Method for deeply removing antimony and tantalum from niobium-containing solution

Abstract

The invention discloses a method for deeply removing antimony and tantalum from a niobium-containing solution, and belongs to the technical field of rare metal purification. According to the method, the niobium solution containing antimony, tantalum and fluorine is subjected to oxidative complexing through inorganic peroxide, then acid adjustment and extraction impurity removal are conducted, the niobium-containing purified liquid is obtained, the method can achieve deep removal of trace impurities antimony and tantalum in the niobium solution, the high-purity clean niobium solution is obtained, and a 4N-grade high-purity niobium oxide product is easy to obtain. Compared with a previous niobium impurity removal process, the method has the advantages of being short in technological process, easy to operate, low in reagent cost, free of pollution, high in impurity removal efficiency, good in product quality and the like, and has industrial application value.

Description

Technical Field

[0001] The present invention relates to a method for removing impurities from a niobium-containing solution, in particular to a method for deeply removing antimony and tantalum from a niobium-containing solution, and specifically to a method for deeply removing antimony and tantalum impurities from a stripping section niobium solution produced in a tantalum-niobium metallurgical process, belonging to the technical field of rare metal purification. Background Art

[0002] Niobium is widely used in electronics, chemical industry, aerospace, superconductivity, optics, medical and other fields due to its high melting point, corrosion resistance, deformation resistance and good thermal conductivity. Niobium pentoxide (hereinafter referred to as niobium oxide, Nb2O5) is an important raw material for the production of metallic niobium, and is also the basic raw material for pulling nickel niobate single crystals, making special optical glass, high-frequency and low-frequency capacitors and piezoelectric ceramic components, catalysts, etc. For example, niobium oxide is added to glass lenses to make them lighter and thinner, and show stronger elasticity, so that digital cameras and mirrorless system cameras have better performance and smaller components; niobium oxide provides precise frequency control, optimized selectivity and reduced distortion for surface acoustic wave filters (SAW) used in mobile devices such as smartphones, tablets, laptops or satellite positioning applications; spherical niobium oxide is used as a dopant for spray powder, multilayer ceramic capacitors (MLCC) barium titanate dielectrics / potassium sodium niobate (KNN) lead-free piezoelectric materials, and sputtering targets for the production of display coatings. With the vigorous development of industries such as 5G, new energy vehicles, high-end electronic equipment, and aerospace, more and more industries have put forward higher requirements for the purity of niobium oxide, and the demand for material purity has also promoted the continuous development of high-purity material preparation technology. According to different usage requirements and chemical compositions, the non-ferrous metal industry standard YS / T548-2007 divides niobium oxide products into four grades: FNb2O5-048, FNb2O5-045, FNb2O5-04, and FNb2O5-035. Among them, the tantalum (Ta) impurity content (mass fraction) is required to be no more than 0.0003%, 0.0005%, 0.001%, and 0.002%, respectively, and the antimony (Sb) is required to be no more than 0.0002%, 0.0006%, and 0.001%. Overall, the content of impurities such as Ta and Sb (except fluorine, silicon, etc.) is the key consideration for niobium oxide products, and is also the key to restricting the grade of niobium oxide products.

[0003] A Chinese patent (publication number: CN102358918A) discloses a method for removing antimony from ultra-high purity tantalum pentoxide and niobium pentoxide, by using D296 resin to adsorb tantalum and D290 resin to adsorb niobium in the reverse tantalum solution and reverse niobium solution of the secondary octanol system, respectively, to achieve the purpose of removing antimony from tantalum and niobium solutions. A Chinese patent (publication number: CN103408070A) discloses a process for removing antimony from niobium tantalite to prepare high-purity niobium oxide, firstly leaching niobium tantalite with 36% hydrochloric acid to remove most of the antimony, then decomposing tantalum and niobium with sulfuric acid and hydrofluoric acid, and adding hydrazine solution to reduce the high-valent antimony in the leaching solution, and finally obtaining high-purity niobium oxide through "secondary octanol extraction-reverse niobium-neutralization-roasting". A Chinese patent (publication number: CN104445406A) discloses a method for preparing ultra-high purity niobium oxide, using fluoroniobic acid solution as raw material, adjusting the acidity, extracting with octanol, acid washing and stripping to obtain ultra-high purity fluoroniobic acid solution, adding liquid ammonia for sedimentation and washing with hot ammonia water at 60~70℃ to obtain niobium hydroxide filter cake, and finally calcining in steps to obtain ultra-high purity niobium oxide product. A Chinese patent (publication number: CN104477993A) discloses a production method for preparing high purity niobium oxide using high antimony niobium liquid, adding saturated ammonium sulfate solution to high antimony niobium liquid, controlling the niobium concentration of the solution to ≥70g / L, the acidity to ≥3N, and then extracting and stripping the acid-adjusted niobium liquid with octanol to prepare pure niobium liquid, and then neutralizing and precipitating, calcining at 900~1000℃ to prepare high purity niobium oxide. A Chinese patent (publication number: CN108862384B) discloses a method for preparing low-antimony niobium oxide / tantalum oxide, wherein the antimony in the solution is first reduced to a low-valent state of +3 using a carboxylic acid reducing agent, triethanolamine or sulfide ethanolamine complexing agent is added to generate a stable antimony complex, and then alkali is added for neutralization, washing, drying, and calcination to achieve efficient separation of niobium products or tantalum products from antimony. Similarly, a Chinese patent (publication number: CN 109097572A) discloses the separation of TaSb and NbSb by adding a water-soluble antimony complexing agent to a fluoroniobic acid / fluorotantalate aqueous solution, neutralizing and precipitating with ammonia, washing and filtering. A Chinese patent (publication number: CN118389834A) discloses a method for deep purification of tantalum-niobium metallurgical solution, which captures difficult-to-separate impurities under medium acidity conditions through oxidation-acid adjustment-foam impurity removal, and then separates the target metal under high acidity through acid adjustment and niobium extraction, and finally obtains a clean reverse niobium solution. In general, the existing technical route has cumbersome processes and complex operation procedures. It mainly obtains pure niobium liquid by repeatedly extracting / adsorbing the main element niobium. However, the concentration of niobium liquid in the metallurgical process can generally reach 60~90g / L. The re-extraction process will cause a large amount of organic phase / adsorption resin consumption, increase energy consumption, and low impurity removal efficiency. Some patented technologies also require the consumption of additional expensive reducing agents, chelating agents and foam stabilizers, which are difficult to recycle and reuse, which not only greatly increases the cost of impurity removal, but also easily causes pollution and seriously affects product quality. Summary of the invention

[0004] In order to solve the technical problems of the existing technology that it is difficult to separate and remove impurities such as antimony and tantalum from niobium-containing solutions and the high separation cost, the purpose of the present invention is to propose a method for deep removal of antimony and tantalum from niobium-containing solutions. The method can improve the removal efficiency of antimony and tantalum, shorten the separation process, reduce costs and pollution, and is conducive to the subsequent acquisition of high-purity niobium pentoxide.

[0005] In order to achieve the above technical objectives, the present invention provides a method for deep removal of antimony and tantalum from a niobium-containing solution. The method comprises the following steps: firstly subjecting the niobium solution containing antimony, tantalum and fluorine to oxidative complexation with an inorganic peroxide, and then subjecting the solution to acid adjustment and extraction for impurity removal to obtain a niobium-containing purified solution.

[0006] The key to the technical solution of the present invention is to use inorganic peroxides to perform oxidative complexation treatment on the niobium solution containing antimony, tantalum and fluorine, and use peroxide ions to convert NbOF5 in the niobium solution into 2- Selective conversion of niobium in ionic form into Nb(O2)F5 2- (pH≤1), Nb(O2)2F4 3- (1≤pH≤5) ions, which are difficult to be extracted by conventional oxygen-containing extractants, while tantalum and antimony in niobium solution mainly exist in the form of fluorine complex anions that are easily extracted by conventional oxygen-containing extractants, which is conducive to the extraction and separation of antimony, tantalum and niobium. More specifically, due to TaF7 2- 、TaF6 - 、SbF7 2- 、SbF6 - There are differences in properties such as ion size and charge-to-mass ratio between the oxygen-containing extractant and the fluorine complex ions of tantalum and antimony, which makes the affinity of the oxygen-containing extractant to the fluorine complex ions of tantalum and antimony greater than that of the fluorine complex ions of niobium. The existing technology mainly uses this feature to use oxygen-containing extractants to achieve the extraction and separation of tantalum and antimony from niobium solutions, but the existing oxygen-containing extractants still cannot achieve the deep separation of tantalum and antimony in niobium solutions. The key to the present invention is to use inorganic peroxides to convert niobium fluorine oxygen complex anions into niobium fluorine peroxy complex anions, and the extraction ability of oxygen-containing extractants for niobium fluorine peroxy complex anions is lower than that of niobium fluorine oxygen complex anions, thereby further widening the extraction and separation ability of oxygen-containing extractants for tantalum, antimony and niobium, and improving the extraction and separation effect of tantalum, antimony and niobium. At the same time, based on the possible valences of antimony in general tantalum-niobium concentrates, there are +3 valences and +5 valences. The added peroxide ions can oxidize +3 valence antimony to +5 valences to a certain extent, and the fluorine complex anions of +5 valence antimony are easier to be extracted than +3 valence antimony, resulting in a further increase in the extraction rate of antimony. In summary, the present invention changes the existing form of niobium ions in the niobium solution through an oxidation complex reaction, which is more conducive to the extraction and separation of tantalum, antimony and niobium.

[0007] As a preferred solution, the concentration of Nb in the niobium solution is 60-70 g / L, the concentration of Sb is 0.01-0.12 g / L, the concentration of Ta is 0.2-0.4 g / L, the concentration of hydrogen ions is 1-6 mol / L, and the concentration of fluoride ions is 1-4 mol / L. The niobium solution of the present invention is specifically a niobium solution produced in the stripping section of the tantalum-niobium metallurgical production process. Under acidic conditions and the presence of fluoride ions, the main forms of niobium, tantalum, and antimony in the niobium solution are NbOF5 2- 、TaF7 2- 、TaF6 - 、SbF7 2- 、SbF6 - It is generally believed that the extraction process of tantalum and niobium is a "pseudo" salt extraction. Regardless of whether it is a ketone, alcohol, amide, phosphine oxide, or phosphonate extractant, they are all oxygen-containing extractants. This type of oxygen-containing extractant can attract positively charged hydrogen ions or hydronium ions to form "pseudo" cations, and then combine with tantalum, niobium, antimony and other complex anions in the aqueous phase by electrostatic attraction to form "pseudo" salts, thereby achieving extraction. When peroxide ions are introduced into the niobium solution, the niobium oxygen-fluoride complex anions are selectively converted into niobium fluoride peroxy complex anions that are more difficult to be extracted by oxygen-containing extractants, such as Nb(O2)F5 2- (pH≤1), Nb(O2)2F4 3- (1≤pH≤5) plasma, which is more conducive to the extraction and separation of niobium, tantalum and antimony.

[0008] As a preferred solution, the inorganic peroxide includes at least one of hydrogen peroxide, sodium peroxide, and barium peroxide. The preferred inorganic peroxide can mainly provide peroxide ions in the solution system to achieve the reaction of NbOF5 2- The oxidative complexation of ions forms Nb(O2)F5 which is more difficult to be extracted by oxygen-containing extractants. 2- 、Nb(O2)2F4 3- Plasma. A further preferred inorganic peroxide is hydrogen peroxide, which can avoid the introduction of impurity metal ions. At the same time, under acidic conditions, these inorganic peroxides show oxidizing properties and can oxidize trivalent antimony, thereby improving the extraction efficiency of oxygen-containing extractants for antimony.

[0009] As a preferred solution, the amount of the inorganic peroxide added to the niobium solution is 2-20 g / L. The amount of the inorganic peroxide added to the niobium solution is further preferably 10-16 g / L. If the amount of the inorganic peroxide added is too low, it will be difficult to completely convert the niobium fluoride oxygen complex anion into the niobium fluoride peroxy complex anion.

[0010] As a preferred solution, the oxidation complexation conditions are: temperature of 5-40° C. and time of 0.5-2 h. Under the preferred oxidation complexation conditions, the niobium fluoride oxyanion can be fully converted into niobium fluoride peroxyanion.

[0011] As a preferred solution, the acid adjustment reagent used in the acid adjustment process includes at least one of hydrofluoric acid, sulfuric acid, nitric acid and hydrochloric acid. As a preferred solution, the acid concentration of the solution system is adjusted to 6-10 mol / L during the acid adjustment process. The acid adjustment reagent is further preferably a combination of sulfuric acid and hydrofluoric acid. During the acid adjustment process, the sulfuric acid concentration in the solution system is adjusted to 1-6 mol / L, and the hydrofluoric acid concentration is between 1-6 mol / L. The sulfuric acid concentration is further preferably 4-6 mol / L, and the hydrofluoric acid concentration is further preferably 3-5 mol / L. The preferred acid system is conducive to the extraction and separation of fluorine complex anions of tantalum and antimony by oxygen-containing extractants.

[0012] As a preferred solution, the extractant used in the extraction process includes at least one of ketone extractants, alcohol extractants, amide extractants, phosphine oxide extractants, and phosphonate extractants. As a more preferred solution, the ketone extractant includes at least one of methyl isobutyl ketone and methyl isopropyl ketone. As a more preferred solution, the alcohol extractant includes at least one of sec-octanol, isooctyl alcohol, and amyl alcohol. As a more preferred solution, the amide extractant includes at least one of N,N-dimethylheptyl acetamide, N,N-di-n-mixed acetamide, and N-phenyl-N-octyl acetamide. As a more preferred solution, the phosphine oxide extractant includes at least one of tributyl phosphine oxide, trioctyl phosphine oxide, and trialkyl phosphine oxide. As a preferred solution, the phosphonate extractant includes at least one of tributyl phosphate, trioctyl phosphate, and dibutyl butyl phosphonate. The preferred extractants are all conventional extractants for extracting tantalum and antimony in fluorine-containing solution systems.

[0013] As a preferred solution, the extraction process adopts a multi-stage extraction method, the extraction stage is 1 to 7, the volume proportion of the extractant in the extracted organic phase is not less than 20%, the O / W phase volume ratio is 1.3 to 0.95:1, the extraction temperature is 0 to 40°C, and the extraction time is 5 to 10 minutes. The extraction stage is more preferably 3 to 6.

[0014] As a preferred solution, the extraction organic phase contains a diluent; the diluent includes at least one of sulfonated kerosene, 260# solvent oil, paraffin oil, and n-octane; the volume proportion of the diluent in the extraction organic phase is less than 20%.

[0015] The niobium-containing solution of the present invention is subjected to deep antimony and tantalum removal to obtain a high-purity niobium-containing purification solution, and then conventional neutralization precipitation and roasting are carried out to prepare a high-purity niobium oxide product. Preferably, the alkaline solution reagent used for neutralization precipitation includes at least one of sodium hydroxide, potassium hydroxide, and ammonia water, and ammonia water is further preferred. The pH value of neutralization precipitation is controlled between 7 and 11, and further preferably 8 < pH < 9. Preferably, the roasting temperature is controlled between 700 and 1000 °C, the further preferred roasting temperature is 850 °C, and the roasting time is preferably 4 to 6 h, and further preferably 5 h.

[0016] Compared with the prior art, the technical solution of the present invention has the following obvious technical advantages:

[0017] (1) The present invention can achieve deep removal of antimony and tantalum in the niobium solution, and the obtained clean niobium solution can be used to prepare a 4N-grade high-purity niobium oxide product.

[0018] (2) Before extraction and impurity removal, the present invention does not need to add special reagents such as hydrazine, triethanolamine or sulfhydrylethanolamine, antimony organic complexing agent, and foam stabilizer, only consuming some peroxide ions, with low cost and good operating environment, which is beneficial to improving product quality.

[0019] (3) In the extraction and impurity removal process of the present invention, mainly impurities antimony and tantalum in the niobium solution are extracted, with high separation efficiency, less extractant consumption and small equipment investment; compared with the ion exchange method, the mass transfer rate in the extraction process is fast, reducing the discharge of wastewater, which is beneficial to environmental protection.

[0020] (4) The extraction and separation process flow of the present invention is short, easy to realize continuous operation, and easy to realize industrialization. Brief Description of the Drawings

[0021] Figure 1 It is a process flow chart for deep antimony and tantalum removal in the niobium-containing solution of the present invention and the preparation of high-purity niobium oxide. Detailed Embodiments

[0022] The following specifically illustrates the content of the present invention through examples. It should be noted that these examples are only for better understanding the content of the present invention rather than further limiting the protection scope of the present invention.

[0023] The following examples adopt Figure 1 the described process flow chart for implementation.

[0024] Example 1

[0025] First, 1.2 times the theoretical amount of hydrogen peroxide was added to the niobium acid solution (Nb 68.20g / L, Ta3.02mg / L, Sb 4.15mg / L, hydrogen ion concentration 5.60mol / L, fluorine ion concentration 2.02mol / L) containing tantalum and antimony impurities in the stripping section provided by a tantalum and niobium smelter for oxidation / complexation, and the total amount added was 16.74g / L; then the niobium solution was acidified by a combination of sulfuric acid and hydrofluoric acid solutions, and the sulfuric acid concentration of the solution was controlled to be 4.62mol / L, and the hydrofluoric acid concentration was controlled to be 4.52 mol / L. Then, a mixed extraction system of tributyl phosphate and octanol (the volume fraction of the extractant component was 80%) was selected and the acidified extracted niobium solution was placed in a separating funnel according to the volume ratio of organic phase / aqueous phase of 1:1 for 5-stage countercurrent extraction. The oscillation time was controlled at 10min to obtain a clean residual niobium solution after tantalum and antimony removal, with an antimony removal rate of 94%, a tantalum removal rate of up to 98%, and a niobium loss rate of about 5%. Subsequently, ammonia water was slowly added to the clean niobium liquid with continuous stirring to control the pH value of the precipitation endpoint at about 8.5. When a large amount of white solid was precipitated, it was filtered and vacuum dried. The completely dried niobium solid was oxidized and roasted at a temperature of 850°C for 6 hours to obtain a high-purity niobium oxide product. The antimony content in the niobium oxide was less than 3ppm, and the tantalum content was less than 2ppm, meeting the requirements of 4N grade high-purity niobium oxide products.

[0026] Example 2

[0027] To the niobium acid solution (Nb 68.20g / L, Ta 3.02mg / L, Sb 4.15mg / L, hydrogen ion concentration 5.60mol / L, fluoride ion concentration 2.02mol / L) containing tantalum and antimony impurities in the stripping section provided to a tantalum-niobium smelter was added 1.05 times the theoretical amount of hydrogen peroxide for oxidation / complexation, and the total amount added was 14.65g / L; then, the niobium solution was acidified using a combination of sulfuric acid and hydrofluoric acid solutions, and the concentrations of sulfuric acid and hydrofluoric acid in the solution were controlled to be 4.01mol / L and 4.42mol / L respectively. Then, the methyl isobutyl ketone (MIBK) extraction system (the volume fraction of the extractant component is 100%) and the acid-adjusted extracted niobium liquid are placed in a separatory funnel according to the volume ratio of the organic phase / aqueous phase of 0.95:1.0, and mixed for 5-stage countercurrent extraction. The oscillation time is controlled at 10 minutes to obtain a clean residual niobium liquid after tantalum and antimony removal. The antimony removal rate is 92%, the tantalum removal rate is 96.7%, and the niobium loss rate is about 6.5%. Then, ammonia water is slowly added to the clean niobium liquid, and it is stirred continuously to control the precipitation end point pH value at about 9.0. When a large amount of white solid is precipitated, it is filtered and vacuum dried; the completely dried niobium solid is oxidized and roasted at a roasting temperature of 850°C and a controlled roasting time of 6 hours to obtain a high-purity niobium oxide product. After testing, the antimony content in the niobium oxide is less than 2.5ppm, and the tantalum content is less than 2ppm, which meets the requirements of 4N grade high-purity niobium oxide products.

[0028] Example 3

[0029] Similarly, the niobium acid solution containing tantalum and antimony impurities of Example 1 (Nb 68.20 g / L, Ta 3.02 mg / L, Sb 4.15 mg / L, hydrogen ion concentration 5.60 mol / L, fluoride ion concentration 2.02 mol / L) was selected, and 1.2 times the theoretical amount of hydrogen peroxide was added for oxidation / complexation, and the total amount added was 16.74 g / L; then, a combination of sulfuric acid and hydrofluoric acid solutions was used to adjust the acidity of the niobium solution, and the concentration of sulfuric acid in the solution was controlled to be 4.62 mol / L, and the concentration of hydrofluoric acid in the solution was controlled to be 4.52 mol / L. Then, a mixed extraction system of N,N-dimethylheptyl acetamide and 2-octanol (the volume fraction of the extractant component is 60%) was selected and the acid-adjusted extracted niobium solution was placed in a separatory funnel according to the volume ratio of organic phase / aqueous phase of 1.05:1.0 for 5-stage countercurrent extraction. The oscillation time was controlled at 10 minutes to obtain a clean residual niobium solution after tantalum and antimony removal. The antimony removal rate was 93%, the tantalum removal rate was 98.5%, and the niobium loss rate was about 7.1%. Then, ammonia water was slowly added to the clean niobium solution, and it was stirred continuously to control the precipitation end point pH value at about 8.5. When a large amount of white solid was precipitated, it was filtered and vacuum dried; the completely dried niobium solid was oxidized and roasted at a roasting temperature of 850°C and a controlled roasting time of 6 hours to obtain a high-purity niobium oxide product. After testing, the antimony content in the niobium oxide was less than 2.5ppm, and the tantalum content was less than 2ppm, which met the requirements of 4N grade high-purity niobium oxide products.

[0030] Example 4

[0031] A niobate solution (Nb 28g / L) containing 1.2g / L Ta impurities and 20mg / L Sb was prepared, the sulfuric acid concentration was controlled to be about 6.0mol / L, the fluoride ion concentration was about 5.5mol / L, and 1.2 times the theoretical amount of hydrogen peroxide was added for oxidation / complexation, with a total amount of 6.87g / L; then a mixed extraction system of tributyl phosphate and octanol (the volume fraction of the extractant component was 80%) was selected and the acid-adjusted extracted niobium solution was placed in a separatory funnel at a volume ratio of 1:1 between the organic phase and the aqueous phase, and a 7-stage countercurrent extraction was performed, and the oscillation time was controlled at 10min to obtain clean residual niobium after tantalum and antimony were removed. The antimony impurity removal rate is 91%, the tantalum removal rate is 98.5%, and the niobium loss rate is about 6.8%. Subsequently, ammonia water is slowly added to the clean niobium liquid with continuous stirring to control the pH value of the precipitation endpoint to be about 9.0. When a large amount of white solid is precipitated, it is filtered and vacuum dried. The completely dried niobium solid is oxidized and roasted at a temperature of 850°C for 5 hours to obtain a high-purity niobium oxide product. The antimony content in the niobium oxide is less than 3ppm, and the tantalum content is less than 3ppm, which also meets the requirements of 4N grade high-purity niobium oxide products.

[0032] Example 5

[0033] Prepare a niobate solution containing 1.2 g / L Ta impurities and 20 mg / L Sb (Nb 28 g / L), control the sulfuric acid concentration to about 6.0 mol / L, the fluoride ion concentration to about 5.5 mol / L, and add 1.2 times the theoretical amount of hydrogen peroxide for oxidation / complexation, with a total amount of 6.87 g / L; then select a single tributyl phosphate (TBP) extraction system (the volume fraction of the extractant component is 80%) and put it into a separatory funnel with the acid-adjusted niobium solution according to the volume ratio of organic phase / aqueous phase of 1.1:1, mix and perform 7-stage countercurrent extraction, and control the oscillation time to 10 minutes to obtain a clean extract after removing tantalum and antimony. The niobium liquid has an antimony impurity removal rate of 91.7%, a tantalum removal rate of 98.7%, and a niobium loss rate of about 8.0%. Subsequently, ammonia water is slowly added to the clean niobium liquid with continuous stirring to control the pH value of the precipitation endpoint at about 9.0. When a large amount of white solid is precipitated, it is filtered and vacuum dried. The completely dried niobium solid is oxidized and roasted at a temperature of 850°C for 5 hours to obtain a high-purity niobium oxide product. The antimony content in the niobium oxide is less than 3ppm, and the tantalum content is less than 3ppm, which also meets the requirements of 4N grade high-purity niobium oxide products.

[0034] Comparative Example 1

[0035] The only difference from Example 3 is that the niobium solution is directly acidified without adding hydrogen peroxide. Other operations and conditions are the same as those in Example 3.

[0036] The final measured results showed that the antimony removal rate in the solution after extraction equilibrium was 83%, the tantalum removal rate was 92%, but the niobium loss rate reached 18.8%.

[0037] Comparative Example 2

[0038] The only difference from Example 1 is that the niobium solution is directly acidified without adding hydrogen peroxide. Other operations and conditions are the same as those in Example 1.

[0039] The final measured results showed that after extraction equilibrium, the antimony removal rate in the solution was 80%, the tantalum removal rate was 92.1%, but the niobium loss rate was as high as 24.9%.

Claims

1. A method for deep removal of antimony and tantalum from a niobium-containing solution, characterized in that: The niobium solution containing antimony, tantalum and fluorine is firstly subjected to oxidation complexation with inorganic peroxide, and then subjected to acid adjustment and extraction to remove impurities, so as to obtain a purified solution containing niobium.

2. A method for deep removal of antimony and tantalum from a niobium-containing solution according to claim 1, characterized in that: The niobium solution has a Nb concentration of 60-70 g / L, a Sb concentration of 0.01-0.12 g / L, a Ta concentration of 0.2-0.4 g / L, a hydrogen ion concentration of 1-6 mol / L, and a fluoride ion concentration of 1-4 mol / L.

3. The method for deep removal of antimony and tantalum from a niobium-containing solution according to claim 1, characterized in that: The inorganic peroxide includes at least one of hydrogen peroxide, sodium peroxide and barium peroxide.

4. A method for deep removal of antimony and tantalum from a niobium-containing solution according to any one of claims 1 to 3, characterized in that: The amount of the inorganic peroxide added to the niobium solution is 2-20 g / L.

5. The method for deep removal of antimony and tantalum from a niobium-containing solution according to claim 1, characterized in that: The conditions of the oxidation complexation are: temperature of 5-40° C., and oxidation complexation time of 0.5-2 h.

6. The method for deep removal of antimony and tantalum from a niobium-containing solution according to claim 1, characterized in that: The acid adjustment reagent used in the acid adjustment process includes at least one of hydrofluoric acid, sulfuric acid, nitric acid and hydrochloric acid; During the acid adjustment process, the acid concentration of the solution system is adjusted to 6-10 mol / L.

7. The method for deep removal of antimony and tantalum from a niobium-containing solution according to claim 1, characterized in that: The extractant used in the extraction process includes at least one of a ketone extractant, an alcohol extractant, an amide extractant, a phosphine oxide extractant, and a phosphonate extractant; The ketone extractant includes at least one of methyl isobutyl ketone and methyl isopropyl ketone; The alcohol extractant includes at least one of sec-octanol, isooctyl alcohol and amyl alcohol; The amide extractant includes at least one of N,N-dimethylheptyl acetamide, N,N-di-n-mixed acetamide, and N-phenyl-N-octyl acetamide; The phosphine oxide extractant includes at least one of tributylphosphine oxide, trioctylphosphine oxide and trialkylphosphine oxide; The phosphonate extractant includes at least one of tributyl phosphate, trioctyl phosphate and dibutyl butylphosphonate.

8. The method for deep removal of antimony and tantalum from a niobium-containing solution according to claim 1 or 7, characterized in that: The extraction process adopts a multi-stage extraction method, the extraction stage is 1 to 7, the volume proportion of the extractant in the extracted organic phase is not less than 20%, the O / W phase volume ratio is 1.3 to 0.95:1, the extraction temperature is 0 to 40°C, and the extraction time is 5 to 10 minutes.

9. The method for deep removal of antimony and tantalum from a niobium-containing solution according to claim 8, characterized in that: The extraction organic phase contains a diluent; the diluent includes at least one of sulfonated kerosene, 260# solvent oil, paraffin oil, and n-octane; the volume proportion of the diluent in the extraction organic phase is less than 20%.

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