A pre-drying device for a flash calciner

Abstract

The present invention relates to the technical field of rare earth metallurgy, and particularly relates to a pre-drying device for a flash calciner, comprising: a drying bin having a first inlet and a first outlet; a reaction furnace having a first accommodating cavity, a second inlet, a second outlet and a third outlet, the second inlet being connected to the first outlet and a hot gas outlet, and at least one first nozzle being provided at the second inlet to simultaneously spray materials and hot gas into the reaction furnace for reaction, and the product being discharged through the second outlet; a pre-drying furnace having a second accommodating cavity, a third inlet, a fourth outlet and a fifth outlet, the third inlet being communicated with the third outlet, the fourth outlet being communicated with the first inlet, and at least one second nozzle being provided at the third inlet, and the tail gas being discharged through the fifth outlet; a connection structure with a power member is provided between the reaction furnace and the pre-drying furnace. The present invention provides a pre-drying device for a flash calciner with a small equipment volume, low energy consumption, high tail gas utilization rate and high drying efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of rare earth metallurgy, and particularly relates to a pre-drying device for a flash calciner. Background Art

[0002] Currently, most rare earth manufacturers use high-temperature tunnel kilns or pusher kilns to calcine rare earth oxalate to prepare rare earth oxides. The tunnel kiln or pusher kiln calcination technology is to load the rare earth oxalate material into bowls, place them on the pusher plates, and the pusher plates enter the tunnel kiln through the tunnel kiln track for calcination. After the calcination is completed and waiting for the temperature to drop to room temperature, it enters the mixer through a vibrating screen for mixing and bagging.

[0003] The tunnel kiln or pusher kiln calcination technology belongs to a static calcination method. The heat source provided is uneven, and in the calcination process, it is necessary to first heat the bowl containing rare earth oxalate, and then the bowl absorbs heat to heat the material for calcination. The heat transfer efficiency is low, the calcination time is about 30 hours, and the surface area of the tunnel kiln or pusher kiln is large, the heat dissipation is much, the energy consumption is large, and the direct energy consumption is about 450m 3 natural gas / tRE2O3; moreover, the bowls are easily damaged and the products are easily contaminated; at the same time, due to the long-term high-temperature environment of the materials, over-calcination often occurs, the product performance is poor, the particles are loose and easy to float in the air, and the loss is large when used; the tunnel kiln mainly relies on manual loading and unloading, the labor intensity is large, and the equipment is complex and large, and the materials required for construction are more, and the investment is large; the automation level of the tunnel kiln or pusher kiln is low and the quality control is difficult.

[0004] Therefore, the prior art provides a device for drying and calcining rare earth carbonate, including a feeding steel platform, a first screw feeder, a first cyclone separator, a pulse bag filter, a drying rotary kiln, a second cyclone separator, a tail gas induced draft fan, an exhaust pipe, a second screw feeder, pipe fittings, a screw feeder, a ventilation pipe, a calcination device, and a jacket water-cooled conveyor; the first screw feeder is arranged above the feeding steel platform; the top of the first screw feeder is provided with a feeding port; the drying rotary kiln and the calcination device are respectively provided with a transmission mechanism and a supporting wheel at the bottom. The calcination device directly leads the high-temperature gas generated by natural gas combustion into the drying rotary kiln to dry the rare earth carbonate, the tail gas utilization rate is low, the energy consumption is large, and it is directly dried with low efficiency. In addition, the direct calcination of rare earth carbonate has a long calcination time and the volume of the whole device is large. Summary of the Invention

[0005] Therefore, the technical problem to be solved by the present invention is to overcome the defects in the prior art that the tail gas utilization rate of the drying rotary kiln is low, the energy consumption is large, the drying efficiency is low, the calcination time is long, and the volume of the calcination device is large, so as to provide a pre-drying device for a flash calciner with reduced energy consumption, improved tail gas utilization rate, high drying efficiency, short calcination time, and small volume.

[0006] To solve the above technical problems, the present invention provides a pre-drying device for a flash calciner, comprising:

[0007] A drying bin having a first inlet and a first outlet;

[0008] A reaction furnace having a first accommodating cavity, a second inlet, a second outlet and a third outlet, wherein the second inlet is connected to the first outlet and a hot gas outlet, and at least one first nozzle is provided at the second inlet to simultaneously inject materials and hot gas into the reaction furnace for reaction, and the product is discharged through the second outlet;

[0009] A pre-drying furnace having a second accommodating cavity, a third inlet, a fourth outlet and a fifth outlet, wherein the third inlet is communicated with the third outlet, the fourth outlet is communicated with the first inlet, and at least one second nozzle is provided at the third inlet, and the tail gas is discharged through the fifth outlet;

[0010] A connection structure provided between the reaction furnace and the pre-drying furnace, having a power member, and the power member is adapted to convey the product to the second outlet.

[0011] Optionally, the power member is a rotary kiln, and the connection structure further includes a flue communicated with the rotary kiln, the second outlet is provided at the connection of the rotary kiln and the flue, and the third outlet is provided at the other end of the flue.

[0012] Optionally, the first end of the rotary kiln connected to the reaction furnace is higher than the second end connected to the flue, and the flue is bent.

[0013] Optionally, a chute is further provided between the reaction furnace and the rotary kiln.

[0014] Optionally, the inclination of the chute is 1% - 6%.

[0015] Optionally, the power member is a chain bucket machine, and the connection structure further includes a cylinder body and a flue communicated with the cylinder body, the second outlet is provided at the connection of the cylinder body and the flue, the third outlet is provided at the other end of the flue, and the chain bucket machine is arranged in the cylinder body.

[0016] Optionally, a cooling structure communicated with the second outlet and a reforming and mixing device connected to the cooling structure are further included.

[0017] Optionally, a sprayer and a stirring paddle are provided in the reforming and mixing device.

[0018] Optionally, a first dust collector, a second dust collector and a spray tower are sequentially communicated, the first dust collector is communicated with the fifth outlet, and the materials collected by the first dust collector and the second dust collector are conveyed back to the drying bin.

[0019] Optionally, it further includes an induced draft fan connected to the spray tower.

[0020] The technical solution of the present invention has the following advantages:

[0021] 1. For the flash calcination furnace pre-drying device provided by the present invention, the material and hot gas are simultaneously sprayed into the furnace body through the first nozzle to react, and most of the calcination reaction is completed within a few seconds. The product is discharged through the second outlet under the action of the power component, and the tail gas is discharged through the third outlet. When the product moves towards the second outlet under the action of the power component, some incompletely calcined materials contact each other to further complete the calcination reaction, and most of the soot gradually settles. The entire calcination time is significantly shortened, the calcination is complete, the product yield is high, and there is no need to set the flash reaction furnace very high or use a rotary kiln with a large diameter and length to achieve complete calcination, which greatly reduces the volume of the furnace body, reduces equipment investment, and improves production efficiency; the material to be dried enters the pre-drying furnace together with the tail gas discharged through the third outlet through the second nozzle. The material to be dried is sprayed in a dispersed state and fully contacts the hot tail gas, with a fast heat transfer speed and high drying efficiency, and the drying process is completed during the falling process; directly using the calcination tail gas for drying in the furnace has a short heat transfer distance, less heat loss, and full utilization of heat, enabling deep drying of the material; reducing the equipment for conveying the dust-containing tail gas outside the furnace, avoiding blockage of the conveying pipeline, and making the entire device more compact and reducing the floor area; there is no need to separate the soot in the tail gas from the dried material, and they are mixed and sent back to the drying bin together.

[0022] 2. For the flash calcination furnace pre-drying device provided by the present invention, the setting of the rotary kiln enables the material to utilize the heat of the high-temperature product after flash calcination itself and further fully contact with the high-temperature gas. At the same time, using the driving force generated during the rotation of the rotary kiln, the material is tumbled and moved forward, strengthening the contact between the materials, enabling some incompletely calcined materials to further complete the calcination reaction, and improving the calcination efficiency while realizing material transmission.

[0023] 3. For the flash calcination furnace pre-drying device provided by the present invention, the setting of the chute enables the material in the reaction furnace to smoothly enter the rotary kiln under the action of gravity, and enables the inclination angle of the heavier rotary kiln to be smaller, making the entire device more stable.

[0024] 4. For the flash calcination pre-drying device provided by the present invention, multiple dust collectors are combined with the spray tower to treat the tail gas, making the dust content of the tail gas lower than 5mg / m 3 , and the total product yield is higher than 99.5%. Description of the Drawings

[0025] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the specific 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.

[0026] Figure 1 Schematic diagram of the pre-drying device of the flash calciner provided by the present invention;

[0027] Figure 2 is Figure 1 Partial enlarged schematic diagram of;

[0028] Figure 3 Schematic diagram of another embodiment of the power component.

[0029] Explanation of reference numerals:

[0030] 1, drying bin; 2, reaction furnace; 3, pre-drying furnace; 4, first nozzle; 5, chute; 6, rotary kiln; 7, flue; 8, second nozzle; 9, first dust collector; 10, spray tower; 11, induced draft fan; 12, bag dust collector; 13, cartridge dust collector; 14, cooling structure; 15, modification mixer; 16, sprayer; 17, stirring paddle; 18, chain bucket machine; 19, cylinder. Specific embodiments

[0031] The following will clearly and completely describe the technical solutions of the present invention with reference to the drawings. Obviously, the described embodiments are some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0032] In addition, the technical features involved in different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0033] Such as Figure 1 and 2A specific embodiment of the flash calcination furnace pre-drying device shown includes a drying bin 1, a reaction furnace 2, a connection structure, and a pre-drying furnace 3 that are connected in sequence, and can be used for the calcination of rare earth oxalates or rare earth carbonates or other oxalates or other carbonates. Rare earth oxalates refer to at least one of lanthanum oxalate, cerium oxalate, praseodymium oxalate, neodymium oxalate, promethium oxalate, samarium oxalate, europium oxalate, gadolinium oxalate, terbium oxalate, dysprosium oxalate, holmium oxalate, erbium oxalate, thulium oxalate, ytterbium oxalate, lutetium oxalate, scandium oxalate, and yttrium oxalate; rare earth carbonates refer to at least one of lanthanum carbonate, cerium carbonate, praseodymium carbonate, neodymium carbonate, promethium carbonate, samarium carbonate, europium carbonate, gadolinium carbonate, terbium carbonate, dysprosium carbonate, holmium carbonate, erbium carbonate, thulium carbonate, ytterbium carbonate, lutetium carbonate, scandium carbonate, and yttrium carbonate; oxalates refer to at least one of cobalt oxalate, nickel oxalate, manganese oxalate, lithium oxalate, zinc oxalate, iron oxalate, and copper oxalate; carbonates refer to at least one of cobalt carbonate, nickel carbonate, manganese carbonate, lithium carbonate, zinc carbonate, iron carbonate, and copper carbonate.

[0034] The drying bin 1 is conical, has a first inlet at the upper part and a first outlet at the corresponding position at the lower part, and the cross-sectional area of the first inlet is larger than that of the first outlet, and is used for temporarily storing the dried material.

[0035] The reaction furnace 2 is cylindrical, has a first accommodating cavity, a second inlet, a second outlet, and a third outlet. The second inlet is provided at the top of the first accommodating cavity, is connected to the first outlet and the hot gas outlet, and a first nozzle 4 is provided at the second inlet to spray the hot gas and the material output from the first outlet into the reaction furnace 2 at the same time for reaction.

[0036] The connection structure includes an inclined chute 5 communicated with the bottom of the reaction furnace 2, a power member communicated with the inclined chute 5, and a flue 7 communicated with the power member. The power member is a rotary kiln 6. One end of the inclined chute 5 connected to the reaction furnace 2 is higher than the other end connected to the rotary kiln 6. Specifically, the inclination of the inclined chute 5 is 1% - 6%. The first end of the rotary kiln 6 connected to the inclined chute 5 is higher than the second end connected to the flue 7. The product smoothly enters the rotary kiln 6 under the action of gravity and the guiding action of the inclined chute. The flue 7 is bent and provided, including a first vertical part connected to the rotary kiln 6, a second vertical part connected to the pre-drying furnace 3, and a bent transition part for connecting the first vertical part and the second vertical part, so as to minimize the inclination angles of the inclined chute 5 and the rotary kiln 6, make the structure of the whole device more compact, and reduce the occupied space. The second outlet is provided at the connection between the rotary kiln 6 and the flue 7, and the third outlet is provided at the other end of the flue 7. The product is discharged through the second outlet, and the tail gas is discharged through the third outlet.

[0037] The pre-drying furnace 3 is arranged side by side with the reaction furnace 2 and has a second accommodation chamber, a third inlet, a fourth outlet and a fifth outlet. The third inlet is provided at the top of the second accommodation chamber and is communicated with the third outlet. Two second nozzles 8 are provided at the third inlet. The second nozzles 8 are connected to the material conveying device to convey the material to be dried into the second accommodation chamber. The fourth outlet is provided at the bottom of the second accommodation chamber and is communicated with the first inlet to convey the dried material to the drying bin 1 for temporary storage. The fifth outlet is provided at the bottom of the side wall of the second accommodation chamber to discharge the dried tail gas outwards.

[0038] To further treat the tail gas, it further includes a first dust collector 9, a second dust collector, a spray tower 10 and a draft fan 11 which are connected in sequence. The first dust collector 9 is communicated with the fifth outlet. The first dust collector 9 is a cyclone dust collector. The second dust collector includes a bag dust collector 12 and a cartridge dust collector 13 which are arranged in sequence. The air outlet of the cartridge dust collector 13 is connected to the inlet of the spray tower 10. The outlet of the spray tower 10 is connected to the inlet of the draft fan 11. The dust-removed tail gas is led out and discharged from the outlet of the draft fan 11. The materials collected by the first dust collector 9 and the second dust collector are conveyed back to the drying bin 1 through the bottom opening.

[0039] It further includes a cooling structure 14 communicated with the second outlet and a reforming and mixing device 15 connected to the cooling structure 14. A plurality of feeding pipes are arranged inside the cooling structure 14. Air is used as the medium to cool the product in a non-contact manner. The material is conveyed from top to bottom in the pipe, and the air is conveyed from bottom to top outside the pipe. The air and the material move in opposite directions. The heated air after heat exchange is conveyed to the first nozzle 4. The outlet of the cooling structure 14 is communicated with the reforming and mixing device 15. A sprayer 16 is provided at the inlet at the top of the reforming and mixing device 15. Multiple sprayers 16 can be set as needed. During the mixing process, a set amount of water is sprayed according to the amount of the incoming material to control the final moisture content of the product. A stirring paddle 17 is also provided in the reforming and mixing device 15 to stir the material. The reformed material is discharged and collected through the finished product outlet at the bottom to obtain the final product.

[0040] The rare earth oxalate raw material enters the second cavity through the second nozzle of the pre-drying furnace and is quickly dried by the tail gas collected by the flue during the falling process. It is discharged through the fourth outlet at the bottom of the second cavity and conveyed to the drying bin for standby. The dry material in the drying bin and the hot air from the cooling structure are sprayed into the reaction furnace through the first nozzle. During the falling process, a decomposition reaction quickly occurs to generate rare earth oxides, which are guided by the chute into the rotary kiln for further reaction. The product is discharged through the second outlet to the cooling structure, and after being forced to cool by air, it enters the reforming and mixing device. The final moisture content of the product is controlled by spraying water with the sprayer and fully mixed, and then discharged from the discharge port of the reforming and mixing device to obtain the final product.

[0041] The calcination tail gas rises along the flue until it enters the pre-drying furnace and serves as the heat source for material drying. After heat exchange with the material, the tail gas enters the cyclone dust collector for dust collection, then enters the bag dust collector for dust collection, and then enters the cartridge dust collector for further dust collection. Finally, it is led out and emptied by the induced draft fan after being sprayed and dust-removed in the spray tower. The products collected by the cyclone dust collector and the bag dust collector are conveyed back to the drying bin together through the bottom opening.

[0042] As an alternative embodiment, such as Figure 3 shown, the power component is the chain bucket machine 18. The connection structure further includes a cylinder body 19 and a flue 7 communicating with the cylinder body 19. The second outlet is arranged at the connection of the cylinder body 19 and the flue 7, and the third outlet is arranged at the other end of the flue 7. The chain bucket machine 18 is arranged in the cylinder body 19. The cylinder body 19 is horizontally arranged, and the chain bucket machine 18 conveys the product to the second outlet under the action of driving force.

[0043] As an alternative embodiment, the second nozzle can be a plurality of nozzles arranged circumferentially around the third inlet.

[0044] As an alternative embodiment, a heating jacket is sleeved outside the reaction furnace, or a heat source is arranged inside. The heat source is electricity, natural gas, plasma, microwave or heavy oil.

[0045] The present invention combines flash rapid calcination with rotary high-efficiency heat preservation and material pre-drying organically, realizes the rapid calcination of rare earth oxalate to produce rare earth oxides, ensures the calcination quality of the product, and at the same time uses the high-temperature calcination tail gas to rapidly pre-dry the raw materials, greatly shortening the process, reducing energy consumption and reducing carbon emissions. The comprehensive utilization of energy has low heat consumption, a small heat dissipation area of the furnace body, good airtightness, and a high utilization rate of tail gas waste heat, and the heat consumption is almost close to the theoretical value. By setting the modified mixer, the final water content of the product is controlled, which greatly changes the particle viscosity of the product, is not easy to generate dust and float, and the product has good performance. The equipment has a large processing capacity, simple operation, is suitable for automated continuous production, and requires less manual labor. The equipment has a simple structure, small floor area, is easy to manufacture, and has a small investment. The system operates in a closed manner, without dust leakage, and has no pollution to the environment.

[0046] Obviously, the above embodiments are only examples clearly described and not limitations on the implementation manners. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to enumerate all the implementation manners here. And the obvious changes or modifications derived therefrom are still within the protection scope of the present invention.

Claims

1. A pre-drying device for a flash calciner, characterized in that, Comprising: A drying bin (1) having a first inlet and a first outlet; A cooling structure (14) having a hot gas outlet; A reaction furnace (2) having a first accommodating cavity, a second inlet, a second outlet and a third outlet, the second inlet being connected to the first outlet and the hot gas outlet, and at least one first nozzle (4) being provided at the second inlet to simultaneously inject materials and hot gas into the reaction furnace (2) for reaction, and the product being discharged through the second outlet, the cooling structure (14) being communicated with the second outlet; A pre-drying furnace (3) having a second accommodating cavity, a third inlet, a fourth outlet and a fifth outlet, the third inlet being connected to the third outlet, the fourth outlet being connected to the first inlet, and at least one second nozzle (8) being provided at the third inlet, and the tail gas being discharged through the fifth outlet; A connecting structure provided between the reaction furnace (2) and the pre-drying furnace (3) and having a power member adapted to convey the product to the second outlet; The power member is a rotary kiln (6), and the connecting structure further includes a flue (7) communicated with the rotary kiln (6), the second outlet being provided at the connection of the rotary kiln (6) and the flue (7), and the third outlet being provided at the other end of the flue (7); The first end of the rotary kiln (6) connected to the reaction furnace (2) is set higher than the second end connected to the flue (7), and the flue (7) is bent; It further includes a chute (5) provided between the reaction furnace (2) and the rotary kiln (6).

2. The pre-drying device for a flash calciner according to claim 1, characterized in that, The inclination of the chute (5) is 1% - 6%.

3. The pre-drying device of the flash calciner according to any one of claims 1-2, characterized in that, It further includes a reforming mixer (15) connected to the cooling structure (14).

4. The flash calciner pre-drying device according to claim 3, characterized in that, A sprayer (16) and a stirring paddle (17) are provided in the reforming mixer (15).

5. The pre-drying device of the flash calciner according to claim 4, characterized in that, It further includes a first dust collector (9), a second dust collector and a spray tower (10) connected in sequence, the first dust collector (9) being communicated with the fifth outlet, and the materials collected by the first dust collector (9) and the second dust collector being conveyed back to the drying bin (1).

6. The pre-drying device of the flash calciner according to claim 5, characterized in that, It further includes a induced draft fan (11) connected to the spray tower (10).

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