Process system for efficiently separating hafnium and zirconium through ionic imprinting membrane coupling novel solvent method

Abstract

The invention provides a process system for efficiently separating hafnium and zirconium based on an ionic imprinting membrane coupling novel solvent method, and relates to the technical field of separation and preparation of hafnium and zirconium metal resources. According to the technology, firstly, hafnium in a zirconium oxychloride solution system is enriched by utilizing a hafnium-zirconium ionic membrane, so that the hafnium-zirconium ratio of an enriched phase (extraction phase) is increased to 6: 20 from the original 0.6-0.8: 100, the hafnium content (hafnium oxide mass) in a barren solution phase (water phase) is reduced to 0.008% or below, zirconium ions are efficiently purified, the total amount of the obtained rich solution (extraction phase) is reduced to 5.0% of the total amount of a raw material solution, and the purity of the obtained rich solution (extraction phase) is improved. According to the method, the problems of high acidity, large corrosion to equipment, incapability of continuous production and low efficiency of TBP-HNO3-HCl extraction are solved, zirconium oxide and hafnium oxide are respectively obtained after a loaded organic phase and raffinate are respectively treated after TBP extraction, the extraction efficiency is high, efficient utilization of flue gas waste heat can be realized, and the method is suitable for industrial production. Meanwhile, the energy consumption of an extraction and calcination system is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of separation and preparation of hafnium-zirconium metal resources, in particular to an ion-imprinted membrane coupled with a novel solvent method and a highly efficient process system for separating hafnium-zirconium. Background Art

[0002] Hafnium is an indispensable core material in the atomic energy industry. In nature, there are generally no independent hafnium minerals, but it is dispersed in zirconium minerals. The difference between zirconium and hafnium in thermal neutron capture cross-sections is very large, resulting in completely different applications of zirconium and hafnium in the atomic energy field. Therefore, the separation of zirconium and hafnium is of great significance to the atomic energy industry.

[0003] The hafnium content in zirconium ore is 0.5% to 3%, generally not exceeding 2%. Hafnium is located in the fourth subgroup of the periodic table, after zirconium. Its outermost electrons are arranged in the same order as zirconium. At the same time, it is restricted by the "lanthanide contraction" effect. The physical and chemical properties of zirconium and hafnium are extremely similar, which poses great challenges to the separation of zirconium and hafnium.

[0004] Many methods have been studied for the separation of zirconium and hafnium. Among them, the solvent extraction method is widely used in the separation of zirconium and hafnium due to its advantages such as easy selection of equipment materials, low cost, continuous operation, and easy solution of "three wastes". At present, there are mainly three processes for the separation of zirconium and hafnium: MIBK-NH4SCN method, TBP-HNO3-HCl method, TOA / N 235 -H2SO4 method; MIBK-NH4SCN system is a process for extracting hafnium first. This method has high extraction efficiency, but industrial wastewater and waste gas are discharged, which is very harmful to the environment. The TBP-HNO3-HCl mixed acid system requires high extraction acidity, which is highly corrosive to equipment and cannot be produced continuously. TOA / N 235 -H2SO4 method has simple equipment, small investment and little pollution, but it has disadvantages such as low zirconium and hafnium separation coefficient and limited extraction capacity. Summary of the invention

[0005] 1. Technical issues to be solved

[0006] In view of the shortcomings of the prior art, the present invention provides an ion-imprinted membrane coupled with a novel solvent method for efficient separation of hafnium and zirconium, which solves the problems of high acidity, high corrosion to equipment, and inability to produce continuously in the TBP-HNO3-HCl method. At the same time, after the TBP extraction, the loaded organic phase and the raffinate are treated separately to obtain zirconium oxide and hafnium oxide, respectively. Not only is the extraction efficiency high, but also the waste liquid, waste water, and waste gas can be recovered and recycled through the supporting HCl recovery device, waste acid liquid incinerator, waste ion membrane degradation device, acid gas absorption tower, neutralization tank, purification and concentration tank, filter press, etc.

[0007] (II) Technical solution

[0008] To achieve the above objectives, the present invention is implemented through the following technical solutions: an ion imprinted membrane coupled with a new solvent method for efficient separation of hafnium and zirconium process system, comprising the following separation steps:

[0009] S1. Add industrial-grade zirconium oxychloride and other hafnium-zirconium-containing raw materials and deionized water into a zirconium oxychloride dissolving tank, and add dilute hydrochloric acid to inhibit the hydrolysis of the raw materials to prepare a nearly saturated solution of zirconium oxychloride octahydrate.

[0010] S2. Preparation of hafnium ion imprinted membrane:

[0011] (1) Preparation of the ternary complex: a certain amount of hafnium oxychloride octahydrate, tributyl phosphate and 4-vinylpyridine were added to a 2-methoxyethanol solution and stirred for 3 hours under the protection of a frozen ice bath to form a ternary complex;

[0012] (2) Polymerization reaction: a certain amount of styrene, divinylbenzene and azobisisobutyronitrile were added to the above ternary complex solution, nitrogen was passed through the solution for 10 minutes under the protection of a frozen ice bath, the solution was sealed, stirred for 30 minutes, and reacted in a constant temperature water bath at about 80° C. for 3 hours to obtain a white block polymer;

[0013] (3) Post-treatment of the polymer: grind the block polymer, sieve with a sieve smaller than 75 μm, bake in an oven at 80° C. for 2 hours, soak in 100 mL of a 1:1 hydrochloric acid solution for 6 hours, then rinse with dilute hydrochloric acid several times until no hafnium ions are detected in the eluent, and dry in an oven at about 80° C. to obtain a hafnium ion imprinted polymer;

[0014] S3. Controlling the preparation of polymers:

[0015] The preparation process of the control polymer was similar to that of the imprinted polymer, except that zirconium oxychloride octahydrate was not added;

[0016] S4, combining the above membrane materials into a 6-stage hafnium ion imprinted membrane extraction system;

[0017] S5, treating the hafnium oxychloride solution with the above-mentioned 6-stage hafnium ion imprinted membrane extraction system;

[0018] S6. Reuse the new extractant to extract and purify the zirconium in the rich liquid phase:

[0019] (1) tributyl phosphate and ionic liquid are used as extractants and kerosene is used as a diluent to prepare an organic phase; then the organic phase is mixed with an acid and subjected to countercurrent acidification in a centrifugal extractor;

[0020] (2) using the enriched phase as a raw material, adding it into deionized water to dissolve it, and then adding hydrochloric acid and nitric acid to prepare a feed solution containing zirconium and hafnium;

[0021] (3) subjecting the acidified organic phase and the liquid containing zirconium and hafnium prepared in step (2) of S6 to 10-stage countercurrent extraction in a liquid-liquid ultragravity extractor;

[0022] S7, stripping all zirconium-containing organic phases with water, and then hydrolyzing and calcining to obtain nuclear-grade zirconium oxide;

[0023] S8. The hafnium-containing raffinate is subjected to 6-stage extraction enrichment with P2O4, and then stripped, hydrolyzed and calcined to obtain nuclear-grade hafnium oxide.

[0024] Preferably, the process method requires configuration of ion imprinted membrane extraction reactor, liquid-liquid ultragravity extraction reactor, clarification tank, crystallization heat exchanger, storage tank, hydrolysis tank, evaporator, filter press, dryer, high temperature calcining kiln, grinder, absorption tower and other process equipment and environmental protection equipment.

[0025] Preferably, in S2, the preparation of the ternary complex requires stirring for at least 3 hours under the protection of a frozen ice bath to form the ternary complex.

[0026] Preferably, in S5, after the hafnium oxychloride solution is treated with a 6-stage hafnium ion imprinted membrane extraction system, the zirconium ions are efficiently purified, and the hafnium-zirconium ratio of the enriched phase is increased from the original 0.6-0.8:100 to 6:20, while the hafnium content in the lean phase has dropped to below 0.008%, and the total amount of the remaining enriched phase is less than 5.0% of the total amount of the raw material solution.

[0027] Preferably, in S6, the organic phase is mixed with an acid and the ionic liquid subjected to countercurrent acidification in a centrifugal extractor is a hydrophobic quaternary ammonium salt having a structure of [NRnH4 -n ][X], where X is Cl - , NO 3- ,PO4 3- One or more of these are acceptable.

[0028] (III) Beneficial effects

[0029] The present invention provides an ion imprinting membrane coupled with a novel solvent method for efficiently separating hafnium and zirconium. It has the following beneficial effects:

[0030] The invention solves the problems of high acidity, great corrosion to equipment and inability to produce continuously and other low efficiency problems of TBP-HNO3-HCl extraction, and realizes that zirconium oxide and hafnium oxide are obtained respectively after separate treatment of the loaded organic phase and the raffinate after TBP extraction. Not only is the extraction efficiency high, but also the waste liquid, waste water and waste gas can be recovered and recycled through the supporting HCl recovery device, waste acid liquid incinerator, waste ion membrane degradation device, acid gas absorption tower, neutralization tank, purification and concentration tank, filter press, etc., and the efficient utilization of flue gas waste heat is realized, while the energy consumption of the extraction and calcination system is reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a process flow chart of the present invention. DETAILED DESCRIPTION

[0032] The technical solutions in the embodiments of the present invention are described clearly and completely. 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.

[0033] Example:

[0034] The embodiment of the present invention provides an ion imprinting membrane coupled with a novel solvent method for efficiently separating hafnium and zirconium, comprising the following separation steps:

[0035] S1. Adding industrial-grade zirconium oxychloride and other hafnium-zirconium-containing raw materials and deionized water into a zirconium oxychloride dissolving tank, and adding dilute hydrochloric acid to inhibit the hydrolysis of the raw materials, to prepare a nearly saturated solution of zirconium oxychloride octahydrate;

[0036] S2. Preparation of hafnium ion imprinted membrane:

[0037] (1) Preparation of the ternary complex: a certain amount of hafnium oxychloride octahydrate, tributyl phosphate (TBP) and 4-vinylpyridine (VP) were added to a 2-methoxyethanol solution and stirred for 3 hours under the protection of a frozen ice bath to form a ternary complex;

[0038] (2) Polymerization reaction: a certain amount of styrene (Sty), divinylbenzene (DVB) and azobisisobutyronitrile (AIBN) were added to the above ternary complex solution, nitrogen was passed through the solution for 10 minutes under the protection of a frozen ice bath, the solution was sealed, stirred for 30 minutes, and reacted in a constant temperature water bath at about 80°C for 3 hours to obtain a white block polymer;

[0039] (3) Post-treatment of the polymer: grind the block polymer, sieve with a sieve smaller than 75 μm, bake in an oven at 80°C for 2 hours, soak in 100 mL of a 1:1 hydrochloric acid solution for 6 hours, then rinse with dilute hydrochloric acid several times until no hafnium ions are detected in the eluent, and dry in an oven at about 80°C to obtain hafnium ion imprinted polymers (Hf-IIPs);

[0040] S3. Controlling the preparation of polymers:

[0041] a. Preparation of ternary complex: a certain amount of tributyl phosphate (TBP) and 4-vinylpyridine (VP) were added to 2-methoxyethanol solution and stirred for 3 hours under the protection of a frozen ice bath to form a ternary complex;

[0042] b. Polymerization reaction: a certain amount of styrene (Sty), divinylbenzene (DVB) and azobisisobutyronitrile (AIBN) were added to the above ternary complex solution, nitrogen was passed through the solution for 10 minutes under the protection of a frozen ice bath, the solution was sealed, stirred for 30 minutes, and reacted in a constant temperature water bath at about 80°C for 3 hours to obtain a white block polymer;

[0043] c. Post-treatment of the polymer: grind the block polymer, sieve with a sieve smaller than 75 μm, bake in an oven at about 80° C. for 2 hours, soak in 100 mL of a 1:1 hydrochloric acid solution for 6 hours, then rinse with dilute hydrochloric acid several times until no hafnium ions are detected in the eluent, and dry in an oven at about 80° C. to obtain a polymer (CPsI);

[0044] S4, combining the above membrane materials into a 6-stage hafnium ion imprinted membrane extraction system;

[0045] S5, treating the hafnium oxychloride solution with the above-mentioned 6-stage hafnium ion imprinted membrane extraction system, after which the hafnium-zirconium ratio of the enriched phase (extracted phase) is increased from the original 0.6-0.8:100 to 6:20, while the hafnium content (hafnium oxide mass) in the lean liquid phase (aqueous phase) is reduced to less than 0.008%, and the total amount of the remaining enriched (extracted phase) phase is less than 5.0% of the total amount of the raw material liquid;

[0046] S6. Using the new extractant to extract and purify the zirconium in the rich liquid phase (extraction phase):

[0047] (1) tributyl phosphate and ionic liquid are used as extractants and kerosene is used as a diluent to prepare an organic phase; then the organic phase is mixed with nitric acid and subjected to countercurrent acidification in a centrifugal extractor;

[0048] (2) using the enriched phase as a raw material, adding it into deionized water to dissolve it, and then adding hydrochloric acid and nitric acid to prepare a feed solution containing zirconium and hafnium;

[0049] (3) subjecting the acidified organic phase and the liquid containing zirconium and hafnium prepared in step (2) of S6 to 10-stage countercurrent extraction in a liquid-liquid ultragravity extractor;

[0050] S7, stripping all zirconium-containing organic phases (including lean liquid phase or water phase) with water, and then hydrolyzing and calcining to obtain nuclear-grade zirconium oxide;

[0051] S8. The hafnium-containing raffinate is subjected to 6-stage extraction enrichment with P2O4, and then stripped, hydrolyzed and calcined to obtain nuclear-grade hafnium oxide.

[0052] The process method requires the configuration of ion imprinted membrane extraction reactor, liquid-liquid ultra-gravity extraction reactor, clarification tank, crystallization heat exchanger, storage tank, hydrolysis tank, evaporator, filter press, dryer, high-temperature calcining kiln, grinder, absorption tower and other process equipment and environmental protection equipment.

[0053] In S2, the preparation of the ternary complex requires stirring for at least 3 hours under the protection of a refrigerated ice bath to form the ternary complex.

[0054] In S5, after the hafnium oxychloride solution was treated with a 6-stage hafnium ion imprinted membrane extraction system, the zirconium ions were efficiently purified, and the hafnium-zirconium ratio of the enriched phase was increased from the original 0.6-0.8:100 to 6:20, while the hafnium content in the lean phase was reduced to below 0.008%, and the total amount of the remaining enriched phase was less than 5.0% of the total amount of the raw material solution.

[0055] In S6, the ionic liquid subjected to countercurrent acidification in the centrifugal extractor is a hydrophobic quaternary ammonium salt having the structure [NRnH4 -n ][X], where X can be Cl - , NO 3- ,PO4 3- One or more of these are acceptable.

[0056] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. An ion imprinted membrane coupled with a novel solvent method for efficient separation of hafnium and zirconium, characterized in that: The separation steps include: S1. Adding industrial-grade zirconium oxychloride and other hafnium-zirconium-containing raw materials and deionized water into a zirconium oxychloride dissolving tank, and adding dilute hydrochloric acid to inhibit the hydrolysis of the raw materials, to prepare a nearly saturated solution of zirconium oxychloride octahydrate; S2. Preparation of hafnium ion imprinted membrane: (1) Preparation of the ternary complex: a certain amount of hafnium oxychloride octahydrate, tributyl phosphate and 4-vinylpyridine were added to a 2-methoxyethanol solution and stirred for 3 hours under the protection of a frozen ice bath to form a ternary complex; (2) Polymerization reaction: a certain amount of styrene, divinylbenzene and azobisisobutyronitrile were added to the above ternary complex, nitrogen was passed through the mixture for 10 minutes under the protection of a frozen ice bath, the mixture was sealed, stirred for 30 minutes, and reacted in a constant temperature water bath at about 80° C. for 3 hours to obtain a white block polymer; (3) Post-treatment of the polymer: grind the block polymer, sieve it with a sieve smaller than 75 μm, bake it in an oven at 80° C. for 2 hours, soak it in 100 mL of 1:1 hydrochloric acid solution for 6 hours, then rinse it with dilute hydrochloric acid several times until no hafnium ions are detected in the eluent, and dry it in an oven at about 80° C. to obtain a hafnium ion imprinted polymer; S3. Controlling the preparation of polymers: The control polymer was prepared similarly to the imprinted polymer, except that zirconium oxychloride octahydrate was not added; S4, combining the above membrane materials into a 6-stage hafnium ion imprinted membrane extraction system; S5, treating the hafnium oxychloride solution with the above-mentioned 6-stage hafnium ion imprinted membrane extraction system; S6. Reuse the new extractant to extract and purify the zirconium in the rich liquid phase: (1) tributyl phosphate and ionic liquid are used as extractants and kerosene is used as a diluent to prepare an organic phase, and then the organic phase is mixed with an acid and subjected to countercurrent acidification in a centrifugal extractor; (2) using the enriched phase as a raw material, adding it into deionized water to dissolve it, and then adding hydrochloric acid and nitric acid to prepare a feed solution containing zirconium and hafnium; (3) subjecting the acidified organic phase and the liquid containing zirconium and hafnium prepared in step (2) of S6 to 10-stage countercurrent extraction in a liquid-liquid ultragravity extractor; S7, stripping all zirconium-containing organic phases with water, and then hydrolyzing and calcining to obtain nuclear-grade zirconium oxide; S8. The hafnium-containing raffinate is subjected to 6-stage extraction enrichment with P2O4, and then stripped, hydrolyzed and calcined to obtain nuclear-grade hafnium oxide.

2. According to the above claims, the ion imprinted membrane coupled with a novel solvent method for efficient separation of hafnium and zirconium process system is characterized by: The process method requires the configuration of ion imprinting membrane extraction reactor, liquid-liquid ultra-gravity extraction reactor, clarification tank, crystallization heat exchanger, storage tank, hydrolysis tank, evaporator, filter press, dryer, high-temperature calcining kiln, grinding mill, absorption tower and other process equipment and environmental protection equipment.

3. The ion-imprinted membrane coupled novel solvent method high-efficiency separation system of hafnium and zirconium according to claim 1 is characterized by: In S2, the preparation of the ternary complex requires stirring for at least 3 hours under the protection of a frozen ice bath to form the ternary complex.

4. The ion imprinted membrane coupled novel solvent method high efficiency separation system of hafnium and zirconium according to claim 1, characterized in that: In S5, after the hafnium oxychloride solution is treated with a 6-stage hafnium ion imprinted membrane extraction system, the zirconium ions are efficiently purified, and the hafnium-zirconium ratio of the enriched phase is increased from the original 0.6-0.8:100 to 6:20, while the hafnium content in the lean liquid phase has dropped to below 0.008%, and the total amount of the remaining enriched phase is less than 5.0% of the total amount of the raw material liquid.

5. The ion-imprinted membrane coupled novel solvent method highly efficient separation system of hafnium and zirconium according to claim 1, characterized in that: In S6, the ionic liquid subjected to countercurrent acidification in the centrifugal extractor is a hydrophobic quaternary ammonium salt having a structure of [NRnH4 -n ][X], where X can be Cl - , NO 3- ,PO4 3- One or more of these are acceptable.

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