Method for reducing leaching of impurity aluminum in ionic rare earth ore

Abstract

The invention discloses a method for reducing leaching of impurity aluminum in ionic rare earth ore, which comprises the following steps: leaching the ionic rare earth ore by adopting a first leaching agent solution and a second leaching agent solution in sequence to obtain a rare earth leaching solution; carrying out centrifugal extraction on the rare earth leachate by adopting an organic extraction agent to obtain a rare earth loaded organic phase and aluminum-containing raffinate; and 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. By adopting the mode of sectional leaching of the leaching agent solution and blending and circulating ore leaching of the aluminum-containing raffinate, form transformation of hydroxyl adsorption state aluminum and exchange desorption of ion exchange state aluminum are inhibited from the source, and the leaching amount of impurity aluminum is reduced by 90% or above compared with that of a conventional inorganic salt leaching-precipitation enrichment process.

Description

Technical Field

[0001] The 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

[0002] Rare earth elements, especially medium and heavy rare earth elements, are known as "vitamins of modern industry" and "treasure trove of new materials", and are indispensable core basic materials for the preparation of high-end magnetic materials, laser crystals, etc. Ionic rare earth ores are mainly distributed in seven southern provinces of my country, including Jiangxi, Guangdong, Guangxi Zhuang Autonomous Region, Hunan, Fujian, Yunnan, and Zhejiang. Medium and heavy rare earth elements account for as much as 40% to 90%, and are precious medium and heavy rare earth strategic resources in my country.

[0003] The rare earths in ionic rare earth ores are mainly adsorbed on clay minerals such as kaolinite in the form of hydrated ions, and the rare earth grade is extremely low (only 0.03% to 0.1% REO). my country has pioneered a unique process for ammonium sulfate leaching-ammonium bicarbonate precipitation enrichment to produce rare earth concentrates, realizing 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. The production of 1 ton of ionic rare earth concentrate (REO) consumes more than 10 tons of ammonium salt, which is 3 to 4 times excessive, and produces a large amount of ammonia nitrogen wastewater and radioactive waste residue. In addition, rare earth leaching liquid uses ammonium bicarbonate for neutralization and impurity removal, precipitation and enrichment of rare earths. About 97% of the impurity aluminum is hydrolyzed into the impurity removal slag, and the remaining about 3% of the impurity aluminum enters the rare earth carbonate product. The precipitation mother liquor basically does not contain 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 aluminum-free precipitation mother liquor is returned to the mine for leaching, the impure aluminum is continuously leached, and the leaching amount of impure aluminum is greatly increased.

[0004] According to the Groundwater Quality Standard (GB / T 14848-2017), 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 (GB 3838-2002), 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 aluminum concentration 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 reasons are: (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 growth of plant roots 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 - Combined to form [AlF6] 3- 、Al(OH)4- Especially when pH <5.5, F in water - Almost all of them generate [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 mine environment.

[0005] In order to solve the above problems, the prior art proposes that in the process of leaching ionic rare earth ores with ammonium salt or magnesium salt solutions, an inhibitor such as hexamethylenetetramine, hexamethylenetetramine, formates, acetates, tartaric acid, and a composite cationic surfactant (containing hexadecyltrimethylammonium bromide and dodecyltrimethylammonium bromide) is introduced, and the impurity aluminum in the ionic rare earth ores is retained in the ionic rare earth ore body by chemical reactions such as complexation between the inhibitor and the impurity aluminum, thereby achieving the purpose of reducing the leaching of impurity aluminum; in addition, a method of leaching by adding a leaching aid containing carboxymethyl chitosan, modified starch, polyhydroxy alcohol and potassium acetate to an ammonium salt solution, and a method of segmented leaching using an acetic acid solution (pH=3-4), a magnesium salt or a calcium salt solution are also proposed, which can also reduce the leaching of impurity aluminum in the ionic rare earth ores to a certain extent.

[0006] 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 in 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. Summary of the invention

[0007] The purpose of the embodiment 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-centrifugal extraction and enrichment of leaching agent solution, the form transformation of hydroxyl adsorbed aluminum and the exchange and desorption of ion exchanged aluminum are suppressed from the source. Under the premise of not affecting the rare earth leaching rate, the leaching amount of impurity aluminum is greatly reduced, and the leaching agent consumption and production cost are reduced.

[0008] In order 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:

[0009] 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;

[0010] 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;

[0011] 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;

[0012] 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.

[0013] Further, in the first leaching agent solution, the hydrogen ion concentration is 0.0001 mol / L to 0.001 mol / L;

[0014] In the second leaching agent solution, the hydrogen ion concentration is 0.002 mol / L to 0.01 mol / L.

[0015] 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;

[0016] 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.

[0017] 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.

[0018] 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.

[0019] 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%.

[0020] Further, the organic extractant is an acidic phosphorus extractant;

[0021] The concentration of the acidic phosphorus extractant is 0.5 mol / L to 1.5 mol / L.

[0022] Furthermore, the organic extractant includes at least one of P507, P204, P227, and Cyanex272.

[0023] Furthermore, the contact time between the organic extractant and the rare earth leaching solution is 5s to 60s.

[0024] Furthermore, the aluminum content in the aluminum-containing raffinate is 20 mg / L to 3000 mg / L.

[0025] The above technical solution of the embodiment of the present invention has the following beneficial technical effects:

[0026] 1. By adding leaching agent solutions 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, and the pH of the leaching solution is controlled at a higher level to avoid the conversion of hydroxyl-adsorbed aluminum in the ionic rare earth ore into ion-exchange or water-soluble aluminum; then the second leaching agent solution (lower concentration leaching agent) is used to reduce the consumption of leaching agent, and the pH of the leaching solution is controlled at a lower level to avoid the reverse adsorption of the rare earth ions exchanged and desorbed in the ionic rare earth ore.

[0027] 2. Through the leaching method of circulating leaching with aluminum-containing raffinate, due to the existence of a certain solid-liquid distribution ratio of impure aluminum between 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 avoiding the exchange and desorption of ion-exchange aluminum in the ionic rare earth ore into water-soluble aluminum.

[0028] 3. Through the above-mentioned segmented leaching of the leaching agent solution and the circulating leaching of the aluminum-containing raffinate, efficient and rapid leaching of rare earths can be 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 consumption of leaching agents is greatly reduced, and the production cost is significantly reduced.

[0029] 4. The use of leaching agent solution segmented leaching-centrifugal extraction enrichment can avoid the radioactive waste residue and ammonia nitrogen wastewater pollution in the conventional inorganic salt leaching-precipitation enrichment process from the source, greatly reducing the environmental pressure of ionic rare earth mining enterprises. In addition, the leaching agent solution segmented leaching-centrifugal extraction enrichment technology can be used to treat all minerals containing ionic rare earths, and has a wide range of applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a schematic diagram of specific steps of the method for reducing the leaching of impurity aluminum in ionic rare earth ores provided by an embodiment of the present invention;

[0031] Figure 2 It is a schematic diagram of the process flow of a method for reducing leaching of impurity aluminum in ionic rare earth ores provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is 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 only exemplary and are not intended to limit the scope of the present invention. In addition, in the following description, the description of well-known structures and technologies is omitted to avoid unnecessary confusion of the concept of the present invention.

[0033] Please refer to Figure 1 and Figure 2 The embodiment of the present invention provides a method for reducing the leaching of impurity aluminum in ionic rare earth ores, comprising the following steps:

[0034] 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 leaching solution.

[0035] The invention adopts a treatment method of adding leaching agent solutions successively, firstly adopts a first leaching agent solution (0.15 mol / L to 0.4 mol / L) 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, and at the same time controls a relatively high pH value of the leaching solution (hydrogen ion concentration is 0.00001 mol / L to 0.001 mol / L) to avoid the conversion of hydroxyl-adsorbed aluminum in the ionic rare earth ore into ion-exchange or water-soluble aluminum; then adopts a second leaching agent solution (0.05 mol / L to 0.15 mol / L) to reduce the leaching agent consumption, and at the same time controls a relatively low pH value of the leaching solution (hydrogen ion concentration is 0.001 mol / L to 0.02 mol / L) to avoid the reverse adsorption of the exchanged and desorbed rare earth ions in the ionic rare earth ore; and by means of segmented leaching with the above-mentioned leaching agent solution, efficient and rapid leaching of rare earth is achieved, and at the same time, a large amount of impurity aluminum leaching caused by the morphological transformation of hydroxyl-adsorbed aluminum is avoided.

[0036] Step S2, using an organic extractant to centrifuge the rare earth leaching solution to obtain a rare earth-loaded organic phase and an aluminum-containing raffinate.

[0037] The rare earth leaching solution contains rare earth ions, aluminum ions, leaching agent cations (such as Mg 2+ , Ca 2+ 、Na + , K + , Fe 2+ The content of aluminum is 20-3000 mg / L (calculated as aluminum oxide). The 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.

[0038] Step S3, preparing the aluminum-containing raffinate to obtain a first leaching agent solution and a second leaching agent solution, and leaching the ionic rare earth ore.

[0039] In the leaching process of ionic rare earth ores, due to the ion exchange between the ion exchange agent cations and the rare earths in the ionic rare earth ores, the concentration of the ion exchange agent cations in the rare earth leachate is usually lower than that in the leachate solution. In the centrifugal extraction and enrichment process of the rare earth leachate, the ion exchange agent cations are basically not extracted and retained in the aluminum-containing raffinate, but the pH value of the raffinate will become lower. Therefore, when the aluminum-containing raffinate is circulated back to the mine for leaching, the concentration of the ion exchange agent cations, pH, etc. of the aluminum-containing raffinate need to be adjusted to the range required by the first leaching agent solution and the second leaching agent solution to ensure that the rare earths in the ionic rare earth ores are fully exchanged and desorbed.

[0040] 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.

[0041] Since there is a certain solid-liquid distribution ratio between impurity aluminum in clay minerals such as kaolinite and 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, the aluminum-containing raffinate is circulated back to the mine for leaching, and a small amount of aluminum ions in the raffinate can also act as a leaching agent, further reducing the consumption of leaching agents.

[0042] Among them, the hydrogen ion concentration in the first lixiviant solution is 0.00001mol / L~0.001mol / L, in the second lixiviant solution, the hydrogen ion concentration is 0.001mol / L~0.02mol / L, and the aluminum content in the rare earth leaching solution is 20mg / L~3000mg / L.

[0043] Furthermore, in the first leaching agent solution, the hydrogen ion concentration is preferably 0.0001 mol / L to 0.001 mol / L; in the second leaching agent solution, the hydrogen ion concentration is preferably 0.002 mol / L to 0.01 mol / L.

[0044] 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.

[0045] 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.

[0046] Preferably, the first leaching agent solution and the second leaching agent solution respectively include at least one of magnesium sulfate, magnesium chloride and calcium chloride.

[0047] The treatment method of segmented leaching of magnesium salt leaching agent solution and circulating leaching of aluminum-containing raffinate solution adopted in the present invention greatly reduces the consumption of leaching agent and significantly reduces the production cost. The segmented leaching-centrifugal extraction and enrichment of magnesium salt leaching agent solution can avoid the radioactive waste residue and ammonia nitrogen wastewater pollution in the conventional inorganic salt leaching-precipitation enrichment process from the source, greatly reducing the environmental protection pressure of ionic rare earth mining enterprises.

[0048] According to the demand of ionic rare earth mine soil for nutrients such as magnesium and calcium, the proportions of magnesium, calcium, etc. in the first leaching agent solution and the second leaching agent solution are appropriately adjusted so that the tailings after leaching meet the soil nutrient requirements.

[0049] 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%.

[0050] 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. The use of acidic phosphorus extractants widely used in the rare earth industry allows the centrifugal extraction process to be carried out under acidic conditions, effectively avoiding problems such as emulsification / three-phase problems caused by hydrolysis of impurities such as aluminum in the conventional saponification extraction process.

[0051] Optionally, the organic extractant is preferably at least one of P507, P204, P227, and Cyanex272.

[0052] Specifically, the contact time between the organic extractant and the rare earth leaching solution in the above step S2 is 5s to 60s. Centrifugal extraction is performed under acidic conditions using an acidic phosphorus extractant, and the contact time between the organic extractant and the rare earth leaching solution is controlled to be 5s to 60s. The difference in extraction kinetics between rare earth and aluminum is utilized, and while rare earth is extracted efficiently, impurity aluminum is hardly extracted and retained in the raffinate.

[0053] Specifically, the aluminum content in the aluminum-containing raffinate in the above step S2 is 20 mg / L to 3000 mg / L.

[0054] The present invention adopts the method of staged leaching of leaching agent solution and circulating leaching of ore by mixing aluminum-containing raffinate, thereby inhibiting the form transformation of hydroxyl adsorbed aluminum and the exchange desorption of ion exchanged aluminum from the source, and the leaching amount of impurity aluminum is reduced by more than 90% compared with the conventional inorganic salt leaching-precipitation enrichment process.

[0055] The technical solution of the present invention is further illustrated below through several comparative examples and several embodiments.

[0056] Example 1

[0057] The ion-exchange rare earth grade of the ionic rare earth ore is 0.05%, and the ion-exchange aluminum grade is 0.035%. The first leaching agent solution and the second leaching agent solution are used to leach the ionic rare earth ore in turn. Among them, the hydrogen ion concentration of the first leaching agent solution is 0.00001 mol / L, the cation concentration other than hydrogen ions is 0.20 mol / L, and the main component of the leaching agent is MgSO4; the hydrogen ion concentration of the second leaching agent solution is 0.01 mol / L, the cation concentration other than hydrogen ions and aluminum ions is 0.10 mol / L, and the main components of the leaching agent are MgSO4 and CaCl2, wherein the molar percentages of magnesium ions and calcium ions are 99% and 1% respectively. The rare earth leachate obtained after the above-mentioned leaching agent treatment is centrifuged using an organic extractant to obtain a rare earth-loaded organic phase and an aluminum-containing raffinate. The organic extractant is P507, the concentration of P507 is 1.0 mol / L, the volume flow ratio of P507 to rare earth leaching solution is 1:20, and the contact time is 15 seconds. The obtained aluminum-containing raffinate is prepared and recycled for leaching.

[0058] 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%.

[0059] In addition, Comparative Examples 1 to 6 and Examples 2 to 41 are shown in Table 1a, Table 1b and Table 1c.

[0060] Table 1a

[0061]

[0062]

[0063]

[0064]

[0065] Table 1b

[0066]

[0067]

[0068]

[0069] Table 1c

[0070]

[0071]

[0072]

[0073] The embodiment of the present invention aims to protect a method for reducing the leaching of impurity aluminum in ionic rare earth ore, comprising the following steps: 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 leachate; using an organic extractant to centrifuge the rare earth leachate 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 0.00001mol / L to 0.001mol / L, and the hydrogen ion concentration in the second leaching agent solution is 0.001mol / L to 0.02mol / L, and the aluminum content in the rare earth leachate is 20mg / L to 3000mg / L. The above technical solution has the following effects:

[0074] 1. By adding leaching agent solutions 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, and the pH of the leaching solution is controlled at a higher level to avoid the conversion of hydroxyl-adsorbed aluminum in the ionic rare earth ore into ion-exchange or water-soluble aluminum; then the second leaching agent solution (lower concentration leaching agent) is used to reduce the consumption of leaching agent, and the pH of the leaching solution is controlled at a lower level to avoid the reverse adsorption of the rare earth ions exchanged and desorbed in the ionic rare earth ore.

[0075] 2. Through the leaching method of circulating leaching with aluminum-containing raffinate, due to the existence of a certain solid-liquid distribution ratio of impure aluminum between 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 avoiding the exchange and desorption of ion-exchange aluminum in the ionic rare earth ore into water-soluble aluminum.

[0076] 3. Through the above-mentioned segmented leaching of the leaching agent solution and the circulating leaching of the aluminum-containing raffinate, efficient and rapid leaching of rare earths can be 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 consumption of leaching agents is greatly reduced, and the production cost is significantly reduced.

[0077] 4. The use of leaching agent solution segmented leaching-centrifugal extraction enrichment can avoid the radioactive waste residue and ammonia nitrogen wastewater pollution in the conventional inorganic salt leaching-precipitation enrichment process from the source, greatly reducing the environmental pressure of ionic rare earth mining enterprises. In addition, the leaching agent solution segmented leaching-centrifugal extraction enrichment technology can be used to treat all minerals containing ionic rare earths, and has a wide range of applications.

[0078] It should be understood that the above specific embodiments of the present invention are only used to illustrate or explain the principles of the present invention, and do not constitute a limitation 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 in the protection scope of the present invention. In addition, the appended claims of the present invention are intended to cover all changes and modifications that fall within the scope and boundaries of the appended claims, or the equivalent forms of such scope and boundaries.

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.

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