Method and system for removing mica from granite machine-made sand

Abstract

The invention 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, the coarse sand is subjected to winnowing to remove flaky mica, and a heavy product and a light product are obtained; s3, fine mica with weak magnetism is removed from the fine sand through high-gradient wet magnetic separation, and a non-magnetic product and a magnetic product are obtained; s4, combining the heavy product with the non-magnetic product to obtain the mica content lt; and 2% of full-size machine-made sand. According to the method and system for removing mica from granite machine-made sand, the coarse material and the fine material are screened firstly, then through coarse material winnowing and fine material magnetic separation, the mica content in the whole size fraction of the machine-made sand can be effectively reduced, and the requirement that the mica content is smaller than or equal to 2% in the national standard and the industrial standard is met; and the mica is rubbed before screening, so that the mica is fully separated from sand and gravel materials, adhesion is avoided, subsequent screening can be facilitated, and the screening effect and the quality of screened finished products are guaranteed.

Description

Technical Field

[0001] The invention relates to the technical field of machine-made sand processing, and in particular to a method and system for removing mica from machine-made granite sand. Background Art

[0002] Sand and gravel are important raw materials for infrastructure such as construction, water conservancy, roads, bridges, and municipal construction. With the sustained and rapid development of my country's infrastructure, the limited natural sand resources in many regions have been almost exhausted. In order to meet engineering needs and environmental protection requirements, machine-made sand has gradually replaced natural sand as the main raw material for concrete. Currently, many hydropower projects basically use local materials and use excavated rocks to produce artificial aggregates. Mica is often found in the parent rock of sand and gravel raw materials such as granite and marble;

[0003] Among them, in the process of using granite to produce machine-made sand, the crushing operation will dissociate and release mica particles. If effective mica removal measures are not taken, the mica particles will eventually enter the finished sand. Mica with a layered structure has low strength and poor adhesion to cement slurry. A large number of studies have shown that when the content of mica in machine-made sand exceeds a certain limit, the strength and durability of the machine-made sand will be significantly reduced, seriously affecting the compressive strength and tensile strength of concrete. Therefore, both national standards and industry standards clearly limit the mica content in sand to no more than 2%, such as "Construction Sand" GB / T 14684 and "Specifications for Hydraulic Concrete Construction" DL / T 5144. In this context, when using granite with a high mica content to produce machine-made sand, choosing a suitable mica removal method becomes the key to determining the quality of the finished sand.

[0004] Traditional methods for removing mica from machine-made sand mainly include air separation, magnetic separation and wet screening. The principle of air separation is that mica is flaky in structure, and when crushed, it will separate and peel off along its cleavage plane to present flaky shape. The lightweight flaky mica is separated from the heavier sand and gravel by applying a horizontal wind field. The advantages of air separation are simple principle and low cost, and the disadvantages are poor sorting accuracy for fine-grained materials. The finer the material, the smaller the difference in shape. Mica is usually enriched in fine-grained machine-made sand. For fine-grained materials, it is difficult for airflow to effectively distinguish particles of different densities or shapes. Removing mica will cause the loss of fine-grained machine-made sand, and the fineness modulus of the machine-made sand after selection will increase. The magnetic separation method is mainly for magnetic mica such as biotite and iron-containing mica, and uses the difference in magnetism between mica and sand and gravel for sorting. The advantage is that the sorting effect is obvious, especially for fine-grained materials, because the finer the particle size, the more complete the dissociation of mica and the higher the sorting accuracy, but for For coarse materials, since the inclusions or intergrowths formed by the incomplete dissociation of mica have certain magnetism, these intergrowths will be removed together with the mica, which will not only cause the waste of sand and gravel, but also reduce the fineness modulus of the machine-made sand after selection; the wet screening method mainly uses the characteristics of mica's light texture and flaky structure in the water medium, and uses a spiral chute to preliminarily sort out the mica. For the wastewater containing sand, the mica is screened out by screening to recover the fine sand and gravel powder. Although the principle of this method is simple and easy to operate, it consumes a lot of water. It has a good selection effect for muscovite, potassium mica, sericite and other mica with lighter specific gravity, but it is difficult to sort out biotite and other mica with heavier specific gravity.

[0005] In summary, the existing methods for removing mica from machine-made sand have the problems of difficulty in achieving efficient sorting of all particle sizes, unreasonable grading of sand and gravel after sorting, waste of resources, and low efficiency. Therefore, it is urgent to seek a new method for removing mica from machine-made sand with high mica content in granite, which can effectively reduce the mica content in the sand and produce sand and gravel aggregates with grading that meets the requirements of the specification.

[0006] In addition, the existing methods directly screen the machine-made sand. However, the machine-made sand still contains a lot of mica-sand and gravel adhesions. The mica-sand and gravel adhesions will be mixed in the finished machine-made sand and cannot be screened out. The mica removal effect is poor, which affects the quality of the finished machine-made sand. Summary of the invention

[0007] The main purpose of the present invention is to provide a method and system for removing mica from granite machine-made sand, so as to solve the problem that the existing mica removal method in machine-made sand is difficult to achieve efficient sorting of all particle sizes and has poor sorting effect.

[0008] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0009] A method for removing mica from granite machine-made sand comprises the following steps:

[0010] S1. Screening and grading the semi-finished machine-made sand to obtain coarse sand and fine sand;

[0011] S2, removing flaky mica from the coarse sand by air separation to obtain heavy products and light products;

[0012] S3, removing the fine mica with weak magnetism from the fine sand by high gradient wet magnetic separation to obtain non-magnetic products and magnetic products;

[0013] S4. The heavy product is combined with the non-magnetic product to obtain full-grained machine-made sand with a mica content of <2%.

[0014] In a preferred embodiment, the mesh size of the sieve used for screening and grading in step S1 is 0.8 to 1.5 mm.

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

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

[0017] In a 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, the heavy product and the non-magnetic product in step S4 are mixed by a mixing device to obtain a full-grade machine-made sand with a gradation that meets the requirements of the specification.

[0019] A system for removing mica from granite machine-made sand, comprising a primary screening mechanism and two secondary screening mechanisms, wherein 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 first-stage screening mechanism includes a kneading device for kneading the semi-finished machine-made sand to facilitate the separation of mica.

[0021] In a preferred solution, the secondary screening mechanism includes an air separator and a magnetic separator. The feed end of the air separator is provided with an air drying bin, and the discharge end of the magnetic separator is provided with a drying unit and a dehydration screen. The drying unit is used to dry the magnetic product, and the dehydration screen is used to process the non-magnetic product.

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

[0023] In a preferred solution, the first-level screening mechanism further includes a linear vibrating screen, which is used to screen the product processed by the kneading device;

[0024] The kneading device includes a support frame and a rotating cylinder. The top of the support frame is provided with a plurality of guide rings, which are sleeved on the outside of the rotating cylinder through bearings. A feed pipe is provided at one end of the rotating cylinder, and a first discharge hole and a discharge mechanism are provided on the outer peripheral surface of the rotating cylinder.

[0025] A driving frame is arranged in the rotating drum, and the driving frame includes a first rotating disk and a second rotating disk, and the first rotating disk and the second rotating disk are movably connected to the two ends of the inner wall of the rotating drum, and a grinding roller is arranged between the first rotating disk and the second rotating disk, and the grinding roller is located at the bottom end of the inner wall of the rotating drum;

[0026] A motor frame is provided on the top of the support frame, a first motor and a fixed frame are provided on the top of the motor frame, a reducer is provided at the output end of the first motor, 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 driving gear, a gear ring is provided on the outside of the rotating cylinder, and the driving gear is meshed with the gear ring.

[0027] In a preferred embodiment, the kneading device includes a support frame and a rotating drum, a plurality of guide rings are provided on the top of the support frame, the guide rings are sleeved on the outside of the rotating drum through bearings, a feed pipe is provided at one end of the rotating drum; a first discharge hole and a second discharge hole are provided on the outer periphery of the rotating drum, and two discharge mechanisms are provided on the outer periphery of the rotating drum; the two discharge mechanisms are connected to the first discharge hole and the second discharge hole respectively;

[0028] A driving frame is arranged in the rotating drum, and the driving frame includes a first rotating disk and a second rotating disk, and the first rotating disk and the second rotating disk are movably connected to the two ends of the inner wall of the rotating drum, and a grinding roller is arranged between the first rotating disk and the second rotating disk, and the grinding roller is located at the bottom end of the inner wall of the rotating drum;

[0029] A motor frame is provided on the top of the support frame, a first motor and a fixed frame are provided on the top of the motor frame, a reducer is provided at the output end of the first motor, 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 driving gear, a gear ring is provided on the outside of the rotating cylinder, and the driving gear is meshed with the gear ring.

[0030] In the preferred embodiment, the discharging mechanism includes a fixed sleeve movably connected to the outside of the rotating cylinder, and the fixed sleeve is connected to the support frame through a connecting frame; the connection between the fixed sleeve and the rotating cylinder is in close contact; a discharging pipe is provided at the bottom of the fixed sleeve, and the discharging pipe is connected to the interior of the rotating cylinder; a valve is provided in the discharging pipe.

[0031] In a preferred solution, both ends of the roller are provided with a rotating shaft, which is rotatably connected to the inside of the first rotating disk and the second rotating disk;

[0032] The bottom end of the inner wall of the rotating drum is matched with the roller;

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

[0034] The driving frame also includes a connecting shaft connected to the first turntable, the connecting shaft passes through one end of the rotating cylinder away from the feeding pipe, the connecting shaft is connected to a limiting disk, and the limiting disk is located outside the rotating cylinder; the connecting shaft and the limiting disk are movably connected to the rotating cylinder; the limiting disk is connected to a second motor, the output shaft of the second motor is connected to a driving wheel, the rotating shaft located in the first turntable is provided with a driven wheel, and the driving wheel and the driven wheel are connected by a belt drive; an inner ring is provided on the inner wall of the rotating cylinder, the cross-section of the inner ring is L-shaped, the inner ring is connected to the feeding pipe, the inner ring is located on the inner periphery of the second turntable, and is used to limit the position of the second turntable; an outer ring is provided on the inner wall of the rotating cylinder, and the outer ring is located on the outer periphery of the second turntable, and is used to limit the position of the second turntable.

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

[0036] A first fixed shaft is arranged inside the roller, the first fixed shaft is coaxial with the axis of the roller, a plurality of rotating sleeves are sleeved on the outside of the first fixed shaft, the rotating sleeves rotate around the first fixed shaft, a connecting rod is arranged on the rotating sleeve, a counterweight is arranged at one end of the connecting rod away from the rotating sleeve, a plurality of limit blocks are arranged on the inner wall of the roller, and the limit blocks correspond to the rotating sleeves one by one;

[0037] or

[0038] A second fixed shaft is provided in the roller, the second fixed shaft is coaxial with the axis of the roller, the second fixed shaft is provided with multiple guide sleeves, a sliding rod is slidably connected in the guide sleeve, the sliding rod passes through the guide sleeve, impact blocks are provided at both ends of the sliding rod, and multiple pads are provided on the inner wall of the roller, and the pads correspond to the impact blocks one by one.

[0039] The present invention provides a method and system for removing mica from granite machine-made sand. By adopting the above scheme, the following beneficial effects are achieved:

[0040] 1. First screen into coarse material and fine material, then separate the coarse material by air separation and the fine material by magnetic separation, which can effectively reduce the mica content in all particle sizes of machine-made sand and meet the requirements of mica content ≤ 2% in national and industry standards.

[0041] 2. Only the coarse material is air-selected, which can effectively avoid the disadvantages of poor fine-grained separation effect, large loss of fine-grained machine-made sand and increased sand and gravel fineness modulus after selection. At the same time, the coarse material air-selection process is simple, with less pollution, obvious separation effect, low dust removal pressure and low cost.

[0042] 3. Only fine materials are separated by magnetic separation, which not only has high separation accuracy, but also effectively retains fine-grained stone powder while avoiding the problem of large loss of mica-containing conjoined particles caused by incomplete mica dissociation during coarse-grained magnetic separation, which is beneficial to reducing the loss of machine-made sand.

[0043] 4. Before screening, the mica is kneaded to fully separate the sand and gravel to avoid adhesion, which makes it easier for subsequent screening and ensures the screening effect and the quality of the finished product.

[0044] 5. The coarse and fine materials can be screened during the kneading process, which is more efficient and reduces costs.

[0045] 6. Oscillation is performed during the kneading process, which makes the mica separate more fully, increases the kneading efficiency, and achieves better kneading and separation effects. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0047] Figure 1 It is a flow chart of a method and system for removing mica from granite machine-made sand according to the present invention;

[0048] Figure 2 is a schematic structural diagram of the kneading device of the present invention;

[0049] Figure 3 is a front view of the kneading device of the present invention;

[0050] Figure 4 is a schematic cross-sectional structural diagram of the kneading device of the present invention;

[0051] Figure 5 is a schematic cross-sectional view of an embodiment of the kneading device of the present invention;

[0052] Figure 6 is a schematic structural diagram of the drive frame of the present invention;

[0053] Figure 7 It is a schematic structural diagram of an embodiment of the oscillation frame of the present invention;

[0054] Figure 8 It is a schematic structural diagram of an embodiment of an oscillation frame of the present invention;

[0055] Fig. 9 is a schematic cross-sectional structural diagram of an embodiment of a kneading device of the present invention;

[0056] Fig.10 It is a structural schematic diagram of the connection between the rotating shaft and the first rotating disk of the present invention.

[0057] In the figure:

[0058] Linear vibrating screen 11, air drying bin 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, driving gear 406, gear ring 407, fixed sleeve 501, connecting frame 502, discharge pipe 503, valve 504, driving frame 6, first turntable 601, connecting shaft 602 , limit plate 603, second motor 604, driving wheel 605, driven wheel 606, belt 607, second turntable 608, inner ring 609, outer ring 610, rolling roller 7, rotating shaft 701, oscillation frame 8, first fixed shaft 811, rotating sleeve 812, connecting rod 813, counterweight block 814, limit block 815, second fixed shaft 821, guide sleeve 822, sliding rod 823, impact block 824, pad 825. DETAILED DESCRIPTION

[0060] Embodiment 1:

[0061] Mineral phase analysis shows that the mineral components of a certain granite are mainly plagioclase, quartz, potassium feldspar, amphibole and mica, of which the content of mica accounts for about 8%. The content of each component is shown in Table 1:

[0062] Ore name Plagioclase quartz Potassium feldspar Hornblende Mica Metallic minerals content / % 47 18 16 10 8 1

[0063] Table 1 - Mineral composition of granite

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

[0065] Further screening analysis of the raw material machine-made sand determined that its modulus was 2.63, which belongs to the 2nd zone machine-made sand in the national standard "Construction Sand" GB / T14684. The specific raw material particle size fraction and cumulative sieve residue are shown in Table 2:

[0066]

[0067]

[0068] Table 2 - Raw material sand and gravel particle size and modulus

[0069] In order to effectively remove mica and produce machine-made sand that meets the particle size requirements, such as Figure 1 As shown, the specific implementation includes the following steps:

[0070] S1. Knead the semi-finished machine-made sand obtained by the crushing system, and then screen and grade it to obtain coarse sand and fine sand;

[0071] S2, removing flaky mica from the coarse sand on the sieve obtained in S1 by air separation to obtain heavy products and light products;

[0072] S3, removing the fine mica with weak magnetism from the undersize fine sand obtained in S1 by high gradient wet magnetic separation to obtain a non-magnetic product and a magnetic product;

[0073] S4. Combine the heavy product in S2 with the non-magnetic product in S3 to obtain full-grained machine-made sand with a mica content of <2%.

[0074] Preferably, the sieve opening used for screening and grading in step S1 is 1.18 mm.

[0075] The wind speed of the winnowing in step S2 is 6 m / s.

[0076] The magnetic field strength of the magnetic separation in step S3 is 16000 Oe.

[0077] In step S3, the magnetic product is dried by a drying unit, and the non-magnetic product is dehydrated by a dehydration screen.

[0078] In step S4, the heavy product and the non-magnetic product are mixed by a mixing device to obtain full-grained machine-made sand whose gradation meets the requirements of the specification.

[0079] After sorting, the mica content in the obtained machine-made sand was measured to be 0.67% in accordance with the national standard "Construction Sand" GB / T 14684, the sand and gravel product rate was 54.54%, and the modulus was 2.67, which met the requirements of the particle grading of machine-made sand in Zone 2 in the national standard "Construction Sand" GB / T 14684. The sieve residues of each particle size and the cumulative sieve residues are shown in Table 3:

[0080]

[0081]

[0082] Table 3-Grading and modulus of sand and gravel particles after selection in Example 1

[0083] It can be seen from the above table that after grading and sorting, not only the mica content of the artificial sand is reduced to meet the requirement of ≤2%, but also the overall modulus does not change much compared with the raw materials, and still meets the particle grading requirements of zone 2 artificial sand in the national standard. The raw materials can be used as qualified artificial sand after separate sorting, avoiding the tedious steps of artificial sand preparation.

[0084] Embodiment 2:

[0085] The steps in Example 1 are repeated, except that the magnetic field strength of the magnetic separation in step S3 is 13000 Oe.

[0086] After selection, the mica content of the obtained machine-made sand is 1.48%, the sand and gravel product rate is 65.47%, and the modulus is 2.57, which meets the requirements of the particle grading of machine-made sand in Zone 2 in the national standard "Construction Sand" GB / T 14684. The sieve residues of each particle size and the cumulative sieve residues are shown in Table 4:

[0087]

[0088]

[0089] Table 4 - Grain gradation and modulus of sand and gravel after sorting in Example 2

[0090] Embodiment 3:

[0091] The steps in Example 1 are repeated, except that the wind speed for air separation in step S2 is 4 m / s.

[0092] After selection, the mica content of the obtained machine-made sand is 0.68%, the sand and gravel product rate is 58.97%, and the modulus is 2.78, which meets the requirements of the particle grading of machine-made sand in Zone 2 in the national standard "Construction Sand" GB / T 14684. The sieve residues of each particle size and the cumulative sieve residues are shown in Table 5:

[0093]

[0094] Table 5 - Gradient distribution and modulus of sand and gravel after sorting in Example 3

[0095] Embodiment 4:

[0096] The steps in Example 1 are repeated, except that the wind speed of the air separation in step S2 is 4 m / s, and the magnetic field strength of the magnetic separation in step S3 is 13000 Oe.

[0097] After selection, the mica content of the obtained machine-made sand is 1.42%, the sand and gravel product rate is 69.91%, and the modulus is 2.66, which meets the requirements of the particle grading of machine-made sand in Zone 2 in the national standard "Construction Sand" GB / T 14684. The sieve residues of each particle size and the cumulative sieve residues are shown in Table 6:

[0098]

[0099] Table 6 - Grain gradation and modulus of sand and gravel after sorting in Example 4

[0100] It can be seen from the above embodiments that the mica removal method provided by the present invention can effectively reduce the content of biotite in granite machine-made sand, and can ensure that the gradation of the produced machine-made sand meets the requirements of the specification while satisfying the mica content of ≤2%. The mica removal method provided by the present invention has the advantages of simple process, obvious effect, energy saving and environmental protection, and good production efficiency and economic benefits.

[0101] The technical principle of the present invention is to organically combine the different occurrence characteristics of mica in coarse and fine materials with the respective sorting advantages of gravity and magnetic separation to achieve efficient removal of mica in all particle sizes of sand and gravel. Specifically, the air separation method utilizes the characteristics of mica being crushed and dissociated into flakes in the coarse particle size. Under horizontal wind field conditions, mica has large wind resistance and is easily blown away, thereby achieving separation from heavier sand and gravel; the magnetic separation method utilizes the characteristics of mica having weak magnetism and being fully dissociated in the fine particle size to achieve separation from non-magnetic sand and gravel under high gradient magnetic field conditions, and the semi-finished machine-made sand is rubbed and then screened, which can process the adhered mica-sand and gravel materials, separate the mica from the sand and gravel, and then screen them, ensuring the screening effect.

[0102] Embodiment 5:

[0103] like Figure 1 and 2 As shown, a system for removing mica from granite machine-made sand is characterized by comprising a primary screening mechanism and two secondary screening mechanisms, wherein 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;

[0104] The first-stage screening mechanism includes a kneading device for kneading the semi-finished machine-made sand to facilitate the separation of mica.

[0105] The semi-finished machine-made sand is kneaded and then screened, which can process the adhered mica-sand and gravel, separate the mica from the sand and gravel, and then screen them to ensure the screening effect.

[0106] In the preferred solution, the secondary screening mechanism includes an air separator 13 and a magnetic separator 14, the feed end of the air separator 13 is provided with an air drying bin 12, the discharge end of the magnetic separator 14 is provided with a drying unit 15 and a dewatering screen 16, the drying unit 15 is used to dry the magnetic product, and the dewatering screen 16 is used to process the non-magnetic product, the air drying bin 12, the air separator 13, the magnetic separator 14, the drying unit 15 and the dewatering screen 16 are all existing equipment, and according to the method of the present application, the existing method is then used for control;

[0107] The products selected by the air classifier 13 are mixed with the non-magnetic products through the mixing device 17. The mixing device 17 can be an existing device. According to the method of the present application, the existing method is then used for control.

[0108] Embodiment 6:

[0109] like Figure 2 , 3 As shown in , 6 and 9, the primary screening mechanism also includes a linear vibrating screen 11, and the linear vibrating screen 11 can be an existing device, and the linear vibrating screen 11 is used to screen the product processed by the kneading device;

[0110] The kneading device includes a support frame 2 and a rotating cylinder 3. A plurality of guide rings 201 are provided at the top of the support frame 2. The guide rings 201 are sleeved on the outside of the rotating cylinder 3 through bearings 202. A feed pipe 303 is provided at one end of the rotating cylinder 3. A first discharge hole 301 and a discharge mechanism are provided on the outer peripheral surface of the rotating cylinder 3.

[0111] This embodiment only has one first discharge hole 301, and the aperture of the first discharge hole 301 is larger than the particle diameter of the machine-made sand coarse material. After kneading, the material is discharged through the first discharge hole 301 and the discharge mechanism, and then the kneaded machine-made sand is transported to the linear vibrating screen 11 for screening coarse sand and fine sand.

[0112] A driving frame 6 is provided in the rotating drum 3. The driving frame 6 includes a first rotating disk 601 and a second rotating disk 608. The first rotating disk 601 and the second rotating disk 608 are movably connected to the two ends of the inner wall of the rotating drum 3. A grinding roller 7 is provided between the first rotating disk 601 and the second rotating disk 608. The grinding roller 7 is located at the bottom end of the inner wall of the rotating drum 3. Under the action of the gravity of the grinding roller 7, the first rotating disk 601 and the second rotating disk 608 are driven to rotate relative to the rotating drum 3, so that the grinding roller 7 always moves within the bottom end range of the inner wall of the rotating drum 3, so as to knead the machine-made sand.

[0113] A motor frame 401 is provided on the top of the support frame 2, and a first motor 402 and a fixed frame 404 are provided on the top of the motor frame 401; the first motor 402 can be an existing one, such as a reduction motor, a three-phase motor or a servo motor, etc., and is controlled by existing technology; a reducer 403 is provided at the output end of the first motor 402, and the output shaft of the first motor 402 is connected to the input shaft of the reducer 403, and 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 the gear shaft 405 is connected to a driving gear 406, and a gear ring 407 is provided on the outside of the rotating cylinder 3, and the driving gear 406 is meshed with the gear ring 407.

[0114] When in use, the machine-made sand is fed into the rotating drum 3 through the feed pipe 303 by existing methods (such as dragon conveyor and elevator, etc.), and then the first motor 402 is started to drive the gear shaft 405 to rotate through the reducer 403, thereby driving the driving gear 406 to rotate, which can drive the gear ring 407 to rotate, and finally drive the rotating drum 3 to rotate; during the rotation of the rotating drum 3, the machine-made sand in the rotating drum 3 will be driven to follow the movement, and at the same time, the machine-made sand is continuously rolled and kneaded by the roller 7, so that the mica and sand and gravel adhered in the machine-made sand can be separated for subsequent screening;

[0115] Since the roller 7 always moves within the bottom end range of the inner wall of the rotating drum 3, the roller 7 and the rotating drum 3 move relative to each other when the rotating drum 3 rotates, so as to complete the kneading of the machine-made sand;

[0116] After 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.

[0117] Embodiment 7:

[0118] like Figure 2 , 3 As shown in , 4, 5 and 6, the kneading device includes a support frame 2 and a rotating cylinder 3, a plurality of guide rings 201 are provided at the top of the support frame 2, the guide rings 201 are sleeved on the outside of the rotating cylinder 3 through bearings 202, and a feed pipe 303 is provided at one end of the rotating cylinder 3; a first discharge hole 301 and a second discharge hole 302 are provided on the outer periphery of the rotating cylinder 3, and two discharge mechanisms are provided on the outer periphery of the rotating cylinder 3; the two discharge mechanisms are respectively connected to the first discharge hole 301 and the second discharge hole 302;

[0119] This embodiment no longer uses the linear vibrating screen 11. Instead, after kneading is completed, 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 vibrating screen separately, which saves costs.

[0120] A driving frame 6 is provided in the rotating drum 3. The driving frame 6 includes a first rotating disk 601 and a second rotating disk 608. The first rotating disk 601 and the second rotating disk 608 are movably connected to the two ends of the inner wall of the rotating drum 3. A grinding roller 7 is provided between the first rotating disk 601 and the second rotating disk 608. The grinding roller 7 is located at the bottom end of the inner wall of the rotating drum 3. Under the action of the gravity of the grinding roller 7, the first rotating disk 601 and the second rotating disk 608 are driven to rotate relative to the rotating drum 3, so that the grinding roller 7 always moves within the bottom end range of the inner wall of the rotating drum 3, so as to knead the machine-made sand.

[0121] A motor frame 401 is provided on the top of the support frame 2, a first motor 402 and a fixed frame 404 are provided on the top of the motor frame 401, a reducer 403 is provided at the output end of the first motor 402, 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 driving gear 406, a gear ring 407 is provided on the outside of the rotating cylinder 3, and the driving gear 406 is meshed with the gear ring 407.

[0122] When in use, the machine-made sand is fed into the rotating drum 3 through the feed pipe 303 by existing methods (such as dragon conveyor and elevator, etc.), and then the first motor 402 is started to drive the gear shaft 405 to rotate through the reducer 403, thereby driving the driving gear 406 to rotate, which can drive the gear ring 407 to rotate, and finally drive the rotating drum 3 to rotate; during the rotation of the rotating drum 3, the machine-made sand in the rotating drum 3 will be driven to follow the movement, and at the same time, the machine-made sand is continuously rolled and kneaded by the roller 7, so that the mica and sand and gravel adhered in the machine-made sand can be separated for subsequent screening;

[0123] Since the roller 7 always moves within the bottom end range of the inner wall of the rotating drum 3, the roller 7 and the rotating drum 3 move relative to each other when the rotating drum 3 rotates, so as to complete the kneading of the machine-made sand;

[0124] 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, and then the next step can be carried out. The operation is simple, and screening is completed while kneading, which increases efficiency and reduces cost.

[0125] In the above embodiments, as shown in 2, 4, 5 and 9, the discharge mechanism includes a fixed sleeve 501 movably sleeved on the outside of the rotating cylinder 3, and 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; a discharge pipe 503 is provided at the bottom of the fixed sleeve 501, and the discharge pipe 503 is connected to the inside of the rotating cylinder 3; a valve 504 is provided in the discharge pipe 503, and the valve 504 is preferably an existing gate valve;

[0126] During kneading, the valve 504 is closed, and the machine-made sand is kneaded in the rotating cylinder 3. The machine-made sand that enters the first discharge hole 301 and the second discharge hole 302 will naturally fall down under the action of gravity when the rotating cylinder 3 rotates to the upper side, and will not affect the overall kneading effect. When discharge is needed, the valve 504 corresponding to the second discharge hole 302 can be opened to discharge fine sand. After the discharge of the fine sand is completed, the valve 504 corresponding to the first discharge hole 301 can be opened to discharge coarse sand. The operation is simple and convenient for discharge.

[0127] The size of the first discharge hole 301 ensures that the coarse material can pass through smoothly, and the size of the second discharge hole 302 is determined according to actual needs. For example, if the diameter limit defined by the diameter of fine sand and coarse sand is 1 mm, the aperture of the second discharge hole 302 is 1 mm.

[0128] Embodiment 8:

[0129] like Figure 4 , 5 As shown in FIG. 6 , both ends of the roller 7 are provided with a rotating shaft 701 , and the rotating shaft 701 is rotatably connected to the inside of the first rotating disk 601 and the second rotating disk 608 ;

[0130] The bottom end of the inner wall of the rotating drum 3 is matched with the roller 7; Figure 4 As shown, the roller 7 may be cylindrical; Figure 5 As shown, the middle part of the roller 7 is cylindrical, and the two ends are truncated cone-shaped. The inner wall of the rotating cylinder 3 is adapted to the roller 7, so that the machine-made sand in the rotating cylinder 3 is gathered toward the middle, which is convenient for discharging.

[0131] The inner wall of the rotating cylinder 3 and the surface of the roller 7 are both provided with protrusions to increase the kneading effect;

[0132] The driving frame 6 also includes a connecting shaft 602 connected to the first rotating disk 601, the connecting shaft 602 passes through the end of the rotating cylinder 3 away from the feeding tube 303, the connecting shaft 602 is connected to the limiting disk 603, and the limiting disk 603 is located outside the rotating cylinder 3; the connecting shaft 602 and the limiting disk 603 are movably connected to the rotating cylinder 3; the limiting disk 603 is connected to the second motor 604, and the second motor 604 is preferably an existing motor, such as a servo motor or a stepping motor. The output shaft of the second motor 604 is connected to a driving wheel 605, and the rotating shaft 701 located in the first rotating disk 601 is provided with a driven wheel. The driving wheel 605 and the driven wheel 606 are connected by a belt 607, and the belt 607 is preferably an elastic belt. Transmission teeth are provided between the belt 607 and the driving wheel 605 and the driven wheel 606; 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 feeding pipe 303, the inner ring 609 is located at the inner periphery 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, and the outer ring 610 is located at the outer periphery of the second turntable 608, and is used to limit the position of the second turntable 608.

[0133] During kneading, the second motor 604 is started to drive the driving wheel 605 to rotate, thereby driving the driven wheel 606 to rotate through the belt 607, which can drive the rotating shaft 701 and the grinding roller 7 to rotate, so that the grinding roller 7 rotates relative to the rotating drum 3, thereby increasing the kneading effect and ensuring the kneading quality. The grinding roller 7 preferably rotates in the opposite direction to the rotating drum 3.

[0134] As needed, the belt transmission can also be replaced with gear transmission in this application, depending on the actual situation.

[0135] Embodiment 9:

[0136] like Figure 7 As shown, the roller 7 is hollow inside, and an oscillation frame 8 is provided inside the roller 7. The oscillation frame 8 includes:

[0137] A first fixed shaft 811 is provided inside the roller 7, and the first fixed shaft 811 is coaxial with the axis of the roller 7. A plurality of rotating sleeves 812 are sleeved on the outside of the first fixed shaft 811. An existing bearing is provided between the rotating sleeve 812 and the first fixed shaft 811. The rotating sleeve 812 rotates around the first fixed shaft 811. The rotating sleeve 812 is provided with a connecting rod 813. A counterweight block 814 is provided at one end of the connecting rod 813 away from the rotating sleeve 812. A plurality of limit blocks 815 are provided on the inner wall of the roller 7, and the limit blocks 815 correspond to the rotating sleeve 812 one by one.

[0138] During the rotation of the grinding roller 7, the first fixed shaft 811 and the limit block 815 will be driven to rotate. When the limit block 815 rotates to the bottom of the first fixed shaft 811, it will push the counterweight block 814 to make it rotate accordingly. When the counterweight block 814 is pushed to the upper limit position, the counterweight block 814 will move down rapidly under the action of gravity after passing the upper limit position. At this time, the counterweight block 814 drives the connecting rod 813 and the rotating sleeve 812 to rotate to the lower limit position around the first fixed shaft 811, and will swing under the action of potential energy. In this process, the potential energy will act on the first fixed shaft 811, and then act on the grinding roller 7 through the first fixed shaft 811, so that the grinding roller 7 will oscillate, thereby enhancing the kneading effect on the machine-made sand.

[0139] Embodiment 10:

[0140] like Figure 8 As shown, the roller 7 is hollow inside, and an oscillation frame 8 is provided inside the roller 7. The oscillation frame 8 includes:

[0141] A second fixed shaft 821 is provided inside the roller 7, and the second fixed shaft 821 is coaxial with the axis of the roller 7. The second fixed shaft 821 is provided with a plurality of 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. A plurality of pads 825 are provided on the inner wall of the roller 7, and the pads 825 correspond to the impact blocks 824 one by one.

[0142] During the rotation of the roller 7, the second fixed shaft 821, the guide sleeve 822 and the pad 825 are driven to rotate, thereby driving the sliding rod 823 and the impact block 824 to rotate. When the sliding rod 823 rotates to a 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 machine-made sand.

[0143] In a further embodiment, Fig.10 As shown, in order to ensure the normal oscillation in Example 9 and Example 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. Therefore, while ensuring normal rotation, the elastic rubber sleeve will be compressed when the roller 7 oscillates, so that the oscillation of the roller 7 will not be restricted by the first turntable 601 or the second turntable 608, thereby ensuring the normal oscillation.

[0144] The mica referred to in the present invention includes but is not limited to biotite, and the screened artificial sand includes but is not limited to granite artificial sand. Granite artificial sand cannot be interpreted as a limitation to the present application.

[0145] The above embodiments are only preferred technical solutions of the present invention and should not be regarded as limiting the present invention. The protection scope of the present invention shall be the technical solutions recorded in the claims, including equivalent replacement solutions of the technical features in the technical solutions recorded in the claims. That is, equivalent replacement improvements within this scope are also within the protection scope of the present invention.

Claims

1. A method for removing mica from granite machine-made sand, characterized by: The following steps are involved: S1. Knead the semi-finished machine-made sand, and screen and grade it to obtain coarse sand and fine sand; S2, removing flaky mica from the coarse sand by air separation to obtain heavy products and light products; S3, removing the fine mica with weak magnetism from the fine sand by high gradient wet magnetic separation to obtain non-magnetic products and magnetic products; S4. The heavy product is combined with the non-magnetic product to obtain full-grained machine-made sand with a mica content of <2%.

2. The method for removing mica from granite machine-made sand according to claim 1 is characterized in that: In step S2, the coarse sand obtained by screening is air-dried and then air-selected at a wind speed of 2 to 10 m / s.

3. The method for removing mica from granite machine-made sand according to claim 1 is characterized in that: The magnetic field strength of the magnetic separation in step S3 is 10000 to 20000 Oe; In step S3, the non-magnetic product after magnetic separation is dehydrated through a dehydration screen, and the magnetic product is dried through a drying unit.

4. A system for removing mica from granite machine-made sand, characterized by: 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 first-stage screening mechanism includes a kneading device for kneading the semi-finished machine-made sand to facilitate the separation of mica.

5. The system for removing mica from granite machine-made sand according to claim 4 is characterized by: The secondary screening mechanism comprises an air separator (13) and a magnetic separator (14); the feed end of the air separator (13) is provided with an air drying bin (12); the discharge end of the magnetic separator (14) is provided with a drying unit (15) and a dewatering screen (16); the drying unit (15) is used to dry the magnetic product, and the dewatering screen (16) is used to process the non-magnetic product; The product selected by the air separator (13) is mixed with the non-magnetic product through a mixing device (17).

6. The system for removing mica from granite machine-made sand according to claim 5 is characterized by: The first-stage screening mechanism further comprises a linear vibrating screen (11), and the linear vibrating screen (11) is used to screen the product processed by the kneading device; The kneading device comprises a support frame (2) and a rotating cylinder (3); a plurality of guide rings (201) are provided at the top of the support frame (2); the guide rings (201) are sleeved on the outside of the rotating cylinder (3) through bearings (202); a feed pipe (303) is provided at one end of the rotating cylinder (3); and a first discharge hole (301) and a discharge mechanism are provided on the outer peripheral surface of the rotating cylinder (3); A driving frame (6) is provided inside the rotating cylinder (3), and the driving frame (6) comprises a first rotating disk (601) and a second rotating disk (608), and the first rotating disk (601) and the second rotating disk (608) are movably connected to two ends of the inner wall of the rotating cylinder (3), and a grinding roller (7) is provided between the first rotating disk (601) and the second rotating disk (608), and the grinding roller (7) is located at the bottom end of the inner wall of the rotating cylinder (3); A motor frame (401) is provided on the top of the support frame (2), a first motor (402) and a fixing frame (404) are provided on the top of the motor frame (401), a reducer (403) is provided at the output end of the first motor (402), an output shaft of the first motor (402) is connected to an 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 fixing frame (404), the gear shaft (405) is connected to a driving gear (406), a gear ring (407) is provided on the outside of the rotating cylinder (3), and the driving gear (406) is meshed with the gear ring (407).

7. The system for removing mica from granite machine-made sand according to claim 5 is characterized by: The kneading device comprises a support frame (2) and a rotating cylinder (3); a plurality of guide rings (201) are provided at the top of the support frame (2); the guide rings (201) are sleeved on the outside of the rotating cylinder (3) through bearings (202); a feed pipe (303) is provided at one end of the rotating cylinder (3); a first discharge hole (301) and a second discharge hole (302) are provided on the outer periphery of the rotating cylinder (3); two discharge mechanisms are provided on the outer periphery of the rotating cylinder (3); the two discharge mechanisms are respectively connected to the first discharge hole (301) and the second discharge hole (302); A driving frame (6) is provided inside the rotating cylinder (3), and the driving frame (6) comprises a first rotating disk (601) and a second rotating disk (608), and the first rotating disk (601) and the second rotating disk (608) are movably connected to two ends of the inner wall of the rotating cylinder (3), and a grinding roller (7) is provided between the first rotating disk (601) and the second rotating disk (608), and the grinding roller (7) is located at the bottom end of the inner wall of the rotating cylinder (3); A motor frame (401) is provided on the top of the support frame (2), a first motor (402) and a fixing frame (404) are provided on the top of the motor frame (401), a reducer (403) is provided at the output end of the first motor (402), an output shaft of the first motor (402) is connected to an 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 fixing frame (404), the gear shaft (405) is connected to a driving gear (406), a gear ring (407) is provided on the outside of the rotating cylinder (3), and the driving gear (406) is meshed with the gear ring (407).

8. A system for removing mica from granite machine-made sand according to any one of claims 6 or 7, characterized in that: The discharge mechanism comprises a fixed sleeve (501) movably sleeved on the outside of the rotating cylinder (3), the fixed sleeve (501) being connected to the support frame (2) via a connecting frame (502); the connection between the fixed sleeve (501) and the rotating cylinder (3) being in close contact; a discharge pipe (503) is provided at the bottom of the fixed sleeve (501), the discharge pipe (503) being in communication with the interior of the rotating cylinder (3); and a valve (504) is provided inside the discharge pipe (503).

9. A system for removing mica from granite machine-made sand according to any one of claims 6 or 7, characterized in that: Both ends of the roller (7) are provided with a rotating shaft (701), and the rotating shaft (701) is rotatably connected to the inside of the first rotating disk (601) and the second rotating disk (608); The bottom end of the inner wall of the rotating cylinder (3) is matched with the roller (7); The inner wall of the rotating cylinder (3) and the surface of the roller (7) are both provided with protrusions; The driving frame (6) further comprises a connecting shaft (602) connected to the first rotating disk (601), the connecting shaft (602) passing through an end of the rotating cylinder (3) away from the feeding pipe (303), the connecting shaft (602) being connected to a limiting disk (603), and the limiting disk (603) being located outside the rotating cylinder (3); the connecting shaft (602) and the limiting disk (603) are both movably connected to the rotating cylinder (3); The limiting disk (603) is connected to a second motor (604), the output shaft of the second motor (604) is connected to a driving wheel (605), a rotating shaft (701) located in the first rotating disk (601) is provided with a driven wheel (606), and the driving wheel (605) and the driven wheel (606) are connected by a belt (607); an inner ring (609) is provided on the inner wall of the rotating cylinder (3), the cross section of the inner ring (609) is L-shaped, the inner ring (609) is connected to the feeding pipe (303), the inner ring (609) is located on the inner periphery of the second rotating disk (608), and is used to limit the position of the second rotating disk (608); an outer ring (610) is provided on the inner wall of the rotating cylinder (3), and the outer ring (610) is located on the outer periphery of the second rotating disk (608), and is used to limit the position of the second rotating disk (608).

10. A system for removing mica from granite machine-made sand according to any one of claims 6 or 7, characterized in that: The roller (7) is hollow inside, and an oscillating frame (8) is arranged inside the roller (7). The oscillating frame (8) comprises: A first fixed shaft (811) is provided inside the roller (7), the first fixed shaft (811) is coaxial with the axis of the roller (7), a plurality of 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), a connecting rod (813) is provided on the rotating sleeve (812), a counterweight (814) is provided at one end of the connecting rod (813) away from the rotating sleeve (812), and a plurality of limit blocks (815) are provided on the inner wall of the roller (7), the limit blocks (815) correspond one to one with the rotating sleeves (812); or A second fixed shaft (821) is provided inside the roller (7), the second fixed shaft (821) is coaxial with the axis of the roller (7), the second fixed shaft (821) is provided with a plurality of 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), and a plurality of pads (825) are provided on the inner wall of the roller (7), and the pads (825) correspond to the impact blocks (824) one by one.

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