A method for purifying tantalum-niobium liquid based on flotation extraction

Abstract

This invention discloses a method for purifying tantalum-niobium solution based on flotation extraction. The method targets the tantalum-niobium-rich organic phase obtained from tantalum-niobium decomposition solution through conventional slurry extraction and acid washing back-extraction. Niobium is back-extracted using low-concentration acid to obtain a solution containing high-concentration niobium and low-concentration tantalum. This high-concentration niobium and low-concentration tantalum solution is then selectively extracted for tantalum using flotation extraction. The low-concentration tantalum-niobium-rich organic phase is returned to the tantalum-niobium-rich organic phase in the process for the next step. The high-concentration niobium solution is purified by flotation to obtain a clean, pure niobium solution. Simultaneously, the niobium-removed organic phase undergoes an anti-tantalum operation to obtain a high-concentration tantalum solution, which is then removed by flotation purification to obtain a clean tantalum solution. The obtained clean, pure niobium solution and tantalum solution are processed to ultimately obtain high-purity tantalum and high-purity niobium products, respectively. This method effectively overcomes the problems of traditional solvent extraction processes, such as lengthy processes, numerous cascade extraction stages, high equipment investment, and significant extractant loss.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of hydrometallurgy, and particularly to a method for purifying tantalum and niobium liquid based on floating extraction BACKGROUND

[0002] Tantalum and niobium are high-melting-point rare metals, which have characteristics such as high melting point, good plasticity, and stable chemical properties, and are widely used in fields such as hard alloy, aerospace, atomic energy, electronics, and energy materials. Because tantalum and niobium have similar atomic structures, they often coexist in nature, and have similar physical and chemical properties, which makes it difficult to separate tantalum and niobium. At present, the commonly used methods for separating and extracting tantalum and niobium in solution mainly include step-by-step crystallization, ion exchange, and solvent extraction.

[0003] In the method for separating and extracting tantalum and niobium, solvent extraction is realized according to the difference in distribution coefficient of metal ions between the aqueous phase and the organic phase, and has a series of advantages such as high production efficiency, high recovery rate, simple operation, and continuity. It has almost replaced other methods and has become one of the most important industrial methods for extracting and separating tantalum and niobium. The common extraction system is mainly HF-H2SO4-MIBK system and HF-H2SO4-2-octanol system. The tantalum and niobium concentrate is decomposed by hydrofluoric acid or mixed acid of hydrofluoric acid and sulfuric acid to obtain a decomposition liquid, and the tantalum and niobium are co-extracted by slurry extraction to obtain an organic phase, and after acid washing to remove impurities, the organic phase containing tantalum and niobium is stepwise back-extracted to realize the separation of tantalum and niobium. However, due to the long extraction process, multiple stages of extraction are usually required to strengthen mass transfer, so as to realize the deep separation of tantalum and niobium. The anti-niobium tantalum extraction section of the conventional solvent extraction method is often dozens or even hundreds of stages, which requires large equipment investment and causes serious loss of organic phase. The floating extraction method is a special gas floating separation technology, which realizes rapid mineralization of target components in aqueous solution by using emulsifying reagents, improves the solvent extraction process, increases the oil-water phase contact area with gas bubbles as the mass transfer carrier, and makes the oil-water phase fully contact, thereby improving the separation efficiency and enrichment multiple, and reducing the consumption of organic phase. In addition, the anti-tantalum liquid or anti-niobium liquid contains impurity elements such as silicon, iron, tungsten, copper, titanium, nickel, antimony, tin, and organic matter residues, which affects the preparation of high-purity tantalum and niobium products, and the impurity removal method is complicated and requires multiple purifications to meet market requirements.

[0004] The present application improves the traditional solvent extraction method based on floating extraction to separate and extract tantalum and niobium and prepare high-purity tantalum and niobium products. SUMMARY

[0005] In view of the problems of long process flow, multiple stages of cascade extraction, high equipment investment, and serious loss of extractant in the existing solvent extraction method for extracting tantalum and niobium, the purpose of the present application is to provide a method for purifying tantalum and niobium liquid based on floating extraction, which has the advantages of short process flow, few extraction stages, and low loss of organic phase, and finally realizes the separation and extraction of tantalum and niobium and the preparation of high-purity tantalum and niobium products.

[0006] To achieve the above technical purposes, the present application adopts the following technical solutions:

[0007] The tantalum-niobium decomposition solution is extracted by ore pulp, and the rich tantalum-niobium organic phase obtained by acid washing and back extraction is subjected to niobium back extraction to obtain a solution containing high-concentration niobium and low-concentration tantalum; the solution is subjected to selective extraction of tantalum by floating extraction, and the floating extraction method is to add a floating extraction agent, add a foam stabilizer, and introduce air to form micro-bubbles, so as to promote the hydrophobic mineralization of the bubbles to form fluorotantalate-flooding agent-bubble micro-droplets, which are lifted to the organic phase on the surface of the solution to obtain a high-concentration niobium solution and a low-concentration tantalum-niobium organic phase;

[0008] The low-concentration tantalum-niobium organic phase is returned to the rich tantalum-niobium organic phase in the process for the next operation;

[0009] The high-concentration niobium solution still contains impurity elements other than niobium and residual organic matter in water, which are removed by floating purification to obtain a clean pure niobium solution; at the same time, the organic phase after niobium back extraction is subjected to tantalum back extraction to obtain a high-concentration tantalum solution, and impurity elements other than tantalum and residual organic matter are removed by floating purification to obtain a clean tantalum solution. The clean tantalum solution and the clean niobium solution are treated by neutralization precipitation or salting-out method, and the obtained solid products are dried or calcined to obtain high-purity tantalum products and high-purity niobium products, respectively. The back extraction agent for niobium back extraction is at least one of sulfuric acid, hydrochloric acid, nitric acid, phosphoric acid and hydrofluoric acid, and the concentration of the back extraction agent is 0.1-4.5 mol / L, and the back extraction stage is less than 5.

[0010] In the present application, the rich tantalum-niobium organic phase obtained by conventional ore pulp extraction and acid washing back extraction of the tantalum-niobium decomposition solution is subjected to low-acid niobium back extraction to obtain a solution containing high-concentration niobium and low-concentration tantalum.

[0011] The key of the present application lies in the selection and concentration of the back extraction agent for niobium back extraction, so that most of the niobium and a small amount of tantalum are back extracted at the same time, ensuring high niobium back extraction rate and low tantalum back extraction rate, and the back extraction stage is small. On this basis, a floating extraction agent with high selectivity to specific metal ions or organic matter is selected, so that the metal ions form ion-flooding agent-bubble micro-droplets, and based on the floating extraction method, the metal ion-agent-bubble micro-droplet mass transfer and separation are strengthened by heterogeneous reaction and dynamic diffusion to purify and remove the tantalum from the high-concentration niobium and low-concentration tantalum solution, and the impurity elements and organic matter in the high-concentration tantalum solution and the high-concentration niobium solution are removed.

[0012] As a preferred solution, the stripping agent for stripping the tantalum- and niobium-rich organic phase is at least one of sulfuric acid, hydrochloric acid, nitric acid, phosphoric acid, and hydrofluoric acid, preferably sulfuric acid; the concentration of the stripping agent is 0.1-4 mol / L, preferably 0.25-1 mol / L, and more preferably 0.4-0.6 mol / L; and the stripping stage is 1-3 stages. In the technical solution of the present application, the type of the stripping agent is selected according to the actual production system, the concentration of the stripping agent is controlled, the niobium extraction rate is close to 100%, and a certain amount of tantalum is allowed to be stripped down, the tantalum extraction rate is controlled to be less than 10%, and the stripping stage is less than 3.

[0013] As a preferred solution, the floating extraction for selectively extracting tantalum from the high-concentration niobium and low-concentration tantalum solution comprises adding a floating extraction agent comprising at least one of ketones, amides, alcohols, and amines. 5～8 ) and N,N-dihybrid alkyl acetamide (CH3CONR2, R=C 7～9 H1 5～19 ) and at least one of trioctylmethylammonium chloride, trioctylamine, and secondary carbon primary amine; and at least one of secondary octanol, octanol-1, and pentanol, and simultaneously adding at least one of foam stabilizers sorbitan monooleate, sorbitan monooleate, polyacrylamide, alkyl trimethyl ammonium bromide (C 12～16 ), and sodium dodecyl sulfate; the molar ratio of the floating extraction agent to tantalum is 0.5-10, preferably 0.5-6, and more preferably 1.5-4.5; the addition amount of the foam stabilizer is 0.01-2 g / L, preferably 0.01-1 g / L, and more preferably 0.5-1 g / L; and the floating stage is 1-2 stages. Different floating extraction agent formulations can be selected for different solution systems to selectively extract tantalum from the high-concentration niobium and low-concentration tantalum solution, so that the tantalum concentration in the high-concentration niobium solution is less than 0.1 ppm, and the niobium extraction rate in the floating extraction process is less than 5%.

[0014] As a further preferred solution, the floating extraction agent for extracting tantalum from the high-concentration niobium and low-concentration tantalum solution comprises at least two of ketones, amides, alcohols, and amines. For example, the floating extraction agent comprises methyl isopropyl ketone and octanol-1, the floating extraction agent comprises trioctylmethylammonium chloride and secondary octanol, the floating extraction agent comprises acetoamide and cyclohexanone, and the like.

[0015] As a further preferred solution, the molar ratio of methyl isopropyl ketone to octanol-1 in the floating extraction agent used for extracting tantalum from the high-concentration niobium and low-concentration tantalum solution is 0.8-1.2:0.8-1.2.

[0016] As one of the further preferred schemes, when the solution with high concentration of niobium and low concentration of tantalum is subjected to the floatation extraction for tantalum, the molar ratio of trioctylmethylammonium chloride and sec-octanol in the floatation reagent used is 0.8-1.2:0.8-1.2.

[0017] As one of the further preferred schemes, when the solution with high concentration of niobium and low concentration of tantalum is subjected to the floatation extraction for tantalum, the molar ratio of trioctylmethylammonium chloride and sec-octanol in the floatation reagent used is 0.8-1.2:0.8-1.2.

[0018] Of course, for each floatation reagent, there is a certain proportion relationship between the floatation reagent and the tantalum in the solution with high concentration of niobium and low concentration of tantalum when the floatation reagent is used. For example, when the molar ratio of methyl isopropyl ketone and sec-octanol in the floatation reagent used is 0.8-1.2:0.8-1.2, the molar ratio of the floatation reagent to the tantalum in the solution is 1.8-2.2. When the molar ratio of trioctylmethylammonium chloride and sec-octanol in the floatation reagent used is 0.8-1.2:0.8-1.2, the molar ratio of the floatation reagent to the tantalum in the solution is 3.8-4.2. When the molar ratio of acetoamide and cyclohexanone in the floatation reagent used is 0.8-1.2:0.8-1.2, the molar ratio of the floatation reagent to the tantalum in the solution is 2.8-3.2.

[0019] As one of the further preferred schemes, when the solution with high concentration of niobium and low concentration of tantalum is subjected to the floatation extraction for tantalum, the molar ratio of trioctylmethylammonium chloride and sec-octanol in the floatation reagent used is 0.8-1.2:0.8-1.2.

[0020] The foam stabilizer is composed of sorbitan monooleate and cetyltrimethylammonium bromide in a molar ratio of 1-3.5:4.5.

[0021] The foam stabilizer is composed of polyacrylamide and sodium dodecyl sulfate in a molar ratio of 1-3.5:4.5.

[0022] As one of the further preferred schemes, when the solution with high concentration of niobium and low concentration of tantalum is subjected to the floatation extraction for tantalum, the molar ratio of trioctylmethylammonium chloride and sec-octanol in the floatation reagent used is 0.8-1.2:0.8-1.2. 12～16at least one of sodium dodecyl sulfate, sorbitan monooleate, sorbitan monooleate, polyacrylamide, the dosage of the floatation reagent is 0.1-10 g / L, the dosage of the foam stabilizer is 0.01-2 g / L, preferably 0.01-1 g / L, and the floatation stage is 1-2. The obtained high-concentration tantalum solution and high-concentration niobium solution contain impurity elements such as silicon, iron, tungsten, copper, titanium, nickel, antimony, tin and organic residues, and the combination of the floatation reagent and the foam stabilizer can completely remove the impurity elements and the organic residues.

[0023] As a further preferred solution, when the high-concentration niobium solution is subjected to floatation purification,

[0024] The first-stage floatation purification uses a phosphate ester as the floatation reagent and at least one of cetyltrimethylammonium bromide and sodium dodecyl sulfate as the foam stabilizer, wherein the dosage of the floatation reagent is 2-4 g / L and the dosage of the foam stabilizer is 0.1-0.2 g / L.

[0025] The second-stage floatation uses an alcohol and / or an amine as the floatation reagent and at least one of sorbitan monooleate, polyacrylamide and cetyltrimethylammonium bromide as the foam stabilizer, wherein the dosage of the floatation reagent is 1-4 g / L and the dosage of the foam stabilizer is 0.1-0.2 g / L.

[0026] As a further preferred solution, when the high-concentration niobium solution is subjected to floatation purification, the first-stage floatation purification uses at least one of di(2-ethylhexyl) phosphate ester and 2-ethylhexyl phosphate mono-2-ethylhexyl ester as the floatation reagent and at least one of cetyltrimethylammonium bromide and sodium dodecyl sulfate as the foam stabilizer.

[0027] In the second-stage floatation, at least one of sec-octanol, n-octanol and secondary carbon primary amine is used as the floatation reagent and at least one of sorbitan monooleate, polyacrylamide and cetyltrimethylammonium bromide is used as the foam stabilizer.

[0028] As a further preferred solution, when the high-concentration tantalum solution is subjected to floatation purification, the floatation reagent comprises an amine and the foam stabilizer comprises an alkyl trimethyl ammonium bromide, wherein the dosage of the floatation reagent is 0.5-1.5 g / L and the dosage of the foam stabilizer is 0.1-0.5 g / L.

[0029] As a further preferred solution, when the high-concentration tantalum solution is subjected to floatation purification, the floatation reagent comprises at least one of trioctylmethyl ammonium chloride and trioctyl amine, and the foam stabilizer comprises at least one of cetyltrimethylammonium bromide and dodecyl trimethyl ammonium bromide.

[0030] The solid precipitate produced by neutralization and precipitation or salting-out method using the clean tantalum liquid and the clean niobium liquid is dried or calcined to obtain high-purity tantalum product and high-purity niobium product, respectively. The high-purity tantalum product refers to a product with a purity greater than 99.995%, and the purity of the product after optimization can be greater than or equal to 5N. The high-purity niobium product refers to a product with a purity greater than or equal to 99.99%.

[0031] Compared with the prior art, the technical scheme of the present application has the beneficial effects that:

[0032] The present application uses the advantages of floating extraction technology. First, the rich tantalum and niobium organic phase obtained by conventional ore pulp extraction and acid washing stripping is stripped. The stripping step in the conventional process separates tantalum and niobium, which requires dozens or even hundreds of different stages. In this method, most of the niobium and a small amount of tantalum are stripped at the same time, and the stripping stage number is less. Then, the small amount of tantalum in the solution is completely purified and removed by floating extraction. At the same time, due to the requirements of high-purity tantalum and niobium products on the content of impurity elements and the residual amount of organic matter, floating extraction method is used to remove impurities and purify the high-concentration tantalum liquid and high-concentration niobium liquid obtained in the process. Finally, the separation and extraction of tantalum and niobium and the preparation of high-purity tantalum and niobium products are realized. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 is the process flow chart of the present application. DETAILED DESCRIPTION

[0034] The present application will be further described below in conjunction with specific embodiments. It should be noted that these embodiments are only for better understanding of the present application, and do not limit the scope of the present application.

[0035] Example 1

[0036] The composition of the rich tantalum and niobium organic phase obtained by conventional ore pulp extraction and acid washing stripping of tantalum and niobium decomposition solution is shown in Table 1:

[0037] Table 1 Concentration of each element in the rich tantalum and niobium organic phase

[0038]

[0039] The solution containing high-concentration niobium and low-concentration tantalum is obtained by using 0.5M H2SO4 solution for stripping, 3 extraction stages, 99.9% niobium stripping rate, and 4.5% tantalum stripping rate. The high-concentration tantalum liquid is obtained by performing tantalum stripping on the organic phase after niobium stripping.

[0040] The high concentration niobium and low concentration tantalum solution is subjected to floating extraction to extract tantalum, methyl isopropyl ketone and octanol-1 are added in a ratio of 1:1, the molar amount of the added is: tantalum molar amount in the solution = 2, the foaming stabilizer sorbitan monooleate is added at 1 g / L, the solution is stirred uniformly and air is introduced to obtain gas bubble-metal ion-flooding agent microdroplets, the floating time is 10 min, the floating stage is 1 stage, the tantalum floating efficiency is 99.8%, the niobium loss rate is 3.1%, and the high concentration niobium solution after purification is obtained.

[0041] The high concentration niobium solution is subjected to floating purification, di(2-ethylhexyl) phosphate is used as a floating agent in the first stage of floating purification, and cetyltrimethylammonium bromide is used as a foaming stabilizer, the floating agent is added at 2 g / L, and the foaming stabilizer is added at 0.1 g / L; octyl alcohol is used as a floating agent in the second stage of floating, and sorbitan monooleate is used as a foaming stabilizer, the floating agent is added at 2 g / L, and the foaming stabilizer is added at 0.1 g / L. After floating, the contents of tantalum, silicon, iron, tungsten, copper, titanium, nickel, antimony and tin are all less than 0.1 ppm, and the residual COD value of organic matter is 34 mg / L.

[0042] The high concentration tantalum solution is subjected to floating purification, and trioctylmethylammonium chloride is used as a floating agent, and cetyltrimethylammonium bromide is used as a foaming stabilizer, the floating agent is added at 1 g / L, and the foaming stabilizer is added at 0.5 g / L. After floating, the contents of niobium, silicon, iron, tungsten, copper, titanium, nickel, antimony and tin are all less than 0.1 ppm, and the residual COD value of organic matter is 23 mg / L.

[0043] The high concentration tantalum solution is heated to 85°C, the HF concentration is adjusted to 1.45 mol / L, KCl with a mass concentration of 300 g / L is added at 1.1 times the theoretical amount, and then the solution is water-cooled to room temperature, filtered and dried at 150°C to obtain potassium fluorotantalate product. The product purity is higher than 99.998% through chemical analysis.

[0044] Example 2

[0045] The composition of the tantalum-niobium-rich organic phase obtained by conventional ore slurry extraction and acid washing back-extraction is shown in Table 1.

[0046] The back-extraction is performed using a 0.25M H2SO4 solution, the extraction stage is 2, the niobium back-extraction rate is 99.9%, the tantalum back-extraction rate is 8.2%, and a solution containing high concentration niobium and low concentration tantalum is obtained. The organic phase after niobium back-extraction is subjected to tantalum back-extraction to obtain a high concentration tantalum solution.

[0047] The high concentration niobium and low concentration tantalum solution is subjected to floating extraction to extract tantalum, tri-octylmethyl ammonium chloride and sec-octyl alcohol are added in a ratio of 1:1, the molar amount of the added is: tantalum molar amount in the solution = 4, the total amount of the added is 1 g / L, the added is a foam stabilizer sorbitan monooleate and cetyl trimethyl ammonium bromide in a ratio of 1:4, stirring is uniform and air is introduced to obtain bubble-metal ion-floatation reagent microdroplets, the floatation time is 10 min, the floatation stage is 2 stages, the tantalum floatation efficiency is 99.9%, the niobium loss rate is 5.6%, and the high concentration niobium solution after purification is obtained.

[0048] The high concentration niobium solution is subjected to floating purification, di(2-ethylhexyl) phosphate is used as a floatation reagent in the first stage of floating purification, and sodium dodecyl sulfate is used as a foam stabilizer, the floatation reagent is added in an amount of 4 g / L, and the foam stabilizer is added in an amount of 0.2 g / L; n-octyl alcohol is used as a floatation reagent in the second stage of floating purification, and polyacrylamide is used as a foam stabilizer, the floatation reagent is added in an amount of 4 g / L, and the foam stabilizer is added in an amount of 0.2 g / L. After the floatation, the contents of tantalum, silicon, iron, tungsten, copper, titanium, nickel, antimony and tin are all less than 0.1 ppm, and the residual COD value of organic matter is 22 mg / L.

[0049] The high concentration tantalum solution is subjected to floating purification, tri-octylamine is used as a floatation reagent, and dodecyl trimethyl ammonium bromide is used as a foam stabilizer, the floatation reagent is added in an amount of 0.5 g / L, and the foam stabilizer is added in an amount of 0.1 g / L. After the floatation, the contents of niobium, silicon, iron, tungsten, copper, titanium, nickel, antimony and tin are all less than 0.1 ppm, and the residual COD value of organic matter is 42 mg / L.

[0050] The high concentration tantalum solution is heated to 85°C, the concentration of HF is adjusted to 1.45 mol / L, KCl with a mass concentration of 300 g / L is added in an amount of 1.1 times the theoretical amount, and then the solution is water-cooled to room temperature, filtered and dried at 150°C for 15 h to obtain potassium fluorotantalate product. The product purity reaches 5N through chemical analysis.

[0051] Example 3

[0052] The composition of the tantalum-niobium rich organic phase obtained by conventional ore pulp extraction and acid washing back-extraction is shown in Table 1.

[0053] The back-extraction is performed using 1M H2SO4 solution, the extraction stage is 3, the niobium back-extraction rate is 99.9%, the tantalum back-extraction rate is 2.3%, and the solution containing high concentration niobium and low concentration tantalum is obtained. The organic phase after the niobium back-extraction is subjected to tantalum back-extraction to obtain the high concentration tantalum solution.

[0054] The high concentration niobium and low concentration tantalum solution is subjected to floating extraction to extract tantalum, acetonamide and cyclohexanone are added in a ratio of 1:1, the molar amount of the added is: tantalum molar amount in the solution = 3, the total amount of the added foaming stabilizer polyacrylamide and sodium dodecyl sulfate is 1 g / L in a ratio of 1:4, stirring is uniform and air is introduced to obtain bubble-metal ion-floatation reagent microdroplets, the floating time is 10 min, the floating stage is 2 stages, the tantalum floating efficiency is 99.9%, the niobium loss rate is 3.5%, and the high concentration niobium solution after purification is obtained.

[0055] The high concentration niobium solution is subjected to floating purification, 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester is used as a floatation reagent in the first stage of floating purification, sodium dodecyl sulfate is used as a foaming stabilizer, the floatation reagent is added in an amount of 2 g / L, and the foaming stabilizer is added in an amount of 0.1 g / L; secondary flotation uses secondary carbon primary amine as a floatation reagent, and cetyltrimethylammonium bromide is used as a foaming stabilizer, the floatation reagent is added in an amount of 1 g / L, and the foaming stabilizer is added in an amount of 0.1 g / L. After flotation, the contents of tantalum, silicon, iron, tungsten, copper, titanium, nickel, antimony and tin are all less than 0.1 ppm, and the residual COD value of organic matter is 46 mg / L.

[0056] The high concentration tantalum solution is subjected to floating purification, trioctylamine is used as a floatation reagent, and dodecyltrimethylammonium bromide is used as a foaming stabilizer, the floatation reagent is added in an amount of 0.5 g / L, and the foaming stabilizer is added in an amount of 0.1 g / L. After flotation, the contents of niobium, silicon, iron, tungsten, copper, titanium, nickel, antimony and tin are all less than 0.1 ppm, and the residual COD value of organic matter is 34 mg / L.

[0057] Ammonia water with a mass concentration of 20% is added to the high concentration tantalum solution to adjust the pH to 8.5, then filtration is performed, the precipitate is washed with ammonia water for 3 times, the precipitate is dried at 200°C for 15 h, and after drying, the clean rotary tube furnace is used to calcine the precipitate at 850°C for 2 h, and the tantalum oxide product is obtained. Through analysis, it is found that the purity of the product reaches 5N.

[0058] Comparative Example 1

[0059] In the comparative example, the concentration of the stripping agent is too high.

[0060] The tantalum-niobium decomposition solution is subjected to conventional ore slurry extraction and acid washing stripping, and the composition of the tantalum-niobium rich organic phase obtained is shown in Table 1.

[0061] The 5M H2SO4 solution is used for stripping, the extraction stage is 10, the niobium stripping rate is 99.9%, the tantalum stripping rate is 1.0%, and the solution containing high concentration niobium and low concentration tantalum is obtained. The organic phase after niobium stripping is subjected to tantalum stripping operation, and the high concentration tantalum solution is obtained.

[0062] The high concentration niobium and low concentration tantalum solution was subjected to floating extraction to extract tantalum, methyl isopropyl ketone and octanol-1 were added in a ratio of 1:1, the molar amount of the added was: tantalum molar amount in the solution = 2, the foam stabilizer sorbitan monooleate was added at 0.2 g / L, the solution was stirred uniformly and air was introduced to obtain bubble-metal ion-floatation agent microdroplets, the floating time was 10 min, the floating stage was 1 stage, the tantalum floating efficiency was 99.8%, the niobium loss rate was 1.1%, and the high concentration niobium solution after purification was obtained.

[0063] The high concentration niobium solution was subjected to floating purification, di(2-ethylhexyl) phosphate was used as the floatation agent in the first stage of floating purification, and cetyltrimethylammonium bromide was used as the foam stabilizer, the floatation agent was added at 2 g / L, and the foam stabilizer was added at 0.1 g / L; octanol was used as the floatation agent in the second stage of floating, and sorbitan monooleate was used as the foam stabilizer, the floatation agent was added at 2 g / L, and the foam stabilizer was added at 0.1 g / L. After floating, the contents of tantalum, silicon, iron, tungsten, copper, titanium, nickel, antimony and tin were all less than 0.1 ppm, and the residual COD value of organic matter was 14 mg / L.

[0064] The high concentration tantalum solution was subjected to floating purification, trioctylmethylammonium chloride was used as the floatation agent, and cetyltrimethylammonium bromide was used as the foam stabilizer, the floatation agent was added at 1 g / L, and the foam stabilizer was added at 0.5 g / L. After floating, the contents of niobium, silicon, iron, tungsten, copper, titanium, nickel, antimony and tin were all less than 0.1 ppm, and the residual COD value of organic matter was 36 mg / L.

[0065] Comparative Example 2

[0066] In the comparative example, the high concentration niobium and low concentration tantalum solution was subjected to floating extraction to extract tantalum, and the amount of the floatation agent was too low.

[0067] The composition of the tantalum and niobium-rich organic phase obtained by conventional ore slurry extraction and acid washing back-extraction of the tantalum and niobium decomposition solution is shown in Table 1.

[0068] The solution containing high concentration niobium and low concentration tantalum was obtained by back-extraction with 0.25 M H2SO4 solution, 2 extraction stages, 99.9% niobium back-extraction rate, and 8.2% tantalum back-extraction rate. The organic phase after niobium back-extraction was subjected to tantalum back-extraction to obtain the high concentration tantalum solution.

[0069] The high concentration niobium and low concentration tantalum solution was subjected to floating extraction to extract tantalum, trioctylmethylammonium chloride and octanol were added in a ratio of 1:1, the molar amount of the added was: tantalum molar amount in the solution = 0.3, the foam stabilizers sorbitan monooleate and cetyltrimethylammonium bromide were added in a ratio of 1:4, the total amount of the added was 1 g / L, the solution was stirred uniformly and air was introduced to obtain bubble-metal ion-floatation agent microdroplets, the floating time was 10 min, the floating stage was 1 stage, the tantalum floating efficiency was 56.2%, and the niobium loss rate was 0.5%. The process ended here and could not be continued, or more stages of floating were required.

[0070] Comparative Example 3

[0071] In this comparative example, the dosage of the floatation reagent is too low when the high-concentration niobium solution is purified by floatation.

[0072] The high-concentration niobium solution obtained in Example 1 was purified by floatation.

[0073] The high-concentration niobium solution was purified by floatation. The primary floatation purification used di(2-ethylhexyl) phosphate as the floatation reagent and sodium dodecyl sulfate as the foam stabilizer, the dosage of the floatation reagent was 0.05 g / L, and the dosage of the foam stabilizer was 0.1 g / L. The secondary floatation used n-octanol as the floatation reagent and polyacrylamide as the foam stabilizer, the dosage of the floatation reagent was 0.05 g / L, and the dosage of the foam stabilizer was 0.1 g / L. After the floatation, the contents of tantalum, silicon, iron, tungsten, copper, titanium, nickel, antimony, and tin were not less than 0.1 ppm, the concentration of the impurity elements was still high, the COD value of the residual organic matter was 230 mg / L, and the residual organic matter was too much, which affected the preparation of the high-purity niobium product.

[0074] Comparative Example 4

[0075] In this comparative example, the type of the floatation reagent used when the high-concentration niobium solution is purified by floatation is not within the scope of the present application.

[0076] The high-concentration niobium solution obtained in Example 1 was purified by floatation.

[0077] The high-concentration niobium solution was purified by floatation. The primary floatation purification used diethylbenzene as the floatation reagent and sodium dodecyl sulfate as the foam stabilizer, the dosage of the floatation reagent was 2 g / L, and the dosage of the foam stabilizer was 0.2 g / L. The secondary floatation used sulfonated kerosene as the floatation reagent and polyacrylamide as the foam stabilizer, the dosage of the floatation reagent was 3 g / L, and the dosage of the foam stabilizer was 0.1 g / L. After the floatation, the contents of tantalum, silicon, iron, tungsten, copper, titanium, nickel, antimony, and tin were not less than 0.1 ppm, the concentration of the impurity elements was still high, which affected the preparation of the high-purity niobium product, and the COD value of the residual organic matter was 24 mg / L.

[0078] Comparative Example 5

[0079] In this comparative example, the dosage of the foam stabilizer is too high when the high-concentration tantalum solution is purified by floatation.

[0080] The high-concentration tantalum solution obtained in Example 1 was purified by floatation.

[0081] The high concentration tantalum liquid is subjected to flotation purification, and trioctylmethylammonium chloride is used as the flotation agent, and cetyltrimethylammonium bromide is used as the foam stabilizer, the addition amount of the flotation agent is 1 g / L, and the addition amount of the foam stabilizer is 2 g / L. After flotation, the contents of niobium, silicon, iron, tungsten, copper, titanium, nickel, antimony and tin are all less than 0.1 ppm, and the residual COD value of the organic matter is 346 mg / L, and the residual organic matter is relatively high, which affects the preparation of high-purity niobium products.

[0082] Comparative Example 6

[0083] In the comparative example, the type of the foam stabilizer used in the flotation purification of the high concentration tantalum liquid is not within the range of the present application.

[0084] The high concentration tantalum liquid obtained in Example 1 is subjected to flotation purification.

[0085] The high concentration tantalum liquid is subjected to flotation purification, and trioctylmethylammonium chloride is used as the flotation agent, and sodium hexametaphosphate is used as the foam stabilizer, the addition amount of the flotation agent is 1 g / L, and the addition amount of the foam stabilizer is 0.2 g / L. After flotation, the contents of niobium, silicon, iron, tungsten, copper, titanium, nickel, antimony and tin are all not less than 0.1 ppm, the concentrations of impurity elements are still relatively high, the residual COD value of the organic matter is 289 mg / L, and the residual organic matter is relatively high, which affects the preparation of high-purity niobium products.

Claims

1. A method for purifying tantalum and niobium liquid based on floating extraction, characterized in that, The method comprises the following steps: The tantalum-niobium decomposition solution is extracted by ore pulp, and the rich tantalum-niobium organic phase obtained by acid washing and back extraction is subjected to niobium back extraction to obtain a solution containing high-concentration niobium and low-concentration tantalum; The high-concentration niobium and low-concentration tantalum solution is subjected to selective extraction of tantalum by floating extraction, the floating extraction method is to add a floating extraction agent and a foam stabilizer into the solution, air is introduced to form micro-bubbles, the bubbles are hydrophobic and mineralized to form fluorotantalate-flooding agent-bubble micro-droplets, the droplets rise to the surface of the organic phase in the solution, and high-concentration niobium solution and low-concentration tantalum-niobium organic phase are obtained; The low-concentration tantalum-niobium organic phase is returned to the rich tantalum-niobium organic phase in the process for next operation; The high-concentration niobium solution still contains impurity elements other than niobium and residual organic matter in water, and is subjected to floating purification to obtain clean and pure niobium solution, and the organic phase after niobium back extraction is subjected to tantalum back extraction to obtain a high-concentration tantalum solution, wherein impurity elements other than tantalum and residual organic matter are removed by floating purification to obtain clean tantalum solution; The clean tantalum solution and the clean niobium solution are treated by neutralization and precipitation or salting-out, respectively, the obtained solid products are dried or calcined to remove water, and finally high-purity tantalum and high-purity niobium products are obtained, respectively; The niobium back extraction agent is at least one of sulfuric acid, hydrochloric acid, nitric acid, phosphoric acid and hydrofluoric acid, the concentration of the back extraction agent is 0.1-4.5 mol / L, and the back extraction stage is less than 5; The floating extraction agent added in the floating extraction of the high-concentration niobium and low-concentration tantalum solution comprises one or a combination of ketones, amides, alcohols and amines, the ketones comprise at least one of methyl isopropyl ketone, cyclohexanone and alkyl ketones with a carbon chain length of 5-8, the amides comprise at least one of acetamide and N, N-dimethyl mixed alkyl acetamide, the amines comprise at least one of trioctylmethyl ammonium chloride, trioctylamine and secondary carbon primary amine, and the alcohols comprise at least one of secondary octanol, octanol-1 and amyl alcohol, and at least one of sorbitan monooleate, sodium dodecyl sulfate, polyacrylamide and alkyl trimethyl ammonium bromide is added as a foam stabilizer, the molar ratio of the floating extraction agent to tantalum is 0.5-10, the foam stabilizer is added in an amount of 0.01-2 g / L, and the flotation stage is 1-2 stages; the alkyl trimethyl ammonium bromide has a carbon chain length of 12-16; The floating purification agent added in the floating purification of the high-concentration niobium solution and the high-concentration tantalum solution comprises one or a combination of amines, phosphate esters and alcohols, the amines comprise at least one of trioctylmethyl ammonium chloride, trioctylamine and secondary carbon primary amine, the phosphate esters comprise at least one of di(2-ethylhexyl) phosphate, 2-ethylhexyl monophosphate, tributyl phosphate and dibutyl phosphate, and the alcohols comprise isopentyl alcohol, secondary octanol and n-octanol, at least one of alkyl trimethyl ammonium bromide, sodium dodecyl sulfate, sorbitan monooleate, sorbitan monooleate and polyacrylamide is added as a foam stabilizer, the floating extraction agent is added in an amount of 0.05-10 g / L, the foam stabilizer is added in an amount of 0.01-2 g / L, and the flotation stage is 1-2 stages; the alkyl trimethyl ammonium bromide has a carbon chain length of 12-16. When high-concentration niobium solution is subjected to floating purification, In the first-stage floating purification, phosphoric acid ester is used as the floating agent, and at least one of cetyltrimethylammonium bromide and sodium dodecyl sulfate is used as the foam stabilizer, wherein the floating agent is added in an amount of 2-4 g / L, and the foam stabilizer is added in an amount of 0.1-0.2 g / L; In the second-stage floating purification, alcohol and / or amine is used as the floating agent, and at least one of sorbitan monooleate, polyacrylamide and cetyltrimethylammonium bromide is used as the foam stabilizer, wherein the floating agent is added in an amount of 1-4 g / L, and the foam stabilizer is added in an amount of 0.1-0.2 g / L; When high-concentration tantalum solution is subjected to floating purification, amine is used as the floating agent, and alkyltrimethylammonium bromide is used as the foam stabilizer, wherein the floating agent is added in an amount of 0.5-1.5 g / L, and the foam stabilizer is added in an amount of 0.1-0.5 g / L.

2. The method for purifying tantalum and niobium liquid based on floating extraction according to claim 1, characterized in that: The tantalum and niobium-rich organic phase is subjected to stripping, and the stripping agent is at least one of sulfuric acid, hydrochloric acid, nitric acid, phosphoric acid and hydrofluoric acid, and the concentration of the stripping agent is 0.1-4 mol / L, and the stripping stage is 1-3 stages.

3. The method for purifying tantalum and niobium liquid based on floating extraction according to claim 2, characterized in that: When the tantalum and niobium-rich organic phase is subjected to stripping, the concentration of the stripping agent is 0.25-1 mol / L.

4. The method for purifying tantalum and niobium liquid based on floating extraction according to claim 1, characterized in that: In the high-concentration niobium and low-concentration tantalum solution, the concentration of niobium is 25-150 g / L, and the concentration of tantalum is 0.1-10 g / L.

5. The method for purifying tantalum and niobium liquid based on floating extraction according to claim 1, characterized in that: The solid precipitate produced by neutralization and precipitation or salting-out of the clean tantalum solution and the clean niobium solution is dried or calcined to obtain high-purity tantalum and high-purity niobium products, respectively.

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