Method and system for recovering rare earth elements from china clay ore resources

Abstract

The invention discloses a method and a system for recovering rare earth elements from china clay ore resources, the recovery process comprises the following steps: stirring petuntse into slurry through a stirring barrel, and then carrying out filter pressing on the petuntse through a first filter press, ammonium sulfate, washing water and compressed air are sequentially pumped into the petuntse at high pressure, so that tail liquid and petuntse waste materials can be blown out in a high-pressure state, then the tail liquid and the petuntse waste materials sequentially pass through a clarification tank, an impurity removal tank and a sedimentation tank and are subjected to solid-liquid layering, obtained solid parts are subjected to filter pressing through a second filter press, and rare earth products are obtained. The method is efficient and rapid, operation is simplified and programmed, the overall production cost is reduced, and the overall technological method is reliable and practical.

Description

Technical Field

[0001] The present invention relates to the field of rare earth technology, and in particular to a method for recovering rare earth elements from porcelain clay ore resources and a recovery system thereof. Background Art

[0002] In the existing market, most of the porcelain clay produced has low whiteness and low market value. In order to solve the problems existing in the current production line, it is planned to transform and upgrade the existing production line, further deepen the treatment of the porcelain clay produced by the existing production line, and improve the product quality; according to analysis, the main factors affecting the whiteness of porcelain clay are iron and a small amount of rare elements in the porcelain clay, among which iron is mainly iron oxide and part of impregnated iron, and rare elements are mainly ionic rare metal elements. According to the properties of metal elements in porcelain clay, it is planned to design a porcelain clay deepening treatment process of first removing rare elements and then removing iron; at the same time, through the deepening treatment of porcelain clay, it is found that some porcelain clay treatment tail liquid contains trace amounts of recoverable rare earth valuable elements. According to the content of valuable elements in the tail liquid, a design is designed to recover the rare earth elements in the tail liquid. Announcement No. CN112088224B, a method for precipitating rare earth sulfate, the method comprises: precipitating a crude rare earth sulfate solution in the presence of a water-soluble volatile organic compound to produce a rare earth sulfate precipitate and an acidic supernatant. The organic compound is preferably selected from the group consisting of methanol, ethanol, isopropanol, tert-butyl alcohol, acetone or a mixture thereof, and is preferably methanol. Preferably, during precipitation, the organic compound and the crude sulfate solution are used in a weight ratio of 0.25:1 to 1.5:1, preferably 0.5: to 1.25:1. However, this recovery method is costly and is not suitable for large-scale recovery. Summary of the invention

[0003] In view of the deficiencies of the prior art, the object of the present invention is to provide a low-cost and practical rare earth recovery process and recovery system thereof.

[0004] To achieve the above-mentioned purpose, the solution provided by the present invention is: a system for recovering rare earth elements from porcelain clay mineral resources, comprising a clarifier, a first filter press, a second filter press, a third filter press, a fourth filter press, a first feeder, a second feeder, a de-impurity tank, a sedimentation tank, and a regeneration tank, wherein the clarifier is provided with a first liquid outlet and a first discharge port, the first liquid outlet is connected to the de-impurity tank, and the first discharge port is connected to the first filter press; the de-impurity tank is provided with a second liquid outlet and a second discharge port, the second liquid outlet is connected to the sedimentation tank, the sedimentation tank is provided with a third liquid outlet and a third discharge port, the third discharge port is connected to the second filter press, the second filter press is provided with a fourth liquid outlet and a fourth discharge port, the third liquid outlet and the fourth liquid outlet are respectively connected to the regeneration tank, wherein the first feeder is used to feed ammonium carbonate into the de-impurity tank, and the second feeder is used to feed ammonium carbonate into the sedimentation tank.

[0005] Furthermore, it also includes a stirring barrel, the stirring barrel is connected to the first filter press, the first filter press is provided with a fifth liquid outlet and a fifth discharge port, and the fifth liquid outlet is connected to the clarification tank.

[0006] Furthermore, it also includes a third feeder, which is used to feed ammonium sulfate into the regeneration pool. After the present invention adopts the above structure, the leaching solution is formed and can be re-transported to the stirring barrel for reuse.

[0007] Furthermore, a reflux pipe is connected between the regeneration tank and the stirring barrel.

[0008] Furthermore, the first filter press comprises a first frame, two first sliding guides, a plurality of first filter bags, a first propulsion hydraulic cylinder, a plurality of first air film hoses, and a plurality of second air film hoses. The two first sliding guides are respectively arranged horizontally on the first frame, and the plurality of first filter bags slide on the first sliding guides respectively. The plurality of first filter bags are arranged at equal intervals along the length direction of the sliding guides. The first propulsion hydraulic cylinder is connected to the first filter bag at the front end, and the first filter bag at the rear end is connected to the first frame. The first filter bags are respectively connected to a first air film hose and a second air film hose. After the present invention adopts the above structure, the first propulsion hydraulic cylinder pushes the plurality of first filter bags to be compressed to achieve filtration.

[0009] Furthermore, the first filter press bag located at the rear end is connected to a forward feed port, and the first filter press bag located at the front end is connected to a reverse feed port.

[0010] Furthermore, it also includes a medicine water tank, a medicine feeding pipeline, a forward feeding pipeline, a reverse feeding pipeline, an air blowing pipeline, and a back blowing pipeline, wherein the medicine water tank is connected to the medicine feeding pipeline, the medicine feeding pipeline is respectively connected to a plurality of first air film hoses and a plurality of second air film hoses, the forward feeding pipeline is respectively connected to the forward feeding port and the reverse feeding pipeline, the reverse feeding pipeline is connected to the reverse feeding port, the main gas source is connected to the back blowing pipeline, the back blowing pipeline is respectively connected to the reverse feeding pipeline and the air blowing pipeline, and the air blowing pipeline is connected to the medicine feeding pipeline. After the present invention adopts the above structure, high-pressure gas is used to inject ammonium sulfate into porcelain mud in a filter press state.

[0011] Furthermore, the forward feed pipe is connected to a discharge pipe.

[0012] Furthermore, the first frame is provided with a water tank, which is located directly below the plurality of first filter press bags, wherein the bottoms of two of the first filter press bags are respectively provided with fifth liquid outlets, the fifth liquid outlets are downwardly directed toward the water tank, and the water tank is connected to the clarification tank.

[0013] Furthermore, the second filter press, the third filter press, and the fourth filter press all include a second frame, two second sliding guides, a plurality of second filter bags, and a second propulsion hydraulic cylinder. The two second sliding guides are respectively arranged horizontally on the second frame, and the plurality of second filter bags slide on the second sliding guides respectively. The plurality of second filter bags are arranged at equal intervals along the length direction of the second sliding guides. The second propulsion hydraulic cylinder is connected to the second filter bag at the front end, and the second filter bag at the rear end is connected to the second frame. After the present invention adopts the above structure, the second propulsion hydraulic cylinder pushes the plurality of second filter bags to be compressed to achieve filtration.

[0014] Furthermore, second sliding frames are respectively arranged on the left and right sides of the second filter press bag, and the second sliding frames slide on second sliding guide rails.

[0015] Furthermore, the second filter press bag located at the rear end is connected to a drain pipe, a switch valve is provided on the drain pipe, and a fourth liquid outlet is formed in the drain pipe.

[0016] The present invention also includes a method for recovering rare earth elements from porcelain clay mineral resources, comprising the following steps: S1. Add the porcelain mud into a mixing barrel and stir until the porcelain mud is stirred into a slurry, and then pour the slurry into the first filter press for filtration until the water content of the porcelain mud is 25 to 30%; S2. Keep the first filter press at the set pressure value and keep the ammonium sulfate, wash water and compressed air pumped into the first filter press in turn until the rare earth leachate, wash water and clay products are blown out; S3. The collected rare earth leachate and wash water are transported to a clarifier and allowed to stand until solid-liquid separation; the qualified rare earth leachate in the clarifier is then transported to the impurity removal tank, and the solid portion is mixed with the porcelain mud slurry in the stirring barrel in step S1; S4. A qualified ammonium bicarbonate solution is quantitatively added to the impurity removal tank through a first feeder, and the solution is stirred and the pH value is controlled to remove impurities; then the solution is allowed to stand until solid-liquid separation, and the impurity-removing rare earth leachate is transported to a sedimentation tank, and the solid portion is discharged; S5. quantitatively add a qualified ammonium bicarbonate solution precipitant into the sedimentation tank through the second feeder, fully stir the rare earth elements to form rare earth carbonate precipitation, let it stand until the solid and liquid are separated, and then transport the rare earth precipitation mother liquor to the regeneration tank, and use a mud pump to send the precipitated rare earth carbonate slurry part to the second filter press for solid-liquid separation; the rare earth precipitation mother liquor after filter pressing is transported to the regeneration tank, and the solid part is the rare earth carbonate product; S6. quantitatively add ammonium sulfate solid to the regeneration tank through the third feeder, stir and dissolve, and then stand and stratify, and the liquid part will be regenerated into ammonium sulfate leaching agent.

[0017] The invention has the following beneficial effects: reducing production cost and effectively extracting rare earth products. The recycling process firstly stirs porcelain mud to make pulp through a stirring barrel, and then filters the porcelain mud through a first filter press. The first filter press only performs one filter press, and under the filter press state of maintaining a set pressure value, ammonium sulfate, washing water and compressed air are sequentially pumped into the porcelain mud at high pressure, so that tail liquid and porcelain mud waste can be blown out under high pressure, and then pass through a clarification tank, a de-impurity tank and a sedimentation tank in sequence. After solid-liquid stratification, the obtained solid part is filtered through a second filter press to obtain a rare earth product. In this way, the extraction of ionic rare earth elements can be completed in the process of opening the filter press only once. The process is efficient and fast, the operation is simplified and programmed, the overall production cost is reduced, and the overall process technology method is reliable and practical. At the same time, materials such as rare earth leaching liquid and washing water are sent to processes and facilities such as clarification tanks, de-impurity tanks and sedimentation tanks for clarification, de-impurity, rare earth carbonate precipitation and other process treatments, and the rare earth carbonate precipitate is filtered through the second filter press to obtain a rare earth carbonate product.

[0018] Furthermore, the porcelain mud product after the filter pressing in step S2 is poured into a stirring tank for stirring, slurrying and washing.

[0019] Furthermore, the pressure value in step S2 is set to 6-8 MPa.

[0020] Furthermore, the stirred and washed porcelain mud product is poured into a third filter press for filtration, and the rare earth element-removed porcelain mud and washing water are obtained by filtration.

[0021] Furthermore, the washing water is transported to the sedimentation tank, and the porcelain mud with rare earth elements removed is poured into the stirring tank for stirring and slurrying, and then the iron is removed by magnetic separation in the magnetic separator in turn; and then the mud is respectively pumped into the fourth filter press for filtration to obtain high white porcelain mud and iron-containing porcelain mud. After the present invention adopts the above structure, high white porcelain mud and iron-containing porcelain mud can be screened out. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is the overall structural principle diagram of the present invention.

[0023] Figure 2 It is the principle diagram of the first filter press of the present invention.

[0024] Figure 3 The second filter press, the third filter press, and the fourth filter press of the present invention are three-dimensional Figure 1 .

[0025] Figure 4 The second filter press, the third filter press, and the fourth filter press of the present invention are three-dimensional Figure 2 .

[0026] Among them, 1 is a clarification tank, 11 is a first liquid outlet, 12 is a second liquid outlet, 21 is a first filter press, 211 is a forward feed port, 212 is a reverse feed port, 22 is a first frame, 221 is a first air film hose, 222 is a second air film hose, 231 is a first sliding frame, 23 is a first sliding guide rail, 24 is a first filter bag, 241 is a fifth liquid outlet, 25 is a first propulsion hydraulic cylinder, 26 is a medicine tank, 261 is a medicine feed pipeline, 271 is a forward feed pipeline, 272 is a reverse feed pipeline, 273 is a discharge pipeline, 281 is an air blowing pipeline, 282 is a back blowing pipeline, 29 is a water tank, 3 1 is the first feeder, 32 is the second feeder, 33 is the third feeder, 4 is the impurity removal tank, 41 is the second liquid outlet, 42 is the second liquid outlet, 6 is the sedimentation tank, 61 is the third liquid outlet, 62 is the third liquid outlet, 64 is the second filter press, 641 is the fourth liquid outlet, 65 is the second frame, 66 is the second sliding guide rail, 67 is the second filter bag, 671 is the second sliding frame, 68 is the second propulsion hydraulic cylinder, 691 is the drain pipe, 692 is the switch valve, 7 is the regeneration tank, 71 is the reflux pipe, 8 is the stirring barrel, 91 is the stirring tank, 92 is the third filter press, 93 is the magnetic separator, and 94 is the fourth filter press. DETAILED DESCRIPTION

[0027] The present invention will be further described below in conjunction with specific embodiments: Embodiment 1

[0028] See attached Figure 1 To Attachment Figure 4 As shown, a system for recovering rare earth elements from porcelain clay resources includes a clarifier 1, a first filter press 21, a medicine tank 26, a medicine feed pipe 261, a forward feed pipe 271, a reverse feed pipe 272, an air blowing pipe 281, a back-blowing pipe 282, a second filter press 64, a third filter press 92, a fourth filter press 94, a first feeder 31, a second feeder 32, a third feeder 33, a de-impurity tank 4, a sedimentation tank 6, a regeneration tank 7, a stirring barrel 8, two stirring tanks 91, a third filter press 92, a magnetic separator 93, and two fourth filter presses 94. The clarifier 1 is provided with a first liquid outlet 11 and a first discharge port 12. The first liquid outlet 11 is connected to the de-impurity tank 4, and the first discharge port 12 is connected to the first filter press 21.

[0029] The stirring barrel 8 is connected to the liquid inlet of the first filter press 21, and a reflux pipe 71 is connected between the regeneration tank 7 and the stirring barrel 8 to reflux the solution in the regeneration tank 7 to the stirring barrel 8. The impurity removal tank 4 is provided with a second liquid outlet 41 and a second discharge port 42, and the second liquid outlet 41 is connected to the sedimentation tank 6. The sedimentation tank 6 is provided with a third liquid outlet 61 and a third discharge port 62, and the third discharge port 62 is connected to the second filter press 64. The second filter press 64 is provided with a fourth liquid outlet 641 and a fourth discharge port, and the third liquid outlet 61 and the fourth liquid outlet 641 are respectively connected to the regeneration tank 7, wherein the first feeder 31 is used to feed ammonium carbonate into the impurity removal tank 4, the second feeder 32 is used to feed ammonium carbonate into the sedimentation tank 6, and the third feeder 33 is used to feed ammonium sulfate into the regeneration tank 7. A stirring tank 91 is connected to a third filter press 92, the third filter press 92 is connected to another stirring tank 91, another stirring tank 91 is connected to a magnetic separator 93, and the magnetic separator 93 is respectively connected to two fourth filter presses 94 In this embodiment, the first filter press 21 includes a first frame 22, two first sliding guides 23, a plurality of first filter bags 24, a first propulsion hydraulic cylinder 25, a plurality of first air film hoses 221, and a plurality of second air film hoses 222. The two first sliding guides 23 are respectively arranged on the first frame 22 in a horizontal direction. The plurality of first filter bags 24 slide on the first sliding guides 23, respectively. The plurality of first filter bags 24 are arranged at equal intervals along the length direction of the sliding guides. The first propulsion hydraulic cylinder 25 connects the first filter bag 24 at the front end, and the first filter bag 24 at the rear end is connected to the first frame 22. A first filter bag 24 is respectively connected to a first air film hose 221 and a second air film hose 222. In this embodiment, the first filter bag 24 at the rear end is connected to a forward feed port 211, and the first filter bag 24 at the front end is connected to a reverse feed port 212.

[0030] In this embodiment, the medicine tank 26 is connected to the medicine feed pipeline 261, the medicine feed pipeline 261 is respectively connected to multiple first air film hoses 221 and multiple second air film hoses 222, the forward feed pipeline 271 is respectively connected to the forward feed port 211 and the reverse feed pipeline 272, the reverse feed pipeline 272 is connected to the reverse feed port 212, the main air source is connected to the backflush pipeline 282, the backflush pipeline 282 is respectively connected to the reverse feed pipeline 272 and the blowing pipeline 281, and the blowing pipeline 281 is connected to the medicine feed pipeline 261.

[0031] In this embodiment, an air film valve is provided on the air blowing pipeline 281 , a medicine injection valve is provided on the medicine liquid pipeline 261 , and a check valve is provided on the back-blowing pipeline 282 .

[0032] In this embodiment, the first frame 22 is provided with a water tank 29, and the water tank 29 is located directly below the multiple first filter press bags 24, wherein the bottoms of two first filter press bags 24 are respectively provided with fifth liquid outlets 241, and the fifth liquid outlets 241 are downwardly aligned with the water tank 29, and the water tank 29 is connected to the clarification tank 1.

[0033] In this embodiment, the second filter press 64, the third filter press 92, and the fourth filter press 94 all include a second frame 65, two second sliding guides 66, a plurality of second filter bags 67, and a second propulsion hydraulic cylinder 68. The two second sliding guides 66 are respectively arranged on the second frame 65 in a horizontal direction. The plurality of second filter bags 67 slide on the second sliding guides 66, and the plurality of second filter bags 67 are arranged at equal intervals along the length direction of the second sliding guides 66. The second propulsion hydraulic cylinder 68 connects the second filter bag 67 at the front end, and the second filter bag 67 at the rear end is connected to the second frame 65. In this embodiment, the second filter bag 67 is respectively provided with a second sliding frame 671 on the left and right sides, and the second sliding frame 671 slides on the second sliding guides 66. In this embodiment, the second filter bag 67 at the rear end is connected with a drain pipe 691, and a switch valve 692 is provided on the drain pipe 691, and a fourth liquid outlet 641 is opened in the drain pipe 691.

[0034] The method for recovering rare earth elements from porcelain clay resources of this embodiment comprises the following steps: S1. In the process of beneficiation of porcelain clay ore (kaolin ore), porcelain mud slurry is carefully selected and added into the stirring barrel 8 for stirring until the porcelain mud is stirred into a slurry, and the stirring barrel 8 is kept stirring to prevent the porcelain mud from settling. The slurried porcelain mud is then injected into the first filter press 21 through the forward feed pipe 271 and the forward feed port 211 respectively in cooperation with the high-pressure mud pump, and the first filter press 21 is started once, and the piston rod of the first propulsion hydraulic cylinder 25 of the first filter press 21 is extended to push the multiple first filter press bags 24 to be compressed to squeeze the porcelain mud until the water content of the porcelain mud is 25-30%.

[0035] S2. At a pressure value of 8Mpa, the filtration state of the first filter press 21 is kept unchanged, the medicine tank 26 transports ammonium sulfate to the medicine feed pipeline 261, and the main gas source transports high-pressure gas to the blowing pipeline 281 and the back-blowing pipeline 282 respectively, so that the ammonium sulfate in the medicine feed pipeline 261 is pumped into the multiple first air film hoses 221 and the multiple second air film hoses 222 under high pressure, and then the high-pressure ammonium sulfate is injected into the porcelain mud in the extruded state through the multiple first air film hoses 221 and the multiple second air film hoses 222 respectively. Similarly, wash water and compressed air are pumped into the first filter press 21 in a high-pressure state in turn. In this way, under high pressure, the ionic rare earth elements in the ammonium sulfate leaching agent, wash water and porcelain mud materials are ion exchanged in the first filter press 21, and most of the ionic rare earth elements are exchanged and dissolved in the ammonium sulfate leaching agent and wash water, and blown out with compressed air until the rare earth leachate, wash water and porcelain mud products are blown out; Among them, when it is necessary to discharge the porcelain mud waste in the first filter press 21, in order to maintain the filtration state at this time, the first filter press 21 will only drive the first filter press bag 24 to filter once. Therefore, when it is necessary to output the porcelain mud product, it is necessary to simultaneously supplement high-pressure porcelain mud to ensure that the porcelain mud pressure in the first filter press bag 24 remains unchanged. For this, the forward feed pipe 271 first transports the porcelain mud to the reverse feed pipe 272, and then inputs high-pressure gas to the reverse feed pipe 272 through the backblowing pipe 282, so as to inject the porcelain mud into the first filter press bag 24 through the reverse feed port 212 in a high-pressure state, so as to squeeze the porcelain mud product through the forward feed port 211 to the forward feed pipe 271 while maintaining the pressure, and then transport it to the discharge pipe 273, and finally transport it to the stirring tank 91 through the discharge pipe 273.

[0036] S3. The rare earth leachate and washing water leached in step S2 are collected in the water tank 29 through the fifth liquid outlet 241, and then the rare earth leachate in the water tank 29 is transported to the clarification tank 1 for standing until the solid and liquid are separated, and then the liquid part in the clarification tank 1 is transported to the impurity removal tank 4, and the solid part is poured back into the stirring barrel 8 to be mixed with the porcelain mud slurry.

[0037] S4. 0.5 kg / t ammonium bicarbonate solution is added to the impurity removal tank 4 through the first feeder 31, stirred and allowed to stand until solid and liquid layers are separated, and then the impurity-removed rare earth leaching solution is transported to the sedimentation tank 6, and the solid part is discharged.

[0038] S5. A qualified ammonium bicarbonate solution precipitant is quantitatively added into the sedimentation tank 6 through the second feeder 32, and the rare earth elements are fully stirred to form rare earth carbonate precipitation; the rare earth precipitation mother liquor is then allowed to stand until solid-liquid separation occurs, and then the rare earth precipitation mother liquor is transported to the regeneration tank 7, and the precipitated rare earth carbonate slurry is transported to the second filter press (64) by a mud pump for solid-liquid separation; the rare earth precipitation mother liquor after filter pressing is transported to the regeneration tank 7, and the solid part is the rare earth carbonate product.

[0039] S6. Add ammonium sulfate solid into the regeneration pool 7 through the third feeder, stir and then let stand until the solid and liquid are separated, take the liquid part to form ammonium sulfate leaching agent, and the ammonium sulfate leaching agent can be transported to the stirring barrel 8 through the reflux pipe 71 for reuse.

[0040] In this embodiment, the porcelain mud product after the filter press in step S2 needs to be subjected to an iron removal process. Specifically, the porcelain mud product after the filter press in step S2 is poured into a stirring tank 91 for stirring, slurrying and washing, and then the stirred and washed porcelain mud product is poured into a third filter press 92 for filter press to obtain metal porcelain mud and washing water; the washing water is then transported to a sedimentation tank 6, and the metal porcelain mud is poured into a stirring tank for stirring, slurrying, and then magnetically separated and iron-removed by a magnetic separator 93 in turn. After magnetic de-ironization, the porcelain mud can be divided into two parts, one part of the screened porcelain mud is filtered through a fourth filter press 94, and the other part of the screened porcelain mud is filtered through the fourth filter press 94 to obtain high-white porcelain mud and iron-containing porcelain mud, respectively.

[0041] In this embodiment, all the obtained liquid can be reused without external discharge. Embodiment 2:

[0042] The difference between the second embodiment and the first embodiment is that the first filter press 2 in step S2 continuously presses the material in the first filter bag 24 at a pressure value of 6 MPa.

[0043] Comparative Example 1: The difference between this comparative example and the first embodiment is that step S2 is different, specifically: S2. The first filter press 21 is kept in the filter pressing state, and the first propulsion hydraulic cylinder 25 does not apply the squeezing force, that is, the material in the first filter bag 24 is no longer squeezed continuously, the medicine tank 26 delivers the ammonium sulfate to the medicine feed pipe 261, and the main gas source delivers the high-pressure gas to the blowing pipe 281 and the back-blowing pipe 282 respectively, so as to pump the ammonium sulfate in the medicine feed pipe 261 into the multiple first air film hoses 221 and the multiple second air film hoses 222 under the state of high pressure, and then the ammonium sulfate in the medicine feed pipe 261 is pumped into the multiple first air film hoses 221 and the multiple second air film hoses 222 through the multiple first air film hoses 221 and the multiple second air film hoses 222. The second air film hose 222 respectively injects high-pressure ammonium sulfate into the porcelain mud in the extruded state. Similarly, wash water and compressed air are pumped into the first filter press 21 in a high-pressure state in turn. In this way, when the slurry is no longer continuously extruded, the ionic rare earth elements in the ammonium sulfate leaching agent, wash water and porcelain mud material are ion exchanged in the first filter press 21. Most of the ionic rare earth elements are exchanged and dissolved in the ammonium sulfate leaching agent and wash water, and are blown out with compressed air until the rare earth leaching liquid, wash water and porcelain mud products are blown out; Among them, when it is necessary to discharge the porcelain mud waste in the first filter press 21, in order to maintain the filtration state at this time, the first filter press 21 will only drive the first filter press bag 24 to filter once. Therefore, when it is necessary to output the porcelain mud product, it is necessary to simultaneously supplement high-pressure porcelain mud to ensure that the porcelain mud pressure in the first filter press bag 24 remains unchanged. For this, the forward feed pipe 271 first transports the porcelain mud to the reverse feed pipe 272, and then inputs high-pressure gas to the reverse feed pipe 272 through the backblowing pipe 282, so as to inject the porcelain mud into the first filter press bag 24 through the reverse feed port 212 in a high-pressure state, so as to squeeze the porcelain mud product through the forward feed port 211 to the forward feed pipe 271 while maintaining the pressure, and then transport it to the discharge pipe 273, and finally transport it to the stirring tank 91 through the discharge pipe 273.

[0044] The subsequent steps S1, S3 to S6 are the same as those in the first embodiment and will not be described again here.

[0045] Comparative Example 2: The difference between this comparative example and the first embodiment is that step S2 is different, specifically: S2. At a pressure value of 3Mpa, the filtration state of the first filter press 21 is kept unchanged, the medicine tank 26 transports ammonium sulfate to the medicine feed pipeline 261, and the main gas source transports high-pressure gas to the blowing pipeline 281 and the back-blowing pipeline 282 respectively, so that the ammonium sulfate in the medicine feed pipeline 261 is pumped into the multiple first air film hoses 221 and the multiple second air film hoses 222 under high pressure, and then the high-pressure ammonium sulfate is injected into the porcelain mud in the extruded state through the multiple first air film hoses 221 and the multiple second air film hoses 222 respectively. Similarly, the washing water and compressed air are pumped into the first filter press 21 in a high-pressure state in turn. In this way, under the high-pressure state, the ionic rare earth elements in the ammonium sulfate leaching agent, the washing water and the porcelain mud material are ion exchanged in the first filter press 21, and most of the ionic rare earth elements are exchanged and dissolved in the ammonium sulfate leaching agent and the washing water, and are blown out with compressed air until the rare earth leachate, the washing water and the porcelain mud products are blown out; Among them, when it is necessary to discharge the porcelain mud waste in the first filter press 21, in order to maintain the filtration state at this time, the first filter press 21 will only drive the first filter press bag 24 to filter once. Therefore, when it is necessary to output the porcelain mud product, it is necessary to simultaneously supplement high-pressure porcelain mud to ensure that the porcelain mud pressure in the first filter press bag 24 remains unchanged. For this, the forward feed pipe 271 first transports the porcelain mud to the reverse feed pipe 272, and then inputs high-pressure gas to the reverse feed pipe 272 through the backblowing pipe 282, so as to inject the porcelain mud into the first filter press bag 24 through the reverse feed port 212 in a high-pressure state, so as to squeeze the porcelain mud product through the forward feed port 211 to the forward feed pipe 271 while maintaining the pressure, and then transport it to the discharge pipe 273, and finally transport it to the stirring tank 91 through the discharge pipe 273.

[0046] The subsequent steps S1, S3 to S6 are the same as those in the first embodiment and will not be described again here.

[0047] Comparative Example 3: The difference between this comparative example and the first embodiment is that step S1 and step S2 are different, specifically: S2. Open multiple first filter bags 24, and the first propulsion hydraulic cylinder 25 does not apply extrusion force, that is, the material in the first filter bags 24 is no longer continuously squeezed. The medicine tank 26 transports ammonium sulfate to the medicine feed pipe 261, and then adds ammonium sulfate to the porcelain mud in an extruded state through multiple first air film hoses 221 and multiple second air film hoses 222 to perform ion exchange. Most of the ionic rare earth elements are exchanged and dissolved in the ammonium sulfate leaching agent. Then, the first propulsion hydraulic cylinder 25 is controlled to push the multiple first filter bags 24 to be compressed. After repeating the above steps N times, rare earth leaching solution and porcelain mud products are obtained.

[0048] The subsequent steps S1, S3 to S6 are the same as those in the first embodiment and will not be described again here.

[0049] The raw materials of the same batch and weight are used to recover rare earth elements according to the methods of Example 1, Comparative Example 1, Comparative Example 2 and Comparative Example 3. The mass percentage of the corresponding recovered rare earth carbonate products and raw materials is shown in the following table: The above-mentioned continuous extrusion means that after the filter press extrudes the slurry once, it continues to extrude at a rated pressure value, and at the same time, the slurry is continuously injected into the filter bag of the filter press at a rated flow rate.

[0050] The embodiments described above are only preferred embodiments of the present invention and are not intended to limit the present invention in any form. Any technician familiar with the art can use the above disclosed technical content to make more possible changes and modifications to the technical solution of the present invention without departing from the scope of the technical solution of the present invention, or modify it into an equivalent embodiment of equivalent changes. Therefore, all equivalent and equivalent changes made according to the ideas of the present invention without departing from the content of the technical solution of the present invention should be included in the protection scope of the present invention.

Claims

1. A system for recovering rare earth elements from porcelain clay resources, comprising a clarifier (1), a first filter press (21), a second filter press (64), a third filter press (92), a fourth filter press (94), a first feeder (31), a second feeder (32), a decontamination tank (4), a sedimentation tank (6), and a regeneration tank (7), characterized in that: The clarification tank (1) is provided with a first liquid outlet (11) and a first discharge outlet (12), the first liquid outlet (11) being connected to the impurity removal tank (4), and the first discharge outlet (12) being connected to a first filter press (21); The impurity removal tank (4) is provided with a second liquid outlet (41) and a second discharge outlet (42); the second liquid outlet (41) is connected to a sedimentation tank (6); the sedimentation tank (6) is provided with a third liquid outlet (61) and a third discharge outlet (62); the third discharge outlet (62) is connected to a second filter press (64); the second filter press (64) is provided with a fourth liquid outlet (641) and a fourth discharge outlet; the third liquid outlet (61) and the fourth liquid outlet (641) are respectively connected to a regeneration tank (7); wherein the first feeder (31) is used to feed ammonium carbonate into the impurity removal tank (4); and the second feeder (32) is used to feed ammonium carbonate into the sedimentation tank (6).

2. A system for recovering rare earth elements from porcelain clay resources according to claim 1, characterized in that: A reflux pipe (71) is connected between the regeneration tank (7) and the stirring barrel (8).

3. A system for recovering rare earth elements from porcelain clay resources according to claim 2, characterized in that: The first filter press (21) comprises a first frame (22), two first sliding guide rails (23), a plurality of first filter press bags (24), a first propulsion hydraulic cylinder (25), a plurality of first air film hoses (221), and a plurality of second air film hoses (222). The two first sliding guide rails (23) are respectively arranged horizontally on the first frame (22). The plurality of first filter press bags (24) slide on the first sliding guide rails (23) respectively. The plurality of first filter press bags (24) are arranged at equal intervals along the length direction of the sliding guide rails. The first propulsion hydraulic cylinder (25) is connected to the first filter press bag (24) at the front end, and the first filter press bag (24) at the rear end is connected to the first frame (22). Each of the first filter press bags (24) is respectively connected to a first air film hose (221) and a second air film hose (222).

4. A system for recovering rare earth elements from porcelain clay resources according to claim 3, characterized in that: The first filter press bag (24) located at the rear end is connected to a forward feed inlet (211), and the first filter press bag (24) located at the front end is connected to a reverse feed inlet (212).

5. A system for recovering rare earth elements from porcelain clay resources according to claim 4, characterized in that: It also includes a medicine tank (26), a medicine feed pipeline (261), a forward feed pipeline (271), a reverse feed pipeline (272), an air blowing pipeline (281), and a back-blowing pipeline (282). The medicine tank (26) is connected to the medicine feed pipeline (261), the medicine feed pipeline (261) is respectively connected to a plurality of first air film hoses (221) and a plurality of second air film hoses (222), the forward feed pipeline (271) is respectively connected to a forward feed port (211) and a reverse feed pipeline (272), the reverse feed pipeline (272) is connected to a reverse feed port (212), a main air source is connected to the back-blowing pipeline (282), the back-blowing pipeline (282) is respectively connected to the reverse feed pipeline (272) and the air blowing pipeline (281), and the air blowing pipeline (281) is connected to the medicine feed pipeline (261).

6. A system for recovering rare earth elements from porcelain clay resources according to claim 5, characterized in that: The second filter press (64), the third filter press (92), and the fourth filter press (94) all include a second frame (65), two second sliding guide rails (66), a plurality of second filter press bags (67), and a second propulsion hydraulic cylinder (68). The two second sliding guide rails (66) are respectively arranged horizontally on the second frame (65). The plurality of second filter press bags (67) slide on the second sliding guide rails (66). The plurality of second filter press bags (67) are arranged at equal intervals along the length direction of the second sliding guide rails (66). The second propulsion hydraulic cylinder (68) is connected to the second filter press bag (67) at the front end, and the second filter press bag (67) at the rear end is connected to the second frame (65).

7. A method for recovering rare earth elements from porcelain clay resources as claimed in claim 6, characterized in that: The following steps are involved: S1. The porcelain mud is added to a mixing barrel (8) and stirred until the porcelain mud is stirred and slurried, and then the slurried porcelain mud is poured into a first filter press (21) for filtration until the porcelain mud is filtered to a water content of 25 to 30%; S2. Keep the first filter press (21) at the set pressure value while keeping the filter press in a fixed state, and sequentially pump ammonium sulfate, wash water, and compressed air into the porcelain mud of the first filter press (21) until the rare earth leachate, wash water, and porcelain mud product are blown out; S3. The collected rare earth leachate and washing water are transported to a clarification tank (1) and allowed to stand until solid-liquid separation occurs; the qualified rare earth leachate in the clarification tank (1) is then transported to a decontamination tank (4), and the solid portion is mixed with the porcelain mud slurry in the stirring barrel (8) in step S1; S4. quantitatively adding a qualified ammonium bicarbonate solution to the impurity removal tank (4) through the first feeder (31), stirring and controlling the pH value of the solution to remove impurities; then standing until the solid-liquid separation, and transporting the impurity-removed rare earth leachate to the sedimentation tank (6), and discharging the solid part; S5. quantitatively adding a qualified ammonium bicarbonate solution precipitant into the sedimentation tank (6) through the second feeder (32), stirring the rare earth elements to form rare earth carbonate precipitates, and then standing until solid-liquid separation, and then transporting the rare earth precipitation mother liquor to the regeneration tank (7), and sending the precipitated rare earth carbonate slurry part into the second filter press (64) by a mud pump for solid-liquid separation; the rare earth precipitation mother liquor after filter pressing is transported to the regeneration tank (7), and the solid part is the rare earth carbonate product; S6. The ammonium sulfate solid is quantitatively added to the regeneration tank (7) through the third feeder, stirred and dissolved, and then allowed to stand for stratification, and the liquid part is regenerated into ammonium sulfate leaching agent.

8. The method for recovering rare earth elements from porcelain clay resources according to claim 7, characterized in that: The pressure value in step S2 is set to 6-8 MPa.

9. A method for recovering rare earth elements from porcelain clay resources according to claim 8, characterized in that: The porcelain mud product after the filter pressing in step S2 is poured into a stirring tank (91) for stirring, slurrying and washing. The stirred and washed porcelain mud product is poured into a third filter press (92) for filter pressing to obtain rare earth element-removed porcelain mud and washing water.

10. The method for recovering rare earth elements from porcelain clay resources according to claim 9, characterized in that: The washing water is transported to the sedimentation tank (6), and the porcelain mud from which the rare earth elements have been removed is poured into a stirring tank for stirring and slurrying, and then is magnetically separated and iron-removed by a magnetic separator (93); and then the mud is respectively pumped into a fourth filter press (94) for filtration to obtain high-white porcelain mud and iron-containing porcelain mud.

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