Apparatus and method for producing zinc oxide by a direct process in a tunnel kiln in stages

Abstract

This invention relates to the field of non-ferrous metal smelting technology, and discloses a tunnel kiln for graded production of direct zinc oxide. The kiln includes: a gas supply system, a feeding system, a forced-air cooling system, and a waste residue return system; a controller fixed at the front end of the kiln; a feeding pipe fixed at the front end of the kiln; a steam pipe fixed at the rear end of the kiln; a transfer pipe fixed to the steam pipe; a centrifugal fan with its base fixed to the kiln and its working end fixed to the transfer pipe; and a reaction vessel fixed to the end of the transfer pipe furthest from the kiln. This invention utilizes an integrated rotary reaction cylinder design, combined with a special horn-shaped, gradually expanding inner bore structure inside the reaction cylinder, to allow the zinc vapor and air mixing reaction gas flow to achieve natural gradient deceleration during directional flow. This eliminates the need for additional independent deceleration and settling equipment, and the large-diameter zinc oxide particles generated by the oxidation reaction can be rapidly separated by gravity settling due to their own weight.

Description

Technical Field

[0001] This invention relates to the field of non-ferrous metal smelting technology, specifically to a tunnel kiln for graded production of direct zinc oxide. Background Technology

[0002] Tunnel kilns are the mainstream and commonly used equipment for the large-scale production of direct zinc oxide. At present, the production process and supporting equipment for the direct zinc oxide preparation using tunnel kilns have technical shortcomings in actual industrial production operations. Overall, there are problems such as low zinc oxide production efficiency, poor product quality stability, and low raw material resource recycling rate. Traditional tunnel kilns generally employ an integrated heating structure without a dedicated gradient temperature control layout for separate preheating and heating zones. Zinc ingots are directly introduced into the high-temperature heating zone for melting and vaporization, lacking a gradual preheating and activation process. This structure not only results in significant overall heat loss and low overall heat utilization efficiency but also easily leads to uneven melting and vaporization of the zinc ingots. This causes large fluctuations in zinc vapor concentration and output rate, making it impossible to maintain stable oxidation reaction conditions and directly impacting the basic quality of the finished zinc oxide product. Existing conventional production equipment requires separate installation of independent oxidation reaction units, particle deceleration and sedimentation devices, and coarse and fine particle classification and screening devices. The oxidation reaction process and particle classification and sorting operations are set up independently, resulting in a cumbersome and redundant overall production process with a large number of auxiliary equipment. This not only significantly increases the cost of equipment infrastructure investment and daily operation and maintenance, but also easily leads to problems such as poor process coordination and insufficient production continuity when multiple pieces of equipment are operating in tandem. Existing equipment only has a simple air-cooled heat dissipation structure for the zinc oxide oxidation reaction cylinder. The heat dissipation and heat exchange methods are limited, the effective heat dissipation contact area is small, and the heat dissipation and cooling intensity cannot be dynamically adjusted according to the real-time operating conditions of the oxidation reaction. Local high temperatures and uneven overall temperature distribution are prone to occur inside the reaction cylinder, making it difficult to accurately control the temperature of the oxidation reaction process. Summary of the Invention

[0003] This invention provides a device and method for the graded production of direct zinc oxide in a tunnel kiln, which greatly simplifies the overall production process.

[0004] To solve the above-mentioned technical problems, the technical solution of the present invention is as follows: In a first aspect, a tunnel kiln for graded production of direct-process zinc oxide is disclosed, comprising: a kiln equipped with a gas supply system, a material feeding system, a forced-air cooling system, and a waste residue recycling system, characterized in that it further comprises: The controller is fixed at the front end of the kiln; the feeding pipe is fixed at the front end of the kiln; the steam pipe is fixed at the rear end of the kiln; the transfer pipe is fixed on the steam pipe; the centrifugal fan has its base fixed on the kiln and its working end fixed on the transfer pipe; the reaction vessel is fixed on the end of the transfer pipe away from the kiln; the recovery vessel is fixed on the reaction vessel; the converging cone has its flared end rotatably mounted on the reaction vessel; and the cyclone separator is fixed on the converging end of the converging cone. The preheating zone is located at the front end of the kiln; the heating zone is located at the rear end of the kiln. A negative pressure cylinder is fitted onto the transfer tube; a reaction cylinder is rotatably mounted on the negative pressure cylinder at one end and rotatably mounted on the flared end of the converging cone at the other end, with its inner hole being funnel-shaped; an air pipe is fixedly inserted into the reaction cylinder; an inner spiral plate is fixed to the inner wall of the reaction cylinder, with its end near the transfer tube extending into the negative pressure cylinder and slidably connected to it; an outer spiral plate is fixed to the end of the reaction cylinder near the converging cone; a support is rotatably fitted onto the reaction cylinder; a drive motor is fixed to the support; a drive shaft is fixed to the drive motor and rotatably mounted on the support; a drive gear ring is fixed to the end of the reaction cylinder near the negative pressure cylinder; a drive gear is fixed to the drive shaft and meshes with the drive gear ring; and a fan shroud is fixed to the support, located at the outer spiral plate, and rotatably fitted onto the reaction cylinder. The return chute is located on the negative pressure cylinder; the return box is fixed inside the return chute; and the return cylinder is fixed below the return box.

[0005] Furthermore, the reaction element also includes: The air distribution duct is fixed to the end of the air hood closest to the negative pressure cylinder; the air distribution ring duct is fixed to the end of the air distribution duct furthest from the air hood; the external air duct is fixed to the air distribution ring duct; and the heat dissipation trough is located on the end of the air hood furthest from the air distribution duct.

[0006] Furthermore, the reaction element also includes: A first sealing groove is formed on the negative pressure cylinder; a second sealing groove is formed on the reaction cylinder; a first sealing slip ring is fixed on the reaction cylinder and slidably disposed within the first sealing groove; a second sealing slip ring is fixed on the negative pressure cylinder and slidably disposed within the second sealing groove; a sealing groove is formed on the negative pressure cylinder; a sealing rubber ring is nested within the sealing groove; a mating groove is formed on the negative pressure cylinder; a flange is fixed on the reaction cylinder and slidably disposed within the mating groove.

[0007] Furthermore, the recyclable component also includes: The recycling motor is fixed on the recycling box; the spiral blades are rotatably installed inside the recycling cylinder; the bevel gear set has the input bevel gear fixed on the recycling motor and the output bevel gear fixed on the rotating shaft of the spiral blades.

[0008] Furthermore, a support frame is fixedly installed below the cyclone separator.

[0009] The second method is a staged production method for direct zinc oxide using a tunnel kiln, the steps of which are as follows: S1. The zinc ingot raw material is fed from the feeding pipe into the preheating area at the front of the kiln through the feeding system, so that the zinc ingot completes the initial heating pretreatment and then gradually moves to the heating area at the rear of the kiln. S2. Heat the preheating and heating zones through the gas supply system, so that the zinc blocks entering the heating zone melt and vaporize at high temperature to generate zinc vapor, and discharge the solid waste residue from the tail end of the kiln. S3. Start the centrifugal fan to draw high-temperature zinc vapor from the kiln through the steam pipe and transfer pipe to form a directional airflow, so that the zinc vapor airflow enters the negative pressure cylinder and the reaction cylinder. At the same time, the negative pressure is used to introduce air into the reaction cylinder through the air pipe, so that the zinc vapor mixes with the air. S4. Start the drive motor to rotate the reaction cylinder, so that zinc vapor and air undergo an oxidation reaction in the reaction cylinder to generate zinc oxide particles and powder; use the gradually expanding structure of the inner hole of the reaction cylinder to reduce the airflow velocity, so that the large-diameter zinc oxide particles settle down and are intercepted and pushed into the return box by the inner spiral plate, and the zinc oxide powder enters the converging cone with the airflow. S5. Cooling airflow is delivered to the outer spiral plate area outside the reaction cylinder through the blower cooling system. The outer spiral plate rotates synchronously with the reaction cylinder to enhance heat dissipation and cool the inside of the reaction cylinder to control the oxidation reaction temperature. S6. Start the recycling motor to drive the spiral blades in the return cylinder to rotate, and transport the large-diameter zinc oxide particles in the return box back to the feeding system through the waste residue return system so that they can be put back into the kiln to participate in the smelting reaction. S7. The zinc oxide powder that enters the converging cone with the airflow is accelerated and pressurized by the converging cone and then sent to the cyclone separator. The finished zinc oxide powder is separated and collected by the cyclone separator.

[0010] Furthermore, the method steps for step S2 are as follows: S21. The preheating area is heated in a gradient manner using a gas supply system, so that the zinc block is gradually preheated to near the melting temperature during the movement. S22. The preheated zinc block is brought into the heating zone and fully heated, melted and vaporized within a constant high temperature range to stably and continuously generate zinc vapor. S23. Solid waste residue and impurities generated during the smelting process are uniformly discharged from the fixed slag discharge position at the tail end of the kiln, so as to realize the separate output of zinc vapor and waste residue.

[0011] Furthermore, the method steps for step S3 are as follows: S31. Start the centrifugal fan to generate continuous suction force, so that the high temperature zinc vapor forms a stable directional airflow along the steam pipe and transfer pipe, and flows through the negative pressure cylinder into the reaction cylinder in sequence. S32. When the zinc vapor stream passes through the negative pressure cylinder at high speed, a negative pressure environment is formed inside the negative pressure cylinder. The negative pressure force is used to actively draw in ambient temperature air through the air pipe. An air filter is installed at the air inlet end of the air pipe to filter out impurities. The drawn air and the zinc vapor stream are fully mixed inside the reaction cylinder.

[0012] Furthermore, the method steps for step S4 are as follows: S41. Start the drive motor, drive the drive gear to rotate through the drive shaft, and drive the reaction cylinder to rotate at a constant speed at the upper limit of the support through the meshing transmission of the drive gear and the drive gear ring. S42. The mixed airflow of zinc vapor and air undergoes an oxidation reaction in the reaction cylinder, generating zinc oxide particles and powder of different sizes in real time. When the mixed airflow passes through the funnel-shaped gradually expanding section of the inner hole of the reaction cylinder, the flow velocity gradually decreases, and the large-diameter zinc oxide particles settle to the inner wall of the reaction cylinder under the action of gravity. S43. The rotation of the reaction cylinder drives the inner spiral plate to rotate synchronously. The spiral guide of the inner spiral plate continuously pushes the settled large-diameter zinc oxide particles into the return box in the negative pressure cylinder, while the zinc oxide powder continues to flow with the airflow into the tapered cone.

[0013] Furthermore, the method steps of step S5 are as follows: S51. The low-temperature cooling airflow generated by the blower cooling system is preferentially delivered to the external air duct, and then evenly distributed to the inside of the air hood through the air distribution ring pipe and the air distribution pipe in sequence. S52. The cooling airflow inside the shroud is directed to cover and flow through the rotating outer spiral plate area. The contact part between the outer spiral plate and the reaction cylinder is made of a high thermal conductivity metal material. Through the combined effect of forced convection and centrifugal cooling, the mixed reaction area of ​​zinc vapor and air inside the reaction cylinder is continuously and precisely cooled to keep the oxidation reaction temperature stable.

[0014] The above-described solution of the present invention has at least the following beneficial effects: This invention employs a kiln heating and zoned temperature control structure design. Through a gradient temperature zone layout between the preheating and heating zones, it achieves a segmented processing mode where zinc blocks undergo gradual low-temperature preheating and activation before entering the high-temperature heating zone for concentrated melting and vaporization. The integrated rotary reaction cylinder design, combined with a unique trumpet-shaped, gradually expanding inner bore, allows the zinc vapor and air mixing reaction airflow to achieve natural gradient deceleration during directional flow, eliminating the need for additional independent deceleration and settling equipment. Large-diameter zinc oxide particles generated by the oxidation reaction can quickly settle and be separated by gravity. The settled large particles are continuously and directionally pushed into the return box by a synchronously rotating inner spiral plate for collection, while fine, qualified zinc oxide powder is continuously transported with the mixed airflow to the downstream separation process. This truly achieves simultaneous oxidation synthesis reaction and automatic particle classification within a single reaction cylinder, significantly simplifying the overall production process and reducing the need for auxiliary production equipment. The deployment of equipment effectively reduces infrastructure investment and daily maintenance costs. Furthermore, an external spiral plate is installed outside the reaction cylinder, linked to the hood, distribution duct, distribution ring duct, and external duct to form a dedicated integrated cooling airflow distribution and control system. During operation, the external spiral plate rotates synchronously with the reaction cylinder, continuously agitating the surrounding air to create centrifugal turbulent airflow. This airflow, combined with the forced cooling air supplied by the system, forms a composite convective heat exchange effect, significantly improving heat exchange and dissipation efficiency. Real-time dynamic and precise control of the oxidation reaction temperature inside the reaction cylinder is possible, avoiding product quality deviations caused by overheating or uneven temperature, ensuring uniform and stable quality of the finished zinc oxide product. Finally, a dedicated recycling system, consisting of a return box, return cylinder, recycling motor, spiral blades, and bevel gear assembly, allows large-diameter, substandard zinc oxide particles, after grading and sorting, to be mechanically and forcibly transported back to the front-end feeding system via the waste recycling system, and then reintroduced into the kiln for secondary smelting and processing. Attached Figure Description

[0015] Figure 1 This is a front view of an overall structure of a tunnel kiln for the graded production of direct zinc oxide, provided in an embodiment of the present invention. Figure 2 This is a schematic diagram of the negative pressure cylinder structure of a tunnel kiln for the graded production of direct zinc oxide, provided in an embodiment of the present invention. Figure 3 This invention provides an embodiment of a tunnel kiln for the graded production of direct zinc oxide. Figure 2 Enlarged view of point A; Figure 4 This invention provides a schematic diagram of the air pipe structure for a tunnel kiln used in the staged production of direct zinc oxide. Figure 5 This is a schematic diagram of the reaction cylinder structure of a tunnel kiln for the staged production of direct zinc oxide, provided in an embodiment of the present invention. Figure 6 This invention provides an embodiment of a tunnel kiln for the graded production of direct zinc oxide. Figure 5 Enlarged view of point B; Figure 7 This invention provides an embodiment of a tunnel kiln for the graded production of direct zinc oxide. Figure 5 Enlarged view of point C; Figure 8 This invention provides an embodiment of a tunnel kiln for the graded production of direct zinc oxide. Figure 5 Enlarged view of point D; Figure 9 This invention provides an embodiment of a tunnel kiln for the graded production of direct zinc oxide. Figure 5 Enlarged view of point E; Figure 10 This is a process flow diagram of a tunnel kiln-based graded production method for direct zinc oxide, provided as an embodiment of the present invention.

[0016] Explanation of reference numerals in the attached figures: In the diagram: 1. Kiln; 101. Preheating zone; 102. Heating zone; 2. Controller; 3. Feeding pipe; 4. Steam pipe; 5. Transfer pipe; 6. Centrifugal fan; 7. Reactor; 701. Negative pressure cylinder; 702. Reactor cylinder; 703. Air pipe; 704. Inner spiral plate; 705. Outer spiral plate; 706. Support; 707. Drive motor; 708. Drive shaft; 709. Drive gear ring; 7010. Drive gear; 7011. Air hood; 7012. Air distribution pipe; 7013. Air distribution ring pipe; 701 4. External air duct; 7015. Heat dissipation groove; 7016. First sealing groove; 7017. Second sealing groove; 7018. First sealing slip ring; 7019. Second sealing slip ring; 7020. Sealing groove; 7021. Sealing rubber ring; 7022. Butt joint groove; 7023. Flange; 8. Recycling components; 801. Return material chute; 802. Return material box; 803. Return material cylinder; 804. Recycling motor; 805. Spiral blade; 806. Bevel gear set; 9. Gradient conical cylinder; 10. Cyclone separator; 11. Support frame. Detailed Implementation

[0017] Exemplary embodiments of the invention will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the invention are shown in the drawings, it should be understood that the invention may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this invention will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

[0018] like Figures 1 to 10As shown, an embodiment of the present invention provides a tunnel kiln for the graded production of direct zinc oxide, comprising: a kiln 1, the kiln 1 being equipped with a gas supply system, a feeding system, a blower cooling system and a waste residue recycling system.

[0019] It also includes: a controller 2, fixed to the front end of the kiln 1; a feeding pipe 3, fixed to the front end of the kiln 1; a steam pipe 4, fixed to the rear end of the kiln 1; a transfer pipe 5, fixed to the steam pipe 4; a centrifugal fan 6, with its base fixed to the kiln 1 and its working end fixed to the transfer pipe 5; a reaction element 7, fixed to the end of the transfer pipe 5 away from the kiln 1; a recovery element 8, fixed to the reaction element 7; a tapered cone 9, with its flared end rotatably mounted on the reaction element 7; a cyclone separator 10, fixed to the tapered end of the tapered cone 9; a preheating zone 101, located at the front end of the kiln 1; a heating zone 102, located at the rear end of the kiln 1; and a support frame 11 fixedly mounted below the cyclone separator 10.

[0020] Specifically, the kiln 1 achieves gradient heating and centralized vaporization of zinc ingot raw materials through the partitioned design of the preheating zone 101 and the heating zone 102. Together with the downstream reaction unit 7, the tapered cone 9 and the cyclone separator 10, it forms a continuous production line from smelting vaporization to oxidation reaction and then to powder classification and collection. The controller 2 uniformly regulates the operating parameters of each system, the centrifugal fan 6 provides the power for zinc vapor transportation, and the support frame 11 provides stable support for the cyclone separator 10, ensuring the continuity and stability of the overall equipment operation.

[0021] In another preferred embodiment of the present invention, the reaction element 7 includes: a negative pressure cylinder 701, sleeved on the transfer tube 5; a reaction cylinder 702, one end rotatably disposed on the negative pressure cylinder 701, and the other end rotatably disposed on the flared end of the tapered conical cylinder 9; an air pipe 703, fixedly inserted into the reaction cylinder 702; an inner spiral plate 704, fixed on the inner wall of the reaction cylinder 702, with one end near the transfer tube 5 extending into the negative pressure cylinder 701 and slidably connected to the negative pressure cylinder 701; and an outer spiral plate 705, fixed on the reaction cylinder 702 near the tapered conical cylinder 9. One end is supported by: a support 706, rotatably sleeved on the reaction cylinder 702; a drive motor 707, fixed on the support 706; a drive shaft 708, fixed on the drive motor 707 and rotatably mounted on the support 706; a drive gear ring 709, fixed on one end of the reaction cylinder 702 near the negative pressure cylinder 701; a drive gear 7010, fixed on the drive shaft 708 and meshing with the drive gear ring 709; and a fan shroud 7011, fixed on the support 706, located at the outer spiral plate 705, and rotatably sleeved on the reaction cylinder 702.

[0022] The reaction component 7 further includes: a distribution duct 7012, fixed to the end of the hood 7011 near the negative pressure cylinder 701; a distribution ring duct 7013, fixed to the end of the distribution duct 7012 away from the hood 7011; an external duct 7014, fixed to the distribution ring duct 7013; a heat dissipation groove 7015, formed on the end of the hood 7011 away from the distribution duct 7012; a first sealing groove 7016, formed on the negative pressure cylinder 701; a second sealing groove 7017, formed on the reaction cylinder 702; and a first sealing... A sealing slip ring 7018 is fixed on the reaction cylinder 702 and slidably disposed within the first sealing slip groove 7016; a second sealing slip ring 7019 is fixed on the negative pressure cylinder 701 and slidably disposed within the second sealing slip groove 7017; a sealing groove 7020 is formed on the negative pressure cylinder 701; a sealing rubber ring 7021 is nested within the sealing groove 7020; a docking groove 7022 is formed on the negative pressure cylinder 701; and a flange 7023 is fixed on the reaction cylinder 702 and slidably disposed within the docking groove 7022.

[0023] Specifically, the reaction unit 7 is centered around the rotating reaction cylinder 702. Utilizing the funnel-shaped, gradually expanding structure of its inner bore, it naturally decelerates the airflow mixing zinc vapor and air, causing large-diameter particles generated by the oxidation reaction to settle under gravity and be pushed towards the negative pressure cylinder 701 by the rotating inner spiral plate 704. Simultaneously, the outer spiral plate 705 generates centrifugal airflow as the reaction cylinder 702 rotates, which, in conjunction with the cooling airflow introduced through the air distribution pipe 7012, air distribution ring pipe 7013, and outer air pipe 7014, enhances the heat dissipation efficiency of the reaction cylinder 702, achieving precise control of the oxidation reaction temperature. The multiple sealing structures of the first sealing slip ring 7018, the second sealing slip ring 7019, and the sealing rubber ring 7021 ensure the airtightness of the rotating connection, preventing zinc vapor leakage.

[0024] In another preferred embodiment of the present invention, the recycling component 8 includes: a recycling trough 801, which is formed on the negative pressure cylinder 701; a recycling box 802, which is fixed inside the recycling trough 801; a recycling cylinder 803, which is fixed below the recycling box 802; a recycling motor 804, which is fixed on the recycling box 802; a spiral blade 805, which is rotatably disposed inside the recycling cylinder 803; and a bevel gear set 806, with the input bevel gear fixed on the recycling motor 804 and the output bevel gear fixed on the rotating shaft of the spiral blade 805.

[0025] Specifically, the recycling unit 8 is used to receive large-diameter zinc oxide particles pushed to the return box 802 by the inner spiral plate 704. The spiral blades 805 are driven to rotate by the recycling motor 804 through the bevel gear set 806, and the material is stably transported along the return cylinder 803 to the waste residue return system, realizing the online recycling and recycling of large-diameter materials and improving the comprehensive utilization rate of zinc resources.

[0026] Working principle: The feeding pipe 3 connects to the matching feeding system, continuously supplying raw materials to the kiln 1 for production operations; the gas supply system is installed at the bottom of the kiln 1, continuously providing a stable heat source for the preheating zone 101 and the heating zone 102 inside the kiln 1; the forced-air cooling system connects to the external air duct 7014, continuously supplying cooling airflow to the outside of the reaction cylinder 702, achieving efficient cooling and heat dissipation during the operation of the reaction cylinder 702; the waste residue recycling system is installed at the bottom port of the recycling cylinder 803, allowing large-diameter zinc oxide particles separated during the equipment's production process to flow back to the feeding system through the waste residue recycling system. The material is fed back into the kiln 1 through the feeding pipe 3 to participate in repeated smelting and reaction processing. The staff can use the controller 2 to uniformly control and adjust the operating parameters of the gas supply system, feeding system, blower cooling system, and waste residue return system, and simultaneously control the start-up, shutdown, operation, and working power of the centrifugal fan 6, drive motor 707, and recovery motor 804. The overall length of the reaction cylinder 702 can be flexibly customized according to the actual zinc oxide production and processing specifications and capacity requirements. The overall installation length of the inner spiral plate 704 and the outer spiral plate 705 is synchronously extended or shortened according to the size of the reaction cylinder 702 to ensure that the material conveying and heat dissipation operations are matched and adapted.

[0027] The zinc ingot raw material is conveyed under stable pressure through the feeding system and fed into the preheating zone 101 at the front end of the kiln 1 through the feeding pipe 3. After the zinc ingot completes the initial heating pretreatment in the preheating zone 101, it gradually moves slowly to the heating zone 102 at the rear end of the kiln 1. The gas supply system at the bottom of the kiln 1 continuously burns and heats the zinc ingot inside the preheating zone 101 in a gradient preheating process. The zinc ingot entering the heating zone 102 is fully heated and melted and vaporized in a high-temperature environment, stably generating zinc vapor. The solid waste slag and impurities generated during smelting and processing are uniformly discharged from the fixed slag discharge position at the rear end of the kiln 1, completing the initial smelting and vaporization process of the raw material.

[0028] During equipment operation, centrifugal fan 6 is started, and centrifugal fan 6 continuously runs to generate suction force. Through the cooperation of steam pipe 4 and transfer pipe 5, it draws high-temperature zinc vapor generated inside kiln 1 to form a directional airflow. The zinc vapor airflow first enters the negative pressure cylinder 701 through the internal channel of transfer pipe 5, and then continues to flow directionally into the reaction cylinder 702. During the high-speed flow of zinc vapor airflow, a negative pressure environment is automatically formed inside the negative pressure cylinder 701. The negative pressure force actively draws in ambient temperature air through air pipe 703. The air inlet end of air pipe 703 is equipped with an air filter component, which can effectively filter impurities and dust in the outside air, and prevent impurities from entering the reaction process and affecting the purity of the zinc oxide product. Air pipe 703 can also be directly connected to the blower cooling system, which continuously delivers directional airflow. The zinc vapor airflow and the airflow are fully mixed and contacted inside the reaction cylinder 702. The zinc vapor and oxygen undergo an oxidation chemical reaction, generating zinc oxide particles and zinc oxide powder of different particle sizes in real time.

[0029] When the equipment is in staged reaction operation, the drive motor 707 is started. The drive motor 707 drives the drive shaft 708 to rotate synchronously. The rotating drive shaft 708 drives the drive gear 7010 to rotate synchronously. The drive gear 7010 meshes with the drive gear ring 709, which in turn drives the drive gear ring 709 and the reaction cylinder 702 to rotate synchronously as a whole. The reaction cylinder 702 is stably sleeved on the support 706 and rotates at a uniform speed under the support and limit of the support 706 throughout the process, providing continuous rotational power for internal material conveying, particle interception and external heat dissipation.

[0030] The zinc vapor and air oxidation reaction is completed entirely inside the reaction cylinder 702. The end of the reaction cylinder 702 facing the tapered cone 9 adopts a funnel-shaped structure design, and the inner diameter of the reaction cylinder 702 gradually increases along the material flow direction. The flow velocity of the zinc vapor and air mixture gradually decreases during the flow process. The zinc oxide particles generated by the oxidation reaction detach from the suspended state of the mixed air after the air flow velocity decreases and settle to the inner wall of the reaction cylinder 702 by their own gravity. The settled zinc oxide particles are effectively intercepted by the inner spiral plate 704 fixed to the inner wall of the reaction cylinder 702. The continuous rotation of the reaction cylinder 702 drives the inner spiral plate 704 to rotate synchronously. The spiral structure of the inner spiral plate 704 guides the rotation of the reaction cylinder 702. The generated pushing force continuously and smoothly pushes the large-diameter zinc oxide particles towards the negative pressure cylinder 701; one end of the inner spiral plate 704 extends into the interior of the negative pressure cylinder 701 and maintains a sliding fit, continuously pushing the large-diameter zinc oxide particles into the interior of the negative pressure cylinder 701, and finally falling into the return box 802 of the negative pressure cylinder 701; the zinc oxide powder follows the continuous flow of the mixed airflow and smoothly enters the converging cone 9 from the tail end of the reaction cylinder 702. The converging cone 9's narrowing structure accelerates and pressurizes the mixed airflow, and the accelerated mixed airflow is directly sent into the cyclone separator 10. The cyclone separator 10 separates the zinc oxide powder from the mixed airflow through centrifugal separation, completing the collection and recovery of high-quality finished zinc oxide powder.

[0031] During the continuous rotation of the reaction cylinder 702, the outer spiral plate 705 mounted on the outside is rotated synchronously. The contact parts between the reaction cylinder 702 and the outer spiral plate 705 are made of high thermal conductivity metal. During the rotation, the reaction cylinder 702 and the outer spiral plate 705 are in full contact with the outside air, achieving self-heating and cooling through heat conduction and heat exchange. After the blower cooling system is started simultaneously, the low-temperature cooling airflow generated by the blower cooling system is preferentially delivered to the inside of the outer air duct 7014. The cooling airflow enters the air distribution ring pipe 7013 and the air distribution pipe 7012 in sequence along the outer air duct 7014, and is finally evenly delivered into the inside of the air hood 7011 through the air distribution pipe 7012, directionally covering the working area of ​​the outer spiral plate 705. In conjunction with the rotating outer spiral plate 705, the heat exchange efficiency is enhanced, and the zinc vapor and air mixing reaction area inside the reaction cylinder 702 is continuously and precisely cooled to ensure that the oxidation reaction temperature is stable and controllable. The low-temperature cooling airflow in the air hood 7011 is discharged from the heat dissipation slot 7015.

[0032] When zinc oxide particles enter the return box 802, the recovery motor 804 is started. The recovery motor 804 drives the rotation of the bevel gear set 806, which in turn drives the spiral blades 805 in the return cylinder 803 to rotate. The rotation of the spiral blades 805 pushes the zinc oxide particles back to the waste residue return system, and then transfers them to the feeding system through the waste residue return system. They can then re-enter the feeding pipe 3 and the kiln 1.

[0033] Embodiments of the present invention provide a method for the staged production of direct zinc oxide using a tunnel kiln, the method steps of which are as follows: S1. The zinc block raw material is fed from the feeding pipe 3 into the preheating area 101 at the front end of the kiln 1 through the feeding system, so that the zinc block completes the initial heating pretreatment and then gradually moves to the heating area 102 at the rear end of the kiln 1. S2. Heat is supplied to the preheating zone 101 and the heating zone 102 through the gas supply system, so that the zinc block entering the heating zone 102 melts and vaporizes to generate zinc vapor in a high-temperature environment, and the solid waste residue is discharged from the tail end of the kiln 1. S3. Start the centrifugal fan 6 to draw high-temperature zinc vapor from the kiln 1 through the steam pipe 4 and the transfer pipe 5 to form a directional airflow, so that the zinc vapor airflow enters the negative pressure cylinder 701 and the reaction cylinder 702. At the same time, the negative pressure is used to introduce air into the reaction cylinder 702 through the air pipe 703, so that the zinc vapor mixes with the air. S4. Start the drive motor 707 to drive the reaction cylinder 702 to rotate, so that zinc vapor and air undergo an oxidation reaction in the reaction cylinder 702 to generate zinc oxide particles and powder; use the gradually expanding structure of the inner hole of the reaction cylinder 702 to reduce the airflow velocity, so that the large-diameter zinc oxide particles settle down and are intercepted and pushed into the return box 802 by the inner spiral plate 704, and the zinc oxide powder enters the tapered cone 9 with the airflow; S5. Cooling airflow is delivered to the outer spiral plate 705 area outside the reaction cylinder 702 through the blower cooling system. The outer spiral plate 705 rotates synchronously with the reaction cylinder 702 to enhance heat dissipation and cool the inside of the reaction cylinder 702 to control the oxidation reaction temperature. S6. Start the recycling motor 804 to drive the spiral blades 805 in the return cylinder 803 to rotate, and transport the large-diameter zinc oxide particles in the return box 802 back to the feeding system through the waste residue return system so that they can be put back into the kiln 1 to participate in the smelting reaction. S7. The zinc oxide powder that enters the converging cone 9 with the airflow is accelerated and pressurized by the converging cone 9 and then sent to the cyclone separator 10. The finished zinc oxide powder is separated and collected by the cyclone separator 10.

[0034] The steps for step S2 are as follows: S21. The preheating zone 101 is heated in a gradient manner using a gas supply system, so that the zinc block is gradually preheated to near the melting temperature during the movement. S22. The preheated zinc block is brought into the heating zone 102, where it is fully heated, melted, and vaporized in a constant high-temperature range to stably and continuously generate zinc vapor. S23. Solid waste residue and impurities generated during the smelting process are uniformly discharged from the fixed slag discharge position at the tail end of kiln 1, so as to realize the separate output of zinc vapor and waste residue.

[0035] The steps for step S3 are as follows: S31. Start the centrifugal fan 6 to generate continuous suction force, so that the high temperature zinc vapor forms a stable directional airflow along the steam pipe 4 and the transfer pipe 5, and flows through the negative pressure cylinder 701 and enters the reaction cylinder 702 in sequence. S32. When the zinc vapor gas flows through the negative pressure cylinder 701 at high speed, a negative pressure environment is formed inside the negative pressure cylinder 701. The negative pressure force is used to actively draw in ambient temperature air through the air pipe 703. An air filter component is installed at the air inlet end of the air pipe 703 to filter out impurities. The drawn air and the zinc vapor gas flow are fully mixed inside the reaction cylinder 702.

[0036] The steps for step S4 are as follows: S41. Start the drive motor 707, drive the drive gear 7010 to rotate through the drive shaft 708, and drive the reaction cylinder 702 to rotate at a constant speed at the upper limit of the support 706 through the meshing transmission of the drive gear 7010 and the drive gear ring 709. S42. The mixed airflow of zinc vapor and air undergoes an oxidation reaction in the reaction cylinder 702, generating zinc oxide particles and powder of different sizes in real time. When the mixed airflow passes through the funnel-shaped gradually expanding section of the inner hole of the reaction cylinder 702, the flow velocity gradually decreases, and the large-diameter zinc oxide particles settle to the inner wall of the reaction cylinder 702 under the action of gravity. S43. The rotation of the reaction cylinder 702 drives the inner spiral plate 704 to rotate synchronously. The spiral guide of the inner spiral plate 704 continuously pushes the settled large-diameter zinc oxide particles into the return box 802 in the negative pressure cylinder 701, while the zinc oxide powder continues to flow with the airflow into the tapered cone 9.

[0037] The steps for step S5 are as follows: S51. The low-temperature cooling airflow generated by the blower cooling system is preferentially delivered to the external air duct 7014, and then evenly distributed to the inside of the air hood 7011 through the air distribution ring pipe 7013 and the air distribution pipe 7012 in sequence. S52, directs the cooling airflow in the shroud 7011 to cover and flow through the area of ​​the rotating outer spiral plate 705. The contact part between the outer spiral plate 705 and the reaction cylinder 702 is made of a high thermal conductivity metal material. Through the combined effect of forced convection and rotational centrifugal heat dissipation, the mixed reaction area of ​​zinc vapor and air inside the reaction cylinder 702 is continuously and precisely cooled to keep the oxidation reaction temperature stable.

[0038] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A tunnel kiln-type equipment for the staged production of direct zinc oxide, comprising: The kiln, equipped with a gas supply system, a material feeding system, a forced-air cooling system, and a waste residue recycling system, is characterized in that it further includes: The controller is fixed at the front end of the kiln; the feeding pipe is fixed at the front end of the kiln; the steam pipe is fixed at the rear end of the kiln; the transfer pipe is fixed on the steam pipe; the centrifugal fan has its base fixed on the kiln and its working end fixed on the transfer pipe; the reaction vessel is fixed on the end of the transfer pipe away from the kiln; the recovery vessel is fixed on the reaction vessel; the converging cone has its flared end rotatably mounted on the reaction vessel; and the cyclone separator is fixed on the converging end of the converging cone. The preheating zone is located at the front end of the kiln; the heating zone is located at the rear end of the kiln. A negative pressure cylinder is fitted onto the transfer tube; a reaction cylinder is rotatably mounted on the negative pressure cylinder at one end and rotatably mounted on the flared end of the converging cone at the other end, with its inner hole being funnel-shaped; an air pipe is fixedly inserted into the reaction cylinder; an inner spiral plate is fixed to the inner wall of the reaction cylinder, with its end near the transfer tube extending into the negative pressure cylinder and slidably connected to it; an outer spiral plate is fixed to the end of the reaction cylinder near the converging cone; a support is rotatably fitted onto the reaction cylinder; a drive motor is fixed to the support; a drive shaft is fixed to the drive motor and rotatably mounted on the support; a drive gear ring is fixed to the end of the reaction cylinder near the negative pressure cylinder; a drive gear is fixed to the drive shaft and meshes with the drive gear ring; and a fan shroud is fixed to the support, located at the outer spiral plate, and rotatably fitted onto the reaction cylinder. The return chute is located on the negative pressure cylinder; the return box is fixed inside the return chute; and the return cylinder is fixed below the return box.

2. The equipment for graded production of direct zinc oxide in a tunnel kiln according to claim 1, characterized in that, The reaction element further includes: The air distribution duct is fixed to the end of the air hood closest to the negative pressure cylinder; the air distribution ring duct is fixed to the end of the air distribution duct furthest from the air hood; the external air duct is fixed to the air distribution ring duct; and the heat dissipation trough is located on the end of the air hood furthest from the air distribution duct.

3. The equipment for graded production of direct zinc oxide in a tunnel kiln according to claim 2, characterized in that, The reaction element further includes: A first sealing groove is formed on the negative pressure cylinder; a second sealing groove is formed on the reaction cylinder; a first sealing slip ring is fixed on the reaction cylinder and slidably disposed within the first sealing groove; a second sealing slip ring is fixed on the negative pressure cylinder and slidably disposed within the second sealing groove; a sealing groove is formed on the negative pressure cylinder; a sealing rubber ring is nested within the sealing groove; a mating groove is formed on the negative pressure cylinder; a flange is fixed on the reaction cylinder and slidably disposed within the mating groove.

4. The equipment for graded production of direct zinc oxide in a tunnel kiln according to claim 1, characterized in that, The recycled components also include: The recycling motor is fixed on the recycling box; the spiral blades are rotatably installed inside the recycling cylinder; the bevel gear set has the input bevel gear fixed on the recycling motor and the output bevel gear fixed on the rotating shaft of the spiral blades.

5. The equipment for staged production of direct zinc oxide in a tunnel kiln according to claim 1, characterized in that, A support frame is fixedly installed below the cyclone separator.

6. A method for graded production of direct zinc oxide in a tunnel kiln, applied to the equipment for graded production of direct zinc oxide in a tunnel kiln as described in any one of claims 1-5, characterized in that, The steps are as follows: S1. The zinc ingot raw material is fed from the feeding pipe into the preheating area at the front of the kiln through the feeding system, so that the zinc ingot completes the initial heating pretreatment and then gradually moves to the heating area at the rear of the kiln. S2. Heat the preheating and heating zones through the gas supply system, so that the zinc blocks entering the heating zone melt and vaporize at high temperature to generate zinc vapor, and discharge the solid waste residue from the tail end of the kiln. S3. Start the centrifugal fan to draw high-temperature zinc vapor from the kiln through the steam pipe and transfer pipe to form a directional airflow, so that the zinc vapor airflow enters the negative pressure cylinder and the reaction cylinder. At the same time, the negative pressure is used to introduce air into the reaction cylinder through the air pipe, so that the zinc vapor mixes with the air. S4. Start the drive motor to rotate the reaction cylinder, so that zinc vapor and air undergo an oxidation reaction in the reaction cylinder to generate zinc oxide particles and powder; use the gradually expanding structure of the inner hole of the reaction cylinder to reduce the airflow velocity, so that the large-diameter zinc oxide particles settle down and are intercepted and pushed into the return box by the inner spiral plate, and the zinc oxide powder enters the converging cone with the airflow. S5. Cooling airflow is delivered to the outer spiral plate area outside the reaction cylinder through the blower cooling system. The outer spiral plate rotates synchronously with the reaction cylinder to enhance heat dissipation and cool the inside of the reaction cylinder to control the oxidation reaction temperature. S6. Start the recycling motor to drive the spiral blades in the return cylinder to rotate, and transport the large-diameter zinc oxide particles in the return box back to the feeding system through the waste residue return system so that they can be put back into the kiln to participate in the smelting reaction. S7. The zinc oxide powder that enters the converging cone with the airflow is accelerated and pressurized by the converging cone and then sent to the cyclone separator. The finished zinc oxide powder is separated and collected by the cyclone separator.

7. The method for graded production of direct zinc oxide in a tunnel kiln according to claim 6, characterized in that, The steps for step S2 are as follows: S21. The preheating area is heated in a gradient manner using a gas supply system, so that the zinc block is gradually preheated to near the melting temperature during the movement. S22. The preheated zinc block is brought into the heating zone and fully heated, melted and vaporized within a constant high temperature range to stably and continuously generate zinc vapor. S23. Solid waste residue and impurities generated during the smelting process are uniformly discharged from the fixed slag discharge position at the tail end of the kiln, so as to realize the separate output of zinc vapor and waste residue.

8. A method for graded production of direct zinc oxide in a tunnel kiln according to claim 6, characterized in that, The steps for step S3 are as follows: S31. Start the centrifugal fan to generate continuous suction force, so that the high temperature zinc vapor forms a stable directional airflow along the steam pipe and transfer pipe, and flows through the negative pressure cylinder into the reaction cylinder in sequence. S32. When the zinc vapor stream passes through the negative pressure cylinder at high speed, a negative pressure environment is formed inside the negative pressure cylinder. The negative pressure force is used to actively draw in ambient temperature air through the air pipe. An air filter is installed at the air inlet end of the air pipe to filter out impurities. The drawn air and the zinc vapor stream are fully mixed inside the reaction cylinder.

9. A method for graded production of direct zinc oxide in a tunnel kiln according to claim 6, characterized in that, The steps for step S4 are as follows: S41. Start the drive motor, drive the drive gear to rotate through the drive shaft, and drive the reaction cylinder to rotate at a constant speed at the upper limit of the support through the meshing transmission of the drive gear and the drive gear ring. S42. The mixed airflow of zinc vapor and air undergoes an oxidation reaction in the reaction cylinder, generating zinc oxide particles and powder of different sizes in real time. When the mixed airflow passes through the funnel-shaped gradually expanding section of the inner hole of the reaction cylinder, the flow velocity gradually decreases, and the large-diameter zinc oxide particles settle to the inner wall of the reaction cylinder under the action of gravity. S43. The rotation of the reaction cylinder drives the inner spiral plate to rotate synchronously. The spiral guide of the inner spiral plate continuously pushes the settled large-diameter zinc oxide particles into the return box in the negative pressure cylinder, while the zinc oxide powder continues to flow with the airflow into the tapered cone.

10. A method for graded production of direct zinc oxide in a tunnel kiln according to claim 6, characterized in that, The steps for step S5 are as follows: S51. The low-temperature cooling airflow generated by the blower cooling system is preferentially delivered to the external air duct, and then evenly distributed to the inside of the air hood through the air distribution ring pipe and the air distribution pipe in sequence. S52. The cooling airflow inside the shroud is directed to cover and flow through the rotating outer spiral plate area. The contact part between the outer spiral plate and the reaction cylinder is made of a high thermal conductivity metal material. Through the combined effect of forced convection and centrifugal cooling, the mixed reaction area of ​​zinc vapor and air inside the reaction cylinder is continuously and precisely cooled to keep the oxidation reaction temperature stable.

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