Multistage circulating screening and unloading system for calcium carbonate production

Abstract

The invention discloses a multistage circulating screening and discharging system for calcium carbonate production. The multistage circulating screening and discharging system comprises a first-stage grading system, a second-stage grading system and a circulating screening system. A discharging screw is arranged at the discharging end of the first-stage stock bin and can convey materials to a first-stage finished product packaging area or a second-stage feeding air pipe. A discharging screw is arranged at the discharging end of the second-stage stock bin and can convey materials to a second-stage finished product packaging area or a material returning draught fan. And the primary feeding air pipe is connected with a raw material feeding pipe. According to the circulating screening system, excess materials in the second-stage stock bin are re-injected into the first-stage feeding air pipe through the material returning fan to be sorted, closed-loop circulation is formed, fine particles which are not fully captured repeatedly participate in the grading process, the comprehensive output rate of finished products is remarkably increased, and raw material waste is remarkably reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of calcium carbonate production, and particularly relates to a multi-stage circulating screening and discharging system for calcium carbonate production. Background Art

[0002] Calcium carbonate, as an important industrial raw material, is widely used in industries such as building materials, papermaking, and plastics. Limestone, as the main mineral form of calcium carbonate, the classification and screening process in its processing directly affects the product added value and resource utilization rate. Currently, two-stage classification and discharging are usually carried out through a primary classification system and a secondary classification system. However, it is found in actual production that the remaining materials after two-stage screening still contain 15 - 25% of fine particle products that meet the particle size standard. This phenomenon is due to multiple factors such as mechanical vibration attenuation, micropore blockage of the sieve mesh, and particle agglomeration effect during the screening process. This not only causes about 8 - 12% of the finished product loss, but also leads to an increase in energy consumption in the subsequent return material treatment process, resulting in a double pressure of resource waste and production cost. There is an urgent need to develop a more efficient classification process to improve the capture efficiency of fine particles, which has important practical significance for improving the utilization rate of mineral resources and the economic benefits of enterprises. Summary of the Invention

[0003] The present invention aims to solve at least one of the technical problems existing in the prior art. For this purpose, the present invention provides a multi-stage circulating screening and discharging system for calcium carbonate production.

[0004] One embodiment of the present invention adopts the following technical solution to solve its technical problems: A multi-stage circulating screening and discharging system for calcium carbonate production, comprising: a primary classification system, a secondary classification system, and a circulating screening system;

[0005] The primary classification system includes a primary fan, a primary classifier, a primary classification finished product bin, and a primary material bin connected by air ducts; the primary fan is connected to the feed inlet of the primary classifier through a primary feed air duct; the discharge end of the primary classifier is respectively communicated with the primary classification finished product bin and the primary material bin; a primary finished product packing area is arranged below the primary classification finished product bin and the primary material bin;

[0006] The secondary classification system includes a secondary fan, a secondary classifier, a secondary classification finished product bin, and a secondary material bin connected by air ducts; the secondary fan is connected to the feed inlet of the secondary classifier through a secondary feed air duct; the discharge end of the secondary classifier is respectively communicated with the secondary classification finished product bin and the secondary material bin; a secondary finished product packing area is arranged below the secondary classification finished product bin and the secondary material bin;

[0007] The circulating screening system includes a return air fan and a circulating material bin connected by air ducts; the discharge end of the circulating material bin is connected to the primary feed air duct;

[0008] A feeding screw is provided at the discharge end of the first-stage silo, which can convey materials to the first-stage finished product packing area or the second-stage feeding air duct; a feeding screw is provided at the discharge end of the second-stage silo, which can send materials to the second-stage finished product packing area or the return air blower; the first-stage feeding air duct is connected with a raw material feeding pipe.

[0009] Optionally, feeding screws are provided at the discharge ends of the first-stage classified finished product silo, the first-stage silo, the second-stage classified finished product silo and the second-stage silo to control the discharging path.

[0010] Optionally, a bulk bag packing area and a finished product packing machine are provided in the first-stage finished product packing area and the second-stage finished product packing area.

[0011] Optionally, induced draft fans are provided in the air ducts of the first-stage classification system, the second-stage classification system and the circulating screening system.

[0012] Optionally, an exhaust valve is provided in the circulating silo.

[0013] Optionally, pneumatic on-off valves and exhaust valves are connected to the first-stage fan and the second-stage fan.

[0014] Advantages of the present invention: The multi-stage circulating screening and discharging system for calcium carbonate production provided by the present invention significantly improves the sorting efficiency and resource utilization rate of calcium carbonate through the collaborative design of multi-stage classification and circulating screening. The two-stage classification system realizes the high-precision separation of calcium carbonate with different particle sizes through the linkage of the fan and the classifier, combining air flow separation and mechanical screening, effectively reducing the screen blockage and particle agglomeration phenomena; the circulating screening system forms a closed-loop cycle by re-injecting the remaining materials in the second-stage silo into the first-stage feeding air duct through the return air blower for sorting, enabling the fine particles that have not been fully captured to repeatedly participate in the classification process, significantly improving the comprehensive output rate of the finished product and significantly reducing raw material waste. While improving the finished product yield, it also has the advantages of energy conservation and consumption reduction and reduced maintenance costs, which is of great significance for promoting the green and efficient development of the calcium carbonate processing industry.

[0015] To make the above objects, features and advantages of the present invention more obvious and understandable, the following specific preferred embodiments are given below in conjunction with the accompanying drawings and are described in detail as follows. Description of the Drawings

[0016] The above and / or additional aspects and advantages of the present invention will become obvious and easy to understand from the description of the embodiments in conjunction with the following drawings, in which:

[0017] Figure 1 is a schematic structural diagram of the multi-stage circulating screening and discharging system for calcium carbonate production of the present invention.

[0018] Main reference numerals:

[0019] 10. Primary classification system; 11. Primary fan; 12. Primary classifier; 13. Primary classified finished product bin; 14. Primary bin; 15. Primary feed air duct; 16. Primary finished product packing area; 20. Secondary classification system; 21. Secondary fan; 22. Secondary classifier; 23. Secondary classified finished product bin; 24. Secondary bin; 25. Secondary feed air duct; 26. Secondary finished product packing area; 30. Circulation screening system; 31. Return air fan; 32. Circulation bin; 40. Feeding screw; 41. Ton bag packing area; 42. Finished product packing machine; 50. Raw material feed pipe; 60. Air lock; 61. Exhaust valve; 62. Pneumatic on-off valve. Detailed implementation manners

[0020] This part will describe the specific embodiments of the present invention in detail. The preferred embodiments of the present invention are shown in the drawings. The role of the drawings is to supplement the description of the text part of the specification, enabling people to intuitively and vividly understand each technical feature and the overall technical solution of the present invention. However, it should not be construed as a limitation on the protection scope of the present invention.

[0021] In the description of the present invention, the meaning of "plural" is more than two. Understandings such as "greater than", "less than", and "exceeding" do not include the original number, and understandings such as "above", "below", and "within" include the original number. If there is a description of "first" and "second", it is only for the purpose of distinguishing technical features and cannot be construed as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features or implicitly indicating the sequence relationship of the indicated technical features.

[0022] In the description of the present invention, it should be understood that for the orientation description, such as the orientation or position relationship indicated by "upper", "lower", "front", "rear", "left", "right", etc., is based on the orientation or position relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the indicated device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be construed as a limitation on the present invention.

[0023] In the present invention, unless otherwise clearly defined, words such as "set", "install", and "connect" should be understood in a broad sense. For example, they can be directly connected, or indirectly connected through an intermediate medium; they can be fixedly connected, or detachably connected, or integrally formed; they can be mechanically connected; they can be the communication inside two elements or the interaction relationship between two elements. Those skilled in the art can reasonably determine the specific meanings of the above words in the present invention in combination with the specific content of the technical solution.

[0024] Embodiment

[0025] Refer to Figure 1, a multi - stage circulating screening and discharging system for calcium carbonate production proposed by the present invention includes: a primary classification system 10, a secondary classification system 20, and a circulating screening system 30;

[0026] The primary classification system 10 includes a primary fan 11, a primary separator 12, a primary classified finished product bin 13, and a primary bin 14 connected by air ducts; the primary fan 11 is connected to the feed inlet of the primary separator 12 through a primary feed air duct 15; the discharge ends of the primary separator 12 are respectively connected to the primary classified finished product bin 13 and the primary bin 14; a primary finished product packing area 16 is provided below the primary classified finished product bin 13 and the primary bin 14;

[0027] The secondary classification system 20 includes a secondary fan 21, a secondary separator 22, a secondary classified finished product bin 23, and a secondary bin 24 connected by air ducts; the secondary fan 21 is connected to the feed inlet of the secondary separator 22 through a secondary feed air duct 25; the discharge ends of the secondary separator 22 are respectively connected to the secondary classified finished product bin 23 and the secondary bin 24; a secondary finished product packing area 26 is provided below the secondary classified finished product bin 23 and the secondary bin 24;

[0028] The circulating screening system 30 includes a return air fan 31 and a circulating bin 32 connected by air ducts; the discharge end of the circulating bin 32 is connected to the primary feed air duct 15;

[0029] A feeding screw 40 is provided at the discharge end of the primary bin 14, which can convey materials to the primary finished product packing area 16 or the secondary feed air duct 25; a feeding screw 40 is provided at the discharge end of the secondary bin 24, which can send materials to the secondary finished product packing area 26 or the return air fan 31; the primary feed air duct 15 is connected to a raw material feed pipe 50.

[0030] In the present invention, the multi - stage circulating screening and discharging system for calcium carbonate production provided by the present invention significantly improves the sorting efficiency and resource utilization rate of calcium carbonate through the collaborative design of multi - stage classification and circulating screening. The two - stage classification system realizes the high - precision separation of calcium carbonate with different particle sizes through the linkage of the fan and the separator, combining air - flow separation and mechanical screening, effectively reducing the screen clogging and particle agglomeration phenomena; the circulating screening system 30 re - injects the surplus materials in the secondary bin 24 into the primary feed air duct 15 through the return air fan 31 for sorting, forming a closed - loop cycle, enabling the fine particles that have not been fully captured to participate in the classification process repeatedly, significantly improving the comprehensive output rate of the finished product, and significantly reducing raw material waste. While improving the finished product yield, it also has the advantages of energy conservation, consumption reduction, and reduced maintenance costs, which is of great significance for promoting the green and efficient development of the calcium carbonate processing industry.

[0031] In this embodiment, feeding screws 40 are provided at the discharge ends of the primary classification finished product bin 13, the primary bin 14, the secondary classification finished product bin 23, and the secondary bin 24 to control the discharge path. Through the directional adjustment of screw conveying, the material flow direction can be flexibly switched (such as direct packing or entering the next-stage sorting), avoiding the blockage problem caused by the switching of traditional valves and improving the operation stability of the system. The screw drive is linked with the sensor to realize the intelligent control of the discharge path, reduce manual intervention, and improve production efficiency.

[0032] In this embodiment, a bulk bag packing area 41 and a finished product packing machine 42 are provided in the primary finished product packing area 16 and the secondary finished product packing area 26. The bulk bag packing machine is directly connected to the discharge port at one end of the classified finished product bin or bin, realizing continuous and automatic packaging, improving the packaging speed, and reducing dust leakage during the packaging process; the finished product packing machine 42 can pack according to the packing structures of different packing specifications, be quickly replaced, meet the diverse needs of customers, and at the same time reduce the manual handling intensity.

[0033] In this embodiment, a rotary air lock 60 is provided in the air ducts of the primary classification system 10, the secondary classification system 20, and the circulating screening system 30. The rotary air lock 60 can block the reverse flow of air, maintain the pressure balance inside the classification system, and reduce the particle sorting deviation caused by pressure fluctuations; by reducing the ineffective air circulation, the energy consumption of the system fan is reduced.

[0034] In this embodiment, an exhaust valve 61 is provided in the circulating bin 32. The exhaust valve 61 releases the excessive gas accumulated in the circulating bin 32 in real time, avoiding material backflush or equipment damage caused by excessive pressure, and significantly improving the system safety.

[0035] In this embodiment, a pneumatic on-off valve 62 and an exhaust valve 61 are connected to the primary fan 11 and the secondary fan 21. The fast response characteristic of the pneumatic valve can avoid the idling of the fan.

[0036] Certainly, the present invention is not limited to the above embodiments. Those skilled in the art can make equivalent deformations or substitutions without departing from the spirit of the present invention, and these equivalent deformations and substitutions are all included in the scope defined by the claims of this application.

Claims

1. A multi-stage circulation screening and unloading system for calcium carbonate production, characterized in that: include: A primary grading system (10), a secondary grading system (20) and a circulation screening system (30); The primary classification system (10) comprises a primary fan (11), a primary powder selector (12), a primary classification finished product bin (13) and a primary material bin (14) connected via an air duct; the primary fan (11) is connected to the feed port of the primary powder selector (12) via a primary feed air duct (15); the discharge end of the primary powder selector (12) is respectively connected to the primary classification finished product bin (13) and the primary material bin (14); a primary finished product packaging area (16) is provided below the primary classification finished product bin (13) and the primary material bin (14); The secondary grading system (20) comprises a secondary fan (21), a secondary powder selector (22), a secondary grading finished product bin (23) and a secondary material bin (24) connected via an air duct; the secondary fan (21) is connected to the feed port of the secondary powder selector (22) via a secondary feed air duct (25); the discharge end of the secondary powder selector (22) is respectively connected to the secondary grading finished product bin (23) and the secondary material bin (24); a secondary finished product packaging area (26) is provided below the secondary grading finished product bin (23) and the secondary material bin (24); The circulating screening system (30) comprises a return blower (31) and a circulating silo (32) connected via an air duct; the discharge end of the circulating silo (32) is connected to the primary feed duct (15); The discharge end of the primary silo (14) is provided with a discharge screw (40) for conveying materials to the primary finished product packaging area (16) or the secondary feeding air duct (25); the discharge end of the secondary silo (24) is provided with a discharge screw (40) for conveying materials to the secondary finished product packaging area (26) or the return fan (31); the primary feeding air duct (15) is connected to a raw material feeding pipe (50).

2. The multi-stage circulation screening and unloading system for calcium carbonate production according to claim 1 is characterized in that: The discharge ends of the first-level grading finished product bin (13), the first-level material bin (14), the second-level grading finished product bin (23) and the second-level material bin (24) are all provided with the unloading screw rod (40) to control the unloading path.

3. The multi-stage circulation screening and unloading system for calcium carbonate production according to claim 2 is characterized in that: The first-level finished product packaging area (16) and the second-level finished product packaging area (26) are provided with a ton bag packaging area (41) and a finished product packaging machine (42).

4. The multi-stage circulation screening and unloading system for calcium carbonate production according to claim 1 is characterized in that: The air ducts of the primary grading system (10), the secondary grading system (20) and the circulation screening system (30) are provided with related fans (60).

5. The multi-stage circulation screening and unloading system for calcium carbonate production according to claim 1 is characterized in that: The circulation silo (32) is provided with an exhaust valve (61).

6. The multi-stage circulation screening and unloading system for calcium carbonate production according to claim 1 is characterized in that: The primary fan (11) and the secondary fan (21) are connected to a pneumatic on-off valve (62) and an exhaust valve (61).

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