阅读说明：本技术 一种离子液体法稀土钆精制除铝的方法 (Method for removing aluminum by refining rare earth gadolinium with ionic liquid method ) 是由 张香平 李福建 董海峰 高红帅 白银鸽 张锁江 于 2020-05-18 设计创作，主要内容包括：本发明涉及一种离子液体法稀土钆溶液精制除铝制备高纯钆的方法,属于萃取分离领域。其特征在于使用具有特定结构的功能化离子液体为萃取剂,有机溶剂为稀释剂,组成具有选择性萃取铝的有机相,通过串级萃取实现稀土钆溶液高效除铝。除铝后的GdCl<Sub>3</Sub>溶液中杂质铝含量小于10ppm,稀土收率大于99.5％,满足高纯钆(>4N5)的杂质含量要求。本发明与现有稀土溶液除铝方法比较,具有无需皂化、工艺简单、成本低、除铝效率高、稀土损失少的优点。(The invention relates to a method for preparing high-purity gadolinium by refining and removing aluminum from a rare earth gadolinium solution by an ionic liquid method, and belongs to the field of extraction and separation. The method is characterized in that a functionalized ionic liquid with a specific structure is used as an extractant, an organic solvent is used as a diluent to form an organic phase with selective aluminum extraction, and the rare earth gadolinium solution is subjected to high-efficiency aluminum removal through cascade extraction. GdCl after removing aluminum 3 The content of impurity aluminum in the solution is less than 10ppm, the yield of rare earth is more than 99.5 percent, and the high-purity gadolinium (gadolinium)>4N5) is required. Compared with the existing aluminum removal method by using rare earth solution, the method has the advantages of no need of saponification, simple process, low cost, high aluminum removal efficiency and less rare earth loss.)

1. The method is characterized in that the ionic liquid extractant does not need to be subjected to conventional saponification, and the volume ratio of the organic phase O, the rare earth solution F, the pickling acid W and the stripping agent S is 10-50: 100-500: 10-50: 10-100L/h, and the rare earth gadolinium in the method is GdCl containing 0.1-2.0 mol/L₃The method comprises the steps of preparing a solution, wherein the content of impurity aluminum is 10-10000 ppm, the washing acid is 0.1-2.0 mol/L dilute hydrochloric acid, the back extraction agent is 1.0-5.0 mol/L hydrochloric acid, the ionic liquid regeneration alkali is an alkali solution prepared from water and concentrated alkali or concentrated ammonia water according to the volume ratio of 1-50: 50-1000, the number of stages is determined according to the extraction stage (1-a stage), the washing stage ((a +1) stage-b stage), the back extraction stage ((b +1) stage-c stage) is 10: 6: 4, after the back extraction of the extractant acid, the ionic liquid is regenerated by alkali, the required number of stages ((c +1) stage-d stage) is 2-6 stages, the mixing time is 5-10 min, the volume ratio of a mixing chamber and a clarifying chamber of an extraction tank is 1: 3-5, and the aluminum-removed GdCl is prepared according to the method₃The content of impurity aluminum in the solution is less than 10ppm, and the yield of rare earth is more than 99.5%.

2. The method for removing aluminum by refining rare earth gadolinium by the ionic liquid method according to claim 1, wherein the method comprises the following steps: the ionic liquid has an anion and cation structure, anions are carboxylic acids, fatty acids and phosphate compounds, particularly anions are Naphthenic Acid (NA), sec-octylphenoxyacetic acid (CA12), sec-nonylphenoxypetic acid (CA100), oleic acid (oleate), linoleic acid (linoleate), linolenic acid (linolenate), di- (2-ethylhexyl) phosphate (P204) and acid ions provided by 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester (P507), cations are quaternary ammonium compounds and quaternary phosphorus compounds, and particularly cations are cations provided by trioctylmethylammonium chloride (N1888Cl), tetrabutylammonium chloride (N4444Cl), tetraoctylammonium chloride (N8888Cl), tetraheptylammonium chloride (N7777Cl) and trihexyltetradecylphosphonium chloride (P666,14 Cl).

3. The method for removing aluminum from rare earth gadolinium by refining with an ionic liquid method according to claim 1, wherein the extractant is prepared by compounding an ionic liquid and an organic solvent, the concentration of the extractant is 0.01-1.5 mol/L, and preferably, the concentration of the extractant in the organic phase is 0.1-0.8 mol/L.

4. The method for removing aluminum by refining rare earth gadolinium by the ionic liquid method according to claim 1, wherein the method comprises the following steps: the organic solvent is one or a mixture of kerosene and octanol.

5. The method for removing aluminum from rare earth gadolinium by refining with an ionic liquid method according to claim 2, wherein the volume ratio of the organic phase O, the rare earth solution F, the washing acid W and the stripping agent S is 10-50: 100-500: 10-50: 10-100L/h.

6. The method for removing aluminum by refining rare earth gadolinium with an ionic liquid method according to claim 2, wherein the rare earth gadolinium solution is GdCl containing 0.8-1.8 mol/L₃The solution contains dilute hydrochloric acid with the impurity aluminum content of 300-6000 ppm and the washing acid content of 0.1-2.0 mol/L and the back extractant is2.0-5.0 mol/L hydrochloric acid, and the ionic liquid regeneration alkali is an alkali solution prepared from water and concentrated alkali or concentrated ammonia water according to a volume ratio of 1-20: 50-100.

7. The method for removing aluminum by refining rare earth gadolinium by the ionic liquid method according to claim 2, characterized by comprising the following steps: and (3) after the extractant is subjected to acid back extraction, regenerating the ionic liquid by using alkali, wherein the required stage number (stage (c +1) -stage (d)) is 2-4.

8. The method for removing aluminum by refining rare earth gadolinium by the ionic liquid method according to claim 2, characterized by comprising the following steps: the mixing time is 5-8 min, and the volume ratio of the mixing chamber to the clarifying chamber of the extraction tank is 1: 3 to 4.

[ technical field ] A method for producing a semiconductor device

The invention relates to a method for preparing high-purity gadolinium by refining and removing aluminum from a rare earth gadolinium solution, in particular to a method for refining and removing aluminum from rare earth gadolinium by an ionic liquid method, and belongs to the field of extraction and separation.

[ background of the invention ]

The rare earth element gadolinium has many unpaired electronic structures, can form strong magnetic torque, and has wide application in the fields of nuclear magnetic imaging contrast agents, nuclear reaction masking agents, magnetic memories, capacitors, magnetic refrigeration and the like, and the application needs to utilize intrinsic and inherent electronic characteristics of gadolinium, so that the higher the purity of gadolinium is, the better the gadolinium is, and the purity is generally required to be more than 99.995%. In a typical rare earth extraction separation process of a P507-HCl system, aluminum ions and gadolinium have equivalent coordination capacity with an extractant P507, so that aluminum impurity in a gadolinium product often exceeds the standard, and the product performance of high-purity gadolinium is greatly influenced.

At present, the main methods for removing the impurity aluminum in the rare earth solution are aluminum removal by a neutralization method (rare earth, 2014,35(5):30-35), an extraction method (CN101979680A) and a precipitation method (CN 105624440A). The neutralization method removes impurity aluminum in rare earth by preferentially precipitating aluminum ions in aqueous solution by increasing the pH value, has simple process and low cost, but is not suitable for preparing high-purity gadolinium by removing aluminum because the pH values of aluminum hydroxide and rare earth hydroxide precipitates are close and aluminum ions with amphoteric property often form colloid in the aqueous solution, so that the aluminum hydroxide is difficult to filter and the rare earth loss is large. The extraction method separates aluminum and rare earth by utilizing the difference of extraction sequence and distribution coefficient of rare earth and aluminum ions in naphthenic acid extractant, and has the characteristics of continuous process, high rare earth yield and low cost. The precipitation method is to use the solubility difference of rare earth and aluminum oxalate to carry out multi-step operation of the working procedures of oxalic acid precipitation, oxidizing roasting, acid dissolution, oxalic acid precipitation and oxidizing roasting on the aluminum-containing rare earth solution, but the cost is high, the loss rate of rare earth is also high, and the aluminum impurities are difficult to reach the standard.

The ionic liquid has the advantages of difficult volatilization, designability, wide liquid range, good conductivity, high stability and the like, is widely applied to the fields of gas separation, extraction desulfurization, lithium-magnesium separation and the like, has industrial application in part of fields, can selectively dissolve rare earth ions or aluminum ions, and has great application potential in the field of refining and removing aluminum from rare earth products. Compared with the aluminum removal process by the naphthenic acid method, the novel process for refining and removing aluminum by the rare earth gadolinium by the ionic liquid method does not need saponification, does not introduce new impurities such as Fe, Si, Ca, Mg, Hg and the like, and has the advantages of short process flow and low impurity content of products. Compared with the oxalic acid multiple precipitation method, the new process for refining and removing aluminum from rare earth gadolinium by the ionic liquid method does not need multiple precipitation crystallization, ignition and redissolution processes, and has the advantages of simple process, high rare earth yield, high aluminum removal efficiency and low cost.

[ summary of the invention ]

Aiming at the defects in the prior art, the invention aims to provide the technical scheme for refining and removing aluminum from rare earth gadolinium by the ionic liquid method, which has high aluminum removal efficiency, less rare earth loss and low comprehensive cost.

The invention designs and synthesizes serial functionalized ionic liquids, and preferably compounds the ionic liquids as a rare earth aluminum extraction extractant, and realizes the high-efficiency separation of aluminum in rare earth feed liquid directly through cascade extraction without saponification. The invention determines the extraction grade, the extractant concentration, the extraction amount and the washing amount of the cascade extraction process, so that aluminum ions in the rare earth gadolinium solution enter the extractant to the maximum extent, the Al/Gd separation is realized, and the aim of purifying the rare earth gadolinium is achieved.

Specifically, the invention is realized by the following technical scheme:

a method for refining and removing aluminum from rare earth gadolinium by an ionic liquid method uses functional ionic liquid with a specific structure as an extracting agent and an organic solvent as a diluent to form an organic phase with selective aluminum extraction, and realizes efficient aluminum removal of rare earth gadolinium solution by cascade extraction.

The method is characterized in that the ionic liquid extractant does not need to be subjected to conventional saponification, the volume ratio of the organic phase O, the rare earth solution F, the washing acid W and the stripping agent S is 10-50: 100-500: 10-50: 10-100L/h, and the rare earth gadolinium solution in the method is GdCl containing 0.1-2.0 mol/L₃The content of impurity aluminum in the solution is 10-10000 ppm, and the washing acid is 0.1-2.0 mol/L diluted hydrochloric acid, 1.0-5.0 mol/L hydrochloric acid as a back extraction agent, 1-5.0 mol/L aqueous alkali as an ionic liquid regeneration alkali, 10: 6: 4 of an extraction section (1-a level) ((a +1) level-b level): back extraction section ((b +1) level-c level), and 10: 6: 4 of an extraction agent acid back extraction, 2-6 levels of the required level ((c +1) level-d level) by regenerating the ionic liquid with the alkali after the extraction agent acid back extraction, 5-10 min of mixing time, 1: 3-5 of volume ratio of a mixing chamber and a clarifying chamber of an extraction tank, and 1-5 of GdCl for removing aluminum according to the method₃The content of impurity aluminum in the solution is less than 10ppm, and the yield of rare earth is more than 99.5%.

The ionic liquid has an anion and cation structure, anions are carboxylic acids, fatty acids and phosphate compounds, particularly anions are Naphthenic Acid (NA), sec-octylphenoxyacetic acid (CA12), sec-nonylphenoxypetic acid (CA100), oleic acid (oleate), linoleic acid (linoleate), linolenic acid (linolenate), di- (2-ethylhexyl) phosphate (P204) and acid ions provided by 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester (P507), cations are quaternary ammonium compounds and quaternary phosphorus compounds, and particularly cations are cations provided by trioctylmethylammonium chloride (N188188 1888Cl), tetrabutylammonium chloride (N4444Cl), tetraoctylammonium chloride (N8888Cl), tetraheptylammonium chloride (N7777Cl) and trihexyltetradecylphosphonium chloride (P66614 Cl).

The extractant is formed by compounding ionic liquid and an organic solvent, the concentration of the extractant is 0.01-1.5 mol/L, and preferably, the concentration of the ionic liquid extractant in the organic phase is 0.1-0.8 mol/L.

The organic solvent is one or a mixture of kerosene and octanol.

Preferably, the volume ratio of the organic phase O, the rare earth solution F, the washing acid W and the stripping agent S is 10-50: 100-500: 10-50: 10-100L/h.

Preferably, the rare earth gadolinium solution is GdCl containing 0.8-1.8 mol/L₃The method comprises the steps of preparing a solution, wherein the content of aluminum impurities in the solution is 300-6000 ppm, the content of washing acid in the solution is 0.1-2.0 mol/L dilute hydrochloric acid, the content of stripping agent in the solution is 2.0-5.0 mol/L hydrochloric acid, and the alkali for ionic liquid regeneration is an alkali solution prepared from water and concentrated alkali or concentrated ammonia water in a volume ratio of 1-20: 50-100.

Preferably, after the extractant is subjected to acid back extraction, the ionic liquid is regenerated by alkali, and the required number of stages ((c +1) stage-d stage) is 2-4 stages.

Preferably, the mixing time is 5-8 min, and the volume ratio of the mixing chamber to the clarifying chamber of the extraction tank is 1: 3-4;

the ionic liquid extractant has the characteristics of large Al/Gd separation coefficient and high separation efficiency, and the maximum separation efficiency reaches 36.

Compared with the process for removing aluminum from naphthenic acid, the method does not need an alkali saponification process, can avoid the rare earth product pollution caused by impurities such as Fe, Si, Ca, Mg, Hg and the like brought by a saponifier in the process of removing aluminum from naphthenic acid, and simultaneously has the characteristics that the organic phase is not easy to emulsify due to the strong hydrophobicity of the ionic liquid in the process of removing aluminum (as shown in figure 1), and the obtained gadolinium solution has high purity and the process is easy to control.

The method has simple extraction and recovery of the ionic liquid, and in the regeneration process, the strong hydrophobicity of the ionic liquid ensures that the phase separation is good, so that the impurity ions in the liquid alkali and the ammonia water are continuously left in the aqueous solution to be discharged in the form of wastewater, and the rare earth gadolinium product is not polluted.

Compared with the method for removing aluminum by oxalic acid precipitation, the method has the advantages of simple process, low cost and less rare earth loss.

[ description of the drawings ]

FIG. 1 is a flow chart of a process for refining and removing aluminum from rare earth gadolinium by an ionic liquid method according to the present invention;

[ detailed description ] embodiments