Process and apparatus for the production of heavy calcium carbonate

Abstract

The application belongs to the technical field of calcium carbonate preparation, and discloses a heavy calcium carbonate preparation method and equipment, which comprises support legs, the top end of the support legs is fixed with a crushing mechanism, one end of the crushing mechanism is provided with a support frame, one end of the crushing mechanism is provided with a grinding cylinder, the outside of the support frame is fixed with a grinding mechanism, one end of the support frame is fixed with a discharge pipe, the bottom end of the discharge pipe is provided with a screening box, the inside of the screening box is installed with a screening mechanism, and one end of the screening box is provided with a limiting mechanism. Through the cooperation of the second servo motor, the first connecting rod, the transmission gear and other structures, the device can efficiently grind raw materials. The second servo motor drives the first connecting rod and the transmission gear to rotate, the transmission gear is engaged with the tooth block outside the grinding cylinder, so as to drive the grinding cylinder to rotate. Combined with the zirconium oxide balls and the grinding blocks inside, the raw materials can be ground to the required fine degree under the condition that the ball-material ratio is 8-10:1, and the grinding efficiency and effect are improved.

Description

Technical Field

[0001] This invention belongs to the field of calcium carbonate preparation technology, specifically a method and equipment for preparing heavy calcium carbonate. Background Technology

[0002] Heavy calcium carbonate, as an important inorganic non-metallic mineral filler, is widely used in plastics, rubber, coatings, papermaking and other fields. Its performance directly affects the quality of downstream products. In industrial production, heavy calcium carbonate is usually prepared from natural minerals such as calcite and marble through processes such as crushing, grinding, grading and modification.

[0003] In existing technologies, the preparation process of heavy calcium carbonate generally includes steps such as raw material crushing, mechanical grinding, drying, and surface treatment. For example, in the crushing stage, single-roll or double-roll crushers are often used for coarse crushing, but their crushing efficiency is low and the particle size distribution of the crushed material is wide. In the grinding process, steel balls or ceramic balls are often used as grinding media. Improper control of the ball-to-material ratio can easily lead to over-grinding or uneven particle size. At the same time, the selection and addition ratio of grinding aids will also affect the grinding efficiency and product purity.

[0004] In practical applications, the aforementioned existing technologies suffer from low surface activity of the crushed raw materials, making subsequent grinding and modification difficult and affecting product dispersibility. Furthermore, the materials tend to agglomerate during the grinding process, leading to a decrease in grinding efficiency. Therefore, it is necessary to optimize the crushing process, introduce low-temperature plasma activation, improve the synergistic mechanism of grinding and sieving, and adopt vacuum freeze-drying and precise crystal form control and surface modification technologies. This provides a method and dedicated equipment for preparing high-purity, fine-grained, well-dispersible, and highly stable heavy calcium carbonate. Summary of the Invention

[0005] To address the problems mentioned in the background section, this invention provides a method and apparatus for preparing heavy calcium carbonate.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a method for preparing heavy calcium carbonate, comprising the following steps: S1. Select calcite and marble minerals with a calcium carbonate content ≥98%, clean them, add them to the inside of the crushing box for coarse crushing to 2-5cm, and after crushing, place them in a low-temperature plasma reaction device and apply a voltage of 10-15kV for 5-10 minutes in a mixed gas atmosphere of argon 10-15L / min and oxygen 0.5-1L / min. S2. The activated raw material, along with 0.5%-1% of polyether-type grinding aid and 1%-2% of organic-inorganic hybrid modifier, is added into the grinding cylinder through the opening at the top of the feed pipe for grinding. The ball-to-material ratio of zirconia balls inside the grinding cylinder is 8-10:1. The ground material is then conveyed to the top of the screening box for sieving, allowing particles of the required size to pass through the screening screen. Fine particles with d97≤2μm are collected, while coarse particles are returned to the grinding cylinder for further grinding, ensuring a uniform particle size distribution in the product. S3. After classification, the heavy calcium carbonate slurry with a solid content of 30%-40% is sprayed into liquid nitrogen at -30℃--40℃ through a high-pressure nozzle of 10-15MPa and instantly frozen into tiny particles. Then, it is transferred to a vacuum freeze-drying equipment and sublimated and dried at a vacuum of 10-20Pa and -20℃--10℃ to maintain the particle dispersion and fine particle size. S4. The dried particles are placed in a high-pressure reactor, and 0.05-0.1 mol / L of a mixed crystal form regulator of sodium citrate and diammonium hydrogen phosphate is added. The mixture is reacted at 80-120℃ and 2-3 MPa for 1-2 hours to form a stable and regular crystal structure. The heavy calcium carbonate product is then placed in a fluidized bed reactor, and long-chain alkyl organosilicon compound vapor is introduced at 50-80℃. The reaction is carried out for 1-2 hours to form a protective film on the product surface.

[0007] The present invention also provides a heavy calcium carbonate preparation device, including a support leg, a crushing mechanism fixed at the top of the support leg, a support frame provided at one end of the crushing mechanism, a grinding cylinder provided at one end of the crushing mechanism, a grinding mechanism fixed outside the support frame, a discharge pipe fixed at one end of the support frame, a screening box provided at the bottom end of the discharge pipe, a screening mechanism installed inside the screening box, and a limit mechanism provided at one end of the screening box; The crushing mechanism includes a mounting frame, a first servo motor, and a crushing roller. The mounting frame is fixed to the top of the support leg, the top of the mounting frame is fixed with the first servo motor, the rotating end of the first servo motor is fixed with the crushing roller, and the top of the mounting frame is fixed with a crushing box. The grinding mechanism includes a second servo motor, a first connecting rod, and a transmission gear. The second servo motor is fixed to the outside of the support frame, the rotating end of the second servo motor is fixed to the first connecting rod, the outside of the first connecting rod is fixed to the transmission gear, and the outside of the grinding cylinder is fixed to a toothed block.

[0008] Preferably, one end of the crushing box is provided with a discharge port, one end of the discharge port is fixed with a guide plate, the bottom end of the guide plate is connected to a feed pipe, and one end of the feed pipe is equipped with a fan.

[0009] Preferably, there are two sets of the first servo motor and the breaking roller, and the first servo motor and the breaking roller are symmetrically distributed about the central axis of the crushing box. A support frame is fixed to the outside of the feed pipe, and a grinding cylinder is rotatably connected to the outside of the feed pipe.

[0010] Preferably, the grinding cylinder is provided with zirconia balls inside, the grinding cylinder is fixed with grinding blocks inside, and the transmission gears are provided in two sets, which are symmetrically distributed about the central axis of the support frame.

[0011] Preferably, the tooth blocks are provided in two sets, and the tooth blocks are symmetrically distributed about the central axis of the grinding cylinder. The transmission gear has several sets of teeth on its outside. The transmission gear and the tooth blocks are meshed and connected. The zirconia balls are provided in several sets, and the grinding blocks are provided in several sets. The grinding blocks are distributed in a ring array about the central axis of the grinding cylinder.

[0012] Preferably, the screening mechanism includes an eccentric wheel, a second connecting rod, and a screening frame. The eccentric wheel is fixed to the outside of the first connecting rod, and the second connecting rod is fixed to the outside of the eccentric wheel. The screening frame is slidably connected inside the screening box, and a screening screen is fixed inside the screening frame. A return spring is fixed to the top of the screening frame.

[0013] Preferably, there are two sets of eccentric wheels, which are symmetrically distributed about the central axis of the screening box. There are six sets of return springs, which are symmetrically distributed about the central axis of the screening frame. The return springs are used to squeeze the screening frame and keep it moving downward.

[0014] Preferably, the limiting mechanism includes a third servo motor, a fan blade, and a first cylinder. The third servo motor is fixed to the outside of the screening box, and a fan blade is fixed to the rotating end of the third servo motor. The first cylinder is fixed to the top of the screening box, and a first limiting plate is fixed to the top of the first cylinder. A powder outlet is fixed to one end of the screening box, and a second cylinder is fixed to the top of the powder outlet. A second limiting plate is fixed to the top of the second cylinder.

[0015] Preferably, there are two sets of the first cylinders, which are symmetrically distributed about the central axis of the first limiting plate, and two sets of the second cylinders, which are symmetrically distributed about the central axis of the second limiting plate.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention, through the combination of a mounting frame, a first servo motor, and a crushing roller, enables the device to effectively coarsely crush selected calcite and marble minerals with a calcium carbonate content ≥98%. Two sets of first servo motors drive the crushing rollers to rotate symmetrically within the crushing box, which can coarsely crush the raw material to 2-5cm, providing initial raw materials of suitable particle size for subsequent processing. Furthermore, the mounting frame provides stable support for the entire crushing mechanism, ensuring the smooth progress of the crushing process.

[0017] This invention enables the device to grind raw materials efficiently by setting up a second servo motor, a first connecting rod, and a transmission gear. The second servo motor drives the first connecting rod and the transmission gear to rotate. The transmission gear meshes with the toothed blocks on the outside of the grinding cylinder, thereby driving the grinding cylinder to rotate. Combined with the zirconia balls and grinding blocks inside, under the condition of a ball-to-material ratio of 8-10:1, the raw materials can be ground to the required fineness, improving grinding efficiency and effect.

[0018] This invention, through the combination of an eccentric wheel, a second connecting rod, and a screening frame, enables the device to effectively screen the ground material. The first connecting rod drives the eccentric wheel to rotate, and the second connecting rod squeezes the screening frame. With the help of the return spring, the screening screen on the screening frame vibrates continuously for screening. Coarse particles are returned to the grinding cylinder for further grinding, ensuring a uniform particle size distribution in the product.

[0019] This invention, through the coordinated arrangement of a third servo motor, fan blades, and a first cylinder, enables the device to conveniently collect qualified materials after screening. When a certain amount of qualified material is collected, the first cylinder drives the first limiting plate to lift, and the third servo motor drives the fan blades to rotate and generate airflow, which can blow the qualified material at the bottom of the screening box out through the powder outlet. At the same time, the second cylinder drives the second limiting plate to ensure smooth material discharge and improve collection efficiency. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a schematic diagram of the overall rear view structure of the present invention; Figure 3 This is a schematic diagram of the crushing mechanism of the present invention; Figure 4 This is a schematic diagram of the grinding mechanism structure of the present invention; Figure 5 This is a partial structural diagram of the grinding mechanism of the present invention; Figure 6 This is a schematic diagram of the sieving box structure of the present invention; Figure 7 This is a schematic diagram of the screening mechanism of the present invention; Figure 8 This is a schematic cross-sectional view of the screening box structure of the present invention; Figure 9 This is a schematic diagram of the limiting mechanism structure of the present invention.

[0021] In the diagram: 1. Support leg; 2. Crushing mechanism; 201. Mounting frame; 202. First servo motor; 203. Breaking roller; 204. Crushing box; 205. Discharge port; 206. Guide plate; 207. Feed pipe; 208. Fan; 3. Support frame; 4. Grinding cylinder; 5. Grinding mechanism; 501. Second servo motor; 502. First connecting rod; 503. Transmission gear; 504. Tooth block; 505. Oxidizing agent. Zirconium ball; 506, grinding block; 6, discharge pipe; 7, sieve box; 8, sieve mechanism; 801, eccentric wheel; 802, second connecting rod; 803, sieve frame; 804, sieve screen; 805, return spring; 9, limit mechanism; 901, third servo motor; 902, fan blade; 903, first cylinder; 904, first limit plate; 905, powder outlet; 906, second cylinder; 907, second limit plate. Detailed Implementation

[0022] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] like Figures 1 to 9 As shown, the present invention provides a method for preparing heavy calcium carbonate, comprising the following steps: S1. Select calcite and marble minerals with a calcium carbonate content ≥98%, clean them, add them into the crushing box 204 for coarse crushing to 2-5cm, and place them in a low-temperature plasma reaction device. In a mixed gas atmosphere of argon 10-15L / min and oxygen 0.5-1L / min, apply a voltage of 10-15kV for 5-10 minutes. S2. The activated raw material, along with 0.5%-1% of polyether-type grinding aid and 1%-2% of organic-inorganic hybrid modifier, is added into the grinding cylinder 4 through the opening at the top of the feed pipe 207 for grinding. The ball-to-material ratio of zirconia balls 505 inside the grinding cylinder 4 is 8-10:1. The ground material is then conveyed to the top of the screening box 7 for screening, so that particles of the required size pass through the screening screen 804. Fine particles with d97≤2μm are collected, while coarse particles are returned to the grinding cylinder 4 for re-grinding, ensuring uniform particle size distribution of the product. S3. After classification, the heavy calcium carbonate slurry with a solid content of 30%-40% is sprayed into liquid nitrogen at -30℃--40℃ through a high-pressure nozzle of 10-15MPa and instantly frozen into tiny particles. Then, it is transferred to a vacuum freeze-drying equipment and sublimated and dried at a vacuum of 10-20Pa and -20℃--10℃ to maintain the particle dispersion and fine particle size. S4. The dried particles are placed in a high-pressure reactor, and 0.05-0.1 mol / L of a mixed crystal form regulator of sodium citrate and diammonium hydrogen phosphate is added. The mixture is reacted at 80-120℃ and 2-3 MPa for 1-2 hours to form a stable and regular crystal structure. The heavy calcium carbonate product is then placed in a fluidized bed reactor, and long-chain alkyl organosilicon compound vapor is introduced at 50-80℃. The reaction is carried out for 1-2 hours to form a protective film on the product surface.

[0024] like Figures 1 to 9 As shown, the present invention also provides a heavy calcium carbonate preparation device, including a support leg 1, a crushing mechanism 2 fixed at the top of the support leg 1, a support frame 3 provided at one end of the crushing mechanism 2, a grinding cylinder 4 provided at one end of the crushing mechanism 2, a grinding mechanism 5 fixed outside the support frame 3, a discharge pipe 6 fixed at one end of the support frame 3, a screening box 7 provided at the bottom end of the discharge pipe 6, a screening mechanism 8 installed inside the screening box 7, and a limit mechanism 9 provided at one end of the screening box 7.

[0025] like Figures 1 to 3 As shown, the crushing mechanism 2 includes a mounting frame 201, a first servo motor 202, and a crushing roller 203. The mounting frame 201 is fixed to the top of the support leg 1. The first servo motor 202 is fixed to the top of the mounting frame 201. The crushing roller 203 is fixed to the rotating end of the first servo motor 202. The crushing box 204 is fixed to the top of the mounting frame 201. A discharge port 205 is opened at one end of the crushing box 204. A guide plate 206 is fixed to one end of the discharge port 205. The bottom end of the guide plate 206 is connected to a feed pipe 207. A fan 208 is installed at one end of the feed pipe 207. Two sets of the first servo motor 202 and the crushing roller 203 are provided. The first servo motor 202 and the crushing roller 203 are symmetrically distributed about the central axis of the crushing box 204. A support frame 3 is fixed to the outside of the feed pipe 207. A grinding cylinder 4 is rotatably connected to the outside of the feed pipe 207.

[0026] The above scheme is adopted as follows: calcite and marble minerals with a calcium carbonate content of ≥98% are selected, cleaned and added into the crushing box 204. Two sets of first servo motors 202 are started to drive the crushing rollers 203 to rotate, so that the crushing rollers 203 crush the raw materials. After the crushed raw materials are activated, they are conveyed into the feed pipe 207 through the discharge port 205 and the guide plate 206. The blower 208 is started to blow the material into the grinding cylinder 4.

[0027] like Figures 1 to 5 As shown, the grinding mechanism 5 includes a second servo motor 501, a first connecting rod 502, and a transmission gear 503. The second servo motor 501 is fixed to the outside of the support frame 3. The first connecting rod 502 is fixed to the rotating end of the second servo motor 501. The transmission gear 503 is fixed to the outside of the first connecting rod 502. Tooth blocks 504 are fixed to the outside of the grinding cylinder 4. Zirconia balls 505 are arranged inside the grinding cylinder 4. Grinding blocks 506 are fixed inside the grinding cylinder 4. There are two sets of transmission gears 503, which are symmetrically distributed about the central axis of the support frame 3. There are two sets of tooth blocks 504, which are symmetrically distributed about the central axis of the grinding cylinder 4. Several sets of teeth are arranged on the outside of the transmission gears 503. The transmission gears 503 and tooth blocks 504 are meshed and connected. There are several sets of zirconia balls 505 and several sets of grinding blocks 506, which are arranged in a ring array about the central axis of the grinding cylinder 4.

[0028] The above scheme is adopted: by starting the second servo motor 501, the first connecting rod 502 and the transmission gear 503 are driven to rotate. The rotation of the transmission gear 503 meshes with the tooth block 504, thereby driving the grinding cylinder 4 to rotate as a whole. This causes the zirconia balls 505 to roll inside the grinding cylinder 4. The raw material between the multiple sets of zirconia balls 505 is ground by the falling of the zirconia balls 505 and the cooperation of the grinding blocks 506.

[0029] like Figures 1 to 9 As shown, the screening mechanism 8 includes an eccentric wheel 801, a second connecting rod 802, and a screening frame 803. The eccentric wheel 801 is fixed to the outside of the first connecting rod 502, and the second connecting rod 802 is fixed to the outside of the eccentric wheel 801. The screening frame 803 is slidably connected inside the screening box 7. The screening screen 804 is fixed inside the screening frame 803. A return spring 805 is fixed to the top of the screening frame 803. There are two sets of eccentric wheels 801, which are symmetrically distributed about the central axis of the screening box 7. There are six sets of return springs 805, which are symmetrically distributed about the central axis of the screening frame 803. The return springs 805 are used to squeeze the screening frame 803 and keep it in a downward moving trend.

[0030] The above scheme is adopted: when the ground material is discharged through the discharge pipe 6, it falls into the interior of the screening box 7 and is located at the top of the screening screen 804. When the first connecting rod 502 drives the grinding cylinder 4 to rotate, it simultaneously drives the two sets of eccentric wheels 801 to rotate. Then, the shape of the eccentric wheels 801 squeezes the screening frame 803, thereby lifting the screening frame 803. After the eccentric wheels 801 rotate half a turn, the restoring force of the return spring 805 quickly resets the screening frame 803, thereby screening the ground material located at the top of the screening screen 804, so that the qualified material enters the bottom of the screening box 7.

[0031] like Figures 1 to 9 As shown, the limiting mechanism 9 includes a third servo motor 901, a fan blade 902, and a first cylinder 903. The third servo motor 901 is fixed to the outside of the screening box 7. The fan blade 902 is fixed to the rotating end of the third servo motor 901. The first cylinder 903 is fixed to the top of the screening box 7. The first limiting plate 904 is fixed to the top of the first cylinder 903. A powder outlet 905 is fixed to one end of the screening box 7. A second cylinder 906 is fixed to the top of the powder outlet 905. A second limiting plate 907 is fixed to the top of the second cylinder 906. Two sets of the first cylinder 903 are provided, and the first cylinder 903 is symmetrically distributed about the central axis of the first limiting plate 904. Two sets of the second cylinder 906 are provided, and the second cylinder 906 is symmetrically distributed about the central axis of the second limiting plate 907.

[0032] Using the above scheme: when a certain amount of qualified material is collected, the first cylinder 903 and the second cylinder 906 are started to lift the first limit plate 904 and the second limit plate 907, and the third servo motor 901 is started to drive the fan blade 902 to rotate, so that the fan blade 902 can generate outward wind force when rotating, thereby blowing the material at the bottom of the screening box 7 through the powder outlet 905.

[0033] The working principle and usage process of this invention are as follows: Calcite and marble minerals with a calcium carbonate content ≥98% are selected, cleaned, and added to the inside of the crushing box 204. Two sets of first servo motors 202 are activated to drive the crushing rollers 203 to rotate, causing the crushing rollers 203 to crush the raw materials. After activation, the crushed raw materials are conveyed into the feed pipe 207 through the discharge port 205 and guide plate 206. The blower 208 is activated to blow the material into the grinding cylinder 4. The second servo motor 501 is activated to drive the first connecting rod 502 and the transmission gear 503 to rotate. The rotation of the transmission gear 503 meshes with the toothed block 504, thereby driving the grinding cylinder 4 to rotate as a whole. This causes the zirconia balls 505 to roll inside the grinding cylinder 4. The falling of the zirconia balls 505 and the cooperation of the grinding blocks 506 grind the raw materials located between the multiple sets of zirconia balls 505, resulting in the grinding process. When the material is discharged through the discharge pipe 6, it falls into the interior of the screening box 7 and is located at the top of the screening screen 804. When the first connecting rod 502 drives the grinding cylinder 4 to rotate, it simultaneously drives the two sets of eccentric wheels 801 to rotate. The shape of the eccentric wheels 801 then squeezes the screening frame 803, thereby lifting the screening frame 803. After the eccentric wheels 801 rotate half a turn, the restoring force of the return spring 805 quickly resets the screening frame 803, thereby screening the ground material located at the top of the screening screen 804. This allows the qualified material to enter the bottom of the screening box 7. When a certain amount of qualified material is collected, the first cylinder 903 and the second cylinder 906 are activated to lift the first limit plate 904 and the second limit plate 907. The third servo motor 901 is also activated to drive the fan blade 902 to rotate. When the fan blade 902 rotates, it generates outward airflow, which blows the material at the bottom of the screening box 7 and discharges it through the powder outlet 905.

[0034] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0035] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for preparing heavy calcium carbonate, characterized in that: Includes the following steps: S1. Select calcite and marble minerals with a calcium carbonate content ≥98%, clean them, and add them into the crushing box (204) for coarse crushing to 2-5cm. After crushing, place them in a low-temperature plasma reaction device and apply a 10-15kV voltage for 5-10 minutes in a mixed gas atmosphere of argon 10-15L / min and oxygen 0.5-1L / min. S2. The activated raw material, along with 0.5%-1% of polyether-type grinding aid and 1%-2% of organic-inorganic hybrid modifier, is added into the grinding cylinder (4) through the opening at the top of the feed pipe (207) for grinding. The ball-to-material ratio of zirconia balls (505) inside the grinding cylinder (4) is 8-10:

1. The ground material is then conveyed to the top of the sieve box (7) for sieving, so that particles of the required size pass through the sieve screen (804). Fine particles with d97≤2μm are collected, while coarse particles are returned to the grinding cylinder (4) for re-grinding, ensuring uniform particle size distribution of the product. S3. After classification, the heavy calcium carbonate slurry with a solid content of 30%-40% is sprayed into liquid nitrogen at -30℃~-40℃ through a high-pressure nozzle of 10-15MPa and instantly frozen into tiny particles. Then, it is transferred to a vacuum freeze-drying equipment and sublimated and dried at a vacuum of 10-20Pa and -20℃~-10℃ to maintain the particle dispersion and fine particle size. S4. The dried particles are placed in a high-pressure reactor, and 0.05-0.1 mol / L of a mixed crystal form regulator of sodium citrate and diammonium hydrogen phosphate is added. The mixture is reacted at 80-120℃ and 2-3 MPa for 1-2 hours to form a stable and regular crystal structure. The heavy calcium carbonate product is then placed in a fluidized bed reactor, and long-chain alkyl organosilicon compound vapor is introduced at 50-80℃. The reaction is carried out for 1-2 hours to form a protective film on the product surface.

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