A stable suspension of bentonite thickening gel and a method for preparing the same

Abstract

The present application relates to the technical field of gel preparation, and particularly relates to a stable suspension bentonite thickening gel preparation method, bentonite is wet-milled for pretreatment to obtain pretreatment slurry, the pretreatment slurry is placed in a reaction kettle, and the pretreatment slurry is subjected to layered detection, whether the pretreatment slurry meets the reaction requirement of an organic modifier is determined based on the wet-milling characteristic value, in response to the pretreatment slurry meeting the reaction requirement of the organic modifier, nitrogen gas of a preset flow is introduced into the reaction kettle, and the pretreatment slurry is subjected to heating treatment; whether the intercalation reaction of the organic modifier is sufficient is determined according to the viscosity change rate and the conductivity change rate of the organic modifier intercalation in each layer of the pretreatment slurry, and a polyvalent ion crosslinking agent is added into the modified slurry generated after the intercalation reaction of the organic modifier is sufficient to prepare bentonite gel. The present application improves the stability of the stable suspension bentonite thickening gel preparation method.

Description

Technical Field

[0001] This invention relates to the field of gel preparation technology, and in particular to a stable suspended bentonite thickened gel and its preparation method. Background Technology

[0002] Bentonite is widely used in daily chemical and composite materials fields. Organic bentonite prepared by intercalating organic modifiers into the bentonite interlayer can effectively improve its dispersibility and compatibility in organic systems. It is a key raw material for preparing high-performance composite materials, coatings, gels and adsorbents. During the wet milling process, the uniformity of the particle size distribution of bentonite and the stratification stability of the slurry directly affect the efficiency and uniformity of the subsequent organic modifier intercalation reaction. At the same time, effective online monitoring indicators should be established for the dynamic process, reaction rate and completion of the intercalation diffusion of the modifier in different interlayer domains of bentonite to ensure that the adsorption force of each layer can keep the bentonite stably suspended. This invention aims to achieve precise and controllable preparation of high-performance, high-stability bentonite gels by introducing a series of key technologies such as wet milling characteristic evaluation, dynamic determination and temperature optimization of intercalation reaction, and prediction of gel stability.

[0003] Chinese Patent Application Publication No. CN115703056A discloses a method for preparing bentonite composite mineral gel, comprising the following steps: (1) slurry preparation, viscosity reduction and purification; (2) gelling activation; (3) functional group modification; (4) gelation; (5) atomization drying and dehydration, ultimately obtaining a bentonite composite mineral gel with high viscosity and high dispersibility. This invention employs a "suppression followed by enhancement" technical approach, first reducing viscosity to increase the concentration of the slurry, then adding an activator to 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 the final bentonite-montmorillonite composite inorganic mineral gel possessing extremely strong hydrophobic properties, thus exhibiting high viscosity and high dispersibility. This invention can be used as a thickening and suspending agent in water-based coatings and pesticides.

[0004] The existing technology also has the following problems: the existing technology does not take into account the introduction of inert gas after adding organic modifiers to reduce the impact of high temperature environment on slurry reaction, and does not set corresponding standards for different adjustment steps to judge the suspension performance of thickened gel. Summary of the Invention

[0005] Therefore, the present invention provides a method for preparing a stable suspended bentonite thickening gel, which overcomes the problem in the prior art that does not take into account the introduction of inert gas after adding organic modifiers to reduce the influence of high temperature environment on slurry reaction, and sets corresponding standards for different adjustment steps to judge the suspension performance of thickening gel.

[0006] To achieve the above objectives, the present invention provides a method for preparing a stable suspended bentonite thickening gel, comprising: Bentonite is pretreated by wet milling to obtain a pretreated slurry, which is then placed in a reaction vessel. The pretreated slurry is subjected to stratified detection. Based on the vibration frequency and particle size distribution width of each layer of pretreated slurry, wet milling characteristic values ​​are generated to determine whether the pretreated slurry meets the reaction requirements of the organic modifier. In response to the pretreated slurry not meeting the reaction requirements of the organic modifier, a wet grinding deviation value is calculated based on the wet grinding characteristic value and the wet grinding characteristic threshold. Based on the comparison result of the wet grinding deviation value and the preset wet grinding deviation threshold, an interlayer stripping aid is added to the reactor or the stirring power and stirring time of the reactor are adjusted. In response to the pretreated slurry meeting the reaction requirements of the organic modifier, nitrogen gas of a preset flow rate is introduced into the reactor to heat the pretreated slurry. The intercalation reaction of the organic modifier is determined based on the viscosity change rate and conductivity change rate of the organic modifier in each layer of pretreated slurry. If the intercalation reaction of the organic modifier is insufficient, an optimized temperature value is determined based on the viscosity difference of the organic modifier in each layer of pretreated slurry and the preset flow rate of nitrogen to ensure that the intercalation reaction of the organic modifier is sufficient. In response to the complete intercalation reaction of the organic modifier, a multivalent ionic crosslinking agent is added to the modified slurry generated after the complete intercalation reaction of the organic modifier to prepare bentonite gel; The stability of the suspension capacity of bentonite gel is determined based on the decrease in conductivity of the modified slurry or the variable curve of viscosity of the modified slurry with temperature optimization. If the suspension capacity of bentonite gel is unstable, the standard of suspension capacity of bentonite gel is determined based on real-time monitoring of pH value of modified slurry. The resonant frequency is determined by the ratio of the mean vibration frequency of each layer of pretreatment slurry to the reference vibration frequency. The ratio of the mean particle size distribution width of each layer of pretreated slurry to the reference particle size distribution width is determined as the particle size factor. The weighted sum of the resonance frequency and the particle size factor is determined to be the wet grinding characteristic value.

[0007] Furthermore, based on the wet milling characteristic values, it is determined whether the pretreated slurry meets the reaction requirements of the organic modifier, wherein... The resonant frequency is determined by the ratio of the mean vibration frequency of each layer of pretreatment slurry to the reference vibration frequency. The ratio of the mean particle size distribution width of each layer of pretreated slurry to the reference particle size distribution width is determined as the particle size factor. The weighted sum of the resonant frequency and the particle size factor is determined to be the wet milling characteristic value; If the wet milling characteristic value is less than or equal to the wet milling characteristic threshold, then the pretreated slurry is determined to meet the reaction requirements of the organic modifier. If the wet milling characteristic value is greater than the wet milling characteristic threshold, it is determined that the pretreated slurry does not meet the reaction requirements of the organic modifier.

[0008] Furthermore, the process of adding an interlayer stripping agent to the reactor or adjusting the stirring power and stirring time of the reactor based on the comparison result of the wet grinding deviation value and the preset wet grinding deviation threshold includes, The difference between the wet grinding characteristic value and the wet grinding characteristic threshold is calculated as the wet grinding deviation value; If the wet grinding deviation value is less than or equal to the first wet grinding deviation threshold, it is determined that the stirring power and stirring time of the reactor should be adjusted. If the wet grinding deviation value is greater than the first wet grinding deviation threshold and less than or equal to the second wet grinding deviation threshold, it is determined that an interlayer stripping agent is added to the reactor at a first preset ratio. If the wet grinding deviation value is greater than the second wet grinding deviation threshold, it is determined that an interlayer stripping agent is added to the reactor at a second preset ratio.

[0009] Furthermore, the process of calculating the correlation index based on the viscosity and conductivity change rates of the organic modifier intercalation in each layer of the pretreatment slurry includes the following steps: Collect several viscosity values ​​and several conductivity values ​​within a preset time period; Calculate the viscosity change rate of adjacent viscosity values ​​within a preset time period to generate a viscosity change dataset; Calculate the rate of change of conductivity between adjacent conductivity values ​​within a preset time period to generate a conductivity change dataset; The correlation between the viscosity change dataset and the conductivity change dataset is calculated based on the Pearson correlation coefficient formula to generate a correlation index.

[0010] Furthermore, the sufficiency of the intercalation reaction of the organic modifier is determined based on the change-related index, among which, Under the condition that no interlayer stripping agent is added to the reactor and the stirring power and stirring time of the reactor are not adjusted, if the change correlation index is greater than or equal to the first change correlation index threshold, the intercalation reaction of the organic modifier is determined to be sufficient; if the change correlation index is less than the first change correlation index threshold, the intercalation reaction of the organic modifier is determined to be insufficient. Under the condition that interlayer stripping agent is added to the reactor at a first preset ratio, if the change correlation index is greater than or equal to the second change correlation index threshold, the intercalation reaction of the organic modifier is determined to be sufficient; if the change correlation index is less than the second change correlation index threshold, the intercalation reaction of the organic modifier is determined to be insufficient. Under the condition that an interlayer stripping agent is added to the reactor at a second preset ratio or the stirring power and stirring time of the reactor are adjusted, if the change correlation index is greater than or equal to the third change correlation index threshold, the intercalation reaction of the organic modifier is determined to be sufficient; if the change correlation index is less than the third change correlation index threshold, the intercalation reaction of the organic modifier is determined to be insufficient.

[0011] Furthermore, the process of determining the optimal temperature value based on the viscosity difference of the organic modifier intercalation in each layer of the pretreated slurry and the preset flow rate of nitrogen includes the following steps: The upper temperature limit is determined based on the preset flow rate; Calculate the average viscosity difference of the pretreatment slurry in adjacent layers to determine the required temperature value; If the required temperature value is less than the upper limit temperature value, then the optimized temperature value is determined to be the required temperature value. If the required temperature value is greater than or equal to the upper limit temperature value, then the optimized temperature value is determined to be the upper limit temperature value.

[0012] Furthermore, the process of determining whether the suspension capacity of bentonite gel is stable based on the decrease in conductivity of the modified slurry or the viscosity of the modified slurry as a function of temperature optimization includes the following steps: If the temperature optimization treatment was not performed before the modified slurry was generated, the conductivity values ​​were sorted according to the preset time, and the conductivity value at the end of the sort was selected as the organic conductivity value. The conductivity value at which the conductivity stabilized again after the addition of the multivalent ion crosslinking agent was determined as the crosslinking conductivity value. The difference between the organic conductivity value and the crosslinking conductivity value was calculated as the conductivity decrease. If temperature optimization is performed before the modified slurry is generated, the slope of the variable curve is obtained.

[0013] Furthermore, the stability of the suspension capacity of the bentonite gel is determined based on the decrease in the conductivity of the modified slurry or the viscosity variation curve of the modified slurry with temperature optimization. If the decrease in conductivity is greater than the threshold for the decrease in conductivity or the slope of the variable curve is within the allowable fluctuation range, then the suspension capacity of the bentonite gel is determined to be stable. If the decrease in conductivity is not greater than the threshold value of the decrease in conductivity or the slope of the variable curve is not within the allowable fluctuation range, then the suspension capacity of the bentonite gel is determined based on the real-time monitoring of the pH value of the modified slurry.

[0014] Furthermore, the process of determining whether the suspension capacity of the bentonite gel meets the standard based on real-time monitoring of the pH value of the modified slurry includes: The pH value of the modified slurry is monitored in real time to plot the pH fluctuation curve; The predicted addition rate of the multivalent ion crosslinking agent is determined based on the pH fluctuation curve. The suspension capacity of the bentonite gel is determined based on the rate difference between the predicted addition rate and the actual addition rate. If the rate difference is less than the rate difference threshold, the suspension capacity of the bentonite gel is determined to meet the standard.

[0015] The present invention also provides a bentonite thickening gel, comprising: 10-15 parts bentonite, 5-10 parts organic modifier, 1-2 parts polyvalent ion crosslinking agent, 2-6 parts rheology modifier, 1-4 parts surfactant stabilizer, 1-2 parts nitrogen, and 1-2 parts interlayer stripping agent.

[0016] Compared with the prior art, the beneficial effects of the present invention are that it constructs a comprehensive wet milling characteristic value by detecting the vibration frequency and particle size distribution width after the slurry stratifies. This value can quantitatively reflect the degree of dissociation of bentonite particles, particle size uniformity, and slurry structure stability after wet milling, providing an objective and quantifiable standard for judging the pretreatment effect. By placing the pretreated slurry in the reaction vessel and immediately performing stratification detection and calculating the characteristic value, it is possible to determine in real time whether it has met the requirements of the subsequent organic modification reaction for the state of the base material, thereby further improving the stability of the method for preparing stable suspended bentonite thickening gel.

[0017] Furthermore, this invention, by taking corrective measures when the pretreated slurry does not meet the reaction requirements of the organic modifier, and calculating the wet grinding deviation value, determines whether to add an interlayer stripping aid to the pretreated slurry for chemically assisted dissociation or adjust the stirring power and time to enhance physical shearing by comparing the wet grinding deviation value with a threshold. This achieves precise input of energy and chemicals. When the pretreated slurry meets the requirements, the core purpose of introducing nitrogen at a preset flow rate is to replace the air in the reactor before heating, creating an inert environment. This effectively prevents the exchangeable cations between bentonite layers and the subsequently added organic modifier from being oxidized during heating. The preset flow rate and subsequent heating treatment together ensure that the initial physicochemical environment is strictly consistent and controlled when each qualified material enters the modification reaction stage. This response achieves a seamless transition from pretreatment quality inspection to modification reaction initiation, improving the continuity of the production process, thereby further improving the stability of the method for preparing stable suspended bentonite thickening gel.

[0018] Furthermore, by simultaneously monitoring two key physical parameters—viscosity change rate and conductivity change rate—this invention can dynamically reveal the essence of the reaction from different dimensions. Viscosity change rate directly reflects changes in the system's microstructure. The insertion of organic modifiers into the bentonite interlayers increases the interlamellar spacing and alters the hydrodynamic interactions between particles, typically leading to significant and regular changes in system viscosity. Monitoring its change rate can reflect the structural reconstruction kinetics induced by the intercalation reaction in real time. Conductivity change rate can sensitively capture changes in the ionic environment. Intercalation reactions are often accompanied by cation exchange and changes in the concentration of free ions in the system. Conductivity change rate can monitor the progress of this electrochemical process in real time. Under conditions indicating incomplete reaction, the viscosity difference reflects the distribution of mass transfer resistance within the reaction system. Under normal circumstances, the large differences in viscosity among the layers indicate that the diffusion and intercalation processes of the organic modifier in the slurry are inconsistent. Increasing the temperature is an effective physical means to reduce the viscosity of the system and promote diffusion mass transfer. The preset nitrogen flow rate, as a previously set protective process parameter, is related to the heat transfer efficiency of the reaction environment and the risk of local hot spots. The flow rate affects the flow state of the atmosphere inside the reactor, thus affecting heat exchange. By combining the above two key parameters to calculate the optimized temperature value, it can be ensured that each batch of intercalation reaction truly reaches a sufficient and complete state, avoiding problems such as organic modifier residue and insufficient interlayer exchange rate caused by incomplete reaction. This ensures that the organic bentonite base material has optimal compatibility and interlayer spacing, thereby further improving the stability of the preparation method of stable suspended bentonite thickening gel.

[0019] Furthermore, this invention, through the addition of a multivalent ionic crosslinking agent, enables ionic crosslinking with negatively charged bentonite sheets, simultaneously fixing or consuming free ions in the system, leading to a significant decrease in conductivity. The magnitude and rate of this conductivity decrease directly quantify the degree and speed of the crosslinking reaction. Meanwhile, the viscosity of the gel is extremely sensitive to temperature; analyzing the variation curve allows for the assessment of the thermal stability, structural strength, and thixotropy of the gel network. Using different judgment criteria for modified slurries obtained through different control methods improves the accuracy of determining the suspension capacity of the bentonite gel. Simultaneously, pH profoundly affects the surface charge of the bentonite sheets, the state of the organic modifier, and the crosslinking behavior of multivalent ions. Real-time control of the pH of the reaction system within the optimal window is crucial to ensuring the crosslinking reaction proceeds along the predetermined path. Under conditions where the suspension capacity of the bentonite gel is deemed unstable, verifying whether the suspension capacity meets the standard based on pH fluctuations avoids resource waste caused by overly stringent judgment criteria, thereby further improving the stability of the method for preparing stable suspended bentonite thickening gels. Attached Figure Description

[0020] Figure 1 This is a flowchart illustrating the steps of a method for preparing a stable suspended bentonite thickening gel according to an embodiment of the present invention. Figure 2 This is a logic diagram for determining whether the pretreated slurry meets the reaction requirements of the organic modifier in an embodiment of the present invention. Figure 3 This is a logic diagram for adding interlayer stripping aids or adjusting the stirring power and stirring time of the reactor based on the comparison result of the wet grinding deviation value and the preset wet grinding deviation threshold in an embodiment of the present invention. Figure 4 This is a logic diagram for determining whether the suspension capacity of bentonite gel meets the standard in an embodiment of the present invention. Detailed Implementation

[0021] To make the objectives and advantages of the present invention clearer, the present invention will be further described below with reference to embodiments; it should be understood that the specific embodiments described herein are merely for explaining the present invention and are not intended to limit the present invention.

[0022] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0023] It should be noted that, in the description of this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0024] Please see Figure 1 The diagram shown is an overall structural block diagram of the method for preparing a stable suspended bentonite thickening gel according to an embodiment of the present invention. The method for preparing a stable suspended bentonite thickening gel according to an embodiment of the present invention includes: Step S1: The bentonite is wet-milled to obtain a pre-treated slurry, which is placed in a reaction vessel. The pre-treated slurry is then subjected to stratified detection. Based on the vibration frequency and particle size distribution width of each layer of pre-treated slurry, wet milling characteristic values ​​are generated to determine whether the pre-treated slurry meets the reaction requirements of the organic modifier. Step S2: In response to the pretreated slurry not meeting the reaction requirements of the organic modifier, the wet grinding deviation value is calculated based on the wet grinding characteristic value and the wet grinding characteristic threshold. Based on the comparison result of the wet grinding deviation value and the preset wet grinding deviation threshold, an interlayer stripping aid is added to the reactor or the stirring power and stirring time of the reactor are adjusted. In response to the pretreated slurry meeting the reaction requirements of the organic modifier, nitrogen gas of a preset flow rate is introduced into the reactor to heat the pretreated slurry. Step S3: Determine whether the intercalation reaction of the organic modifier is sufficient based on the viscosity change rate and conductivity change rate of the organic modifier in each layer of pretreated slurry. If the intercalation reaction of the organic modifier is insufficient, determine the temperature optimization value based on the viscosity difference of the organic modifier in each layer of pretreated slurry and the preset flow rate of nitrogen to ensure that the intercalation reaction of the organic modifier is sufficient. Step S4: In response to the complete intercalation reaction of the organic modifier, a multivalent ionic crosslinking agent is added to the modified slurry generated after the complete intercalation reaction of the organic modifier to prepare bentonite gel. Step S5: Determine whether the suspension capacity of the bentonite gel is stable based on the decrease in conductivity of the modified slurry or the variable curve of viscosity of the modified slurry with temperature optimization process. If the suspension capacity of the bentonite gel is unstable, determine whether the suspension capacity of the bentonite gel meets the standard based on real-time monitoring of the pH value of the modified slurry.

[0025] Please see Figure 2 As shown, this is a logic diagram for determining whether the pretreated slurry meets the reaction requirements of the organic modifier in an embodiment of the present invention. The process of generating wet milling characteristic values ​​based on the vibration frequency and particle size distribution width of each layer of pretreated slurry includes... The resonant frequency is determined by the ratio of the mean vibration frequency of each layer of pretreatment slurry to the reference vibration frequency. The ratio of the mean particle size distribution width of each layer of pretreated slurry to the reference particle size distribution width is determined as the particle size factor. The weighted sum of the resonance frequency and the particle size factor is determined to be the characteristic value of wet milling; If the wet milling characteristic value is less than or equal to the wet milling characteristic threshold, the pretreated slurry is determined to meet the reaction requirements of the organic modifier. If the wet milling characteristic value is greater than the wet milling characteristic threshold, the pretreated slurry is determined to not meet the reaction requirements of the organic modifier.

[0026] Specifically, the reference vibration frequency is the average of several vibration frequencies of the pretreated slurry in historical experiments when the pretreated slurry met the reaction requirements of the organic modifier, and the reference particle size distribution width is the average of several particle size distribution widths of the pretreated slurry in historical experiments when the pretreated slurry met the reaction requirements of the organic modifier.

[0027] Specifically, the vibration frequency can be measured using a rotational rheometer with a small amplitude oscillatory shear test, applying a sinusoidal oscillatory shear strain to the slurry. The bentonite particle size in the pretreated slurry can be obtained using a laser particle size analyzer. The first particle size corresponding to a cumulative volume distribution of 10%, the second particle size corresponding to a cumulative volume distribution of 50%, and the third particle size corresponding to a cumulative volume distribution of 90% are obtained. The particle size distribution width is calculated as (third particle size - first particle size) / second particle size, where the units of the first, second, and third particle sizes are all mm. Only the numerical values ​​are taken in the above formula calculation, and will not be elaborated further here.

[0028] Specifically, the sum of the weighting coefficients of the resonance frequency and the particle size factor is 1. Since the resonance frequency has a greater influence on the determination of the uniformity of the pretreated slurry reaction, the weighting coefficient of the resonance frequency is 0.7 and the weighting coefficient of the particle size factor is 0.3.

[0029] It is understandable that the purpose of setting the wet milling characteristic threshold is to characterize the uniformity of the pretreated slurry and improve the accuracy of judging whether the pretreated slurry meets the reaction requirements of the organic modifier. Optionally, the wet milling characteristic threshold can be in the range of 0.95 to 1.05, and preferably, the wet milling characteristic threshold is 1.0.

[0030] Understandably, using the ratio of the average vibration frequency to the reference vibration frequency as the resonant frequency can objectively reflect the vibration response characteristics of the slurry during wet milling. Using the ratio of the average particle size distribution width to the reference particle size distribution width as the particle size factor can accurately characterize the uniformity and fineness of slurry particle dispersion, directly reflecting the wet milling effect. By calculating the wet milling characteristic value through the resonant frequency and particle size factor, a quantitative characterization of the slurry state during the wet milling process can be achieved, avoiding the one-sidedness of evaluation by a single parameter.

[0031] In one specific embodiment, 10 parts by weight of natural bentonite raw material were selected and prepared into a bentonite suspension with a solid content of 10%. 0.5 parts of surfactant stabilizer were added to the suspension, and a low-speed stirrer was started and stirred at 500 r / min for 25 min to initially disperse the bentonite particles evenly, resulting in a bentonite slurry to be wet-milled. This slurry was continuously fed into a pre-tuned wet mill, with the feed rate controlled at 2.5 L / h, and wet milling continued for 35–50 min. In this embodiment, the wet milling time was 42 min. During the wet milling process, the initial dispersion state of the slurry at the outlet of the grinding chamber was monitored in real time to obtain a uniform... The pretreated slurry, after wet milling, is introduced into the reactor through a filter screen. The reactor inlet is closed, and 0.3 parts of nitrogen gas are introduced. The mixture is allowed to stand for 8-12 minutes (10 minutes in this embodiment), allowing the pretreated slurry to naturally form three layers from top to bottom within the reactor: an upper layer, a middle layer, and a lower layer. Along the height of the reactor, three detection points are set at 1 / 3 of the distance from the top of the reactor (upper layer), the middle of the reactor body (middle layer), and 1 / 3 of the distance from the bottom of the reactor (lower layer). The vibration frequency of each layer of pretreated slurry is collected using a rotational rheometer, and the particle size distribution width of each layer of pretreated slurry is collected using a laser particle size analyzer.

[0032] In one specific embodiment, the upper layer has an average vibration frequency of 118 Hz, a first particle size of 0.05 mm, a second particle size of 0.12 mm, and a third particle size of 0.21 mm, with a particle size distribution width of (0.21-0.05) / 0.12=1.33; the middle layer has an average vibration frequency of 122 Hz, a first particle size of 0.048 mm, a second particle size of 0.118 mm, and a third particle size of 0.205 mm, with a particle size distribution width of (0.205-0.048) / 0.118=1.33; and the lower layer has an average vibration frequency of 120 Hz, a first particle size of 0.052 mm, and a second particle size of 0.122 mm. The third particle size is 0.215 mm, and the particle size distribution width is (0.215-0.052) / 0.122=1.33. Therefore, the average vibration frequency is (118+122+120) / 3=120Hz, and the resonance frequency is 120 / 120=1.0. The average particle size distribution width is (1.33+1.33+1.33) / 3=1.33, and the particle size factor is 1.33 / 0.8=1.66. The wet grinding characteristic value is 1.0×0.7+1.66×0.3=1.2. This value is greater than the wet grinding characteristic threshold of 1.0, so it is determined that the pretreated slurry does not meet the reaction requirements of the organic modifier.

[0033] Specifically, this invention constructs a comprehensive wet milling characteristic value by detecting the vibration frequency and particle size distribution width of the slurry after stratification. This value can quantitatively reflect the degree of dissociation of bentonite particles, particle size uniformity, and slurry structure stability after wet milling, providing an objective and quantifiable standard for judging the pretreatment effect. By placing the pretreated slurry in the reaction vessel and immediately performing stratification detection and calculating the characteristic value, it is possible to determine in real time whether it meets the requirements of the subsequent organic modification reaction for the state of the base material, thereby further improving the stability of the method for preparing stable suspended bentonite thickening gel.

[0034] Please see Figure 3 As shown, this is a logic diagram illustrating the process of adding an interlayer stripping agent or adjusting the stirring power and time of a reactor based on a comparison between the wet grinding deviation value and a preset wet grinding deviation threshold, according to an embodiment of the present invention. The process of adding an interlayer stripping agent or adjusting the stirring power and time of a reactor based on a comparison between the wet grinding deviation value and a preset wet grinding deviation threshold includes... The difference between the wet grinding characteristic value and the wet grinding characteristic threshold is calculated as the wet grinding deviation value; If the wet grinding deviation value is less than or equal to the first wet grinding deviation threshold, then it is determined that the stirring power and stirring time of the reactor should be adjusted. If the wet grinding deviation value is greater than the first wet grinding deviation threshold and less than or equal to the second wet grinding deviation threshold, it is determined that an interlayer stripping agent is added to the reactor at the first preset ratio. If the wet grinding deviation value is greater than the second wet grinding deviation threshold, it is determined that an interlayer stripping agent will be added to the reactor at the second preset ratio.

[0035] Specifically, the first wet grinding deviation threshold is less than the second wet grinding deviation threshold.

[0036] It is understandable that the purpose of setting the wet milling deviation threshold is to characterize the degree of deviation of the pretreated slurry from meeting the reaction requirements of the organic modifier. Optionally, the value range of the first wet milling deviation threshold is 0.2 to 0.3, preferably 0.25, and the value range of the second wet milling deviation threshold is 0.4 to 0.5, preferably 0.45.

[0037] Understandably, by setting a first wet grinding deviation threshold and a second wet grinding deviation threshold, the wet grinding deviation value is divided into multiple deviation ranges, thereby enabling graded and quantitative judgment of the degree of deviation in the wet grinding process and improving the control accuracy of the wet grinding process.

[0038] Specifically, in order to promote further dispersion and uniform distribution of particles, the stirring power is increased and the stirring time is extended. Optionally, the stirring power is increased to 10% to 30% of the original stirring power, preferably to 20% of the original stirring power, and the stirring time is extended to 20% to 50% of the original stirring time, preferably to 30% of the original stirring time.

[0039] In a specific embodiment, the first wet grinding deviation threshold is set to 0.25, the second wet grinding deviation threshold can be 0.45, the original stirring power is 1.5kW, and the original stirring time is 25min. If the calculated wet grinding deviation value is 0.2, which is less than the first wet grinding deviation threshold, it is preferable to increase the stirring power to 20% of the original stirring power, that is, the adjusted stirring power is 1.5kW×(1+20%)=1.8kW, and it is preferable to extend the stirring time to 30% of the original stirring time, that is, the adjusted stirring time is 25min×(1+30%)=32.5min.

[0040] Specifically, the preset ratio is a pre-set percentage of the mass of the interlayer stripping agent to the mass of the dry bentonite in the reactor. The first preset ratio should be determined based on the moderate deviation of the slurry having a certain degree of dissociation but insufficient interlayer opening, requiring chemical additives to assist in stripping. It is preferably 1.5%, that is, 1.5 grams of interlayer stripping agent are added for every 100 grams of dry bentonite. The second preset ratio should be determined based on the severe deviation of wet milling pretreatment being seriously insufficient, with tightly agglomerated particles, requiring sufficient chemical additives for strong intercalation and dispersion in order to effectively open the interlayer structure. It is preferably 3%.

[0041] In a specific embodiment, the first wet grinding deviation threshold is set to 0.25, and the second wet grinding deviation threshold can be 0.45. If the calculated wet grinding deviation value is 0.3, which is greater than the first wet grinding deviation threshold and less than the second wet grinding deviation threshold, then it is determined that an interlayer stripping agent is added to the reaction vessel in the first preset ratio and stirred for 15 minutes.

[0042] In a specific embodiment, the first wet grinding deviation threshold is set to 0.25, and the second wet grinding deviation threshold can be 0.45. If the calculated wet grinding deviation value is 0.5, which is greater than the second wet grinding deviation threshold, it is determined that the interlayer stripping agent is added to the reaction vessel in the second preset ratio and stirred for 20 minutes.

[0043] Specifically, this invention, by taking corrective measures when the pretreated slurry does not meet the reaction requirements of the organic modifier, and calculating the wet grinding deviation value, determines whether to add an interlayer stripping aid to the pretreated slurry for chemically assisted dissociation or adjust the stirring power and time to enhance physical shear by comparing the wet grinding deviation value with a threshold. This achieves precise input of energy and chemicals. When the pretreated slurry meets the requirements, the core purpose of introducing nitrogen at a preset flow rate is to replace the air in the reactor before heating, creating an inert environment. This effectively prevents the exchangeable cations between bentonite layers and the subsequently added organic modifier from being oxidized during heating. The preset flow rate and subsequent heating treatment together ensure that the initial physicochemical environment is strictly consistent and controlled when each qualified material enters the modification reaction stage. This response achieves a seamless transition from pretreatment quality inspection to the start of the modification reaction, improving the continuity of the production process and further enhancing the stability of the method for preparing stable suspended bentonite thickening gel.

[0044] Specifically, the process of calculating the change-related index based on the viscosity change rate and conductivity change rate of the organic modifier intercalation in each layer of the pretreatment slurry includes the following steps: Collect several viscosity values ​​and several conductivity values ​​within a preset time period; Calculate the viscosity change rate of adjacent viscosity values ​​within a preset time period to generate a viscosity change dataset; Calculate the rate of change of conductivity between adjacent conductivity values ​​within a preset time period to generate a conductivity change dataset; The correlation between the viscosity change dataset and the conductivity change dataset is calculated based on the Pearson correlation coefficient formula to generate a correlation index.

[0045] Specifically, the preset time starts from the time when the organic modifier is added to the pretreatment slurry and ends when the organic modifier has completely evaporated in the pretreatment slurry and the viscosity and conductivity both tend to be in equilibrium. The single viscosity change rate = (current viscosity value - previous viscosity value) / previous viscosity value, and the single conductivity change rate = (current conductivity value - previous conductivity value) / previous conductivity value. The unit of viscosity value is mPa·s and the unit of conductivity value is mS / cm. Only the numerical values ​​are used in the above calculations.

[0046] Specifically, when calculating the correlation index, the viscosity change rate and conductivity change rate at different times within a preset time period are first set as the corresponding sample data, and then the Pearson correlation coefficient formula is used for calculation. The Pearson correlation coefficient formula is as follows: Where r is the correlation index, i is the subscript variable representing the i-th observation data point, and n represents the total number of observation data points. This represents the i-th observation of variable X. The sample mean representing variable X. This represents the i-th observation of variable Y. The sample mean of variable Y.

[0047] In one specific embodiment, a monitoring time point is set every 2 minutes within an 8-minute period. The viscosity change rate set is calculated as [0.200, 0.250, 0.200, 0.111, 0.050], and the conductivity change rate set is calculated as [0.200, 0.250, 0.133, 0.0588, 0.0278]. The change correlation index is calculated to be 0.95 using the Pearson correlation coefficient formula.

[0048] Specifically, the sufficiency of the intercalation reaction of the organic modifier is determined based on the change-related index, among which, Under the condition that no interlayer stripping agent is added to the reactor and the stirring power and stirring time of the reactor are not adjusted, if the change correlation index is greater than or equal to the first change correlation index threshold, the intercalation reaction of the organic modifier is determined to be sufficient; if the change correlation index is less than the first change correlation index threshold, the intercalation reaction of the organic modifier is determined to be insufficient. Under the condition that interlayer stripping agent is added to the reactor at a first preset ratio, if the change correlation index is greater than or equal to the second change correlation index threshold, the intercalation reaction of the organic modifier is determined to be sufficient; if the change correlation index is less than the second change correlation index threshold, the intercalation reaction of the organic modifier is determined to be insufficient. Under the condition that an interlayer stripping agent is added to the reactor at a second preset ratio or the stirring power and stirring time of the reactor are adjusted, if the change correlation index is greater than or equal to the third change correlation index threshold, the intercalation reaction of the organic modifier is determined to be sufficient; if the change correlation index is less than the third change correlation index threshold, the intercalation reaction of the organic modifier is determined to be insufficient.

[0049] Specifically, the change-related index thresholds include a first change-related index threshold, a second change-related index threshold, and a third change-related index threshold, wherein the first change-related index threshold is greater than the second change-related index threshold, and the second change-related index threshold is greater than the third change-related index threshold.

[0050] Understandably, the purpose of setting the change correlation index is to characterize the magnitude of the correlation between conductivity and viscosity under different reaction conditions. Optionally, the value range of the first change correlation index threshold is 0.85 to 0.95, preferably 0.9. The value range of the second change correlation index threshold is 0.8 times that of the first change correlation index threshold, preferably 0.72. The value range of the third change correlation index threshold is 0.7 times that of the first change correlation index threshold, preferably 0.63.

[0051] Understandably, by changing the relevant index threshold to accurately determine the stability and uniformity of the slurry state, it is possible to effectively distinguish the fluctuations in the intercalation reaction of organic modifiers and improve the identification accuracy of the intercalation reaction state of organic modifiers.

[0052] Specifically, the process of determining the optimal temperature value based on the viscosity difference of the organic modifier intercalation in each layer of the pretreated slurry and the preset nitrogen flow rate includes the following steps: The upper temperature limit is determined based on the preset flow rate; Calculate the average viscosity difference of the pretreatment slurry in adjacent layers to determine the required temperature value; If the temperature requirement is less than the upper temperature limit, then the optimal temperature value is determined to be the temperature requirement. If the temperature requirement is greater than or equal to the upper temperature limit, then the optimal temperature value is determined to be the upper temperature limit.

[0053] In one specific embodiment, the preset nitrogen flow rate was 1.5 parts, i.e., 0.8 L / min. Based on the preset nitrogen flow rate of 0.8 L / min, the upper temperature limit was determined to be 65℃ through experimental calibration. The viscosity values ​​of the slurry samples from the upper, middle, and lower layers of the reactor were measured using a rotational rheometer after the initial intercalation of the organic modifier (adding 0.5 parts of organic modifier and stirring for 5 min). The obtained viscosity values ​​were 180 mPa·s for the upper layer and 1... With a lower layer viscosity of 75 mPa·s and a lower layer viscosity of 182 mPa·s, the viscosity difference between the upper and middle layers is calculated as |180-175|=5 mPa·s, and the viscosity difference between the middle and lower layers is calculated as |175-182|=7 mPa·s. The average of the two differences is (5+7) / 2=6 mPa·s. Through experiments, the temperature requirement corresponding to a viscosity difference of 6 mPa·s is determined to be 68℃. Therefore, the temperature requirement is greater than the upper temperature limit, and the optimal temperature value is determined to be 65℃.

[0054] Specifically, the upper temperature limit is the maximum temperature value among several temperature values ​​that, under the condition that the intercalation reaction of the organic modifier is insufficient in several historical experiments, can determine the preset flow rate of nitrogen to protect the slurry from oxidation and prevent the slurry reaction from being affected by high temperature.

[0055] Specifically, the temperature requirement value is the difference between the average temperature value corresponding to the viscosity difference of the pretreated slurry under the condition that the intercalation reaction of the organic modifier is insufficient in several historical experiments, and the temperature value that can make the intercalation reaction of the organic modifier sufficient again after temperature adjustment.

[0056] Specifically, the process of determining whether the suspension capacity of bentonite gel is stable based on the decrease in conductivity of the modified slurry or the viscosity-temperature variation curve of the modified slurry during optimization includes the following steps: If the temperature was not optimized before the modified slurry was generated, several conductivity values ​​were sorted according to a preset time. The conductivity value at the end of the sort was selected as the organic conductivity value. The conductivity value at which the conductivity stabilized again after the addition of the multivalent ion crosslinking agent was determined as the crosslinking conductivity value. The difference between the organic conductivity value and the crosslinking conductivity value was calculated as the amount of conductivity decrease. If temperature optimization is performed before the modified slurry is generated, the slope of the variable curve can be obtained.

[0057] Specifically, the decrease in conductivity = organic conductivity value - cross-linked conductivity value, with the unit of conductivity value being mS / cm. When obtaining the slope of the variable curve, the specific change value of temperature increase is determined, and this change value is divided into several equally spaced sub-values. The variable curve is plotted with the sub-values ​​as the abscissa and the viscosity corresponding to the sub-values ​​as the ordinate.

[0058] Specifically, the viscosity measured after the system stabilizes at the corresponding temperature point is used as the ordinate to plot the variation curve.

[0059] Specifically, this invention, by simultaneously monitoring two key physical parameters—viscosity change rate and conductivity change rate—can dynamically reveal the essence of the reaction from different dimensions. Viscosity change rate directly reflects changes in the system's microstructure. The insertion of organic modifiers into the bentonite interlayers increases the interlamellar spacing and alters the hydrodynamic interactions between particles, typically leading to significant and regular changes in system viscosity. Monitoring its change rate can reflect the structural reconstruction kinetics induced by the intercalation reaction in real time. Conductivity change rate can sensitively capture changes in the ionic environment. Intercalation reactions are often accompanied by cation exchange and changes in the concentration of free ions in the system. Conductivity change rate can monitor the progress of this electrochemical process in real time. Under conditions indicating incomplete reaction, the viscosity difference reflects the distribution of mass transfer resistance within the reaction system. Under normal circumstances, the large differences in viscosity among the layers indicate that the diffusion and intercalation processes of the organic modifier in the slurry are inconsistent. Increasing the temperature is an effective physical means to reduce the viscosity of the system and promote diffusion mass transfer. The preset nitrogen flow rate, as a previously set protective process parameter, is related to the heat transfer efficiency of the reaction environment and the risk of local hot spots. The flow rate affects the flow state of the atmosphere inside the reactor, thus affecting heat exchange. By combining the above two key parameters to calculate the optimized temperature value, it can be ensured that each batch of intercalation reaction truly reaches a sufficient and complete state, avoiding problems such as organic modifier residue and insufficient interlayer exchange rate caused by incomplete reaction. This ensures that the organic bentonite base material has optimal compatibility and interlayer spacing, thereby further improving the stability of the preparation method of stable suspended bentonite thickening gel.

[0060] Specifically, the stability of the suspension capacity of bentonite gel is determined based on the decrease in conductivity of the modified slurry or the viscosity variation curve of the modified slurry during temperature optimization. If the decrease in conductivity is greater than the threshold for the decrease in conductivity or the slope of the variable curve is within the allowable fluctuation range, then the suspension capacity of the bentonite gel is determined to be stable. If the decrease in conductivity is not greater than the threshold for the decrease in conductivity, or if the slope of the variable curve is not within the allowable fluctuation range, then the suspension capacity of the bentonite gel is determined to be unstable.

[0061] It can be understood that the decrease in conductivity directly reflects the degree of ion exchange and complexation reaction between the multivalent ion crosslinking agent and the negatively charged bentonite sheets and organic modifier. The greater the decrease, the more ion crosslinking points are formed and the denser the gel network. Optionally, the threshold value of the decrease in conductivity is 0.2 to 0.3 times the organic conductivity value. Preferably, the threshold value of the decrease in conductivity is 0.25 times the organic conductivity value.

[0062] It is understandable that the viscosity of bentonite gel comes from the spatial network structure formed by the cross-linking of bentonite sheets through organic modifiers and multivalent ions. When the temperature rises, more physical cross-linking points will be formed or existing cross-linking points will become more compact.

[0063] Specifically, the allowable fluctuation range is determined through calibration experiments. Multiple batches of bentonite gels with satisfactory suspension capacity are prepared under standard process conditions. The variation curves of these gels during the programmed temperature rise process from 30℃ to 60℃ are plotted and linearly fitted. The statistical average and standard deviation of the slope values ​​are calculated. Preferably, for organic bentonite gels with a solid content of 5% to 10%, the allowable fluctuation range is 15 mPa·s / ℃ to 60 mPa·s / ℃.

[0064] Understandably, the conductivity decrease threshold, as a criterion for judging the degree of crosslinking stability, can intuitively reflect the crosslinking effect of multivalent ion crosslinking agents on the slurry. Setting an allowable fluctuation range can accurately characterize the stability and trend consistency of viscosity changes during temperature optimization, effectively identify whether the microstructure of the slurry is stable under the temperature field. By setting the conductivity decrease threshold and the allowable fluctuation range of the viscosity variation curve, a two-dimensional judgment of the suspension capacity of bentonite gel can be achieved, which can be adapted to both temperature-optimized and unoptimized working conditions, thereby improving the applicability and judgment accuracy.

[0065] In one specific embodiment, 7 parts of organic modifier were added to the reactor, the stirrer was started and maintained at 1.8kW power, and the conductivity value of the modified slurry was monitored in real time. Ten sets of data were continuously collected at preset times (one set every 5 minutes), namely: 320μS / cm, 315μS / cm, 310μS / cm, 308μS / cm, 306μS / cm, 305μS / cm, 304μS / cm, 304μS / cm, 303μS / cm, and 303μS / cm. The 10 sets of conductivity values ​​were sorted according to the collection time, and the conductivity value at the end of the sorted list, 303μS / cm, was selected. cm was used as the organic conductivity value. A multivalent ionic crosslinking agent (1.5 parts by weight) was added to the reactor. The mixture was continuously stirred and the conductivity value was monitored in real time. After the conductivity fluctuated and then stabilized for 30 minutes, the conductivity value at this time was recorded as 220 μS / cm. This value is the crosslinking conductivity value. According to the formula, conductivity decrease = organic conductivity value - crosslinking conductivity value, the conductivity decrease was calculated to be 83 μS / cm. The preset conductivity decrease threshold is 75.75 μS / cm. Since 83 μS / cm > 75.75 μS / cm, the suspension ability of the bentonite gel is determined to be stable.

[0066] In one specific embodiment, 7 parts of organic modifier were added to the reactor. At the optimized temperature of 45°C, the viscosity of the modified slurry was monitored in real time. Data was collected every 3 minutes for 15 consecutive minutes. The viscosity values ​​at each time point were recorded, and a viscosity-temperature-optimized curve was plotted. The slope of the curve was 28 mPa·s / min. The preset allowable fluctuation range of the slope of the viscosity-temperature-optimized curve was 15 mPa·s / °C to 60 mPa·s / °C. Since 28 mPa·s / min was within the allowable fluctuation range, the suspension capacity of the bentonite gel was determined to be stable.

[0067] Please see Figure 4 As shown, this is a logic diagram for determining whether the suspension capacity of bentonite gel meets the standard according to an embodiment of the present invention. The process of determining whether the suspension capacity of bentonite gel meets the standard based on real-time monitoring of the pH value of the modified slurry includes: The pH value of the modified slurry is monitored in real time to plot the pH fluctuation curve; The predicted addition rate of the multivalent ion crosslinking agent was determined based on the pH fluctuation curve; The suspension capacity of bentonite gel is determined based on the rate difference between the predicted and actual addition rates. If the rate difference is less than the rate difference threshold, the suspension capacity of the bentonite gel is deemed to meet the standard. If the rate difference is greater than or equal to the rate difference threshold, the suspension capacity of the bentonite gel is determined to be substandard and an alarm signal is issued.

[0068] Specifically, the pH fluctuation curve is plotted with several monitoring times as the horizontal axis and the corresponding pH value at each monitoring time as the vertical axis.

[0069] Specifically, the predicted addition rate is the addition rate of the multivalent ion crosslinking agent required to achieve the required suspension capacity of bentonite gel at different pH values ​​in several historical experiments. The rate difference = predicted addition rate - actual addition rate, where the unit of rate is mL / min.

[0070] It is understandable that the purpose of setting the rate difference threshold is to characterize whether the pH fluctuation of the modified slurry meets the requirements of stable suspension ability of bentonite thickening gel. Therefore, the range of the rate difference threshold is 0.2 mL / min to 0.5 mL / min, and preferably, the rate difference threshold can be 0.3 mL / min.

[0071] Understandably, by setting a rate difference threshold, the degree of matching between the pH fluctuation curve and the addition of the crosslinking agent can be reflected in real time, accurately characterizing the stability of the crosslinking reaction of the slurry system. The deviation between the predicted addition rate and the actual addition rate can be quantitatively judged to achieve unified and standardized judgment criteria, effectively improving the consistency of product quality judgment under different batches and different working conditions.

[0072] In one specific embodiment, 7 parts of organic modifier were added to the reactor. The modified slurry was subjected to a programmed temperature increase from 45°C to 65°C at an optimized temperature of 45°C, with a heating rate of 2°C / min. The viscosity of the modified slurry at different temperatures was monitored in real time. Data was collected every 3°C for 11 consecutive sets. The collected temperature and corresponding viscosity data were as follows: 30°C = 175 mPa·s, 33°C = 192 mPa·s, 36°C = 208 mPa·s, 39°C = 225 mPa·s, 42°C = 242 mPa·s, and 45°C = 258 mPa·s. 48℃ corresponds to 275 mPa·s, 51℃ to 292 mPa·s, 54℃ to 308 mPa·s, 57℃ to 325 mPa·s, and 60℃ to 342 mPa·s. The slope of this variable curve was calculated through linear fitting, yielding a slope of 5.6 mPa·s / ℃. Since 5.6 mPa·s / ℃ is outside the allowable fluctuation range, it is necessary to further determine whether the suspension capacity of the bentonite gel meets the standard based on real-time monitoring of the modified slurry's pH value. Therefore, an online pH monitor was activated to monitor the pH value of the modified slurry in the reactor in real time, collecting one set of pH data every 2 minutes. Twenty consecutive pH data sets were collected over a period of 40 minutes. A pH fluctuation curve was plotted with the corresponding pH values ​​at each monitoring time point on the x-axis and the values ​​on the y-axis. The 20 pH data sets collected were: 8.9, 8.8, 8.9, 8.7, 8.8, 8.9, 8.7, 8.8, 8.6, 8.7, 8.8, 8.7, 8.6, 8.7, 8.8, 8.7, 8.6, 8.7, 8.8, and 8.7. Based on this, the pH fluctuation curve was plotted, and the amplitude and trend of pH fluctuations were analyzed through data fitting. Specifically, when the pH fluctuation amplitude was ≤0.2, The predicted addition rate was 0.03 parts / min. The maximum pH fluctuation range was 8.9 and the minimum was 8.6. After fitting, the predicted addition rate was determined to be 0.035 parts / min. The actual addition rate of the preset multivalent ion crosslinking agent was 0.03 parts / min. According to the calculation method of "rate difference = |predicted addition rate - actual addition rate|", the rate difference in this case was |0.035 - 0.03| = 0.005 parts / min. The preset rate difference threshold was 0.01 parts / min. Since 0.005 parts / min < 0.01 parts / min, the suspension capacity of the bentonite gel was determined to be up to standard.

[0073] Specifically, this invention utilizes the addition of a multivalent ionic crosslinking agent to achieve ionic crosslinking with negatively charged bentonite sheets. This process simultaneously fixes or consumes free ions in the system, leading to a significant decrease in conductivity. The magnitude and rate of this conductivity decrease directly quantify the degree and speed of the crosslinking reaction. Furthermore, the viscosity of the gel is extremely sensitive to temperature; analyzing the variation curve allows for the assessment of the gel network's thermal stability, structural strength, and thixotropy. Using different judgment criteria for modified slurries obtained through different control methods improves the accuracy of determining the suspension capacity of the bentonite gel. Additionally, pH significantly affects the surface charge of the bentonite sheets, the state of the organic modifier, and the crosslinking behavior of multivalent ions. Real-time control of the pH of the reaction system within the optimal window is crucial to ensuring the crosslinking reaction proceeds along the predetermined path. Under conditions where the suspension capacity of the bentonite gel is deemed unstable, verification of its suspension capacity based on pH fluctuations avoids resource waste caused by overly stringent judgment criteria, thereby further improving the stability of the method for preparing stable suspended bentonite thickening gels.

[0074] Specifically, by weight, the components for preparing the bentonite thickening gel include: 10-15 parts bentonite, 5-10 parts organic modifier, 1-2 parts polyvalent ion crosslinking agent, 2-6 parts rheology modifier, 1-4 parts surfactant stabilizer, 1-2 parts nitrogen, and 1-2 parts interlayer stripping agent.

[0075] Example 1 1. Bentonite thickening gel formulation (parts by weight) 10-15 parts bentonite, 5-10 parts organic modifier, 1-2 parts polyvalent ion crosslinking agent, 2-6 parts rheology modifier, 1-4 parts surfactant stabilizer, 1-2 parts nitrogen, and 1-2 parts interlayer stripping agent. Specifically, the organic modifier can be a quaternary ammonium salt cationic surfactant, whose main components are 30% hexadecyltrimethylammonium chloride, 40% octadecyltrimethylammonium chloride, and 30% benzyldimethyloctadecylammonium chloride, and the auxiliary components are 50% γ-aminopropyltriethoxysilane and 50% γ-glycidoxypropyltrimethoxysilane. The main components account for 70% to 90% of the total mass of the organic modifier, and the auxiliary components account for 10% to 30% of the total mass of the organic modifier. The polyvalent ionic crosslinking agent can be an aluminum-based crosslinking agent or a zirconium-based crosslinking agent. Specifically, the rheology modifier is mainly composed of biopolymers and natural clay, with a small amount of synthetic polymers. Its main components are 40% xanthan gum and 60% guar gum, and the auxiliary components are 30% attapulgite and 70% sodium carboxymethyl cellulose. The main components account for 60% to 80% of the total mass of the rheology modifier, and the auxiliary components account for 20% to 40% of the total mass of the rheology modifier. Specifically, the surfactant stabilizer can be isononyl isononanoate, or a combination of nonionic surfactant and polymeric stabilizer. Its main components are 60% Tween-80 and 40% alkyl glycoside, and the auxiliary components are 30% polyvinylpyrrolidone and 70% polyethylene glycol. The main components account for 50% to 70% of the total mass of the surfactant stabilizer, and the auxiliary components account for 30% to 50% of the total mass of the surfactant stabilizer. Specifically, the interlayer stripping agent can be propylene glycol carbonate or a small molecule intercalation type, with its core components being 20% ​​urea, 25% ethylene glycol, 30% glycerol, and 25% dimethyl sulfoxide.

[0076] 2. Comparative Example 1 Standard bentonite thickening gel formulation (parts by weight) The mixture consists of 12 parts bentonite, 175 parts deionized water, 0.5 parts sodium pyrophosphate, 6 parts propylene glycol, and 0.2 parts preservative. The difference between this and Example 1 is that no additives were considered to ensure the uniformity of the bentonite thickening gel under long-term storage at high temperatures and in high-salt environments.

[0077] Example 2 1. Preparation process After wet grinding of bentonite, the solid content was controlled at 10%. After stratified testing, the wet grinding characteristic value was slightly higher than the wet grinding characteristic threshold. The wet grinding deviation value was calculated. The deviation value was less than the preset wet grinding deviation threshold. The stirring power of the reactor was adjusted to 1.2 times the original power, and the stirring time was extended by 20 minutes. After testing again, the wet grinding characteristic value met the requirements. Nitrogen gas of the preset flow rate was introduced, the slurry was heated to 120℃ and kept at a constant temperature, and an organic modifier was added. The intercalation reaction was carried out for 40 minutes and matured for 2 hours. Initial monitoring showed that the viscosity change rate and conductivity change rate of some layers of slurry did not meet the standards, indicating that the intercalation reaction was insufficient. Based on the viscosity difference of each layer and the nitrogen flow rate, the temperature optimization value was determined to be 125℃. After heating, the reaction was continued for 10 minutes. After monitoring again, the intercalation reaction was determined to be sufficient. A multivalent ion crosslinking agent was added dropwise, the pH value was adjusted to 9.0, and the crosslinking reaction was carried out for 60 minutes. Rheology modifier and surfactant stabilizer were added, and high shear dispersion was carried out for 30 minutes to form a homogeneous gel. After cooling to room temperature, it was packaged and sealed to obtain the finished product.

[0078] 2. Comparative Example 2 Conventional bentonite thickening gel preparation process Add approximately 90% of the formula amount of deionized water to a mixing tank. While stirring rapidly, slowly add sodium pyrophosphate and stir until completely dissolved. While continuing to stir rapidly, slowly and evenly sprinkle bentonite powder into the liquid vortex. After all the bentonite has been added, continue to stir at high speed for 10-15 minutes to ensure that all powder is wetted by the liquid and a uniform slurry is formed. Add the remaining deionized water, propylene glycol, and preservative. Switch the high-speed stirring to medium-low speed stirring for 20-30 minutes. Stop stirring and let the slurry stand for at least 4 hours. After maturation, turn on low speed stirring for a few minutes to stir the gel evenly to obtain the finished product. The difference between this and Example 2 is that it does not take into account the need to adjust the stirring method when the slurry reaction is insufficient during bentonite preparation, or the need to adjust the reaction temperature when the intercalation reaction is insufficient to reduce batch fluctuations of the bentonite thickening gel.

[0079] Example 3 1. Testing methods for bentonite thickening gel products In the preparation stages of bentonite gel wet milling pretreatment, organic intercalation reaction, multivalent ion crosslinking, rheology and stabilizing agent dispersion, and overall temperature optimization, the conductivity, viscosity, and pH data of the modified slurry are collected in real time by online sensing equipment. The structural stability formed by intercalation and crosslinking is determined by whether the decrease in conductivity reaches a preset threshold. The stability of suspension performance under temperature fluctuations is evaluated based on the slope and steady-state characteristics of the viscosity-temperature curve. Finally, the acid-base compatibility and suspension capacity of the system are determined in real time by combining the set pH value.

[0080] 2. Comparative Example 3 After the gel product is prepared and cooled to room temperature, a test slurry is prepared according to standard specifications. The suspension rate at 2 hours and 24 hours is measured by measuring cylinder static test to characterize the anti-settling performance. The apparent viscosity at a fixed shear rate at room temperature is measured by rotational viscometer and the gel value is determined. At the same time, the swelling capacity, particle dispersion uniformity and other indicators are compared with the qualified threshold to comprehensively complete the qualification judgment of the finished product. The difference between this and Example 3 is that the online detection of the suspension capacity of the bentonite thickening gel is not considered to save process time, and the pH fluctuation is used to further verify whether the suspension capacity of the bentonite thickening gel meets the performance of the finished product when the suspension capacity is unstable.

[0081] The data on the heat recovery rate and electrolyte resistance retention rate of the prepared bentonite thickened gel are shown in Table 1.

[0082] Table 1. Heat recovery rate and electrolyte resistance retention rate

[0083] As shown in Table 1, the bentonite thickening gel prepared in Example 1 has a high thermal recovery rate and excellent electrolyte resistance. Because the bentonite raw material is wet-milled, nitrogen gas is introduced during the heating treatment of the pretreated slurry to prevent oxidation of the slurry, and the viscosity and conductivity change rates of each layer of slurry are monitored in real time during the maturation process, and the multivalent ion crosslinking agent is added stepwise after the intercalation reaction is determined to be sufficient, the thermal recovery rate and electrolyte resistance retention rate are both outstanding.

[0084] The yield of the prepared bentonite thickening gel is shown in Table 2.

[0085] Table 2 Batch Pass Rate

[0086] As shown in Table 2, the bentonite thickening gel prepared in Example 2 has a high yield rate. During the preparation process, the degree of reaction of the slurry was detected in the wet milling step and the intercalation reaction step respectively. When the reaction was insufficient, adjustments were made in time to improve the yield rate of the single product, so that the yield rate of each batch of finished products reached above the standard and the batch fluctuation was reduced.

[0087] The average detection time of the prepared bentonite thickening gel is shown in Table 3.

[0088] Table 3 Average Detection Time

[0089] As shown in Table 3, the bentonite thickening gel prepared in Example 3 has a short average detection time. The conductivity and viscosity of the modified slurry are collected in real time by online sensing equipment to predict the stability of the suspension ability of the bentonite thickening gel. When it is determined to be unstable, the pH value monitored in real time is used to determine whether the suspension ability of the bentonite thickening gel meets the standard, which improves the detection efficiency of the finished product and saves time for subsequent processes.

[0090] It is understood that no specific limitation is made to any preset parameter or critical parameter in the embodiments of the present invention, and the above values ​​are not limited thereto. Those skilled in the art can adjust the preset parameter or critical parameter accordingly based on the needs, analysis of historical data, or equipment usage.

[0091] The technical solution of the present invention has been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the scope of protection of the present invention.

Claims

1. A method for preparing a stable suspended bentonite thickening gel, characterized in that, include: Bentonite is pretreated by wet milling to obtain a pretreated slurry, which is then placed in a reaction vessel. The pretreated slurry is subjected to stratified detection. Based on the vibration frequency and particle size distribution width of each layer of pretreated slurry, wet milling characteristic values ​​are generated to determine whether the pretreated slurry meets the reaction requirements of the organic modifier. In response to the pretreated slurry not meeting the reaction requirements of the organic modifier, a wet grinding deviation value is calculated based on the wet grinding characteristic value and the wet grinding characteristic threshold. Based on the comparison result of the wet grinding deviation value and the preset wet grinding deviation threshold, an interlayer stripping aid is added to the reactor or the stirring power and stirring time of the reactor are adjusted. In response to the pretreated slurry meeting the reaction requirements of the organic modifier, nitrogen gas of a preset flow rate is introduced into the reactor to heat the pretreated slurry. The intercalation reaction of the organic modifier is determined based on the viscosity change rate and conductivity change rate of the organic modifier in each layer of pretreated slurry. If the intercalation reaction of the organic modifier is insufficient, an optimized temperature value is determined based on the viscosity difference of the organic modifier in each layer of pretreated slurry and the preset flow rate of nitrogen to ensure that the intercalation reaction of the organic modifier is sufficient. In response to the complete intercalation reaction of the organic modifier, a multivalent ionic crosslinking agent is added to the modified slurry generated after the complete intercalation reaction of the organic modifier to prepare bentonite gel; The stability of the suspension capacity of bentonite gel is determined based on the decrease in conductivity of the modified slurry or the variable curve of viscosity of the modified slurry with temperature optimization. If the suspension capacity of bentonite gel is unstable, the standard of suspension capacity of bentonite gel is determined based on real-time monitoring of pH value of modified slurry. The resonant frequency is determined by the ratio of the mean vibration frequency of each layer of pretreatment slurry to the reference vibration frequency. The ratio of the mean particle size distribution width of each layer of pretreated slurry to the reference particle size distribution width is determined as the particle size factor. The weighted sum of the resonant frequency and the particle size factor is determined to be the wet milling characteristic value; The sum of the weighting coefficient of the resonance frequency and the particle size factor is 1; Among them, the resonance frequency has a greater impact on the determination of the uniformity of the pretreated slurry reaction, and the weighting coefficient of the resonance frequency is determined to be 0.7, and the weighting coefficient of the particle size factor is 0.

3.

2. The method for preparing a stable suspended bentonite thickened gel according to claim 1, characterized in that, The determination of whether the pretreated slurry meets the reaction requirements of the organic modifier is based on the wet milling characteristic values. If the wet milling characteristic value is less than or equal to the wet milling characteristic threshold, then the pretreated slurry is determined to meet the reaction requirements of the organic modifier. If the wet milling characteristic value is greater than the wet milling characteristic threshold, it is determined that the pretreated slurry does not meet the reaction requirements of the organic modifier.

3. The method for preparing a stable suspended bentonite thickened gel according to claim 2, characterized in that, The process of adding interlayer stripping agents or adjusting the stirring power and stirring time of the reactor based on the comparison results of the wet grinding deviation value and the preset wet grinding deviation threshold includes the following: The difference between the wet grinding characteristic value and the wet grinding characteristic threshold is calculated as the wet grinding deviation value; If the wet grinding deviation value is less than or equal to the first wet grinding deviation threshold, it is determined that the stirring power and stirring time of the reactor should be adjusted. If the wet grinding deviation value is greater than the first wet grinding deviation threshold and less than or equal to the second wet grinding deviation threshold, it is determined that an interlayer stripping agent is added to the reactor at a first preset ratio. If the wet grinding deviation value is greater than the second wet grinding deviation threshold, it is determined that an interlayer stripping agent is added to the reactor at a second preset ratio.

4. The method for preparing a stable suspended bentonite thickened gel according to claim 3, characterized in that, The process of calculating the correlation index based on the viscosity and conductivity change rates of organic modifier intercalation in each layer of pretreated slurry includes: Collect several viscosity values ​​and several conductivity values ​​within a preset time period; Calculate the viscosity change rate of adjacent viscosity values ​​within a preset time period to generate a viscosity change dataset; Calculate the rate of change of conductivity between adjacent conductivity values ​​within a preset time period to generate a conductivity change dataset; The correlation between the viscosity change dataset and the conductivity change dataset is calculated based on the Pearson correlation coefficient formula to generate a correlation index.

5. The method for preparing a stable suspended bentonite thickened gel according to claim 4, characterized in that, The sufficiency of the intercalation reaction of the organic modifier is determined based on the change-related index, among which... Under the condition that no interlayer stripping agent is added to the reactor and the stirring power and stirring time of the reactor are not adjusted, if the change correlation index is greater than or equal to the first change correlation index threshold, the intercalation reaction of the organic modifier is determined to be sufficient; if the change correlation index is less than the first change correlation index threshold, the intercalation reaction of the organic modifier is determined to be insufficient. Under the condition that interlayer stripping agent is added to the reactor at a first preset ratio, if the change correlation index is greater than or equal to the second change correlation index threshold, the intercalation reaction of the organic modifier is determined to be sufficient; if the change correlation index is less than the second change correlation index threshold, the intercalation reaction of the organic modifier is determined to be insufficient. Under the condition that an interlayer stripping agent is added to the reactor at a second preset ratio or the stirring power and stirring time of the reactor are adjusted, if the change correlation index is greater than or equal to the third change correlation index threshold, the intercalation reaction of the organic modifier is determined to be sufficient; if the change correlation index is less than the third change correlation index threshold, the intercalation reaction of the organic modifier is determined to be insufficient.

6. The method for preparing a stable suspended bentonite thickened gel according to claim 5, characterized in that, The process of determining the optimal temperature value based on the viscosity difference of the organic modifier intercalation in each layer of the pretreated slurry and the preset flow rate of nitrogen includes the following steps: The upper temperature limit is determined based on the preset flow rate; Calculate the average viscosity difference of the pretreatment slurry in adjacent layers to determine the required temperature value; If the required temperature value is less than the upper limit temperature value, then the optimized temperature value is determined to be the required temperature value. If the required temperature value is greater than or equal to the upper limit temperature value, then the optimized temperature value is determined to be the upper limit temperature value.

7. The method for preparing a stable suspended bentonite thickened gel according to claim 6, characterized in that, The process of determining whether the suspension capacity of bentonite gel is stable based on the decrease in conductivity of modified slurry or the viscosity-temperature variation curve of modified slurry during optimization includes the following steps: If the temperature optimization treatment was not performed before the modified slurry was generated, the conductivity values ​​were sorted according to the preset time, and the conductivity value at the end of the sort was selected as the organic conductivity value. The conductivity value at which the conductivity stabilized again after the addition of the multivalent ion crosslinking agent was determined as the crosslinking conductivity value. The difference between the organic conductivity value and the crosslinking conductivity value was calculated as the conductivity decrease. If temperature optimization is performed before the modified slurry is generated, the slope of the variable curve is obtained.

8. The method for preparing a stable suspended bentonite thickened gel according to claim 7, characterized in that, The stability of the suspension capacity of bentonite gel is determined based on either the decrease in conductivity of the modified slurry or the viscosity variation curve of the modified slurry during temperature optimization. If the decrease in conductivity is greater than the threshold for the decrease in conductivity or the slope of the variable curve is within the allowable fluctuation range, then the suspension capacity of the bentonite gel is determined to be stable. If the decrease in conductivity is not greater than the threshold value of the decrease in conductivity or the slope of the variable curve is not within the allowable fluctuation range, then the suspension capacity of the bentonite gel is determined based on the real-time monitoring of the pH value of the modified slurry.

9. The method for preparing a stable suspended bentonite thickened gel according to claim 8, characterized in that, The process of determining whether the suspension capacity of bentonite gel meets the standard based on real-time monitoring of the pH value of the modified slurry includes: The pH value of the modified slurry is monitored in real time to plot the pH fluctuation curve; The predicted addition rate of the multivalent ion crosslinking agent is determined based on the pH fluctuation curve. The suspension capacity of the bentonite gel is determined based on the rate difference between the predicted addition rate and the actual addition rate. If the rate difference is less than the rate difference threshold, the suspension capacity of the bentonite gel is determined to meet the standard.

10. A bentonite thickening gel prepared using the method for preparing a stable suspension bentonite thickening gel according to any one of claims 1-9, characterized in that, The components include: 10-15 parts bentonite, 5-10 parts organic modifier, 1-2 parts polyvalent ion crosslinking agent, 2-6 parts rheology modifier, 1-4 parts surfactant stabilizer, 1-2 parts nitrogen, and 1-2 parts interlayer stripping agent.

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