Process for extracting and separating rare earths

Abstract

The present application relates to the technical field of extracting rare earth, and particularly relates to an extraction rare earth separation process method. Fluorine-carbon cerium ore crude ore is treated to obtain activated ore powder. The activated ore powder is subjected to alkali pressure boiling oxidation, roasting transformation and optimal dissolution leaching to obtain a purified liquid. The purified liquid is then subjected to barium chloride sulfuric acid removal, lead removal by sulfurized lead, pH adjustment and the like to obtain a low-impurity chlorinated rare earth liquid. The chlorinated rare earth liquid is subjected to multi-stage extraction to obtain a neodymium chloride solution, a praseodymium-neodymium chloride solution and a lanthanum-cerium chloride solution. The solutions are subjected to oxalic acid precipitation and calcination to obtain a rare earth oxide product. The present application adopts fine pretreatment, multi-stage differential extraction and purification processes to achieve efficient separation of lanthanum-cerium, praseodymium-neodymium and neodymium in fluorine-carbon cerium ore and improve product purity.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of extracting rare earth, and particularly relates to a separation process method for extracting rare earth. BACKGROUND

[0002] Rare earth elements have irreplaceable roles in new energy, aerospace, electronic information and other fields due to their unique physical and chemical properties. Fluorcarbon cerium ore is one of the most abundant rare earth mineral resources in China, and its rare earth distribution is mainly light rare earth (cerium distribution is about 50%, praseodymium and neodymium distribution is 14% to 26%), and is associated with fluorine, calcium, iron and other impurities.

[0003] The atomic structures of rare earth elements are similar, and their chemical properties are similar. In particular, the separation of lanthanum, cerium, praseodymium and neodymium in light rare earth is extremely difficult. Traditional extraction processes mostly use a single extraction system and extensive parameter control, and it is difficult to achieve efficient separation of rare earth elements. The purity of the product is generally lower than 99.0%, and it cannot meet the demand of high-end materials for high-purity rare earth.

[0004] At the same time, the traditional extraction process also has many defects: first, fluorine pollution. Fluorine in fluorcarbon cerium ore is easy to release in the form of hydrogen fluoride or fluoride ion. The traditional process lacks specific defluorination design, resulting in excessive fluorine content in waste water; second, low recovery rate of high-value rare earth. Medium and heavy rare earth is easy to be lost with waste slag, and the recovery rate of key light rare earth such as praseodymium and neodymium is less than 95%; third, high energy consumption and high reagent consumption. The design of high temperature and high pressure reaction link is unreasonable, the loss of extractant is large and the regeneration efficiency is low; fourth, incomplete impurity control. Iron, lead, sulfate and other impurities are easy to be brought into the subsequent process, affecting the product quality. SUMMARY

[0005] In order to solve the problems existing in the prior art, the present application provides a separation process method for extracting rare earth, which realizes efficient separation of lanthanum, cerium, praseodymium and neodymium in fluorcarbon cerium ore and improves the purity of the product through fine pretreatment, multi-stage differential extraction and purification process.

[0006] To achieve the above purpose, a separation process method for extracting rare earth includes the following steps:

[0007] S1, fluorcarbon cerium ore is treated to obtain activated ore powder. The activated ore powder is subjected to alkali pressure boiling oxidation, roasting transformation and optimal dissolution leaching to obtain a purified liquid. The purified liquid is then subjected to barium chloride to remove sulfate and lead sulfide to remove lead. The pH is adjusted to 3.5 to obtain a low-impurity chlorinated rare earth liquid;

[0008] S2, the extractant P507 is prepared into a blank organic phase in an equal proportion with kerosene. The blank organic phase is subjected to saponification treatment with a mass fraction of 30% liquid alkali, and the saponification degree is controlled at 0.8 to 1.2 mol / L to obtain a saponified organic phase;

[0009] S3, the chlorinated rare earth liquid and the saponified organic phase are injected into the extraction tank at a phase ratio of 1:3, the temperature is controlled at 25℃, multi-stage countercurrent extraction is performed, and phase separation is performed after standing to obtain a lanthanum-cerium-praseodymium-neodymium mixed liquid and a loaded organic phase loaded with medium and heavy rare earths, the loaded organic phase is subjected to multi-stage back extraction with a 20wt% hydrochloric acid solution to obtain a medium and heavy rare earth liquid and a regenerated organic phase;

[0010] S4, the lanthanum-cerium-praseodymium-neodymium mixed liquid and the saponified organic phase are injected into the extraction tank at a phase ratio of 1:8, the temperature is controlled at 60℃, multi-stage countercurrent extraction is performed, and phase separation is performed after standing to obtain an organic phase loaded with praseodymium-neodymium and a lanthanum-cerium chloride solution;

[0011] S5, the temperature is controlled at 60℃, the organic phase loaded with praseodymium-neodymium is subjected to multi-stage countercurrent washing with a 20wt% hydrochloric acid solution to obtain a first purified loaded organic phase and a washing waste liquid;

[0012] S6, the first loaded organic phase and the 20wt% hydrochloric acid solution are injected into a pure neodymium tank at a phase ratio of 8:1, the temperature is controlled at 60℃, multi-stage countercurrent extraction is performed, and phase separation is performed after standing to obtain an organic phase loaded with neodymium and a praseodymium-neodymium chloride solution;

[0013] S7, the temperature is controlled at 60℃, the organic phase loaded with neodymium is subjected to multi-stage countercurrent washing with a 20wt% hydrochloric acid solution to obtain a second purified loaded organic phase and a washing waste liquid;

[0014] S8, the second loaded organic phase enters a multi-stage back extraction section, neodymium is transferred from the organic phase to the aqueous phase to obtain a neodymium chloride solution and a regenerated organic phase;

[0015] S9, a 10wt% oxalic acid solution is slowly added to the neodymium chloride solution, the praseodymium-neodymium chloride solution, and the lanthanum-cerium chloride solution at a rare earth ion to oxalic acid molar ratio of 1:1.2, respectively, stirring is started, the temperature is raised to 70℃, constant temperature stirring is performed for 2h, stirring is stopped after standing for 4h, and a rare earth oxalate precipitate is obtained, the rare earth oxalate precipitate is vacuum filtered, the filter cake is washed with deionized water until the filtrate is neutral, and the washed filter cake is sent to a calcination furnace, calcination is performed at 850℃ for 4h, after calcination, the furnace is cooled to room temperature, and the rare earth oxide product is obtained.

[0016] Preferably, the preparation process of the activated ore powder comprises:

[0017] 1) The fluorcarbonate ore is coarsely crushed and then medium crushed to obtain a medium crushed product with a particle size of ≤5mm;

[0018] 2) The medium crushed product is mixed with water at a liquid-solid ratio of 5:1, 0.1wt% sodium hexametaphosphate is added based on the mass of the ore, the slurry is pumped into a ball mill for grinding, a hydrocyclone is used for classification to obtain sand and overflow slurry with a particle size of ≤200 mesh accounting for ≥85%, and the sand is returned to the ball mill for grinding;

[0019] 3) Pump the overflow slurry to the flotation tank, add 20% sodium carbonate solution to adjust the pH of the overflow slurry to 9.0, start stirring, add quartz depressant, calcium and magnesium gangue depressant, fluorite collector, foaming agent, aerofloat, open the scraper device, continuously scrape and collect the floating foam, and obtain the rough concentrate;

[0020] 4) Dilute the rough concentrate with water to a liquid-solid ratio of 5:1, pump it into the cleaning tank, add quartz depressant, aerofloat, collect the floating foam of the cleaning tank, and obtain the concentrate slurry;

[0021] 5) Dilute or vacuum concentrate the concentrate slurry, adjust the concentrate slurry concentration to 50%, add the concentrate slurry with adjusted concentration to the planetary ball mill for grinding, set the ball-to-material ratio to 10:1, filter, dry, and obtain the activated ore powder.

[0022] Preferably, the quartz depressant is water glass, and the addition amount is 200 g / t of raw ore.

[0023] Preferably, the calcium and magnesium gangue depressant is compounded by sodium hexametaphosphate and sodium citrate at a mass ratio of 1:1, and the addition amount is 150 g / t of raw ore.

[0024] Preferably, the fluorite collector is compounded by hydroxamic acid and oleic acid at a mass ratio of 3:1, and the addition amount is 80 g / t of raw ore.

[0025] Preferably, the foaming agent is pine oil, and the addition amount is 20 g / t of raw ore.

[0026] Preferably, the preparation process of alkali pressure oxidation includes:

[0027] 1) Add the activated ore powder and 50% NaOH solution at a weight ratio of 1:0.8-1.2 to the reaction kettle, add 3wt% sodium carbonate based on the amount of NaOH solution, start stirring at a speed of 300 r / min, and pre-treat at 85°C for 30 min;

[0028] 2) After the pre-treatment is completed, oxygen-enriched air is introduced to a pressure of 1.2 MPa, the temperature is raised to 160°C, and the temperature is maintained for 4 h. After the temperature is lowered to 80°C, the pressure is released to normal pressure, the slurry is discharged through the bottom valve to the plate and frame filter press for filtration, and a filter cake rich in rare earth hydroxide is obtained.

[0029] Preferably, the preparation process of roasting transformation includes:

[0030] The filter cake obtained by alkali pressure oxidation is washed with 80°C water until the pH of the filtrate is ≤8.5, sent to the kiln by a screw conveyor, roasted at 700°C for 2 h under the condition of air introduction, and cooled to room temperature to obtain a roasted ore powder rich in rare earth oxides.

[0031] Preferably, the preparation process of optimal leaching includes:

[0032] The roasted ore powder is mixed with water to a concentration of 35% to 45%, 10% of hydrochloric acid solution and ammonium sulfate are added, the amount of hydrochloric acid solution is 1.2 times of the mass of the roasted ore powder, the amount of ammonium sulfate is 1 wt% of the mass of the roasted ore powder, the temperature is raised to 60 DEG C, and the reaction is kept for 2 hours, then filtration is performed to obtain a leaching solution and a leaching residue.

[0033] Preferably, the preparation process of the purified solution comprises:

[0034] 1) 6 mol / L hydrochloric acid solution is added to the leaching residue, the liquid-solid ratio is 3:1, 5% hydrogen peroxide solution is added, the amount is 1.5 L / kg of the leaching residue, the temperature is raised to 85 DEG C, and the reaction is kept for 3 hours, then filtration is performed, and the filtrate is combined with the leaching solution to obtain a leaching solution;

[0035] 2) 20% hydrogen peroxide solution is added to the leaching solution, the amount is 1.5 wt% of the leaching solution, and the oxidation is kept for 20 minutes, 20% NaOH solution is added, the pH of the system is adjusted to 2, 0.1 wt% polyacrylamide of the total mass of the leaching solution is added, the stirring is kept for 30 minutes at a speed of 150 r / min, and the system is kept for 1 hour for sedimentation, then the precipitate is filtered out, and the pH is adjusted to 3.5 by using 10% ammonia water, the stirring is kept for 40 minutes, and then filtration is performed to obtain a purified solution.

[0036] After the above technical scheme is adopted, the application has the following beneficial effects:

[0037] The application realizes the efficient separation of lanthanum, cerium, praseodymium and neodymium in fluorocarbon cerium ore by using fine pretreatment, multi-stage differential extraction and purification process, and improves the product purity. DETAILED DESCRIPTION

[0038] In order to make the purpose, technical scheme and advantages of the application more clear and explicit, the application is further described in detail below by combining with specific examples. It should be understood that the specific examples described herein are only configured to explain the application, and are not configured to limit the application. The application can be implemented without some of the specific details by those skilled in the art. The following description of the examples is only to provide a better understanding of the application by showing examples of the application.

[0039] Example 1

[0040] The embodiment provides a rare earth separation process method, and first, fluorcarbonate cerium ore is treated to obtain activated ore powder. The activated ore powder is subjected to alkali pressure boiling oxidation, roasting transformation and optimal dissolution leaching to obtain a purified liquid. Then, the purified liquid is subjected to barium chloride desulfation and lead removal by zinc sulfide. The pH is adjusted to 3.5 to obtain a chlorinated rare earth liquid with low impurities. The chlorinated rare earth liquid is subjected to multi-stage extraction to obtain a neodymium chloride solution, a praseodymium-neodymium chloride solution and a lanthanum-cerium chloride solution. The rare earth oxide product is obtained through oxalic acid precipitation and calcination. The following are specific process steps and technical details.

[0041] Step one, crushing of the raw ore

[0042] The fluorcarbonate cerium ore is fed into a jaw crusher through a vibrating feeder, and is crushed to a particle size of ≤50 mm to obtain a coarse crushing product. The coarse crushing product is fed into an impact crusher through a belt conveyor, and is classified through a circular vibrating screen. The coarse particles on the screen are returned to the impact crusher, and the fine particles under the screen are collected to obtain a medium crushing product with a particle size of ≤5 mm.

[0043] Step two, pre-flotation grinding

[0044] The medium crushing product is uniformly mixed with water at a liquid-solid ratio of 5:1 to form a slurry, which is then pumped into a ball mill for grinding. The steel ball ratio is Φ80:Φ60:Φ40=2:5:3, and the grinding time is 40 min. The ground ore product is classified by a hydrocyclone to obtain sand and overflow slurry with a particle size of ≤200 mesh, accounting for ≥85%. The sand is returned to the ball mill for recycling.

[0045] Step three, flotation enrichment and activation

[0046] The overflow slurry is pumped into a flotation tank, and a 20% sodium carbonate solution is added while stirring to adjust the pH of the overflow slurry to 9.0, thereby enhancing the adsorption capacity of the collector on rare earth minerals in the subsequent process.

[0047] After the pH stabilizes, quartz inhibitors (water glass) are added at a dosage of 200 g / ton of raw ore, and stirred for 5 min to inhibit quartz gangue. Then, calcium and magnesium gangue inhibitors (sodium citrate and sodium citrate are compounded at a mass ratio of 1:1) are added at a dosage of 150 g / ton of raw ore, and stirred for 5 min to complex Ca 2+ , Mg 2+ in calcite and fluorite. Then, fluorcarbonate cerium ore collectors (isoxazoles and oleic acid are compounded at a mass ratio of 3:1) are added at a dosage of 80 g / ton of raw ore, and stirred for 5 min to allow the carboxyl anion of oleic acid to chemically adsorb rare earth ions. Finally, pine oil is added as a foaming agent at a dosage of 20 g / ton of raw ore, and stirred for 2 min to reduce the gas-liquid interfacial tension and stabilize the bubble layer.

[0048] After all the reagents are added, the air supply of the flotation machine is set to 0.3 m 3 / (m 2• min), turn on the scraping device, continuously scrape and collect the floating froth, and obtain the rough concentrate. Dilute the rough concentrate with water to a liquid-solid ratio of 5:1, pump it into the cleaning tank, add water glass again, the amount is 50 g / t of raw ore, and the air amount is 0.2 m 3 / (m 2 • min), collect the floating froth of the cleaning tank, and obtain the concentrate slurry.

[0049] Dilute the concentrate slurry with water or vacuum concentrate, adjust the concentrate slurry concentration to 50%, and add the concentrate slurry with adjusted concentration into a planetary ball mill for grinding, set the ball-ore ratio to 10:1, the agate ball ratio to Φ20:Φ10=1:1, the rotation speed to 300 r / min, continuously activate for 60 min, filter and dry, and obtain the activated ore powder. The mineral structure is changed by high-frequency mechanical force, the fluorocarnellite lattice is destroyed, and the reaction activity in the subsequent process is strengthened.

[0050] Step four, alkali pressure cooking oxidation leaching

[0051] Add the activated ore powder and a NaOH solution with a mass fraction of 50% into a reaction kettle according to a weight ratio of 1:0.8, add 3wt% of sodium carbonate based on the amount of the NaOH solution, start stirring at a rotation speed of 300 r / min, pre-treat at 85℃ for 30 min, then pass in oxygen-rich air to a pressure of 1.2 MPa, heat to 160℃, and keep the temperature for 4 h, then cool to 80℃, release the pressure to normal pressure, discharge the slurry through the bottom valve to a plate-and-frame filter press for filtration, and obtain a filter cake rich in rare earth hydroxides.

[0052] Wash the filter cake with 80℃ water until the pH of the filtrate is less than or equal to 8.5, send it into a kiln through a screw conveyor, and roast it at 700℃ for 2 h under the condition of passing in air, and cool it to room temperature to obtain a roasted ore powder rich in rare earth oxides. Add water to the roasted ore powder to adjust the slurry concentration to 35%, add ammonium sulfate and a hydrochloric acid solution with a mass fraction of 10%, the amount of the hydrochloric acid solution is 1.2 times the mass of the roasted ore powder, and the amount of ammonium sulfate is 1wt% of the mass of the roasted ore powder, to strengthen fluorine fixation. Heat to 60℃, keep the temperature for 2 h, filter, and obtain a pregnant solution and a pregnant residue.

[0053] Step five, purification and impurity removal

[0054] Add a hydrochloric acid solution with a concentration of 6 mol / L to the pregnant residue, the liquid-solid ratio is 3:1, add a hydrogen peroxide solution with a mass fraction of 5%, the amount is 1.5 L / kg of the pregnant residue, heat to 85℃, stir for 3 h, filter, and combine the filtrate with the pregnant solution to obtain a leaching solution.

[0055] The leaching solution is added with 20% mass fraction hydrogen peroxide, the amount is 1.5wt% of the leaching solution, and is oxidized for 20 minutes. Then, 20% mass fraction NaOH solution is added, the system pH is adjusted to 2, 0.1wt% of the total mass of the leaching solution is added with polyacrylamide, stirred for 30 minutes at 150r / min, and is settled for 1 hour. After the precipitate is filtered out, the pH is adjusted to 3.5 with 10% mass fraction ammonia water, stirred for 40 minutes, and is filtered to obtain the purified solution.

[0056] The purified solution is added with 10% mass fraction barium chloride aqueous solution to remove sulfate, and is added with 5% mass fraction sodium sulfide solution to remove lead. Finally, 10% mass fraction ammonia water is added dropwise to adjust the system pH to 3.5 to obtain the low-impurity chlorinated rare earth solution.

[0057] Step six, preparation of organic phase

[0058] The blank organic phase is prepared by mixing the extractant P507 with kerosene in equal proportion, and is saponified by 30% mass fraction liquid alkali, and the saponification degree is controlled to 0.8mol / L to obtain the saponified organic phase.

[0059] Step seven, separation of medium and heavy rare earths

[0060] The chlorinated rare earth solution and the saponified organic phase are injected into the extraction tank according to the phase ratio of 1:3, the temperature is controlled to 25℃, and is extracted by 20-stage countercurrent extraction, and is settled and separated to obtain the lanthanum-cerium-praseodymium-neodymium mixed solution and the loaded organic phase loaded with medium and heavy rare earths (such as samarium, europium, gadolinium). The loaded organic phase is multi-stage back-extracted with 20% mass fraction hydrochloric acid solution to obtain the medium and heavy rare earth solution and the regenerated organic phase.

[0061] Step eight, separation of lanthanum and cerium

[0062] The lanthanum-cerium-praseodymium-neodymium mixed solution and the saponified organic phase are injected into the extraction tank according to the phase ratio of 1:8, the temperature is controlled to 60℃, and is extracted by 20-stage countercurrent extraction, and is settled and separated to obtain the organic phase loaded with praseodymium-neodymium and the chlorinated lanthanum-cerium solution, and the preliminary separation of lanthanum and cerium from praseodymium and neodymium is realized.

[0063] Step nine, separation of praseodymium and neodymium

[0064] The temperature is controlled to 60℃, the organic phase loaded with praseodymium and neodymium is multi-stage countercurrent washed with 20% mass fraction hydrochloric acid solution to obtain the first loaded organic phase after purification and the washing waste liquid. The first loaded organic phase and 20% mass fraction hydrochloric acid solution are injected into the pure neodymium tank according to the phase ratio of 8:1, the temperature is controlled to 60℃, and is extracted by multi-stage countercurrent extraction, and is settled and separated to obtain the organic phase loaded with neodymium and the chlorinated praseodymium-neodymium solution.

[0065] Step ten, separation of neodymium

[0066] The temperature is controlled at 60℃, the neodymium-loaded organic phase is washed by multi-stage countercurrent with 20% hydrochloric acid solution to obtain the purified second loaded organic phase and the washing waste liquid. The second loaded organic phase enters the multi-stage stripping section, and neodymium is transferred from the organic phase to the aqueous phase to obtain a neodymium chloride solution and a regenerated organic phase.

[0067] Step eleven, precipitation and calcination

[0068] According to the molar ratio of rare earth ions to oxalic acid of 1:1.2, 10% oxalic acid solution is slowly added to the neodymium chloride solution, praseodymium neodymium chloride solution and lanthanum cerium chloride solution respectively, stirring is started, the temperature is raised to 70℃, constant temperature stirring is carried out for 2h, after the stirring is turned off, it is placed for 4h, and the rare earth oxalate precipitate is obtained. The rare earth oxalate precipitate is vacuum filtered, and the filter cake is washed with deionized water until the filtrate is neutral.

[0069] The washed filter cake is sent to a calcination furnace and calcined at 850℃ for 4h. After calcination, the furnace is cooled to room temperature, and the rare earth oxide product (lanthanum cerium oxide, neodymium oxide, praseodymium neodymium oxide) is obtained.

[0070] Example 2

[0071] The difference from Example 1 is:

[0072] In step four, the activated ore powder and 50% NaOH solution are added to the reaction kettle at a weight ratio of 1:1, 3wt% sodium carbonate is added based on the amount of NaOH solution, stirring is started at a speed of 300r / min, the temperature is raised to 85℃ for pretreatment for 30min, then oxygen-enriched air is introduced to a pressure of 1.2MPa, the temperature is raised to 160℃, and the temperature is maintained for 4h. After cooling to 80℃, the pressure is released to normal pressure, and the slurry is discharged through the bottom valve to the plate and frame filter press for filtration to obtain a filter cake rich in rare earth hydroxide.

[0073] In step four, the calcined ore powder is slurried with water to a concentration of 40%, ammonium sulfate and 10% hydrochloric acid solution are added, the amount of hydrochloric acid solution is 1.2 times the mass of the calcined ore powder, and the amount of ammonium sulfate is 1wt% of the mass of the calcined ore powder, which is used to strengthen fluorine fixation. The temperature is raised to 60℃, and the temperature is maintained for 2h. After filtration, an optimal solution and an optimal residue are obtained.

[0074] In step six, the extractant P507 is prepared into a blank organic phase by mixing with kerosene in equal proportions, and the blank organic phase is subjected to saponification treatment with 30% liquid caustic, the saponification degree is controlled at 1.0mol / L, and a saponified organic phase is obtained.

[0075] The steps and other conditions of the preparation method are the same as those of Example 1.

[0076] Example 3

[0077] The difference from Example 1 is:

[0078] In step four, the activated ore powder is added into a reaction kettle with a 50% NaOH solution in a weight ratio of 1:1.2, 3wt% sodium carbonate is added based on the amount of the NaOH solution, stirring is started at a speed of 300r / min, the temperature is raised to 85°C for pretreatment for 30min, then oxygen-enriched air is introduced to a pressure of 1.2MPa, the temperature is raised to 160°C, and the reaction is kept for 4h, the temperature is lowered to 80°C, and then the pressure is released to normal pressure, the slurry is discharged through the bottom valve to a plate-and-frame filter press for filtration, and a filter cake rich in rare earth hydroxide is obtained;

[0079] In step four, the roasted ore powder is slurried with water to a concentration of 45%, ammonium sulfate and a 10% hydrochloric acid solution are added, the amount of the hydrochloric acid solution is 1.2 times the mass of the roasted ore powder, and the amount of the ammonium sulfate is 1wt% of the mass of the roasted ore powder, which is used to strengthen fluorine fixation. The temperature is raised to 60°C, and the reaction is kept for 2h, and then filtration is performed to obtain a pregnant solution and a pregnant residue;

[0080] In step six, the extractant P507 is prepared into a blank organic phase in an equal proportion with kerosene, and the blank organic phase is subjected to saponification treatment with a 30% liquid alkali, and the saponification degree is controlled to be 1.2mol / L, and a saponified organic phase is obtained.

[0081] The preparation method of the embodiment 1 is used to prepare the product of the embodiment 2.

[0082] In order to better illustrate the embodiments of the present application, the final products of the embodiments 1-3 are subjected to purity detection, and the results are shown in Table 1.

[0083] Table 1: Comparison table of test indexes

[0084]

[0085] In accordance with the embodiments of the present application as described above, these embodiments do not describe all the details, and do not limit the present application to only the specific embodiments. Obviously, according to the above description, many modifications and changes can be made. The embodiments are selected and specifically described in this specification in order to better explain the principles and practical applications of the present application, so that those skilled in the art can well utilize the present application and make modifications and uses on the basis of the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A rare earth extraction and separation process, characterized in that, Includes the following steps: S1. Fluorocarbon cerium ore is processed to obtain activated mineral powder. The activated mineral powder is then subjected to alkaline pressure boiling oxidation, roasting transformation, and optimal leaching to obtain a purified solution. After that, it is subjected to barium chloride to remove sulfate and sodium sulfide to remove lead. The pH is adjusted to 3.5 to obtain a low-impurity rare earth chloride solution. The process for preparing the activated mineral powder includes: 1) Fluorocarbonate cerium ore is coarsely crushed and then mediumly crushed to obtain medium-crushed products with a particle size ≤5mm; 2) Mix the medium crushing product with water at a liquid-solid ratio of 5:

1. Based on the quality of the original ore, add 0.1wt% sodium hexametaphosphate to form a slurry. Then pump the slurry into a ball mill for grinding. The hydrocyclone classifies the slurry to obtain underflow sand and overflow slurry with a -200 mesh content of ≥85%. The underflow sand is returned to the ball mill for grinding. 3) Pump the overflow slurry to the flotation cell, add a 20% sodium carbonate solution to adjust the pH of the overflow slurry to 9.0, start stirring, add quartz inhibitor, calcium magnesium gangue inhibitor, fluorocarbon cerium ore collector and frother, aerate and float, turn on the froth scraper, continuously scrape off and collect the floating froth to obtain rough concentrate. 4) Dilute the crude concentrate with water to a liquid-to-solid ratio of 5:1, pump it into the cleaning tank, add quartz inhibitor, aerate and float, collect the floating foam in the cleaning tank, and obtain concentrate slurry. 5) Dilute the concentrate slurry with water or concentrate it under vacuum to adjust the concentrate slurry concentration to 50%. Add the concentrate slurry with the adjusted concentration to a planetary ball mill for grinding. Set the ball-to-material ratio to 10:1, filter, and dry to obtain activated mineral powder. S2, extractant P507 and kerosene were mixed in equal proportions to prepare a blank organic phase. The blank organic phase was then saponified with 30% (w / w) liquid alkali, and the degree of saponification was controlled at 0.8-1.2 mol / L to obtain the saponified organic phase. S3. Rare earth chloride solution and saponified organic phase are injected into the extraction tank at a ratio of 1:

3. The temperature is controlled at 25°C. After multi-stage countercurrent extraction, the phases are separated by standing to obtain a lanthanum, cerium, praseodymium, and neodymium mixed solution and a loaded organic phase with medium and heavy rare earths. The loaded organic phase is subjected to multi-stage back-extraction with a 20% hydrochloric acid solution to obtain a medium and heavy rare earth solution and a regenerated organic phase. S4. The lanthanum, cerium, praseodymium, and neodymium mixture and the saponified organic phase were injected into the extraction tank at a ratio of 1:

8. The temperature was controlled at 60°C. After multi-stage countercurrent extraction, the phases were separated by standing to obtain the organic phase loaded with praseodymium and neodymium and the lanthanum and cerium chloride solution. S5. At a controlled temperature of 60℃, the organic phase loaded with praseodymium and neodymium is subjected to multi-stage countercurrent washing with a 20% hydrochloric acid solution to obtain the purified first loaded organic phase and washing waste liquid. S6. The first loaded organic phase and 20% hydrochloric acid solution were injected into a pure neodymium tank at a ratio of 8:

1. The temperature was controlled at 60°C. After multi-stage countercurrent extraction and static separation, the organic phase loaded with neodymium and the praseodymium chloride solution were obtained. S7. At a controlled temperature of 60℃, the neodymium-loaded organic phase was subjected to multi-stage countercurrent washing with a 20% hydrochloric acid solution to obtain a purified second loaded organic phase and washing waste liquid. S8. The second loaded organic phase enters the multi-stage back-extraction section, where neodymium is transferred from the organic phase to the aqueous phase, resulting in a neodymium chloride solution and the regenerated organic phase. S9. According to the molar ratio of rare earth ions to oxalic acid of 1:1.2, 10% oxalic acid solution was slowly added to neodymium chloride solution, praseodymium-neodymium chloride solution, and lanthanum-cerium chloride solution, respectively. Stirring was started, the temperature was raised to 70°C, and the mixture was stirred at a constant temperature for 2 hours. After stirring was turned off, the mixture was allowed to stand for 4 hours to obtain rare earth oxalate precipitate. The rare earth oxalate precipitate was vacuum filtered, and the filter cake was washed with deionized water until the filtrate was neutral. The washed filter cake was sent to a calcination furnace and calcined at a constant temperature of 850°C for 4 hours. After calcination, the mixture was cooled to room temperature with the furnace and the rare earth oxide product was obtained.

2. The rare earth extraction and separation process according to claim 1, characterized in that: The quartz inhibitor is water glass, and the addition amount is 200g / t of raw ore.

3. The rare earth extraction and separation process according to claim 1, characterized in that: The calcium magnesium gangue inhibitor is composed of sodium hexametaphosphate and sodium citrate in a mass ratio of 1:1, and the addition amount is 150g / t of raw ore.

4. The rare earth extraction and separation process according to claim 1, characterized in that: The fluorocarbon cerium ore collector is a compound of isohydroxamic acid and oleic acid in a mass ratio of 3:1, and the addition amount is 80g / t of raw ore.

5. The rare earth extraction and separation process according to claim 1, characterized in that: The foaming agent is pine oil, and the addition amount is 20g / t of raw ore.

6. The rare earth extraction and separation process according to claim 1, characterized in that, The preparation process of alkaline pressure boiling oxidation includes: 1) Add activated mineral powder and 50% NaOH solution at a weight ratio of 1:0.8-1.2 to the reactor. Add 3wt% sodium carbonate based on the amount of NaOH solution used. Start stirring at 300 r / min and heat to 85℃ for 30 min for pretreatment. 2) After the pretreatment is completed, oxygen-enriched air is introduced to a pressure of 1.2 MPa, the temperature is raised to 160°C, the reaction is maintained for 4 hours, the temperature is lowered to 80°C and the pressure is released to atmospheric pressure. The slurry is discharged through the bottom valve to the plate and frame filter press for filtration to obtain a filter cake rich in rare earth hydroxides.

7. The rare earth extraction and separation process according to claim 6, characterized in that, The preparation process of the roasting transformation includes: The filter cake obtained by alkaline pressure boiling oxidation was washed with water at 80℃ until the pH of the filtrate was ≤8.

5. It was then fed into a kiln via a screw conveyor and roasted at 700℃ for 2 hours under air conditions. After cooling to room temperature, roasted mineral powder rich in rare earth oxides was obtained.

8. The rare earth extraction and separation process according to claim 7, characterized in that, The preparation process of the optimal solvent leaching includes: The roasted ore powder is mixed with water to a slurry concentration of 35%–45%. A 10% hydrochloric acid solution and ammonium sulfate are added, with the amount of hydrochloric acid solution being 1.2 times the mass of the roasted ore powder and the amount of ammonium sulfate being 1 wt% of the mass of the roasted ore powder. The temperature is raised to 60°C and the reaction is maintained for 2 hours. The mixture is then filtered to obtain a superior solution and a superior slag.

9. The rare earth extraction and separation process according to claim 8, characterized in that, The preparation process of the purification solution includes: 1) Add a 6 mol / L hydrochloric acid solution to the superior slag, with a liquid-to-solid ratio of 3:1, add a 5% hydrogen peroxide solution at a rate of 1.5 L / kg of superior slag, heat to 85℃, stir and react for 3 hours, filter, and combine the filtrate with the superior solution to obtain the leachate. 2) Add 20% hydrogen peroxide to the leachate, at a volume of 1.5 wt% of the leachate, oxidize for 20 min, add 20% NaOH solution to adjust the pH of the system to 2, add 0.1 wt% polyacrylamide of the total mass of the leachate, stir for 30 min at a speed of 150 r / min, let stand for 1 h to settle, filter out the precipitate, then adjust the pH to 3.5 with 10% ammonia solution, stir for 40 min, filter, and obtain the purified solution.

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