Method for separating hafnium and niobium

Abstract

The invention relates to the technical field of metallurgy, and provides a method for extracting and separating hafnium and niobium. The method specifically comprises the following steps: carrying out extraction treatment on an extraction stock solution in an extraction agent, and carrying out separation treatment on an extraction treatment product so as to separate hafnium and niobium, wherein the extraction stock solution comprises a hafnium-containing compound to be separated, niobium to be separated and an acidity regulator. The method provided by the invention can effectively realize separation of hafnium and niobium, has the advantages of simplicity and convenience in operation, low energy consumption and smaller environmental harm, and is suitable for large-scale application.

Description

Technical Field

[0001] This application relates to the field of metallurgical technology, and more specifically, to a method for separating hafnium and niobium. Background Technology

[0002] Hafnium (Hf) and niobium (Nb) are important rare metal elements that play a vital role in modern high-end industries. Hafnium possesses excellent mechanical strength, high-temperature resistance, and corrosion resistance, and is widely used in aerospace thermal protection systems, control rod materials for nuclear reactors, and as a key raw material for next-generation semiconductors.

[0003] Hafnium and niobium often coexist in nature and share certain similar chemical properties. Traditional separation techniques, such as chemical precipitation, are cumbersome, have low separation efficiency, and easily generate large amounts of wastewater. Ion exchange methods have limited adsorption capacity, are time-consuming and costly when treating high-concentration hafnium solutions, making them unsuitable for large-scale industrial production. Liquid-liquid extraction offers advantages such as high production capacity, simple equipment, and ease of automation. However, existing extraction technologies suffer from insufficient selectivity for niobium when treating high-concentration hafnium and low-concentration niobium solutions, leading to residues. This makes it difficult to meet the industrial requirements of high separation efficiency, low niobium residue, and no hafnium loss. Furthermore, some extractants are highly toxic, cause significant environmental damage, and have high processing costs.

[0004] Therefore, methods for separating hafnium and niobium still need to be developed. Summary of the Invention

[0005] This application aims to address, to some extent, the problems existing in current separation technologies. To this end, this application proposes a method for separating hafnium and niobium. This method can effectively separate hafnium and niobium, and has the advantages of simple operation, low energy consumption, and minimal environmental impact, making it suitable for large-scale application.

[0006] In one aspect of this application, a method for separating hafnium and niobium is provided. According to an embodiment of this application, the method includes: extracting a raw extract in an extractant, the raw extract comprising a hafnium-containing compound to be separated, niobium to be separated, and an acidity regulator; and separating the extraction product to separate the hafnium and niobium.

[0007] According to the method for separating hafnium and niobium according to embodiments of this application, the hafnium-containing compounds in the extraction solution include hafnium dioxide, hafnium chloride, and industrial-grade hafnium-containing compounds dissolved in the acidity regulator solution, forming hafnium-containing elemental components. The niobium to be separated in the extraction solution includes niobium complexes, niobium ions, and other niobium-containing elemental components dissolved in the acidity regulator. Due to the difference in solubility of hafnium and niobium in the extractant system and the aqueous phase, niobium is collected in the extractant and efficiently separated from hafnium. Furthermore, since existing separation technologies have the problem of high hafnium concentration and low niobium concentration in the separated feed solution, but the residual niobium concentration after extraction is difficult to reduce to an extremely low level, the inventors have discovered through in-depth research that primary amine extractants, tertiary amine extractants, methyltrioctylammonium chloride, and tri-n-octylamine can be used as extractants to extract the coordination anionic compounds formed by the coordination of niobium ions with the anions of the acidity regulator, while the content of the coordination anionic compounds formed by hafnium is extremely low, thereby achieving effective separation of hafnium and niobium.

[0008] According to embodiments of this application, the above-described method for separating hafnium and niobium may also have the following additional technical features: According to embodiments of this application, the extraction solution is obtained by dissolving a sample containing the hafnium-containing compound to be separated in an acidity adjuster. In some embodiments, the dissolution process involves adjusting the concentration of the dissolved product.

[0009] According to embodiments of this application, the acidity regulator includes at least one of nitric acid, hydrochloric acid, sulfuric acid, phosphoric acid, and perchloric acid. By adding the acidity regulator, an acidic environment is provided for the extraction process, allowing niobium ions to form coordination anionic compounds with the anions of the acidity regulator, thereby being extracted and separated by the extractant. Simultaneously, the content of coordination anionic compounds formed by hafnium in the acidic environment is ensured to be extremely low, thus achieving effective separation of hafnium and niobium.

[0010] According to embodiments of this application, the hafnium-containing compound includes at least one of hafnium dioxide, hafnium chloride, and industrial-grade hafnium-containing liquid.

[0011] According to embodiments of this application, the dissolution process is carried out at a stirring rate of 150 rpm to 200 rpm and a stirring temperature of 20°C to 30°C. This stirring process fully dissolves the hafnium-containing compound in the extraction solution, effectively improving the separation of hafnium and niobium.

[0012] According to embodiments of this application, the concentration of hafnium in the extraction solution is 1000 ppm to 300000 ppm. In some embodiments, the concentration of hafnium in the extraction solution is 1000 ppm, 5000 ppm, 10000 ppm, 20000 ppm, 50000 ppm, 100000 ppm, 150000 ppm, 200000 ppm, 250000 ppm, or 300000 ppm. The hafnium concentration in the extraction solution meeting the above conditions can effectively improve the separation effect of hafnium and niobium.

[0013] According to embodiments of this application, the concentration of the acidity regulator in the extraction solution is 0.5 mol / L to 5 mol / L. In some embodiments, the acidity regulator in the extraction solution is 0.5 mol / L, 1 mol / L, 1.5 mol / L, 2 mol / L, 2.5 mol / L, 3 mol / L, 3.5 mol / L, 4 mol / L, 4.5 mol / L, or 5 mol / L, preferably 2 mol / L to 4 mol / L. The concentration of the acidity regulator in the extraction solution meets the above conditions, providing an acidic environment for extraction and allowing niobium ions to form coordination anionic compounds with the anions of the acidity regulator, thereby being extracted and separated by the extractant. Simultaneously, it ensures that the content of coordination anionic compounds formed by hafnium in the acidic environment is extremely low, effectively improving the separation effect of hafnium and niobium.

[0014] According to embodiments of this application, the concentration of niobium in the extraction solution is 1 ppm to 100 ppm. In some embodiments, the concentration of niobium in the extraction solution is 1 ppm, 2 ppm, 5 ppm, 10 ppm, 15 ppm, 20 ppm, 25 ppm, 50 ppm, 75 ppm, or 100 ppm. Meeting the above conditions in the concentration of niobium in the extraction solution can effectively improve the separation effect of hafnium and niobium.

[0015] According to embodiments of this application, the extractant includes at least one of primary amine extractants, tertiary amine extractants, methyltrioctylammonium chloride, and tri-n-octylamine; the primary amine extractant is preferably N1923, which is a mixture of straight-chain primary amines with 19 to 23 carbon atoms; the tertiary amine extractant is preferably N235, which is a mixture of branched trialkylamines with 8 to 10 carbon atoms. By using at least one of the extractants, the coordinated anionic compound formed by the coordination of niobium ions with the anion of the acidity regulator is extracted, thereby achieving the collection and separation of niobium in the extractant while the retention of hafnium in the raffinate aqueous phase, which is beneficial to improving the separation effect of hafnium and niobium.

[0016] According to embodiments of this application, the extractant is pre-diluted. In some embodiments, the dilution is achieved by mixing the extractant with kerosene, and the concentration of the extractant after dilution is 0.01 mol / L to 1 mol / L. In some embodiments, the concentration of the extractant after dilution is 0.01 mol / L, 0.02 mol / L, 0.05 mol / L, 0.1 mol / L, 0.15 mol / L, 0.2 mol / L, 0.25 mol / L, 0.5 mol / L, 0.75 mol / L, or 1 mol / L, preferably 0.15 mol / L to 0.25 mol / L. The concentration of the extractant after dilution meeting the above conditions can effectively improve the separation effect of hafnium and niobium.

[0017] According to an embodiment of this application, the volume ratio of the extractant to the original extract solution in the extraction process is (1~2):1. This facilitates the complete dissolution of niobium in the original extract solution in the extractant, achieving effective separation of hafnium and niobium.

[0018] According to an embodiment of this application, the extraction process is carried out at a temperature of 25°C to 35°C and a stirring rate of 250 rpm to 350 rpm for 5 to 10 minutes. This facilitates sufficient contact between the two phases, resulting in uniform mass transfer, improving the selectivity of the extractant for niobium in the extraction solution, and effectively achieving the separation of hafnium and niobium.

[0019] According to an embodiment of this application, the separation process includes a settling process for 3 to 10 minutes. Thus, the settling process allows for the separation of the organic phase and the aqueous phase after extraction, facilitating the separation of hafnium and niobium.

[0020] Beneficial effects: The method for separating hafnium and niobium disclosed in this application can effectively separate the two substances. This separation method significantly improves the separation coefficient of hafnium and niobium, achieving more efficient separation. It can also effectively remove niobium while efficiently retaining hafnium in feed solutions with concentrations differing by 3000 times or more between high-concentration hafnium and low-concentration niobium, meeting the stringent requirements of high-end industries for high-purity hafnium products. The extractant used in this separation method has low toxicity, minimal environmental impact, and low preparation cost, which can improve the economic benefits and competitiveness of large-scale applications, possessing significant industrial application value and practical significance. Detailed Implementation

[0021] The present application will be explained below with reference to embodiments and comparative examples. Those skilled in the art will understand that the following embodiments and comparative examples are for illustrative purposes only and should not be construed as limiting the scope of the application. Where specific techniques or conditions are not specified in the embodiments and comparative examples, they are performed in accordance with the techniques or conditions described in the literature in the art or according to the product instructions. Unless otherwise stated, the active pharmaceutical ingredients, excipients, and reagents used in the following embodiments and comparative examples are commercially available products or can be prepared by known methods.

[0022] Before introducing the technical solution of this application, the relevant knowledge of this application will be introduced below: In the embodiments of this application, "extraction processing" can be simply referred to as extraction, also known as solvent extraction or liquid-liquid extraction. It is a separation and purification technology based on the difference in solubility of solute in two immiscible (or slightly soluble) solvents. The core is to selectively transfer the target substance from one liquid phase (original system) to another liquid phase (extraction phase) by selecting a suitable extraction solvent, and finally achieve the separation, concentration or purification of the target substance and impurities.

[0023] In the embodiments of this application, "primary amine extractant" refers to a mixed type of extractant of organic compounds whose molecular structure contains a -NH2 (amino) functional group and whose nitrogen atom is attached to a long-chain alkyl group and two hydrogen atoms.

[0024] In the embodiments of this application, "tertiary amine extractant" refers to a mixed type of extractant of organic compounds in which three alkyl groups are attached to the nitrogen atom in the molecular structure and there are no hydrogen atoms.

[0025] In the embodiments of this application, "coordination anion compound" refers to a negatively charged coordination unit formed by the central ion (or atom) and multiple coordination anions through coordination bonds, which is a special type of coordination compound (complex).

[0026] In the embodiments of this application, "mass transfer" refers to the process by which a substance is transferred from one phase (or one region) to another phase (or another region) under the driving force of concentration difference, temperature difference, pressure difference or chemical potential difference.

[0027] In the embodiments of this application, the "mixing and clarifying tank" refers to a type of step-by-step contact extraction equipment in the extraction industry. The core is composed of two functional units, a "mixing chamber" and a "clarification chamber," connected in series. Through the cyclical operation of "mixing (achieving mass transfer) - clarification (achieving phase separation)," the target substance is transferred from one phase to another.

[0028] In the embodiments of this application, "partition ratio" refers to a parameter that measures the distribution behavior of a target substance between two phases during extraction treatment. Specifically, it is the ratio of the total concentration of the target substance in the extraction phase (including free state and various bound state) to the total concentration in the raffinate phase (including free state and various bound state) when extraction equilibrium is reached. The larger the partition ratio, the more soluble the target substance is in the extraction phase, and the higher its extraction efficiency.

[0029] In the embodiments of this application, "recovery rate" refers to a parameter that quantifies the separation and extraction effect of the target substance in the extraction process. Specifically, it is the percentage of the total amount of the target substance remaining in the raffinate aqueous phase after extraction equilibrium compared with the total amount of the target substance in the initial system.

[0030] In the embodiments of this application, "residual aqueous phase" refers to the remaining aqueous phase system with water as solvent in the lower layer after the aqueous feed liquid and the organic phase have been in full contact and reached extraction equilibrium.

[0031] The technical solutions in the embodiments of this application will be described below with reference to the examples. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0032] Example 1 In this embodiment, hafnium and niobium are separated according to the following method: 1. Weigh 150g of hafnium chloride and slowly add it to 1 L of 3 mol / L nitric acid solution to dissolve it. Stir at 200 rpm in a mechanical stirrer at 28°C until completely dissolved.

[0033] 2. Add niobium nitrate solution to adjust the niobium concentration to 10 ppm to prepare the extraction stock solution.

[0034] 3. Weigh out the primary amine extractant N1923 and dissolve it in kerosene to prepare an extractant with an N1923 concentration of 0.2 mol / L.

[0035] 4. Add the original extract and the extractant to the mixing and clarifying tank at a volume ratio of 1:1, and perform extraction treatment for 10 min at a temperature of 30℃ and a stirring speed of 300 rpm.

[0036] 5. After extraction, allow the mixture to stand for 10 minutes, collect the raffinate, and analyze the concentrations of hafnium and niobium to evaluate the separation effect.

[0037] Examples 2-4 Hafnium and niobium were separated according to the method of Example 1, except that the extractant was replaced with N235, methyltrioctylammonium chloride, and tri-n-octylamine, respectively.

[0038] The separation effect of the obtained extractant is shown in Table 1: Table 1:

[0039] The results are shown in Table 1: The raffinate phase refers to the remaining aqueous phase system with water as the solvent, which is located in the lower layer after the aqueous feed solution and organic phase have fully contacted and reached extraction equilibrium. In the four examples of N1923, N235, methyltrioctylammonium chloride, and tri-n-octylamine, the hafnium recovery rate was 99.90% or higher, proving that the method provided in the embodiments of this application can achieve deep removal of low-concentration niobium from high-concentration hafnium feed solutions with concentration differences of 3000 times or more.

[0040] Comparative Example 1 Hafnium and niobium were separated according to the method of Example 1, except that the extractant N1923 in step 3 was replaced with tributyl phosphate (TBP).

[0041] The extraction and separation results are shown in Table 2: Table 2:

[0042] The results are shown in Table 2: When using TBP as an extractant, under the same extraction system conditions, TBP also has a strong extraction ability for hafnium, resulting in a large amount of hafnium entering the organic phase. The recovery rate of hafnium dropped to 68.50%, which is significantly different from the separation and recovery effect of the extractant provided in the embodiments of this application. It is impossible to achieve efficient separation of hafnium and niobium or deep removal of niobium.

[0043] Conclusion: The separation method of this application can achieve more efficient separation of hafnium and niobium, and can effectively achieve deep removal of niobium while efficiently retaining hafnium in feed solutions with concentration differences of 3000 times or more, thus meeting the stringent requirements of high-end industries for high-purity hafnium products.

[0044] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and such ranges or values ​​should be understood to include values ​​close to such ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0045] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0046] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A method for separating hafnium and niobium, characterized in that, include: The original extract is extracted in an extractant, the original extract comprising the hafnium-containing compound to be separated, the niobium to be separated, and an acidity regulator; as well as The extraction product is then separated to isolate the hafnium and niobium.

2. The method according to claim 1, characterized in that, The extract solution is obtained through the following method: The sample containing the hafnium-containing compound to be separated was dissolved in an acidity adjuster; and Optionally, the concentration of the dissolved product may be further adjusted.

3. The method according to claim 1, characterized in that, The acidity regulator includes at least one of nitric acid, hydrochloric acid, sulfuric acid, phosphoric acid, and perchloric acid.

4. The method according to claim 1, characterized in that, The hafnium-containing compound includes at least one of hafnium dioxide, hafnium chloride, and industrial-grade hafnium-containing liquid.

5. The method according to claim 2, characterized in that, The dissolution process was carried out at a stirring rate of 150 rpm to 200 rpm and a stirring temperature of 20°C to 30°C.

6. The method according to claim 2, characterized in that, After dissolution treatment, the concentration of hafnium ranges from 1000 ppm to 300000 ppm. The concentration of nitric acid is 0.5 mol / L to 5 mol / L, preferably 2 mol / L to 4 mol / L; The concentration of niobium ranges from 1 ppm to 100 ppm.

7. The method according to claim 1, characterized in that, The extractant includes at least one of primary amine extractants, tertiary amine extractants, methyltrioctylammonium chloride, and tri-n-octylamine; Preferably, the primary amine extractant is N1923, which is a mixture of straight-chain primary amines with 19 to 23 carbon atoms; Preferably, the tertiary amine extractant is N235, which is a mixture of branched trialkylamines with 8 to 10 carbon atoms.

8. The method according to claim 1, characterized in that, The extractant has been pre-diluted; Optionally, the dilution process is achieved by mixing the extractant with kerosene, wherein the concentration of the extractant after dilution is 0.01 mol / L to 1 mol / L; Preferably, the concentration of the extractant after dilution is 0.15 mol / L to 0.25 mol / L.

9. The method according to claim 1 or 7, characterized in that, In the extraction process, the volume ratio of the extractant to the original extract solution is (1~2):

1.

10. The method according to claim 1, characterized in that, The extraction process was carried out at a temperature of 25℃~35℃ and a stirring rate of 250 rpm~350 rpm for 5 min~10 min.

11. The method according to claim 1, characterized in that, The separation process includes a settling process, which takes 5 to 10 minutes.

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