System and method for optimizing particle size distribution of finished bentonite

Abstract

The invention relates to a system and a method for optimizing finished bentonite particle size distribution. The system comprises grinding equipment, screening equipment, mixing equipment, a control system and at least three storage bins, the screening equipment is arranged above the at least three storage bins, discharge ports are formed in the bottoms of the at least three storage bins respectively, and weighing areas are correspondingly arranged below the discharge ports; and the weighing area is communicated with the mixing equipment. The bentonite powder with various particle size distributions can be prepared at the same time, the bentonite powder is finely divided into clear intervals before being mixed, and the bentonite powder with different particle sizes can be accurately controlled in real time according to mass fraction and particle size distribution according to needs. Besides, the production process of the bentonite is highly integrated, so that the production process is orderly carried out in one system, the circulation loss of the bentonite powder is reduced, the human intervention is reduced, and the production efficiency is further improved.

Description

Technical Field

[0001] The invention relates to the technical field of bentonite processing, and in particular to a system and method for optimizing the particle size distribution of finished bentonite products. Background Art

[0002] Bentonite is a micron-sized powder material formed by grinding various sodium bentonite of different grades. During the grinding process, due to the differences in hardness, composition, microscopic morphology and other characteristics of the raw ore, the particle size ranges of different raw ore powders in the final product are different. Therefore, in terms of particle size, bentonite is a powder material composed of particles of different sizes, and the particle distribution of different particle size ranges has a significant impact on the material performance. When bentonite is used as a casting binder, from the perspective of reducing the porosity defects of castings, the most suitable requirement is that the water content of the molding sand in the dry and wet states is low. Therefore, if the bentonite particle size is too fine, the water content of the molding sand will be too high under the premise of achieving a suitable compaction rate. At this time, the air permeability of the molding sand is too large, which is easy to cause defects such as sand sticking to the casting; from the perspective of subsequent use in pouring high-temperature metals, since bentonites of different particle sizes have different specific surface areas, the heat transfer mode between them and hot air will also be different. For example, fine-particle bentonite can transfer heat to the inside more quickly and is directly impacted by high-temperature air, resulting in overburning and performance degradation, which in turn leads to excessive mud content in the molding sand, reduced air permeability, poor toughness, and increased sand hole scrap rate in castings. Therefore, how to ensure the uniformity of bentonite products and the accuracy of particle size distribution is currently an urgent task.

[0003] At present, in order to ensure the uniformity of bentonite, the existing method of preparing bentonite is mostly that the operator first controls the grinding time according to the production experience, the analysis and inspection personnel take samples and test the powder products at irregular intervals, and then obtain the bentonite particle size after rough screening through a 200-mesh sieve, and then mix them, and give feedback to the operator. This method firstly increases the workload of the analysis and inspection personnel to a great extent because multiple sampling is required during the production process, and the grinding, screening, weighing and mixing steps all require conversion between different equipment, and the production efficiency is low; secondly, this method has a certain hysteresis and cannot control the production particle size in real time; more importantly, the particle size distribution of the bentonite product obtained by this method is difficult to reach a clear interval and a uniform state, and the ability to control the particle size distribution in the bentonite product is limited, which makes the quality of the mixed bentonite product uncertain, resulting in poor mixing effect, and the quality of the product produced each time cannot be guaranteed, and it will directly affect the quality and production cost of subsequent castings. Summary of the invention

[0004] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a system and method for optimizing the particle size distribution of finished bentonite products, thereby solving the problems of low production efficiency, high hysteresis, ineffective integration and unclear and uniform particle size distribution in finished bentonite products, which affect the performance of bentonite.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] A device for optimizing the particle size distribution of bentonite finished products, comprising a grinding device, a screening device, a mixing device, a control system and at least three storage bins;

[0007] The grinding equipment is used to grind the bentonite raw material into a mixed powder composed of bentonite powders of different particle sizes;

[0008] The screening device is used to separate the mixed powder according to particle size;

[0009] At least three of the storage bins are used to collect bentonite powders of different particle sizes respectively. A discharge port is provided at the bottom of the storage bin, and a weighing area is provided below each discharge port. The weighing area is used to weigh the weight of the bentonite powder delivered from the corresponding discharge port.

[0010] Each of the weighing areas is connected to the mixing device, and the mixing device is used to mix the bentonite powders of various particle sizes that have reached the standard weight after weighing to form a bentonite finished product;

[0011] The control system is communicatively connected with the grinding equipment, the screening equipment, the mixing equipment, the weighing area and at least three of the storage bins.

[0012] Furthermore, the discharge port is connected to the weighing area through a discharge pipeline, and the discharge pipeline is provided with an electric regulating valve, and the electric regulating valve is communicatively connected with the control system for controlling the bentonite powder flow rate of the discharge pipeline.

[0013] Furthermore, it is characterized in that a weighing sensor is provided at the lower part of the weighing area, and the weighing sensor is used to monitor in real time whether the weight of the bentonite powder of corresponding particle size fed into the weighing area reaches a preset value.

[0014] Furthermore, it also includes a sedimentation chamber, wherein the sedimentation chamber is provided with a grading space for grading bentonite powders of different particle sizes;

[0015] The screening device is arranged below the outlet of the grinding device and above at least three of the storage bins, and the screening device is provided with an air outlet, and the air outlet is used to spray airflow so that the mixed powder falling from the grinding device is settled in the classification space according to the particle size and enters different storage bins arranged with gradually decreasing particle sizes along the airflow direction;

[0016] The feed end of each storage bin is placed at the bottom of the sedimentation chamber;

[0017] The grinding equipment outlet, the air outlet and the feed ends of at least three of the storage bins are all in communication with the classification space.

[0018] Furthermore, a multi-stage vibration device is obliquely arranged above the storage bin, one side of the multi-stage vibration device is fixedly connected to the side wall of the sedimentation chamber, and the multi-stage vibration device includes at least three detachable screens, and the aperture of the screen corresponds to the particle size of the bentonite powder contained in the storage bin directly below;

[0019] A vibration motor is arranged on the lower surface of the multi-stage vibration device.

[0020] Furthermore, a collecting bin is provided in the settling chamber near one end of the screening device. The collecting bin is located directly below the outlet of the grinding device and is used to collect unqualified large-particle bentonite powder.

[0021] Furthermore, the collecting bin is connected to the grinding device via a return pipe, and the return pipe is used to convey unqualified large-particle bentonite powder back to the grinding device for re-grinding.

[0022] Furthermore, the feed end of the storage bin is in an inverted cone shape.

[0023] In order to achieve the above object, the present invention also adopts the following technical solutions:

[0024] A method for optimizing the particle size distribution of a bentonite product comprises the following steps:

[0025] Step S1, grinding and sieving the bentonite raw material, and using at least three storage bins to collect the bentonite powders of different particle size ranges after sieving;

[0026] Step S2, presetting the required proportion and weight requirements of the bentonite finished product, opening the discharge port of the storage bin containing the bentonite powder of the required particle size through the control system to start discharging, and quantitatively weighing the bentonite powder of each required particle size;

[0027] Step S3: Sending bentonite powders of various particle sizes reaching a preset weight into a mixing device for uniform mixing to obtain a bentonite finished product with a specific preferred particle size distribution.

[0028] Furthermore, the step S2 comprises the following steps:

[0029] Step S 21 2. Preset the proportion and weight requirements of bentonite powder of each particle size required in the bentonite finished product, open the storage bin corresponding to the required particle size through the control system according to the preset conditions to discharge the bentonite powder of each particle size into the corresponding weighing area;

[0030] Step S 22 , each weighing area determines whether the feed weight reaches the preset weight requirement of the bentonite powder of the particle size;

[0031] If so, stop discharging the corresponding storage bin.

[0032] In summary, compared with the prior art, the present invention has at least the following beneficial effects:

[0033] The invention relates to a system for optimizing the particle size distribution of a bentonite finished product, comprising a grinding device, a screening device, a mixing device, a control system and at least three storage bins; the screening device is arranged above the at least three storage bins, and is used to make the mixed powder fall into different storage bins according to the particle size after screening, so that the bentonite powder can be accurately classified according to each required particle size interval to ensure that it meets the subsequent processing requirements; at least three storage bins are respectively provided with discharge ports at the bottom, and weighing areas are correspondingly arranged below the discharge ports, so that the weight of bentonite powder of each particle size discharged from the discharge ports can be accurately measured, so as to ensure that each mixing can be accurately mixed according to the set ratio, with good consistency, and effectively ensure the production quality of the bentonite finished product during each production; the weighing area is connected with the mixing device, and the mixing device is used to mix the bentonite powder of each particle size that reaches the standard weight after weighing to form a bentonite finished product; the control system is communicatively connected with the grinding device, the screening device, the mixing device, the weighing area and at least three storage bins. Therefore, the present invention can prepare bentonite powder of multiple particle size distributions at the same time, so that bentonite powder is finely divided into clear intervals before mixing, and bentonite powder of different particle sizes can be made to realize real-time accurate control according to mass fraction and particle size distribution as required, effectively avoiding the occurrence of casting sticking sand, overburning and air permeability reduction during the subsequent use of bentonite finished product, and improving the quality control of bentonite finished product. And the production process of bentonite can be realized to be highly integrated, and it can be carried out in an orderly manner in a system during the production process, reducing the circulation loss of bentonite powder, and reducing human intervention full automation, so as to improve production efficiency. In addition, bentonite finished product can be accurately produced according to the set ratio, ensuring the consistency of bentonite finished product quality, and effectively promoting the large-scale production of bentonite.

[0034] The present invention also provides a method for optimizing the particle size distribution of a finished bentonite product corresponding to the above-mentioned device for optimizing the particle size distribution of the finished bentonite product, which has the above-mentioned beneficial effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0036] Figure 1 It is a schematic diagram of the structure of an apparatus for optimizing the particle size distribution of finished bentonite products provided in one embodiment of the present invention.

[0037] Description of reference numerals:

[0038] 1. Grinding equipment; 2. Grinding equipment export;

[0039] 2. Screening equipment;

[0040] 3. Mixing equipment;

[0041] 4. Storage bin; 41. Discharge port; 42. Discharge pipeline; 43. Electric regulating valve; 44. Feed end;

[0042] 5. Weighing area; 51. Weighing sensor;

[0043] 6. Sedimentation chamber; 61. Collection bin; 62. Return pipe; 63. Classification space; 64. Multi-stage vibration device; 641. Vibration motor. DETAILED DESCRIPTION

[0044] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0045] As attached Figure 1 As shown, a device for optimizing the particle size distribution of bentonite finished products includes a grinding device 1, a screening device 2, a mixing device 3, a control system and at least three storage bins 4;

[0046] The grinding device 1 is used to grind the bentonite raw material into a mixed powder composed of bentonite powders of different particle sizes;

[0047] The screening device 2 is used to separate the mixed powder according to the particle size;

[0048] At least three storage bins 4 are used to collect bentonite powders of different particle sizes respectively. A discharge port 41 is provided at the bottom of the storage bin 4. A weighing area 5 is provided below each discharge port 41. The weighing area 5 is used to weigh the weight of the bentonite powder delivered from the corresponding discharge port 41.

[0049] Each weighing area 5 is connected to a mixing device 3, and the mixing device 3 is used to mix the bentonite powders of various particle sizes that have reached the standard weight after weighing to form a bentonite finished product;

[0050] The control system is communicatively connected with the grinding device 1 , the screening device 2 , the mixing device 3 , the weighing area 5 and at least three storage bins 4 .

[0051] Specifically, each storage bin 4 is provided with a discharge port 41 at the bottom to facilitate the smooth discharge of bentonite powder. The weighing area 5 can accurately measure the weight of bentonite powder of each particle size discharged from the discharge port 41, ensuring that each mixing can be accurately mixed according to the set ratio and weight, effectively ensuring the production quality and consistency of the bentonite finished product during each production, and when the weighed weight reaches the weight of the bentonite of the required particle size, the weighing area 5 sends a signal to the control system to stop the corresponding storage bin 4 from continuing to discharge. Therefore, the present invention can simultaneously prepare bentonite powders of various particle size distributions, so that the bentonite powders can be finely divided into clear intervals before mixing, and bentonite powders of different particle sizes can be accurately controlled in real time according to the mass fraction and particle size distribution as needed, effectively avoiding the occurrence of sand sticking, overburning and decreased air permeability of the bentonite finished product during subsequent use, and improving the quality control of the bentonite finished product. The production process of bentonite can be highly integrated, and the production process can be carried out in an orderly manner within a system, reducing the circulation loss of bentonite powder and reducing human intervention in the entire process, thereby improving production efficiency. In addition, the finished bentonite products can be accurately produced according to the set ratio, ensuring the consistency of the quality of the finished bentonite products and effectively promoting the large-scale production of bentonite.

[0052] In certain embodiments of the present invention, the grinding equipment 1 adopts any one of a Raymond mill, a high-pressure suspension roller mill, a vertical pendulum mill, a high-pressure suspension roller mill, a high-pressure micro powder mill, a straight-through centrifugal mill, an overpressure trapezoidal mill, and a three-ring medium-speed mill.

[0053] In certain embodiments of the present invention, the screening device 2 is any one of an airflow classifier, a vibrating screen, a centrifugal separator and a cyclone separator, and most preferably, an airflow classifier is selected.

[0054] In certain embodiments of the present invention, the storage bin 4 is made of stainless steel or wear-resistant material to ensure corrosion resistance and wear resistance, while being easy to clean and maintain regularly.

[0055] In certain embodiments of the present invention, the mixing device 3 uses forced stirring to mix, and the mixing device 3 includes components such as a stirrer and a motor. The motor drives the stirrer to rotate to forcefully push and mix bentonite particles of various particle sizes, ensuring that the particles can fully contact and evenly disperse to achieve a uniform mixing effect without local accumulation. Preferably, the stirrer is selected from any one of a stirrer, a fluidized bed mixer, and a V-type mixer.

[0056] In certain embodiments of the present invention, the discharge port 41 is connected to the weighing area 5 through a discharge pipeline 42. The discharge pipeline 42 is provided with an electric regulating valve 43. The control system can accurately adjust the opening and closing degree of the electric regulating valve 43, thereby accurately controlling the flow rate of the bentonite powder in the discharge pipeline 42 to adapt to the discharge requirements of bentonite powder of different particle sizes and the adjustment of the mixing ratio of different batches of production. When the weighed weight reaches the weight of bentonite of the required particle size, the weighing area 5 sends a signal to the control system to close the electric regulating valve 43 to stop further discharge. At this time, the collection of the required weight of the bentonite particles in this particle size range is completed.

[0057] In certain embodiments of the present invention, a weighing sensor 51 is provided at the bottom of the weighing area 5, and the weighing sensor 51 is connected to the control system for real-time monitoring of the weight of the bentonite powder of the corresponding particle size fed into the weighing area 5 and feeding back the weighing information to the control system. The control system can timely determine whether the current weight reaches the customer's preset value based on the received weight data, and when the weight reaches the preset value, it can immediately control the closing of the electric regulating valve 43 to stop the discharge, so as to avoid the inaccurate weight of the bentonite powder of each particle size, which affects the use of the subsequent bentonite product. Preferably, the weighing sensor 51 is made of metal or alloy material, and is any one of a strain gauge sensor and a pressure sensor, and has a certain load-bearing capacity and anti-interference performance.

[0058] In certain embodiments of the present invention, when the screening device 2 uses an airflow classifier, due to the density difference and relative movement between the solid particles and the airflow, under the action of the gravity field, the sedimentation areas of particles of different weights are different, and the density of the solid particles is the same, so by the same token, the sedimentation areas of particles of different particle sizes are different, so that bentonite powders with different particle size distributions can be prepared according to this principle, and the high-speed airflow ejected by the airflow classifier drives the ground bentonite powder particles to move, and the bentonite powder particles are subjected to the action of multiple forces of the airflow in the airflow. The coarser bentonite powder particles have a larger inertia, and the movement trajectory in the airflow is closer to the screening device, so that they settle at a position corresponding to a larger particle size interval; the finer bentonite powder particles follow the airflow to move farther and settle at a position corresponding to a smaller particle size interval, so that the bentonite powder can be classified according to the particle size interval and distributed to different storage bins to ensure that the subsequent processing requirements are met. Preferably, the airflow temperature is 23±2°C to ensure that the structure of the bentonite powder is not destroyed. Furthermore, in order to provide a relatively stable and independent space for the screening process, the equipment for optimizing the particle size distribution of the bentonite product also includes a sedimentation chamber 6, and a grading space 63 for grading bentonite powders of different particle sizes can effectively reduce the influence of external interference factors on the screening process, so that bentonite powders of different particle sizes can be accurately settled into the corresponding storage bin 4, further improving the screening accuracy. The screening device 2 is arranged below the outlet 11 of the grinding device and above at least three storage bins 4. The screening device 2 is provided with an air outlet, which is used to spray air flow so that the mixed powder falling from the grinding device 1 is settled in the grading space 63 according to the particle size and enters different storage bins 4 arranged with gradually decreasing particle size along the air flow direction; the feed end 44 of each storage bin 4 is placed at the bottom of the sedimentation chamber 6; the grinding device outlet, the air outlet and the feed ends of at least three storage bins are all connected to the grading space, ensuring that the bentonite powder can quickly and accurately enter the storage bin 4 from the grading space 63, thereby improving the feeding efficiency and avoiding losses during transportation.

[0059] In certain embodiments of the present invention, in order to further prevent bentonite powder that does not meet the corresponding particle size range of the storage bin 4 from entering the storage bin 4, a multi-stage vibration device 64 is tilted above the storage bin 4, and one side of the multi-stage vibration device 64 is fixedly connected to the side wall of the sedimentation chamber 6. The multi-stage vibration device 64 includes at least three detachable screens, and the screen aperture corresponds to the bentonite powder particle size installed in the storage bin 4 located directly below, ensuring that the bentonite powder particle size entering the storage bin 4 meets the requirements. In addition, the detachable screen can flexibly adjust the combination of the screen according to the user's production needs, and adapt to the processing of bentonite powder with different particle size requirements. A vibration motor 641 is provided on the lower surface of the multi-stage vibration device 64, so that the bentonite powder is continuously vibrated on the screen to prevent the bentonite powder from clogging the screen holes. Furthermore, the multi-stage vibration device 64 is tilted, and the screen aperture set from bottom to top gradually decreases, so that the bentonite powder with larger particle size screened out at the top can roll down and fall into the large-aperture screen below, effectively simplifying the screening process.

[0060] In certain embodiments of the present invention, since a small amount of incompletely ground bentonite particles may be generated during the grinding process, such unqualified large-particle bentonite powder has a large inertia and its movement trajectory in the airflow tends to fall vertically under the action of gravity. Therefore, a collecting bin 61 is provided below one end of the screening device 2 in the sedimentation chamber 6. The collecting bin 61 and at least three storage bins 4 are arranged along the direction of the airflow ejected by the screening device 2, and the collecting bin 61 is located directly below the outlet 11 of the grinding device, and is used to collect the unqualified large-particle bentonite powder that is directly settled when the screening device 2 is started.

[0061] Furthermore, the collection bin 61 is connected to the grinding device 1 through a return pipe 62, and the return pipe 62 is used to transfer the unqualified large-particle bentonite powder back to the grinding device 1 for re-grinding, thereby improving the resource utilization rate of the bentonite powder and realizing recycling. Specifically, the return pipe 62 can be used to return the material by setting a fan in the pipe to blow the unqualified large-particle bentonite powder back to the grinding device 1, or by setting a screw conveyor in the pipe to transfer the unqualified large-particle bentonite powder back to the grinding device 1, or by using negative pressure suction to suck the unqualified large-particle bentonite powder back to the grinding device 1, etc. The return method is not limited here.

[0062] In certain embodiments of the present invention, the top of the feed end 44 of the storage bin 4 is in an inverted cone shape, so as to facilitate guiding the sieved bentonite powder particles to enter the storage bin 4 more smoothly.

[0063] In addition to the above-mentioned equipment for optimizing the particle size distribution of bentonite finished products, the present invention also provides a method for optimizing the particle size distribution of bentonite finished products based on the operation of the above-mentioned equipment for optimizing the particle size distribution of bentonite finished products. The method for optimizing the particle size distribution of bentonite finished products described below and the equipment for optimizing the particle size distribution of bentonite finished products described above can be referenced to each other.

[0064] A method for optimizing the particle size distribution of a bentonite product comprises the following steps:

[0065] Step S1, grinding and sieving the bentonite raw material, and using at least three storage bins 4 to collect the bentonite powders of different particle size ranges after sieving;

[0066] Step S2, preset the proportion of ingredients and weight requirements for the bentonite finished product, open the discharge port of the storage bin 4 containing the bentonite powder of the required particle size through the control system to start discharging, and quantitatively weigh the bentonite powder of each required particle size;

[0067] Step S3: Sending bentonite powders of various particle sizes reaching a preset weight into a mixing device for uniform mixing to obtain a bentonite finished product with a specific preferred particle size distribution.

[0068] This method can accurately and controllably produce bentonite powders of various particle size ratios according to customer needs, and can accurately obtain bentonite finished products that are exactly consistent with the set parameters. In addition, the production process method of bentonite can be highly integrated, and all production processes of bentonite can be carried out in an orderly manner within one system, thereby reducing the circulation loss of bentonite powder and reducing human intervention, effectively improving production efficiency, and being able to accurately produce bentonite finished products according to the set ratio, ensuring the consistency of the quality of the bentonite finished products, and effectively promoting the large-scale production of bentonite.

[0069] Specifically, step S2 includes the following steps:

[0070] Step S 21 , preset the proportion and weight requirements of bentonite powder of each particle size required in the bentonite finished product, open the storage bin 4 corresponding to the required particle size through the control system according to the preset conditions to discharge the bentonite powder of each particle size into the corresponding weighing area 5;

[0071] Step S 22 , each weighing area 5 determines whether the feed weight reaches the preset weight requirement of the bentonite powder of the particle size;

[0072] If yes, stop discharging the corresponding storage bin 4;

[0073] If not, continue discharging until the feed weight reaches the preset weight requirement of the bentonite powder of this particle size.

[0074] In order to further illustrate the technical solution of the present invention, the preferred embodiments of the present invention are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, rather than limiting the claims of the present invention.

[0075] Example 1

[0076] Step S1, sending the dried sodium bentonite to a Raymond mill for grinding to obtain bentonite powder, using an air flow classifier to sieve the bentonite powder to obtain bentonite powders in five particle size intervals of >75 μm, 65-75 μm, 44-65 μm, 37-44 μm, and <37 μm, and setting five storage bins to collect bentonite powders in each particle size interval respectively;

[0077] Step S2, according to the requirement of 85% screening rate of 200 mesh sieve for bentonite finished products in national standard GB / T 20973-2020 "Bentonite", the preset proportion of ingredients required for bentonite finished products is: the weight proportion of bentonite powder with a particle size of >75μm is 15%, the weight proportion of bentonite powder with a particle size of 65-75μm is 20%, the weight proportion of bentonite powder with a particle size of 44-65μm is 20%, the weight proportion of bentonite powder with a particle size of 37-44μm is 20%, and the weight proportion of bentonite powder with a particle size of <37μm is 25%. The discharge port of the storage bin containing bentonite powders of the above five particle size ranges is opened by the control system to start discharging, and the bentonite powders of each particle size range are sent to the corresponding weighing area. When the weight received by the weighing area reaches the preset weight of the corresponding particle size, the storage bin is stopped from discharging until the bentonite powders of the five particle sizes all reach the preset weight;

[0078] Step S3, feeding bentonite powders of five particle size intervals reaching a preset weight into a mixer respectively, and mixing the bentonite powders of the five intervals uniformly to obtain a bentonite finished product with a specific preferred particle size distribution.

[0079] Comparative Example 1

[0080] The dried sodium bentonite was sent to a Raymond mill for grinding to obtain bentonite powder. A 200-mesh sieve was used to obtain bentonite powder with two particle size ranges of >75μm and ≤75μm. According to the national standard GB / T 20973-2020 "Bentonite", the 200-mesh sieve screening rate of the finished bentonite product is 85%. The weight proportion of bentonite powder with a particle size of >75μm is 15%, and the weight proportion of bentonite powder with a particle size of ≤

[0081] The weight proportion of 75 μm bentonite powder is 85%. The bentonite powders in the above two particle size ranges are weighed manually and then sent into a mixer for stirring. The bentonite powders in the above two ranges are mixed evenly to obtain a bentonite product with a specific particle size distribution.

[0082] The bentonite products prepared in Example 1 and Comparative Example 1 are marked as Example 1 and Comparative Example 1, respectively, and then the performance of Example 1 and Comparative Example 1 is tested. The specific testing methods and test items are as follows:

[0083] (1) Test on the proportion of each particle size range of finished products

[0084] Take 500g of the bentonite finished products of Example 1 and Comparative Example 1 respectively, pour the samples into a set of sieves composed of 200 mesh, 220 mesh, 325 mesh and 400 mesh screens, load the set of sieves into a sieve shaker, shake for 10 minutes, then remove the set of sieves, start from the sieve with the largest aperture, and hand-screen the sieves of each level in order from large to small. The particles passed under the sieve are incorporated into the next level standard sieve and hand-screened together until the sieves of each level are finished. Weigh and record the mass of the residual samples of each level of sieve, calculate the weight ratio of the bentonite powder in each particle size interval, and the results are shown in Table 1.

[0085] Table 1

[0086]

[0087] The results show that the particle size interval distribution of the bentonite product obtained in Example 1 prepared by the method of the present invention is consistent with the set parameters, and the distribution of each particle size interval is relatively uniform. However, in Comparative Example 1 prepared using the existing process, due to the circulation loss and human errors between the various levels of the process, the screening rate of the 200-mesh sieve obtained is 89.3%, and the parameter value preset during preparation cannot be accurately obtained. In addition, the particles of the obtained bentonite product are relatively fine, and the powder with a particle size of less than 37 μm accounts for 49.54%, reaching an over-grinding state. In the subsequent practical application process, it is very easy to cause excessive water absorption, which can easily cause defects such as sand sticking and overburning of castings.

[0088] (2) Physical and chemical tests

[0089] According to the requirements and test methods of the national standard GB / T 20973-2020 "Bentonite", the physical and chemical properties such as blue absorption, swelling value, expansion times, wet compressive strength, hot wet tensile strength were tested respectively, and the test results are shown in Table 2. The results show that compared with Comparative Example 1, Example 1 has better performance in all aspects. The reason is that the particle size classification is accurately controlled in the bentonite finished product of Example 1, which effectively avoids the phenomenon of uneven particle size distribution and unstable product quality in the bentonite finished product. In particular, wet compressive strength is an important parameter for evaluating the wet bonding ability of bentonite. Among them, the wet compressive strength of Example 1 is 128kPa, and the wet compressive strength of Comparative Example 1 is 123kPa, indicating that the bentonite finished product of Example 1 is significantly stronger than Comparative Example 1 in the ability to resist external pressure in a saturated state, which means that in practical applications, the bentonite finished product of Example 1 can better adapt to various subsequent complex working conditions.

[0090] Table 2

[0091]

[0092] In summary, the bentonite finished product prepared using the system and method of the present invention can achieve precise control of bentonite powders of different particle sizes according to mass fraction and particle size distribution as needed, effectively avoiding sand sticking to castings, overburning and decreased air permeability during subsequent use of the bentonite finished product, and due to the process integration, the circulation loss and human error of the bentonite powder can be avoided, and the particle size range distribution in the bentonite finished product is accurately consistent with the set parameters.

[0093] The above-mentioned embodiments are only preferred embodiments of the present invention and cannot be used to limit the scope of protection of the present invention. Any non-substantial changes and substitutions made by technicians in this field on the basis of the present invention shall fall within the scope of protection required by the present invention.

Claims

1. A device for optimizing the particle size distribution of bentonite finished products, characterized in that: Includes grinding equipment, screening equipment, mixing equipment, control system and at least three storage silos; The grinding equipment is used to grind the bentonite raw material into a mixed powder composed of bentonite powders of different particle sizes; The screening device is used to separate the mixed powder according to particle size; At least three of the storage bins are used to collect bentonite powders of different particle sizes respectively. A discharge port is provided at the bottom of the storage bin, and a weighing area is provided below each discharge port. The weighing area is used to weigh the weight of the bentonite powder delivered from the corresponding discharge port. Each of the weighing areas is connected to the mixing device, and the mixing device is used to mix the bentonite powders of various particle sizes that have reached the standard weight after weighing to form a bentonite finished product; The control system is communicatively connected with the grinding equipment, the screening equipment, the mixing equipment, the weighing area and at least three of the storage bins.

2. The device according to claim 1, characterized in that The discharge port is connected to the weighing area through a discharge pipeline. The discharge pipeline is provided with an electric regulating valve. The electric regulating valve is communicatively connected with the control system and is used to control the bentonite powder flow rate of the discharge pipeline.

3. The device according to claim 1, characterized in that A weighing sensor is provided at the lower part of the weighing area, and the weighing sensor is used to monitor in real time whether the weight of the bentonite powder of corresponding particle size fed into the weighing area reaches a preset value.

4. The device according to claim 1, characterized in that It also includes a sedimentation chamber, wherein the sedimentation chamber is provided with a grading space for grading bentonite powders of different particle sizes; The screening device is arranged below the outlet of the grinding device and above at least three of the storage bins, and the screening device is provided with an air outlet, and the air outlet is used to spray airflow so that the mixed powder falling from the grinding device is settled in the classification space according to the particle size and enters different storage bins arranged with gradually decreasing particle sizes along the airflow direction; The feed end of each storage bin is placed at the bottom of the sedimentation chamber; The grinding equipment outlet, the air outlet and the feed ends of at least three of the storage bins are all in communication with the classification space.

5. The device according to claim 4, characterized in that A multi-stage vibration device is obliquely arranged above the storage bin, one side of the multi-stage vibration device is fixedly connected to the side wall of the sedimentation chamber, and the multi-stage vibration device includes at least three detachable screens, and the aperture of the screen corresponds to the particle size of the bentonite powder contained in the storage bin directly below; A vibration motor is arranged on the lower surface of the multi-stage vibration device.

6. The device according to claim 5, characterized in that A collecting bin is provided in the settling chamber near one end of the screening device. The collecting bin is located directly below the outlet of the grinding device and is used to collect unqualified large-particle bentonite powder.

7. The device according to claim 6, characterized in that The collecting bin is connected to the grinding device via a return pipe, and the return pipe is used to convey unqualified large-particle bentonite powder back to the grinding device for re-grinding.

8. The device according to claim 1, characterized in that The feeding end of the storage bin is in an inverted cone shape.

9. A method for optimizing the particle size distribution of a bentonite product, characterized in that: The following steps are involved: Step S1, grinding and sieving the bentonite raw material, and using at least three storage bins to collect the bentonite powders of different particle size ranges after sieving; Step S2, presetting the required proportion and weight requirements of the bentonite finished product, opening the discharge port of the storage bin containing the bentonite powder of the required particle size through the control system to start discharging, and quantitatively weighing the bentonite powder of each required particle size; Step S3: Sending bentonite powders of various particle sizes reaching a preset weight into a mixing device for uniform mixing to obtain a bentonite finished product with a specific preferred particle size distribution.

10. The method according to claim 9, characterized in that The step S2 comprises the following steps: Step S 21 2. Preset the proportion and weight requirements of bentonite powder of each particle size required in the bentonite finished product, open the storage bin corresponding to the required particle size through the control system according to the preset conditions to discharge the bentonite powder of each particle size into the corresponding weighing area; Step S 22 , each weighing area determines whether the feed weight reaches the preset weight requirement of the bentonite powder of the particle size; If so, stop discharging the corresponding storage bin.

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