A process for extracting and separating hafnium from zirconium oxychloride mother liquor

Abstract

The invention relates to a process for extracting and separating hafnium from zirconium oxychloride mother liquor, and belongs to the technical field of hydrometallurgy. The extractant used in the invention is a mixture of an organic acid extractant, dinonylnaphthalenesulfonic acid and a sulfonic acid surfactant; in the solvent extraction system of the invention, since hydrogen bonds can be formed between the organic acid extractant and the dinonylnaphthalenesulfonic acid, the volatility of the organic acid extractant can be reduced, the loss of the extractant during use is reduced, the solvent can be recovered, and the separation effect is good.

Description

Technical Field

[0001] The invention belongs to the technical field of hydrometallurgy and relates to a process for extracting and separating hafnium from zirconium oxychloride mother liquor. Background Art

[0002] In nature, hafnium and zirconium exist as associated minerals, and their extranuclear electron arrangements are similar. Affected by the "lanthanide contraction" effect, their physical and chemical properties are very similar, resulting in low separation efficiency and incomplete separation. At present, the solvent extraction method is mainly used to separate hafnium and zirconium. The advantages of the solvent extraction method are low cost, high output, simple equipment, complete separation, and continuous operation.

[0003] Nowadays, the solvent extraction methods used in actual production are mainly MIBK-NH4SCN method, TBP-HNO3-HCl method and TOA / N235-H2SO4 method. However, the current hafnium-zirconium separation methods are difficult to achieve continuous and effective large-scale separation of hafnium-zirconium.

[0004] The MIBK-NH4SCN system is a common method for preferentially extracting hafnium and is also the most widely used approach in actual production. Although this method achieves effective separation of zirconium and hafnium, the separation coefficient is not large enough, and the system is unstable, easy to decompose, and difficult to control. In addition, the HSCN complex in the industrial wastewater discharged by this method will produce hydrogen sulfide, hydrocyanic acid, and mercaptan, which are harmful to the environment. Summary of the invention

[0005] The object of the present invention is to provide a process for extracting and separating hafnium from zirconium oxychloride mother liquor. The process has good effect of extracting and separating zirconium and hafnium, the solvent can be recovered, and the obtained hafnium has high purity.

[0006] The purpose of the present invention can be achieved through the following technical solutions:

[0007] A process for extracting and separating hafnium from zirconium oxychloride mother liquor comprises the following steps:

[0008] S1. Prepare the acid solution of zirconium oxychloride:

[0009] Dissolve zirconium oxychloride in water, add nitric acid and hydrochloric acid to make the acidity of the mixed solution 5-8 mol / L and the concentration of zirconium ions 20-50 g / L;

[0010] S2. Preparation of extraction agent:

[0011] An organic acid extractant, dinonylnaphthalenesulfonic acid and a sulfonic acid surfactant in a volume ratio of 1: (0.1-0.3): (0.05-0.08) are fully mixed to obtain a mixed solution, and the mixed solution is mixed with a diluent in a volume ratio of 5:3 to obtain an extractant, wherein the organic acid extractant is one of cyclohexane acid, P204 and di(2,4,4-trimethylpentyl)phosphonic acid, and the sulfonic acid surfactant is one of sodium dodecyl sulfonate and sodium dodecylbenzene sulfonate;

[0012] S3, Extraction:

[0013] The extractant is an organic phase, and the acid solution of zirconium oxychloride is an aqueous phase. Extraction is performed by a countercurrent chromatograph, firstly the internal pipeline of the countercurrent chromatograph is filled with the organic phase, and then the organic phase and the aqueous phase are injected simultaneously, wherein the volume ratio of the organic phase to the aqueous phase during the simultaneous injection process is 2:(1-2.5), hafnium in the aqueous phase is extracted into the organic phase, and then the organic phase loaded with hafnium is washed by a detergent, wherein the flow ratio of the organic phase loaded with hafnium to the detergent is (1-8):1, the washing time is 30-50 minutes, and the washing temperature is 20-40°C, to obtain a hafnium-rich organic phase;

[0014] S4, stripping:

[0015] Using 1.0 mol / L ammonium carbonate solution as a stripping solution, the organic phase solution after step S3 is stripped by a countercurrent chromatograph to obtain a hafnium-rich aqueous solution, wherein the flow ratio of the ammonium carbonate solution to the organic phase solution is 1:3;

[0016] S5, Concentration:

[0017] Processing the hafnium-rich aqueous solution obtained in step S4 through a membrane to collect the obtained aqueous phase solution, thereby obtaining a purified hafnium-rich aqueous solution;

[0018] S6. Preparation of high purity hafnium oxide:

[0019] Ammonia water is added to the purified hafnium-rich aqueous solution to make the solution pH 8-10, and the solution is stirred for 1-1.5 hours. After complete precipitation, the solution is filtered and dried at 90-120°C for 10-13 hours to obtain hafnium precipitate, which is then calcined at 750-900°C in an air atmosphere for 5-7 hours to obtain high-purity hafnium oxide.

[0020] As a preferred technical solution of the present invention, in step S2, the diluent is sulfonated kerosene.

[0021] As a preferred technical solution of the present invention, in step S3, the detergent is a 2.5-3 mol / L sulfuric acid solution.

[0022] As a preferred technical solution of the present invention, in step S3, the conditions of the countercurrent chromatograph are: the main engine speed is 400-800 r / min, and the temperature is 20-50°C.

[0023] As a preferred technical solution of the present invention, in step S5, the preparation process of the membrane used for membrane treatment is as follows:

[0024] At 50-70° C. and nitrogen atmosphere, glutaraldehyde and polyvinylidene fluoride are dissolved in a solvent DMSO and stirred for 1-1.5 hours, and then hafnium tetrachloride and the extractant prepared in step S2 are added and stirred for 3-5 hours. After cooling to room temperature, the membrane solution is poured onto a glass plate, washed with water, and completely dried to obtain an ion imprinted membrane, wherein the concentration of hafnium tetrachloride is 40-80 mmol / L, and the mass ratio of glutaraldehyde, polyvinylidene fluoride and the extractant is (0.1-0.2):1:(1-2).

[0025] Dinonylnaphthalenesulfonic acid is added to the organic acid extractant. The molecular structure of dinonylnaphthalenesulfonic acid contains a long alkyl chain and a sulfonic acid group, which enables it to produce a synergistic effect with other organic acid extractants during the solvent extraction process. This synergistic effect can enhance the selectivity and extraction ability of the extractant for the target metal ion (hafnium), thereby improving the separation effect: dinonylnaphthalenesulfonic acid has excellent physical and chemical properties and stability. Its sulfonic acid group (SO3H) makes it highly polar and hydrophilic. At the same time, its long-chain alkyl part gives it a certain degree of hydrophobicity and oil solubility. During the extraction process, the sulfonic acid group of dinonylnaphthalenesulfonic acid can undergo a cation exchange reaction with the hafnium ion to form a stable extractant, while the organic acid extractant may form a complex or coordination compound with the metal hafnium ion through its carboxyl or phosphate group, thereby further promoting the extraction process. The mutual promotion of the two extractants during the extraction process optimizes the extraction efficiency.

[0026] At the same time, sulfonic acid surfactants are added to the extractant. Sulfonic acid surfactants have excellent solubility and miscibility, and can form a good mixed system with the extractant in the solvent, which helps the extractant to be evenly distributed in the solvent and improves the stability of the extraction system; at the same time, they can quickly reduce the surface tension in the solution, making the interface between the extractant and the water phase more active. This enhanced interfacial activity helps the extractant to better penetrate into the liquid and fully contact with the target substance, thereby changing the interfacial tension and interfacial charge distribution between the extractant and the water phase, and can make the extractant more effectively contact and react with the metal hafnium ions, thereby optimizing the extraction process and improving the extraction efficiency. The addition of sulfonic acid surfactants can also enhance the stability of the extraction system and reduce the occurrence of adverse phenomena such as emulsification and stratification during the extraction process, which helps to maintain the continuity and stability of the extraction process, improve production efficiency and product quality, and can adsorb and enrich the target substance, thereby improving the extraction effect of hafnium.

[0027] In addition, combined with membrane separation technology, further purification after stripping can help solve the problem that the traditional extraction process requires repeated extractions to achieve the required purity, optimize the process flow and improve the separation effect.

[0028] Beneficial effects of the present invention:

[0029] (1) In the present invention, the metal zirconium hafnium is extracted and separated by a solution separation method using a countercurrent chromatograph. The extractant used is a composite extractant composed of an organic acid extractant, dinonylnaphthalenesulfonic acid and a sulfonic acid surfactant. The synergistic effect of the three improves the separation efficiency of the metal zirconium hafnium. High-purity hafnium oxide is obtained by extraction, washing, stripping and purification. Compared with the traditional liquid-liquid extraction method, the countercurrent chromatograph is used for extraction and separation in a sealed container throughout the extraction and separation process, which avoids the occurrence of emulsification and ensures the continuity of production, thereby achieving continuous and effective extraction and separation and improving production efficiency.

[0030] (2) During the extraction process, the organic acid extractant of the present invention will preferentially extract hafnium into the organic phase, while zirconium will remain in the aqueous phase, since the complex ions of hafnium are more stable than those of zirconium. In this way, zirconium and hafnium are separated. At the same time, due to the difference in atomic radius between zirconium and hafnium, the complexing ability between zirconium and hafnium and the organic acid in the extractant is different. The organic acid in the composite extractant prepared by the present invention has a stronger complexing ability for hafnium atoms with a smaller atomic radius. Therefore, during the extraction process, the hafnium element in the zirconium and hafnium-containing mother liquor is preferentially extracted into the organic phase. During the stripping process, the hafnium-rich organic phase is stripped with ammonium carbonate. During the process, an ion exchange reaction will occur with the metal hafnium ions or complexes in the organic phase, so that the metal hafnium is transferred from the organic phase to the aqueous phase, and the ammonium carbonate and the ions generated by the dissociation will form stable complexes with the metal hafnium. These complexes have high solubility in the aqueous phase, which is beneficial to the extraction of the metal hafnium. Therefore, the hafnium will be stripped into the aqueous phase, and then the extraction agent will be used for secondary extraction and concentration to further improve the purity of the hafnium, thereby achieving the purpose of separating the zirconium and hafnium elements; and then high-purity hafnium oxide is obtained through alkalization, filtration and roasting, thereby achieving the purpose of extracting hafnium from the zirconium oxychloride mother liquor.

[0031] (3) In the solvent extraction system of the present invention, since hydrogen bonds can be formed between the organic acid extractant and dinonylnaphthalenesulfonic acid, the volatility of the organic acid extractant can be reduced, the loss of the extractant during use can be reduced, the solvent can be recovered, and the separation effect is good; and the separation efficiency can be improved by combining with membrane separation technology to obtain hafnium oxide with higher purity. DETAILED DESCRIPTION

[0032] In order to further illustrate the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the specific implementation methods, structures, features and effects of the present invention are described in detail below in combination with the embodiments.

[0033] In the following examples and comparative examples:

[0034] Zirconium oxychloride: purchased from Shanghai MacLean Biochemical Technology Co., Ltd., product number: Z888663;

[0035] Cyclohexane acid: purchased from Shanghai MacLean Biochemical Technology Co., Ltd., product number: N916923;

[0036] Dinonylnaphthalenesulfonic acid: purchased from Wuhan Fengtai Weiyuan Technology Co., Ltd.;

[0037] Sodium dodecyl sulfate: purchased from Guangdong Wengjiang Chemical Reagent Co., Ltd., product number: HJ01007;

[0038] Sodium dodecylbenzenesulfonate: purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.

[0039] P204: bis(2-ethylhexyl) phosphate, purchased from Wuhan Jiyesheng Chemical Co., Ltd.;

[0040] Di(2,4,4-trimethylpentyl)phosphonic acid: purchased from Changshu Xinte Chemical Co., Ltd.

[0041] Sulfonated kerosene: purchased from Hubei Kewode Chemical Co., Ltd.;

[0042] Ammonium carbonate: purchased from Shanghai Haohong Biopharmaceutical Technology Co., Ltd., product number: 1083437;

[0043] Glutaraldehyde: purchased from Hefei Tianjian Chemical Co., Ltd.

[0044] Polyvinylidene fluoride: purchased from Hubei Guangao Biotechnology Co., Ltd.;

[0045] Hafnium tetrachloride: purchased from Shanghai Jieshikai Biotechnology Co., Ltd.

[0046] Example 1

[0047] S1. Prepare the acid solution of zirconium oxychloride:

[0048] Dissolve zirconium oxychloride in water, add nitric acid and hydrochloric acid to make the acidity of the mixed solution 5 mol / L and the concentration of zirconium ions 20 g / L;

[0049] S2. Preparation of extraction agent:

[0050] The cyclohexane acid, dinonylnaphthalenesulfonic acid and sodium dodecylsulfonate in a volume ratio of 1:0.1:0.05 are fully mixed to obtain a mixed solution, and the mixed solution is mixed with sulfonated kerosene in a volume ratio of 5:3 to obtain an extractant;

[0051] S3, Extraction:

[0052] The extractant is an organic phase, and the acid solution of zirconium oxychloride is an aqueous phase. The extraction is performed by a countercurrent chromatograph. The organic phase is first filled into the internal pipeline of the countercurrent chromatograph, and then the organic phase and the aqueous phase are injected simultaneously, wherein the volume ratio of the organic phase to the aqueous phase during the simultaneous injection process is 2:1, and the hafnium in the aqueous phase is extracted into the organic phase. The organic phase loaded with hafnium is then washed with a 2.5 mol / L sulfuric acid solution, wherein the flow ratio of the organic phase loaded with hafnium to the washing agent is 1:1, the washing time is 30 minutes, and the washing temperature is 20°C, to obtain a hafnium-rich organic phase, wherein the conditions of the countercurrent chromatograph are a main engine speed of 400 r / min and a temperature of 20°C;

[0053] S4, stripping:

[0054] Using 1.0 mol / L ammonium carbonate solution as the stripping solution, the organic phase solution after step S4 is stripped by a countercurrent chromatograph to obtain a hafnium-rich aqueous solution, wherein the flow ratio of the ammonium carbonate solution to the organic phase solution is 1:3, and the conditions of the countercurrent chromatograph are a main engine speed of 500 r / min and a temperature of 30° C.;

[0055] S5, Concentration:

[0056] The hafnium-rich aqueous solution obtained in step S4 is treated with a membrane to collect the aqueous phase solution to obtain a purified hafnium-rich aqueous solution. The preparation process of the membrane used is as follows:

[0057] At 50° C. and nitrogen atmosphere, glutaraldehyde and polyvinylidene fluoride were dissolved in a solvent DMSO and stirred for 1 h, and then hafnium tetrachloride and the extractant prepared in step S2 were added and stirred for 3 h. After cooling to room temperature, the membrane solution was poured onto a glass plate, washed with water, and completely dried to prepare an ion imprinted membrane, wherein the concentration of hafnium tetrachloride was 40 mmol / L, and the mass ratio of glutaraldehyde, polyvinylidene fluoride and the extractant was 0.1:1:1;

[0058] S6. Preparation of high purity hafnium oxide:

[0059] Ammonia water was added to the purified hafnium-rich aqueous solution to make the solution pH 8, and the solution was stirred for 1 hour. After complete precipitation, the solution was filtered and dried at 90°C for 10 hours to obtain hafnium precipitate, which was calcined at 750°C in air atmosphere for 5 hours to obtain high-purity hafnium oxide.

[0060] Example 2

[0061] S1. Prepare the acid solution of zirconium oxychloride:

[0062] Dissolve zirconium oxychloride in water, add nitric acid and hydrochloric acid to make the acidity of the mixed solution 6 mol / L and the concentration of zirconium ions 30 g / L;

[0063] S2. Preparation of extraction agent:

[0064] P204, dinonylnaphthalenesulfonic acid and sodium dodecylbenzenesulfonate in a volume ratio of 1:0.2:0.07 are fully mixed to obtain a mixed solution, and the mixed solution is mixed with sulfonated kerosene in a volume ratio of 5:3 to obtain an extractant;

[0065] S3, Extraction:

[0066] The extractant is an organic phase, and the acid solution of zirconium oxychloride is an aqueous phase. The extraction is performed through a countercurrent chromatograph. The organic phase is first filled with the internal pipeline of the countercurrent chromatograph, and then the organic phase and the aqueous phase are injected simultaneously, wherein the volume ratio of the organic phase to the aqueous phase during the simultaneous injection process is 2:2, and the hafnium in the aqueous phase is extracted into the organic phase. Then, the organic phase loaded with hafnium is washed with a 2.8 mol / L sulfuric acid solution, wherein the flow ratio of the organic phase loaded with hafnium to the washing agent is 4:1, the washing time is 40 minutes, and the washing temperature is 30°C, to obtain a hafnium-rich organic phase, wherein the conditions of the countercurrent chromatograph are that the main engine speed is 600 r / min and the temperature is 30°C;

[0067] S4, stripping:

[0068] The organic phase solution after step S4 is stripped by a countercurrent chromatograph using a 1.0 mol / L ammonium carbonate solution as a stripping solution to obtain a hafnium-rich aqueous solution, wherein the flow ratio of the ammonium carbonate solution to the organic phase solution is 1:3, and the conditions of the countercurrent chromatograph are a main engine speed of 700 r / min and a temperature of 35° C.;

[0069] S5, Concentration:

[0070] The hafnium-rich aqueous solution obtained in step S4 is treated with a membrane to collect the aqueous phase solution to obtain a purified hafnium-rich aqueous solution. The preparation process of the membrane used is as follows:

[0071] At 60° C. and nitrogen atmosphere, glutaraldehyde and polyvinylidene fluoride were dissolved in a solvent DMSO and stirred for 1.2 h, and then hafnium tetrachloride and the extractant prepared in step S2 were added and stirred for 4 h. After cooling to room temperature, the membrane solution was poured onto a glass plate, washed with water, and completely dried to prepare an ion imprinted membrane, wherein the concentration of hafnium tetrachloride was 60 mmol / L, and the mass ratio of glutaraldehyde, polyvinylidene fluoride and the extractant was 0.15:1:1.5;

[0072] S6. Preparation of high purity hafnium oxide:

[0073] Ammonia water was added to the concentrated hafnium-rich aqueous solution to make the solution pH 9, and the solution was stirred for 1.3 hours. After complete precipitation, the solution was filtered and dried at 100°C for 12 hours to obtain hafnium precipitate, which was calcined at 850°C in air atmosphere for 6 hours to obtain high-purity hafnium oxide.

[0074] Example 3

[0075] S1. Prepare the acid solution of zirconium oxychloride:

[0076] Dissolve zirconium oxychloride in water, add nitric acid and hydrochloric acid to make the acidity of the mixed solution 8 mol / L and the concentration of zirconium ions 50 g / L;

[0077] S2. Preparation of extraction agent:

[0078] Di(2,4,4-trimethylpentyl)phosphonic acid, dinonylnaphthalenesulfonic acid and sodium dodecylsulfonate in a volume ratio of 1:0.3:0.08 are fully mixed to obtain a mixed solution, and the mixed solution is mixed with sulfonated kerosene in a volume ratio of 5:3 to obtain an extractant;

[0079] S3, Extraction:

[0080] The extractant is an organic phase, and the acid solution of zirconium oxychloride is an aqueous phase. The extraction is performed by a countercurrent chromatograph. The organic phase is first filled into the internal pipeline of the countercurrent chromatograph, and then the organic phase and the aqueous phase are injected simultaneously, wherein the volume ratio of the organic phase to the aqueous phase during the simultaneous injection process is 2:2.5, and the hafnium in the aqueous phase is extracted into the organic phase. The organic phase loaded with hafnium is then washed with a 3 mol / L sulfuric acid solution, wherein the flow ratio of the organic phase loaded with hafnium to the washing agent is 8:1, the washing time is 50 minutes, and the washing temperature is 40°C, to obtain a hafnium-rich organic phase, wherein the conditions of the countercurrent chromatograph are a main engine speed of 800 r / min and a temperature of 50°C;

[0081] S4, stripping:

[0082] The organic phase solution after step S4 is stripped by a countercurrent chromatograph using a 1.0 mol / L ammonium carbonate solution as a stripping solution to obtain a hafnium-rich aqueous solution, wherein the flow ratio of the ammonium carbonate solution to the organic phase solution is 1:3, and the conditions of the countercurrent chromatograph are a main engine speed of 800 r / min and a temperature of 45° C.;

[0083] S5, Concentration:

[0084] The hafnium-rich aqueous solution obtained in step S4 is treated with a membrane to collect the aqueous phase solution to obtain a purified hafnium-rich aqueous solution. The preparation process of the membrane used is as follows:

[0085] At 70°C and nitrogen atmosphere, glutaraldehyde and polyvinylidene fluoride were dissolved in a solvent DMSO and stirred for 1.5 hours, and then hafnium tetrachloride and the extractant prepared in step S2 were added and stirred for 5 hours. After cooling to room temperature, the membrane solution was poured onto a glass plate, washed with water, and completely dried to prepare an ion imprinted membrane, wherein the concentration of hafnium tetrachloride was 80 mmol / L, and the mass ratio of glutaraldehyde, polyvinylidene fluoride and the extractant was 0.2:1:2;

[0086] S6. Preparation of high purity hafnium oxide:

[0087] Ammonia water was added to the concentrated hafnium-rich aqueous solution to make the solution pH 10, and the solution was stirred for 1.5 hours. After complete precipitation, the solution was filtered and dried at 120°C for 13 hours to obtain hafnium precipitate, which was calcined at 900°C in air atmosphere for 7 hours to obtain high-purity hafnium oxide.

[0088] Comparative Example 1

[0089] The difference between Comparative Example 1 and Example 2 is that in Comparative Example 1, no dinonylnaphthalenesulfonic acid is added to the extractant, and the other operations are the same.

[0090] Comparative Example 2

[0091] The difference between Comparative Example 2 and Example 2 is that the extractant in Comparative Example 2 is only P204, and the other operations are the same.

[0092] Comparative Example 3

[0093] The difference between Comparative Example 3 and Example 2 is that sodium dodecylbenzene sulfonate is not added in Comparative Example 3, and the other operations are the same.

[0094] Comparative Example 4

[0095] The difference between Comparative Example 4 and Example 2 is that step S5 is not performed in Comparative Example 4, and the remaining operations are the same.

[0096] Performance Testing:

[0097] The concentration of hafnium oxide prepared in the examples and comparative examples was measured according to the standard GB / T 23942-2009 "General Rules for Inductively Coupled Plasma Atomic Emission Spectrometry of Chemical Reagents", and the results are shown in the following table:

[0098]

[0099] By the process of the present invention, high-purity hafnium can be extracted and separated from zirconium oxychloride mother liquor, and hafnium oxide with a purity greater than 99.999% can be obtained by alkalization and roasting. The zirconium content in the hafnium oxide prepared in Examples 1-3 is less than the national standard (not more than 3%).

[0100] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technical personnel in this field can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any brief modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A process for extracting and separating hafnium from zirconium oxychloride mother liquor, characterized in that: The following steps are involved: S1. Prepare the acid solution of zirconium oxychloride: Dissolve zirconium oxychloride in water, add nitric acid and hydrochloric acid to make the acidity of the mixed solution 5-8 mol / L and the concentration of zirconium ions 20-50 g / L; S2. Preparation of extraction agent: An organic acid extractant, dinonylnaphthalenesulfonic acid and a sulfonic acid surfactant in a volume ratio of 1: (0.1-0.3): (0.05-0.08) are fully mixed to obtain a mixed solution, and the mixed solution is mixed with a diluent in a volume ratio of 5:3 to obtain an extractant, wherein the organic acid extractant is one of cyclohexane acid, P204 and di(2,4,4-trimethylpentyl)phosphonic acid, and the sulfonic acid surfactant is one of sodium dodecyl sulfonate and sodium dodecylbenzene sulfonate; S3, Extraction: The extractant is an organic phase, and the acid solution of zirconium oxychloride is an aqueous phase. Extraction is performed by a countercurrent chromatograph, firstly the internal pipeline of the countercurrent chromatograph is filled with the organic phase, and then the organic phase and the aqueous phase are injected simultaneously, wherein the volume ratio of the organic phase to the aqueous phase during the simultaneous injection process is 2:(1-2.5), hafnium in the aqueous phase is extracted into the organic phase, and then the organic phase loaded with hafnium is washed by a detergent, wherein the flow ratio of the organic phase loaded with hafnium to the detergent is (1-8):1, the washing time is 30-50 minutes, and the washing temperature is 20-40°C, to obtain a hafnium-rich organic phase; S4, stripping: Using 1.0 mol / L ammonium carbonate solution as a stripping solution, the organic phase solution after step S3 is stripped by a countercurrent chromatograph to obtain a hafnium-rich aqueous solution, wherein the flow ratio of the ammonium carbonate solution to the organic phase solution is 1:3; S5, Concentration: Processing the hafnium-rich aqueous solution obtained in step S4 through a membrane to collect the obtained aqueous phase solution, thereby obtaining a purified hafnium-rich aqueous solution; S6. Preparation of high purity hafnium oxide: Ammonia water is added to the purified hafnium-rich aqueous solution to make the solution pH 8-10, and the solution is stirred for 1-1.5 hours. After complete precipitation, the solution is filtered and dried at 90-120°C for 10-13 hours to obtain hafnium precipitate, which is then calcined at 750-900°C in an air atmosphere for 5-7 hours to obtain high-purity hafnium oxide.

2. The process for extracting and separating hafnium from zirconium oxychloride mother liquor according to claim 1, characterized in that: In step S2, the diluent is sulfonated kerosene.

3. The process for extracting and separating hafnium from zirconium oxychloride mother liquor according to claim 1, characterized in that: In step S3, the detergent is a 2.5-3 mol / L sulfuric acid solution.

4. The process for extracting and separating hafnium from zirconium oxychloride mother liquor according to claim 1, characterized in that: In step S3, the conditions of the countercurrent chromatograph are: the main engine speed is 400-800 r / min, and the temperature is 20-50°C.

5. The process for extracting and separating hafnium from zirconium oxychloride mother liquor according to claim 1, characterized in that: In step S5, the preparation process of the membrane used for the membrane treatment is as follows: At 50-70° C. and nitrogen atmosphere, glutaraldehyde and polyvinylidene fluoride are dissolved in a solvent DMSO and stirred for 1-1.5 hours, and then hafnium tetrachloride and the extractant prepared in step S2 are added and stirred for 3-5 hours. After cooling to room temperature, the membrane solution is poured onto a glass plate, washed with water, and completely dried to prepare an ion imprinted membrane, wherein the concentration of hafnium tetrachloride is 40-80 mmol / L, and the mass ratio of glutaraldehyde, polyvinylidene fluoride and the extractant is (0.1-0.2):1:(1-2).

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