A sand grinding system with recycled grinding media

Abstract

The present invention relates to the technical field of sand mills, and particularly to a sand grinding system with recycled grinding media, which includes a grinding cylinder, a stirring mechanism, a grinding media adding device, and a screening mechanism. During use, the grinding media and the pulp enter the grinding channel of the grinding cylinder according to a preset ratio. The pulp is ground under the action of the grinding media, and the grinding media flows backward under the thrust of the pulp. The ground pulp and the grinding media are discharged together from the pulp outlet of the grinding cylinder. At the screening mechanism outside the grinding cylinder, the grinding media is separated from the ground pulp, and the grinding media is returned for recycling. The ratio of the grinding media to the pulp can be adjusted, and the grinding media can follow the pulp to be discharged. The density of the grinding media before and after the grinding cylinder is consistent, improving the grinding efficiency. Since the influence of the pulp pressure on the distribution density of the grinding media is eliminated, it is applicable to pulps with high concentrations, has a high probability of contacting the grinding media, and greatly improves the grinding efficiency. The screening mechanism is located outside the grinding cylinder, which can reduce the wear of the grinding media on it, has a low probability of failure, and avoids the trouble caused by frequent shutdowns for maintenance.

Description

Technical Field

[0001] The present invention relates to the technical field of sand mills, and particularly to a sand grinding system with recycled grinding media. Background Art

[0002] Sand mills are currently the most versatile, advanced, and efficient grinding equipment for materials. Generally, they can be classified into horizontal sand mills, basket sand mills, vertical sand mills, etc. according to their performance. The grinding chamber of a sand mill is relatively narrow, the gap between the stirring rods is small, and the grinding energy is relatively concentrated. With a high-performance cooling system and an automatic control system, continuous processing and discharging of materials can be achieved, greatly improving production efficiency. In particular, due to the maturity of the design and manufacturing technology of large horizontal sand mills in recent years, it has become a reality to apply them to the ultrafine grinding of mineral powder.

[0003] The basic principle of a sand mill is as follows: In a closed grinding cylinder, media for grinding (abbreviated as grinding beads or grinding media), such as zirconium beads (zirconium dioxide), glass beads, etc., are installed. The media in the grinding cylinder are stirred by a turntable or rod pins installed on the rotating shaft, causing the media to move relative to each other. The slurry to be ground passes through the gaps between the grinding media and is ground to achieve a pulverizing effect. After grinding, the slurry flows out from the slurry outlet of the grinding cylinder, and the media remain in the grinding cylinder. Theoretically, the higher the relative speed of the grinding media, the greater the collision force and the better the grinding fineness. However, in practice, due to various factors, the flow rate of the slurry and the speed of the grinding media cannot be too high.

[0004] The existing sand mills have the following defects:

[0005] First, the slurry to be ground flows into the grinding cylinder from the feed inlet at one end, exerting a lateral thrust on the grinding media in the grinding cylinder, which will push the grinding media towards the slurry outlet. As a result, the density of the grinding media in the front section (near the feed inlet) of the grinding cylinder is small, while the density of the grinding media in the rear section (near the slurry outlet) is large, that is, the density of the grinding media in the grinding cylinder is uneven and uncontrollable. This leads to low grinding efficiency in the front section of the grinding cylinder, and the excessive density in the rear section of the grinding cylinder will cause difficulties in the flow of the slurry, which also affects the overall grinding efficiency and increases energy consumption.

[0006] Second, regarding the concentration of the slurry, theoretically, the greater the concentration of the slurry, the higher the content of solid particles and the higher the grinding efficiency. However, in practice, the greater the concentration of the slurry, the greater the thrust on the grinding media in the grinding cylinder, and the more obvious the above first defect. Therefore, in actual production, the concentration of the slurry cannot be too high, and for some slurries, it even needs to be diluted before grinding, which greatly reduces the grinding efficiency.

[0007] Thirdly, in order to prevent the grinding media from flowing out, an existing sand mill is provided with a filter screen at the rear end of the grinding cylinder, and a centrifugal rotor is arranged at the filter screen to separate the ground pulp from the grinding media after grinding. However, the filter screen is easily damaged by the extrusion of the grinding media, resulting in frequent shutdowns of the sand mill for maintenance. Moreover, the filter screen is located inside the grinding cylinder, making maintenance rather troublesome and reducing production efficiency. Summary of the Invention

[0008] In view of the above technical problems existing in the prior art, the present invention provides a sand grinding system with recycled grinding media.

[0009] To achieve the above object, the present invention provides the following technical solutions:

[0010] Provided is a sand grinding system with recycled grinding media, including a grinding cylinder and a stirring mechanism. The grinding cylinder is provided with a slurry inlet and a slurry outlet, and a grinding channel communicating the slurry inlet and the slurry outlet is arranged inside the grinding cylinder. The stirring mechanism agitates the grinding media in the grinding channel. It is characterized in that: the sand grinding system further includes a grinding media adding device and a screening mechanism. The screening mechanism is located outside the grinding cylinder. The grinding media adding device adds the grinding media into the grinding channel from the front end of the grinding cylinder. Under the action of the slurry flowing in from the slurry inlet, the grinding media is discharged from the slurry outlet of the grinding cylinder to the screening mechanism, so as to separate the ground pulp from the grinding media.

[0011] Specifically, the sand grinding system further includes a raw slurry tank, a main slurry pump and a main slurry pipe. The main slurry pump is respectively connected to the raw slurry tank and the slurry inlet through the main slurry pipe;

[0012] The sand grinding system further includes a finished slurry tank and a discharge pipe. The slurry outlet is connected to the finished slurry tank through the discharge pipe. The finished slurry tank is located below the screening mechanism to receive the slurry after filtering and separating the grinding media.

[0013] Specifically, the grinding media adding device includes a grinding media hopper, a pressure medium slurry pipe, a valve housing, a valve core, a surplus slurry discharge pipe and a medium inlet pipe. The medium inlet pipe is connected to the front end of the grinding channel. The valve core is movably installed in the valve housing, and the valve core is provided with more than three channels. The valve housing moves so that different channels are sequentially connected to the grinding media hopper, connected to the pressure medium slurry pipe and the medium inlet pipe, and connected to the surplus slurry discharge pipe; The raw slurry tank is provided with a pressure medium pump, and the pressure medium pump is respectively connected to the pressure medium slurry pipe and the raw slurry tank.

[0014] Specifically, the grinding media adding device further includes a grinding media lifting mechanism, which includes a feeding hopper, a material lifting screw barrel and a discharge pipe. The feeding hopper is located at the screening mechanism to receive the screened grinding media; The material lifting screw barrel includes a medium conveying pipe, a screw feeding rod arranged in the medium conveying pipe and a feeding motor for driving the screw feeding rod to rotate. The discharge pipe is connected to the upper end of the medium conveying pipe and the grinding media hopper.

[0015] Specifically, the stirring mechanism includes an inner rotating cylinder, a main shaft coaxially fixed with the inner rotating cylinder and a main motor for driving the main shaft to rotate. The inner rotating cylinder is arranged inside the grinding cylinder, and a grinding channel is formed between the outer wall of the inner rotating cylinder and the inner wall of the grinding cylinder;

[0016] The outer wall of the inner rotating cylinder is provided with a plurality of moving pin columns distributed axially, and the inner wall of the grinding cylinder is provided with a plurality of static pin columns distributed axially. The static pin columns and the moving pin columns are arranged staggeredly in the circumferential direction in the grinding channel; the slurry inlet is located at the front end of the grinding cylinder, and the front end face of the inner rotating cylinder is provided with a front slurry homogenizing fan.

[0017] Specifically, the grinding cylinder is provided with an external heat dissipation structure, which includes a water jacket covering the outside of the grinding cylinder. An external cooling channel is formed between the water jacket and the grinding cylinder. The external cooling channel is provided with an external cooling water inlet pipe and an external cooling drain pipe;

[0018] The stirring mechanism is provided with an internal heat dissipation structure, which includes an inner sleeve arranged inside the main shaft. An internal cooling water inlet channel is opened inside the inner sleeve. A water guide cap is provided at the rear end of the inner sleeve. The water guide cap is provided with a radially extending channel communicating with the internal cooling water inlet channel;

[0019] An internal cooling water outlet channel is provided between the inner sleeve and the main shaft. One end of the internal cooling water outlet channel communicates with the inner front end part of the inner rotating cylinder. The other end of the internal cooling water outlet channel penetrates outside the grinding cylinder and is connected with an internal cooling drain wheel. The internal cooling drain wheel is fixed to the main shaft, and a water collecting cover is surrounded by its outer periphery. The water collecting cover is provided with an internal cooling drain pipe.

[0020] Specifically, an ultrasonic transmitter is provided at the inner end part of the grinding cylinder. The ultrasonic transmitter is aligned with the grinding channel. The slurry outlet is located at a position close to the rear end of the side wall of the grinding cylinder.

[0021] Specifically, the moving pin columns and / or the static pin columns close to the ultrasonic transmitter are arranged obliquely away from the ultrasonic transmitter.

[0022] Specifically, a guarding mechanism is provided at the rear end part of the grinding cylinder, which includes a guarding pipe and a rear slurry homogenizing fan. The guarding pipe communicates with the rear end part of the grinding cylinder. The rear slurry homogenizing fan is fixed to the outer side part of the rear end of the inner rotating cylinder.

[0023] Specifically, the screening mechanism includes a vibrating filter disc, an elastic support seat and a vibration driving member. The vibrating filter disc is fixed on the elastic support seat, and the vibration driving member drives the vibrating filter disc to vibrate.

[0024] The beneficial effects of the present invention:

[0025] In the sand grinding system with recycled grinding media of the present invention, when in use, the grinding media and the pulp enter the grinding channel of the grinding cylinder according to a preset ratio. The pulp is ground under the action of the grinding media, and the grinding media flows backward under the thrust of the pulp. The ground pulp and the grinding media are discharged together from the slurry outlet of the grinding cylinder. The grinding media is separated from the ground pulp at the screening mechanism outside the grinding cylinder, and the grinding media returns for recycling. Compared with the prior art, it has the following advantages:

[0026] First, the ratio of the grinding medium to the pulp can be adjusted, and the grinding medium can be discharged from the pulp outlet of the grinding cylinder following the pulp. Therefore, the density of the grinding medium inside the grinding cylinder can be made basically consistent from front to back, which can improve the grinding efficiency.

[0027] Second, since the influence of the pulp pressure on the distribution density of the grinding medium is excluded, it can be applied to pulp with a relatively high concentration. Such pulp has many solid particles and a high probability of contacting the grinding medium, greatly improving the grinding efficiency of the high-concentration pulp.

[0028] Third, since the screening mechanism is located outside the grinding cylinder, the extrusion wear caused by the grinding medium can be reduced, and the probability of failure is low. Furthermore, the trouble caused by frequent shutdowns for maintenance can be avoided. Description of the Drawings

[0029] Figure 1 It is a schematic diagram of the principle of the sand grinding system with circulating use of the grinding medium in the embodiment.

[0030] Figure 2 It is a partial schematic diagram of the principle of the sand grinding system with circulating use of the grinding medium in the embodiment.

[0031] Figure 3 For Figure 2 the schematic diagram of the inclined arrangement of the leftmost moving pin shaft of the grinding cylinder in

[0032] Figure 4 It is a schematic diagram of the principle of the grinding medium adding device in the embodiment.

[0033] Figure 5 It is a schematic diagram of the principle of the cooperation between the valve core and the rotating shaft of the grinding medium adding device in the embodiment.

[0034] Figure 6 It is a schematic diagram of the use state of the grinding medium adding device in the embodiment.

[0035] Reference Signs:

[0036] Grinding cylinder 1, slurry inlet 11, grinding channel 12, static pin column 13;

[0037] Stirring mechanism 2, inner rotating cylinder 21, main shaft 22, main motor 23, front slurry homogenizing fan 24, moving pin column 25;

[0038] Raw pulp cylinder 31, main slurry pump 32, main slurry pipe 33, pressure medium pump 34;

[0039] Screening mechanism 4, vibrating filter disk 41, elastic support seat 42;

[0040] Finished pulp cylinder 51, discharge pipe 52;

[0041] Media adding device 6, media hopper 61, media pressing slurry pipe 62, valve housing 63, housing body 631, upper end cover 632, lower end cover 633, valve core 64, media inlet pipe 65, residual slurry discharge pipe 66, rotating shaft 67, stepper motor 68; Media lifting mechanism 69, feed hopper 691, material lifting spiral cylinder 692, media conveying pipe 693, spiral feeding rod 694, feeding motor 695, discharge pipe 696;

[0042] External heat dissipation structure 7, water jacket 71, external cooling channel 72, external cooling water inlet pipe 73, external cooling water discharge pipe 74;

[0043] Internal heat dissipation structure 8, inner sleeve 81, water guiding cap 82, radially extending channel 83, internal cooling water outlet channel 84, internal cooling water drainage wheel 85, water collecting cover 86, internal cooling water discharge pipe 87;

[0044] Ultrasonic transmitter 9;

[0045] Media retaining mechanism 10, media retaining pump 101, media retaining pipe 102, rear slurry equalizing fan 103. Specific embodiments

[0046] The present invention will be described in detail below in conjunction with specific embodiments and the accompanying drawings.

[0047] The sand grinding system for recycling media in this embodiment, as Figures 1 to 6 shown, includes a grinding cylinder 1 and a stirring mechanism 2. The front end of the grinding cylinder 1 is provided with a slurry inlet 11, and the rear end is provided with a slurry outlet. A grinding channel 12 connecting the slurry inlet 11 and the slurry outlet is arranged inside the grinding cylinder 1, and the stirring mechanism 2 agitates the media in the grinding channel 12. The stirring mechanism 2 includes an inner rotating cylinder 21, a main shaft 22 coaxially fixed with the inner rotating cylinder 21, and a main motor 23 for driving the main shaft 22 to rotate. The inner rotating cylinder 21 is coaxially arranged inside the grinding cylinder 1, and the annular space between the outer wall of the inner rotating cylinder 21 and the inner wall of the grinding cylinder 1 serves as the grinding channel 12. The front end face of the inner rotating cylinder 21 is provided with a front slurry equalizing fan 24, which rotates together with the inner rotating cylinder 21, and its function is to evenly guide the slurry entering from the slurry inlet 11 radially to the grinding channel 12. A plurality of moving pin columns 25 are arranged on the outer wall of the inner rotating cylinder 21 along the axial direction, and a plurality of static pin columns 13 are arranged on the inner wall of the grinding cylinder 1 along the axial direction. The static pin columns 13 and the moving pin columns 25 are arranged staggeredly in the circumferential direction in the grinding channel 12.

[0048] The sand grinding system further includes a raw pulp tank 31, a main pulp pump 32, and a main pulp pipe 33. The main pulp pump 32 is respectively connected to the raw pulp tank 31 and the pulp inlet 11 through the main pulp pipe 33, and is used to inject the pulp to be ground into the grinding channel 12 under high pressure. The sand grinding system further includes a screening mechanism 4, a formed pulp tank 51, and a discharge pipe 52. The screening mechanism 4 is located outside the grinding cylinder 1. Under the action of the pulp flowing in from the pulp inlet 11, the grinding medium is discharged from the pulp outlet of the grinding cylinder 1 to the screening mechanism 4, so that the ground pulp is separated from the grinding medium. The pulp outlet is connected to the formed pulp tank 51 through the discharge pipe 52. The formed pulp tank 51 is located below the screening mechanism 4 to receive the pulp after the grinding medium is filtered and separated. The screening mechanism 4 includes a vibrating filter plate 41, an elastic support seat 42, and a vibration driving member (such as a vibration motor). The vibrating filter plate 41 is fixed on the elastic support seat 42, and the vibration driving member drives the vibrating filter plate 41 to vibrate.

[0049] How to jointly put the grinding medium and the pulp into the grinding cylinder 1 is one of the key problems in realizing the present invention. If the grinding medium is directly placed in the pulp and transported by the pulp pump, since the pulp transported by the pulp pump has a large pressure, it will cause wear of the pipeline and the main pulp pump 32. In addition, the grinding medium will face the problem of positive pressure when entering the grinding cylinder 1. Since the stirring mechanism 2 generates a large positive pressure in the grinding cylinder 1 during operation, if the grinding medium is directly put into the grinding cylinder 1, the grinding medium will be forced outwards due to the pressure and it will be impossible to put the grinding medium into the grinding cylinder 1. Therefore, the innovation of the present invention for this problem lies in setting up a grinding medium adding device 6:

[0050] Its structure includes a grinding medium hopper 61, a pressure medium pulp pipe 62, a valve housing 63, a valve core 64, a medium inlet pipe 65, and a surplus pulp discharge pipe 66. The grinding medium hopper 61 is in the shape of a funnel with an upwardly opening that gradually increases. The medium inlet pipe 65 is connected to the grinding channel 12 and is arranged obliquely with respect to the plumb line. A rotating shaft 67 passes through the center of the valve core 64, and the valve core 64 is rotatably installed in the valve housing 63. The valve housing 63 is provided with a stepping motor 68, and the output shaft of the stepping motor 68 is fixed to the rotating shaft 67 to drive the rotating shaft 67 to rotate step by step. The valve core 64 is provided with more than three channels, and the more than three channels of the valve core 64 are distributed around the rotating shaft 67. The raw pulp tank 31 is provided with a pressure medium pump 34, and the pressure medium pump 34 is respectively connected to the pressure medium pulp pipe 62 and the raw pulp tank 31.

[0051] Process of adding grinding media: During operation, the stepping motor 68 drives the valve core 64 to rotate step by step, causing each channel to move three positions in sequence: ① Feeding position: Connecting the grinding media hopper 61 so that the grinding media in the grinding media hopper 61 falls into the channel due to gravity; ② Discharging position: Connecting the pressure medium slurry pipe 62 and the inlet medium pipe 65 simultaneously to high-pressure transport the slurry in the raw slurry cylinder 31 through the pressure medium slurry pipe 62 under the action of the pressure medium pump 34, and discharging the grinding media in the channel into the grinding channel 12 from the inlet medium pipe 65 under hydraulic action; ③ Emptying position: Connecting the surplus slurry discharge pipe 66 to empty the liquid in the channel. The above three positions are cyclically switched, thus realizing the continuous and smooth addition of grinding media into the grinding cylinder 1. Among them, the pressure of the pressure medium slurry pipe 62 is greater than the pressure of the slurry flowing into the grinding channel 12 from the slurry inlet 11, so that the grinding media can overcome the positive pressure in the grinding channel 12 and enter smoothly. In practice, the number of channels of the valve core 64 can be set to other numbers more than three.

[0052] Specifically, the valve housing 63 includes a cylindrical housing body 631, and an upper end cover 632 and a lower end cover 633 respectively located at both ends of the housing body 631. The valve core 64 is cylindrical, and the outer wall of the valve core 64 is in clearance fit with the inner wall of the housing body 631, and there is clearance fit between the end face of the valve core 64 and the upper end cover 632 and the lower end cover 633. The grinding media hopper 61 and the pressure medium slurry pipe 62 are fixed to the upper end cover 632, and the inlet medium pipe 65 and the surplus slurry discharge pipe 66 are fixed to the lower end cover 633.

[0053] In this embodiment, the grinding media adding device 6 further includes a grinding media lifting mechanism 69, which includes a feeding hopper 691, a material lifting spiral cylinder 692 and a discharge pipe 696. The feeding hopper 691 is located at the screening mechanism 4 to receive the screened grinding media; the material lifting spiral cylinder 692 includes a conveying pipe 693, a spiral feeding rod 694 arranged in the conveying pipe 693 and a feeding motor 695 for driving the spiral feeding rod 694 to rotate. The discharge pipe 696 connects the upper end of the conveying pipe 693 and the grinding media hopper 61, aiming to transport the grinding media screened by the screening mechanism 4 upward into the grinding media hopper 61.

[0054] Regarding cooling and heat dissipation, traditional sand mills only set cooling water outside the grinding cylinder 1 to perform water cooling on the outer wall of the grinding cylinder 1. However, the inventor found that the heat generated by the stirring mechanism 2 inside the grinding cylinder 1 needs to be transferred to the cooling water outside through the slurry and the inner wall of the grinding cylinder 1, and its heat transfer efficiency is low. Most of the heat is generated in the inner rotating cylinder 21 during grinding. Thus, the external water cooling has a poor effect on internal heat dissipation, and too high a temperature will greatly reduce the grinding efficiency. Therefore, the present invention makes further innovations in heat dissipation and cooling:

[0055] The grinding cylinder 1 is provided with an external heat dissipation structure 7, which includes a water jacket 71 covering the outside of the grinding cylinder 1. An external cooling channel 72 is formed between the water jacket 71 and the grinding cylinder 1. The external cooling channel 72 is provided with an external cooling water inlet pipe 73 and an external cooling drain pipe 74. The coolant flowing into the external cooling water inlet pipe 73 flows out from the external cooling drain pipe 74 after passing through the external cooling channel 72, thereby taking away the heat from the side wall of the grinding cylinder 1.

[0056] The stirring mechanism 2 is provided with an internal heat dissipation structure 8, which includes an inner sleeve 81 inserted into the main shaft 22. An internal cooling water inlet channel is opened inside the inner sleeve 81. A water guide cap 82 is provided at the rear end of the inner sleeve 81. The water guide cap 82 is provided with a radially extending channel 83 communicating with the internal cooling water inlet channel. An annular internal cooling water outlet channel 84 is provided between the inner sleeve 81 and the main shaft 22. One end of the internal cooling water outlet channel 84 communicates with the inner front end of the inner rotating cylinder 21. The other end of the internal cooling water outlet channel 84 penetrates outside the grinding cylinder 1 and is connected with an internal cooling drain wheel 85. The internal channel of the internal cooling drain wheel 85 passes through the main shaft 22 and communicates with the internal cooling water outlet channel 84. The internal cooling drain wheel 85 is fixed to the main shaft 22, and its outer periphery is surrounded by a water collecting cover 86. The water collecting cover 86 is provided with an internal cooling drain pipe 87. The outer end of the internal cooling water inlet channel introduces the coolant, which enters the inside of the inner rotating cylinder 21 from the radially extending channel 83. Under the rotational force of the inner rotating cylinder 21, the coolant preferentially makes close contact with the inner wall of the inner rotating cylinder 21 to absorb heat, and then flows out from the internal cooling water outlet channel 84, and is discharged through the internal cooling drain wheel 85, the water collecting cover 86, and the internal cooling drain pipe 87.

[0057] In this embodiment, ultrasonic transmitters 9 are respectively provided on both inner end faces of the grinding cylinder 1. The ultrasonic transmitters 9 are aligned with the grinding channels 12. The function is to generate bubbles in the water. The stress generated by the expansion and explosion of the bubbles breaks the particles in the pulp. Combined with the mechanical grinding of the grinding medium, the grinding efficiency is improved.

[0058] For the protection of the ultrasonic sound generator, since the hardness of the grinding medium is very high, if the grinding medium contacts the ultrasonic transmitter 9, it is easily worn out. In order to avoid the impact damage of the grinding medium on the ultrasonic sound generator, the present invention innovates the following measures:

[0059] The position of the pulp outlet is optimized. The pulp outlet is not located at the rear end face of the grinding cylinder 1, but is optimally arranged near the rear end of the side wall of the grinding cylinder 1, that is Figure 1 or Figure 2 to the right of the leftmost moving pin column 25 in Figure 2 In this way, most of the grinding medium flows out before contacting the ultrasonic sound generator on the left side. For

[0060] In this embodiment, the movable pin 25 close to the ultrasonic transmitter 9 is arranged tilted away from the ultrasonic transmitter 9. Figure 2 and Figure 3 As shown, located Figure 2 The leftmost and / or rightmost movable pin 25 is inclined toward the middle, so that after the grinding medium contacts and collides with the pin, it is subjected to a force away from the ultrasonic sound generator, thereby preventing the grinding medium from colliding with the ultrasonic sound generator. In practice, the static pin 13 can also be arranged to be inclined in the same way to achieve a similar effect.

[0061] Furthermore, a medium retaining mechanism 10 is provided at the rear end of the grinding cylinder 1, which includes a medium retaining pump 101, a medium retaining tube 102 and a rear homogenizing fan 103. The medium retaining pump 101 connects the slurry cylinder 51 and the rear end of the grinding cylinder 1 through the medium retaining tube 102. The rear homogenizing fan 103 is fixed to the outer side of the rear end of the inner rotating cylinder 21. The medium retaining pump 101 conveys the slurry in the slurry cylinder 51 to the rear end of the grinding cylinder 1 (the space between the rear end surface of the grinding cylinder 1 and the rear end surface of the inner rotating cylinder 21) under high pressure. On the left and right of the rear homogenizing fan 103, the slurry flows radially toward the grinding channel 12, blocking the forward impact force of the grinding medium at the rear end of the grinding channel 12, so that all the grinding medium flows out from the slurry outlet, further preventing the grinding medium from colliding with the ultrasonic emitter, thereby ensuring the life of the ultrasonic emitter 9.

[0062] The working principle of the present invention is as follows: when in use, the grinding medium adding device 6 adds grinding medium to the front end of the grinding channel 12, and the main slurry pump 32 inputs the slurry to be ground from the slurry inlet 11 of the grinding cylinder 1, wherein the ratio of the entering grinding medium and the slurry to be ground can be pre-adjusted by the flow rate, and under the stirring of the moving pin 25 and the static pin 13 of the stirring mechanism 2, the grinding medium collides and shears with each other in the grinding channel 12 to grind the slurry, and after reaching the slurry outlet, the grinding medium and the ground slurry flow out from the slurry outlet of the grinding cylinder 1, and are vibrated and separated at the screening mechanism 4, and the ground slurry enters the slurry forming cylinder 51 for collection, and the separated grinding medium circulates back to the grinding medium bucket 61 of the grinding medium adding device 6 via the grinding medium lifting mechanism 69, and the cycle is repeated.

[0063] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention, rather than to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

Claims

1. A sand grinding system with recycled grinding media, comprising a grinding cylinder and a stirring mechanism. The grinding cylinder is provided with a slurry inlet and a slurry outlet, and a grinding channel connecting the slurry inlet and the slurry outlet is arranged inside the grinding cylinder. The stirring mechanism agitates the grinding media in the grinding channel. It is characterized in that: The sand grinding system further comprises a grinding media adding device and a screening mechanism. The screening mechanism is located outside the grinding cylinder. The grinding media adding device adds grinding media into the grinding channel from the front end of the grinding cylinder. Under the action of the ore slurry flowing in from the slurry inlet, the grinding media is discharged from the slurry outlet of the grinding cylinder to the screening mechanism, so as to separate the ground ore slurry from the grinding media. The sand grinding system further comprises a raw slurry tank, a main slurry pump and a main slurry pipe. The main slurry pump is connected to the raw slurry tank and the slurry inlet respectively through the main slurry pipe. The sand grinding system further comprises a finished slurry tank and a discharge pipe. The slurry outlet is connected to the finished slurry tank through the discharge pipe. The finished slurry tank is located below the screening mechanism to receive the ore slurry after filtering and separating the grinding media. The grinding media adding device comprises a grinding media hopper, a pressure medium slurry pipe, a valve housing, a valve core, a surplus slurry discharge pipe and a media inlet pipe. The media inlet pipe is connected to the front end of the grinding channel. The valve core is movably installed in the valve housing, and the valve core is provided with more than three channels. The valve housing moves so that different channels are successively connected to the grinding media hopper, the pressure medium slurry pipe and the media inlet pipe, and the surplus slurry discharge pipe. The raw slurry tank is provided with a pressure medium pump, and the pressure medium pump is connected to the pressure medium slurry pipe and the raw slurry tank respectively. The stirring mechanism comprises an inner rotating cylinder, a main shaft coaxially fixed with the inner rotating cylinder and a main motor for driving the main shaft to rotate. The inner rotating cylinder is arranged inside the grinding cylinder, and the grinding channel is formed between the outer wall of the inner rotating cylinder and the inner wall of the grinding cylinder. A plurality of moving pin columns distributed axially are arranged on the outer wall of the inner rotating cylinder, and a plurality of static pin columns distributed axially are arranged on the inner wall of the grinding cylinder. The static pin columns and the moving pin columns are arranged staggeredly in the circumferential direction in the grinding channel. The slurry inlet is located at the front end of the grinding cylinder, and a front slurry equalizing fan is arranged on the front end face of the inner rotating cylinder. An ultrasonic transmitter is arranged at the inner end of the grinding cylinder, and the ultrasonic transmitter is aligned with the grinding channel. The slurry outlet is located at the side wall of the grinding cylinder near the rear end. A media retaining mechanism is arranged at the rear end of the grinding cylinder, which comprises a media retaining pipe and a rear slurry equalizing fan. The media retaining pipe is connected to the rear end of the grinding cylinder, and the rear slurry equalizing fan is fixed to the outer side of the rear end of the inner rotating cylinder.

2. A sand grinding system with recycled grinding media according to claim 1, It is characterized in that: The grinding media adding device further comprises a grinding media lifting mechanism, which comprises a feeding hopper, a lifting screw barrel and a discharging pipe. The feeding hopper is located at the screening mechanism to receive the screened grinding media. The lifting screw barrel comprises a media conveying pipe, a screw feeding rod arranged in the media conveying pipe and a feeding motor for driving the screw feeding rod to rotate. The discharging pipe is connected to the upper end of the media conveying pipe and the grinding media hopper.

3. A sand grinding system with recycled grinding media according to claim 1, It is characterized in that: The grinding cylinder is provided with an external heat dissipation structure, which comprises a water jacket covering the outside of the grinding cylinder. An external cooling channel is formed between the water jacket and the grinding cylinder. The external cooling channel is provided with an external cooling water inlet pipe and an external cooling water discharge pipe. The stirring mechanism is provided with an internal heat dissipation structure, which comprises an inner sleeve arranged inside the main shaft. An internal cooling water inlet channel is opened inside the inner sleeve. A water guiding cap is arranged at the rear end of the inner sleeve, and the water guiding cap is provided with a radial extension channel communicating with the internal cooling water inlet channel. An inner cooling water outlet channel is provided between the inner sleeve and the main shaft. One end of the inner cooling water outlet channel communicates with the inner front end of the inner rotating cylinder. The other end of the inner cooling water outlet channel penetrates outside the grinding cylinder and is connected with an inner cooling drainage wheel. The inner cooling drainage wheel is fixed to the main shaft, and a water collecting cover surrounds its outer periphery. The water collecting cover is provided with an inner cooling drainage pipe.

4. A sand grinding system for recycling grinding media according to claim 1, characterized in that: The moving pin column and / or the static pin column near the ultrasonic transmitter are arranged obliquely away from the ultrasonic transmitter.

5. A sand grinding system for recycling grinding media according to claim 1, characterized in that: The screening mechanism includes a vibrating filter disc, an elastic support seat and a vibration driving member. The vibrating filter disc is fixed on the elastic support seat, and the vibration driving member drives the vibrating filter disc to vibrate.

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