METHODS FOR REDUCING ALUMINUM IMPURITY DISSOLUTION FROM IONIC RARE EARTH ORE
Patent Information
- Authority / Receiving Office
- VN · VN
- Patent Type
- Applications
- Current Assignee / Owner
- GRIREM ADVANCED MATERIALS CO LTD
- Filing Date
- 2024-02-27
- Publication Date
- 2026-07-01
AI Technical Summary
During the leaching process of ionic rare earth ore, the leaching amount of impurity aluminum is relatively large, resulting in increased environmental pollution and production costs.
The leachate solution is segmented leaching-centrifugal extraction and enrichment method. By adding high- and low-concentration leaching solution at a time, the pH value of the leaching solution is controlled, the morphological conversion of hydroxyl adsorbed aluminum and the exchange and desorption of ion-exchange aluminum is inhibited, and the leaching of impurity aluminum is reduced through the preparation of aluminum-containing raffinate.
It effectively reduces the leaching amount of impurity aluminum, reduces the consumption and production costs of leaching agents, and avoids pollution of radioactive waste slag and ammonia nitrogen wastewater, reducing the environmental protection pressure of mining enterprises.
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Abstract
Description
A method for reducing the leaching of impurity aluminum in ionic rare earth ores
[0001] Cross-references
[0002] This application is based on the Chinese patent application with application number 2023114223771 and application date October 30, 2023, and claims the priority of the Chinese patent application. The entire content of the Chinese patent application is hereby introduced into this application as a reference. Technical Field
[0003] The present invention relates to the technical field of rare earth extraction and enrichment, and in particular to a method for reducing the leaching of impurity aluminum in ionic rare earth ores. Background Art
[0004] Rare earth elements, especially medium and heavy rare earth elements, are hailed as "vitamins of modern industry" and a "treasure trove of new materials." They are widely used in strategic emerging industries, defense, and military applications, and are essential core building blocks for the preparation of high-end magnetic materials, laser crystals, and other applications. Ionic rare earth ores are primarily distributed in seven southern provinces of my country: Jiangxi, Guangdong, Guangxi, Hunan, Fujian, Yunnan, and Zhejiang. Medium and heavy rare earth elements account for 40% to 90% of the total, making them a valuable strategic resource in my country.
[0005] The rare earth elements in ionic rare earth ores are primarily adsorbed in a hydrated ionic state on clay minerals such as kaolinite, resulting in extremely low rare earth grades (only 0.03% to 0.1% REO). my country has pioneered a unique process for producing rare earth concentrate using ammonium sulfate leaching followed by ammonium bicarbonate precipitation enrichment, enabling the large-scale development and utilization of ultra-low-grade rare earth ores. However, the process is lengthy and the rare earth yield is low. Producing one ton of ionic rare earth concentrate (measured in REO) consumes over 10 tons of ammonium salt, a 3-4-fold excess, generating large amounts of ammoniacal nitrogen wastewater and radioactive residue. Furthermore, the rare earth leachate is neutralized and decontaminated with ammonium bicarbonate, followed by precipitation and enrichment of the rare earth elements. Approximately 97% of the impure aluminum is hydrolyzed into the decontamination residue, while the remaining approximately 3% is incorporated into the rare earth carbonate product. The precipitation mother liquor contains virtually no aluminum. Since there is a certain solid-liquid distribution ratio of impure aluminum between clay minerals such as kaolinite and the leaching agent solution, when the precipitation mother liquor that does not contain aluminum is returned to the mine for leaching, the impure aluminum is continuously leached, and the amount of impure aluminum leached increases significantly.
[0006] According to the Groundwater Quality Standard (GB / T14848-2017), the concentration limits of ammonia nitrogen and aluminum in Class III groundwater are 0.5 mg / L and 0.2 mg / L respectively; according to the Surface Water Environmental Quality Standard (GB3838-2002), the concentration limit of ammonia nitrogen in Class III surface water is 1.0 mg / L. The concentration limit requirement for aluminum is not directly specified, but the pH is required to be 6-9, under which the concentration of aluminum is <0.1 mg / L. It can be seen that the concentration limit requirements for aluminum in surface / groundwater are even stricter than those for ammonia nitrogen. The fundamental reason is that: (1) Affected by soil acidification, it can promote the active aluminum (Al2O3) in the soil. 3+ 、Al(OH) 2+ 、Al(OH)2 + ) dissolves, seriously inhibiting the root growth of plants and affecting their absorption of elements such as calcium and magnesium; (2) active aluminum in the soil enters the water body and can react with F - OH - etc. to form [AlF6] 3- 、Al(OH)4 - Especially when pH < 5.5, F in water - Almost all of it generates [AlF6] 3- , causing water pollution; (3) Excessive intake of aluminum by the human body can easily lead to neuronal apoptosis, which in turn causes Alzheimer's disease. It can also inhibit bone growth, causing osteoporosis, osteomalacia and other diseases. Therefore, minimizing the leaching of impurity aluminum during the leaching process of ionic rare earth ores is of great significance to both the extraction and enrichment technology of ionic rare earth ores and the protection of the mining environment.
[0007] In order to solve the above problems, the prior art proposes to introduce an inhibitor such as hexamethylenetetramine, hexamethylenetetramine, formates, acetates, tartaric acid, or a composite cationic surfactant (containing hexadecyltrimethylammonium bromide and dodecyltrimethylammonium bromide) into the process of leaching ionic rare earth ores with ammonium salt or magnesium salt solutions. The inhibitor reacts with the impurity aluminum in the ionic rare earth ores through chemical reactions such as complexation, thereby retaining the impurity aluminum in the ionic rare earth ores and thus achieving the purpose of reducing the leaching of the impurity aluminum. In addition, a method of adding a leaching aid containing carboxymethyl chitosan, modified starch, polyhydroxy alcohol, and potassium acetate to the ammonium salt solution for leaching, as well as a method of performing staged leaching using an acetic acid solution (pH = 3-4), a magnesium salt, or a calcium salt solution, has also been proposed. These methods can also reduce the leaching of the impurity aluminum in the ionic rare earth ores to a certain extent.
[0008] However, in order to effectively reduce the leaching of impurity aluminum in ionic rare earth ores, the above method requires the introduction of a large amount of expensive organic reagents during the leaching process of ionic rare earth ores, resulting in a significant increase in leaching costs. At the same time, since the organic reagents are directly injected into the ionic rare earth ore body, it is easy to cause the COD of the surface / groundwater system in the mining area to exceed the standard, which has an adverse impact on the ecological environment of the mining area.
[0009] Summary of the Invention
[0010] The purpose of the embodiments of the present invention is to provide a method for reducing the leaching of impurity aluminum in ionic rare earth ores. By adopting segmented leaching and centrifugal extraction enrichment of a leaching agent solution, the form transformation of hydroxyl-adsorbed aluminum and the exchange and desorption of ion-exchange aluminum are suppressed from the source. Without affecting the rare earth leaching rate, the leaching amount of impurity aluminum is greatly reduced, and the leaching agent consumption and production costs are reduced.
[0011] To solve the above technical problems, an embodiment of the present invention provides a method for reducing the leaching of impurity aluminum in ionic rare earth ores, comprising the following steps:
[0012] sequentially leaching the ionic rare earth ore with a first leaching agent solution and a second leaching agent solution to obtain a rare earth leachate;
[0013] centrifugally extracting the rare earth leachate with an organic extractant to obtain a rare earth-loaded organic phase and an aluminum-containing raffinate;
[0014] The aluminum-containing raffinate is prepared to obtain a first leaching agent solution and a second leaching agent solution, and the ionic rare earth ore is leached;
[0015] The hydrogen ion concentration in the first lixiviant solution is 0.00001 mol / L to 0.001 mol / L, the hydrogen ion concentration in the second lixiviant solution is 0.001 mol / L to 0.02 mol / L, and the aluminum content in the rare earth leachate is 20 mg / L to 3000 mg / L.
[0016] Furthermore, in the first leaching agent solution, the hydrogen ion concentration is 0.0001 mol / L to 0.001 mol / L;
[0017] In the second leaching agent solution, the hydrogen ion concentration is 0.002 mol / L to 0.01 mol / L.
[0018] Furthermore, in the first leaching agent solution, the concentration of cations other than hydrogen ions and aluminum ions is 0.15 mol / L to 0.4 mol / L;
[0019] In the second leachate solution, the concentration of cations other than hydrogen ions and aluminum ions is 0.05 mol / L to 0.15 mol / L.
[0020] Furthermore, the first leaching agent solution and the second leaching agent solution respectively include at least one of magnesium sulfate, magnesium chloride, calcium chloride, sodium sulfate, sodium chloride, potassium chloride, potassium sulfate and ferrous sulfate.
[0021] Furthermore, the first leaching agent solution and the second leaching agent solution respectively include at least one of magnesium sulfate, magnesium chloride and calcium chloride.
[0022] Furthermore, in the first leachate solution and the second leachate solution, except for hydrogen ions and aluminum ions, the molar percentages of various cations are: magnesium ions 40% to 99%, calcium ions 1% to 55%, sodium ions, potassium ions and / or ferrous ions 0% to 50%.
[0023] Furthermore, the organic extractant is an acidic phosphorus extractant;
[0024] The concentration of the acidic phosphorus extractant is 0.5 mol / L to 1.5 mol / L.
[0025] Furthermore, the organic extractant includes at least one of P507, P204, P227, and Cyanex272.
[0026] Furthermore, the contact time between the organic extractant and the rare earth leaching solution is 5s to 60s.
[0027] Furthermore, the aluminum content in the aluminum-containing raffinate is 20 mg / L to 3000 mg / L.
[0028] The above technical solutions of the embodiments of the present invention have the following beneficial technical effects:
[0029] 1. By using a leaching method in which leaching agent solutions are added successively, the first leaching agent solution (high concentration leaching agent) is first used to leach the ionic rare earth ore, so that the rare earth in the ionic rare earth ore is exchanged and desorbed efficiently and quickly, while controlling the pH of the leaching solution at a high level to prevent the hydroxyl-adsorbed aluminum in the ionic rare earth ore from being converted into ion-exchange or water-soluble aluminum; then the second leaching agent solution (lower concentration leaching agent) is used to reduce leaching agent consumption, while controlling the pH of the leaching solution at a low level to prevent the rare earth ions exchanged and desorbed from being reversely adsorbed in the ionic rare earth ore.
[0030] 2. Through the leaching method of circulating leaching with aluminum-containing raffinate, due to the existence of a certain solid-liquid distribution ratio between impurity aluminum in clay minerals such as kaolinite and the leaching agent solution, when the aluminum-containing raffinate is circulated back to the mine for leaching, the exchange and desorption of ion-exchange aluminum in the ionic rare earth ore is greatly inhibited, thereby preventing the ion-exchange aluminum in the ionic rare earth ore from being exchanged and desorbed into water-soluble aluminum.
[0031] 3. By adopting the above-mentioned method of segmented leaching of the leaching agent solution and circulating leaching of the ore with the aluminum-containing raffinate, efficient and rapid leaching of rare earths is achieved, while avoiding the large-scale leaching of impurity aluminum caused by the transformation of the hydroxyl-adsorbed aluminum form and the exchange and desorption of ion-exchange aluminum. The leaching agent consumption is greatly reduced, and the production cost is significantly reduced.
[0032] 4. Utilizing a leaching agent solution staged leaching followed by centrifugal extraction and enrichment, this process eliminates the radioactive waste and ammonia nitrogen wastewater pollution associated with conventional inorganic salt leaching and precipitation enrichment processes, significantly reducing the environmental burden on ionic rare earth mining companies. Furthermore, this leaching agent solution staged leaching followed by centrifugal extraction and enrichment technology can be used to treat all minerals containing ionic rare earths, thus providing a wide range of applications. BRIEF DESCRIPTION OF THE DRAWINGS
[0033] FIG1 is a schematic diagram of the specific steps of a method for reducing leaching of aluminum impurities in ionic rare earth ores provided by an embodiment of the present invention;
[0034] FIG2 is a schematic diagram of a process flow of a method for reducing leaching of aluminum impurities in ionic rare earth ores provided in an embodiment of the present invention. DETAILED DESCRIPTION
[0035] To make the objectives, technical solutions, and advantages of the present invention more clearly understood, the present invention will be further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings. It should be understood that these descriptions are merely exemplary and are not intended to limit the scope of the present invention. In addition, in the following description, descriptions of well-known structures and technologies are omitted to avoid unnecessary confusion of the concepts of the present invention.
[0036] 1 and 2 , an embodiment of the present invention provides a method for reducing the leaching of aluminum impurities in ionic rare earth ores, comprising the following steps:
[0037] Step S1: sequentially using a first leaching agent solution and a second leaching agent solution to leach an ionic rare earth ore to obtain a rare earth leachate.
[0038] The invention adopts a treatment method of adding leaching agent solutions successively, wherein the first leaching agent solution (0.15 mol / L to 0.4 mol / L) is first used to leach the ionic rare earth ore, so that the rare earth in the ionic rare earth ore is efficiently and quickly exchanged and desorbed, while the pH value of the leaching solution is controlled to be relatively high (hydrogen ion concentration is 0.00001 mol / L to 0.001 mol / L) to prevent the hydroxyl-adsorbed aluminum in the ionic rare earth ore from being converted into ion-exchange or water-soluble aluminum; then, the second leaching agent solution (0.05 mol / L to 0.15 mol / L) is used to reduce the leaching agent consumption, while the pH value of the leaching solution is controlled to be relatively low (hydrogen ion concentration is 0.001 mol / L to 0.02 mol / L) to prevent the rare earth ions exchanged and desorbed from being reversely adsorbed in the ionic rare earth ore; and the segmented leaching of the above leaching agent solutions realizes efficient and rapid leaching of rare earth, while avoiding the large-scale leaching of impurity aluminum caused by the transformation of the hydroxyl-adsorbed aluminum.
[0039] Step S2, centrifugally extracting the rare earth leachate with an organic extractant to obtain a rare earth-loaded organic phase and an aluminum-containing raffinate.
[0040] The rare earth leachate contains rare earth ions, aluminum ions, leaching agent cations (such as Mg 2+ , Ca 2+ 、Na + , K + 、Fe 2+ The aluminum content is 20 to 3000 mg / L (calculated as alumina). An organic extractant is used for centrifugal extraction in an acidic system to achieve selective extraction and enrichment of rare earths, while the impurity aluminum is basically retained in the raffinate.
[0041] Step S3: The aluminum-containing raffinate is prepared to obtain a first leaching agent solution and a second leaching agent solution, and the ionic rare earth ore is leached.
[0042] During the leaching process of ionic rare earth ores, the concentration of ion exchange between the ion exchanger cations and the rare earth elements in the ionic rare earth ore typically remains lower in the rare earth leachate than in the ion exchanger solution. During centrifugal extraction and enrichment of the rare earth leachate, the ion exchanger cations are largely unextracted and remain in the aluminum-containing raffinate, but the pH of the raffinate decreases. Therefore, when the aluminum-containing raffinate is recycled back to the mine for leaching, the ion exchanger cation concentration and pH of the aluminum-containing raffinate must be adjusted to the desired ranges for the first and second ion exchanger solutions to ensure sufficient exchange and desorption of the rare earth elements from the ionic rare earth ore.
[0043] It should be noted that the hydroxyl adsorption state is mainly adsorbed on the surface of clay minerals in the form of inorganic hydroxyl compounds, while the ion exchange state is mainly adsorbed on the surface of clay minerals in the form of ions or hydrated ions.
[0044] Since there is a certain solid-liquid distribution ratio between impurity aluminum in clay minerals such as kaolinite and the leaching agent solution, when the aluminum-containing raffinate (aluminum content of 20-3000 mg / L, calculated as alumina) is prepared and circulated back to the mine for leaching, the exchange desorption of ion-exchange aluminum in the ionic rare earth ore is greatly suppressed, thereby avoiding the large-scale leaching of impurity aluminum caused by the desorption of ion-exchange aluminum. In addition, when the aluminum-containing raffinate is circulated back to the mine for leaching, the small amount of aluminum ions in the raffinate can also serve as a leaching agent, further reducing the consumption of leaching agent.
[0045] The hydrogen ion concentration in the first lixiviant solution is 0.00001 mol / L to 0.001 mol / L, the hydrogen ion concentration in the second lixiviant solution is 0.001 mol / L to 0.02 mol / L, and the aluminum content in the rare earth leachate is 20 mg / L to 3000 mg / L.
[0046] Furthermore, in the first lixiviant solution, the hydrogen ion concentration is preferably 0.0001 mol / L to 0.001 mol / L; in the second lixiviant solution, the hydrogen ion concentration is preferably 0.002 mol / L to 0.01 mol / L.
[0047] In addition, in the first lixiviant solution, the concentration of cations other than hydrogen ions and aluminum ions is 0.15 mol / L to 0.4 mol / L; in the second lixiviant solution, the concentration of cations other than hydrogen ions and aluminum ions is 0.05 mol / L to 0.15 mol / L.
[0048] Specifically, the first leaching agent solution and the second leaching agent solution respectively include at least one of magnesium sulfate, magnesium chloride, calcium chloride, sodium sulfate, sodium chloride, potassium chloride, potassium sulfate and ferrous sulfate.
[0049] Preferably, the first lixiviant solution and the second lixiviant solution respectively include at least one of magnesium sulfate, magnesium chloride and calcium chloride.
[0050] The present invention employs a staged leaching process using a magnesium salt-containing leachant solution and a circulating leaching process using an aluminum-containing raffinate, significantly reducing leachant consumption and production costs. This process, combined with staged leaching using a magnesium salt-containing leachant solution and centrifugal extraction and enrichment, eliminates the radioactive waste and ammonia nitrogen wastewater pollution associated with conventional inorganic salt leaching and precipitation enrichment processes, significantly alleviating the environmental burden on ionic rare earth mining companies.
[0051] According to the demand of ionic rare earth mine soil for nutrients such as magnesium and calcium, the ratio of magnesium, calcium, etc. in the first leaching agent solution and the second leaching agent solution is appropriately adjusted so that the tailings after leaching meet the soil nutrient requirements.
[0052] Furthermore, in the first leachate solution and the second leachate solution, except for hydrogen ions and aluminum ions, the molar percentages of various cations are: magnesium ions 40% to 99%, calcium ions 1% to 55%, sodium ions, potassium ions and / or ferrous ions 0% to 50%.
[0053] Optionally, the organic extractant is an acidic phosphorus extractant; the concentration of the acidic phosphorus extractant is 0.5 mol / L to 1.5 mol / L. Using an acidic phosphorus extractant, which is widely used in the rare earth industry, allows the centrifugal extraction process to be performed under acidic conditions, effectively avoiding problems such as emulsification and three-phase separation caused by the hydrolysis of impurities such as aluminum during conventional saponification extraction.
[0054] Optionally, the organic extractant is preferably at least one of P507, P204, P227, and Cyanex272.
[0055] Specifically, the contact time between the organic extractant and the rare earth leachate in step S2 is 5 to 60 seconds. Centrifugal extraction is performed using an acidic phosphorus extractant under acidic conditions, and the contact time between the organic extractant and the rare earth leachate is controlled to be 5 to 60 seconds. By utilizing the difference in extraction kinetics between rare earth and aluminum, the rare earth is efficiently extracted while the aluminum impurity is barely extracted and remains in the raffinate.
[0056] Specifically, the aluminum content in the aluminum-containing raffinate in step S2 is 20 mg / L to 3000 mg / L.
[0057] The present invention adopts the method of staged leaching of leaching agent solution and circulating leaching of ore by preparing aluminum-containing raffinate, thereby inhibiting the form transformation of hydroxyl-adsorbed aluminum and the exchange and desorption of ion-exchange aluminum from the source, and reducing the amount of impurity aluminum leached by more than 90% compared with the conventional inorganic salt leaching-precipitation enrichment process.
[0058] The technical solution of the present invention is further illustrated below through several comparative examples and several embodiments.
[0059] Example 1
[0060] The ionic rare earth ore has an ion-exchange rare earth grade of 0.05% and an ion-exchange aluminum grade of 0.035%. The ionic rare earth ore is leached using a first and then a second leachant solution. The first leachant solution has a hydrogen ion concentration of 0.00001 mol / L and a cation concentration of 0.20 mol / L, with MgSO4 as the primary leachant component. The second leachant solution has a hydrogen ion concentration of 0.01 mol / L and a cation concentration of 0.10 mol / L, with MgSO4 and CaCl2 as the primary leachants. The molar percentages of magnesium ions and calcium ions are 99% and 1%, respectively. The rare earth leachate obtained after treatment with the above leachants is centrifuged using an organic extractant to produce a rare earth-loaded organic phase and an aluminum-containing raffinate. The organic extractant was P507, the concentration of P507 was 1.0 mol / L, the volume flow ratio of P507 to rare earth leaching solution was 1:20, and the contact time was 15 seconds. The obtained aluminum-containing raffinate was prepared and recycled back to the leaching process.
[0061] After the above process, the rare earth leaching rate of the ionic rare earth ore is 95.1%, and the impurity aluminum leaching rate is 4.1%.
[0062] In addition, Comparative Examples 1 to 6 and Examples 2 to 41 are shown in Table 1a, Table 1b, and Table 1c.
[0063] Table 1a
[0064] Table 1b
[0065] Table 1c
[0066] The embodiment of the present invention aims to protect a method for reducing the leaching of impurity aluminum in ionic rare earth ores, comprising the following steps: sequentially leaching the ionic rare earth ore with a first leaching agent solution and a second leaching agent solution to obtain a rare earth leachate; centrifugally extracting the rare earth leachate with an organic extractant to obtain a rare earth-loaded organic phase and an aluminum-containing raffinate; blending the aluminum-containing raffinate to obtain a first leaching agent solution and a second leaching agent solution, and leaching the ionic rare earth ore; wherein the hydrogen ion concentration in the first leaching agent solution is 0.00001 mol / L to 0.001 mol / L, the hydrogen ion concentration in the second leaching agent solution is 0.001 mol / L to 0.02 mol / L, and the aluminum content in the rare earth leachate is 20 mg / L to 3000 mg / L. The above technical solution has the following effects:
[0067] 1. By using a leaching method in which leaching agent solutions are added successively, the first leaching agent solution (high concentration leaching agent) is first used to leach the ionic rare earth ore, so that the rare earth in the ionic rare earth ore is exchanged and desorbed efficiently and quickly, while controlling the pH of the leaching solution at a high level to prevent the hydroxyl-adsorbed aluminum in the ionic rare earth ore from being converted into ion-exchange or water-soluble aluminum; then the second leaching agent solution (lower concentration leaching agent) is used to reduce leaching agent consumption, while controlling the pH of the leaching solution at a low level to prevent the rare earth ions exchanged and desorbed from being reversely adsorbed in the ionic rare earth ore.
[0068] 2. Through the leaching method of circulating leaching with aluminum-containing raffinate, due to the existence of a certain solid-liquid distribution ratio between impurity aluminum in clay minerals such as kaolinite and the leaching agent solution, when the aluminum-containing raffinate is circulated back to the mine for leaching, the exchange and desorption of ion-exchange aluminum in the ionic rare earth ore is greatly inhibited, thereby preventing the ion-exchange aluminum in the ionic rare earth ore from being exchanged and desorbed into water-soluble aluminum.
[0069] 3. By adopting the above-mentioned method of segmented leaching of the leaching agent solution and circulating leaching of the ore with the aluminum-containing raffinate, efficient and rapid leaching of rare earths is achieved, while avoiding the large-scale leaching of impurity aluminum caused by the transformation of the hydroxyl-adsorbed aluminum form and the exchange and desorption of ion-exchange aluminum. The leaching agent consumption is greatly reduced, and the production cost is significantly reduced.
[0070] 4. Utilizing a leaching agent solution staged leaching followed by centrifugal extraction and enrichment, this process eliminates the radioactive waste and ammonia nitrogen wastewater pollution associated with conventional inorganic salt leaching and precipitation enrichment processes, significantly reducing the environmental burden on ionic rare earth mining companies. Furthermore, this leaching agent solution staged leaching followed by centrifugal extraction and enrichment technology can be used to treat all minerals containing ionic rare earths, thus providing a wide range of applications.
[0071] It should be understood that the above-described specific embodiments of the present invention are merely illustrative or illustrative of the principles of the present invention and do not constitute limitations of the present invention. Therefore, any modifications, equivalent substitutions, improvements, etc. made without departing from the spirit and scope of the present invention should be included within the scope of protection of the present invention. In addition, the appended claims are intended to cover all variations and modifications that fall within the scope and metes and bounds of the appended claims, or equivalents thereof.
Claims
1. A method for reducing the leaching of impurity aluminum in ionic rare earth ores, characterized in that: The steps include: Sequentially using a first leaching agent solution and a second leaching agent solution to leach the ionic rare earth ore to obtain a rare earth leaching solution; The rare earth leaching solution is subjected to centrifugal extraction using an organic extractant to obtain a rare earth-loaded organic phase and an aluminum-containing raffinate; The aluminum-containing raffinate is prepared to obtain a first leaching agent solution and a second leaching agent solution, and the ionic rare earth ore is leached; The hydrogen ion concentration in the first leaching agent solution is 0.00001 mol / L to 0.001 mol / L, the hydrogen ion concentration in the second leaching agent solution is 0.001 mol / L to 0.02 mol / L, and the aluminum content in the rare earth leachate is 20 mg / L to 3000 mg / L.
2. The method for reducing leaching of impurity aluminum in ionic rare earth ores according to claim 1, characterized in that: In the first leaching agent solution, the hydrogen ion concentration is 0.0001 mol / L to 0.001 mol / L; In the second leaching agent solution, the hydrogen ion concentration is 0.002 mol / L to 0.01 mol / L.
3. The method for reducing the leaching of impurity aluminum in ionic rare earth ores according to claims 1 and 2, characterized in that: In the first leaching agent solution, the concentration of cations other than hydrogen ions and aluminum ions is 0.15 mol / L to 0.4 mol / L; In the second leachate solution, the concentration of cations other than hydrogen ions and aluminum ions is 0.05 mol / L to 0.15 mol / L.
4. The method for reducing the leaching of impurity aluminum in ionic rare earth ores according to claim 1, characterized in that: The first leaching agent solution and the second leaching agent solution respectively include at least one of magnesium sulfate, magnesium chloride, calcium chloride, sodium sulfate, sodium chloride, potassium chloride, potassium sulfate and ferrous sulfate.
5. The method for reducing leaching of impurity aluminum in ionic rare earth ores according to claim 4, characterized in that: The first lixiviant solution and the second lixiviant solution respectively include at least one of magnesium sulfate, magnesium chloride and calcium chloride.
6. The method for reducing leaching of impurity aluminum in ionic rare earth ores according to claim 5, characterized in that: In the first leachant solution and the second leachant solution, except for hydrogen ions and aluminum ions, the molar percentages of various cations are: magnesium ions 40% to 99%, calcium ions 1% to 55%, sodium ions, potassium ions and / or ferrous ions 0% to 50%.
7. The method for reducing leaching of impurity aluminum in ionic rare earth ores according to claim 6, characterized in that: The organic extractant is an acidic phosphorus extractant; The concentration of the acidic phosphorus extractant is 0.5 mol / L to 1.5 mol / L.
8. The method for reducing leaching of impurity aluminum in ionic rare earth ores according to claim 7, characterized in that: The organic extractant includes at least one of P507, P204, P227, and Cyanex272.
9. The method for reducing leaching of impurity aluminum in ionic rare earth ores according to claim 8, characterized in that: The contact time between the organic extractant and the rare earth leaching solution is 5s to 60s.
10. The method for reducing leaching of impurity aluminum in ionic rare earth ores according to claim 9, characterized in that: The aluminum content in the aluminum-containing raffinate is 20 mg / L to 3000 mg / L.