Method for extracting and separating rare earth from rare earth-containing phosphorite
By treating rare earth phosphate rock with phosphoric acid and sulfuric acid solutions, and taking advantage of the differences in element occurrence and kinetics, a highly efficient separation of rare earth elements and phosphorus can be achieved. This solves the problem of the difficulty in extracting rare earth elements from rare earth phosphate rock in existing technologies and is suitable for large-scale industrial applications.
Patent Information
- Application Number
- CN202511208517.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-08-27
- Publication Date
- 2025-11-21
AI Technical Summary
Existing technologies make it difficult to efficiently extract and separate rare earth elements from rare earth phosphate rock, and existing wet-process phosphoric acid production processes are incompatible with rare earth utilization, leading to resource waste and environmental impact.
By using phosphoric acid solution in short contact with rare earth phosphate rock and then adding sulfuric acid solution for treatment, the rare earth elements are selectively introduced into the liquid phase by taking advantage of the differences in the occurrence forms and extraction kinetics of rare earth and calcium impurities. Through reaction with calcium fluorophosphate, the extraction of P2O5 is enhanced and calcium dissolution is inhibited, thus achieving efficient separation of rare earth and phosphorus.
It achieves high-efficiency extraction rates of rare earth elements and phosphorus, with a simple process, low cost, good controllability, and suitability for large-scale industrial production, while taking into account the comprehensive utilization of rare earth elements and phosphorus.
Smart Images
Figure HDA0005568404240000011
Abstract
Description
Technical Field
[0001] This invention belongs to the field of rare earth phosphate rock extraction and separation technology, and relates to a method for extracting and separating rare earths from rare earth phosphate rock. Background Technology
[0002] Phosphorus and rare earth elements are both important strategic mineral resources. In rare earth phosphate mines, the two often occur together. If they can be comprehensively utilized, it will be of great significance to related industries. Conversely, it will lead to serious waste of resources and even environmental impact.
[0003] However, due to the significant differences in the content and basic properties of phosphorus and rare earth elements, and the relatively low rare earth content in rare earth phosphate rock compared to other rare earth minerals, simultaneously extracting and separating rare earth elements while utilizing phosphorus on a large scale is a challenging task. Existing methods primarily focus on phosphorus utilization, with the production of wet-process phosphoric acid as the primary objective, while the extraction of rare earth elements remains low.
[0004] Therefore, finding a more suitable method to solve the above-mentioned problems in the utilization of rare earths in existing rare earth phosphate mines, and developing a method for extracting and separating rare earths from rare earth phosphate mines in combination with wet-process phosphoric acid production, has become one of the urgent problems to be solved by many front-line researchers in the industry. Summary of the Invention
[0005] In view of this, the technical problem to be solved by the present invention is to provide a method for extracting and separating rare earth elements from rare earth-containing phosphate rock. The present invention uses a phosphoric acid solution to treat the rare earth phosphate rock in a short-contact manner, utilizing the differences in the occurrence forms and extraction kinetics of rare earth elements and impurity elements such as calcium, allowing rare earth elements to selectively and preferentially enter the liquid phase, resulting in a rare earth-poor solid phase, thus achieving efficient extraction of rare earth elements and phosphorus. The method for extracting and separating rare earth elements provided by the present invention has excellent extraction rates, and the process is simple, the conditions are mild, and the controllability is good, making it more suitable for promotion and application in large-scale industrial production.
[0006] This invention provides a method for extracting and separating rare earth elements from rare earth-containing phosphate rock, comprising the following steps:
[0007] 1) Mix rare earth phosphate rock with phosphoric acid solution, leach acid for a short time, add sulfuric acid solution to continue leaching, and then filter to separate filtrate A and filter cake B;
[0008] The short-time acid leaching time is 15 to 30 minutes;
[0009] The temperature for the short-time acid leaching is 80–90°C;
[0010] 2) Return a portion of the filtrate A obtained in the above steps to step (1), and the other portion of the filtrate A is the product after the rare earth is extracted and separated.
[0011] Preferably, the rare earth-containing phosphate rock comprises, by mass content:
[0012] CaO: 40%–60%, P2O5: 20%–35%, SiO2: 3%–4%, MgO: 1.2%–12.5%, and total rare earth content: 500–2000 ppm.
[0013] Preferably, the phosphoric acid solution contains 25% to 40% P2O5 by mass.
[0014] Preferably, the mass ratio of the phosphoric acid solution to the rare earth phosphate rock is (5-10):1.
[0015] Preferably, the sulfuric acid solution has a mass concentration of 95% to 98%.
[0016] Preferably, the ratio of the sulfuric acid solution to the rare earth phosphate rock is (1-1.1):1, based on the molar amount of SO3 in the sulfuric acid solution and the molar amount of CaO in the rare earth phosphate rock.
[0017] Preferably, the filtration and separation method includes one or more of vacuum filtration, pressure filtration, and centrifugal filtration.
[0018] Preferably, the ratio of the mass of rare earth elements in the product after rare earth extraction to the total mass of rare earth elements in the rare earth-containing phosphate rock is 50% to 95%.
[0019] Preferably, the filtrate A returned from step (1) is used as a phosphoric acid solution;
[0020] The product obtained after the rare earth is extracted and separated is used to process and produce phosphoric acid and / or rare earth products.
[0021] Preferably, the mass ratio of one portion of filtrate A to the other portion of filtrate A is (4-9):1;
[0022] The filter cake B is specifically phosphogypsum.
[0023] This invention provides a method for extracting and separating rare earth elements from rare earth-containing phosphate rock, comprising the following steps: first, mixing the rare earth-containing phosphate rock with a phosphoric acid solution, followed by short-term acid leaching, then adding a sulfuric acid solution for further leaching, and finally filtering to obtain filtrate A and filter cake B; the short-term acid leaching time is 15-30 minutes; the short-term acid leaching temperature is 80-90℃; finally, a portion of filtrate A obtained in the above steps is returned to step (1), and the other portion of filtrate A is the product after rare earth extraction and separation. Compared with the prior art, this invention, based on a full understanding of the migration patterns of phosphorus, rare earth elements, and other associated elements in wet-process phosphoric acid production, creatively designs a method for extracting and separating rare earth elements from rare earth phosphate rock that is combined with wet-process phosphoric acid production, in order to solve the problems that existing wet-process phosphoric acid production processes do not consider rare earth utilization and that current rare earth extraction methods are incompatible with wet-process phosphoric acid production.
[0024] The present invention provides a method for extracting and separating rare earth elements from rare earth phosphate rock. This method uses a phosphoric acid solution to treat the rare earth phosphate rock in a short-contact manner. Utilizing the differences in the occurrence forms and extraction kinetics of rare earth elements and impurities such as calcium, rare earth elements selectively and preferentially enter the liquid phase, resulting in a rare earth-poor solid phase. Then, taking advantage of the higher reactivity of sulfuric acid than phosphoric acid, it preferentially reacts with calcium fluorophosphate, enhancing P2O5 extraction and inhibiting calcium dissolution, thereby increasing the P2O5 extraction rate and preventing rare earth elements from passing through with calcium. 2+ The exchange returns to the solid phase, ultimately achieving efficient extraction of both rare earth elements and phosphorus within the wet phosphoric acid process framework. This approach is characterized by low cost and ease of implementation, and has broad application prospects.
[0025] This invention utilizes the differences in the occurrence forms and extraction kinetics of rare earth and calcium impurity elements, as well as the higher reactivity of sulfuric acid compared to phosphoric acid, to achieve selective separation of rare earth and phosphoric acid elements from impurity elements without introducing new material into wet phosphoric acid production. It takes into account the efficient comprehensive utilization of rare earth and phosphorus, has excellent extraction rate, and is simple, low-cost, controllable, and easy to implement, making it more suitable for promotion and application in large-scale industrial production. Attached Figure Description
[0026] Figure 1 This is a simplified schematic diagram of the process flow for extracting and separating rare earth elements from rare earth-containing phosphate rock, provided by the present invention. Detailed Implementation
[0027] To further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, and not for limiting the scope of the claims.
[0028] There are no particular restrictions on the source of any raw materials used in this invention; they can be purchased from the market or prepared using conventional methods known to those skilled in the art.
[0029] The purity of all raw materials used in this invention is not particularly limited. However, this invention preferably uses industrial-grade pure or conventionally pure materials used in the production of phosphoric acid from rare earth phosphate rock using the wet process.
[0030] This invention provides a method for extracting and separating rare earth elements from rare earth-containing phosphate rock, comprising the following steps:
[0031] 1) Mix rare earth phosphate rock with phosphoric acid solution, leach acid for a short time, add sulfuric acid solution to continue leaching, and then filter to separate filtrate A and filter cake B;
[0032] The short-time acid leaching time is 15 to 30 minutes;
[0033] The temperature for the short-time acid leaching is 80–90°C;
[0034] 2) Return a portion of the filtrate A obtained in the above steps to step (1), and the other portion of the filtrate A is the product after the rare earth is extracted and separated.
[0035] This invention first mixes rare earth phosphate rock with phosphoric acid solution, then leaches it with acid for a short time, and then adds sulfuric acid solution to continue leaching. Finally, the mixture is filtered to obtain filtrate A and filter cake B.
[0036] In this invention, the short-time acid leaching time is 15-30 minutes, or 18-27 minutes, or 21-24 minutes.
[0037] In this invention, the temperature of the short-time acid leaching is 80-90°C, or it can be 82-88°C or 84-86°C.
[0038] In this invention, the rare earth-containing phosphate rock preferably comprises, by mass content:
[0039] CaO: 40%–60%, P2O5: 20%–35%, SiO2: 3%–4%, MgO: 1.2%–12.5%, and total rare earth content: 500–2000 ppm, more preferably CaO: 44%–56%, P2O5: 23%–32%, SiO2: 3.2%–3.8%, MgO: 3%–10%, and total rare earth content: 800–1700 ppm, more preferably CaO: 48%–52%, P2O5: 26%–29%, SiO2: 3.4%–3.6%, MgO: 5%–8%, and total rare earth content: 1100–1400 ppm.
[0040] In this invention, the mass content of P2O5 in the phosphoric acid solution is preferably 25% to 40%, more preferably 28% to 37%, and even more preferably 31% to 34%.
[0041] In this invention, the mass ratio of the phosphoric acid solution to the rare earth phosphate rock is preferably (5-10):1, more preferably (6-9):1, and even more preferably (7-8):1.
[0042] In this invention, the mass concentration of the sulfuric acid solution is preferably 95% to 98%, more preferably 95.5% to 97.5%, and even more preferably 96% to 97%.
[0043] In this invention, the ratio of the sulfuric acid solution to the rare earth phosphate rock, based on the molar amount of SO3 in the sulfuric acid solution and the molar amount of CaO in the rare earth phosphate rock, is preferably (1-1.1):1, more preferably (1.02-1.08):1, and even more preferably (1.04-1.06):1.
[0044] In this invention, the mixing reaction time is preferably 1 to 4 hours, more preferably 1.5 to 3.5 hours, and even more preferably 2 to 3 hours.
[0045] In this invention, the temperature of the mixing reaction is preferably 70-95°C, more preferably 75-90°C, and even more preferably 80-85°C.
[0046] In this invention, the filtration and separation method preferably includes one or more of vacuum filtration, pressure filtration and centrifugal filtration, and more preferably vacuum filtration, pressure filtration or centrifugal filtration.
[0047] In this invention, the ratio of the mass of rare earth elements in the product after rare earth extraction to the total mass of rare earth elements in the rare earth-containing phosphate rock is 50%–95%, more preferably 60%–85%, and even more preferably 70%–75%. That is, the extraction rate of rare earth elements is preferably 50%–95%.
[0048] Finally, a portion of the filtrate A obtained in the above steps is returned to step (1), and the other portion of the filtrate A is the product after the rare earth is extracted and separated.
[0049] In this invention, the filtrate A from the return step (1) is preferably a phosphoric acid solution.
[0050] In this invention, the product obtained after the extraction and separation of rare earth elements is specifically a product rich in rare earth elements and phosphorus. It is preferably used for processing into phosphoric acid and / or rare earth products, and more preferably for producing phosphoric acid and rare earth products. The processing method for producing rare earth products includes one or more steps such as selective precipitation, ion exchange, and solvent extraction to obtain the rare earth products.
[0051] This invention provides a method for extracting and separating rare earth elements from rare earth-containing phosphate rock, which can be a method for simultaneously extracting and separating rare earth elements and phosphorus from rare earth-containing phosphate rock. The product after rare earth extraction and separation is a product rich in rare earth elements and phosphorus after rare earth extraction and separation (removal of impurities).
[0052] In this invention, the mass ratio of one part of filtrate A to another part of filtrate A is (4-9):1, more preferably (5-8):1, and even more preferably (6-7):1.
[0053] In this invention, the filter cake B is preferably phosphogypsum.
[0054] This invention provides a complete and detailed overall technical solution to better ensure the stable operation of the rare earth extraction and separation process from rare earth phosphate rock, and further improve the separation and extraction efficiency of rare earth and phosphorus elements from rare earth phosphate rock. Specifically, the method for extracting and separating rare earth from rare earth phosphate rock may include the following:
[0055] A method for extracting and separating rare earth elements from rare earth phosphate rock includes the following steps:
[0056] (1) Use phosphoric acid solution to contact rare earth phosphate rock at a certain mass ratio, leach at 80-90 degrees Celsius for 15 to 30 minutes, then add a certain amount of sulfuric acid solution and continue leaching for 60 to 120 minutes, then filter to separate and obtain filtrate A and filter cake B.
[0057] (2) Filtrate A is divided into two parts. The first part is used as the phosphoric acid solution in step (1), and the second part is further processed to produce phosphoric acid and rare earth products.
[0058] (3) Filter cake B was treated as phosphogypsum.
[0059] Specifically, in step (1), the content of P2O5 in the phosphoric acid solution is 25-40%, and the mass ratio of the phosphoric acid solution to rare earth phosphate rock is 5-10:1.
[0060] Specifically, the concentration of the sulfuric acid solution in step (2) is 95%-98%, and the total molar amount of SO3 it contains is 1 to 1.1 times the total molar amount of CaO in the rare earth phosphate rock in step (1).
[0061] Specifically, the filtration and separation methods include vacuum filtration, pressure filtration, and centrifugal filtration.
[0062] Specifically, in step (4), the ratio of the first part to the second part is 4-9:1.
[0063] See Figure 1 , Figure 1 This is a simplified schematic diagram of the process flow for extracting and separating rare earth elements from rare earth-containing phosphate rock, provided by the present invention.
[0064] The present invention provides a method for extracting and separating rare earth elements from rare earth phosphate rock. This method uses a phosphoric acid solution to treat the rare earth phosphate rock in a short-contact manner. Utilizing the differences in the occurrence forms and extraction kinetics of rare earth elements and impurities such as calcium, rare earth elements selectively and preferentially enter the liquid phase, resulting in a rare earth-poor solid phase. Then, taking advantage of the higher reactivity of sulfuric acid than phosphoric acid, it preferentially reacts with calcium fluorophosphate, enhancing P2O5 extraction and inhibiting calcium dissolution, thereby increasing the P2O5 extraction rate and preventing rare earth elements from passing through with calcium. 2+ The exchange returns to the solid phase, ultimately achieving efficient extraction of both rare earth elements and phosphorus within the wet phosphoric acid process framework. This approach is characterized by low cost and ease of implementation, and has broad application prospects.
[0065] This invention utilizes the differences in the occurrence forms and extraction kinetics of rare earth and calcium impurity elements, as well as the higher reactivity of sulfuric acid compared to phosphoric acid, to achieve selective separation of rare earth and phosphoric acid elements from impurity elements without introducing new material into wet phosphoric acid production. It takes into account the efficient comprehensive utilization of rare earth and phosphorus, has excellent extraction rate, and is simple, low-cost, controllable, and easy to implement, making it more suitable for promotion and application in large-scale industrial production.
[0066] To further illustrate the present invention, the following describes in detail a method for extracting and separating rare earth elements from rare earth-containing phosphate rock, provided by the present invention, in conjunction with embodiments. However, it should be understood that these embodiments are implemented under the premise of the technical solution of the present invention, and provide detailed implementation methods and specific operating procedures. They are only for further illustrating the features and advantages of the present invention, and are not intended to limit the scope of the claims of the present invention. The scope of protection of the present invention is not limited to the following embodiments.
[0067] Example 1
[0068] The rare earth-containing phosphate rock, by mass content, has the following composition: CaO, 50%; P2O5, 28%; SiO2, 3.5%; MgO, 6%; and a total rare earth content of 1260 ppm.
[0069] Take 50g of rare earth phosphate rock and add 500g of phosphoric acid solution with a P2O5 content of 35%. Contact the two at 80 degrees for 15 minutes. Then add 45g of 98% sulfuric acid to the system and continue leaching for 120 minutes. Filter and separate to obtain filtrate A and filter cake B.
[0070] The rare earth element and P2O5 contents in filtrate A were analyzed, and the rare earth element and P2O5 contents in rare earth phosphate rock were also analyzed. The extraction rates of rare earth elements and P2O5 were calculated to be 73% and 96%, respectively.
[0071] Example 2
[0072] The rare earth-containing phosphate rock, by mass content, has the following composition: CaO, 51%; P2O5, 27%; SiO2, 3.6%; MgO, 6%; and a total rare earth content of 1150 ppm.
[0073] Take 50g of rare earth phosphate rock and add 500g of phosphoric acid solution with a P2O5 content of 40%. Contact the two at 80 degrees for 20 minutes. Then add 45g of 98% sulfuric acid to the system and continue leaching for 90 minutes. Filter and separate to obtain filtrate A and filter cake B.
[0074] The rare earth element and P2O5 contents in filtrate A were analyzed, and the rare earth element and P2O5 contents in rare earth phosphate rock were also analyzed. The extraction rates of rare earth elements and P2O5 were calculated to be 72% and 95%, respectively.
[0075] Example 3
[0076] The rare earth-containing phosphate rock, by mass content, has the following composition: CaO, 53%; P2O5, 26%; SiO2, 3.6%; MgO, 5%; and a total rare earth content of 1150 ppm.
[0077] Take 48g of rare earth phosphate rock and add 500g of phosphoric acid solution with a P2O5 content of 38%. Contact the two at 80 degrees for 30 minutes. Then add 50g of 95% sulfuric acid to the system and continue leaching for 120 minutes. Filter and separate to obtain filtrate A and filter cake B.
[0078] The rare earth element and P2O5 contents in the filtrate were analyzed, and the rare earth element and P2O5 contents in the rare earth phosphate rock were also analyzed. The extraction rates of rare earth elements and P2O5 were calculated to be 70% and 97%, respectively.
[0079] Example 4
[0080] The rare earth-containing phosphate rock, by mass content, has the following composition: CaO, 48%; P2O5, 29%; SiO2, 3.6%; MgO, 5%; and a total rare earth content of 1320 ppm.
[0081] Take 55g of rare earth phosphate rock and add 500g of phosphoric acid solution with a P2O5 content of 39%. Contact the two at 90 degrees for 15 minutes. Then add 50g of 97% sulfuric acid to the system and continue leaching for 70 minutes. Filter and separate to obtain filtrate A and filter cake B.
[0082] The rare earth element and P2O5 content in the filtrate were analyzed, and the rare earth elements and P2O5 in the rare earth phosphate rock were also analyzed. The extraction rates of rare earth elements and P2O5 were calculated to be 73% and 95%, respectively.
[0083] The present invention provides a detailed description of a method for extracting and separating rare earth elements from rare earth-containing phosphate rock. Specific examples have been used to illustrate the principles and implementation methods of the invention. The descriptions of these embodiments are merely for the purpose of helping to understand the method and its core ideas, including the best mode, and also to enable any person skilled in the art to practice the invention, including manufacturing and using any device or system, and implementing any combined method. It should be noted that those skilled in the art can make various improvements and modifications to the invention without departing from its principles, and these improvements and modifications also fall within the scope of protection of the claims. The scope of protection of this patent is defined by the claims and may include other embodiments that can be conceived by those skilled in the art. If these other embodiments have structural elements that are not different from the wording of the claims, or if they include equivalent structural elements that are not substantially different from the wording of the claims, then these other embodiments should also be included within the scope of the claims.
Claims
1. A method for extracting and separating rare earth elements from rare earth-containing phosphate rock, characterized in that, Includes the following steps: 1) Mix rare earth phosphate rock with phosphoric acid solution, leach acid for a short time, add sulfuric acid solution to continue leaching, and then filter to separate filtrate A and filter cake B; The short-time acid leaching time is 15 to 30 minutes; The temperature for the short-time acid leaching is 80–90°C; 2) Return a portion of the filtrate A obtained in the above steps to step (1), and the other portion of the filtrate A is the product after the rare earth is extracted and separated.
2. The method according to claim 1, characterized in that, The rare earth-containing phosphate rock, by mass content, includes: CaO: 40%–60%, P2O5: 20%–35%, SiO2: 3%–4%, MgO: 1.2%–12.5%, and total rare earth content: 500–2000 ppm.
3. The method according to claim 1, characterized in that, The phosphoric acid solution contains 25% to 40% P2O5 by mass.
4. The method according to claim 1, characterized in that, The mass ratio of the phosphoric acid solution to the rare earth-containing phosphate rock is (5-10):
1.
5. The method according to claim 1, characterized in that, The sulfuric acid solution has a mass concentration of 95% to 98%.
6. The method according to claim 1, characterized in that, The sulfuric acid solution and the rare earth phosphate rock are in a ratio of (1-1.1):1, based on the molar amount of SO3 in the sulfuric acid solution and the molar amount of CaO in the rare earth phosphate rock.
7. The method according to claim 1, characterized in that, The filtration and separation methods include one or more of vacuum filtration, pressure filtration, and centrifugal filtration.
8. The method according to claim 1, characterized in that, The ratio of the mass of rare earth elements in the product after rare earth extraction and separation to the total mass of rare earth elements in the rare earth-containing phosphate rock is 50% to 95%.
9. The method according to claim 1, characterized in that, The filtrate A returned from step (1) is used as a phosphoric acid solution; The product obtained after the rare earth is extracted and separated is used to process and produce phosphoric acid and / or rare earth products.
10. The method according to claim 1, characterized in that, The mass ratio of one portion of filtrate A to the other portion of filtrate A is (4-9):1; The filter cake B is specifically phosphogypsum.