A cylindrical pelletizer and its application

Abstract

The present invention provides a cylindrical pelletizing machine and its application. The cylindrical pelletizing machine includes a pelletizing cylinder, which is composed of at least one rotatable pelletizing sub-cylinder along its length direction. Both ends of the pelletizing sub-cylinder are open, and an annular baffle plate coaxial with the pelletizing sub-cylinder is fixedly sealed on the inner side wall of its discharge end; the outer circumference of the annular baffle plate is fixedly sealed and connected to the inner side wall of the pelletizing cylinder, and the pelletizing cylinder is arranged obliquely downward; the cylindrical pelletizing machine further includes a feeding mechanism for feeding each pelletizing sub-cylinder and a water adding mechanism for adding water. The cylindrical pelletizing machine of the present invention is suitable for producing ceramsite pellets with a multi-layer structure, and can carry out continuous production of the above-mentioned ceramsite pellets, with high production efficiency and low cost. The corresponding method is simple and easy to operate, and can effectively solve the difficulties existing in the preparation of lightweight ceramsite from heavy metal tailings at present.

Description

Technical Field

[0001] The present invention belongs to the technical field of pelletizing machines, and particularly relates to a cylindrical pelletizing machine and its application. Background Art

[0002] At present, pelletizing machines are widely used in industries such as metallurgy, cement, and ceramsite. Among them, the cylindrical pelletizing machine is a commonly used device for manufacturing green balls in the pellet production process. The cylindrical pelletizing machine is a cylindrical pelletizing device that makes fine-grained powdery materials into spherical materials with particle sizes meeting the requirements of the next operation, and is used for the production of iron ore pellets in the metallurgical industry and the pelletizing operation of non-ferrous metal mixed concentrates to improve the smelting technical and economic indicators. The pelletizing materials are subjected to the combined action of gravity, centrifugal force, and friction in the inclined and rotating cylinder to produce rolling and rubbing, and form mother balls after adding appropriate moisture. Fine-grained materials roll on the surface of the wet mother balls, causing the mother balls to grow and have a certain strength. Different pellets automatically run along different tracks in the cylinder, and the qualified finished pellets are discharged from the tray.

[0003] However, the current cylindrical pelletizing machine is not suitable for continuously preparing ceramsite pellets with a multi-layer structure when preparing ceramsite pellets. Therefore, it is of great significance to develop a new pelletizing machine and make it suitable for preparing ceramsite pellets with a multi-layer structure. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the above-mentioned deficiencies and defects in the background art, and provide a cylindrical pelletizing machine and its application.

[0005] To solve the above technical problem, the technical solution proposed by the present invention is as follows:

[0006] A cylindrical pelletizing machine includes a pelletizing cylinder, the pelletizing cylinder is composed of at least one rotatable pelletizing sub-cylinder along its length direction, both ends of the pelletizing sub-cylinder are open, and an annular baffle plate coaxial with the pelletizing sub-cylinder is hermetically fixed on the inner side wall of its discharge end; the outer circumference of the annular baffle plate is hermetically fixedly connected with the inner side wall of the pelletizing cylinder, and the pelletizing cylinder is arranged obliquely downward; the cylindrical pelletizing machine further includes a feeding mechanism for feeding each pelletizing sub-cylinder and a water adding mechanism for adding water.

[0007] Further, the pelletizing cylinder is composed of a plurality of pelletizing sub-cylinders along its length direction, and two adjacent pelletizing sub-cylinders 101 are hermetically and rotatably connected, and each pelletizing sub-cylinder is driven to rotate by a driving device.

[0008] Further, the inner diameter of the pelletizing sub-cylinder remains unchanged; along the direction in which the pelletizing cylinder is inclined downward, the inner diameters of multiple annular baffle plates decrease in sequence.

[0009] Further, except for the pelletizing sub-cylinder at the bottom, a sealing ring is fixed on the inner side wall of the discharging end of each of the other pelletizing sub-cylinders. The sealing ring is located outside the corresponding annular baffle plate; the outer end of the sealing ring extends into the adjacent lower pelletizing sub-cylinder, and a pressing ring is arranged between the sealing ring and the inner side wall of the adjacent lower pelletizing sub-cylinder. The pressing ring is fixedly connected to the pelletizing sub-cylinder, and the pressing ring is in pressing and rotational connection with the sealing ring.

[0010] Further, the driving device includes a fixed ring, a large gear, a small gear, a speed reducer, a motor, and a spring plate. The pelletizing sub-cylinder passes through the fixed ring and is fixedly connected to the fixed ring. A large gear coaxial with the fixed ring is arranged outside the fixed ring. The large gear is connected to the spring steel plate through a connecting rod, and the spring steel plate is connected to the outer side wall of the fixed ring. The output shaft of the motor is connected to the speed reducer, the output shaft of the speed reducer is fixedly connected to the small gear, and the small gear is meshed with the large gear.

[0011] Wheel belts are fixed on the pelletizing sub-cylinders on both sides of the large gear. The pelletizing sub-cylinder passes through the wheel belt and is fixedly connected to the wheel belt. Supporting wheels that are in rolling contact with the wheel belt are arranged on both sides below the wheel belt. Stop wheels for preventing the pelletizing sub-cylinder from moving along its axis are arranged on both sides of the wheel belt along the length direction of the pelletizing sub-cylinder.

[0012] Further, 3 - 8 guide plates are evenly fixed around the axis of the inner side wall of each pelletizing sub-cylinder, and the guide plates are inclined relative to the axis of the pelletizing sub-cylinder.

[0013] Further, in each pelletizing sub-cylinder, a feeding mechanism and a water adding mechanism are configured.

[0014] The feeding mechanism is a screw feeder. The screw feeder extends from the outer end of the pelletizing cylinder to the corresponding pelletizing sub-cylinder along the length direction of the pelletizing cylinder. The feeding end of the screw feeder is located outside the pelletizing cylinder, and the discharging end of the screw feeder is located in the corresponding pelletizing sub-cylinder.

[0015] The water adding mechanism includes a water inlet pipe. The water inlet pipe is fixed on the corresponding screw feeder and extends into the corresponding pelletizing sub-cylinder. At least one water mist nozzle is installed on the water inlet pipe in the pelletizing sub-cylinder.

[0016] Further, the difference between the outer diameter and the inner diameter of the annular baffle plate is 0.005 - 0.3 m, and the inner diameter of the pelletizing sub-cylinder is 1 - 5 m; the inclination angle of the pelletizing cylinder is 3 - 30°.

[0017] As a general inventive concept, the present invention provides an application of a cylindrical pelletizer, applying the cylindrical pelletizer to the preparation of ceramsite pellets, the ceramsite pellets including seed balls, and multiple coating layers are sequentially arranged outside the seed balls; raw materials for preparing the seed balls are conveyed to the topmost pelletizing sub-cylinder through a feeding mechanism, and raw materials for preparing the corresponding coating layers are respectively conveyed to other pelletizing sub-cylinders through the feeding mechanism; and water is added to each of the pelletizing sub-cylinders through a water adding mechanism for pelletizing, and each of the pelletizing sub-cylinders is driven to rotate through a driving device.

[0018] When the pellets prepared by each pelletizing sub-cylinder reach the target particle size, the obtained pellets cross the corresponding annular baffle plate to reach the next pelletizing sub-cylinder, and the ceramsite pellets prepared by the lowermost pelletizing sub-cylinder cross the corresponding annular baffle plate and are collected.

[0019] Further, applying the cylindrical pelletizer to the preparation of ceramsite pellets, the pelletizing cylinder is composed of 4 pelletizing sub-cylinders along its length direction, and from top to bottom, the 4 pelletizing sub-cylinders are respectively pelletizing sub-cylinder one, pelletizing sub-cylinder two, pelletizing sub-cylinder three, and pelletizing sub-cylinder four; a mixture of pore-forming agent and binder, a mixture of heavy metal tailings powder one and binder, a mixture of chemical composition regulator / heavy metal tailings powder two and binder, and a mixture of flux / heavy metal tailings powder three and binder are respectively conveyed to the multiple pelletizing sub-cylinders from top to bottom through a feeding mechanism, and water is added to each of the pelletizing sub-cylinders through a water adding mechanism for pelletizing, and each of the pelletizing sub-cylinders is driven to rotate through a driving device;

[0020] When the pellets prepared in pelletizing sub-cylinder one reach the target particle size, pore-forming agent seed balls are obtained; the pore-forming agent seed balls cross the corresponding annular baffle plate to reach pelletizing sub-cylinder two, and heavy metal tailings powder one adheres to the pore-forming agent seed balls. When the prepared pellets reach the target particle size, green balls I are obtained; the green balls I cross the corresponding annular baffle plate to reach pelletizing sub-cylinder three, and the chemical composition regulator and heavy metal tailings powder two adhere to the green balls I. When the prepared pellets reach the target particle size, green balls II are obtained; the green balls II cross the corresponding annular baffle plate to reach pelletizing sub-cylinder four, and the flux and heavy metal tailings powder three are attached to the green balls II. When the prepared pellets reach the target particle size, ceramsite pellets are obtained; the ceramsite pellets cross the corresponding annular baffle plate and are collected.

[0021] Further, in the raw materials for preparing ceramsite pellets, based on the total mass of the pore-forming agent, chemical composition regulator, flux, and heavy metal tailings powder being 100%, the pore-forming agent accounts for 5 - 15%, the chemical composition regulator accounts for 5 - 40%, the flux accounts for 5 - 15%, and the heavy metal tailings powder accounts for 40 - 85%; the heavy metal tailings powder includes heavy metal tailings powder one, heavy metal tailings powder two, and heavy metal tailings powder three;

[0022] The particle size range of the pore-forming agent master balls is 2-6 mm; the pore-forming agent includes at least one of an organic pore-forming agent and an inorganic pore-forming agent; the heavy metal tailings powder includes at least one of copper tailings, lead tailings, zinc tailings, gold tailings, silver tailings, cadmium tailings, and chromium tailings; the chemical composition regulator includes quartz; the flux includes one or more of porcelain stone, fly ash, and zeolite.

[0023] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0024] 1. The cylindrical pelletizer of the present invention is suitable for producing ceramsite pellets with a multi-layer structure. It can carry out continuous production of the above-mentioned ceramsite pellets, with high production efficiency, low cost, and a corresponding simple method, easy to operate, and can effectively solve the difficulties existing in the preparation of lightweight ceramsite from heavy metal tailings at present.

[0025] 2. The pelletizing cylinder of the cylindrical pelletizer of the present invention can be composed of a plurality of pelletizing sub-cylinders along its length direction. Adjacent two pelletizing sub-cylinders are sealed and rotatably connected, and each pelletizing sub-cylinder is driven to rotate by a corresponding driving device. Thus, the rotation speed of different pelletizing sub-cylinders can be adjusted according to the actual process, making the centrifugal force and the like of the material in each pelletizing sub-cylinder more suitable, making the quality of the prepared ceramsite pellets better, and increasing the production efficiency.

[0026] 3. By setting the guide plate, during the rotation of the pelletizing cylinder, it can prevent the material in the pelletizing area from accumulating at the bottom of the pelletizing cylinder, making the material more dispersed. And the guide plate is inclined relative to the axis line of the pelletizing cylinder, which can make the remaining material on the guide plate slide back into the pelletizing cylinder. Description of the Drawings

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0028] Figure 1 It is a cross-sectional view of the cylindrical pelletizer;

[0029] Figure 2 It is a three-dimensional structure diagram of the pelletizing cylinder;

[0030] Figure 3 It is for Figure 1 The enlarged view at A in

[0031] Figure 4 It is for Figure 1 The partial structure diagram of

[0032] Figure 5 It is a structure diagram of the annular baffle plate;

[0033] Figure 6 It is a schematic external structure diagram of a cylindrical pelletizing machine;

[0034] Figure 7 It is a schematic partial structure diagram of a driving device;

[0035] Figure 8 It is another schematic partial structure diagram of the driving device;

[0036] Figure 9 It is a schematic three-dimensional structure diagram of a pelletizing cylinder during application.

[0037] Legend Explanation:

[0038] 1. Pelletizing cylinder; 101. Pelletizing sub-cylinder; 1011. Pelletizing sub-cylinder one; 1012. Pelletizing sub-cylinder two; 1013. Pelletizing sub-cylinder three; 1014. Pelletizing sub-cylinder four; 2. Annular baffle plate; 3. Feeding mechanism; 4. Water adding mechanism; 401. Water inlet pipe; 402. Water mist nozzle; 5. Driving device; 501. Fixed ring; 502. Large gear; 503. Small gear; 504. Reducer; 505. Motor; 6. Sealing ring; 7. Compression ring; 8. Rim; 9. Supporting roller; 10. Retaining wheel; 11. Guide plate. Specific Embodiment

[0039] For the convenience of understanding the present invention, the following will describe the present invention more comprehensively and meticulously in combination with the accompanying drawings of the specification and preferred embodiments, but the protection scope of the present invention is not limited to the following specific embodiments.

[0040] Unless otherwise defined, all professional terms used hereinafter have the same meaning as commonly understood by those skilled in the art. The professional terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the protection scope of the present invention.

[0041] Unless otherwise specifically stated, various raw materials, reagents, instruments, and equipment used in the present invention can be obtained through market purchase or can be prepared by existing methods.

[0042] Embodiment 1:

[0043] As Figures 1-9 shown, a cylindrical pelletizing machine includes a pelletizing cylinder 1, the pelletizing cylinder 1 is composed of at least one rotatable pelletizing sub-cylinder 101 along its length direction, both ends of the pelletizing sub-cylinder 101 are open, and an annular baffle plate 2 coaxial with the pelletizing sub-cylinder 101 is fixedly sealed on the inner side wall of its discharge end; the outer periphery of the annular baffle plate 2 is fixedly sealed and connected to the inner side wall of the pelletizing cylinder 1, and the pelletizing cylinder 1 is arranged obliquely downward; the cylindrical pelletizing machine further includes a feeding mechanism 3 for feeding each pelletizing sub-cylinder 101 and a water adding mechanism 4 for adding water.

[0044] In this embodiment, each pelletizing sub-cylinder 101 is a relatively independent pelletizing area. Generally, the mother balls (nuclei) of the pellets are prepared using the uppermost pelletizing sub-cylinder 101. When the pelletizing sub-cylinder 101 rotates, the pelletizing materials it contains, during the rotation process, through the combined action of various forces, combined with the water supplemented by the water adding mechanism 4, prepare mother balls with appropriate particle sizes. Only after the particle size of the mother balls meets the standard can they cross the corresponding annular baffle 2 and enter the next pelletizing sub-cylinder 101. The materials for preparing the coating layer combine various forces and water, and then coat the outer layer of the mother balls. When the particle size meets the standard, they cross the corresponding annular baffle 2 again and enter the next pelletizing cylinder 1 for coating layer coating, and finally obtain pellets with a multi-layer structure.

[0045] The feeding mechanism 3 in this embodiment is mainly used to add powder materials to each pelletizing sub-cylinder 101, and the water adding mechanism 4 supplements appropriate moisture for preparing the mother balls or the coating layer. The drum pelletizer in this embodiment can carry out the continuous production of the above-mentioned pellets, with high production efficiency and low cost.

[0046] In this embodiment, the pelletizing cylinder 1 can be an integral cylinder structure, and the driving device drives the whole pelletizing cylinder 1 to rotate. This driving device can be a conventional driving device for driving the cylinder to rotate by itself in the art.

[0047] Furthermore, to improve the pelletizing performance, in the drum pelletizer of this embodiment, the pelletizing cylinder 1 is composed of a plurality of pelletizing sub-cylinders 101 along its length direction. Adjacent two pelletizing sub-cylinders 101 are hermetically and rotationally connected, and each pelletizing sub-cylinder 101 is driven to rotate by a driving device 5. Through the above settings, each pelletizing sub-cylinder 101 is driven to rotate by the corresponding driving device 5, so that the rotation speed of different pelletizing sub-cylinders 101 can be adjusted according to the actual process, making the centrifugal force of the materials in each pelletizing sub-cylinder 101 more appropriate, making the quality of the prepared pellets better, and increasing the production efficiency.

[0048] In this embodiment, the inner diameter of the pelletizing sub-cylinder 101 remains unchanged; along the direction of the inclined downward of the pelletizing cylinder 1, the inner diameters of multiple annular baffles 2 decrease in sequence. The inner diameter of the pelletizing sub-cylinder 101 remains unchanged, which can be considered that the overall inner diameter of the pelletizing cylinder 1 remains unchanged. And along the direction of the inclined downward of the pelletizing cylinder 1, the inner diameters of multiple annular baffles 2 decrease in sequence, which means that the difference between the outer diameter and the inner diameter of multiple annular baffles 2 increases in sequence. The lower the position, the larger the particle size of the pellets that can cross the corresponding annular baffle 2. In this embodiment, when the pellets prepared by each pelletizing sub-cylinder 101 reach the target particle size, they can cross the corresponding annular baffle 2 and enter the next pelletizing sub-cylinder 101, otherwise they will be blocked by the annular baffle 2 and continue to coat the raw materials in the pelletizing sub-cylinder 101 where they are located until the particle size meets the standard.

[0049] In this embodiment, except for the pelletizing sub-cylinder 101 at the bottommost position, a sealing ring 6 is fixed on the inner side wall of the discharge end of other pelletizing sub-cylinders 101. The sealing ring 6 is located outside the corresponding annular baffle 2. The outer end of the sealing ring 6 extends into the adjacent lower pelletizing sub-cylinder 101. A pressing ring 7 is arranged between the sealing ring 6 and the inner side wall of the adjacent lower pelletizing sub-cylinder 101. The pressing ring 7 is fixedly connected to the pelletizing sub-cylinder 101, and the pressing ring 7 is in pressing and rotating connection with the sealing ring 6.

[0050] By arranging the sealing ring 6 and the pressing ring 7, the sealing performance between adjacent pelletizing sub-cylinders 101 is good, and elastic-shaped sealed rotating connection can be achieved. During the working process, the drum pelletizer can work more stably and has a longer service life.

[0051] In this embodiment, the driving device 5 includes a fixing ring 501, a large gear 502, a small gear 503, a speed reducer 504, a motor 505, and a spring plate. The pelletizing sub-cylinder 101 passes through the fixing ring 501 and is fixedly connected to the fixing ring 501. A coaxial large gear 502 is arranged outside the fixing ring 501. The large gear 502 is connected to the spring steel plate through a connecting rod, and the spring steel plate is connected to the outer side wall of the fixing ring 501. The output shaft of the motor 505 is connected to the speed reducer 504, and the output shaft of the speed reducer 504 is fixedly connected to the small gear 503. The small gear 503 is meshed with the large gear 502;

[0052] Wheel belts 8 are fixed on the pelletizing sub-cylinders 101 on both sides of the large gear 502. The pelletizing sub-cylinder 101 passes through the wheel belt 8 and is fixedly connected to the wheel belt 8. Supporting wheels 9 that are in rolling contact with the wheel belt 8 are arranged on both sides below the wheel belt 8. Stop wheels 10 for preventing the pelletizing sub-cylinder 101 from moving along its axis are arranged on both sides of the wheel belt 8 along the length direction of the pelletizing sub-cylinder 101.

[0053] The above driving device 5 can achieve stable driving of each pelletizing sub-cylinder 101, and the arrangements of the wheel belt 8, the supporting wheel 9, the stop wheel 10, etc. can make the pelletizing sub-cylinder 101 more stable during the working process. The above speed reducer 504, motor 505, supporting wheel 9, and stop wheel 10 are all fixed on the corresponding supports.

[0054] In this embodiment, 3 - 8 guide plates 11 are uniformly fixed on the inner side wall of each pelletizing sub-cylinder 101 around the axis of the pelletizing sub-cylinder 101. The guide plates 11 are inclined with respect to the axis of the pelletizing sub-cylinder 101.

[0055] By setting up the material guiding plate 11, during the rotation of the pelletizing drum 101, the accumulation of materials in the pelletizing area at the bottom of the pelletizing drum 101 can be prevented, making the materials more dispersed. The material guiding plate 11 is inclined relative to the axis line of the pelletizing drum 101, which can make the residual materials on the material guiding plate 11 slide back into the pelletizing drum 101. Moreover, the height of the material guiding plate 11 in the radial direction of the pelletizing drum 101 is lower than the height where the inner diameter of the corresponding annular baffle plate 2 is located.

[0056] In this embodiment, within each pelletizing drum 101, a set of feeding mechanism 3 and a set of water adding mechanism 4 are arranged;

[0057] The feeding mechanism 3 is a screw feeder. The screw feeder extends from the outer end of the pelletizing drum 1 along the length direction of the pelletizing drum 1 into the corresponding pelletizing drum 101. The feeding end of the screw feeder is located outside the pelletizing drum 1, and the discharging end of the screw feeder is located in the corresponding pelletizing drum 101; The screw feeder is arranged suspended as a whole and is supported by a corresponding bracket (the bracket is not shown in the figure).

[0058] The water adding mechanism 4 includes a water inlet pipe 401. The water inlet pipe 401 is fixed on the corresponding screw feeder and extends into the corresponding pelletizing drum 101. At least one water mist nozzle 402 is installed on the water inlet pipe 401 in the pelletizing drum 101.

[0059] The above feeding mechanism 3 and water adding mechanism 4 have simple structures, are easy to enter each pelletizing area, and are convenient to operate.

[0060] In this embodiment, the difference between the outer diameter and the inner diameter of the annular baffle plate 2 is 0.005 - 0.3 m, and the inner diameter of the pelletizing drum 101 is 1 - 5 m; The inclination angle of the pelletizing drum 1 is 3 - 30°.

[0061] In this embodiment, baffle structures (not shown in the figure) can be arranged at both ends of the pelletizing drum 1 to prevent the influence of the pelletizing drum 1 on the environment.

[0062] Embodiment 2:

[0063] An application of a cylindrical pelletizing machine, specifically applying the cylindrical pelletizing machine in Embodiment 1 to prepare ceramsite pellets. The ceramsite pellets include mother balls, and multiple coating layers are sequentially arranged outside the mother balls; The raw materials for preparing the mother balls are conveyed to the uppermost pelletizing drum 101 through the feeding mechanism 3, and the raw materials for preparing the corresponding coating layers are respectively conveyed to other pelletizing drums 101 through the feeding mechanism 3; And water is added to each pelletizing drum 101 through the water adding mechanism 4 for pelletizing, and each pelletizing drum 101 is driven to rotate by a driving device 5;

[0064] After the pellets prepared by each pelletizing sub-cylinder 101 reach the target particle size, the obtained pellets cross the corresponding annular baffle plate and reach the next pelletizing sub-cylinder 101. The ceramsite pellets prepared by the lowermost pelletizing sub-cylinder 101 cross the corresponding annular baffle plate and are collected.

[0065] The following is a specific preparation method for ceramsite pellets, including the following steps:

[0066] (1) The pelletizing cylinder 1 is composed of 4 pelletizing sub-cylinders 101 along its length direction. From top to bottom, the 4 pelletizing sub-cylinders 101 are respectively the first pelletizing sub-cylinder 1011, the second pelletizing sub-cylinder 1012, the third pelletizing sub-cylinder 1013, and the fourth pelletizing sub-cylinder 1014; a mixture of pore-forming agent and binder, a mixture of heavy metal tailings powder one and binder, a mixture of chemical composition adjuster / heavy metal tailings powder two and binder, and a mixture of flux / heavy metal tailings powder three and binder are respectively conveyed to the 4 pelletizing sub-cylinders 101 from top to bottom through the feeding mechanism 3, and water is added to each pelletizing sub-cylinder 101 through the water adding mechanism 4 to form pellets, and each pelletizing sub-cylinder 101 is driven to rotate by the driving device 5;

[0067] (2) After the pellets prepared in the first pelletizing sub-cylinder 1011 reach the target particle size, the pore-forming agent mother balls are obtained; the pore-forming agent mother balls cross the corresponding annular baffle plate 2 and reach the second pelletizing sub-cylinder 1012, and the heavy metal tailings powder one is adhered to the pore-forming agent mother balls in the second pelletizing sub-cylinder 1012. After the prepared pellets reach the target particle size, the green balls I are obtained; the green balls I cross the corresponding annular baffle plate 2 and reach the third pelletizing sub-cylinder 1013, and the chemical composition adjuster and the heavy metal tailings powder two are adhered to the green balls I in the third pelletizing sub-cylinder 1013. After the prepared pellets reach the target particle size, the green balls II are obtained; the green balls II cross the corresponding annular baffle plate 2 and reach the fourth pelletizing sub-cylinder 1014, and the flux and the heavy metal tailings powder three are adhered to the green balls II in the fourth pelletizing sub-cylinder 1014. After the prepared pellets reach the target particle size, the ceramsite pellets are obtained; the ceramsite pellets cross the corresponding annular baffle plate 2 and are collected.

[0068] Among the raw materials for preparing the above-mentioned ceramsite pellets, based on the total mass of the pore-forming agent, chemical composition adjuster, flux, and heavy metal tailings powder being 100%, the pore-forming agent accounts for 5-15%, the chemical composition adjuster accounts for 5-40%, the flux accounts for 5-15%, and the heavy metal tailings powder accounts for 40-85%; the heavy metal tailings powder includes heavy metal tailings powder one, heavy metal tailings powder two, and heavy metal tailings powder three, and the proportions of heavy metal tailings powder one, heavy metal tailings powder two, and heavy metal tailings powder three in the heavy metal tailings powder can be 15-35%, 15-55%, and the balance respectively.

[0069] In the above preparation method, the particle size range of the pore-forming agent mother balls can be 2-6 mm; for the particle sizes of the green balls I, balls II, and ceramsite pellets, they are determined according to the specific particle size range of the actual pore-forming agent mother balls and the specific formulation amounts of the raw materials of each layer, and then the difference between the outer diameter and the inner diameter of the corresponding annular baffle is set. During the subsequent high-temperature roasting process of the ceramsite pellets in this embodiment, the pore-forming agent in the inner center continuously erupts and expands outward, which is conducive to the formation of a pore structure, forming a ceramsite product with well-developed pores, and can minimize the density of the ceramsite product based on heavy metal tailings, thus meeting the requirements of national standards.

[0070] The pore-forming agent includes at least one of an organic pore-forming agent and an inorganic pore-forming agent. The organic pore-forming agent includes at least one of natural plant fibers, natural plant polysaccharides, and high molecular polymers. The inorganic pore-forming agent includes at least one of combustible pore-forming agents, mineral pore-forming agents, and high-temperature decomposable salt pore-forming agents. The natural plant fibers include at least one of sawdust, cellulose, rice husk, and fruit shell. The natural plant polysaccharides include starch. The high molecular polymers include polyvinyl alcohol. The combustible pore-forming agents include at least one of charcoal and graphite. The mineral pore-forming agents include at least one of pulverized coal, perlite, zeolite, and limestone. The high-temperature decomposable salt pore-forming agents include at least one of ammonium chloride and ammonium carbonate.

[0071] The heavy metal tailings powder includes at least one of copper tailings, lead tailings, zinc tailings, gold tailings, silver tailings, cadmium tailings, and chromium tailings. The chemical composition adjuster includes quartz. The flux includes one or more of porcelain stone, fly ash, and zeolite. The main mineral components of porcelain stone are quartz, sericite, and feldspar. The main components of fly ash are oxides of silicon, aluminum, iron, calcium, and magnesium. The specific surface area of fly ash is 400-1200 m 2 / kg, and the content of vitreous body in fly ash > 40%. The total mass fraction of SiO2 and Al2O3 in zeolite is above 80%, and SiO2 / Al2O3 > 6.

[0072] The binder used in each step of preparing the ceramsite pellets includes one or several of bentonite, humic acid, and sodium silicate.

Claims

1. Application of a cylindrical pelletizing machine, characterized in that, The drum pelletizer includes a pelletizing drum (1), which is composed of 4 rotatable pelletizing sub - drums (101) along its length direction. From top to bottom, the 4 pelletizing sub - drums (101) are respectively the first pelletizing sub - drum (1011), the second pelletizing sub - drum (1012), the third pelletizing sub - drum (1013), and the fourth pelletizing sub - drum (1014); two adjacent pelletizing sub - drums (101) are hermetically and rotationally connected, and each pelletizing sub - drum (101) is driven to rotate by a driving device (5). Both ends of the pelletizing sub - drum (101) are open, and an annular baffle plate (2) co - axial with the pelletizing sub - drum (101) is hermetically fixed on the inner side wall of its discharge end; the outer circumference of the annular baffle plate (2) is hermetically and fixedly connected to the inner side wall of the pelletizing drum (1), and the pelletizing drum (1) is inclined downward; the inner diameter of the pelletizing sub - drum (101) remains unchanged; along the direction of the downward inclination of the pelletizing drum (1), the inner diameters of multiple annular baffle plates (2) decrease in sequence. On the inner side wall of each pelletizing sub - drum (101), 3 - 8 guide plates (11) are uniformly fixed around the axis of the pelletizing sub - drum (101), and the guide plates (11) are inclined with respect to the axis of the pelletizing sub - drum (101). The drum pelletizer also includes a feeding mechanism (3) for feeding each pelletizing sub - drum (101) and a water - adding mechanism (4) for adding water. The drum pelletizer is applied to the preparation of ceramsite pellets, and the ceramsite pellets include seed balls, and multiple coating layers are sequentially arranged outside the seed balls. Through the corresponding feeding mechanism (3), a mixture of pore - forming agent and binder, a mixture of heavy metal tailings powder one and binder, a mixture of chemical composition regulator / heavy metal tailings powder two and binder, and a mixture of flux / heavy metal tailings powder three are respectively transported to the 4 pelletizing sub - drums (101) from top to bottom, and water is added to each pelletizing sub - drum (101) through the water - adding mechanism (4) to form pellets. When the pellets prepared in the first pelletizing sub - drum (1011) reach the target particle size, the pore - forming agent seed balls are obtained; the pore - forming agent seed balls cross the corresponding annular baffle plate (2) and reach the second pelletizing sub - drum (1012), and the heavy metal tailings powder one is adhered to the pore - forming agent seed balls. When the prepared pellets reach the target particle size, the green balls I are obtained; the green balls I cross the corresponding annular baffle plate (2) and reach the third pelletizing sub - drum (1013), and the chemical composition regulator and heavy metal tailings powder two are adhered to the green balls I. When the prepared pellets reach the target particle size, the green balls II are obtained; the green balls II cross the corresponding annular baffle plate (2) and reach the fourth pelletizing sub - drum (1014), and the flux and heavy metal tailings powder three are adhered to the green balls II. When the prepared pellets reach the target particle size, the ceramsite pellets are obtained; the ceramsite pellets cross the corresponding annular baffle plate (2) and are collected.

2. The application of the cylindrical pelletizer according to claim 1, characterized in that, Except for the pelletizing sub-cylinder (101) at the bottommost, a sealing ring (6) is fixed on the inner sidewall of the discharge end of each of the other pelletizing sub-cylinders (101). The sealing ring (6) is located outside the corresponding annular baffle plate (2); the outer end of the sealing ring (6) extends into the adjacent lower pelletizing sub-cylinder (101), and a pressing ring (7) is provided between the sealing ring (6) and the inner sidewall of the adjacent lower pelletizing sub-cylinder (101). The pressing ring (7) is fixedly connected to the pelletizing sub-cylinder (101), and the pressing ring (7) is in pressing and rotational connection with the sealing ring (6).

3. The application of the cylindrical pelletizing machine according to claim 1, wherein, The driving device (5) includes a fixed ring (501), a large gear (502), a small gear (503), a speed reducer (504), a motor (505), and a spring plate. The pelletizing sub-cylinder (101) passes through the fixed ring (501) and is fixedly connected to the fixed ring (501). An axially concentric large gear (502) is provided outside the fixed ring (501). The large gear (502) is connected to the spring steel plate through a connecting rod, and the spring steel plate is connected to the outer sidewall of the fixed ring (501). The output shaft of the motor (505) is connected to the speed reducer (504), and the output shaft of the speed reducer (504) is fixedly connected to the small gear (503). The small gear (503) is meshed with the large gear (502); Wheel belts (8) are fixed on the pelletizing sub-cylinders (101) on both sides of the large gear (502). The pelletizing sub-cylinder (101) passes through the wheel belt (8) and is fixedly connected to the wheel belt (8). Supporting wheels (9) that are in rolling contact with the wheel belt (8) are provided on both sides below the wheel belt (8). Stop wheels (10) for preventing the pelletizing sub-cylinder (101) from moving along its axial direction are provided on both sides of the wheel belt (8) along the length direction of the pelletizing sub-cylinder (101).

4. Use of the cylindrical pelletizing machine according to any one of claims 1-3, characterized in that, In each pelletizing sub-cylinder (101), a feeding mechanism (3) and a water adding mechanism (4) are configured; The feeding mechanism (3) is a screw feeder. The screw feeder extends from the outer end of the pelletizing cylinder (1) to the corresponding pelletizing sub-cylinder (101) along the length direction of the pelletizing cylinder (1). The feeding end of the screw feeder is located outside the pelletizing cylinder (1), and the discharging end of the screw feeder is located in the corresponding pelletizing sub-cylinder (101); The water adding mechanism (4) includes a water inlet pipe (401). The water inlet pipe (401) is fixed on the corresponding screw feeder and extends into the corresponding pelletizing sub-cylinder (101). At least one water mist nozzle (402) is installed on the water inlet pipe (401) in the pelletizing sub-cylinder (101).

5. Use of the drum pelletizer according to any one of claims 1-3, characterized in that, The difference between the outer diameter and the inner diameter of the annular baffle plate (2) is 0.005 - 0.3 m, and the inner diameter of the pelletizing sub-cylinder (101) is 1 - 5 m; the inclination angle of the pelletizing cylinder (1) is 3 - 30°.

6. Use of the cylindrical pelletizer according to any one of claims 1-3, characterized in that In the raw materials for preparing ceramsite pellets, based on the total mass of pore-forming agent, chemical composition regulator, flux, and heavy metal tailings powder being 100%, the pore-forming agent accounts for 5 - 15%, the chemical composition regulator accounts for 5 - 40%, the flux accounts for 5 - 15%, and the heavy metal tailings powder accounts for 40 - 85%; the heavy metal tailings powder includes heavy metal tailings powder one, heavy metal tailings powder two, and heavy metal tailings powder three; The particle size range of the pore-forming agent mother balls is 2 - 6 mm; the pore-forming agent includes at least one of organic pore-forming agents and inorganic pore-forming agents; the heavy metal tailings powder includes at least one of copper tailings, lead tailings, zinc tailings, gold tailings, silver tailings, cadmium tailings, and chromium tailings; the chemical composition regulator includes quartz; the flux includes one or more of porcelain stone, fly ash, and zeolite.

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