A method for removing impurities from rare earth liquid
By using a mixture of P507, isooctanol and kerosene as the extraction agent, combined with saponification extraction and hydrochloric acid back-extraction steps, the problem of difficulty in removing ytterbium and gluten in the existing process has been successfully solved, and the production of high-purity rare earth material liquid is achieved, and the production cost is reduced.
Patent Information
- Application Number
- CN202411953941.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-27
- Publication Date
- 2025-04-01
AI Technical Summary
The existing rare earth separation process is difficult to completely remove bblt and lutetium elements, affecting the purity of dysprosium oxide, and it is difficult to effectively reduce the content of light rare earth impurities.
A mixture of P507, isooctanol and kerosene is used as the extraction agent to exchange and extract with rare earth liquids with excess content of ytterbium and leutrogen. Combined with saponification extraction and hydrochloric acid back-extraction steps, a single rare earth liquid is separated and recovered.
It has achieved effective removal of ytterbium and gluten, reached the quality standard of 4N dysprosium oxide products, and reduced the content of light rare earth impurities, improved the purity of rare earth liquid, and smooth process and convenient operation, reducing production costs.
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Figure CN119736493A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of hydrometallurgy, and in particular relates to a method for removing impurities from rare earth liquid. Background Art
[0002] Rare earths have excellent optical, electrical, magnetic, superconducting, catalytic and other physical properties. They are mainly used in the fields of petroleum, chemical industry, metallurgy, textile, ceramic glass, permanent magnetic materials, etc. They are known as "industrial MSG", "industrial vitamins" and "the mother of new materials" and are precious strategic metal resources. Rare earth elements have similar electronic layer structures and the "lanthanide contraction" phenomenon of rare earths, which results in similar ionic radii between rare earth elements, and determines the similarity of the physical and chemical properties of rare earth elements, making it difficult to separate rare earth elements. Especially for heavy rare earth elements such as ytterbium (Yb) and lutetium (Lu), the presence of these impurities not only affects the purity of rare earth products, but also limits the further application of rare earth elements. Therefore, developing an efficient and economical method for removing impurities from rare earth liquid is of great significance to improving the quality and market competitiveness of rare earth products.
[0003] At present, most high-purity, single rare earth elements are separated and prepared by solvent extraction. In the process of separating rare earth elements by solvent extraction, thousands of extraction tanks are generally used to separate rare earth elements through fuzzy extraction process. In the current rare earth separation production process, due to the problem of the number of stages of the extraction tank for 2N-3N purity dysprosium oxide in the early design, it is difficult to completely separate ytterbium and lutetium elements (Yb / Lu≤0.001%), resulting in high ytterbium and lutetium in the stripped dysprosium solution in the dysprosium separation extraction tank (Yb / Lu=0.01-0.2%), which greatly affects the purity of dysprosium oxide. Summary of the invention
[0004] In view of the shortcomings of the prior art, the present invention aims to provide a method for removing impurities from a rare earth liquid, which can reduce the content of ytterbium and lutetium in the product, meet the quality standard requirements of 4N dysprosium oxide products, and reduce the content of light rare earth impurities in the liquid.
[0005] The technical solution of the present invention is as follows:
[0006] A method for removing impurities from a rare earth liquid comprises the following steps:
[0007] (1) adding an extractant to a rare earth feed liquid with excessive ytterbium and lutetium content and stirring and mixing to obtain a raffinate A and a loaded organic phase A; the extractant is a mixture of P507, isooctyl alcohol and kerosene;
[0008] (2) adding a saponification extractant to the raffinate A and stirring and mixing to obtain a raffinate B and a loaded organic phase B;
[0009] (3) adding dilute hydrochloric acid to the loaded organic phase B for washing to obtain an aqueous phase and a washed loaded organic phase, wherein the aqueous phase is recovered and the washed loaded organic phase is stripped with hydrochloric acid to separate the phases to obtain a single rare earth feed solution.
[0010] Furthermore, in step (1), the rare earth liquid with excessive ytterbium and lutetium content contains one or more rare earth elements selected from the group consisting of gadolinium, terbium, dysprosium, holmium, erbium and yttrium.
[0011] Furthermore, in step (1), the rare earth solution with excessive ytterbium and lutetium content has a rare earth content of 1 to 2 mol / L and an acidity of 0.1 to 0.2 mol / L.
[0012] Furthermore, in step (1), the volume ratio of P507, isooctyl alcohol and kerosene in the extractant is (40-50):(15-20):(30-45).
[0013] Furthermore, in step (1), the volume ratio of the extractant to the rare earth solution with excessive ytterbium and lutetium content is (2-5):1.
[0014] Furthermore, in step (1), the stirring and mixing is performed at room temperature or at 25-45°C.
[0015] Furthermore, in step (2), the saponification extractant is a mixture of P507, isooctyl alcohol and kerosene, the saponifier is one of liquid alkali, ammonia water and sodium carbonate, and the saponification rate of the saponification extractant is 30-36%.
[0016] Furthermore, in step (3), the concentration of the dilute hydrochloric acid is 0.1 to 0.2 mol / L, and the washing amount is 1 to 5% of the total mass of the rare earth elements.
[0017] The process of the present invention is as follows Figure 1 shown.
[0018] Due to the adoption of the above technical solution, the beneficial effects of the present invention are:
[0019] 1. The present invention adopts a mixture of P507, isooctyl alcohol and kerosene as an extractant, and exchanges ytterbium and lutetium ions in the feed liquid with hydrogen ions at a certain acidity, exchanges ytterbium and lutetium ions in the aqueous phase into the organic phase for separation from dysprosium, and the loaded organic phase is recycled after hydrochloric acid stripping, without introducing other rare earth impurities and non-rare earth impurities, and the impurity removal cost is low;
[0020] 2. The present invention realizes the removal of ytterbium and lutetium from rare earth liquid, and can reduce the content of light rare earth impurities such as lanthanum and cerium, further improving the purity of rare earth liquid;
[0021] 3. The impurity removal process of the present invention can be carried out in a reaction kettle, which can be connected with the existing extraction-precipitation process. The process is smooth and easy to operate, which reduces the production cost. BRIEF DESCRIPTION OF THE DRAWINGS
[0022] Figure 1 It is a process flow chart of the present invention. DETAILED DESCRIPTION
[0023] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.
[0024] Example 1
[0025] This embodiment provides a method for removing impurities from a rare earth liquid, comprising the following steps:
[0026] The rare earth feed solution in this embodiment is a dysprosium chloride rare earth feed solution. The concentration of the rare earth feed solution is measured to be 1.452 mol / L, the acidity of the feed solution is 0.13 mol / L, and the content of light rare earth elements and rare earth impurities is shown in Table 1, wherein the contents of lanthanum, cerium, ytterbium and lutetium are greater than 0.01%, exceeding the limit value of the product quality standard; the extractant is a mixture of P507, isooctyl alcohol and kerosene, wherein the volume ratio of P507, isooctyl alcohol and kerosene is 45:15:40.
[0027] (1) 100 mL of dysprosium chloride solution was mixed with 300 mL of extractant, the mixture was kept at 35° C. and stirred for 45 minutes, and after standing for phase separation, the organic phase was discharged, and the aqueous phase was repeatedly extracted to obtain a rare earth solution with ytterbium and lutetium removed;
[0028] (2) Take 800 mL of extractant, add liquid alkali to the extractant according to 3 times the amount of dysprosium (in mol) in the rare earth solution, and continue to stir with the rare earth solution except ytterbium and lutetium in step (1) for 20 minutes. After standing and phase separation, discharge the aqueous phase, add 50 ml of 0.15 mol / L hydrochloric acid to the organic phase and stir for 30 minutes. After stirring, age and stand for 10 minutes, discharge the aqueous phase, add 80 ml of 5 mol / L hydrochloric acid to the organic phase and stir for 20 minutes; age and stand, after phase separation, the aqueous phase obtained is a qualified single pure dysprosium solution. The rare earth concentration, acidity and rare earth impurity element content of the dysprosium solution are analyzed as shown in Table 1.
[0029] Table 1
[0030]
[0031] Example 2
[0032] This embodiment provides a method for removing impurities from a rare earth liquid, comprising the following steps:
[0033] The rare earth feed solution in this embodiment is a dysprosium chloride rare earth feed solution. The concentration of the rare earth feed solution is measured to be 1.335 mol / L, the acidity of the feed solution is 0.16 mol / L, and the content of light rare earth elements and rare earth impurities is shown in Table 2, wherein the contents of lanthanum, cerium, ytterbium and lutetium are greater than 0.01%, exceeding the limit value of the product quality standard; the extractant is a mixture of P507, isooctyl alcohol and kerosene, wherein the volume ratio of P507, isooctyl alcohol and kerosene is 40:18:45.
[0034] (1) 100 mL of dysprosium chloride solution was mixed with 200 mL of extractant, the mixture was kept at 25° C. and stirred for 45 minutes, and after standing for phase separation, the organic phase was discharged, and the aqueous phase was repeatedly extracted to obtain a rare earth solution with ytterbium and lutetium removed;
[0035] (2) Take 800 mL of extractant, add liquid alkali to the extractant according to 3 times the amount of dysprosium (in mol) in the rare earth solution, and continue to stir with the rare earth solution except ytterbium and lutetium in step (1) for 20 minutes. After standing and phase separation, discharge the aqueous phase, add 0.10 mol / L hydrochloric acid 50 ml to the organic phase and stir for 30 minutes. After stirring, age and stand for 10 minutes, discharge the aqueous phase, add 5 mol / L hydrochloric acid 80 ml to the organic phase and stir for 20 minutes; age and stand, after phase separation, the aqueous phase obtained is a qualified single pure dysprosium solution. The rare earth concentration, acidity and rare earth impurity element content of the dysprosium solution are analyzed as shown in Table 2.
[0036] Table 2
[0037]
[0038] Example 3
[0039] This embodiment provides a method for removing impurities from a rare earth liquid, comprising the following steps:
[0040] The rare earth feed solution in this embodiment is a dysprosium chloride rare earth feed solution. The concentration of the rare earth feed solution is measured to be 1.329 mol / L, the acidity of the feed solution is 0.18 mol / L, and the content of light rare earth elements and rare earth impurities is shown in Table 3, wherein the contents of lanthanum, cerium, ytterbium and lutetium are greater than 0.01%, exceeding the limit value of the product quality standard; the extractant is a mixture of P507, isooctyl alcohol and kerosene, wherein the volume ratio of P507, isooctyl alcohol and kerosene is 50:20:30.
[0041] (1) 100 mL of dysprosium chloride solution was mixed with 500 mL of extractant, the mixture was kept at 45° C. and stirred for 45 minutes, and after standing for phase separation, the organic phase was discharged, and the aqueous phase was repeatedly extracted to obtain a rare earth solution with ytterbium and lutetium removed;
[0042] (2) Take 800 mL of extractant, add liquid alkali to the extractant according to 3 times the amount of dysprosium (in mol) in the rare earth solution, and continue to stir with the rare earth solution except ytterbium and lutetium in step (1) for 20 min. After standing and phase separation, discharge the aqueous phase, add 50 ml of 0.20 mol / L hydrochloric acid to the organic phase and stir for 30 min. After stirring, age and stand for 10 min, discharge the aqueous phase, add 80 ml of 5 mol / L hydrochloric acid to the organic phase and stir for 30 min. After aging and standing, after phase separation, the aqueous phase obtained is a qualified single pure dysprosium solution. The rare earth concentration, acidity and rare earth impurity element content of the dysprosium solution are analyzed as shown in Table 3.
[0043] Table 3
[0044]
[0045] The above description is a detailed description of the preferred feasible embodiments of the present invention, but the embodiments are not intended to limit the scope of the patent application of the present invention. All equivalent changes or modified changes completed under the technical spirit suggested by the present invention should fall within the patent scope covered by the present invention.
Claims
1. A method for removing impurities from a rare earth liquid, characterized in that: The steps include: (1) adding an extractant to a rare earth feed liquid with excessive ytterbium and lutetium content and stirring and mixing to obtain a raffinate A and a loaded organic phase A; the extractant is a mixture of P507, isooctyl alcohol and kerosene; (2) adding a saponification extractant to the raffinate A and stirring and mixing to obtain a raffinate B and a loaded organic phase B; (3) adding dilute hydrochloric acid to the loaded organic phase B for washing to obtain an aqueous phase and a washed loaded organic phase, wherein the aqueous phase is recovered and the washed loaded organic phase is stripped with hydrochloric acid to separate the phases to obtain a single rare earth feed solution.
2. The method for removing impurities from a rare earth liquid as claimed in claim 1, characterized in that: In step (1), the rare earth liquid with excessive ytterbium and lutetium content contains one or more rare earth elements selected from the group consisting of gadolinium, terbium, dysprosium, holmium, erbium and yttrium.
3. The method for removing impurities from a rare earth liquid as claimed in claim 1, characterized in that: In step (1), the rare earth solution with excessive ytterbium and lutetium content has a rare earth content of 1 to 2 mol / L and an acidity of 0.1 to 0.2 mol / L.
4. The method for removing impurities from a rare earth liquid as claimed in claim 1, characterized in that: In step (1), the volume ratio of P507, isooctyl alcohol and kerosene in the extractant is (40-50):(15-20):(30-45).
5. The method for removing impurities from a rare earth liquid as claimed in claim 1, characterized in that: In step (1), the volume ratio of the extractant to the rare earth solution with excessive ytterbium and lutetium content is (2-5):
1.
6. The method for removing impurities from a rare earth liquid as claimed in claim 1, characterized in that: In step (1), the stirring and mixing is carried out at room temperature or 25-45°C.
7. The method for removing impurities from a rare earth liquid as claimed in claim 1, characterized in that: In step (2), the saponification extractant is a mixture of P507, isooctyl alcohol and kerosene, the saponifier is one of liquid alkali, ammonia water and sodium carbonate, and the saponification rate of the saponification extractant is 30-36%.
8. The method for removing impurities from a rare earth liquid as claimed in claim 1, characterized in that: In step (3), the concentration of the dilute hydrochloric acid is 0.1-0.2 mol / L, and the washing amount is 1-5% of the total mass of the rare earth elements.