An extraction and separation method for a high-fluoride beryllium sulfate solution

Abstract

The present invention belongs to the field of metallurgical technology and relates to an extraction and separation method for a high-fluorine beryllium sulfate solution, comprising: S1. Pretreatment: adjusting the pH of the high-fluorine beryllium sulfate solution to 4.0 - 4.8 with sodium alkali, heating to 80 - 90 °C and reacting for 30 - 45 min, then introducing air and adding a bone glue solution and activated carbon at a mass concentration of 10 - 25 mL / L, filtering to obtain a pretreated solution, and standing for clarification; S2. Extraction: extracting the pretreated solution after standing for clarification; the high-fluorine beryllium sulfate solution contains: Fe 1.3 - 3.5 g / L, Al 8.0 - 15.0 g / L, F 10.0 - 35.0 g / L, SiO2 0.2 - 0.5 g / L. The present invention makes full use of the properties of aluminum, fluorine, iron, and silicon in the beryllium sulfate solution, maximally separates them, removes harmful impurities step by step, and ensures the quality of the final product beryllium oxide from the source.

Description

Technical Field

[0001] The present invention belongs to the technical field of metallurgy, and particularly relates to an extraction separation method for a high-fluorine beryllium sulfate solution. Background Art

[0002] At present, one of the production methods for obtaining beryllium oxide is the sulfuric acid method. However, the sulfuric acid method requires that the fluorine-beryllium ratio in the ore is less than 10%; and it can only process high-grade beryllium ores with a beryllium oxide content of 6% - 11%. The production of high-purity beryllium by the sulfuric acid method is mainly obtained by melting and acid leaching the beryllium-containing ore with a formulated mixture, and then obtaining a beryllium sulfate solution. Then, aluminum is removed by evaporation using the ammonium aluminum sulfate crystallization method, iron is removed by neutralization, and hydrolysis precipitation is carried out to obtain beryllium hydroxide. Beryllium hydroxide is redissolved, impurities are removed, and neutralization precipitation is carried out to obtain refined beryllium hydroxide. The refined beryllium hydroxide is decomposed at high temperature to obtain high-purity beryllium oxide. Its process is long, the cost is high, the direct yield and total yield in the production process are low, and incomplete impurity removal will also affect the quality of beryllium oxide or beryllium beads in subsequent processes.

[0003] With the continuous consumption of beryl-type beryllium-containing ores with a grade of 6% - 11%, non-beryl beryllium-containing ores will become the main raw materials for beryllium smelting. Such raw materials are characterized by low beryllium content and high impurity content. Especially those raw materials with a relatively high fluorine content (fluorine-beryllium ratio in the ore ≥ 10%) and also containing a large amount of iron, aluminum, and machine oil are particularly difficult to process, and there is currently no relevant industrialization report in China.

[0004] The prior art 201611014052.X discloses a method for producing fluoberyllic acid and ammonium fluoberyllate from a beryllium sulfate solution, including the following steps: (1) After adjusting the pH value of the beryllium sulfate solution, it is extracted with an iron extraction agent to obtain an iron-extracted post-liquid and an iron-loaded organic phase; (2) The iron-extracted post-liquid is extracted with a beryllium extraction agent to obtain a beryllium-extracted post-liquid and a beryllium-loaded organic phase; (3) The beryllium-loaded organic phase is washed by a multi-stage countercurrent washing with a mixed solution of oxalic acid and sodium sulfite to obtain a washed organic phase and washing water; (4) The washed organic phase is back-extracted with a hydrofluoric acid solution to obtain a fluoberyllic acid solution; this method shortens the process flow of beryllium production, improves the recovery rate of beryllium, reduces production costs, and stabilizes the quality of beryllium. However, this prior art cannot process beryllium concentrates with a high F content. At the same time, when the aluminum content in the beryllium sulfate solution is relatively high, it not only affects the extraction effect of beryllium but also affects the quality of subsequent beryllium products. Moreover, in the back-extraction process, an unconventional reagent, hydrofluoric acid, is used, which requires strict equipment requirements, high production costs, and can only process beryllium sulfate solutions with a beryllium content of 1 - 5 g / L.

[0005] The prior art CN 114908259 B provides a method for selectively extracting beryllium from beryllium-containing sludge based on hydrothermal mineral phase regulation, which includes the following steps: S1, drying the beryllium-containing sludge and grinding it into a ground product; S2, mixing the ground product with a sodium persulfate solution and performing hydrothermal treatment to obtain a solid-liquid mixture; S3, sequentially performing cooling treatment and solid-liquid separation on the solid-liquid mixture to obtain a beryllium-containing filtrate and a residue after beryllium removal. This method uses salts as leaching agents and hydrothermal treatment to enable beryllium to efficiently and selectively enter the liquid phase, while impurity elements such as aluminum, silicon, and iron remain in the solid phase, obtaining a high-purity beryllium-containing filtrate that can be industrially utilized and a residue with greatly reduced environmental harm, effectively avoiding environmental pollution caused by beryllium-containing sludge. However, this method uses the strong oxidation of sodium persulfate to acid-leach beryllium, iron, and aluminum under high temperature and high pressure (the temperature of hydrothermal treatment is 150-180 °C), and separates impurity iron and aluminum under an oxidative atmosphere, separating during leaching, causing a large amount of pollution; at the same time, under the conditions of high temperature and high pressure of strong oxidants, the equipment investment cost is high, the production cost is high, and the relative risk coefficient during the production process is significantly greater.

[0006] The prior art CN 103468975 B provides a method and its application for separating beryllium from beryllium-containing impure hydroxide using a chloride system. The method includes: dissolving beryllium-containing impure hydroxide with a hydrochloric acid solution to obtain a hydrochloric acid acidolysis solution, and using an extractant for extraction to obtain a loaded organic phase and a beryllium-rich raffinate. The method provided by this invention can separate beryllium from impurities in beryllium-containing impure hydroxide to obtain a beryllium-rich raffinate, thereby purifying beryllium-containing impure hydroxide. The separation of beryllium and impurities by this method is relatively thorough, the recovery rate of beryllium in beryllium-containing impure hydroxide is high, the process is simple, and it is easy to be popularized and used on a large scale. However, this method removes impurities and retains valuable metal beryllium in the aqueous phase; this method can only process easily acid-soluble beryllium hydroxide raw materials and cannot process various beryllium ores, with a single raw material for treatment; at the same time, the system of this method is a hydrochloric acid system, and hydrochloric acid is volatile, has an irritating odor, and seriously corrodes equipment.

[0007] The prior art (New process research on producing industrial beryllium oxide by alkali dissolution and hydrolysis method) uses the alkali dissolution and hydrolysis method to produce industrial beryllium oxide, eliminating the two processes of evaporation crystallization for aluminum removal and neutralization for iron removal. Aluminum mainly enters the hydrolysis waste liquid as sodium metaaluminate, without generating ammonium alum slag. Producing 1t of industrial beryllium oxide reduces about 20t of alum slag, and can increase the recovery rate of beryllium oxide by 4% - 5%. Although this process does not have a neutralization for iron removal process, iron slag still exists (the mixed precipitate of beryllium, iron, and aluminum still has iron slag after alkali dissolution). These iron slags contain very little aluminum, and the flow rate is only about half of that of the iron slag in the sulfuric acid method. If the more advanced goethite method is used to wash the iron slag, the beryllium content in the iron slag can be reduced to less than 0.5%, and the recovery rate of beryllium oxide can be increased by 8% - 10% compared with the sulfuric acid method. However, this invention adds two processes of alkali dissolution and hydrolysis. Although no alum slag is generated, a large amount of hydrolysis waste liquid is produced, resulting in a beryllium loss of more than 2%. The iron slag precipitates as colloidal ferric hydroxide, which is difficult to filter. The iron slag is washed by the goethite method, the process is complex, and the beryllium oxide content in the slag reaches 0.5%, belonging to hazardous waste materials, which are difficult to stack; the beryllium-iron-aluminum slag is alkali-dissolved at a high temperature of 115 degrees, belonging to special equipment under high temperature and high pressure, with large investment and high safety risks. Summary of the Invention

[0008] The object of the present invention is to provide a method for extracting and separating a high-fluoride beryllium sulfate solution.

[0009] To solve the above technical problems, the technical solution of the present invention is as follows:

[0010] A method for extracting and separating a high-fluoride beryllium sulfate solution, comprising the following steps:

[0011] S1. Pretreatment: Adjust the pH of the high-fluoride beryllium sulfate solution to 4.0 - 4.8 with sodium alkali, heat it to 80 - 90 °C and react for 30 - 45 min, then introduce air, react for 60 - 180 min, add a bone glue solution at a mass concentration of 10 - 25 mL / L, then add activated carbon, filter to obtain a pretreated solution, and let it stand for clarification;

[0012] S2. Extraction: Extract the pretreated solution after standing for clarification. In the extraction, the volume ratio of the oil phase to the water phase (O / A) = 1:0.5 - 5, and the extraction time is 4 - 8 min to obtain a raffinate and a loaded organic phase; the oil phase refers to the mixed organic phase of an extractant, a diluent, and a synergistic extractant;

[0013] S3. Acid washing: Acid wash the loaded organic phase. In the acid washing, the volume ratio of the oil phase to the acid washing agent (O / A) is 1 - 4:1, and the acid washing time is 1 - 5 min to obtain an acid-washed solution and an acid-washed organic phase;

[0014] S4. Back extraction: The pickled organic phase is subjected to back extraction. In the back extraction, the volume ratio of the oil phase to the back extractant (O / A) is 1 - 3:1, the back extraction time is 4 - 15 min, and the back extraction temperature is 50 - 56 °C, obtaining the post-back extraction liquid and the post-back extraction organic phase;

[0015] S5. High-temperature hydrolysis: The post-back extraction liquid obtained in step S4 is added to pure water for high-temperature hydrolysis. The volume ratio of pure water to the post-back extraction liquid is 3 - 8:1, the hydrolysis temperature is 85 - 98 °C, and the high-temperature hydrolysis time is 4 - 8 h, obtaining beryllium hydroxide;

[0016] S6. Calcination: The beryllium hydroxide is calcined at 850 - 940 °C for 2 - 5 h, obtaining beryllium oxide products;

[0017] The high-fluorine beryllium sulfate solution contains: Fe 1.3 - 3.5 g / L, Al 8.0 - 15.0 g / L, F 10.0 - 35.0 g / L, SiO₂ 0.2 - 0.5 g / L.

[0018] Through the pretreatment of the present invention, the service life of the organic phase is extended, the possibility of emulsification and aging of the organic phase is reduced, the extraction ability of the organic phase is enhanced, the usage amount of the organic phase is reduced under the condition of a unit aqueous phase (i.e., the O / A ratio is reduced), thereby reducing the production cost; in the pickling process, the usage amount of the pickling agent is reduced under the condition of a unit oil phase, and to a certain extent, the pickling stage number and pickling time can be reduced, reducing the production cost.

[0019] In one preferred embodiment, in step S1, the pH of the high-fluorine beryllium sulfate solution is adjusted to 4.0 - 4.8 with sodium base; preferably, the sodium base is sodium hydroxide, sodium bicarbonate, or sodium carbonate.

[0020] In one preferred embodiment, the mass concentration of the sodium base is 25 - 30%.

[0021] Adding sodium base to adjust the pH of the high-fluorine beryllium sulfate solution to 4.0 - 4.8, and using the impurities F and Al in the beryllium sulfate solution and Na in the sodium base to carry out the cryolite preparation reaction, generating sodium hexafluoroaluminate particles with easy filtration performance, i.e., cryolite. On the one hand, it is used to remove high-content fluorine, and on the other hand, using cryolite as a seed crystal, air is blown in at 80 - 90 °C to oxidize Fe 2+ to Fe 3+ , generating easily filterable iron hydroxide precipitate.

[0022] The hydrolysis amount of beryllium is less when the pH is 4, and a large amount of hydrolysis starts when the pH is greater than 5. When the pH is too low, the cryolite preparation reaction degree is small, and F removal is incomplete, resulting in F being carried into the back extractant during the back extraction process of the extraction process, affecting the hydrolysis of the back extractant and incomplete beryllium precipitation; when the pH is too high, F precipitation is complete, but a large amount of beryllium is hydrolyzed and precipitated into the slag, and the beryllium recovery rate decreases.

[0023] The reaction time is 30 - 45 min. If the time is too short, the reaction is incomplete, and there is still residual F in the solution. At the same time, supersaturated cryolite will be retained in the aqueous phase. If the time is too long, the production cost will increase, and the possibility of beryllium hydrolysis will also increase, resulting in a decrease in beryllium recovery rate.

[0024] Air is introduced at 80 - 90 °C, and the reaction occurs for 60 - 180 min. The reaction uses air as an intensifier, and an oxidation reaction occurs at high temperature to oxidize Fe 2+ to Fe 3+ , and then using cryolite as a seed crystal to form filterable ferric hydroxide precipitate particles.

[0025] In one preferred embodiment, the amount of air introduced is 3 - 12 times the theoretical amount of oxygen required to oxidize ferrous iron to ferric iron.

[0026] In one preferred embodiment, the air can also be oxygen-enriched air, hydrogen peroxide, and sodium persulfate that do not introduce additional impurities. The amount of oxygen-enriched air introduced is 2 - 5 times the theoretical amount of oxygen required to oxidize ferrous iron to ferric iron, and the addition amounts of hydrogen peroxide and sodium persulfate are 1.5 - 2.3 times and 1.1 - 1.5 times the theoretical amount of oxygen required to oxidize ferrous iron to ferric iron, respectively.

[0027] In one preferred embodiment, after introducing air, stirring is maintained, and the stirring speed is 350 - 500 revolutions per minute.

[0028] Maintaining within this temperature, stirring speed, and reaction time range can precipitate iron impurities to the greatest extent.

[0029] In one preferred embodiment, the mass percentage concentration of the bone glue solution is 15 - 25%.

[0030] In one preferred embodiment, the stirring speed is 100 - 180 revolutions per minute after adding bone glue.

[0031] The purpose of adding bone glue is to remove SiO2 and Fe(OH)3 colloids. Through a large number of experiments, it is proved that at a suitable stirring speed, maintaining the mass concentration of the bone glue solution in the system within 10 - 25 mL / L can ensure complete removal of silica gel, enhance the filtration performance, reduce the possibility of organic phase aging and emulsification in the subsequent extraction stage, and improve the extraction ability of beryllium; at the same time, it does not increase the colloidal substances generated by bone glue and affect the filtration performance; if it is too low, the removal is incomplete, and if it is too high, it is too strong locally, resulting in an emulsified solution that cannot be filtered.

[0032] In one preferred embodiment, the addition amount of activated carbon is 2 - 5 g / L.

[0033] By adding activated carbon to adsorb colloid, fine particles and the organic phase in the solution, the aging and emulsification of the organic phase in the beryllium extraction process are reduced, and the service life of the organic phase is prolonged.

[0034] In one preferred embodiment, the clarification time is 16 - 32 h, and the mass concentration of the solid content in the pretreated liquid after clarification is 10 - 20 mg / L.

[0035] In one preferred embodiment, in the oil phase, the volume percentage concentrations of the extractant, co - extractant, and diluent are 25 - 35%: 10 - 15%: 50 - 65% respectively.

[0036] In one preferred embodiment, the extractant is one or a mixture of two of 2 - ethylhexyl phosphoric acid, bis(2 - ethylhexyl) phosphate, and tributyl phosphate, the diluent is sulfonated kerosene or 260# solvent oil, and the co - extractant is isoamyl alcohol.

[0037] During the pretreatment process, 100% removal is not achieved, and only the removal rate of F after pretreatment can be guaranteed to exceed 85%. During the extraction process, by adjusting the selection and ratio of the extractant, co - extractant, and diluent, while ensuring the extraction ability of Be, separation from calcium, magnesium, and fluorine is achieved, and part of the iron and aluminum are further separated from beryllium, so that F is not extracted.

[0038] Through a large number of experimental verifications, the proportion of the extractant can be increased as much as possible, but the viscosity is too high. The diluent can reduce the viscosity of the organic phase, and the co - extractant can improve the extraction ability and extraction speed of beryllium. At the same time, a suitable ratio can reduce the extraction of impurities; if the proportion of the extractant is too low, the extraction rate of beryllium cannot meet the requirements, and the recovery rate of beryllium decreases.

[0039] In one preferred embodiment, the pickling agent is a mixed solution of oxalic acid and sulfite or bisulfite.

[0040] In one preferred embodiment, the pickling agent is a mixed solution of oxalic acid with a mass percentage concentration of 3 - 7% and a soluble sulfite or bisulfite with a mass concentration of 3 - 5 g / L.

[0041] The soluble sulfite or bisulfite in the pickling agent refers to Na2SO3, K2SO3, (NH4)2SO3, NaHSO3, KHSO3, NH4HSO3 respectively.

[0042] The oxalic acid used for pickling in step C is to remove Fe 2+ and Al 3+ , and its removal rate exceeds 99%, ensuring the effective separation of impurity iron, aluminum, and fluorine from beryllium in the last step; the sulfite ion or bisulfite ion in the pickling agent can react with Fe 3+ in the loaded organic phase to form Fe2+ and oxidize sulfite ions or bisulfite ions into sulfate ions, and reduce the Fe that was not completely removed in the pretreatment and was extracted into the loaded organic phase during the extraction process 3+ to Fe 2+ , so that it can be completely eluted by pickling. This not only prevents the organic phase from aging or emulsifying due to residual Fe 3+ , but also ensures that iron is completely removed and separated in the pickling section, avoiding the entry of Fe 3+ into the stripping solution during the stripping process, thus reducing the possibility of deteriorating the quality of the product beryllium oxide.

[0043] The selection and ratio of reagents in the pickling solution have been optimized many times. If the reagents, ratio, and the ratio of the oil phase to the pickling agent are not appropriate and the technical indicators cannot be met, and the impurities cannot be completely removed, it may affect the product grade and may also cause the emulsification of the organic phase. For example, if the iron pickling is not in place and enters the stripping solution, the iron will immediately be oxidized to trivalent iron, forming iron slag, which will reduce the product quality; when trivalent iron ions enter the organic phase, the organic phase will age and emulsify, making the production impossible to proceed. At the same time, the stripping is incomplete and the recovery rate of beryllium decreases. Pickling according to the method of the present invention results in a beryllium loss of less than 1%, and the impurity removal rate exceeds 88%, meeting the process requirements.

[0044] In one preferred embodiment, the stripping agent refers to a sodium hydroxide or potassium hydroxide solution with a mass molar concentration of 3.5 - 7 moL / L.

[0045] In one preferred embodiment, the hydrolysis temperature is 85 - 94 °C.

[0046] When the hydrolysis temperature is 82 °C, the beryllium content in the hydrolyzed solution is greater than 0.1 g / L, and the recovery rate of beryllium in the hydrolysis process is about 95%. When the temperature is 98 °C, a large amount of water evaporates, and impurities calcium and magnesium deposit into beryllium hydroxide, resulting in the product quality not meeting the standard and increasing the production cost at the same time; performing under the hydrolysis conditions of 85 - 94 °C can produce high-purity beryllium hydroxide products, and the recovery rate of beryllium exceeds 99%.

[0047] In one preferred embodiment, the extraction and separation method further includes regenerating the organic phase after stripping with a regenerant.

[0048] In one preferred embodiment, the regenerant is a sulfuric acid solution with a mass molar concentration of 2 - 3 moL / L.

[0049] In one preferred embodiment, the organic phase after stripping is regenerated. The number of regeneration stages is 3 - 4, the volume ratio of the oil phase to the regenerant (O / A) in each stage of regeneration is 1 - 5:1, and the regeneration time is 2 - 8 min to obtain the regenerated solution and the regenerated organic phase.

[0050] The purpose of regeneration is to replace the cations in the extractant in the organic phase with H+ Replacement, removal of impurity ions, and regeneration of the organic phase.

[0051] In one preferred embodiment, the extraction and separation method further includes a clarification step.

[0052] In one preferred embodiment, clarification steps are designed between the last extraction stage and the pickling stage, between the last pickling stage and the stripping stage, and between the last stripping stage and the regeneration stage, and the clarification time is 15 - 30 min.

[0053] The beneficial effects of the present invention are as follows:

[0054] (1) In the pretreatment process of the present invention, the properties of aluminum, fluorine, iron, and silicon in the beryllium sulfate solution are fully utilized to separate them from beryllium to the maximum extent. At the same time, harmful impurities are removed step by step through the beryllium extraction process, ensuring the quality of the final product beryllium oxide from the source.

[0055] (2) Through the preliminary impurity removal in the pretreatment process and the deep impurity removal, purification, and enrichment of beryllium in the organic phase extraction process of the present invention, the problems of separation, enrichment, and purification from beryllium sulfate solutions containing impurities such as iron, aluminum, fluorine, and silicon dioxide are solved. High-quality and high-purity beryllium oxide products are prepared, ensuring the quality of subsequent beryllium processing for other products, reducing the requirements for beryllium grade and impurities such as F, Si, Fe, and Al in beryllium ore during beryllium smelting, broadening the raw materials required for beryllium smelting, and providing a new and effective beryllium extraction method for smelting beryllium from fluorine-containing beryllium ore.

[0056] (3) The present invention has the advantages of reasonable process, low production cost, environmental friendliness, non-toxicity, etc., is easy to industrialize, and has a very broad application prospect. At the same time, the present invention has low requirements for the BeO content in the beryllium sulfate solution, and can treat solutions with a BeO content below 1 g / L or solutions with a BeO content exceeding 10 g / L. The purity of the prepared beryllium oxide reaches 99.6%, and the extraction rate and stripping rate of beryllium both exceed 99%. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] Figure 1 Process flow chart of Embodiment 1 of the present invention DETAILED DESCRIPTION OF THE INVENTION

[0058] In order to make the technical problems, technical solutions, and beneficial effects solved by the present invention clearer, the present invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. The present invention includes other embodiments and their deformations within the scope of its technical idea.

[0059] In the present invention, sometimes certain types of auxiliary materials are added or reduced according to different types of impurities in the beryllium sulfate solution. However, as long as the basic process flow remains unchanged, it also falls within the protection scope of the present invention.

[0060] The embodiment of the present invention provides an extraction and separation method for a beryllium sulfate solution containing impurities such as iron, aluminum, fluorine, and silicon dioxide. The process flow is referred to Figure 1 . The present invention will be further described below through specific embodiments.

[0061] Example 1

[0062] The main components of the beryllium sulfate solution have provided the mass concentration of the main components (g / L) as BeO 0.73, Fe 3.25, Al 12.17, F 12.87, SiO2 0.39. As Figure 1 shown, the method of the present invention includes the following steps:

[0063] 1. Pretreatment step: Turn on the stirring intensity of the beryllium sulfate solution tank to 500 revolutions per minute. While heating up to 90 °C, adjust the pH = 4.0 with liquid caustic soda. After reacting for 30 minutes, then introduce air for preliminary iron removal. After reacting for 60 minutes, reduce the stirring intensity to 100 revolutions per minute. Then add a 25% bone glue solution at a mass concentration of 25 mL / L. Before filtration, add activated carbon at a mass concentration of 5 g / L. Filter and clarify for 32 hours. The mass concentration of the solid content in the clarified pretreatment liquid is 10 mg / L;

[0064] 2. Be extraction step: In the prepared organic phase, 2-ethylhexyl phosphoric acid: isopentanol: sulfonated kerosene = 35:10:55. Perform Be extraction on the static pretreatment liquid obtained in step A in a box-type mixer-settler. The extraction stage is 4 stages, O / A = 1:5, extraction time = 8 minutes, extraction temperature is the process temperature, and clarification time is 10 minutes to obtain a raffinate and a loaded organic phase;

[0065] 3. Pickling step: Mix the loaded organic phase obtained in step B with a pickling agent of 7% oxalic acid + 3 g / L (NH4)2SO3 for pickling. The pickling stage is 2 stages, O / A = 4:1, pickling time = 5 minutes, pickling temperature is the process temperature, and clarification time is 7 minutes to obtain a pickled solution and a pickled organic phase;

[0066] 4. Back-extraction step: Perform back-extraction on the pickled organic phase obtained in step C with a 7 moL / L sodium hydroxide back-extraction agent. The back-extraction stage is 3 stages, O / A = 3:1, t = 15 minutes, T = 50 °C, and clarification time is 20 minutes to obtain a back-extracted solution and a back-extracted organic phase;

[0067] 5. Regeneration step: The organic phase after back extraction obtained in step D is regenerated with a 3 mol / L regenerant. The number of regeneration stages is 3, O / A = 5:1, t = 2 min, the regeneration temperature is the process temperature, and the clarification time is 8 min to obtain the regenerated liquid and the regenerated organic phase.

[0068] 6. High-temperature hydrolysis step: The back-extracted liquid obtained in step D is added to pure water for high-temperature hydrolysis. The volume ratio of pure water to the back-extracted liquid is 3:1, T = 85 °C, t = 8 h to obtain beryllium hydroxide.

[0069] 7. Calcination step: The beryllium hydroxide obtained in step G is calcined, T = 940 °C, t = 2 h to obtain a high-purity beryllium oxide product.

[0070] Through the extraction separation and preparation of the impure beryllium sulfate solution this time, a high-purity beryllium oxide product with a purity of 99.68% is obtained. The extraction rate and back-extraction rate of beryllium reach 99.42% and 99.48% respectively. The slag rate of the pretreatment slag is 26% of the slag rates of conventional bauxite slag and iron slag, and the total recovery rate of beryllium reaches 98.05%.

[0071] Comparative Example 1

[0072] The main components of the beryllium sulfate solution have provided the mass concentrations of the main components (g / L): BeO 0.73, Fe 3.25, Al 12.17, F 12.87, SiO2 0.39. It includes the following steps:

[0073] 1. Pretreatment step: The stirring intensity of the beryllium sulfate solution tank is turned on to 500 revolutions per minute. While heating up to 90 °C, the pH is adjusted to 5.0 with liquid caustic soda. After reacting for 30 min, air is then introduced for preliminary iron removal. After reacting for 60 min, the stirring intensity is reduced to 100 revolutions per minute, and then a 25% bone glue solution is added at a mass concentration of 25 mL / L. Before filtration, activated carbon is added at a mass concentration of 5 g / L, and it is filtered and clarified for 32 h. The mass concentration of the solid content in the clarified pretreatment liquid is 10 mg / L.

[0074] 2. Be extraction step: In the prepared organic phase, 2-ethylhexyl phosphoric acid: isoamyl alcohol: sulfonated kerosene = 35:10:55. The static pretreatment liquid obtained in step A is subjected to Be extraction in a box-type mixer-settler. The number of extraction stages is 4, O / A = 1:5, the extraction time = 8 min, the extraction temperature is the process temperature, and the clarification time is 10 min to obtain the raffinate and the loaded organic phase.

[0075] 3. Pickling step: Mix the loaded organic phase obtained in step B with a pickling agent of 7% oxalic acid + 3 g / L (NH4)2SO3 for pickling. The pickling stage is 2 stages, O / A = 4:1, pickling time = 5 min, pickling temperature is the process temperature, and clarification time is 7 min to obtain the pickled solution and the pickled organic phase;

[0076] 4. Stripping step: Strip the pickled organic phase obtained in step C with a 7 moL / L sodium hydroxide stripping agent. The stripping stage is 3 stages, O / A = 3:1, t = 15 min, T = 50 °C, and clarification time is 20 min to obtain the stripped solution and the stripped organic phase;

[0077] 5. Regeneration step: Regenerate the stripped organic phase obtained in step D with a 3 moL / L regenerant. The regeneration stage is 3 stages, O / A = 5:1, t = 2 min, regeneration temperature is the process temperature, and clarification time is 8 min to obtain the regenerated solution and the regenerated organic phase;

[0078] 6. High-temperature hydrolysis step: Add the stripped solution obtained in step D to pure water for high-temperature hydrolysis. The volume ratio of pure water to the stripped solution is 3:1, T = 85 °C, t = 8 h to obtain beryllium hydroxide;

[0079] 7. Calcination step: Calcinate the beryllium hydroxide obtained in step G, T = 940 °C, t = 2 h to obtain a high-purity beryllium oxide product.

[0080] Through the extraction and separation of the beryllium sulfate solution containing impurities and the preparation, a high-purity beryllium oxide product with a purity of 99.62% is obtained. The extraction rate and stripping rate of beryllium reach 99.28% and 99.31% respectively. However, the slag rate of the pretreatment slag is 38% of the slag rates of conventional bauxite slag and iron slag, and the total recovery rate of beryllium is only 86%. Obviously, the increase in slag rate leads to the decrease in beryllium recovery rate, and the slag contains obvious soluble beryllium and belongs to hazardous waste slag.

[0081] Example 2

[0082] The mass concentrations of the main components of the solution containing beryllium sulfate are (g / L) BeO 2.49, Fe 2.48, Al 8.17, F 19.41, SiO2 0.26. It includes the following steps:

[0083] 1. Pretreatment step: Turn on the stirring intensity of the beryllium sulfate solution tank to 450 revolutions per minute. While heating up to 85 °C, adjust the pH to 4.5 with liquid caustic soda. After reacting for 40 minutes, introduce air to initially remove iron. After reacting for 120 minutes, reduce the stirring intensity to 150 revolutions per minute. Then add 20% bone glue solution at mass concentrations of 5, 20, and 35 mL / L. Before filtration, add activated carbon at a mass concentration of 4 g / L, and filter and clarify for 25 hours. The mass concentration of the solid content in the clarified pretreatment liquid is 15 mg / L. Among them, after adding the 35 mL / L bone glue solution, there are a large number of dot-like local gels, making it impossible to filter. Therefore, only continue to process other groups.

[0084] 2. Be extraction step: In the prepared organic phase, di(2-ethylhexyl) phosphate: isopentanol: 260# solvent oil = 30:12:58. Perform Be extraction on the static pretreatment liquid obtained in step A in a box-type mixer-settler. The extraction stage is 6 stages, O / A = 1:3, extraction time = 6 minutes, extraction temperature is the process temperature, and clarification time is 8 minutes to obtain the raffinate and the loaded organic phase.

[0085] 3. Pickling step: Mix the loaded organic phase obtained in step B with a pickling agent of 5% oxalic acid + 4 g / L NaHSO3 for pickling. The pickling stage is 3 stages, O / A = 2:1, pickling time = 3 minutes, pickling temperature is the process temperature, and clarification time is 5 minutes to obtain the pickled liquid after pickling and the pickled organic phase.

[0086] 4. Stripping step: Perform stripping on the pickled organic phase obtained in step C with a 5 moL / L potassium hydroxide stripping agent. The stripping stage is 5 stages, O / A = 2:1, t = 10 minutes, T = 52 °C, and clarification time is 16 minutes to obtain the stripped liquid after stripping and the stripped organic phase.

[0087] 5. Regeneration step: Regenerate the stripped organic phase obtained in step D with a 2.5 moL / L regenerant. The regeneration stage is 4 stages, O / A = 3:1, t = 5 minutes, regeneration temperature is the process temperature, and clarification time is 6 minutes to obtain the regenerated liquid after regeneration and the regenerated organic phase.

[0088] 6. High-temperature hydrolysis step: Add the stripped liquid obtained in step D to pure water for high-temperature hydrolysis. The volume ratio of pure water to the stripped liquid is 6:1, T = 90 °C, t = 6 hours to obtain beryllium hydroxide.

[0089] 7. Calcination step: Calcinate the beryllium hydroxide obtained in step G, T = 900 °C, t = 4 hours to obtain a high-purity beryllium oxide product.

[0090] Through the extraction and separation of the beryllium sulfate solution containing impurities, a high-purity beryllium oxide product with a purity of 99.62% was prepared from the 20 mL / L bone glue solution group. The extraction rate and stripping rate of beryllium reached 99.24% and 99.18% respectively. The slag rate of the pretreatment slag was 27% of the slag rates of conventional bauxite slag and iron slag, and the total recovery rate of beryllium reached 97.31%.

[0091] While a beryllium oxide product with a purity of 97.83% was prepared from the 5 mL / L bone glue solution group. The extraction rate and stripping rate of beryllium reached 94.61% and 99.36% respectively. The slag rate of the pretreatment slag was 28% of the slag rates of conventional bauxite slag and iron slag, and the total recovery rate of beryllium reached 88.15%.

[0092] When the bone glue solution was 35 mL / L, the solution could not be filtered and subsequent treatment could not be carried out.

[0093] Comparative Example 3

[0094] The mass concentrations of the main components of the beryllium sulfate solution are (g / L): BeO 2.49, Fe 2.48, Al 8.17, F 19.41, SiO2 0.26. It includes the following steps:

[0095] 1. Pretreatment step: Turn on the stirring intensity of the beryllium sulfate solution tank to 450 revolutions per minute. While raising the temperature to 85 °C, adjust the pH to 4.5 with liquid caustic soda. After reacting for 40 minutes, then introduce air for preliminary iron removal. After reacting for 120 minutes, reduce the stirring intensity to 150 revolutions per minute. Then add 20% bone glue solution at a mass concentration of 20 mL / L. Before filtration, add activated carbon at a mass concentration of 4 g / L. Filter and clarify for 25 hours. The mass concentration of the solid content in the clarified pretreatment liquid is 15 mg / L; after adding 35 mL / L of bone glue solution, there are a large number of dot-like local gels and it cannot be filtered. Therefore, only other groups are continued to be processed.

[0096] 2. Be extraction step: In the prepared organic phase, bis(2-ethylhexyl) phosphate: isoamyl alcohol: 260# solvent oil = 40:15:45 or bis(2-ethylhexyl) phosphate: 260# solvent oil = 20:5:75. Perform Be extraction on the static pretreatment liquid obtained in step A in a box-type mixer-settler. The extraction stage is 6 stages, O / A = 1:3, extraction time = 6 minutes, extraction temperature is the process temperature, and clarification time is 8 minutes to obtain a raffinate and a loaded organic phase;

[0097] 3. Pickling step: Mix the loaded organic phase obtained in step B with an acid pickling agent of 5% oxalic acid + 4 g / L NaHSO3 for pickling. The pickling stage is 3 stages, O / A = 2:1, pickling time = 3 minutes, pickling temperature is the process temperature, and clarification time is 5 minutes to obtain a pickled post-liquid and a pickled post-organic phase;

[0098] 4. Stripping step: The pickled organic phase obtained in step C is stripped with a 5 mol / L potassium hydroxide stripping agent. The number of stripping stages is 5, O / A = 2:1, t = 10 min, T = 52 °C, and the clarification time is 16 min to obtain the stripped liquid and the stripped organic phase;

[0099] 5. Regeneration step: The stripped organic phase obtained in step D is regenerated with a 2.5 mol / L regenerant. The number of regeneration stages is 4, O / A = 3:1, t = 5 min, the regeneration temperature is the process temperature, and the clarification time is 6 min to obtain the regenerated liquid and the regenerated organic phase;

[0100] 6. High-temperature hydrolysis step: The stripped liquid obtained in step D is added to pure water for high-temperature hydrolysis. The volume ratio of pure water to the stripped liquid is 6:1, T = 90 °C, t = 6 h to obtain beryllium hydroxide;

[0101] 7. Calcination step: The beryllium hydroxide obtained in step G is calcined, T = 900 °C, t = 4 h to obtain a high-purity beryllium oxide product.

[0102] Through the extraction and separation of the beryllium sulfate solution containing impurities, high-purity beryllium oxide products with purities of 99.55% and 99.70% are respectively prepared. The BeO content in the raffinate is 0.74 - 0.80 g / L. The extraction rate and stripping rate of beryllium reach 70.28% and 98.73% respectively. The slag rate of the pretreatment slag is 25 - 27% of the slag rates of conventional bauxite slag and iron slag. The total recovery rate of beryllium is 68.81 - 71.12%. Therefore, when the composition of the extraction organic phase is different and the relevant ratios are not within the range, the BeO content in the raffinate increases and the recovery rate decreases.

[0103] Example 4

[0104] The mass concentrations of the main components of the beryllium sulfate solution are (g / L) BeO 12.51, Fe 1.52, Al 14.23, F 31.63, SiO2 0.52. It includes the following steps:

[0105] 1. Pretreatment step: The stirring intensity of the beryllium sulfate solution tank is turned on to 350 revolutions per minute. While heating up to 80 °C, the pH is adjusted to 4.8 with liquid caustic soda. After reacting for 45 min, air is then introduced for preliminary iron removal. After reacting for 180 min, the stirring intensity is reduced to 180 revolutions per minute. Then, a 15% bone glue solution is added at a mass concentration of 10 mL / L. Before filtration, activated carbon is added at a mass concentration of 2 g / L. After filtration and clarification for 16 h, the mass concentration of the solid content in the clarified pretreatment liquid is 20 mg / L;

[0106] 2. Be extraction step: In the prepared organic phase, tributyl phosphate : isoamyl alcohol : sulfonated kerosene = 25 : 15 : 60. The static pretreatment liquid obtained in step A is subjected to Be extraction in a box-type mixer-settler. The extraction stage number is 8, O / A = 1 : 0.5, extraction time = 4 min, extraction temperature is the process temperature, and clarification time is 6 min, obtaining raffinate and loaded organic phase;

[0107] 3. Pickling step: The loaded organic phase obtained in step B is mixed with a pickling agent of 3% oxalic acid + 5 g / L KHSO3 for pickling. The pickling stage number is 4, O / A = 1 : 1, pickling time = 1 min, pickling temperature is the process temperature, and clarification time is 4 min, obtaining pickled liquid and pickled organic phase;

[0108] 4. Stripping step: The pickled organic phase obtained in step C is stripped with a 3.5 moL / L sodium hydroxide stripping agent. The stripping stage number is 6, O / A = 1 : 1, t = 4 min, T = 56 °C, and clarification time is 12 min, obtaining stripped liquid and stripped organic phase;

[0109] 5. Regeneration step: The stripped organic phase obtained in step D is regenerated with a 2 moL / L regenerant. The regeneration stage number is 4, O / A = 1 : 1, t = 8 min, regeneration temperature is the process temperature, and clarification time is 4 min, obtaining regenerated liquid and regenerated organic phase;

[0110] 6. High-temperature hydrolysis step: The stripped liquid obtained in step D is added to pure water for high-temperature hydrolysis. The volume ratio of pure water to the stripped liquid is 8 : 1, T = 94 °C, t = 4 h, obtaining beryllium hydroxide;

[0111] 7. Calcination step: The beryllium hydroxide obtained in step G is calcined, T = 850 °C, t = 5 h, obtaining high-purity beryllium oxide product.

[0112] Through the extraction separation and preparation of the impure beryllium sulfate solution this time, a high-purity beryllium oxide product with 99.67% purity is obtained. The extraction rate and stripping rate of beryllium reach 99.15% and 99.21% respectively. The slag rate of the pretreatment slag is 30% of the slag rates of conventional bauxite slag and iron slag, and the total recovery rate of beryllium reaches 97.21%.

[0113] Example 5

[0114] The mass concentrations of the main components of the beryllium sulfate solution are (g / L) BeO 12.51, Fe 1.52, Al 14.23, F 31.63, SiO2 0.52. It includes the following steps:

[0115] 1. Pretreatment step: Turn on the stirring intensity of the beryllium sulfate solution tank to 350 revolutions per minute. While heating up to 80 °C, adjust the pH to 4.8 with liquid caustic soda. After reacting for 45 minutes, introduce air to preliminarily remove iron. After reacting for 180 minutes, reduce the stirring intensity to 180 revolutions per minute. Then add a 15% bone glue solution at a mass concentration of 10 mL / L. Before filtration, add activated carbon at a mass concentration of 2 g / L. Filter and clarify for 16 hours. The mass concentration of the solid content in the clarified pretreatment liquid is 20 mg / L.

[0116] 2. Be extraction step: In the prepared organic phase, tributyl phosphate: isoamyl alcohol: sulfonated kerosene = 25:15:60. Perform Be extraction on the static pretreatment liquid obtained in step A in a box-type mixer-settler. The extraction stage is 8, O / A = 1:0.5, extraction time = 4 minutes, extraction temperature is the process temperature, and clarification time is 6 minutes to obtain the raffinate and the loaded organic phase.

[0117] 3. Pickling step: Mix the loaded organic phase obtained in step B with a pickling agent of 3% oxalic acid + 2 g / L KHSO3 for pickling, and then with a pickling agent of 2% oxalic acid + 4 g / L KHSO3 for pickling. The pickling stage is 4, O / A = 1:1, pickling time = 1 minute, pickling temperature is the process temperature, and clarification time is 4 minutes to obtain the pickled liquid after pickling and the pickled organic phase after pickling.

[0118] 4. Stripping step: Perform stripping on the pickled organic phase obtained in step C with a 3.5 moL / L sodium hydroxide stripping agent. The stripping stage is 6, O / A = 1:1, t = 4 minutes, T = 56 °C, and clarification time is 12 minutes to obtain the stripped liquid after stripping and the stripped organic phase after stripping.

[0119] 5. Regeneration step: Regenerate the stripped organic phase obtained in step D with a 2 moL / L regenerant. The regeneration stage is 4, O / A = 1:1, t = 8 minutes, regeneration temperature is the process temperature, and clarification time is 4 minutes to obtain the regenerated liquid after regeneration and the regenerated organic phase after regeneration.

[0120] 6. High-temperature hydrolysis step: Add the stripped liquid obtained in step D to pure water for high-temperature hydrolysis. The volume ratio of pure water to the stripped liquid is 8:1, T = 94 °C, t = 4 hours to obtain beryllium hydroxide.

[0121] 7. Calcination step: Calcinate the beryllium hydroxide obtained in step G, T = 850 °C, t = 5 hours to obtain a high-purity beryllium oxide product.

[0122] By subjecting the beryllium sulfate-containing solution to extraction separation, intermediate beryllium oxide materials with purities of 91.05% and 90.88% were prepared. After further purification through additional purification processes, high-purity beryllium oxide products were obtained. The extraction rate and stripping rate of beryllium reached 98.85 - 99.23% and 97.35 - 97.68% respectively. The slag rate of the pretreatment slag was 25 - 28% of the slag rates of conventional bauxite slag and iron slag. The total recovery rate of beryllium reached 90.43 - 91.02%. Therefore, the total recovery rate of beryllium decreased, and another purification process was required, resulting in a significant increase in production cost and a decrease in efficiency.

[0123] Example 6

[0124] The mass concentrations of the main components of the beryllium sulfate-containing solution are (g / L): BeO 12.51, Fe 1.52, Al 14.23, F 31.63, SiO2 0.52. It includes the following steps:

[0125] 1. Pretreatment step: The stirring intensity of the beryllium sulfate solution tank is set to 350 revolutions per minute. While heating up to 80°C, the pH is adjusted to 4.8 using liquid caustic soda. After reacting for 45 minutes, air is introduced for preliminary iron removal. After reacting for 180 minutes, the stirring intensity is reduced to 180 revolutions per minute. Then, a 15% bone glue solution is added at a mass concentration of 10 mL / L. Before filtration, activated carbon is added at a mass concentration of 2 g / L. After filtering and clarifying for 16 hours, the mass concentration of the solid content in the clarified pretreatment liquid is 20 mg / L.

[0126] 2. Be extraction step: In the prepared organic phase, tributyl phosphate: isoamyl alcohol: sulfonated kerosene = 25:15:60. The static pretreatment liquid obtained in step A is subjected to Be extraction in a box-type mixer-settler. The extraction stage number is 8, O / A = 1:0.5, the extraction time = 4 minutes, the extraction temperature is the process temperature, and the clarification time is 6 minutes, obtaining a raffinate and a loaded organic phase.

[0127] 3. Pickling step: The loaded organic phase obtained in step B is mixed with a pickling agent of 3% oxalic acid + 5 g / L KHSO3 for pickling. The pickling stage number is 4, O / A = 1:1, the pickling time = 1 minute, the pickling temperature is the process temperature, and the clarification time is 4 minutes, obtaining a pickled solution and a pickled organic phase.

[0128] 4. Stripping step: The pickled organic phase obtained in step C is stripped with a 3.5 moL / L sodium hydroxide stripping agent. The stripping stage number is 6, O / A = 1:1, t = 4 minutes, T = 56°C, and the clarification time is 12 minutes, obtaining a stripped solution and a stripped organic phase.

[0129] 5. Regeneration step: The organic phase after back extraction obtained in step D is regenerated with a 2 mol / L regenerant. The number of regeneration stages is 4, O / A = 1:1, t = 8 min, the regeneration temperature is the process temperature, and the clarification time is 4 min to obtain the regenerated liquid and the regenerated organic phase.

[0130] 6. High-temperature hydrolysis step: The back-extracted liquid obtained in step D is added to pure water for high-temperature hydrolysis. The volume ratio of pure water to the back-extracted liquid is 8:1, T is 82, 94, 98 °C, t = 4 h to obtain beryllium hydroxide.

[0131] 7. Calcination step: The beryllium hydroxide obtained in step G is calcined, T = 850 °C, t = 5 h to obtain a high-purity beryllium oxide product.

[0132] Through the extraction and separation of the beryllium sulfate solution containing impurities and hydrolysis under the high-temperature hydrolysis conditions of 94 °C, a high-purity beryllium oxide product with a purity of 99.67% is prepared. The extraction rate and back-extraction rate of beryllium reach 99.15% and 99.21% respectively. The slag rate of the pretreatment slag is 30% of the slag rates of conventional bauxite slag and iron slag, and the total recovery rate of beryllium reaches 97.21%. When the hydrolysis temperature is 82 °C, the beryllium content in the hydrolyzed liquid is 0.72 g / L, and the hydrolysis is incomplete. Although a high-purity beryllium oxide product can be obtained, and the extraction rate and back-extraction rate of beryllium both exceed 99%, the total recovery rate of beryllium drops by more than 3%. When the hydrolysis temperature is 98 °C, the hydrolysis rate of beryllium reaches the enterprise standard, but due to a large amount of water evaporation, a large amount of impurities such as Ca and Mg enter the hydrolyzed beryllium hydroxide, resulting in an industrial-grade beryllium oxide product.

[0133] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An extraction and separation method for a high-fluoride beryllium sulfate solution, characterized in that, It includes the following steps: S1. Pretreatment: Adjust the pH of the beryllium sulfate solution with high fluorine content to 4.0 - 4.8, heat it up to 80 - 90 °C and react for 30 - 45 min. Then introduce air, react for 60 - 180 min, add bone glue solution at a mass concentration of 10 - 25 mL / L, add activated carbon, filter to obtain a pretreated solution, and let it stand for clarification; S2. Extraction: Extract the pretreated solution after standing for clarification. In the extraction, the volume ratio of the oil phase to the water phase is 1:0.5 - 5, and the extraction time is 4 - 8 min to obtain a raffinate and a loaded organic phase; the oil phase refers to a mixed organic phase of an extractant, a diluent, and a synergistic extractant; S3. Acid washing: Acid wash the loaded organic phase. In the acid washing, the volume ratio of the oil phase to the acid washing agent is 1 - 4:1, and the acid washing time is 1 - 5 min to obtain an acid-washed solution and an acid-washed organic phase; S4. Back extraction: Back extract the acid-washed organic phase. In the back extraction, the volume ratio of the oil phase to the back extractant is 1 - 3:1, the back extraction time is 4 - 15 min, and the back extraction temperature is 50 - 56 °C to obtain a back-extracted solution and a back-extracted organic phase; S5. High-temperature hydrolysis: Add the back-extracted solution obtained in step S4 to pure water for high-temperature hydrolysis. The volume ratio of pure water to the back-extracted solution is 3 - 8:1, the hydrolysis temperature is 85 - 94 °C, and the high-temperature hydrolysis time is 4 - 8 h to obtain beryllium hydroxide; S6. Calcination: Calcinate beryllium hydroxide at 850 - 940 °C for 2 - 5 h to obtain beryllium oxide product; The beryllium sulfate solution with high fluorine content contains: Fe 1.3 - 3.5 g / L, Al 8.0 - 15.0 g / L, F 10.0 - 35.0 g / L, SiO2 0.2 - 0.5 g / L; The mass percentage concentration of the bone glue solution is 15 - 25%; The acid washing agent is a mixed solution of oxalic acid and a sulfite or bisulfite; in step S1, use sodium base to adjust the pH of the beryllium sulfate solution with high fluorine content to 4.0 - 4.8, and use the impurities F and Al in the beryllium sulfate solution and Na in the sodium base to carry out a cryolite preparation reaction to generate sodium hexafluoroaluminate particles; the sodium base is sodium hydroxide, sodium bicarbonate, or sodium carbonate.

2. The extraction and separation method according to claim 1, wherein The mass concentration of the sodium base is 25 - 30%.

3. The extraction and separation method according to claim 1, wherein The amount of air introduced is 3 - 12 times the theoretical amount of oxygen required to oxidize divalent iron to trivalent iron.

4. The extraction and separation method according to claim 1, characterized in that, The addition amount of activated carbon is 2 - 5 g / L.

5. The extraction and separation method according to claim 1, characterized in that, In step S2, the volume percentage concentrations of the extractant, synergistic extractant, and diluent in the oil phase are 25 - 35%:10 - 15%:50 - 65% respectively; the extractant is one or a mixture of two of 2-ethylhexyl phosphoric acid, bis(2-ethylhexyl) phosphate, and tributyl phosphate, the diluent is sulfonated kerosene or 260# solvent oil, and the synergistic extractant is isoamyl alcohol.

6. The extraction and separation method according to claim 1, characterized in that, The acid washing agent is a mixed solution of oxalic acid with a mass percentage concentration of 3 - 7% and a soluble sulfite or bisulfite with a mass concentration of 3 - 5 g / L.

7. The extraction and separation method according to claim 1, characterized in that, The back extractant refers to a sodium hydroxide or potassium hydroxide solution with a mass molar concentration of 3.5 - 7 moL / L.

8. The extraction and separation method according to any one of claims 1-7, characterized in that, The extraction and separation method further includes regenerating the organic phase after back-extraction using a regenerant; the regenerant is a sulfuric acid solution with a mass molar concentration of 2 - 3 moL / L, the target for regeneration is the organic phase after back-extraction, the number of regeneration stages is 3 - 4, the volume ratio of the oil phase to the regenerant in each stage of regeneration is 1 - 5:1, and the regeneration time is 2 - 8 min.

9. The extraction and separation method according to any one of claims 1-7, characterized in that The extraction and separation method further includes a clarification step.

10. The extraction and separation method according to any one of claims 1-7, characterized in that, A clarification step is designed between the last extraction stage and the pickling stage, between the last pickling stage and the back-extraction stage, and between the last back-extraction stage and the regeneration stage, and the clarification time is 15 - 30 min.

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