Kiln body for sintering lithium iron phosphate and flue gas recycling system

Abstract

The invention relates to a kiln body for lithium iron phosphate sintering and a flue gas recycling system, and belongs to the technical field of lithium iron phosphate sintering, the kiln body comprises an inner kiln and an outer kiln, the inner kiln is obliquely arranged, the inner kiln comprises a preheating pipe and a sintering pipe, the preheating pipe and the sintering pipe are sequentially arranged in the material conveying direction and are communicated, a spiral convex preheating bin is arranged outside the preheating pipe, and the outer kiln is arranged in the outer kiln. A plurality of protrusions are arranged on the outer wall of the outwards-protruding preheating bin at intervals in the length direction of the outwards-protruding preheating bin, a spiral preheating channel is formed between the inner wall of the outer kiln and the outer wall of the outwards-protruding preheating bin, and a tubular sintering space is formed between the inner wall of the outer kiln and the outer wall of the sintering pipe. The sintering space is communicated with the preheating channel through an external pipeline, a plurality of elastic cleaning strips are arranged at the positions, at the preheating channel, of the inner wall of the outer kiln at intervals, the elastic cleaning strips abut against the outer wall of the outwards-protruding preheating bin, intermittent impact is conducted, materials accumulated in the preheating bin are knocked away, accumulation and caking are avoided, and meanwhile the materials are preheated in advance.

Description

TECHNICAL FIELD

[0001] The application relates to the lithium iron phosphate sintering technical field, in particular to a kiln body for lithium iron phosphate sintering and a flue gas recycling system. BACKGROUND

[0002] In the preparation of lithium iron phosphate, the precursor of lithium iron phosphate is generally ground by a wet method to obtain a nanoscale particle size, then the ground slurry needs to be spray dried, and finally the dried powder material is put into a sintering kiln body for sintering.

[0003] The existing technology relates to a furnace kiln flue gas waste heat recovery device, which comprises a cylinder box, an annular heating box is fixed in the cylinder box, the annular heating box is provided with a water inlet and a water outlet, a corrugated inner plate is arranged on one side plate of the annular heating box close to the center of the cylinder box, a motor is installed on one side of the cylinder box close to the air inlet, and a driving rod is installed on the driving end of the motor.

[0004] The above-mentioned and existing kiln body structure using a bellows to increase the heat exchange area, although the heat exchange area is increased when facing the lithium iron phosphate sintering process, but due to the deep and fixed groove structure, the material is easy to form a dead zone at the bottom of the groove during tumbling, and the dust in the external flue gas is also easy to deposit in the concave part of the outer wall of the bellows, resulting in the decrease of the heat conduction efficiency with the use time. SUMMARY

[0005] The application provides a kiln body for lithium iron phosphate sintering and a flue gas recycling system, which can solve the problems that lithium iron phosphate is easy to form agglomerates in the dead zone and the heat exchange efficiency is not high when using a corrugated kiln body to sinter lithium iron phosphate and recycling waste heat by using flue gas.

[0006] The technical scheme of the application is as follows: a kiln body for lithium iron phosphate sintering, comprising: An inner kiln is arranged obliquely, the inner kiln comprises a preheating pipe and a sintering pipe, the preheating pipe and the sintering pipe are sequentially arranged and communicated along the material conveying direction, the preheating pipe is externally provided with a spiral-shaped outer convex preheating bin, the outer convex preheating bin is hollow inside and communicated with the inside of the preheating pipe, and a plurality of protrusions are arranged on the outer wall of the outer convex preheating bin along the length direction of the outer convex preheating bin; The outer kiln is arranged outside the inner kiln, one side of the outer kiln is provided with a rotating device connected with the inner kiln, the outer convex preheating bin is provided with a flexible layer on the outer edge, and the flexible layer is in interference fit with the inner wall of the outer kiln, a spiral preheating channel is formed between the inner wall of the outer kiln and the outer wall of the outer convex preheating bin, a tubular sintering space is formed between the inner wall of the outer kiln and the outer wall of the sintering pipe, the sintering space is communicated with the preheating channel through an external pipeline to pass the flue gas generated by sintering into the preheating channel to preheat the material, a plurality of elastic cleaning strips are arranged at the preheating channel of the inner wall of the outer kiln, one end of the elastic cleaning strip extends to contact the outer convex preheating bin, so that the elastic cleaning strip is elastically deformed under the resistance of the convex and intermittently hits the outer convex preheating bin.

[0007] By adopting the above scheme, the spiral outer convex preheating bin can increase the contact area between the high-temperature flue gas and the inner kiln, and the spiral preheating channel is formed between the outer convex preheating bin and the inner wall of the outer kiln, thereby playing a role in guiding the high-temperature flue gas, so that the high-temperature flue gas can stay outside the preheating pipe for a longer time to obtain a longer heat exchange time, thereby improving the heat exchange efficiency of preheating by using high-temperature flue gas. Meanwhile, the convex is arranged outside the outer convex preheating bin, the rotating device can drive the inner kiln to rotate to improve the uniformity of material preheating and sintering, the convex outside the outer convex preheating bin can intermittently extrude the elastic cleaning strip, the elastic cleaning strip is always in contact with the outer wall of the outer convex preheating bin, and can scrape off the dust on the outer wall of the outer convex preheating bin while being in relative movement with the outer convex preheating bin, and can also be in contact with the convex arranged at intervals to intermittently hit the outer convex preheating bin, so that the material accumulated in the outer convex preheating bin is knocked apart to avoid accumulation and caking, thereby improving the conveying efficiency of the material and the uniformity of sintering.

[0008] In an embodiment of the present application, the outer kiln side wall is provided with a plurality of combustion ports at the sintering space, the combustion ports are connected with the combustion nozzle through a combustion pipe, the outer kiln is provided with an air inlet at one end of the preheating channel and an air outlet at the other end, and the air inlet is communicated with the sintering space through the external pipeline.

[0009] By adopting the above scheme, a plurality of combustion ports are arranged at the sintering space and connected with the combustion machine, so that the preheated material can be sintered at the sintering space, and the rotating inner kiln can also improve the uniformity of the material during sintering.

[0010] In one embodiment of the present application, the pitch of the outer convex preheating bin gradually decreases along the material conveying direction, and the outer kiln inner wall is provided with a heat insulation ring which is sleeved outside the inner kiln and located between the preheating pipe and the sintering pipe.

[0011] By adopting the above scheme, the heat insulation ring is arranged between the preheating pipe and the sintering pipe, so that the high-temperature flue gas cannot flow horizontally from the sintering space to the preheating channel, and the air inlet and air outlet arranged at both ends of the preheating channel are matched, so as to realize the directional flow guiding effect of the high-temperature flue gas in the preheating channel, facilitate the prolongation of the residence time of the high-temperature flue gas in the preheating channel, and improve the heat exchange efficiency of the flue gas. Meanwhile, with the heat exchange, the pitch of the outer convex preheating bin at the end of the preheating pipe is reduced, so as to increase the residence time of the high-temperature flue gas at the end of the preheating pipe, and then the material along the length direction of the preheating pipe is preheated more uniformly, thereby improving the uniformity of the material preheating.

[0012] In one embodiment of the present application, the elastic cleaning strip comprises: a fixed seat, one end of the fixed seat is fixedly connected to the inner wall of the outer kiln, and the other end is fixedly connected with an elastic member; a cleaning rod, one end of the cleaning rod is connected with the elastic member, and the other end extends to the outer wall of the outer convex preheating bin and is in contact with the outer wall of the outer convex preheating bin, and a rough layer is arranged outside the cleaning rod for scraping the accumulated dust on the outer part of the outer convex preheating bin.

[0013] By adopting the above scheme, when the spiral outer convex preheating bin rotates with the inner kiln, the outer convex preheating bin can continuously scrape off the dust accumulated on the outer part of the outer convex preheating bin through the resistance and relative movement with the cleaning rod. Meanwhile, when passing through the protrusion, the protrusion can extrude the cleaning rod and drive the elastic member to further deform elastically and accumulate elastic potential energy. After the cleaning rod is separated from the mutual extrusion of the protrusion, the cleaning rod impacts the outer convex preheating bin under the elastic force of the elastic member, so as to knock the material accumulated in the outer convex preheating bin, thereby avoiding the caking of the material in the outer convex preheating bin.

[0014] In one embodiment of the present application, the rough layer comprises: a flexible layer, the flexible layer is coaxially assembled outside the cleaning rod; a plurality of dust scraping protrusions, the dust scraping protrusions are assembled on the surface of the flexible layer and are distributed at intervals along the circumference of the flexible layer.

[0015] By adopting the above scheme, the flexible layer can deform according to the surface concave-convex condition of the outward convex preheating bin, so that the ash scraping protrusion arranged outside the flexible layer can be fitted according to the surface arc of the outward convex preheating bin, the ash scraping area can be increased when the preheating bin and the cleaning rod move relative to each other, and then the heat exchange efficiency between the high-temperature flue gas and the preheating pipe can be improved.

[0016] The second object of the present application is to provide a flue gas recycling system for lithium iron phosphate sintering.

[0017] The technical scheme is as follows: a flue gas recycling system for lithium iron phosphate sintering, comprising a kiln body for lithium iron phosphate sintering, a feeding device, and a natural gas heat exchange device, the inlet end of the natural gas heat exchange device is connected with the gas outlet, the feeding device comprises a pre-stirring assembly with an internal cavity, the pre-stirring assembly is communicated with the natural gas heat exchange device through a connecting piece, and is used for stirring the material and preheating the material at the same time, and the combustion machine is communicated with the natural gas pipe network through the natural gas heat exchange device.

[0018] By adopting the above scheme, the natural gas heat exchange device is arranged in cooperation with the feeding device, so that the high-temperature flue gas generated from the sintering space first passes through the preheating channel outside the preheating pipe to perform first heat exchange, the flue gas after the first heat exchange is introduced into the natural gas heat exchange device to perform second heat exchange on the natural gas, so as to preheat the natural gas in advance and improve the combustion efficiency of the combustion machine, and then the flue gas after the second heat exchange is introduced into the pre-stirring assembly of the feeding device, so that the pre-stirring assembly is used for preheating the material in the material bin three times.

[0019] In one embodiment of the present application, the feeding device further comprises: a material bin, the pre-stirring assembly is arranged inside the material bin, a lower end of the material bin is provided with a discharging pipe, the discharging pipe is provided with a control valve, a driving member is arranged above the material bin, the driving member is connected with the pre-stirring assembly and is used for driving the pre-stirring assembly to rotate; a weighing feeder, one end of the weighing feeder is communicated with the discharging pipe, and the other end of the weighing feeder is communicated with the internal kiln.

[0020] By adopting the above scheme, the pre-stirring assembly with continuous rotation is arranged inside the material bin, the inside of the pre-stirring assembly is hollow, and the flue gas flowing out of the natural gas heat exchange device is introduced into the pre-stirring assembly, so that the pre-stirring assembly can continuously stir the material in the material bin and preheat the material in the material bin at the same time, so that the material does not form a lump in the material bin, and the material has a certain temperature before entering the sintering, which is convenient for faster temperature rising and sintering.

[0021] In one embodiment of the present application, the pre-stirring assembly comprises: a stirring pipe, one end of which extends to the outside of the upper end of the bin and is connected with the driving shaft of the driving member, and the other end of which extends to the outside of the lower end of the bin and is in communication with the connecting member; a stirring blade, which is hollow inside and coaxially connected with the stirring pipe.

[0022] By adopting the above scheme, the stirring pipe and the stirring blade are both hollow inside, so that when the stirring pipe and the stirring blade stir the material in the bin, the high-temperature flue gas inside the stirring blade can be used to uniformly preheat the material in the bin, improving the efficiency of preheating the material in the bin and not affecting the stirring effect of the material.

[0023] In one embodiment of the present application, the connecting member comprises: a connecting ring, two of which are coaxially rotatably connected at the two ends of the stirring pipe, and a flow passage is formed in the inside of the connecting ring; a connecting pipe, two of which are provided, one end of each of the two connecting pipes is in communication with the two ends of the stirring pipe through the two connecting rings respectively, and the other end of each of the two connecting pipes is in communication with the natural gas heat exchange device and the tail gas treatment equipment respectively.

[0024] By adopting the above technical scheme, the high-temperature flue gas after secondary heat exchange in the natural gas heat exchange device can pass through one of the connecting pipes into the connecting ring, enter the inside of the stirring pipe through the flow passage in the inside of the connecting ring, and then be dispersed into the inside of each stirring blade by the stirring pipe, so that the rotation of the stirring pipe itself is not affected, and the stirring blades can be used to preheat the material in the bin for subsequent sintering work.

[0025] In one embodiment of the present application, the natural gas heat exchange device comprises a gas heat exchanger and a gas pump, the inlet end of the gas heat exchanger is in communication with the gas outlet through the gas pump, and the gas outlet end of the gas heat exchanger is in communication with the other end of one of the connecting pipes.

[0026] By adopting the above scheme, by providing the gas heat exchanger and the gas pump, the gas pump provides power for the flow of high-temperature flue gas in the whole system, so that after the high-temperature flue gas preheats the material in the kiln, the high-temperature flue gas with residual heat can be introduced into the gas heat exchanger to preheat the natural gas, improving the utilization rate of heat.

[0027] In summary, the present application includes at least one of the following beneficial technical effects: by adopting the spiral-shaped outer convex preheating bin, the outer wall of the outer convex preheating bin and the inner wall of the outer kiln and the outer wall of the inner kiln form a preheating channel with a spiral shape, and the high-temperature flue gas generated by sintering is directed into the preheating channel, realizing spiral flow guiding of the high-temperature flue gas outside the preheating pipe, improving the heat exchange area, and also improving the residence time of the flue gas outside the preheating pipe, and improving the heat exchange efficiency of the flue gas.

[0028] By arranging the elastic cleaning strip outside the outer convex preheating bin, the elastic cleaning strip is always in contact with the outer convex preheating bin, so that the elastic cleaning strip can continuously scratch and impact the outer convex preheating bin while the inner kiln rotates, thereby scratching the dust outside the outer convex preheating bin and preventing the accumulated dust from affecting the heat exchange of the flue gas. At the same time, through the transmission of vibration, the materials accumulated inside the outer convex preheating bin are scattered, preventing the materials from accumulating inside the outer convex preheating bin and forming dead zones and clumps, thereby improving the sintering effect and conveying efficiency of the materials.

[0029] By sequentially passing the flue gas generated by sintering into the preheating channel, the natural gas heat exchange device, and the pre-mixing assembly, the heat in the flue gas is utilized and managed according to the heat requirements of different substances in the process flow, thereby improving the sintering efficiency of the materials, preheating the natural gas to improve the combustion efficiency of the combustion machine, and preheating the materials inside the bin to prevent the materials from clumping inside the bin while further improving the sintering efficiency of the materials. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 is a cross-sectional view of a kiln body outer kiln for lithium iron phosphate sintering provided in an embodiment of the present application; Figure 2 is a cross-sectional view of a kiln body inner kiln for lithium iron phosphate sintering provided in an embodiment of the present application; Figure 3 is Figure 2 is an enlarged schematic view of part A in Figure 4 is a cross-sectional view of an elastic cleaning strip of a kiln body for lithium iron phosphate sintering provided in an embodiment of the present application; Figure 5 is a cross-sectional view of a flexible layer of a kiln body for lithium iron phosphate sintering provided in an embodiment of the present application; Figure 6 is a flowchart of a flue gas recycling system for lithium iron phosphate sintering provided in an embodiment of the present application; Figure 7 is a cross-sectional view of a bin of a flue gas recycling system for lithium iron phosphate sintering provided in an embodiment of the present application.

[0031] Explanation of reference signs: 1, inner kiln; 11, preheating pipe; 12, sintering pipe; 13, outer convex preheating bin; 131, convex; 132, flexible layer; 2, outer kiln; 21, combustion port; 22, air inlet; 23, air outlet; 24, heat insulation ring; 3, preheating channel; 4, sintering space; 5, external pipeline; 6, elastic cleaning strip; 61, fixing seat; 62, elastic member; 63, cleaning rod; 64, rough layer; 641, flexible layer; 642, dust scraping convex block; 7, feeding device; 71, pre-stirring assembly; 711, stirring pipe; 712, stirring blade; 72, bin; 721, discharging pipe; 73, weighing feeder; 74, connecting piece; 741, connecting ring; 742, connecting pipe; 8, natural gas heat exchange device; 81, gas heat exchanger; 82, gas pump. DETAILED DESCRIPTION

[0032] The following will be described in detail below with reference to the accompanying drawings. Figures 1-7 A lithium iron phosphate sintering kiln body and flue gas recycling system provided by the present application is further described in detail.

[0033] The lithium iron phosphate sintering kiln body provided in the embodiments of the present application comprises an inner kiln 1 and an outer kiln 2.

[0034] The inner kiln 1 is obliquely arranged, the inner kiln 1 comprises a preheating pipe 11 and a sintering pipe 12, the preheating pipe 11 and the sintering pipe 12 are sequentially arranged and communicated along the material conveying direction, the preheating pipe 11 is externally provided with a spiral-shaped outer convex preheating bin 13, the outer convex preheating bin 13 is internally hollow and communicated with the inside of the preheating pipe 11, a plurality of protrusions 131 are arranged on the outer wall of the outer convex preheating bin 13 along the length direction of the outer convex preheating bin 13, the outer kiln 2 is sleeved outside the inner kiln 1, one side of the outer kiln 2 is provided with a rotating device connected with the inner kiln 1, the outer edge of the outer convex preheating bin 13 is provided with a flexible layer 132, and the outer convex preheating bin 13 is in interference fit with the inner wall of the outer kiln 2 through the flexible layer 132, a spiral-shaped preheating channel 3 is formed between the inner wall of the outer kiln 2 and the outer wall of the outer convex preheating bin 13, a tubular sintering space 4 is formed between the inner wall of the outer kiln 2 and the outer wall of the sintering pipe 12, the sintering space 4 is communicated with the preheating channel 3 through an external pipeline 5, so that the flue gas generated by sintering is introduced into the preheating channel 3 to preheat the material, a plurality of elastic cleaning strips 6 are arranged on the inner wall of the outer kiln 2 at the preheating channel 3, one end of the elastic cleaning strip 6 extends to contact the outer convex preheating bin 13, so that the elastic cleaning strip 6 is elastically deformed under the resistance of the protrusion 131 and intermittently impacts the outer convex preheating bin 13, the spiral-shaped outer convex preheating bin 13 is arranged at the front end of the sintering pipe 12, and the protrusions 131 are arranged at the outside of the outer convex preheating bin 13, so that the elastic cleaning strip 6 is always in contact with the outer wall of the outer convex preheating bin 13 and intermittently impacts the outer convex preheating bin 13, thereby making the material accumulated in the inner part of the outer convex preheating bin 13 be knocked apart, avoiding accumulation and caking, and preheating the material in advance to improve the sintering effect of the material.

[0035] In the embodiment, the rotating device can be a combination of a servo motor and a reduction box, the driving shaft of the servo motor is connected with the input shaft of the reduction box, and the output shaft of the reduction box is connected with the inner kiln 1 through a shaft coupling to drive the inner kiln 1 to rotate in the outer kiln 2; The flexible layer 132 can be a graphite component, so that the outer convex preheating bin 13 can be in close contact with the inner wall of the outer kiln 1 through the flexible layer 132, thereby ensuring that the inner wall of the outer kiln 2 and the outer wall of the outer convex preheating bin 13 form a spiral-shaped preheating channel 3, thereby guiding the high-temperature flue gas; The outer kiln 2 can be arranged in multiple according to the length of the production line, and the multiple outer kilns 2 are sequentially and coaxially arranged outside the inner kiln 1 along the length direction of the inner kiln 1; The protrusions 131 are fixedly arranged on the spiral ridge of the outer convex preheating bin 13.

[0036] The outer kiln 2 side wall is provided with a plurality of combustion openings 21 at the sintering space 4, the combustion openings 21 are connected with the combustion machine nozzle through the combustion pipe, the outer kiln 2 is provided with an air inlet 22 at one end of the preheating channel 3 and an air outlet 23 at the other end, the air inlet 22 is communicated with the sintering space 4 through the external pipeline 5, by setting a plurality of combustion openings 21 at the sintering space 4 and cooperating with the rotating inner kiln 1, the uniformity of the material during sintering is improved.

[0037] In the embodiment, the shape of the external pipeline 5 can be set according to the number of outer kilns 2, so that the high-temperature flue gas generated in each outer kiln 2 can enter the preheating channel 3 through the external pipeline 5 to complete the directional flow guiding and preheating of the material.

[0038] The pitch of the outer convex preheating bin 13 gradually decreases along the material conveying direction, the inner wall of the outer kiln 2 is provided with a heat insulation ring 24, the heat insulation ring 24 is sleeved outside the inner kiln 1 and located between the preheating pipe 11 and the sintering pipe 12, by setting the heat insulation ring 24 between the preheating pipe 11 and the sintering pipe 12, the high-temperature flue gas cannot flow horizontally from the sintering space 4 to the preheating channel 3, so that the high-temperature flue gas is guided in the preheating channel 3, the residence time of the high-temperature flue gas is prolonged, the efficiency of flue gas heat exchange is improved, and the uniformity of the preheated material is improved by reducing the pitch of the outer convex preheating bin 13 at the end of the preheating pipe 11.

[0039] The elastic cleaning strip 6 comprises a fixed seat 61 and a cleaning rod 63, one end of the fixed seat 61 is fixedly connected to the inner wall of the outer kiln 2, and the other end is fixedly connected with an elastic member 62, one end of the cleaning rod 63 is connected with the elastic member 62, and the other end extends to the outer wall of the outer convex preheating bin 13 and is in contact with the outer wall of the outer convex preheating bin 13, a rough layer 64 is arranged outside the cleaning rod 63 and used for scraping the accumulated dust on the outer part of the outer convex preheating bin 13, by setting the fixed seat 61 and the cleaning rod 63 and cooperating with the rotating inner kiln 1, the cleaning rod 63 can continuously scratch the dust on the surface of the outer convex preheating bin 13, so as to improve the heat exchange efficiency, and in cooperation with the protrusion 131, the outer convex preheating bin 13 is continuously impacted to avoid material caking.

[0040] In the embodiment, the elastic member 62 can be an elastic metal strip.

[0041] The rough layer 64 comprises: a flexible layer 641 coaxially fitted on the outside of the cleaning rod 63, and a plurality of ash scraping protrusions 642 fitted on the surface of the flexible layer 641 and spaced along the circumference of the flexible layer 641. By arranging the flexible layer 641, the flexible layer 641 can deform according to the surface shape of the outwardly convex preheating bin 13, so that the ash scraping protrusions 642 can always adhere to the outwardly convex preheating bin 13 according to the surface curvature of the outwardly convex preheating bin 13, thereby increasing the ash scraping area and improving the heat exchange efficiency between the high-temperature flue gas and the preheating pipe 11.

[0042] The second object of the present application is to provide a lithium iron phosphate sintering flue gas recycling system.

[0043] The technical scheme is as follows: a lithium iron phosphate sintering flue gas recycling system, comprising a lithium iron phosphate sintering kiln body, a feeding device 7, and a natural gas heat exchange device 8, wherein the inlet end of the natural gas heat exchange device 8 is connected with the gas outlet 23, the feeding device 7 comprises a pre-stirring assembly 71 which is hollow inside, the pre-stirring assembly 71 is communicated with the natural gas heat exchange device 8 through a connecting piece 74, and is used for stirring the material and preheating the material at the same time, the combustion machine is communicated with the natural gas pipe network through the natural gas heat exchange device 8, and the high-temperature flue gas generated at the sintering space 4 is sequentially introduced into the preheating channel 3, the natural gas heat exchange device 8, and the pre-stirring assembly 71, so that three heat exchanges are carried out by using the high-temperature flue gas, and the energy utilization rate of the whole system is improved.

[0044] The feeding device 7 further comprises a bin 72 and a weighing feeder 73, the pre-stirring assembly 71 is arranged inside the bin 72, a discharge pipe 721 is arranged at the lower end of the bin 72, a control valve is arranged on the discharge pipe 721, a driving piece is arranged above the bin 72, the driving piece is connected with the pre-stirring assembly 71 and is used for driving the pre-stirring assembly 71 to rotate, one end of the weighing feeder 73 is communicated with the discharge pipe 721, and the other end is communicated with the kiln 1, the pre-stirring assembly 71 which can continuously rotate and is hollow is arranged inside the bin 72, so that the pre-stirring assembly 71 can continuously stir the material inside the bin 72, and the material inside the bin 72 can be preheated by introducing flue gas with a temperature, thereby facilitating the subsequent faster heating and sintering of the material.

[0045] In the embodiment, the driving piece can be a rotary motor.

[0046] The pre-stirring assembly 71 comprises a stirring pipe 711 and stirring blades 712, one end of the stirring pipe 711 extends to the outside of the upper end of the bunker 72 and is connected with the driving shaft of the driving member, the other end of the stirring pipe 711 extends to the outside of the lower end of the bunker 72, both ends of the stirring pipe 711 are communicated with the connecting member 74, the stirring blades 712 are hollow inside and are coaxially connected with the stirring pipe 711, by arranging the stirring pipe 711 and the stirring blades 712 hollow inside, the stirring blades can uniformly preheat the materials in the bunker 72 when stirring the materials in the bunker 72.

[0047] The connecting member 74 comprises connecting rings 741 and connecting pipes 742, two connecting rings 741 are coaxially rotationally connected at both ends of the stirring pipe 711, the connecting rings 741 are internally provided with flow channels, two connecting pipes 742 are provided, one end of the two connecting pipes 742 is respectively communicated with both ends of the stirring pipe 711 through the two connecting rings 741, the other end of the two connecting pipes 742 is respectively communicated with the natural gas heat exchange device 8 and the tail gas treatment equipment, by arranging the connecting rings 741 rotationally connected with the stirring pipe 711, the device does not affect the rotation of the stirring pipe 711, and high-temperature flue gas can be introduced into the stirring blades, thereby preheating the materials in the bunker 72.

[0048] The natural gas heat exchange device 8 comprises a gas heat exchanger 81 and a gas pump 82, the inlet end of the gas heat exchanger 81 is communicated with the gas outlet 23 through the gas pump 82, the gas outlet end of the gas heat exchanger 81 is communicated with the other end of one of the connecting pipes 742, by arranging the gas heat exchanger 81 and the gas pump 82, the gas pump 82 provides power for the high-temperature flue gas flow in the whole system, so that the high-temperature flue gas can continuously flow and exchange heat in the whole system, thereby improving the heat utilization rate.

[0049] The above are the preferred embodiments of the present application, which do not limit the protection scope of the present application, therefore: any equivalent changes made on the structure, shape and principle of the present application shall be covered within the protection scope of the present application.

Claims

1. A kiln body for sintering lithium iron phosphate, characterized by, include: An inclined inner kiln (1) includes a preheating pipe (11) and a sintering pipe (12). The preheating pipe (11) and the sintering pipe (12) are arranged sequentially and connected along the material conveying direction. The preheating pipe (11) is provided with a spiral-shaped convex preheating chamber (13) outside. The convex preheating chamber (13) is hollow inside and connected to the inside of the preheating pipe (11). The outer wall of the convex preheating chamber (13) is provided with a plurality of protrusions (131) spaced apart along its own length direction. An outer kiln (2) is fitted outside the inner kiln (1). A rotating device connected to the inner kiln (1) is provided on one side of the outer kiln (2). A flexible layer (132) is provided on the outer edge of the protruding preheating chamber (13), and the flexible layer (132) is press-fitted with the inner wall of the outer kiln (2). A spiral preheating channel (3) is formed between the inner wall of the outer kiln (2) and the outer wall of the protruding preheating chamber (13). A tubular sintering tube (12) is formed between the inner wall of the outer kiln (2) and the outer wall of the sintering tube (12). The sintering space (4) is connected to the preheating channel (3) through an external pipe (5) to allow the flue gas generated during sintering to be introduced into the preheating channel (3) for material preheating. The inner wall of the outer kiln (2) is provided with multiple elastic cleaning strips (6) at intervals in the preheating channel (3). One end of the elastic cleaning strip (6) extends to contact the protruding preheating chamber (13), so that it undergoes elastic deformation under the contact with the protrusion (131) and intermittently impacts the protruding preheating chamber (13).

2. The kiln body for sintering lithium iron phosphate according to claim 1, characterized in that: The outer kiln (2) has multiple combustion ports (21) on its side wall in the sintering space (4). The combustion ports (21) are connected to the burner nozzles through combustion pipes. The outer kiln (2) has an air inlet (22) at one end of the preheating channel (3) and an air outlet (23) at the other end. The air inlet (22) is connected to the sintering space (4) through the external pipe (5).

3. The kiln body for sintering lithium iron phosphate according to claim 2, characterized in that: The pitch of the protruding preheating chamber (13) gradually decreases along the material conveying direction. The inner wall of the outer kiln (2) is provided with a heat insulation ring (24). The heat insulation ring (24) is sleeved outside the inner kiln (1) and located between the preheating pipe (11) and the sintering pipe (12).

4. The kiln body for sintering lithium iron phosphate according to claim 3, characterized in that, The elastic cleaning strip (6) includes: A fixed base (61) is fixedly connected at one end to the inner wall of the outer kiln (2) and at the other end to an elastic element (62); A cleaning rod (63) is connected at one end to the elastic element (62) and at the other end to the outer wall of the protruding preheating chamber (13) and in contact with the outer wall of the protruding preheating chamber (13). The cleaning rod (63) is provided with a rough layer (64) on the outside for scraping the dust accumulated on the outside of the protruding preheating chamber (13).

5. The kiln body for sintering lithium iron phosphate according to claim 4, characterized in that, The roughening layer (64) includes: A flexible layer (641) is coaxially mounted on the outside of the cleaning rod (63); The gray scraping protrusions (642) are provided with a plurality of gray scraping protrusions (642) assembled on the surface of the flexible layer (641) and spaced along the circumference of the flexible layer (641).

6. A lithium iron phosphate sintering exhaust gas recycling system characterized by comprising: The kiln body for sintering lithium iron phosphate includes the feeding device (7) and the natural gas heat exchange device (8) as claimed in any one of claims 1-5, the inlet end of the natural gas heat exchange device (8) is connected with the gas outlet (23), the feeding device (7) includes a pre-stirring assembly (71) with a hollow interior, the pre-stirring assembly (71) is communicated with the natural gas heat exchange device (8) through a connecting piece (74), which is used for stirring the material and preheating the material at the same time, and the combustion machine is communicated with the natural gas pipeline network through the natural gas heat exchange device (8).

7. The lithium iron phosphate sintering flue gas recycling system according to claim 6, characterized in that, The feeding device (7) further includes: a hopper (72), the pre-stirring assembly (71) is arranged in the hopper (72), a lower end of the hopper (72) is provided with a discharging pipe (721), the discharging pipe (721) is provided with a control valve, a driving member is arranged above the hopper (72), the driving member is connected with the pre-stirring assembly (71) and used for driving the pre-stirring assembly (71) to rotate; a weighing feeder (73), one end of the weighing feeder (73) is communicated with the discharging pipe (721), and the other end of the weighing feeder (73) is communicated with the kiln (1).

8. The lithium iron phosphate sintering flue gas recycling system according to claim 7, characterized in that, The pre-stirring assembly (71) includes: a stirring pipe (711), one end of the stirring pipe (711) extends to the outside of the upper end of the hopper (72) and is connected with the driving shaft of the driving member, the other end of the stirring pipe (711) extends to the outside of the lower end of the hopper (72), and both ends of the stirring pipe (711) are communicated with the connecting piece (74); a stirring blade (712), the stirring blade (712) is hollow and coaxially connected with the stirring pipe (711).

9. The lithium iron phosphate sintering flue gas recycling system according to claim 8, characterized in that, The connecting piece (74) includes: a connecting ring (741), two connecting rings (741) are coaxially and rotatably connected with both ends of the stirring pipe (711), and a flow passage is arranged in the connecting ring (741); a connecting pipe (742), two connecting pipes (742) are arranged, one end of each of the two connecting pipes (742) is communicated with both ends of the stirring pipe (711) through the two connecting rings (741), and the other end of each of the two connecting pipes (742) is communicated with the natural gas heat exchange device (8) and the tail gas treatment equipment.

10. The lithium iron phosphate sintering flue gas recycling system according to claim 9, characterized in that, The natural gas heat exchange device (8) includes a gas heat exchanger (81) and a gas pump (82), the inlet end of the gas heat exchanger (81) is communicated with the gas outlet (23) through the gas pump (82), and the gas outlet end of the gas heat exchanger (81) is communicated with the other end of one of the connecting pipes (742).

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