Process for the production of ultrafine calcium carbonate

Abstract

A production process of superfine calcium carbonate, small pieces of material are sent into the superfine grinding equipment for gradient grinding, the grinding equipment includes a box, first grinding assembly and second grinding assembly with same structure are arranged in the box, the first grinding assembly includes a grinding disc and a grinding roller, the outer periphery of the grinding disc is fixedly connected with the inner wall of the box, the grinding roller is rotatably arranged in the grinding disc, a cavity is formed in the grinding roller, inert gas is filled in the cavity, an installation cavity is formed in the grinding roller and is communicated with the cavity, a sliding plate is slidably arranged in the installation cavity, an air inlet plate is coaxially arranged above the grinding roller, an accommodating cavity is formed in the air inlet plate, air injection holes are uniformly formed in the bottom of the air inlet plate and are communicated with the accommodating cavity, conical stoppers are movably arranged in the air injection holes, a moving plate is slidably arranged in the accommodating cavity and is fixedly connected with the stoppers, a top rod is fixedly arranged on the top of the sliding plate, the top rod extends into the accommodating cavity and is fixedly connected with the moving plate, and the real-time heat dissipation load can be matched.

Description

Technical Field

[0001] This invention relates to the field of ultrafine calcium carbonate technology, and specifically to a production process for ultrafine calcium carbonate. Background Technology

[0002] Ultrafine calcium carbonate is a widely used inorganic non-metallic powder filler with advantages such as high whiteness, low hardness, good chemical stability, and high cost-effectiveness. It is extensively used in many industries, including plastics, rubber, coatings, inks, papermaking, and adhesives. Currently, the industrial production of ultrafine calcium carbonate is mainly divided into two categories: chemical carbonation and physical grinding. Among them, the physical grinding method relies on the processing of high-purity calcite ore and has advantages such as readily available raw materials, simple process, large production capacity, low cost, and no pollution from waste gas, wastewater, and solid waste, making it the mainstream production method for ultrafine calcium carbonate.

[0003] For example, patent document CN118080130A, entitled "A Calcium Carbonate Grinding Device," describes a grinding device for producing ultrafine calcium carbonate powder. The device includes a main body, a base plate fixedly connected to the right side of the main body, a discharge port fixedly connected to the side of the main body away from the base plate, a feed port fixedly connected to the top of the main body, a fixed column fixedly connected to the inner bottom wall of the main body, a motor fixedly connected to the inner bottom wall of the main body, and a feed hopper fixedly connected to the inside of the top of the main body. It also includes a cooling mechanism, comprising a cooling box fixedly connected to the top of the base plate, a filter screen inserted inside the cooling box, a horizontal plate fixedly connected inside the cooling box, and several semiconductor cooling plates fixedly connected inside the cooling box, the semiconductor cooling plates being evenly distributed. Cold air can be intermittently introduced into the main body through the cooling mechanism to reduce the temperature inside the main body.

[0004] However, in the above literature, the heat generation rate of the grinding roller changes in real time due to fluctuations in the feed rate and changes in the hardness of the material during the grinding process. The intermittent supply of cold air cannot meet the real-time heat generation requirements of the grinding roller and is difficult to match the actual heat dissipation load. This can easily lead to insufficient or excessive cooling, resulting in large temperature fluctuations in the grinding chamber and poor cooling control, which in turn affects the processing quality of ultrafine calcium carbonate powder. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of existing technologies by proposing a production process for ultrafine calcium carbonate, which solves the technical problems mentioned in the background art, such as the tendency for insufficient or excessive cooling, resulting in large temperature fluctuations within the grinding chamber and poor cooling control.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: A process for producing ultrafine calcium carbonate includes the following steps: S1. Raw material pretreatment: Select high-purity calcium carbonate raw ore, remove impurities such as mud, sand, quartz and mica by screening, and crush the purified raw ore to obtain small pieces of calcium carbonate material. S2. Grinding: The small pieces of material are fed into an ultrafine grinding equipment for gradient grinding. The small pieces of material are ultrafinely ground, dissociated and shaped to obtain ultrafine calcium carbonate powder. S3. Surface modification: The ultrafine calcium carbonate powder is fed to a high-speed dry modification machine. Under high temperature and high speed stirring, the powder modifier is added evenly so that the modifier is evenly coated on the surface of the calcium carbonate particles, thus completing the hydrophobic activation modification of the powder. S4. Finished product processing: The modified powder is subjected to negative pressure dust removal, low-speed dispersing and deagglomeration, and sieving to remove a small amount of agglomerated particles and impurities generated during the modification and grinding process, and finally the ultrafine calcium carbonate product is obtained.

[0007] Furthermore, the grinding equipment in S2 includes a housing, and a first grinding component and a second grinding component with the same structure are spaced apart inside the housing. The first grinding component includes a grinding disc and a grinding roller. The outer periphery of the grinding disc is fixedly connected to the inner wall of the housing. The grinding roller is rotatably disposed inside the grinding disc, and a grinding gap that gradually narrows from top to bottom is formed between the grinding roller and the grinding disc. The housing is provided with a drive component for driving the grinding roller to rotate. The grinding roller has an internal cavity filled with inert gas. An installation cavity connected to the internal cavity is also present in the grinding roller. A sliding plate is slidably mounted within the installation cavity. An air inlet plate is coaxially mounted above the grinding roller, and an internal receiving cavity is provided within the air inlet plate. Air jet holes communicating with the receiving cavity are evenly distributed at the bottom of the air inlet plate. Conical sealing plugs for blocking the air jet holes are movably mounted within the air jet holes. A movable plate is slidably mounted within the receiving cavity and is fixedly connected to the sealing plug. A top rod is fixedly mounted on the top of the sliding plate, extending into the receiving cavity and fixedly connected to the movable plate. A cooling assembly that supplies cold air to the receiving cavity is also provided on the housing.

[0008] Furthermore, multiple elastic flaps are fixedly arranged around the bottom of the jet hole in a circumferential manner. The elastic flaps are arc-shaped structures that are wider at the top and narrower at the bottom. A transmission component is provided inside the jet hole. The transmission component is used to drive the multiple elastic flaps to close together to form a trumpet-shaped structure with a narrow opening at the bottom.

[0009] Furthermore, the transmission assembly includes a bracket fixedly installed inside the jet hole and a telescopic rod slidably installed at the center of the bracket. Multiple hinge rods are hingedly installed at the bottom of the telescopic rod, the other end of the hinge rod is hingedly connected to the corresponding elastic flap, and the top of the telescopic rod is fixedly connected to the corresponding sealing plug.

[0010] Furthermore, a fan wheel is rotatably mounted on the top of the grinding roller.

[0011] Furthermore, a scraper that is fixedly installed on the impeller and fits against the top surface of the grinding roller is provided.

[0012] Furthermore, the drive assembly includes a motor fixedly mounted at the bottom of the housing and a rotating shaft rotatably mounted inside the housing. The grinding roller is fixedly sleeved on the outer circumference of the rotating shaft. A drive gear is fixedly mounted at the output end of the motor, and a driven gear is fixedly sleeved on the outer circumference of the rotating shaft. The driven gear meshes with the drive gear.

[0013] Furthermore, the rotating shaft has an air inlet channel along the axial direction, and an air inlet pipe is rotatably installed on the top of the rotating shaft. The air inlet pipe is connected to the cooling component. The inner wall of the air inlet channel has a vent hole that communicates with the receiving cavity. The moving plate has evenly distributed connecting holes.

[0014] Furthermore, the top of the box is provided with a feed hopper that communicates with its interior, the bottom of the box is fixed with an inclined guide plate, and a discharge port is opened on one side of the bottom of the box.

[0015] Furthermore, a first spring is fixedly installed between the movable plate and the inner wall of the mounting cavity.

[0016] Furthermore, the gap size at the bottom of the grinding gap of the first grinding component is larger than the gap size at the top of the second grinding gap.

[0017] The beneficial effects of this invention are as follows: By filling the cavity of the grinding roller with inert gas and incorporating a sliding plate, an air inlet plate, a conical sealing plug, a moving plate, and a push rod, heat is continuously generated during the grinding of calcium carbonate through friction between the grinding roller and the calcium carbonate material. As the temperature of the grinding roller rises, the inert gas in its internal cavity expands due to heat, increasing the gas pressure. This, in turn, pushes the sliding plate within the mounting cavity upwards. The sliding plate, via the push rod, drives the moving plate within the receiving cavity to move upwards simultaneously. The moving plate then causes the conical sealing plug to gradually detach from the air jet orifice. Because the sealing plug has a conical structure, the cross-sectional area of ​​the air jet orifice gradually increases linearly during its upward movement, and the cold gas flow rate increases linearly accordingly. This adapts to the gradually increasing heat generation rate of the grinding roller and matches the real-time heat dissipation load, effectively avoiding the problems of insufficient or excessive cooling caused by intermittent cooling in traditional equipment. This reduces the temperature fluctuation range inside the grinding chamber, improves the accuracy of cooling control, and ensures the stability of the physicochemical properties of the calcium carbonate material during the grinding process. Attached Figure Description

[0018] Figure 1 This is a perspective view of the present invention; Figure 2 This is a bottom sectional view of the present invention; Figure 3 This is a cross-sectional view of the present invention; Figure 4 For the present invention Figure 3 Enlarged view of point A; Figure 5 For the present invention Figure 4Enlarged view of point B; Figure 6 This is a perspective view of the air inlet plate and grinding assembly of the present invention.

[0019] Explanation of reference numerals in the attached drawings: 1. Housing; 2. Feed hopper; 3. Guide plate; 4. Grinding disc; 5. Grinding roller; 6. Motor; 7. Rotating shaft; 8. Drive gear; 9. Driven gear; 10. Cavity; 11. Mounting cavity; 12. Slide plate; 13. Air inlet plate; 14. Receiving cavity; 15. Air jet hole; 16. Sealing plug; 17. Moving plate; 18. Top rod; 19. First spring; 20. Cooling assembly; 21. Air inlet channel; 22. Air inlet pipe; 23. Vent hole; 24. Connecting hole; 25. Elastic flap; 26. Movable rod; 27. Sliding rod; 28. Limiting groove; 29. ​​Limiting block; 30. Hinge rod; 31. Second spring; 32. Fan wheel; 33. Scraper. Detailed Implementation

[0020] The technical solutions of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0021] A process for producing ultrafine calcium carbonate includes the following steps: S1. Raw material pretreatment: Select high-purity calcium carbonate raw ore, remove impurities such as mud, sand, quartz and mica by screening, and crush the purified raw ore to obtain small pieces of calcium carbonate material. S2. Grinding: The small pieces of material are fed into an ultrafine grinding equipment for gradient grinding. The small pieces of material are ultrafinely ground, dissociated and shaped to obtain ultrafine calcium carbonate powder. S3. Surface modification: The ultrafine calcium carbonate powder is fed to a high-speed dry modification machine. Under high temperature and high speed stirring, the powder modifier is added evenly so that the modifier is evenly coated on the surface of the calcium carbonate particles, thus completing the hydrophobic activation modification of the powder. S4. Finished product processing: The modified powder is subjected to negative pressure dust removal, low-speed dispersing and deagglomeration, and sieving to remove a small amount of agglomerated particles and impurities generated during the modification and grinding process, and finally the ultrafine calcium carbonate product is obtained.

[0022] like Figures 1-6 As shown, the grinding equipment in S2 includes a housing 1, which is an integral structure with a cylindrical upper part and a cubic lower part. A feed hopper 2, connected to the interior of the housing 1, is fixedly installed on the top of the housing 1 for feeding calcium carbonate fragments into the housing 1. An inclined guide plate 3 is fixedly installed on the bottom of the housing 1, and a discharge port is provided on one side of the bottom of the housing 1 to facilitate the smooth discharge of the ground powder and prevent material accumulation and residue.

[0023] Inside the housing 1, two identical grinding components are installed at intervals to achieve stepwise gradient grinding of calcium carbonate material, improving the fineness and uniformity of the powder. The first grinding component includes a grinding disc 4 and a grinding roller 5. The outer periphery of the grinding disc 4 is fixedly connected to the inner wall of the housing 1, and the grinding roller 5 is rotatably installed inside the grinding disc 4. Both are arranged coaxially, forming a grinding gap that gradually narrows from top to bottom between the grinding roller 5 and the grinding disc 4. The material is subjected to compression, grinding, and shearing within the gap, gradually being ground into ultrafine powder. The bottom gap size of the grinding gap of the first grinding component is larger than the top gap size of the grinding gap of the second grinding component, which facilitates the smooth entry of particles ground by the first grinding component into the grinding gap of the second grinding component, while avoiding problems such as insufficient grinding and uneven particle size caused by excessive grinding pressure in a single grinding cycle.

[0024] A drive assembly for rotating the grinding roller 5 is installed on the housing 1. The drive assembly includes a motor 6 fixedly mounted at the bottom of the housing 1 and a rotating shaft 7 rotatably mounted inside the housing 1. The two ends of the rotating shaft 7 are respectively rotatably inserted through the center of the top wall and the center of the bottom wall of the housing 1. The grinding roller 5 is fixedly sleeved on the outer circumference of the rotating shaft 7 and can rotate synchronously with the rotating shaft 7. A drive gear 8 is fixedly mounted on the output end of the motor 6, and a driven gear 9 is fixedly sleeved on the outer circumference of the rotating shaft 7. The driven gear 9 meshes with the drive gear 8. When the motor 6 is working, the drive gear 8 drives the driven gear 9 to rotate, the driven gear 9 drives the rotating shaft 7 to rotate, and the rotating shaft 7 drives the grinding roller 5 to rotate, thereby realizing the grinding operation of the material.

[0025] The grinding roller 5 has a sealed cavity 10 inside, which is filled with an inert gas. The inert gas can be any one of helium, argon, or neon. It has stable chemical properties and good thermal expansion and contraction characteristics, and can expand in volume in response to temperature changes of the grinding roller 5. The grinding roller 5 also has a mounting cavity 11 that communicates with the cavity 10. A sliding plate 12 is slidably mounted in the mounting cavity 11. The sliding plate 12 is slidably sleeved on the outer circumference of the rotating shaft 7. The sliding parts of the sliding plate 12, the rotating shaft 7, and the mounting cavity 11 are all sealed.

[0026] An air inlet plate 13 is coaxially mounted above the grinding roller 5, and is fixedly sleeved on the outer circumference of the rotating shaft 7. An accommodating cavity 14 is formed inside the air inlet plate 13, and jet holes 15, communicating with the accommodating cavity 14, are evenly distributed at the bottom of the air inlet plate 13, facing the grinding roller 5. A conical sealing plug 16 is movably disposed within the jet holes 15 for sealing and adjusting the flow of the jet holes 15. A movable plate 17 is slidably disposed within the accommodating cavity 14, and is fixedly connected to the sealing plug 16. Multiple push rods 18 are fixedly mounted circumferentially on the top of the slide plate 12. The push rods 18 slide upwards sequentially through the grinding roller 5 and the air inlet plate 13, and extend into the accommodating cavity 14 to be fixedly connected to the bottom surface of the movable plate 17. Simultaneously, a first spring 19 is fixedly installed between the movable plate 17 and the bottom wall of the mounting cavity 11. The first spring 19 is sleeved on the outer circumference of the rotating shaft 7 and can reset the slide plate 12.

[0027] The housing 1 is also equipped with a cooling assembly 20 that supplies cold air to the receiving cavity 14. An air inlet channel 21 is axially formed on the rotating shaft 7, and an air inlet pipe 22 is rotatably mounted on the top of the rotating shaft 7 via a rotary joint. The air inlet pipe 22 is connected to the cold air output end of the cooling assembly 20. A vent hole 23 is formed on the inner wall of the air inlet channel 21, communicating with the receiving cavity 14 of the air inlet plate 13, so that the cold air output by the cooling assembly 20 can be stably delivered to the inside of the receiving cavity 14. Simultaneously, several connecting holes 24 are evenly formed on the moving plate 17. During the up-and-down movement of the moving plate 17, cold air can flow through the connecting holes 24 to the lower side of the moving plate 17 and smoothly enter each jet hole 15, achieving uniform jet cooling. The cooling assembly 20 is prior art and can be the same as the cooling mechanism in a calcium carbonate grinding device in Chinese Patent No. CN118080130A. Its specific structure and working principle will not be described in detail here.

[0028] During the grinding of calcium carbonate, the grinding roller 5 continuously rubs against the calcium carbonate material, generating heat. As the temperature of the grinding roller 5 rises, the inert gas in its internal cavity 10 expands due to the heat, increasing the gas pressure and pushing the sliding plate 12 in the mounting cavity 11 upward. The sliding plate 12 drives the moving plate 17 in the receiving cavity 14 to move upward synchronously via the push rod 18. The moving plate 17 drives the conical sealing plug 16 to gradually disengage from the air jet hole 15. Because the sealing plug 16 adopts a conical structure, the conduction cross-sectional area of ​​the air jet hole 15 gradually increases linearly during its upward movement, and the cold gas ejection flow rate increases linearly in sync. This can adapt to the gradually increasing heat generation rate of the grinding roller 5, match the real-time heat dissipation load, and effectively avoid the problems of insufficient or excessive cooling caused by the intermittent cooling of traditional equipment. This reduces the temperature fluctuation range inside the grinding cavity, improves the accuracy of cooling control, and ensures the stability of the physicochemical properties of the calcium carbonate material during the grinding process.

[0029] To further optimize cooling and heat dissipation, multiple elastic flaps 25 are uniformly fixedly installed around the bottom of the jet nozzle 15. The elastic flaps 25 are made of rubber and have the ability to deform and return to their original position. The elastic flaps 25 have an arc-shaped cross-section structure that is wider at the top and narrower at the bottom. A transmission component is installed inside the jet nozzle 15. The transmission component is used to drive the multiple elastic flaps 25 to close together, forming a trumpet-shaped structure with a narrow opening at the bottom, so as to accelerate the jet of cold air, increase the airflow rate of cold air, and accelerate the heat dissipation efficiency of the grinding roller 5.

[0030] The transmission assembly includes a bracket fixedly installed within the jet port 15 and a telescopic rod slidably installed at the center of the bracket. The telescopic rod includes a movable rod 26 and a sliding rod 27. The movable rod 26 is vertically slidable along the center of the bracket, and a limiting groove 28 is formed axially inside the movable rod 26. The sliding rod 27 is slidably fitted inside the limiting groove 28. A limiting block 29 that slides in cooperation with the limiting groove 28 is fixedly installed at the bottom of the sliding rod 27. The top of the sliding rod 27 extends to the outside of the movable rod 26 and is fixedly connected to the conical sealing plug 16. Multiple hinge rods 30 are hinged to the bottom of the movable rod 26, and the other ends of the multiple hinge rods 30 are respectively hinged to the inner side of the elastic flap 25 at corresponding positions. A second spring 31 is sleeved on the outer periphery of the movable rod 26. The two ends of the second spring 31 are fixedly connected to the bracket and the bottom flange of the movable rod 26, respectively, for realizing the reset of the movable rod 26.

[0031] During continuous grinding, when the sealing plug 16 completely disengages from the jet hole 15, the sealing plug 16 drives the sliding rod 27 upward. The limiting block 29 at the bottom of the sliding rod 27 abuts against the top wall of the limiting groove 28, at which point the cold air jet flow rate reaches its maximum value. If the feed rate further increases or the material hardness increases, the friction intensity between the grinding roller 5 and the calcium carbonate material increases, the heat generation rate accelerates significantly, and the expansion degree of the inert gas in the cavity 10 of the grinding roller 5 further increases, continuously pushing the sliding plate 12, the push rod 18, and the moving plate 17 and sealing plug 16 upward. The sealing plug 16 can continue to drive the sliding rod 27 upward, and the limiting block 29 abuts against the transmission drive to make the movable rod 26 slide upward synchronously. As the movable rod 26 moves upward, it pulls the multiple hinged rods 30 at the bottom to rotate upward simultaneously. This, in turn, pulls the multiple circumferentially distributed elastic petals 25 to bend inward and close, forming a narrow-mouth horn structure at the bottom of the air jet 15. Utilizing the fluid constriction acceleration effect, this significantly increases the velocity of the cold air jet. The high-speed cold air directly impacts the surface of the grinding roller 5, achieving rapid cooling of the grinding roller 5 and meeting the heat dissipation requirements of high-load grinding conditions. Simultaneously, the high-speed cold air flows downward along the grinding gap, actively driving the ground fine powder downwards for effective powder discharge. A fan wheel 32 is rotatably mounted on the top of the grinding roller 5. The fan wheel 32 includes a rotating ring and fan blades. The rotating ring is rotatably sleeved on the top of the grinding roller 5 via bearings. Fan blades are evenly fixedly mounted on the outer circumference of the rotating ring. The fan blades are arranged at an angle and have a gap with the top surface of the grinding roller 5 to facilitate the synchronous rotation of the rotating ring after the fan blades are impacted by the wind. When high-speed cold air is ejected from the jet hole 15, the high-speed airflow can blow the fan wheel 32 to rotate continuously. During the rotation of the fan wheel 32, turbulent airflow is generated, which disturbs the thermal boundary layer on the surface of the grinding roller 5, breaks the static heat insulation film, accelerates the convection and diffusion of hot air on the surface of the grinding roller 5, and further improves the overall heat dissipation efficiency of the grinding roller 5.

[0032] When the feed rate increases, more dust or irregularly shaped particles will be generated and remain on the top surface of the grinding roller 5. Therefore, at least one fan blade of the impeller 32 is fixedly installed at the bottom with a scraper 33 that is in close contact with the top surface of the grinding roller 5. When the impeller 32 rotates with the high-speed airflow, it drives the scraper 33 to make a circular motion along the top surface of the grinding roller 5, which can scrape off the calcium carbonate fragments and dust that remain on the top surface of the grinding roller 5, thus avoiding the accumulation of dust fragments covering the surface of the grinding roller 5, which would lead to heat dissipation obstruction and heat exchange efficiency reduction.

[0033] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A production process for ultrafine calcium carbonate, characterized in that, Includes the following steps: S1. Raw material pretreatment: Select high-purity calcium carbonate raw ore, remove impurities such as mud, sand, quartz and mica by screening, and crush the purified raw ore to obtain small pieces of calcium carbonate material. S2. Grinding: The small pieces of material are fed into an ultrafine grinding equipment for gradient grinding, and the small pieces of material are ultrafinely ground, dissociated and shaped to obtain ultrafine calcium carbonate powder. S3. Surface modification: The ultrafine calcium carbonate powder is fed to a high-speed dry modification machine. Under high temperature and high speed stirring, the powder modifier is added evenly so that the modifier is evenly coated on the surface of the calcium carbonate particles, thus completing the hydrophobic activation modification of the powder. S4. Finished product processing: The modified powder is subjected to negative pressure dust removal, low-speed dispersing and deagglomeration, and sieving to remove a small amount of agglomerated particles and impurities generated during the modification and grinding process, and finally the ultrafine calcium carbonate product is obtained.

2. A production process for ultrafine calcium carbonate, as described in claim 1, characterized in that, The grinding equipment in S2 includes a housing (1), and a first grinding component and a second grinding component with the same structure are arranged at intervals inside the housing (1). The first grinding component includes a grinding disc (4) and a grinding roller (5). The outer periphery of the grinding disc (4) is fixedly connected to the inner wall of the housing (1). The grinding roller (5) is rotatably arranged inside the grinding disc (4). A grinding gap that gradually narrows from top to bottom is formed between the grinding roller (5) and the grinding disc (4). The housing (1) is provided with a driving component for driving the grinding roller (5) to rotate. The grinding roller (5) has a cavity (10) inside, which is filled with inert gas. The grinding roller (5) also has a mounting cavity (11) connected to the cavity (10). A sliding plate (12) is slidably mounted in the mounting cavity (11). An air inlet plate (13) is coaxially arranged above the grinding roller (5). The air inlet plate (13) has a receiving cavity (14) inside. Air jet holes (15) are evenly distributed at the bottom of the air inlet plate (13) and communicate with the receiving cavity (14). A conical sealing plug (16) for sealing the air vent (15) is movably arranged inside the vent (15). A movable plate (17) is slidably arranged inside the receiving cavity (14). The movable plate (17) is fixedly connected to the sealing plug (16). A top rod (18) is fixedly arranged on the top of the sliding plate (12). The top rod (18) extends into the receiving cavity (14) and is fixedly connected to the movable plate (17). A cooling assembly (20) for supplying cold air to the receiving cavity (14) is also provided on the housing (1).

3. The production process of ultrafine calcium carbonate according to claim 1, characterized in that, The bottom of the jet hole (15) is fixedly provided with multiple elastic petals (25) around its circumference. The elastic petals (25) are arc-shaped structures that are wider at the top and narrower at the bottom. A transmission component is provided inside the jet hole (15). The transmission component is used to drive the multiple elastic petals (25) to close together to form a trumpet-shaped structure with a narrow bottom.

4. The production process of ultrafine calcium carbonate according to claim 3, characterized in that, The transmission assembly includes a bracket fixedly installed in the jet hole (15) and a telescopic rod slidably installed in the center of the bracket. Multiple hinge rods (30) are hingedly installed at the bottom of the telescopic rod. The other end of the hinge rod (30) is hingedly connected to the corresponding elastic flap (25). The top of the telescopic rod is fixedly connected to the corresponding sealing plug (16).

5. The production process of ultrafine calcium carbonate according to claim 4, characterized in that, The top of the grinding roller (5) is rotatably equipped with a fan wheel (32).

6. The production process of ultrafine calcium carbonate according to claim 5, characterized in that, The impeller (32) is fixedly provided with a scraper (33) that is in contact with the top surface of the grinding roller (5).

7. The production process of ultrafine calcium carbonate according to claim 1, characterized in that, The drive assembly includes a motor (6) fixedly installed at the bottom of the housing (1) and a rotating shaft (7) rotatably installed inside the housing (1). The grinding roller (5) is fixedly sleeved on the outer circumference of the rotating shaft (7). The output end of the motor (6) is fixedly provided with a drive gear (8). The outer circumference of the rotating shaft (7) is fixedly sleeved with a driven gear (9). The driven gear (9) meshes with the drive gear (8).

8. The production process of ultrafine calcium carbonate according to claim 7, characterized in that, The rotating shaft (7) has an air inlet channel (21) along the axial direction. An air inlet pipe (22) is rotatably provided on the top of the rotating shaft (7). The air inlet pipe (22) is connected to the cooling component (20). A vent hole (23) connected to the receiving cavity (14) is provided on the inner wall of the air inlet channel (21). A connecting hole (24) is evenly provided on the moving plate (17).

9. The production process of ultrafine calcium carbonate according to claim 1, characterized in that, The top of the box (1) is provided with a feeding hopper (2) that is connected to its interior, the bottom of the box (1) is fixed with an inclined guide plate (3), and the bottom side of the box (1) is provided with a discharge port.

10. The production process of ultrafine calcium carbonate according to claim 1, characterized in that, A first spring (19) is fixedly installed between the movable plate (17) and the inner wall of the mounting cavity (11).

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