, and age for 24 to 72 hours;

[0120] (7) At 100℃, high-speed centrifugal atomization drying and dehydration were used to obtain bentonite composite mineral gel products with high viscosity and high suspension performance.

[0121] Example 9

[0122] (1) 824 grams of bentonite ore sample was selected, crushed and sieved to form bentonite dispersion in water to form a coarse slurry;

[0123] (2) Add 2.5% sodium pyrophosphate to the coarse slurry, stir and mix evenly, then pound to obtain the slurry, and test the concentration of the slurry;

[0124] (3) Centrifugal purification: The slurry is separated by centrifugation using a dynamic centrifuge. The lower layer of slurry is taken as the purified slurry, and the solid content of the slurry is tested.

[0125] (4) Gelation activation: Add 1.5% aluminum chloride to increase the viscosity of the slurry;

[0126] (5) Add 0.8% methacryloyloxysilane to the slurry and continue stirring to carry out functional group modification, modify the montmorillonite inorganic matrix with organic hydrophobic groups, so that the montmorillonite inorganic matrix has hydrophobic properties.

[0127] (6) Gelation: Add 271 g of attapulgite, stir and mix evenly, and age for 24-72 hours;

[0128] (7) At 100℃, high-speed centrifugal atomization drying and dehydration were used to obtain bentonite composite mineral gel products with high viscosity and high suspension performance.

[0129] Example 10

[0130] (1) 879 grams of bentonite ore sample was selected, crushed and screened to form bentonite dispersion in water to form a coarse slurry;

[0131] (2) Add 2.5% sodium pyrophosphate to the coarse slurry, stir and mix evenly, then pound to obtain the slurry, and test the concentration of the slurry;

[0132] (3) Centrifugal purification: The slurry is separated by centrifugation using a dynamic centrifuge. The lower layer of slurry is taken as the purified slurry, and the solid content of the slurry is tested.

[0133] (4) Gelation activation: Add 1.5% aluminum chloride to increase the viscosity of the slurry;

[0134] (5) Add 0.8% methacryloyloxysilane to the slurry and continue stirring to carry out functional group modification, modify the montmorillonite inorganic matrix with organic hydrophobic groups, so that the montmorillonite inorganic matrix has hydrophobic properties.

[0135] (6) Gelation: Add 217 g of attapulgite, stir and mix evenly, and age for 24-72 hours;

[0136] (7) At 100℃, high-speed centrifugal atomization drying and dehydration were used to obtain bentonite composite mineral gel products with high viscosity and high suspension performance.

[0137] Example 11

[0138] (1) Select 999 grams of bentonite ore sample, crush and screen it to form bentonite dispersion in water to form a coarse slurry;

[0139] (2) Add 2.5% sodium pyrophosphate to the coarse slurry, stir and mix evenly, then pound to obtain the slurry, and test the concentration of the slurry;

[0140] (3) Centrifugal purification: The slurry is separated by centrifugation using a dynamic centrifuge. The lower layer of slurry is taken as the purified slurry, and the solid content of the slurry is tested.

[0141] (4) Gelation activation: Add 1.5% aluminum chloride to increase the viscosity of the slurry;

[0142] (5) Add 0.8% methacryloyloxysilane to the slurry and continue stirring to carry out functional group modification, modify the montmorillonite inorganic matrix with organic hydrophobic groups, so that the montmorillonite inorganic matrix has hydrophobic properties.

[0143] (6) Gelation: Add 98.5 g of attapulgite, stir and mix evenly, and age for 24-72 hours;

[0144] (7) At 100℃, high-speed centrifugal atomization drying and dehydration were used to obtain bentonite composite mineral gel products with high viscosity and high suspension performance.

[0145] Example 12

[0146] (1) 1014 grams of bentonite ore sample was selected, crushed and sieved to form bentonite dispersion in water to form a coarse slurry;

[0147] (2) Add 2.5% sodium pyrophosphate to the coarse slurry, stir and mix evenly, then pound to obtain the slurry, and test the concentration of the slurry;

[0148] (3) Centrifugal purification: The slurry is separated by centrifugation using a dynamic centrifuge. The lower layer of slurry is taken as the purified slurry, and the solid content of the slurry is tested.

[0149] (4) Gelation activation: Add 1.5% aluminum chloride to increase the viscosity of the slurry;

[0150] (5) Add 0.8% methacryloyloxysilane to the slurry and continue stirring to carry out functional group modification, modify the montmorillonite inorganic matrix with organic hydrophobic groups, so that the montmorillonite inorganic matrix has hydrophobic properties.

[0151] (6) Gelation: Add 83 grams of attapulgite, stir and mix evenly, and age for 24 to 72 hours;

[0152] (7) At 100℃, high-speed centrifugal atomization drying and dehydration were used to obtain bentonite composite mineral gel products with high viscosity and high suspension performance.

[0153] The bentonite composite mineral gel prepared by the above method is a binary mineral gel composed of montmorillonite and attapulgite, with bentonite as the main component and attapulgite as the auxiliary component. In Examples 1-8, the mass ratio of montmorillonite to attapulgite is 9:1; in Example 9, the mass ratio of montmorillonite to attapulgite is 3:1; in Example 10, the mass ratio of montmorillonite to attapulgite is 4:1; in Example 11, the mass ratio of montmorillonite to attapulgite is 10:1; and in Example 12, the mass ratio of montmorillonite to attapulgite is 12:1.

[0154] Product testing methods:

[0155] Viscosity determination of the 5% dispersion system: Weigh 13.0g of the product prepared in the example, disperse it in 247.0g of distilled aqueous solution to prepare a dispersion with a 5% solid content; transfer it to a high-angle beaker, seal it at 20°C, let it stand for 24 hours, and then measure its viscosity (NDJ-8S viscometer, #4 rotor, 6 and 60 rpm).

[0156] Suspension evaluation of the 1% dispersion system: Weigh 1.5g of inorganic gel and disperse it in 148.5g of distilled aqueous solution; stir at 2000 rpm for 30 minutes to form a dispersion with a 1% solid content; then, transfer a certain amount of the dispersion to a 100mL graduated cylinder (to the maximum mark) and let it stand for 24 hours. Observe whether there is any layering or water precipitation in the graduated cylinder.

[0157] Dispersion performance test: Add 146.25g of water to a 250mL beaker, weigh 3.75g of dried sample and add it to the beaker, place it on a magnetic stirrer to start dispersion, and start timing with a stopwatch. Observe the dispersion of the material in the inorganic gel aqueous dispersion until the material is completely dispersed in water, and record the time taken with the stopwatch, which is the dispersion time.

[0158] The bentonite composite mineral gel products prepared in Examples 1-12 were tested for viscosity, dispersion performance and suspension performance according to the above method. The test results are shown in Table 1.

[0159] As can be seen from Table 1 above, the production and purification of bentonite slurry using the present invention yields a highly dispersible slurry concentration of 11-15% and a solid content of 8-12% after purification.

[0160] By comparing Examples 1-3 with Examples 4-8, it was found that sodium, magnesium, and aluminum inorganic salts were selected to activate the cementitious properties of the inorganic matrix of the slurry, with aluminum ions showing the best effect.

[0161] Examples 1-12, using different montmorillonite to attapulgite ratios and the same method, exhibited significant differences in viscosity and dispersion properties. As the montmorillonite to attapulgite ratio increased, the viscosity gradually rose, reaching its maximum at a ratio of 9:1, after which it decreased. Specifically, Examples 1-8, using a montmorillonite to attapulgite ratio of 9:1, demonstrated significantly superior viscosity and dispersion properties. In contrast, Examples 9-12 used montmorillonite to attapulgite ratios of 3:1, 4:1, 10:1, and 12:1, respectively. Example 9 showed better dispersion properties, but its viscosity decreased significantly. Example 13 had a better viscosity value, but poorer dispersion properties, and both examples showed precipitation in suspension tests, indicating that their suspension performance did not meet requirements.

[0162] The bentonite-based composite mineral gel prepared by this invention exhibits excellent dispersibility, suspension properties, and high viscosity, showing broad application prospects, primarily in the pesticide and coating industries. Examples are provided below.

[0163] Table 1. Test results of slurry concentration, solid content, and product performance in Examples 1-12.

[0164]

[0165] Example 13

[0166] In the application of pesticides, this embodiment uses the bentonite composite mineral gel prepared in Example 5, and conducts a comparative test on its suspension and viscosity properties with Hemings Deqian organic modified bentonite (model: Bentone LT, hereinafter referred to as LT bentonite) and organic modified bentonite (model: TY-166C, Guangying New Materials (Guangzhou) Co., Ltd., hereinafter referred to as TY bentonite).

[0167] Test method:

[0168] Automatic dispersion performance test: 99.5 mL of standard hard water is placed in a 100 mL stoppered conical graduated cylinder. 0.5 mL of the sample to be tested is taken using a syringe and dropped into the water from a distance of 5 cm from the water surface. The dispersion is observed. Grades are categorized as excellent, good, and poor.

[0169] Advantages: It disperses automatically in water in a cloud-like manner;

[0170] Good: It can disperse automatically in water, with some particles settling down, and disperses again after slight stirring;

[0171] Disadvantages: It cannot disperse automatically in water, and sinks as particles to flocculent particles, requiring vigorous shaking to disperse.

[0172] The dispersion time test method is the same as above. The dispersion state after being poured into water is then visually assessed.

[0173] Suspension rate (%) determination:

[0174] Weigh 1g of suspension into a 259mL graduated cylinder, dilute with 342ppm standard hard water, shake, and let stand in a 30℃ constant temperature water bath for 1 hour. Take the upper 225mL of suspension, transfer the remaining suspension to a small beaker with distilled water, dry (80℃), dissolve in methanol, and dilute to a 10mL volumetric flask for liquid chromatography analysis.

[0175] Stability: Visually assessed.

[0176] The three product groups were dispersed separately in 52% thiram solution. Thiram, or tetramethylthiram disulfide, is a broad-spectrum fungicide mainly used for seed and soil treatment to prevent damping-off and other diseases in various crops such as corn, cotton, cereals, and vegetables. The test results are shown in Table 2.

[0177] Table 2 Performance Comparison with Existing Technology Products Applied to Thiram Water

[0178]

[0179] As shown in Table 2, the product prepared by this invention has extremely high viscosity. Even after being stored at 50°C for 5 days, the viscosity still has a significant advantage. Other properties are comparable to those of LT bentonite. Obviously, it has superior performance compared to similar products with excellent performance currently on the market.

[0180] Example 14

[0181] It is used as an environmentally friendly thickening and suspending agent in water-based coatings.

[0182] This invention relates to an inorganic mineral gel based on bentonite, which possesses excellent non-toxic and environmentally friendly properties. Therefore, its application as an environmentally friendly additive in the coatings industry has extremely broad prospects.

[0183] In this embodiment, Example 5, LT bentonite and DE bentonite (Hemings Deqian organic modified bentonite, model: Bentone DE, lithium montmorillonite organic bentonite), and Haidis C919 (Zhejiang Hangzhou Haidis New Materials Co., Ltd.) were selected for comparative tests on parameters and performance. The results are shown in Table 3.

[0184] Table 3. Performance Comparison of the Invention and Existing Technology Products in Waterborne Coatings

[0185]

[0186] As shown in Table 3, when the above products are used as thickeners and suspending agents, the water resistance and salt spray resistance of the water-based paint film all decrease. Haimings' LT bentonite and DE bentonite also cause a significant decrease in the water resistance of the paint film, and their salt spray resistance is also significantly affected. However, the high-performance environmentally friendly inorganic mineral cementing material used in this project has the least impact on the water resistance and salt spray resistance of the paint film. The order of side effects of different additives is: LT bentonite > DE bentonite > C919 > Example 5. The high-performance environmentally friendly inorganic mineral cementing material performs best among the above-mentioned similar products in water-based paints, exhibiting good compatibility and minimal impact on paint film performance, which is beneficial for preventing sedimentation and sagging.

[0187] In summary, the bentonite composite mineral gel prepared by this invention has superior overall performance in pesticides and coatings compared to products in the prior art.

[0188] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing a bentonite composite mineral gel, characterized in that, Includes the following steps: (1) Pulping, viscosity reduction and purification; (2) Gelatinization activation; (3) Functional group modification; (4) Gelation; (5) Atomization drying and dehydration, finally obtaining bentonite composite mineral gel with high viscosity and high dispersibility; Specifically, it includes the following steps: (1) Pulping: Bentonite is dispersed in water to form a coarse slurry; (2) Viscosity reduction and slurry preparation: Add viscosity reducer to coarse slurry, stir and mix evenly, and then slurry to obtain a highly dispersible mineral slurry with a concentration of 11~15%; (3) Centrifugal purification: The slurry is separated by centrifugation using a dynamic centrifuge. The lower layer of slurry is the purified slurry, and its solid content is 8-12%. (4) Gelatinization activation: Add inorganic salts to increase the viscosity of the slurry. The amount of inorganic salts added is 0.5-2%. (5) Functional group modification: Organic ester modifiers are added to the slurry to improve the hydrophobic properties of the inorganic montmorillonite matrix. The amount of organic ester modifier added is 0.1-1%. (6) Gelation: Add attapulgite, stir and mix evenly, and then age; (7) Atomized drying and dehydration to obtain bentonite composite mineral gel with high viscosity and high suspension performance; The mass ratio of montmorillonite to attapulgite is 4:1 to 10:

1. The organic ester modifier mentioned in step (5) is an organic ester hydrophobic modifier, which forms an inorganic matrix bonding layer with montmorillonite to obtain an organic matrix-organic ester modifier-inorganic matrix bonding layer, thereby improving the hydrophobic properties of the inorganic matrix; The organic ester modifier is an organosilicon or titanate coupling agent; The atomizing equipment used in step (6) includes an atomizing disc with a diameter of 215~280cm and a linear velocity of 140~180m / s. The high-speed rotation disperses the high-viscosity slurry into a mist.

2. The preparation method of the bentonite composite mineral gel as described in claim 1, characterized in that, The viscosity reducer mentioned in step (2) is either sodium hexametaphosphate or sodium pyrophosphate.

3. The method for preparing bentonite composite mineral gel as described in claim 1, characterized in that, The inorganic salt in step (4) is Na. + Mg 2+ Al 3+ Ca 2+ K + An inorganic salt of at least one metal ion.

4. A bentonite composite mineral gel prepared by the method according to any one of claims 1-3, characterized in that, The bentonite composite mineral gel is a binary mineral gel composed of bentonite as the main component and attapulgite as the auxiliary component, which is montmorillonite-attapulgite composite. The mass ratio of montmorillonite to attapulgite is 4:1 to 10:

1. The attapulgite molecules are dispersed in the gaps between the montmorillonite molecules, and the montmorillonite and attapulgite molecules are stacked to form a rod-plate tower structure.

5. The bentonite composite mineral gel as described in claim 4, characterized in that, The bentonite composite mineral gel has a viscosity ≥2200MPa·s and a dispersion time of 5~7min.

6. An application of the bentonite composite mineral gel as described in any one of claims 4-5, characterized in that, The bentonite composite mineral gel is used as a thickening and suspending agent in pesticides and water-based coatings.

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