Method and system for removing mica from granite manufactured sand

Abstract

The application discloses a method for removing mica from granite machine-made sand, which comprises the following steps: S1, screening and grading semi-finished machine-made sand to obtain coarse sand and fine sand; S2, removing flaky mica from the coarse sand through air separation to obtain heavy products and light products; S3, removing micro-fine mica with weak magnetism from the fine sand through high-gradient wet magnetic separation to obtain non-magnetic products and magnetic products; and S4, combining the heavy products with the non-magnetic products to obtain full-grain-level machine-made sand with a mica content of less than 2%. The application provides a method and system for removing mica from granite machine-made sand, which can effectively reduce the mica content in full-grain-level machine-made sand by screening into coarse materials and fine materials and then performing air separation on the coarse materials and magnetic separation on the fine materials, so that the requirement of the national standard and the industrial standard that the mica content is less than or equal to 2% is met; the mica is fully separated from the sand and stone materials by kneading before screening, so that the subsequent screening is facilitated, and the screening effect and the quality of the finished product after screening are ensured.

Description

Technical Field

[0001] This invention relates to the field of manufactured sand processing technology, specifically to a method and system for removing mica from manufactured granite sand. Background Technology

[0002] Sand and gravel are essential raw materials for infrastructure construction, including buildings, water conservancy projects, roads, bridges, and municipal works. To meet engineering needs and environmental requirements, manufactured sand is gradually replacing natural sand as the main raw material for concrete. Currently, many hydropower projects utilize locally sourced materials, producing artificial aggregates from excavated rocks. Mica is commonly found in the parent rocks of sand and gravel raw materials such as granite and marble.

[0003] In the production of manufactured sand from granite, the crushing process releases mica particles. Without effective mica removal measures, these particles will eventually enter the finished sand. Layered mica has low strength and poor adhesion to cement paste. Numerous studies have shown that when the mica content in manufactured sand exceeds a certain limit, it significantly reduces the strength and durability of the sand, severely impacting the compressive and tensile strength of concrete. Therefore, national and industry standards clearly limit the mica content in sand to no more than 2%, such as GB / T 14684 "Construction Sand" and DL / T 5144 "Specification for Hydraulic Concrete Construction". Against this backdrop, when using granite with high mica content to produce manufactured sand, selecting a suitable mica removal method becomes crucial in determining the quality of the finished sand.

[0004] Traditional methods for removing mica from manufactured sand mainly include air classification, magnetic separation, and wet screening. Air classification works by utilizing the flaky structure of mica, which separates and flakes along its cleavage planes during crushing. A horizontal airflow separates the lighter, flaky mica from the heavier sand and gravel. Air classification is simple and inexpensive, but it suffers from poor separation accuracy for fine particles. The finer the material, the smaller the shape differences, and mica is typically concentrated in fine-grained manufactured sand. For fine particles, the airflow struggles to effectively distinguish particles of different densities or shapes, resulting in the loss of fine-grained manufactured sand and an increase in the fineness modulus of the separated sand. Magnetic separation primarily targets magnetic mica such as biotite and ferromica, using the difference in magnetic properties between mica and sand / grain for separation. Its advantage is significant separation, especially for fine particles, as finer particles result in more complete mica dissociation and higher separation accuracy. However, for finer particles, it has limitations. Coarse materials, due to the inclusions or intergrowths formed by incomplete dissociation of mica, have a certain magnetic properties. These intergrowths will be removed along with the mica, which not only wastes sand and gravel but also reduces the fineness modulus of the selected manufactured sand. The wet screening method mainly utilizes the light texture and flaky structure of mica in water to initially separate the mica using a spiral chute. For wastewater containing sand, the mica is then screened out to recover fine sand and gravel powder. Although this method is simple in principle and easy to operate, it consumes a lot of water. It has a good separation effect on lighter materials such as muscovite, potassium mica, and sericite, but it is difficult to separate heavier materials such as biotite.

[0005] In summary, existing methods for removing mica from manufactured sand suffer from problems such as difficulty in achieving efficient separation of all particle sizes, unreasonable gradation of sand and gravel after separation, resource waste, and low efficiency. Therefore, there is an urgent need to find a new method for removing mica from manufactured granite sand with high mica content, which can effectively reduce the mica content in the sand while producing sand and gravel aggregates with gradation that meet the specifications.

[0006] Furthermore, existing methods directly screen manufactured sand, but manufactured sand contains a large amount of mica-grain aggregates. These mica-grain aggregates are mixed into the finished manufactured sand and cannot be screened out, resulting in poor mica removal and affecting the quality of the finished manufactured sand. Summary of the Invention

[0007] The main objective of this invention is to provide a method and system for removing mica from manufactured granite sand, thereby solving the problems of existing methods for removing mica from manufactured sand, which have difficulty in achieving efficient separation across all particle sizes and have poor separation effects.

[0008] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0009] A method for removing mica from manufactured granite sand includes the following steps:

[0010] S1. Screen and classify the semi-finished manufactured sand to obtain coarse sand and fine sand;

[0011] S2. Remove the flaky mica from the coarse sand by air classification to obtain heavy and light products;

[0012] S3. Fine sand is subjected to high-gradient wet magnetic separation to remove weakly magnetic micro-mica, resulting in non-magnetic and magnetic products.

[0013] S4. Combine heavy products with non-magnetic products to obtain fully-sized manufactured sand with a mica content of <2%.

[0014] In a preferred embodiment, the sieve aperture size used for sieving and grading in step S1 is 0.8~1.5mm.

[0015] In the preferred embodiment, in step S2, the coarse sand obtained from screening is air-dried and then air-separated at a wind speed of 2~10m / s.

[0016] In the preferred embodiment, the magnetic field strength of the magnetic separation in step S3 is 10000~20000 Oe.

[0017] In the preferred embodiment, in step S3, the non-magnetic product after magnetic separation is dehydrated by a dehydration screen, and the magnetic product is dried by a drying unit.

[0018] In the preferred embodiment, in step S4, the heavy product and the non-magnetic product are mixed using a mixing device to obtain fully graded manufactured sand with a gradation that meets the specifications.

[0019] A system for removing mica from granite manufactured sand includes a primary screening mechanism and two secondary screening mechanisms. The primary screening mechanism is used to screen coarse sand and fine sand, and the two secondary screening mechanisms are used to screen the coarse sand and fine sand obtained by the primary screening mechanism.

[0020] The primary screening mechanism includes a kneading device for kneading semi-finished manufactured sand to facilitate the separation of mica.

[0021] In the preferred embodiment, the secondary screening mechanism includes an air separator and a magnetic separator. The air separator is equipped with a drying chamber at its feed end, and the magnetic separator is equipped with a drying unit and a dewatering screen at its discharge end. The drying unit is used to dry magnetic products, and the dewatering screen is used to process non-magnetic products.

[0022] The products separated by the air classifier are mixed with non-magnetic products through a mixing device.

[0023] In a preferred embodiment, the primary screening mechanism also includes a linear vibrating screen, which is used to screen the products processed by the kneading equipment.

[0024] The kneading equipment includes a support frame and a rotating cylinder. The top of the support frame is provided with multiple guide rings, which are connected to the outside of the rotating cylinder through bearings. One end of the rotating cylinder is provided with a feed pipe, and the outer circumferential surface of the rotating cylinder is provided with a first discharge hole and a discharge mechanism.

[0025] The rotating cylinder is equipped with a drive frame, which includes a first turntable and a second turntable. The first turntable and the second turntable are movably connected to the two ends of the inner wall of the rotating cylinder. A grinding roller is provided between the first turntable and the second turntable, and the grinding roller is located at the bottom end of the inner wall of the rotating cylinder.

[0026] The top of the support frame is equipped with a motor frame, the top of the motor frame is equipped with a first motor and a fixed frame, the output end of the first motor is equipped with a reducer, the output shaft of the first motor is connected to the input shaft of the reducer, the output shaft of the reducer is connected to a gear shaft, the gear shaft passes through the fixed frame, the gear shaft is connected to a drive gear, the outside of the rotating cylinder is equipped with a gear ring, and the drive gear meshes with the gear ring.

[0027] In a preferred embodiment, the kneading device includes a support frame and a rotating cylinder. The top of the support frame is provided with multiple guide rings, which are sleeved on the outside of the rotating cylinder through bearings. One end of the rotating cylinder is provided with a feed pipe. The outer periphery of the rotating cylinder is provided with a first discharge hole and a second discharge hole, and the outer periphery of the rotating cylinder is provided with two discharge mechanisms. The two discharge mechanisms are respectively connected to the first discharge hole and the second discharge hole.

[0028] The rotating cylinder is equipped with a drive frame, which includes a first turntable and a second turntable. The first turntable and the second turntable are movably connected to the two ends of the inner wall of the rotating cylinder. A grinding roller is provided between the first turntable and the second turntable, and the grinding roller is located at the bottom end of the inner wall of the rotating cylinder.

[0029] The top of the support frame is equipped with a motor frame, the top of the motor frame is equipped with a first motor and a fixed frame, the output end of the first motor is equipped with a reducer, the output shaft of the first motor is connected to the input shaft of the reducer, the output shaft of the reducer is connected to a gear shaft, the gear shaft passes through the fixed frame, the gear shaft is connected to a drive gear, the outside of the rotating cylinder is equipped with a gear ring, and the drive gear meshes with the gear ring.

[0030] In a preferred embodiment, the discharge mechanism includes a fixed sleeve that is movably fitted onto the outside of the rotating cylinder. The fixed sleeve is connected to the support frame via a connecting frame. The connection between the fixed sleeve and the rotating cylinder is in close contact. A discharge pipe is provided at the bottom of the fixed sleeve, and the discharge pipe communicates with the interior of the rotating cylinder. A valve is provided inside the discharge pipe.

[0031] In a preferred embodiment, both ends of the roller are provided with rotating shafts, which are rotatably connected to the interior of the first and second turntables.

[0032] The bottom of the inner wall of the rotating cylinder is adapted to the grinding roller;

[0033] The inner wall of the rotating cylinder and the surface of the grinding roller are both provided with protrusions;

[0034] The drive frame also includes a connecting shaft connected to the first turntable. The connecting shaft passes through the end of the rotating cylinder away from the feed pipe. The connecting shaft is connected to a limiting plate, which is located outside the rotating cylinder. Both the connecting shaft and the limiting plate are movably connected to the rotating cylinder. The limiting plate is connected to a second motor. The output shaft of the second motor is connected to a drive wheel. The rotating shaft inside the first turntable is equipped with a driven wheel. The drive wheel and the driven wheel are connected by a belt drive. The inner wall of the rotating cylinder is equipped with an inner ring. The inner ring has an L-shaped cross-section and communicates with the feed pipe. The inner ring is located on the inner circumference of the second turntable and is used to limit the position of the second turntable. The inner wall of the rotating cylinder is equipped with an outer ring, which is located on the outer circumference of the second turntable and is used to limit the position of the second turntable.

[0035] In a preferred embodiment, the inside of the grinding roller is hollow, and an oscillating frame is provided inside the grinding roller. The oscillating frame includes:

[0036] The roller has a first fixed shaft inside, which is coaxial with the axis of the roller. Multiple rotating sleeves are sleeved on the outside of the first fixed shaft. The rotating sleeves rotate around the first fixed shaft. The rotating sleeves are provided with connecting rods. A counterweight is provided at the end of the connecting rod away from the rotating sleeve. Multiple limiting blocks are provided on the inner wall of the roller, and each limiting block corresponds to one of the rotating sleeves.

[0037] or

[0038] The roller has a second fixed shaft inside, which is coaxial with the axis of the roller. The second fixed shaft has multiple guide sleeves, and a sliding rod is slidably connected inside the guide sleeve. The sliding rod passes through the guide sleeve, and there are impact blocks at both ends of the sliding rod. The inner wall of the roller has multiple pads, and the pads correspond one-to-one with the impact blocks.

[0039] This invention provides a method and system for removing mica from manufactured granite sand. By adopting the above solution, the following beneficial effects are achieved:

[0040] 1. First, the material is screened into coarse and fine particles. Then, through coarse particle air separation and fine particle magnetic separation, the mica content in the entire particle size of the manufactured sand can be effectively reduced to meet the requirements of national and industry standards for mica content ≤2%.

[0041] 2. By only performing air separation on coarse materials, the drawbacks of poor separation effect of fine particles, large loss of fine-grained manufactured sand, and increased fineness modulus of sand and gravel after separation can be effectively avoided. At the same time, the coarse material air separation process is simple, with less pollution, obvious separation effect, low dust removal pressure, and low cost.

[0042] 3. Magnetic separation is used only for fine materials, which not only has high separation accuracy, but also avoids the problem of large loss of mica-containing intergrowth particles caused by incomplete mica dissociation during coarse-grained magnetic separation, while effectively retaining fine stone powder. This helps to reduce the loss of manufactured sand.

[0043] 4. Before screening, the mica is kneaded to fully separate it from the sand and gravel, preventing them from sticking together. This facilitates subsequent screening and ensures the screening effect and the quality of the finished product.

[0044] 5. The process of kneading allows for the separation of coarse and fine materials, resulting in higher efficiency and reduced costs.

[0045] 6. Vibration during the kneading process allows for more thorough separation of the mica, increasing kneading efficiency and resulting in better separation. Attached Figure Description

[0046] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0047] Figure 1 This is a flowchart of a method and system for removing mica from granite manufactured sand according to the present invention;

[0048] Figure 2 This is a schematic diagram of the kneading device described in this invention;

[0049] Figure 3 This is a front view of the kneading device described in this invention;

[0050] Figure 4 This is a cross-sectional view of the kneading device described in this invention;

[0051] Figure 5 This is a cross-sectional view of an embodiment of the kneading device described in this invention;

[0052] Figure 6 This is a schematic diagram of the drive frame described in this invention;

[0053] Figure 7 This is a schematic diagram of an embodiment of the oscillator frame described in this invention;

[0054] Figure 8 This is a schematic diagram of an embodiment of the oscillator frame of the present invention;

[0055] Figure 9 This is a cross-sectional view of an embodiment of the kneading device of the present invention;

[0056] Figure 10 This is a schematic diagram of the structure at the connection between the rotating shaft and the first turntable of the present invention.

[0057] In the picture:

[0058] Linear vibrating screen 11, air drying chamber 12, air separator 13, magnetic separator 14, drying unit 15, dewatering screen 16, mixing equipment 17;

[0059] Support frame 2, guide ring 201, bearing 202, rotating cylinder 3, first discharge hole 301, second discharge hole 302, feed pipe 303, motor frame 401, first motor 402, reducer 403, fixed frame 404, gear shaft 405, drive gear 406, gear ring 407, fixed sleeve 501, connecting frame 502, discharge pipe 503, valve 504, drive frame 6, first turntable 601, connecting shaft 602 Limiting disc 603, second motor 604, driving wheel 605, driven wheel 606, belt 607, second turntable 608, inner ring 609, outer ring 610, grinding roller 7, rotating shaft 701, vibrating frame 8, first fixed shaft 811, rotating sleeve 812, connecting rod 813, counterweight block 814, limiting block 815, second fixed shaft 821, guide sleeve 822, sliding rod 823, impact block 824, pad 825. Detailed Implementation

[0060] Example 1:

[0061] Mineral phase analysis showed that the main mineral components of this granite were plagioclase, quartz, potassium feldspar, amphibole, and mica, with mica accounting for about 8%. The contents of each component are shown in Table 1.

[0062]

[0063] Table 1 - Mineral Composition of Granite

[0064] The mica content of the semi-finished manufactured sand obtained from the crushing system was tested using the mica content test method provided in the national standard GB / T 14684 "Construction Sand". The mica content in the manufactured sand raw material was found to be 13.45%.

[0065] Further sieve analysis of the raw material, manufactured sand, determined its modulus to be 2.63, classifying it as Zone 2 manufactured sand according to the national standard GB / T14684 "Construction Sand". The specific sieve residues for each particle size and the cumulative sieve residues are shown in Table 2.

[0066]

[0067] Table 2 - Particle size distribution and modulus of raw sand and gravel

[0068] To effectively remove mica and produce manufactured sand that meets particle size distribution requirements, such as Figure 1 As shown, the specific implementation method includes the following steps:

[0069] S1. The semi-finished manufactured sand obtained from the crushing system is kneaded and then screened and graded to obtain coarse sand and fine sand;

[0070] S2. The coarse sand obtained in S1 is screened and the flaky mica is removed by air classification to obtain heavy product and light product.

[0071] S3. The undersize sand obtained in S1 is subjected to high-gradient wet magnetic separation to remove the weakly magnetic fine mica, resulting in non-magnetic and magnetic products.

[0072] S4. Combine the heavy product from S2 with the non-magnetic product from S3 to obtain fully-sized manufactured sand with a mica content of <2%.

[0073] Preferably, the sieve aperture used for screening and grading in step S1 is 1.18 mm.

[0074] The wind speed in step S2 is 6 m / s.

[0075] The magnetic field strength for magnetic separation in step S3 is 16000 Oe.

[0076] In step S3, the magnetic product is dried by the drying unit, and the non-magnetic product is dehydrated by the dehydration screen.

[0077] In step S4, the heavy product and the non-magnetic product are mixed by a mixing device to obtain fully graded manufactured sand with a gradation that meets the specifications.

[0078] After sorting, the mica content in the manufactured sand was measured to be 0.67% according to the national standard GB / T 14684 "Construction Sand". The sand and gravel product rate was 54.54%, and the modulus was 2.67, which meets the particle size distribution requirements of Zone 2 manufactured sand in the national standard GB / T 14684 "Construction Sand". The sieve residue of each particle size and the cumulative sieve residue are shown in Table 3.

[0079]

[0080] Table 3 - Particle size distribution and modulus of sand and gravel after sorting in Example 1

[0081] As can be seen from the table above, after grading and sorting, the mica content of the manufactured sand is reduced to ≤2%, and the overall modulus does not change much compared with the raw material. It still meets the particle size distribution requirements of Zone 2 manufactured sand in the national standard. The raw material can be used as qualified manufactured sand after being separated and sorted, avoiding the cumbersome steps of manufactured sand blending.

[0082] Example 2:

[0083] Repeat the steps in Example 1, except that the magnetic field strength of the magnetic separation in step S3 is 13000 Oe.

[0084] After sorting, the obtained manufactured sand has a mica content of 1.48%, a sand and gravel product rate of 65.47%, and a modulus of 2.57, which meets the requirements of particle size distribution for Zone 2 manufactured sand in the national standard GB / T 14684 "Construction Sand". The sieve residue of each particle size and the cumulative sieve residue are shown in Table 4.

[0085]

[0086] Table 4 - Particle size distribution and modulus of sand and gravel after sorting in Example 2

[0087] Example 3:

[0088] Repeat the steps in Example 1, except that the wind speed in step S2 is 4 m / s.

[0089] After sorting, the obtained manufactured sand has a mica content of 0.68%, a sand and gravel product rate of 58.97%, and a modulus of 2.78, which meets the requirements of particle size distribution for Zone 2 manufactured sand in the national standard GB / T 14684 "Construction Sand". The sieve residue of each particle size and the cumulative sieve residue are shown in Table 5.

[0090]

[0091] Table 5 - Particle size distribution and modulus of sand and gravel after sorting in Example 3

[0092] Example 4:

[0093] Repeat the steps in Example 1, except that the wind speed in step S2 is 4 m / s and the magnetic field strength in step S3 is 13000 Oe.

[0094] After sorting, the obtained manufactured sand has a mica content of 1.42%, a sand and gravel product rate of 69.91%, and a modulus of 2.66, which meets the requirements of particle size distribution for Zone 2 manufactured sand in the national standard GB / T 14684 "Construction Sand". The sieve residue of each particle size and the cumulative sieve residue are shown in Table 6.

[0095]

[0096] Table 6 - Particle size distribution and modulus of sand and gravel after sorting in Example 4

[0097] As can be seen from the above embodiments, the mica removal method provided by the present invention can effectively reduce the biotite content in granite manufactured sand, ensuring that the produced manufactured sand gradation meets the requirements of the specifications while meeting the requirement that the mica content is ≤2%. The advantages of the mica removal method provided by the present invention are its simple process, significant effect, energy saving and environmental protection, and good production and economic benefits.

[0098] The technical principle of this invention is to organically combine the different occurrence characteristics of mica in coarse and fine materials with the respective separation advantages of gravity and magnetic separation to achieve efficient removal of mica from all particle sizes of sand and gravel. Specifically, air separation utilizes the characteristic that mica is broken and dissociated into flakes in the coarse particle size. Under horizontal wind conditions, mica has high wind resistance and is easily blown away, thus achieving separation from heavier sand and gravel. Magnetic separation utilizes the characteristic that mica has weak magnetism and is fully dissociated in the fine particle size. Under high gradient magnetic field conditions, it achieves separation from non-magnetic sand and gravel. Furthermore, the semi-finished manufactured sand is kneaded before screening to treat the adhered mica-sand and gravel material, separating the mica from the sand and gravel, and then screening to ensure the screening effect.

[0099] Example 5:

[0100] like Figure 1 and 2 As shown, a system for removing mica from granite manufactured sand is characterized by comprising a primary screening mechanism and two secondary screening mechanisms. The primary screening mechanism is used to screen coarse sand and fine sand, and the two secondary screening mechanisms are used to screen the coarse sand and fine sand obtained by the primary screening mechanism.

[0101] The primary screening mechanism includes a kneading device for kneading semi-finished manufactured sand to facilitate the separation of mica.

[0102] By kneading the semi-finished manufactured sand and then screening it, the adhering mica-sand and gravel materials can be treated, separating the mica from the sand and gravel, and then screening is carried out to ensure the screening effect.

[0103] In the preferred embodiment, the secondary screening mechanism includes an air separator 13 and a magnetic separator 14. The air separator 13 is equipped with a drying chamber 12 at its feed end, and the magnetic separator 14 is equipped with a drying unit 15 and a dewatering screen 16 at its discharge end. The drying unit 15 is used to dry magnetic products, and the dewatering screen 16 is used to process non-magnetic products. The drying chamber 12, air separator 13, magnetic separator 14, drying unit 15, and dewatering screen 16 can all be existing equipment. The method of this application is followed by control using existing methods.

[0104] The products separated by the air classifier 13 and the non-magnetic products are mixed by the mixing equipment 17. The mixing equipment 17 can be any existing equipment. The method of this application is followed by control using existing methods.

[0105] Example 6:

[0106] like Figure 2 , 3 As shown in Figures 6 and 9, the primary screening mechanism also includes a linear vibrating screen 11. The linear vibrating screen 11 can be made using existing equipment. The linear vibrating screen 11 is used to screen the products processed by the kneading equipment.

[0107] The kneading equipment includes a support frame 2 and a rotating cylinder 3. The top of the support frame 2 is provided with multiple guide rings 201. The guide rings 201 are sleeved on the outside of the rotating cylinder 3 through bearings 202. One end of the rotating cylinder 3 is provided with a feed pipe 303. The outer circumferential surface of the rotating cylinder 3 is provided with a first discharge hole 301 and a discharge mechanism.

[0108] In this embodiment, only one first discharge hole 301 is provided. The diameter of the first discharge hole 301 is larger than the particle diameter of the coarse manufactured sand. After the kneading is completed, the material is discharged through the first discharge hole 301 and the discharge mechanism. Then, the kneaded manufactured sand is transported to the linear vibrating screen 11 for screening into coarse and fine sand.

[0109] The rotating cylinder 3 is equipped with a drive frame 6, which includes a first turntable 601 and a second turntable 608. The first turntable 601 and the second turntable 608 are movably connected to the two ends of the inner wall of the rotating cylinder 3. A grinding roller 7 is provided between the first turntable 601 and the second turntable 608. The grinding roller 7 is located at the bottom end of the inner wall of the rotating cylinder 3. Under the action of its own weight, the grinding roller 7 will drive the first turntable 601 and the second turntable 608 to rotate relative to the rotating cylinder 3, so that the grinding roller 7 always moves within the range of the bottom end of the inner wall of the rotating cylinder 3, so as to knead the manufactured sand.

[0110] The top of the support frame 2 is provided with a motor frame 401, and the top of the motor frame 401 is provided with a first motor 402 and a fixed frame 404. The first motor 402 can be any existing type, such as a geared motor, a three-phase motor or a servo motor, and is controlled by existing technology. The output end of the first motor 402 is provided with a reducer 403. The output shaft of the first motor 402 is connected to the input shaft of the reducer 403. The output shaft of the reducer 403 is connected to a gear shaft 405. The gear shaft 405 passes through the fixed frame 404 and is connected to a drive gear 406. The outside of the rotating cylinder 3 is provided with a gear ring 407. The drive gear 406 meshes with the gear ring 407.

[0111] In use, manufactured sand is fed into the rotating drum 3 through the feed pipe 303 using existing methods (such as auger conveyor and elevator). Then, the first motor 402 is started, which drives the gear shaft 405 to rotate through the reducer 403, thereby driving the drive gear 406 to rotate, which in turn drives the gear ring 407 to rotate, and finally drives the rotating drum 3 to rotate. During the rotation of the rotating drum 3, the manufactured sand inside the rotating drum 3 will move along with it. At the same time, the grinding roller 7 continuously crushes and rubs the manufactured sand, which can separate the mica and gravel adhering in the manufactured sand, so as to facilitate subsequent screening.

[0112] Since the roller 7 always moves within the bottom range of the inner wall of the rotating cylinder 3, the roller 7 moves relative to the rotating cylinder 3 when the rotating cylinder 3 rotates, so as to complete the kneading of the manufactured sand.

[0113] After the kneading is completed, the material is discharged through the first discharge hole 301 and the discharge mechanism, and then the next step can be carried out.

[0114] Example 7:

[0115] like Figure 2 , 3 As shown in Figures 4, 5, and 6, the kneading device includes a support frame 2 and a rotating cylinder 3. The top of the support frame 2 is provided with multiple guide rings 201, which are sleeved on the outside of the rotating cylinder 3 through bearings 202. One end of the rotating cylinder 3 is provided with a feed pipe 303. The outer periphery of the rotating cylinder 3 is provided with a first discharge hole 301 and a second discharge hole 302, and the outer periphery of the rotating cylinder 3 is provided with two discharge mechanisms. The two discharge mechanisms are respectively connected to the first discharge hole 301 and the second discharge hole 302.

[0116] In this embodiment, the linear vibrating screen 11 is no longer used. Instead, after kneading, fine sand is directly screened out through the second discharge hole 302, and then coarse sand is discharged through the first discharge hole 301. There is no need to set up a separate vibrating screen, which saves costs.

[0117] The rotating cylinder 3 is equipped with a drive frame 6, which includes a first turntable 601 and a second turntable 608. The first turntable 601 and the second turntable 608 are movably connected to the two ends of the inner wall of the rotating cylinder 3. A grinding roller 7 is provided between the first turntable 601 and the second turntable 608. The grinding roller 7 is located at the bottom end of the inner wall of the rotating cylinder 3. Under the action of its own weight, the grinding roller 7 will drive the first turntable 601 and the second turntable 608 to rotate relative to the rotating cylinder 3, so that the grinding roller 7 always moves within the range of the bottom end of the inner wall of the rotating cylinder 3, so as to knead the manufactured sand.

[0118] The top of the support frame 2 is provided with a motor frame 401, the top of the motor frame 401 is provided with a first motor 402 and a fixed frame 404, the output end of the first motor 402 is provided with a reducer 403, the output shaft of the first motor 402 is connected to the input shaft of the reducer 403, the output shaft of the reducer 403 is connected to a gear shaft 405, the gear shaft 405 passes through the fixed frame 404, the gear shaft 405 is connected to a drive gear 406, the outside of the rotating cylinder 3 is provided with a gear ring 407, and the drive gear 406 meshes with the gear ring 407.

[0119] In use, manufactured sand is fed into the rotating drum 3 through the feed pipe 303 using existing methods (such as auger conveyor and elevator). Then, the first motor 402 is started, which drives the gear shaft 405 to rotate through the reducer 403, thereby driving the drive gear 406 to rotate, which in turn drives the gear ring 407 to rotate, and finally drives the rotating drum 3 to rotate. During the rotation of the rotating drum 3, the manufactured sand inside the rotating drum 3 will move along with it. At the same time, the grinding roller 7 continuously crushes and rubs the manufactured sand, which can separate the mica and gravel adhering in the manufactured sand, so as to facilitate subsequent screening.

[0120] Since the roller 7 always moves within the bottom range of the inner wall of the rotating cylinder 3, the roller 7 moves relative to the rotating cylinder 3 when the rotating cylinder 3 rotates, so as to complete the kneading of the manufactured sand.

[0121] After kneading, fine sand is first discharged through the second discharge hole 302 and the discharge mechanism, and then coarse sand is discharged through the first discharge hole 301 and the discharge mechanism before proceeding to the next step. The operation is simple, and screening is completed while kneading, which increases efficiency and reduces costs.

[0122] In the above embodiments, as shown in 2, 4, 5 and 9, the discharge mechanism includes a fixed sleeve 501 that is movably sleeved on the outside of the rotating cylinder 3. The fixed sleeve 501 is connected to the support frame 2 through a connecting frame 502. The connection between the fixed sleeve 501 and the rotating cylinder 3 is in close contact. The bottom of the fixed sleeve 501 is provided with a discharge pipe 503, which communicates with the interior of the rotating cylinder 3. A valve 504 is provided inside the discharge pipe 503, and the valve 504 is preferably an existing gate valve.

[0123] During kneading, valve 504 is closed, and the manufactured sand is kneaded inside the rotating drum 3. The manufactured sand that enters the first discharge hole 301 and the second discharge hole 302 will fall naturally under the action of gravity when the rotating drum 3 rotates to the top, without affecting the overall kneading effect. When it is necessary to discharge the material, open the valve 504 corresponding to the second discharge hole 302 to discharge fine sand. After the fine sand is discharged, open the valve 504 corresponding to the first discharge hole 301 to discharge coarse sand. The operation is simple and the material is easy to discharge.

[0124] The size of the first discharge hole 301 ensures that coarse material can pass through smoothly, while the size of the second discharge hole 302 is determined according to actual needs. For example, if the diameter boundary between fine sand and coarse sand is defined as 1 mm, then the diameter of the second discharge hole 302 is 1 mm.

[0125] Example 8:

[0126] like Figure 4 , 5 As shown in Figure 6, both ends of the roller 7 are provided with rotating shafts 701, which are rotatably connected to the interior of the first turntable 601 and the second turntable 608.

[0127] The bottom of the inner wall of the rotating cylinder 3 is adapted to the grinding roller 7; as needed, such as Figure 4 As shown, the roller 7 can be cylindrical; or, for example... Figure 5 As shown, the middle part of the roller 7 is cylindrical and the two ends are frustum-shaped. The inner wall of the rotating cylinder 3 is adapted to the roller 7, so that the machine sand in the rotating cylinder 3 gathers in the middle, which facilitates the discharge.

[0128] The inner wall of the rotating cylinder 3 and the surface of the roller 7 are both provided with protrusions to enhance the kneading effect;

[0129] The drive frame 6 also includes a connecting shaft 602 connected to the first turntable 601. The connecting shaft 602 passes through the end of the rotating cylinder 3 away from the feed pipe 303. The connecting shaft 602 is connected to a limiting disk 603, which is located outside the rotating cylinder 3. Both the connecting shaft 602 and the limiting disk 603 are movably connected to the rotating cylinder 3. The limiting disk 603 is connected to a second motor 604, which is preferably an existing motor, such as a servo motor or a stepper motor. The output shaft of the second motor 604 is connected to a drive wheel 605. The rotating shaft 701 located inside the first turntable 601 is provided with a driven wheel. Wheel 606, drive wheel 605 and driven wheel 606 are connected by belt 607. Belt 607 is preferably an elastic belt. There are transmission teeth between belt 607 and drive wheel 605 and driven wheel 606. The inner wall of rotating cylinder 3 is provided with inner ring 609. The cross-section of inner ring 609 is L-shaped. Inner ring 609 is connected to feed pipe 303. Inner ring 609 is located on the inner circumference of second turntable 608 and is used to limit the position of second turntable 608. The inner wall of rotating cylinder 3 is provided with outer ring 610. Outer ring 610 is located on the outer circumference of second turntable 608 and is used to limit the position of second turntable 608.

[0130] During kneading, the second motor 604 is started to drive the drive wheel 605 to rotate, which in turn drives the driven wheel 606 to rotate via the belt 607. This drives the rotating shaft 701 and the roller 7 to rotate, so that the roller 7 rotates relative to the rotating cylinder 3, which increases the kneading effect and ensures the kneading quality. Preferably, the roller 7 rotates in the opposite direction to the rotating cylinder 3.

[0131] If necessary, the belt drive can also be replaced with a gear drive, depending on the actual situation.

[0132] Example 9:

[0133] like Figure 7 As shown, the inside of the grinding roller 7 is hollow, and an oscillating frame 8 is provided inside the grinding roller 7. The oscillating frame 8 includes:

[0134] The roller 7 is provided with a first fixed shaft 811, which is coaxial with the axis of the roller 7. Multiple rotating sleeves 812 are sleeved on the outside of the first fixed shaft 811. Existing bearings are provided between the rotating sleeves 812 and the first fixed shaft 811. The rotating sleeves 812 rotate around the first fixed shaft 811. The rotating sleeves 812 are provided with connecting rods 813. A counterweight block 814 is provided at the end of the connecting rod 813 away from the rotating sleeves 812. Multiple limiting blocks 815 are provided on the inner wall of the roller 7. The limiting blocks 815 correspond one-to-one with the rotating sleeves 812.

[0135] During the rotation of the roller 7, the first fixed shaft 811 and the limiting block 815 will rotate. When the limiting block 815 rotates to below the first fixed shaft 811, it will push the counterweight 814 to rotate with it. When the counterweight 814 is pushed to the upper limit position, it will move rapidly downward under the action of gravity after passing the upper limit position. At this time, the counterweight 814 will drive the connecting rod 813 and the rotating sleeve 812 to rotate around the first fixed shaft 811 to the lower limit position and swing under the action of potential energy. During this process, the potential energy will act on the first fixed shaft 811 and then act on the roller 7 through the first fixed shaft 811, causing the roller 7 to oscillate, thereby enhancing the kneading effect on the manufactured sand.

[0136] Example 10:

[0137] like Figure 8 As shown, the inside of the grinding roller 7 is hollow, and an oscillating frame 8 is provided inside the grinding roller 7. The oscillating frame 8 includes:

[0138] The roller 7 is provided with a second fixed shaft 821, which is coaxial with the axis of the roller 7. The second fixed shaft 821 is provided with multiple guide sleeves 822. A sliding rod 823 is slidably connected inside the guide sleeve 822. The sliding rod 823 passes through the guide sleeve 822. Impact blocks 824 are provided at both ends of the sliding rod 823. The inner wall of the roller 7 is provided with multiple pads 825, and the pads 825 correspond one-to-one with the impact blocks 824.

[0139] During the rotation of the roller 7, the second fixed shaft 821, guide sleeve 822 and pad 825 will rotate, thereby driving the sliding rod 823 and impact block 824 to rotate. When the sliding rod 823 rotates to the vertical position, it can slide downward under the action of the gravity of the impact block 824 and finally hit the pad 825. The impact force generated by the impact will act on the roller 7, causing the roller 7 to vibrate, thereby enhancing the kneading effect on the manufactured sand.

[0140] In a further embodiment, such as Figure 10 As shown, in order to ensure the normal operation of oscillation in Embodiments 9 and 10, an existing bearing is provided on the outside of the rotating shaft 701, and an elastic rubber sleeve is provided between the bearing and the first turntable 601 or the second turntable 608. In order to ensure normal rotation, the roller 7 will compress the elastic rubber sleeve when it oscillates, so that the oscillation of the roller 7 will not be restricted by the first turntable 601 or the second turntable 608, thus ensuring the normal operation of oscillation.

[0141] The mica referred to in this invention includes, but is not limited to, biotite, and the screened manufactured sand includes, but is not limited to, granite manufactured sand. Granite manufactured sand should not be construed as a limitation of this application.

[0142] The above embodiments are merely preferred technical solutions of the present invention and should not be considered as limitations on the present invention. The scope of protection of the present invention should be limited to the technical solutions described in the claims, including equivalent substitutions of the technical features described in the claims. That is, equivalent substitutions and improvements within this scope are also within the scope of protection of the present invention.

Claims

1. A system for removing mica from manufactured granite sand, characterized in that: It includes a primary screening mechanism and two secondary screening mechanisms. The primary screening mechanism is used to screen coarse sand and fine sand, and the two secondary screening mechanisms are used to screen the coarse sand and fine sand obtained by the primary screening mechanism. The primary screening mechanism includes a kneading device for kneading semi-finished manufactured sand to facilitate the separation of mica; The primary screening mechanism also includes a linear vibrating screen (11), which is used to screen the products processed by the kneading equipment; The kneading equipment includes a support frame (2) and a rotating cylinder (3). The top of the support frame (2) is provided with multiple guide rings (201). The guide rings (201) are sleeved on the outside of the rotating cylinder (3) through bearings (202). One end of the rotating cylinder (3) is provided with a feed pipe (303). The outer circumferential surface of the rotating cylinder (3) is provided with a first discharge hole (301) and a discharge mechanism. The rotating cylinder (3) is provided with a drive frame (6), which includes a first turntable (601) and a second turntable (608). The first turntable (601) and the second turntable (608) are movably connected to the two ends of the inner wall of the rotating cylinder (3). A grinding roller (7) is provided between the first turntable (601) and the second turntable (608). The grinding roller (7) is located at the bottom end of the inner wall of the rotating cylinder (3). The top of the support frame (2) is provided with a motor frame (401), the top of the motor frame (401) is provided with a first motor (402) and a fixed frame (404), the output end of the first motor (402) is provided with a reducer (403), the output shaft of the first motor (402) is connected to the input shaft of the reducer (403), the output shaft of the reducer (403) is connected to a gear shaft (405), the gear shaft (405) passes through the fixed frame (404), the gear shaft (405) is connected to a drive gear (406), the outside of the rotating cylinder (3) is provided with a gear ring (407), the drive gear (406) meshes with the gear ring (407); The inside of the grinding roller (7) is hollow, and an oscillating frame (8) is provided inside the grinding roller (7). The oscillating frame (8) includes: The roller (7) is provided with a first fixed shaft (811), which is coaxial with the axis of the roller (7). Multiple rotating sleeves (812) are sleeved on the outside of the first fixed shaft (811). The rotating sleeves (812) rotate around the first fixed shaft (811). The rotating sleeves (812) are provided with connecting rods (813). A counterweight (814) is provided at the end of the connecting rod (813) away from the rotating sleeves (812). Multiple limiting blocks (815) are provided on the inner wall of the roller (7). The limiting blocks (815) correspond one-to-one with the rotating sleeves (812). or The roller (7) is provided with a second fixed shaft (821), which is coaxial with the axis of the roller (7). The second fixed shaft (821) is provided with multiple guide sleeves (822), and a sliding rod (823) is slidably connected inside the guide sleeve (822). The sliding rod (823) passes through the guide sleeve (822), and impact blocks (824) are provided at both ends of the sliding rod (823). The inner wall of the roller (7) is provided with multiple pads (825), and the pads (825) correspond one-to-one with the impact blocks (824).

2. The system for removing mica from manufactured granite sand according to claim 1, characterized in that: The secondary screening mechanism includes an air separator (13) and a magnetic separator (14). The air separator (13) has a drying chamber (12) at its feed end and a drying unit (15) and a dewatering screen (16) at its discharge end. The drying unit (15) is used to dry magnetic products and the dewatering screen (16) is used to process non-magnetic products. The air classifier (13) mixes the air-classified products with the non-magnetic products through the mixing equipment (17).

3. The system for removing mica from manufactured granite sand according to claim 2, characterized in that: The kneading equipment includes a support frame (2) and a rotating cylinder (3). The top of the support frame (2) is provided with multiple guide rings (201). The guide rings (201) are sleeved on the outside of the rotating cylinder (3) through bearings (202). One end of the rotating cylinder (3) is provided with a feed pipe (303). The outer periphery of the rotating cylinder (3) is provided with a first discharge hole (301) and a second discharge hole (302). The outer periphery of the rotating cylinder (3) is provided with two discharge mechanisms. The two discharge mechanisms are respectively connected to the first discharge hole (301) and the second discharge hole (302). The rotating cylinder (3) is provided with a drive frame (6), which includes a first turntable (601) and a second turntable (608). The first turntable (601) and the second turntable (608) are movably connected to the two ends of the inner wall of the rotating cylinder (3). A grinding roller (7) is provided between the first turntable (601) and the second turntable (608). The grinding roller (7) is located at the bottom end of the inner wall of the rotating cylinder (3). The top of the support frame (2) is provided with a motor frame (401), the top of the motor frame (401) is provided with a first motor (402) and a fixed frame (404), the output end of the first motor (402) is provided with a reducer (403), the output shaft of the first motor (402) is connected to the input shaft of the reducer (403), the output shaft of the reducer (403) is connected to a gear shaft (405), the gear shaft (405) passes through the fixed frame (404), the gear shaft (405) is connected to a drive gear (406), the outside of the rotating cylinder (3) is provided with a gear ring (407), and the drive gear (406) meshes with the gear ring (407).

4. A system for removing mica from manufactured granite sand according to any one of claims 1 or 3, characterized in that: The discharge mechanism includes a fixed sleeve (501) that is movably sleeved on the outside of the rotating cylinder (3). The fixed sleeve (501) is connected to the support frame (2) through the connecting frame (502). The connection between the fixed sleeve (501) and the rotating cylinder (3) is in close contact. The bottom of the fixed sleeve (501) is provided with a discharge pipe (503), which is connected to the inside of the rotating cylinder (3). A valve (504) is provided inside the discharge pipe (503).

5. A system for removing mica from manufactured granite sand according to any one of claims 1 or 3, characterized in that: Both ends of the roller (7) are provided with rotating shafts (701), which are rotatably connected to the inside of the first turntable (601) and the second turntable (608); The bottom of the inner wall of the rotating cylinder (3) is adapted to the grinding roller (7); The inner wall of the rotating cylinder (3) and the surface of the roller (7) are both provided with protrusions; The drive frame (6) also includes a connecting shaft (602) connected to the first turntable (601). The connecting shaft (602) passes through one end of the rotating cylinder (3) away from the feed pipe (303). The connecting shaft (602) is connected to a limiting plate (603), which is located outside the rotating cylinder (3). The connecting shaft (602) and the limiting plate (603) are both movably connected to the rotating cylinder (3). The limiting disk (603) is connected to the second motor (604), the output shaft of the second motor (604) is connected to the driving wheel (605), the rotating shaft (701) located in the first turntable (601) is provided with the driven wheel (606), the driving wheel (605) and the driven wheel (606) are connected by a belt (607); the inner wall of the rotating cylinder (3) is provided with an inner ring (609), the cross section of the inner ring (609) is L-shaped, the inner ring (609) is connected to the feed pipe (303), the inner ring (609) is located on the inner circumference of the second turntable (608), and is used to limit the position of the second turntable (608); the inner wall of the rotating cylinder (3) is provided with an outer ring (610), the outer ring (610) is located on the outer circumference of the second turntable (608), and is used to limit the position of the second turntable (608).

6. A method for removing mica from manufactured granite sand, characterized in that: A system for removing mica from granite manufactured sand according to any one of claims 1-5 includes the following steps: S1. Knead the semi-finished machine-made sand and sieve and classify it to obtain coarse sand and fine sand; S2. Remove the flaky mica from the coarse sand by air classification to obtain heavy and light products; S3. Fine sand is subjected to high-gradient wet magnetic separation to remove weakly magnetic micro-mica, resulting in non-magnetic and magnetic products. S4. Combine heavy products with non-magnetic products to obtain fully-sized manufactured sand with a mica content of <2%.

7. The method for removing mica from manufactured granite sand according to claim 6, characterized in that, In step S2, the coarse sand obtained from screening is air-dried and then air-separated at a wind speed of 2~10m / s.

8. The method for removing mica from manufactured granite sand according to claim 6, characterized in that, The magnetic field strength for magnetic separation in step S3 is 10000~20000 Oe; In step S3, the non-magnetic product after magnetic separation is dehydrated by a dehydration screen, and the magnetic product is dried by a drying unit.

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