NL2029925B1

NL2029925B1 - Horizontal high-temperature ball milling device

Info

Publication number: NL2029925B1
Application number: NL2029925A
Authority: NL
Inventors: Lin Xiaochen; Zhang Houhu; Ma Bing; Zhao Zehua; Xu Yuanshun
Original assignee: Nanjing Institute Of Environmental Sciences Mini Of Ecology And Environment Of The Peoples Republic
Priority date: 2021-11-26
Filing date: 2021-11-26
Publication date: 2023-06-16

Abstract

A horizontal high-temperature ball milling device is provided, which includes a supporting system, a driving transmission system and a heating ball milling system. The heating ball milling system includes a cylinder body and metal grinding balls. The cylinder body is transversely arranged. A multi-layer structure is laid in a cylinder wall of the cylinder body and includes a wear-resistant layer, a thermal insulation layer and a magnet yoke coil layer. The wear-resistant layer is located on an innermost side of the multi-layer structure. The thermal insulation layer is located on an outer side of the wear-resistant layer. The magnet yoke coil layer is located on an outer side of the thermal insulation layer or embedded in the outer side of the thermal insulation layer. The magnet yoke coil layer includes a magnet yoke, and a coil located on an inner side of the magnet yoke or embedded in the inner side of the magnet yoke. The metal grinding balls are provided in the cylinder body. The cylinder body is provided on the supporting system. The driving transmission system drives the cylinder body to roll. The metal grinding balls grind the materials in the rolling cylinder body, and the coil is energized to generate an internal alternating magnetic field, to generate induced eddy current on a surface of each metal grinding ball to heat the materials. Ball milling and heat treatment on the materials are simultaneously carried out, and there are the advantages of accurate temperature control, high efficiency, energy conservation.

Description

HORIZONTAL HIGH-TEMPERATURE BALL MILLING DEVICE

TECHNICAL FIELD

[01] The present disclosure belongs to the technical field of powder processing machinery devices, and relates to a ball milling device, in particular to a horizontal high-temperature ball milling device.

BACKGROUND ART

[02] A ball mill is not only a grinding device widely used in traditional industries such as mineral processing, building materials and chemical industry, but also a key device in the field of manufacturing electronic raw materials and nanometer materials.

Generally, steel balls or ceramic balls are used to assist in crushing and grinding of materials. In the process of powder processing, it is often necessary to heat the powder pnor to and subsequent to the grinding process in order to achieve the effects of drying or high-temperature heat treatment. In the prior art, grinding and heating belong to two processes, at least two sets of devices are needed, and the devices occupy a large area.

According to the properties of the processed powder, vacuum environment or gas protection is needed in some processing processes. The transportation and preservation of materials between multiple sets of devices increases the procedures and costs.

Integrating multiple procedures can reduce the costs and improve the quality stability.

In modern material preparation, there is also a method to promote the reaction rate by using the high surface chemical energy at the instant of particle breaking. In order to make the reaction proceed smoothly, temperature control 1s also needed. The material processing method with combining grinding and heat treatment has a good application prospect and economic benefit.

[03] The invention disclosure CN100460074C and CN102614965B adopt the technical route of placing the ball milling device in a high-temperature furnace. In the high temperature, all parts of the ball milling device are easy to be damaged, especially the driving and transmission parts. Moreover, the heating from outside to inside needs to heat the cylinder wall of the ball milling device first, and then the heating is realized through the heat transfer between the cylinder wall and the material. The contact area between the cylinder wall and the materials is limited, thereby resulting in slow temperature rise and uneven heating of the materials. In addition, the technology of placing the ball milling device in the high-temperature furnace can only process materials in batches, and cannot realize continuous production. The invention disclosure CN107866312B and CN109282585B use hot gas to dry materials, which can realize continuous production. However, due to the low specific heat of gas, the energy that can be carried by the gas is limited. It is easy to take away the powder materials in ball milling device by blindly increasing the gas flow rate. In fact, the heating speed of gas is low, and its function is limited to drying, which cannot reach a higher temperature. The application publication No. CN109663639A proposes to use microwave for heating. In theory, materials can be directly heated, and the high-temperature pressure to the cylinder body and related driving and transmission parts is reduced. However, in the prior art, the construction of large-scale microwave devices and the shielding costs of microwave radiation are extremely expensive, which is only suitable for small laboratory instruments and is difficult to be used in production. Moreover, microwave heating can only be used for microwave sensitive matenals, and the machinable materials are limited, which is not universal.

SUMMARY

[04] In view of the problem that the existing high-temperature ball milling technology and device cannot realize large-scale and continuous production of different materials, the present disclosure provides a technology and device for heating metal grinding balls by electromagnetic induction, which utilizes the contact between grinding balls and materials during grinding to continuously heat the target materials efficiently, rapidly and uniformly inside the ball milling cylinder with the closed space.

Thus, high-temperature ball milling scaled continuous production is realized under the control of precise temperature and reaction atmosphere.

[05] In order to achieve the above purpose, the present disclosure provides a horizontal high-temperature ball milling device, including a supporting system, a driving transmission system and a heating ball milling system; where the heating ball milling system includes a cylinder body and multiple metal grinding balls. The cylinder body is transversely arranged, and a left end and a right end of the cylinder body are provided with a feed inlet and a feed outlet respectively. A multi-layer structure is provided in a cylinder wall of the cylinder body and includes a wear-resistant layer, a thermal insulation layer and a magnet yoke coil layer. The wear-resistant layer is located on an innermost side of the multi-layer structure, the thermal insulation layer is located on an outer side of the wear-resistant layer, the magnet yoke coil layer is located on an outer side of the thermal insulation layer or embedded in the outer side of the thermal insulation layer. Embedding the magnet yoke coil layer on the outer side of the thermal insulation layer means that the magnet yoke coil layer is shorter than the thermal insulation layer, and the thermal insulation layer wraps the magnet yoke coil layer on an inner side and left and right sides. The magnet yoke coil layer includes a magnet yoke and a coil, the coil is located on an inner side of the magnet yoke or embedded in the inner side of the magnet yoke, where embedding the coil in the inner side of the magnet yoke means that the coil is fixed in the magnet yoke and located on the inner side relative to the whole magnet yoke. The coil is connected with a high-frequency power supply. The multiple metal grinding balls are provided in the cylinder body. The cylinder body is provided on the supporting system, the driving transmission system drives the cylinder body to roll around a transverse center line of the cylinder body. The cylinder body rolls, and materials and gas enter the cylinder body from the feed inlet, such that the metal grinding balls grinds the materials in the rolling cylinder body, and the coil is energized with high-frequency alternating current to generate an alternating magnetic field inside the cylinder body simultaneously, such that a surface of each of the metal grinding balls generates induced eddy current to heat the materials.

[06] In some embodiments, a material of the wear-resistant layer may has a non-magnetic and non-conductive material to avoid electromagnetic shielding.

[07] In some embodiments, the supporting system may include a base, two brackets and two bearings. The two brackets may be fixed on the base and are oppositely arranged. The two bearings may be provided respectively outside the feed inlet and the feed outlet, and each of the feed inlet and the feed outlet may be installed on a corresponding one of the two brackets through a respective one of the two bearings.

[08] In some embodiments, the driving transmission system may include a motor, a reducer, a transmission gear and a driven gear. The driven gear may be fixedly sleeved outside the cylinder body. The transmission gear may be located on an outer side of the driven gear and meshed with the driven gear. The motor may drive the transmission gear to rotate by the reducer, and the driven gear and the cylinder body may rotate together therewith.

[09] In some embodiments, the device further may include a gas or material in-and-out control system, where the system may include a feed inlet connector, a feed outlet connector, a feed inlet control unit, a feed outlet control unit, a gas inlet valve and a gas outlet valve. The feed inlet connector and the feed outlet connector may be connected and communicated with the feed inlet and the feed outlet of the cylinder body through a corresponding one of the two bearings respectively, and may be unrotatable when the cylinder body rotates. The feed inlet control unit and the feed outlet control unit may be connected with the feed inlet connector and the feed outlet connector respectively, to control the materials in and out. The gas inlet valve and the gas outlet valve may be provided on the feed inlet connector and the feed outlet connector respectively, to control the gas inlet and outlet.

[10] In some embodiments, the two bearings may be airtight bearings.

[11] In some embodiments, the device further may include a non-metallic and non-thermocouple temperature sensors which are provided in the cylinder body to measure a temperature of the material of the cylinder body.

[12] In some embodiments, the feed outlet may be provided with a filter sieve or a filter grille, and specification of the filter holes of the filter sieve or the filter grille may be larger than target product particles and smaller than the metal grinding balls.

[13] In some embodiments, the coil layer may be powered by a high-frequency alternating current power supply. A frequency range of the high-frequency alternating 5 current power supply may be 1000 Hz to 100000 Hz, and a power of the high-frequency alternating current power supply may be adjustable.

[14] In some embodiments, the metal grinding ball may has wear-resistant high chromium steel material at 300 celsius degrees or less, or nickel-based high-temperature alloy material at 300 celsius degrees or more; the wear-resistant layer may has ceramic refractory material at 300 celsius degrees or more. 300 celsius degrees may refer to the working temperature, that may be, the heating temperature after the coil is energized.

[15] The embodiments have the following beneficial effects.

[16] 1. The alternating magnetic field is generated in the coil by using current, so that the metal grinding balls generate induced eddy current for heating, which directly acts on the material powder. The heat does not act on other parts of the device, the direct heating is enabled, and the energy efficiency is high.

[17] 2. The number of grinding balls is large, the contact areas of the grinding balls with the powder materials are large, the overturning vibration during ball milling promotes the contact between the grinding balls and the powder materials, and the heat transfer is fast.

[18] 3. High-frequency power supply is adopted. Because of skin effect, the internal temperature of the metal grinding ball is low, and the heating is concentrated on the metal grinding ball surface, which is beneficial to transfer heat to the material powder.

Itis convenient to directly control the heating. When the power is cut off, the heating is stopped. No extra heat is stored inside the metal grinding balls, and the temperature control is accurate.

[19] 4. The wear-resistant high-chromium steel or high-temperature ferromagnetic materials can be selected to manufacture grinding balls according to the purpose of drying materials or high-temperature reaction as required, which has a wide range of application temperature and can be universally applied to the processing of various powder materials.

[20] 5. By integrating the power grinding and heating processes, the integration of the device is realized, and the occupied area of the device is reduced. Moreover, the compact device is beneficial to control gas tightness of the device. The device can not only process in gas atmosphere, but also can be introduced with protective gas or reaction gas as required, which has a wide application range.

[21] 6. In the process of using reactive gas to react with materials, the materials are turned over and ground while being heated, which can continuously peel the reaction products on the surface layer from the particles, improve the uniformity and reaction rate of high-temperature reaction, and improve the efficiency. At the same time, the fresh surface exposed due to material crushing during ball milling has high surface energy and high reaction activity, which is beneficial to improve the purity of reaction products.

[22] 7. The thermal insulation layer is between the coil layer and the powder materials, which takes into account the thermal insulation and energy conservation demands in the process of powder heat treatment and the heat dissipation demands of the coil.

[23] 8. The magnet yoke is distributed outside the magnetic induction coil, which not only fixes the magnetic induction coil, but also restricts the outward diffusion of induction magnetic leakage, improves the efficiency of induction heating. Further, the magnet yoke serves as a magnetic shield to ensure the environmental safety of the device.

[24] 9. The non-metallic and non-thermocouple temperature sensors are used to avoid the influence of electromagnetic induction on temperature measurement, and can achieve fine temperature control in combination with the power supply with adjustable power.

[25] 10. The wear-resistant layer is made of non-magnetic and non-conductive material to avoid electromagnetic shielding of the metal grinding balls, so that the induction heating is concentrated inside the cylinder body and the heat is directly transmitted to the target materials through the heat transfer, which is efficient and energy-saving.

BRIEF DESCRIPTION OF THE DRAWINGS

[26] FIG. 1 is a schematic structural diagram of a horizontal high-temperature ball milling device.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[27] Hereinafter, specific embodiments of the present disclosure will be explained with reference to the accompanying drawings.

[28] As shown in FIG. 1, the present disclosure provides a horizontal high-temperature ball milling device, which includes a supporting system, a driving transmission system, a heating ball milling system and a gas and material in-and-out control system.

[29] The heating ball milling system includes a cylinder body 11 and multiple metal grinding balls 12.

[30] The cylinder body 11 is transversely arranged, and left and right ends of the cylinder body 11 are provided with a feed inlet 111 and a feed outlet 112 respectively.

[31] A multi-layer structure is laid in a cylinder wall of the cylinder body 11, and includes a wear-resistant layer 16, a thermal insulation layer 15 and a magnet yoke coil layer.

[32] The wear-resistant layer 16 is located on the innermost side of the multi-layer structure. The thermal insulation layer 15 is located on an outer side of the wear-resistant layer 16 and is closely attached to the wear-resistant layer 16. The magnet yoke coil layer is located on an outer side of the thermal insulation layer 15 and is closely attached to the thermal insulation layer 15. The magnet yoke coil layer includes a magnet yoke 13 and a coil 14. The coil 14 is embedded on an inner side of the magnet yoke, that is, the coil 14 is fixed inside the magnet yoke 13 and is located on the inner side of the magnet yoke relative to the whole magnet yoke 13.

[33] Specifically, the wear-resistant layer 16 refers to a layer of wearing structure made of wear-resistant material. The material of the wear-resistant layer 16 is a non-magnetic and non-conductive material. The thermal insulation layer 15 refers to a layer of thermal insulation structure made of thermal insulation material. The magnet yoke 13 refers to a structure formed by stacking strip-shaped sheets made of soft magnetic material with relatively high magnetic permeability. The coil 14 is provided on the inner side of the magnet yoke 13, which is formed by winding an electromagnetic coil along a frame built inside the magnet yoke 13. The coil 14 is connected with an external high-frequency power supply through wires. The coil 14 is powered by a high-frequency alternating current power supply, the frequency range of the high-frequency alternating current power supply is 1000 Hz to 100000 Hz, and the power of the power supply is adjustable. The material of the metal grinding ball 12 is wear-resistant high chromium steel or nickel-based high-temperature alloy, which is wear-resistant high chromium steel at 300 celsius degrees or less and is nickel-based high-temperature alloy at 300 celsius degrees or more. The material of the wear-resistant layer 16 is a ceramic refractory material at 300 celsius degrees or more.

[34] The multi-layer structure in this embodiment can be added (for example, other functional layers are added), combined (for example, ceramic is used as wear-resistant layer and thermal insulation layer), or split (for example, the coil and magnet yoke are arranged separately, and the magnet yoke is located on the outer side of the coil) based on the actual application, or the order can be adjusted. However, it should be limited as follows: the wear-resistant layer is located at the innermost side of the multi-layer structure. The coil is located outside the thermal insulation layer or embedded in the outer side of the thermal insulation layer, which not only realizes system thermal insulation, but also gives consideration to coil heat dissipation. The coil is located inside the magnet yoke or embedded on the inner side of the magnet yoke to control the magnetic leakage and ensure the environmental safety of the system. For example,

the magnet yoke coil layer can also be embedded on the outer side of the thermal insulation layer, that is, the magnet yoke coil layer is shorter than the thermal insulation layer and is located in the middle part of the thermal insulation layer. The thermal insulation layer wraps the magnet yoke coil layer on the inner side and both left and right sides.

[35] Multiple metal grinding balls 12 are placed in the cylinder body 11.

[36] The feed outlet 112 is provided with a filter sieve or a filter grille, and the specification of the filter holes is larger than target product particles and smaller than the metal grinding balls 12, so as to filter out the target product and retain the metal grinding balls 12 during discharge.

[37] The cylinder body 11 is provided on the supporting system, and the driving transmission system drives the cylinder body 11 to roll around its transverse center line.

[38] In some embodiments, the supporting system includes a base 21, two brackets 22 and two bearings 23. The two brackets 22 are fixed on the base 21 and are oppositely arranged. The bearings 23 are provided respectively outside the feed inlet 111 and the feed outlet 112, which are at two ends of the cylinder body 11, and each of the feed inlet 111 and the feed outlet 112 is installed respectively on a corresponding one of the brackets 22 through a respective one of the bearings 23.

[39] The driving transmission system includes a motor 31, a reducer 32, a transmission gear 33 and a driven gear 34. The driven gear 34 is fixedly sleeved outside the cylinder body 11. The transmission gear 33 is located on an outer side of the driven gear 34 and meshed with the driven gear 34. The motor 31 drives the transmission gear 33 to rotate through the reducer 32, and the driven gear 34 and the cylinder body 11 rotate therewith.

[40] The gas and material in-and-out control system includes a feed inlet connector 41, a feed outlet connector 42, a feed inlet control unit 43, a feed outlet control unit 44, a gas inlet valve 45 and a gas outlet valve 46.

[41] The feed inlet connector 41 and the feed outlet connector 42 are connected and communicated with the feed inlet 111 and the feed outlet 112 of the cylinder body 11 through the respective bearings 23 respectively, and do not rotate when the cylinder body 11 rotates. The bearings 23 are airtight bearings to ensure the gas tightness of the cylinder body 11 during rolling.

[42] The feed inlet control unit 43 and the feed outlet control unit 44 are connected with the feed inlet connector 41 and the feed outlet connector 42 respectively, to control the material inlet and outlet rates of the materials and adjust the processing time of the materials in the cylinder body 11.

[43] The gas inlet valve 45 and the gas outlet valve 46 are provided on the feed inlet connector 41 and the feed outlet connector 42 respectively, to control the gas in and out as well as the flow rate of gas, thereby controlling the processing or reaction atmosphere of heating the material powder in the ball milling system.

[44] In some embodiments, both the feed inlet connector 41 and the feed outlet connector 42 are provided with a material inlet and outlet interface and a gas inlet and outlet interface. The feed inlet control unit 43 and the feed outlet control unit 44 are connected to the material inlet and outlet interface respectively, and the gas inlet valve 45 and the gas outlet valve 46 are provided on the gas inlet and outlet interface respectively.

[45] In operation, the driving transmission system drives the cylinder body 11 to roll, and materials and gas enter the cylinder body 11 from the feed inlet 111 through the gas and material in-and-out control system. The metal grinding balls 12 grind the materials in the rolling cylinder body 11. At the same time, the coil 14 is energized to generate an internal alternating magnetic field. The surfaces of the metal grinding balls 12 generate induced eddy current to heat the materials. The powder product, which has been heated and ground by balls, is discharged from the feed outlet 112 through the gas and material in-and-out control system.

[46] The coil 14 is placed outside the thermal insulation layer 15, so as to realize both thermal insulation of the system and the coil heat dissipation. The magnet yoke 13 surrounds the coil 14 from the outside to control the magnetic leakage and ensure the environmental safety of the system.

[47] The device further includes a non-metallic and non-thermocouple temperature sensors which is provided in the cylinder body to measure the temperature of the materials of the cylinder body. For example, a ceramic temperature sensor can be integrated on the wear-resistant layer, or an infrared transducer can be selected to pass through the feed inlet or the feed outlet or through an observation window setted on the cylinder body to measure the temperature of the materials in the heating ball milling system.

Claims

S12 - Conclusions

A horizontal high temperature ball mill device, comprising: a support system, a drive transmission system and a hot ball mill system; wherein the hot ball mill system includes a cylinder body and a plurality of metal crushing balls; wherein the cylinder body is disposed transversely, and a left end and a right end of the cylinder body are respectively provided with a supply inlet and a supply outlet; wherein a multilayer structure is provided in a cylinder wall of the cylinder body and includes a wear resistant layer, a thermal insulation layer and a magnet yoke coil layer; wherein the wear-resistant layer is located on an inner side of the multilayer structure, wherein the thermal insulation layer is located on an outer side of the wear-resistant layer, wherein the magnet yoke coil layer is located on an outer side of the thermal insulation layer or embedded in the outer side of the thermal insulation layer; wherein the magnet yoke coil layer comprises a magnet yoke and a coil, and wherein the coil is located on an inner side of the magnet yoke; wherein the coil is connected to a high frequency power supply; wherein the plurality of metal crushing balls are provided in the cylinder body; the cylinder body being provided on the support system, the drive transmission system driving the cylinder body to roll about a transverse centerline of the cylinder body; wherein the cylinder body rolls, and material and gas enter the cylinder body from the feed inlet such that the metal shatter balls crush the materials in the rolling cylinder body; and wherein the coil is energized with high frequency alternating current to simultaneously generate an alternating magnetic field in the cylinder body such that a surface of each of the metal crushing balls generates induced eddy currents to heat the materials.

A horizontal high temperature ball mill apparatus according to claim 1, wherein:

S13 - the wear-resistant layer has a non-magnetic and non-conductive material.

The horizontal high temperature ball mill apparatus according to claim 1, wherein: the support system comprises a base, two brackets and two bearings; the two brackets are fixed to the base and arranged opposite; the two bearings are respectively provided outside the feed inlet and the feed outlet, and each of the feed inlet and the feed outlet is installed on a corresponding one of the two brackets through a respective one of the two bearings.

The horizontal high temperature ball mill apparatus according to claim 3, wherein: the drive transmission system comprises a motor, a reducer, a transmission gear and a driven gear; the driven gear is fixedly encased on the cylinder body; the transmission gear is on an outer side of the driven gear and meshed with the driven gear; the motor drives the transmission gear through the reducer to rotate, and the driven gear and cylinder body rotate together with it.

The horizontal high temperature ball mill apparatus of claim 3, further comprising: a gas and material in-and-out control system, the system comprising a feed inlet connector, a feed outlet connector, a feed inlet control unit, a feed outlet control unit, a gas inlet valve, and a gas outlet valve includes; wherein the feed inlet connector and the feed outlet connector are respectively connected and communicated with the feed inlet and feed outlet of the cylinder body through a corresponding one of the two bearings, and are non-rotatable when the cylinder body rotates; wherein the feed inlet control unit and the feed outlet control unit are respectively connected to the feed inlet connector and the feed outlet connector to send the materials in and out; wherein the gas inlet valve and the gas outlet valve are provided on the supply inlet connector and the supply outlet connector, respectively, to direct the gas in and out.

The horizontal high-temperature ball mill apparatus according to claim 5, wherein: the two bearings are gas-tight bearings.

The horizontal high temperature ball mill apparatus according to claim 1, further comprising non-metallic and non-thermocouple temperature sensors provided in the cylinder body to measure a temperature of the materials of the cylinder body.

The horizontal high-temperature ball mill apparatus according to claim 1, wherein: the feed outlet is provided with a filter screen or a filter grille, and specification of the filter holes of the filter screen or the filter grille is larger than target product particles and smaller than the metal crushing balls.

The horizontal high-temperature ball mill apparatus according to claim 1, wherein: the coil layer is powered by a high-frequency AC power supply, a frequency range of the high-frequency AC power supply is 1000 Hz to 100000 Hz, and a power of the high-frequency AC power supply is adjustable.

The horizontal high-temperature ball mill apparatus according to claim 1, wherein: the metal crushing ball has, at 300 degrees Celsius or less, wear-resistant high-chromium steel material, or, at 300 degrees Celsius or more, nickel-based high-temperature alloy material; wherein the wear-resistant layer, at 300 degrees Celsius or more, has ceramic refractory material.