Heap leaching method for leaching of rare earth-containing acid leaching residue for rare earth recovery

Abstract

The present invention relates to the technical field of rare earth recovery. Disclosed is a heap leaching method for leaching of rare earth-containing acid leaching residue for rare earth recovery. The heap leaching method for leaching of rare earth-containing acid leaching residue for rare earth recovery is implemented by means of a heap leaching apparatus for leaching of rare earth-containing acid leaching residue for rare earth recovery. The heap leaching apparatus for leaching of rare earth-containing acid leaching residue for rare earth recovery comprises a treatment kettle, wherein the inside of the treatment kettle is provided with a driving mechanism, the outer side of the driving mechanism is provided with a blocking mechanism, a filtering and drying mechanism, and a sealing mechanism in sequence from top to bottom. The driving mechanism comprises a drive shaft, a drive electric motor, a negative-pressure liquid discharge pipe, a hot-air input pipe, a liquid discharge hole, an air intake hole, and a shift lever; the drive shaft penetrates the treatment kettle and is rotatably connected to the treatment kettle by means of a bearing. In the present invention, while a leaching solution is filtered, supernatant in the leaching solution can be synchronously drawn off from above, thereby effectively accelerating the filtering of the leaching solution, improving the rare earth recovery and extraction efficiency.

Description

A method for recovering rare earths by heap leaching rare earth-containing acid hydrolysis slag Technical Field

[0001] The invention relates to the technical field of rare earth recovery, in particular to a method for recovering rare earth by heap leaching rare earth-containing acid hydrolysis slag. Background Art

[0002] Rare earth elements exist mainly in the form of minerals in the earth's crust, a considerable portion of which coexists in apatite and phosphate rock. It is estimated that 250 million tons of phosphate rock are used for phosphoric acid production worldwide each year. The average rare earth element content in phosphate rock is 0.046%, so about 100,000 tons of rare earth elements eventually enter the phosphogypsum.

[0003] The invention patent with authorization publication number CN 110373549 B discloses a method for recovering rare earths from rare earth-containing acid hydrolysis residue by heap leaching. The method uses a Gluconobacter solution as the leaching solution to extract and recover rare earths from the rare earth-containing acid hydrolysis residue by heap leaching. This invention has the characteristics of being able to recover rare earth elements from the acid hydrolysis residue, and the extraction process is environmentally friendly. Technical issues

[0004] However, after actual application by technicians in this field, it was found that the above method still has some shortcomings. The most obvious one is that when filtering the extract after precipitation, since the supernatant occupies a larger part, the traditional method of filtration takes a long time, which has a great impact on the recovery and extraction efficiency of rare earths.

[0005] Therefore, it is necessary to invent a method for recovering rare earths by heap leaching rare earth-containing acid hydrolysis slag to solve the above problems. Technical Solutions

[0006] The object of the present invention is to provide a method for recovering rare earths by heap leaching rare earth-containing acid hydrolysis residues, so as to solve the problems raised in the above background technology.

[0007] To achieve the above object, the present invention provides the following technical solution: a method for recovering rare earths by heap leaching rare earth-containing acidolysis slag, wherein the method for recovering rare earths by heap leaching rare earth-containing acidolysis slag is achieved by using an apparatus for recovering rare earths by heap leaching rare earth-containing acidolysis slag, wherein the apparatus for recovering rare earths by heap leaching rare earth-containing acidolysis slag comprises a treatment kettle, wherein a driving mechanism is provided inside the treatment kettle, and a blocking mechanism, a filtering and drying mechanism, and a sealing mechanism are provided on the outside of the driving mechanism in order from top to bottom;

[0008] The driving mechanism includes a driving shaft, a driving motor, a negative pressure liquid discharge pipe, a hot air input pipe, a liquid discharge hole, an air inlet hole and a shift lever;

[0009] The drive shaft passes through the processing kettle and is rotatably connected to the processing kettle through a bearing. The drive motor is fixedly arranged on the top of the processing kettle and is transmission-connected to the drive shaft. The negative pressure drain pipe and the hot air input pipe are respectively connected to the top and bottom ends of the drive shaft through rotary joints. The drain hole and the air inlet hole are sequentially opened on the front face of the drive shaft from top to bottom, and the two shift rods are respectively fixedly arranged on both sides of the drive shaft.

[0010] Preferably, the blocking mechanism includes a top plate, a first spring, a connecting ring, a blocking tube and an avoidance channel.

[0011] Preferably, the top plate, the first spring, the connecting ring and the sealing tube are sequentially sleeved on the outside of the drive shaft from top to bottom, the top plate is fixedly connected to the drive shaft, one end of the first spring is fixedly connected to the top plate and the other end is fixedly connected to the connecting ring, the sealing tube is fixedly arranged on the inside of the connecting ring, the sealing tube is slidably connected to the drive shaft, and the avoidance channel is opened on the front of the sealing tube.

[0012] Preferably, the filtering and drying mechanism includes a filter plate, filter holes, a sealing cover, a driving groove, an avoidance groove, a heating scraper and a valve.

[0013] Preferably, the filter plate is sleeved on the outside of the drive shaft and is connected to the drive shaft through a reciprocating thread. The filter plate is slidably nested on the inside of the treatment kettle along the vertical direction. Multiple filter holes are evenly penetrated and arranged on the top of the filter plate. The sealing cover is slidably sleeved on the outside of the drive shaft and is rotatably arranged on the top of the filter plate through a bearing. The driving groove and the avoidance groove are sequentially opened on the inside of the sealing cover from top to bottom. Multiple heating scrapers are evenly fixed and nested on the bottom outside of the sealing cover, and multiple valves are respectively fixed and nested on the outside of the tops of multiple heating scrapers.

[0014] Preferably, the closing mechanism includes a closing plate, a second spring and a closing rod.

[0015] Preferably, the closing plate is slidably sleeved on the outside of the driving shaft and slidably nested inside the processing kettle along the vertical direction, the second spring is fixedly arranged at the bottom of the closing plate and fixedly connected to the inner wall of the processing kettle, and multiple closing rods are evenly fixed on the top of the closing plate.

[0016] Preferably, the method for recovering rare earths by heap leaching rare earth-containing acid hydrolysis slag specifically comprises the following steps:

[0017] S1, the leachate generated by the circulating leaching and acid hydrolysis slag powder pile is input into the processing kettle. The leachate accumulates on the top of the filter plate due to the obstruction of the filter plate and the sealing plate. Subsequently, an alkali solution and a precipitant for adjusting the pH value are added into the processing kettle, and precipitate is continuously generated in the leachate;

[0018] S2. After the sedimentation is complete, the drive motor is started. After the drive motor is started, the drive shaft is driven to rotate continuously. When the drive shaft rotates, the lever is driven to idle inside the avoidance groove, and the filter plate is driven to rise continuously. When the filter plate rises, the filter plate and the sealing plate form a filtrate transfer chamber, and the sealing rod is gradually moved out from the inside of the filter hole.

[0019] S3: When the filter plate rises to a first threshold, the sealing rod moves out from the inside of the filter hole. At this time, the extract on the top of the filter plate continuously passes through the filter hole and enters the filtrate transfer chamber, and is then discharged through the pipe in the middle of the right side of the treatment kettle;

[0020] S4: When the filter plate rises to a second threshold, the sealing cover fits against the blocking tube. As the filter plate continues to rise, the filter plate pushes the blocking tube through the sealing cover, causing the blocking tube to drive the avoidance channel and the connecting ring to rise synchronously. When the connecting ring rises, it compresses the first spring.

[0021] S5. When the filter plate rises to a third threshold, the avoidance channel is connected to the drainage hole, and the negative pressure transmitted to the inside of the drive shaft by the negative pressure drainage pipe is transmitted to the inside of the treatment kettle through the drainage hole and the avoidance channel, thereby continuously sucking the supernatant liquid in the leachate. The supernatant liquid is continuously discharged through the avoidance channel, the drainage hole, and the drive shaft through the negative pressure drainage pipe;

[0022] S6: When the filter plate reaches the fourth threshold, the filter plate moves to the top of the reciprocating thread on the outside of the drive shaft. As the drive shaft continues to rotate, the filter plate descends and resets. When the filter plate descends to the fifth threshold, the filter plate returns to the initial position. At this time, the sealing rod re-enters the inner side of the filter hole to achieve sealing.

[0023] S7. Subsequently, as the driving shaft continues to rotate, the filter plate drives the sealing plate to continue to descend. When the filter plate descends a distance reaching a sixth threshold, the air inlet moves relatively to the inside of the sealing cover, and the lever moves relatively to the inside of the driving groove. At this time, the driving shaft drives the sealing cover to rotate through the lever and the driving groove. When the sealing cover rotates, the heated scraper flips the sediment. The hot air input into the driving shaft by the hot air input pipe enters the sealing cover through the air inlet, and then enters the multiple heating scrapers to heat the heating scrapers respectively. Finally, the valve is opened and enters the processing kettle. The heated heating scrapers and the hot air entering the processing kettle heat the sediment synchronously, thereby achieving sediment drying.

[0024] S8, when the filter plate descends to the seventh threshold, the filter plate arrives at the discharge station. At this time, as the heated scraper continues to rotate, the dried sediment is continuously pushed by the heated scraper and then discharged through the pipe at the bottom left of the treatment kettle;

[0025] S9. When the filter plate descends to the eighth threshold, the discharge is completed and the filter plate moves to the bottom of the reciprocating thread on the outside of the drive shaft. Subsequently, as the drive shaft continues to rotate, the filter plate moves up and resets until it reaches the initial position and stops the drive motor. Beneficial effects

[0026] The technical effects and advantages of the present invention are as follows:

[0027] The present invention is provided with a driving mechanism, a blocking mechanism, a filtering and drying mechanism and a closing mechanism, so that the driving mechanism is used to drive the filtering and drying mechanism, and then the closing mechanism releases the blocking of the filtering and drying mechanism to realize the filtering of the leachate. Subsequently, as the driving mechanism is continuously driven, the filtering and drying mechanism triggers the blocking mechanism, and then the driving mechanism outputs the supernatant in the leachate while filtering the leachate. Subsequently, when the filtering and drying mechanism moves down and resets and continues to move down, the filtering and drying mechanism drives the closing mechanism to move down synchronously, and the driving mechanism drives the filtering and drying mechanism and inputs hot air, and then outputs the precipitate after drying. Compared with the same type of device in the prior art, the present invention can simultaneously extract the supernatant in the leachate from the top while filtering the leachate, thereby effectively accelerating the filtration speed of the leachate and improving the recovery and extraction efficiency of rare earths. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] FIG1 is a schematic diagram of the overall front cross-sectional structure of the present invention.

[0029] FIG2 is a schematic front cross-sectional structural diagram of the driving mechanism of the present invention.

[0030] FIG3 is a schematic diagram of the front cross-sectional structure of the blocking mechanism of the present invention.

[0031] FIG4 is a schematic diagram of the front cross-sectional structure of the filtering and drying mechanism of the present invention.

[0032] FIG5 is a schematic diagram of the front cross-sectional structure of the sealing mechanism of the present invention.

[0033] In the figure: 1. treatment kettle; 2. driving mechanism; 21. driving shaft; 22. driving motor; 23. negative pressure drain pipe; 24. hot air input pipe; 25. drain hole; 26. air inlet hole; 27. shift lever; 3. blocking mechanism; 31. top plate; 32. first spring; 33. connecting ring; 34. blocking pipe; 35. avoidance channel; 4. filtering and drying mechanism; 41. filter plate; 42. filter hole; 43. sealing cover; 44. driving groove; 45. avoidance groove; 46. heating scraper; 47. valve; 5. closing mechanism; 51. closing plate; 52. second spring; 53. closing rod. Modes for Carrying Out the Invention

[0034] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention. Example 1

[0035] The present invention provides a method for recovering rare earths by heap leaching rare earth-containing acidolysis slag as shown in Figures 1-5. The method for recovering rare earths by heap leaching rare earth-containing acidolysis slag is implemented by a device for recovering rare earths by heap leaching rare earth-containing acidolysis slag. The device for recovering rare earths by heap leaching rare earth-containing acidolysis slag includes a treatment kettle 1, a driving mechanism 2 is provided inside the treatment kettle 1, and a blocking mechanism 3, a filtering and drying mechanism 4, and a sealing mechanism 5 are provided on the outside of the driving mechanism 2 in order from top to bottom.

[0036] As shown in Figure 2, the driving mechanism 2 includes a driving shaft 21, a driving motor 22, a negative pressure drain pipe 23, a hot air input pipe 24, a drain hole 25, an air inlet hole 26 and a shift lever 27, wherein the driving shaft 21 passes through the processing kettle 1 and is rotatably connected to the processing kettle 1 through a bearing, the driving motor 22 is fixedly arranged on the top of the processing kettle 1 and is transmission-connected to the driving shaft 21, the negative pressure drain pipe 23 and the hot air input pipe 24 are respectively connected to the top and bottom ends of the driving shaft 21 through a rotary joint, the drain hole 25 and the air inlet hole 26 are sequentially opened on the front face of the driving shaft 21 from top to bottom, and the two shift levers 27 are respectively fixedly arranged on both sides of the driving shaft 21.

[0037] As shown in Figure 3, the sealing mechanism 3 includes a top plate 31, a first spring 32, a connecting ring 33, a sealing tube 34 and an avoidance channel 35, wherein the top plate 31, the first spring 32, the connecting ring 33 and the sealing tube 34 are sequentially sleeved on the outside of the drive shaft 21 from top to bottom, the top plate 31 is fixedly connected to the drive shaft 21, one end of the first spring 32 is fixedly connected to the top plate 31 and the other end is fixedly connected to the connecting ring 33, the sealing tube 34 is fixedly arranged on the inside of the connecting ring 33, the sealing tube 34 is slidably connected to the drive shaft 21, and the avoidance channel 35 is opened on the front of the sealing tube 34.

[0038] By setting the above structure, when the blocking tube 34 is pushed upward, the blocking tube 34 drives the avoidance channel 35 and the connecting ring 33 to rise synchronously. When the connecting ring 33 rises, the first spring 32 is compressed. As the avoidance channel 35 continues to move upward, the avoidance channel 35 is connected with the drainage hole 25. The negative pressure transmitted to the inside of the drive shaft 21 by the negative pressure drainage pipe 23 is transmitted to the inside of the processing kettle 1 through the drainage hole 25 and the avoidance channel 35, thereby continuously sucking the upper clear liquid in the extract, and the upper clear liquid is continuously discharged through the negative pressure drainage pipe 23 through the avoidance channel 35, the drainage hole 25 and the drive shaft 21.

[0039] As shown in Figure 4, the filtering and drying mechanism 4 includes a filter plate 41, a filter hole 42, a sealing cover 43, a drive groove 44, an avoidance groove 45, a heating scraper 46 and a valve 47, wherein the filter plate 41 is sleeved on the outside of the drive shaft 21 and is transmission-connected to the drive shaft 21 through a reciprocating thread, the filter plate 41 is slidably nested on the inside of the treatment kettle 1 along the vertical direction, a plurality of the filter holes 42 are evenly penetrated and arranged on the top of the filter plate 41, the sealing cover 43 is slidably sleeved on the outside of the drive shaft 21 and is rotatably arranged on the top of the filter plate 41 through a bearing, the driving groove 44 and the avoidance groove 45 are sequentially opened on the inside of the sealing cover 43 from top to bottom, a plurality of the heating scrapers 46 are evenly and fixedly nested on the bottom outside of the sealing cover 43, and a plurality of the valves 47 are respectively fixedly nested on the outside of the tops of the plurality of heating scrapers 46.

[0040] By setting up the above structure, the driving motor 22 drives the driving shaft 21 to rotate continuously after it is started. When the driving shaft 21 rotates, it drives the lever 27 to idle inside the avoidance groove 45, and at the same time drives the filter plate 41 to continuously rise. When the filter plate 41 rises, the extract on the top of the filter plate 41 continuously passes through the filter hole 42 and enters the filtrate transfer chamber, and is then output through the pipeline in the middle of the right side of the treatment kettle 1.

[0041] As shown in Figure 5, the closing mechanism 5 includes a closing plate 51, a second spring 52 and a closing rod 53, wherein the closing plate 51 is slidably sleeved on the outside of the driving shaft 21 and slidably nested in the processing kettle 1 along the vertical direction, the second spring 52 is fixedly arranged at the bottom of the closing plate 51 and fixedly connected to the inner wall of the processing kettle 1, and multiple closing rods 53 are evenly fixed on the top of the closing plate 51.

[0042] By setting up the above structure, the filter holes 42 in the filter plate 41 can be blocked by the closing rod 53, thereby preventing the unprecipitated extract from being output through the filter holes 42. At the same time, the closing plate 51 can block the air inlet hole 26, thereby preventing the hot air input into the drive shaft 21 by the hot air input pipe 24 from overflowing through the air inlet hole 26. Example 2

[0043] The method for recovering rare earths by heap leaching rare earth-containing acid hydrolysis slag specifically comprises the following steps:

[0044] S1, the leachate generated by the circulating leaching and acid decomposition slag powder pile is input into the processing kettle 1. The leachate accumulates on the top of the filter plate 41 due to the obstruction of the filter plate 41 and the sealing plate 51. Subsequently, an alkali solution and a precipitant for adjusting the pH value are added into the processing kettle 1, and precipitate is continuously generated in the leachate;

[0045] S2. After the sedimentation is complete, the drive motor 22 is started. After the drive motor 22 is started, the drive shaft 21 is driven to rotate continuously. When the drive shaft 21 rotates, the lever 27 is driven to idle inside the avoidance groove 45, and the filter plate 41 is driven to continuously rise. When the filter plate 41 rises, the filter plate 41 and the sealing plate 51 form a filtrate transfer chamber, and the sealing rod 53 is gradually moved out from the inside of the filter hole 42.

[0046] S3: When the filter plate 41 rises to a first threshold, the sealing rod 53 moves out from the inside of the filter hole 42. At this time, the extract on the top of the filter plate 41 continuously passes through the filter hole 42 and enters the filtrate transfer chamber, and is then discharged through the pipeline in the middle of the right side of the treatment kettle 1.

[0047] S4: When the filter plate 41 rises to a second threshold, the sealing cover 43 fits against the blocking tube 34. As the filter plate 41 continues to rise, the filter plate 41 pushes the blocking tube 34 through the sealing cover 43, causing the blocking tube 34 to drive the avoidance channel 35 and the connecting ring 33 to rise synchronously. When the connecting ring 33 rises, it compresses the first spring 32.

[0048] S5, when the filter plate 41 rises to a third threshold, the avoidance channel 35 is connected to the drainage hole 25, and the negative pressure transmitted to the inside of the drive shaft 21 by the negative pressure drainage pipe 23 is transmitted to the inside of the processing kettle 1 through the drainage hole 25 and the avoidance channel 35, thereby continuously sucking the supernatant in the leachate. The supernatant is continuously discharged through the avoidance channel 35, the drainage hole 25 and the drive shaft 21 through the negative pressure drainage pipe 23;

[0049] S6: When the filter plate 41 reaches the fourth threshold value, the filter plate 41 moves to the top of the reciprocating thread on the outside of the drive shaft 21. As the drive shaft 21 continues to rotate, the filter plate 41 descends and resets. When the filter plate 41 reaches the fifth threshold value, the filter plate 41 arrives at the initial position. At this time, the sealing rod 53 re-enters the inner side of the filter hole 42 to seal the filter hole 42.

[0050] S7. Subsequently, as the driving shaft 21 continues to rotate, the filter plate 41 drives the closing plate 51 to continue to descend. When the descending distance of the filter plate 41 reaches the sixth threshold, the air inlet 26 moves relatively to the inside of the sealing cover 43, and the lever 27 moves relatively to the inside of the driving groove 44. At this time, the driving shaft 21 drives the sealing cover 43 to rotate through the lever 27 and the driving groove 44. When the sealing cover 43 rotates, the heated scraper 46 turns the sediment. The hot air input from the hot air input pipe 24 to the inside of the driving shaft 21 enters the inside of the sealing cover 43 through the air inlet 26, and then enters the multiple heating scrapers 46 respectively to heat the heating scrapers 46, and finally opens the valve 47 to enter the inside of the processing kettle 1. The heated heating scrapers 46 and the hot air entering the inside of the processing kettle 1 heat the sediment synchronously, thereby achieving the drying of the sediment.

[0051] S8, when the filter plate 41 descends to the seventh threshold, the filter plate 41 arrives at the discharge station. At this time, as the heated scraper 46 continues to rotate, the dried precipitate is continuously pushed by the heated scraper 46 and then discharged through the pipe at the bottom left of the processing kettle 1;

[0052] S9. When the filter plate 41 descends to the eighth threshold, the discharge is completed, and the filter plate 41 moves to the bottom of the reciprocating thread on the outside of the drive shaft 21. Subsequently, as the drive shaft 21 continues to rotate, the filter plate 41 moves up and resets until it reaches the initial position and stops the drive motor 22.

[0053] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for recovering rare earths by heap leaching rare earth-containing acid hydrolysis slag, characterized in that: The method for recovering rare earths by heap leaching rare earth-containing acid hydrolysis slag is realized by a device for recovering rare earths by heap leaching rare earth-containing acid hydrolysis slag. The device for recovering rare earths by heap leaching rare earth-containing acid hydrolysis slag comprises a treatment kettle (1), a driving mechanism (2) is arranged inside the treatment kettle (1), and a blocking mechanism (3), a filtering and drying mechanism (4) and a sealing mechanism (5) are arranged on the outside of the driving mechanism (2) in order from top to bottom; The driving mechanism (2) comprises a driving shaft (21), a driving motor (22), a negative pressure liquid discharge pipe (23), a hot air input pipe (24), a liquid discharge hole (25), an air inlet hole (26) and a lever (27); The driving shaft (21) passes through the processing kettle (1) and is rotatably connected to the processing kettle (1) via a bearing; the driving motor (22) is fixedly arranged at the top of the processing kettle (1) and is transmission-connected to the driving shaft (21); the negative pressure liquid discharge pipe (23) and the hot air input pipe (24) are respectively connected to the top and bottom of the driving shaft (21) via a rotating joint; the liquid discharge hole (25) and the air inlet hole (26) are sequentially opened on the front side of the driving shaft (21) from top to bottom; and the two shifting rods (27) are respectively fixedly arranged on both sides of the driving shaft (21).

2. The method for recovering rare earths by heap leaching rare earth-containing acid hydrolysis slag according to claim 1, characterized in that: The blocking mechanism (3) comprises a top plate (31), a first spring (32), a connecting ring (33), a blocking tube (34) and an avoidance channel (35).

3. The method for recovering rare earths by heap leaching rare earth-containing acid hydrolysis slag according to claim 2, characterized in that: The top plate (31), the first spring (32), the connecting ring (33) and the blocking tube (34) are sequentially sleeved and arranged on the outside of the driving shaft (21) from top to bottom; the top plate (31) is fixedly connected to the driving shaft (21); one end of the first spring (32) is fixedly connected to the top plate (31) and the other end is fixedly connected to the connecting ring (33); the blocking tube (34) is fixedly arranged on the inside of the connecting ring (33); the blocking tube (34) is slidably connected to the driving shaft (21); and the avoidance channel (35) is opened on the front side of the blocking tube (34).

4. The method for recovering rare earths by heap leaching rare earth-containing acid hydrolysis slag according to claim 3, characterized in that: The filtering and drying mechanism (4) comprises a filter plate (41), filter holes (42), a sealing cover (43), a driving groove (44), an avoidance groove (45), a heating scraper (46) and a valve (47).

5. The method for recovering rare earths by heap leaching rare earth-containing acid hydrolysis slag according to claim 4, characterized in that: The filter plate (41) is sleeved and arranged on the outside of the drive shaft (21) and is transmission-connected to the drive shaft (21) via a reciprocating thread; the filter plate (41) is slidably nested and arranged on the inside of the processing kettle (1) along the vertical direction; a plurality of filter holes (42) are evenly arranged through the top of the filter plate (41); the sealing cover (43) is slidably sleeved and arranged on the outside of the drive shaft (21) and is rotationally arranged on the top of the filter plate (41) via a bearing; the driving groove (44) and the avoidance groove (45) are sequentially opened on the inside of the sealing cover (43) from top to bottom; a plurality of heating scrapers (46) are evenly fixedly nested and arranged on the bottom outside of the sealing cover (43); and a plurality of valves (47) are respectively fixedly nested and arranged on the outside of the tops of the plurality of heating scrapers (46).

6. The method for recovering rare earths by heap leaching rare earth-containing acid hydrolysis slag according to claim 5, characterized in that: The closing mechanism (5) comprises a closing plate (51), a second spring (52) and a closing rod (53).

7. The method for recovering rare earths by heap leaching rare earth-containing acid hydrolysis slag according to claim 6, characterized in that: The closing plate (51) is slidably sleeved on the outside of the driving shaft (21) and is slidably nested in the processing kettle (1) in the vertical direction; the second spring (52) is fixedly arranged at the bottom of the closing plate (51) and is fixedly connected to the inner wall of the processing kettle (1); and a plurality of closing rods (53) are evenly fixedly arranged on the top of the closing plate (51).

8. The method for recovering rare earths by heap leaching rare earth-containing acid hydrolysis slag according to claim 7, characterized in that: The method for recovering rare earths by heap leaching rare earth-containing acid hydrolysis slag specifically comprises the following steps: S1, inputting the leaching liquid generated by the circulating leaching and acid-lysing slag powder pile into the processing kettle (1), the leaching liquid is blocked by the filter plate (41) and the sealing plate (51) and accumulates on the top of the filter plate (41), and then adding an alkali solution and a precipitant for adjusting the pH value into the processing kettle (1), and precipitates are continuously generated in the leaching liquid; S2, after the sedimentation is complete, the driving motor (22) is started. After the driving motor (22) is started, the driving shaft (21) is driven to rotate continuously. When the driving shaft (21) rotates, the lever (27) is driven to rotate idly inside the avoidance groove (45), and the filter plate (41) is driven to continuously rise. When the filter plate (41) rises, the filter plate (41) and the sealing plate (51) form a filtrate transfer chamber, and the sealing rod (53) is gradually moved out from the inside of the filter hole (42); S3, when the filter plate (41) rises to a first threshold, the sealing rod (53) moves out from the inner side of the filter hole (42), and the extract on the top of the filter plate (41) continuously passes through the filter hole (42) and enters the filtrate transfer chamber, and is then discharged through the pipeline in the middle of the right side of the processing kettle (1); S4, when the filter plate (41) rises to a second threshold, the sealing cover (43) fits against the blocking tube (34), and as the filter plate (41) continues to rise, the filter plate (41) pushes the blocking tube (34) through the sealing cover (43), thereby causing the blocking tube (34) to drive the avoidance channel (35) and the connecting ring (33) to rise synchronously, and the connecting ring (33) compresses the first spring (32) when rising; S5, when the filter plate (41) rises to a third threshold, the avoidance channel (35) is connected to the drainage hole (25), and the negative pressure transmitted to the inside of the driving shaft (21) by the negative pressure drainage pipe (23) is transmitted to the inside of the processing kettle (1) through the drainage hole (25) and the avoidance channel (35), thereby continuously sucking the upper clear liquid in the leaching liquid, and the upper clear liquid is continuously discharged through the avoidance channel (35), the drainage hole (25) and the driving shaft (21) through the negative pressure drainage pipe (23); S6, when the filter plate (41) rises to a fourth threshold value, the filter plate (41) moves to the top of the reciprocating thread on the outside of the drive shaft (21), and then as the drive shaft (21) continues to rotate, the filter plate (41) descends and resets. When the filter plate (41) descends to a fifth threshold value, the filter plate (41) reaches the initial position, and at this time, the closing rod (53) enters the inside of the filter hole (42) again to achieve closing. S7. Subsequently, as the driving shaft (21) continues to rotate, the filter plate (41) drives the sealing plate (51) to continue to descend. When the descending distance of the filter plate (41) reaches a sixth threshold, the air inlet hole (26) moves relatively to the inside of the sealing cover (43), and at the same time, the lever (27) moves relatively to the inside of the driving groove (44). At this time, the driving shaft (21) drives the sealing cover (43) to rotate through the lever (27) and the driving groove (44). When the sealing cover (43) rotates, the heated scraper (46) The precipitate is turned over, and the hot air input into the driving shaft (21) through the hot air input pipe (24) enters the sealing cover (43) through the air inlet hole (26), and then enters the plurality of heating scrapers (46) to heat the heating scrapers (46), and finally opens the valve (47) to enter the processing kettle (1). The heated heating scrapers (46) and the hot air entering the processing kettle (1) heat the precipitate synchronously, thereby achieving drying of the precipitate; S8, when the filter plate (41) descends to a seventh threshold, the filter plate (41) arrives at the discharge station. At this time, as the heated scraper (46) continues to rotate, the dried precipitate is continuously pushed by the heated scraper (46) and then discharged through the pipeline at the bottom left side of the processing kettle (1); S9: When the filter plate (41) descends to a distance that reaches an eighth threshold value, the discharge is completed, and the filter plate (41) simultaneously moves to the bottom end of the reciprocating thread on the outside of the drive shaft (21). Subsequently, as the drive shaft (21) continues to rotate, the filter plate (41) moves upward and resets until it reaches the initial position, at which time the drive motor (22) is stopped.

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