Process for the separation and purification of beryllium from a beryllium-containing solution

Abstract

This invention relates to the field of hydrometallurgical technology and discloses a method for separating and purifying beryllium in beryllium-containing solutions. It aims to solve the problems of severe iron-aluminum co-extraction, easy precipitation during back-extraction, the need for high-temperature back-extraction, high oxalic acid consumption, complex process flow, and high energy consumption and cost in the existing P204 extraction system for purifying beryllium-containing solutions. This invention pre-treats the iron- and beryllium-containing solution with oxidation, adjusts the pH, and then uses ketoxime, amine, or carboxylic acid extractants for deep iron removal, which can remove more than 99% of iron impurities. The pH of the iron-removed solution is then adjusted, and beryllium is extracted using the P204 system. After washing with low-concentration oxalic acid, back-extraction with room-temperature alkaline solution, and regeneration of the organic phase, deep separation of beryllium from iron and aluminum impurities is achieved.

Description

Technical Field

[0001] This invention relates to the field of hydrometallurgical technology, and more specifically, to a method for separating and purifying beryllium from a beryllium-containing solution. Background Technology

[0002] Beryllium is a rare metal that combines lightweight and high strength, making it an indispensable strategic raw material in aerospace, nuclear industry, and high-end electronics. The purity of the product and the stability of the extraction and purification process determine the application value and scope of beryllium materials. Currently, industrial purification of beryllium from acidic beryllium-containing solutions mainly employs two processes: chemical precipitation and solvent extraction. The P204 single extraction system, represented by Minmetals Beryllium Industry, is the most widely used. This system uses P204, alcohol, and sulfonated kerosene as the organic phase, achieving beryllium separation and extraction through multi-stage extraction, high-concentration oxalic acid washing, and high-temperature strong alkali back-extraction. However, in actual industrial production, existing traditional processes generally suffer from a series of technical defects that are difficult to fundamentally solve, such as poor adaptability, low selectivity, high energy consumption, large reagent consumption, and significant environmental pressure.

[0003] First, there are problems with traditional hydrolysis precipitation for iron removal. Traditional acidic beryllium-containing solutions often employ hydrolysis precipitation for pre-iron removal, but this method is extremely unsuitable for high-residual-acid leachate systems: the high residual acidity of the feed solution necessitates the addition of large amounts of alkali to adjust the pH, resulting in high reagent consumption and significantly increased production costs; during iron removal, beryllium and iron readily co-precipitate, with a large amount of beryllium being lost, directly reducing the beryllium recovery rate; the generated ferric hydroxide is a colloidal precipitate with fine particles and poor filtration performance, easily causing blockage, malfunction, or even damage to plate and frame filter presses, severely impacting operational efficiency and equipment lifespan; problems such as feed solution mixing and residual ferrous ions are prone to occur, resulting in excessive iron content in the liquid after iron removal, failing to meet the purity requirements of high-end beryllium products; iron-containing beryllium slag is hazardous waste, and the beryllium it contains is difficult to recover, leading to high costs for storage, transportation, and harmless disposal, posing significant environmental risks and burdens.

[0004] Secondly, existing technologies have reported the use of the P204-alcohol-kerosene system for beryllium extraction. For example, CN103556186B discloses a process route of P204 extraction, oxalic acid washing, and NaOH back-extraction. However, the oxalic acid concentration and back-extraction conditions still have room for optimization. The current mainstream P204 extraction process still has the following inherent defects: Industrially, the P204 extraction system is used to extract beryllium to avoid the drawbacks of precipitation methods. However, this process does not control iron at the source. The core problems are concentrated in poor extraction selectivity, harsh back-extraction conditions, high reagent consumption, and a lengthy process. It has strong extraction capabilities for impurities such as iron and aluminum, but a large number of impurities enter the organic phase simultaneously with beryllium. Conventional washing is insufficient for deep iron removal, and iron in the back-extraction stage easily reacts with alkaline solution to form hydroxide precipitates, causing turbidity in the back-extraction solution, difficulty in phase separation, and significant beryllium entrainment loss, making it difficult to guarantee product purity. To alleviate the back-extraction precipitation problem, back-extraction must be carried out at high temperatures, resulting in huge heat energy consumption. At the same time, the synergistic effect of high temperature and high concentration of sodium hydroxide significantly aggravates the corrosion of extraction equipment, shortens equipment life, and increases operation and maintenance costs. High-concentration oxalic acid washing is required for impurity removal, but oxalic acid does not fully participate in the reaction, resulting in low reagent utilization. Washing wastewater cannot be reused and is directly discharged, increasing the wastewater treatment load and environmental disposal costs. To compensate for insufficient selectivity and stability, multi-stage extraction, washing, back-extraction, and regeneration units are required, resulting in a large number of equipment, long process, large material flow losses, low production efficiency, and difficulty in adapting to large-scale continuous production. The O / A ratio of each process in extraction, washing, and back-extraction is unreasonable, resulting in large consumption of organic phase, washing liquid, and back-extraction agent, low resource utilization, and further increasing production costs.

[0005] Although those skilled in the art have conducted numerous optimization studies on the P204 system, such as adding TBP to form a composite extraction system and using a novel extraction system combining Cyanex 272 and TBP, none of these efforts have achieved a fundamental breakthrough. Some solutions only slightly improve the beryllium extraction rate, but further enhance the extraction capacity of impurities, resulting in an increase in oxalic acid usage instead of a decrease. Some systems require saponification pretreatment, have a narrow applicable pH range, and are prone to producing flocculent precipitates. They still cannot solve the core technical bottlenecks such as iron co-extraction, high temperature requirements for back-extraction, easy precipitation during room temperature back-extraction, and high reagent consumption.

[0006] In summary, existing purification processes for acidic beryllium-containing solutions cannot simultaneously achieve efficient impurity removal, high beryllium yield, low energy consumption, low cost, and environmental friendliness. Developing a new extraction, separation, and purification method that can remove iron impurities at the source, achieve room-temperature precipitation-free back-extraction, deeply separate beryllium from iron and aluminum impurities, simplify the process, and reduce reagent energy consumption has become an urgent need to be addressed in the field of beryllium hydrometallurgy. Summary of the Invention

[0007] In view of the above problems, the purpose of this invention is to provide a method for separating and purifying beryllium in beryllium-containing solutions, so as to solve the problems of severe iron-aluminum co-extraction, easy precipitation during back-extraction, high temperature back-extraction, large consumption of oxalic acid, complex process flow, high energy consumption and high cost in the process of purifying beryllium-containing solutions by existing P204 extraction system.

[0008] This invention provides a method for separating and purifying beryllium from a beryllium-containing solution, comprising: Adding an oxidant to a beryllium-containing aqueous phase to oxidize ferrous ions in the aqueous phase. The pH of the beryllium-containing aqueous phase after oxidation was adjusted to 0.1-2 using acid-base agents; Iron extraction was performed on the conditioned beryllium-containing aqueous phase using an iron extractant, an iron extractant modifier, and an iron extractant diluent to obtain an iron-loaded organic phase and an iron-free beryllium-containing aqueous phase. The beryllium ions in the supported iron organic phase were washed with a detergent. The washed aqueous phase containing beryllium ions is returned to the conditioning process, and the washed iron-loaded organic phase is back-extracted to obtain a high-ferrous aqueous phase. The high-speed iron aqueous phase is sent into the iron recovery system, and the empty organic phase containing trace iron ions is regenerated and the regenerated organic phase is returned to the iron extraction process. The pH of the iron-free beryllium-containing aqueous phase is adjusted to 1-5, wherein the beryllium concentration is ≤5.0 g / L; The conditioned iron-free beryllium-containing aqueous phase was subjected to beryllium extraction using a beryllium extractant, a beryllium extraction modifier, and a beryllium extraction diluent to obtain a beryllium-loaded organic phase and a raffinate aqueous phase. Wash away impurity ions from the supported beryllium organic phase; A back-extraction agent was used to back-extract the loaded beryllium organic phase after removing impurity ions, resulting in a beryllium back-extractant and an empty organic phase containing trace amounts of beryllium ions. An organic phase containing trace amounts of beryllium ions is regenerated using a regenerating agent, and the regenerated organic phase is then returned to the beryllium extraction process.

[0009] Alternatively, in the process of adding an oxidant to a beryllium-containing aqueous phase to oxidize ferrous ions in the aqueous phase, the oxidation conditions are: temperature 15~80℃, oxidation time 1min~72h, and the amount of oxidant added is 2 times or more of the ferrous ions.

[0010] Alternatively, the acid or base agent may be selected from any one of sodium hydroxide, sodium carbonate, sulfuric acid, hydrochloric acid, or nitric acid.

[0011] Alternatively, an alternative approach is to use an iron extractant, an iron extractant modifier, and an iron extractant diluent to perform iron extraction on the conditioned beryllium-containing aqueous phase to obtain an iron-loaded organic phase and an iron-free beryllium-containing aqueous phase. The ratio of the iron extractant, the iron extract modifier, and the iron extract diluent is 5-40%, 5-20%, and 90-40%, respectively. The iron extractant is selected from any one of Lix54, Lix63, Lix64N, Lix984, N910, N1923, Primene JM-T, N235, N503, TIOA, CA12, Versatic 10, naphthenic acid 70, naphthenic acid 75, and naphthenic acid 80. The iron extraction modifier is selected from any one of isooctanol, isoamyl alcohol, isodecyl alcohol, isobutanol, n-octanol, n-decyl alcohol, n-butanol, sec-octanol, dodecanol, and β-branched primary alcohols; The iron extraction diluent is selected from any one of sulfonated kerosene, isoalkanes, aviation kerosene, and dodecane; The iron extraction conditions are: O / A = 1:1~1:10, extraction time 3min-30min, temperature 25~60℃, and number of stages 2~6.

[0012] Alternatively, in the process of washing the beryllium ions in the supported iron organic phase with a detergent, the detergent is selected from any one of sulfuric acid solution, hydrochloric acid solution, or nitric acid solution with a pH value of 0.2 to 2.0. The washing conditions are: O / A = 10:1~2:1, single-stage reaction time 3~10min, temperature 25~60℃, and washing stages 2~6.

[0013] Alternatively, in the process of back-extracting the washed iron-loaded organic phase to obtain the high-iron aqueous phase, the back-extraction agent used in the back-extraction process is a mixed solution of 0.1~3M hydrochloric acid or nitric acid and 0.1wt%~5wt% sodium metabisulfite or sodium sulfite. The back-extraction conditions are: O / A = 10:1~2:1, single-stage reaction time 3~20 min, temperature 25~60℃, and 2~6 back-extraction stages.

[0014] Alternatively, in the process of regenerating an empty organic phase containing trace amounts of iron ions, the regenerator used in the regeneration process can be selected from any one of pure water, dilute sulfuric acid, dilute hydrochloric acid, or dilute nitric acid. The regeneration conditions are: O / A = 1:1~10:1, single-stage reaction time 3~10 min, temperature 25~55℃, and number of regeneration stages 2~6.

[0015] Alternatively, the pH of the iron-free beryllium-containing aqueous phase can be adjusted to 1-5 using sodium hydroxide, sodium carbonate, or sulfuric acid.

[0016] Alternatively, in the process of beryllium extraction of the conditioned iron-free beryllium-containing aqueous phase using beryllium extractant, beryllium extract modifier and beryllium extract diluent, the beryllium extractant is P204; The beryllium extraction modifier is selected from any one of isooctanol, isoamyl alcohol, isodecyl alcohol, isobutanol, n-octanol, n-decyl alcohol, n-butanol, sec-octanol, dodecanol, and β-branched primary alcohols; The beryllium extraction diluent is selected from any one of sulfonated kerosene, isoalkanes, aviation kerosene, and dodecane; The ratio of the beryllium extractant, the beryllium extract modifier, and the beryllium extract diluent is: 10%~40%, 0~20%, and 40%~90%, respectively. The beryllium extraction conditions are: O / A = 5:1~1:3, single-stage reaction time 5~60 min, temperature 15~45℃, and 2~6 stages of countercurrent extraction.

[0017] Alternatively, during the washing process of impurity ions in the supported beryllium organic phase, The detergent used in the washing process is any one of the following: 1%~5% oxalic acid solution, 0.01-2M hydroxyethylidene diphosphine solution, triethylenetetramine hexaacetic acid solution, or aqueous acetic acid solution; The washing conditions are: O / A = 15:1~2:1, single-stage reaction time 3~10 min, temperature 15~45℃, and washing stages 2~6.

[0018] Alternatively, in the process of back-extracting the supported beryllium organic phase to remove impurity ions using a back-extracting agent, the back-extracting agent is selected from any one of 1-5M sodium hydroxide, 1-6M sulfuric acid, or hydrochloric acid. The beryllium back-extraction conditions are: O / A = 15:1~2:1; single-stage reaction time 10~30 min; temperature 15~45℃; 2~6 stages of countercurrent extraction.

[0019] Alternatively, in the process of regenerating the empty organic phase containing trace amounts of beryllium ions using a regenerator, the regenerator is selected from any one of pure water, sodium hydroxide, potassium hydroxide, ammonia, sodium carbonate, and sodium bicarbonate solution. The regeneration conditions are: O / A = 40:1~5:1, single-stage reaction time 3~10 min, temperature 15~45℃; number of regeneration stages 2~6.

[0020] As can be seen from the above technical solution, the present invention provides a method for separating and purifying beryllium in a beryllium-containing solution. This method utilizes pre-extraction with ketoximes, amines, or carboxylic acids to deeply remove iron, thoroughly eliminating iron impurities at the source. This fundamentally solves the interference of iron on beryllium extraction and purification, achieving highly efficient and deep separation of beryllium from iron and aluminum impurities. Compared with the traditional P204 extraction process, it has the following significant technical advantages: (1) Pre-extraction can efficiently remove iron impurities, eliminate the problem of co-extraction of iron and beryllium, significantly improve the extraction accuracy and separation effect of beryllium, and avoid the problems of precipitation and entrainment caused by iron impurities in subsequent processes.

[0021] (2) Alkali back-extraction can be completed without high-temperature heating, the operating conditions are mild, and energy consumption is significantly reduced; at the same time, the formation of ferric hydroxide precipitate is avoided, the system is stable, the phase separation is fast and clear, the beryllium entrainment loss is reduced, and the beryllium direct recovery rate is improved.

[0022] (3) High-efficiency impurity removal can be achieved by using low-concentration oxalic acid washing, which greatly reduces the amount of oxalic acid used and the pressure of wastewater treatment; at the same time, process parameters are optimized, the number of extraction, washing and back-extraction stages is shortened, the process is simplified, and the equipment investment and operating costs are reduced.

[0023] (4) There is no phase change, precipitation, or emulsification throughout the process. The process is stable and reliable, and can continuously and stably produce high-purity beryllium products. It takes into account the purification effect, production efficiency and environmental protection, and is more suitable for large-scale industrial applications.

[0024] To achieve the foregoing and related objectives, one or more aspects of the invention include the features that will be described in detail below. The following description and accompanying drawings illustrate certain exemplary aspects of the invention. However, these aspects indicate only a few of the various ways in which the principles of the invention can be used. Furthermore, the invention is intended to encompass all such aspects and their equivalents. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a flowchart of a method for separating and purifying beryllium in a beryllium-containing solution according to an embodiment of the present invention. Detailed Implementation

[0027] In the following description, numerous specific details are set forth for illustrative purposes and to provide a thorough understanding of one or more embodiments. However, it will be apparent that these embodiments may also be implemented without these specific details. In other instances, well-known structures and devices are shown in block diagram form for ease of description of one or more embodiments.

[0028] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0029] This invention can be modified and has various embodiments, with specific embodiments illustrated in the accompanying drawings. However, this invention is not limited to this particular implementation and all modifications, equivalents, and substitutions falling within the spirit and technical scope of this invention are to be understood as included.

[0030] Ordinal terms such as "first," "second," etc., may be used to describe various constituent elements, but the constituent elements are not limited to these terms. The terms are used only to distinguish one constituent element from another. For example, without departing from the scope of the claims of this invention, a second constituent element may be named a first constituent element, and similarly, a first constituent element may be named a second constituent element. Terms and / or include combinations of multiple associated items or one of multiple associated items.

[0031] It should be understood that when referring to a constituent element being "connected" or "in contact" with other constituent elements, this includes not only cases where it is directly connected or in contact with other constituent elements, but also cases where other constituent elements exist between them. Conversely, when referring to a constituent element being "directly connected" or "directly in contact" with other constituent elements, it should be understood that no other constituent elements exist between them.

[0032] In response to the aforementioned problems in the existing P204 extraction system for purifying beryllium-containing solutions, such as severe iron-aluminum co-extraction, easy precipitation during back-extraction, the need for high-temperature back-extraction, high oxalic acid consumption, complex process flow, and high energy consumption and cost, this invention proposes a method to address these issues.

[0033] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0034] To illustrate the method for separating and purifying beryllium from a beryllium-containing solution provided by this invention, Figure 1A process flow diagram for separating and purifying beryllium from a beryllium-containing solution according to an embodiment of the present invention is shown.

[0035] like Figure 1 As shown, the present invention provides a method for separating and purifying beryllium from a beryllium-containing solution, comprising: An oxidant is added to a beryllium-containing aqueous phase to oxidize the ferrous ions in the aqueous phase; The pH of the beryllium-containing aqueous phase after oxidation was adjusted to 0.1-2 using acid-base agents; Iron extraction was performed on the conditioned beryllium-containing aqueous phase using an iron extractant, an iron extractant modifier, and an iron extractant diluent to obtain an iron-loaded organic phase and an iron-free beryllium-containing aqueous phase. The beryllium ions in the supported iron organic phase were washed with a detergent. The washed aqueous phase containing beryllium ions is returned to the conditioning process, and the washed iron-loaded organic phase is back-extracted to obtain a high-ferrous aqueous phase. The high-speed iron aqueous phase is sent into the iron recovery system, and the empty organic phase containing trace iron ions is regenerated and the regenerated organic phase is returned to the iron extraction process. The pH of the iron-free beryllium-containing aqueous phase is adjusted to 1-5, wherein the beryllium concentration is ≤5.0 g / L; The conditioned iron-free beryllium-containing aqueous phase was subjected to beryllium extraction using a beryllium extractant, a beryllium extraction modifier, and a beryllium extraction diluent to obtain a beryllium-loaded organic phase and a raffinate aqueous phase. Wash away impurity ions from the supported beryllium organic phase; A back-extraction agent was used to back-extract the loaded beryllium organic phase after removing impurity ions, resulting in a beryllium back-extractant and an empty organic phase containing trace amounts of beryllium ions. An organic phase containing trace amounts of beryllium ions is regenerated using a regenerating agent, and the regenerated organic phase is then returned to the beryllium extraction process.

[0036] In this invention, an extraction depth pre-iron removal step and a beryllium extraction process are set up. The extraction pre-iron removal step removes iron impurities at the source. With pH control, oxalic acid concentration and process parameter optimization, the traditional high-temperature back-extraction operation is completely eliminated, and alkaline back-extraction at room temperature is achieved without the generation of additional solids. At the same time, the number of process stages is simplified, oxalic acid consumption is reduced, and deep separation of beryllium from aluminum and iron impurities is achieved. It takes into account the extraction efficiency of beryllium, the back-extraction effect and the process economy, significantly reduces production energy consumption and reagent costs, and improves the stability and environmental protection of the process.

[0037] The pre-extraction iron removal process includes ferrous iron oxidation, pH adjustment of the aqueous phase, iron extraction, washing, back-extraction, and regeneration. Iron impurities are removed in advance to create a low-iron environment for subsequent beryllium extraction.

[0038] (1) Aqueous phase oxidation containing beryllium (pre-oxidation of ferrous iron)

[0039] Fe² in the feed solution + All oxidized to Fe³ + This creates the necessary valence state conditions for efficient extraction of iron using subsequent extractants. Oxidants such as sodium chlorate, hydrogen peroxide, potassium permanganate, or ozone are added to the beryllium-containing aqueous phase; the amount of oxidant added should be no less than twice the molar amount of ferrous ions to ensure complete oxidation; the temperature is controlled at 15~80℃, the stirring intensity is conventional, and the oxidation time is 1min~72h; after completion, the Fe²⁺ in the solution... + When the concentration drops below the detection limit, Fe³ + It is the main form of iron.

[0040] (2) Aqueous phase conditioning (precise pH control)

[0041] Adjust the pH of the feed solution to match the extractant's pH relative to Fe³⁺. + The optimal extraction range is determined while avoiding beryllium ion hydrolysis and precipitation. The pH of the feed solution is adjusted to 0.1~2.0 using sodium hydroxide, sodium carbonate, sulfuric acid, hydrochloric acid, or nitric acid; after conditioning, the feed solution directly enters the iron extraction process.

[0042] (3) Iron extraction process (selective iron extraction with extractant)

[0043] Using ketoximes, amines, or carboxylic acids as extractants for Fe³ + The high selectivity transfers iron impurities to the organic phase, resulting in an iron-free beryllium-containing aqueous phase. The iron extractant is selected from one of Lix54, Lix63, Lix64N, Lix984, N910, N1923, PrimeneJM-T, N235, N503, TIOA, CA12, Versatic10, or naphthenic acid 70 / 75 / 80; the iron extraction modifier is selected from one of isooctanol, isoamyl alcohol, isodecyl alcohol, isobutanol, n-octanol, n-decyl alcohol, n-butanol, sec-octanol, dodecanol, or β-branched primary alcohols; the iron extraction diluent is selected from sulfonated kerosene or isoalkanes; the ratio is 5-40% extractant, 5-20% modifier, and 40-90% diluent.

[0044] Extraction conditions: O / A ratio = 1:1~1:10; single-stage reaction time: 3~30 min; temperature: 25~60℃; number of stages: 2~6 stages of countercurrent extraction; post-extraction phase separation: the iron-loaded organic phase and the iron-free beryllium-containing aqueous phase are separated, and the aqueous phase directly enters the subsequent beryllium extraction process.

[0045] (4) Washing of the iron-loaded organic phase

[0046] The process removes trace amounts of beryllium ions entrained in the organic phase, reducing beryllium loss and preventing excessive beryllium content in the iron back-extraction solution. Washing agent: sulfuric acid, hydrochloric acid, or nitric acid solution with pH 0.2–2.0; O / A ratio: 10:1–2:1; single-stage reaction time: 3–10 min; temperature: 25–60 °C; number of stages: 2–6; after washing, the aqueous phase is returned to the conditioning process for recycling, while the iron-loaded organic phase enters the back-extraction process.

[0047] (5) Iron-loaded organic phase reverse extraction (preparation of high-ferric aqueous phase)

[0048] Fe³ in the organic phase + Back-extraction to the aqueous phase yields a high-ferric aqueous phase, enabling the recovery and utilization of iron impurities. Back-extraction agent: a mixed solution of 0.1~3M hydrochloric acid or nitric acid and 0.1wt%~5wt% sodium metabisulfite or sodium sulfite, which can simultaneously remove Fe³⁺. + Reduced to Fe² + This facilitates subsequent iron recovery. The back-extraction conditions are: relative O / A ratio: 10:1~2:1; single-stage reaction time: 3~20min; temperature: 25~60℃; number of stages: 2~6. After phase separation, a high-iron aqueous phase is obtained and sent to the iron recovery system, while the unloaded organic phase enters the regeneration process.

[0049] (6) Regeneration of unloaded organic phase (organic phase recycling)

[0050] This process removes trace amounts of residual iron ions and impurities from the organic phase, restores the extractant's performance, and achieves a closed-loop recycling of the organic phase. Regenerators include pure water, dilute sulfuric acid, dilute hydrochloric acid, or dilute nitric acid. Regeneration conditions are: O / A ratio 1:1~10:1; single-stage reaction time 3~10 min; temperature 25~55℃; number of stages 2~6. The regenerated organic phase is returned to the iron extraction process for reuse, completing the closed-loop pre-iron removal process.

[0051] Beryllium extraction process (optimization of P204 extraction system based on iron-free feed solution)

[0052] Using the iron-free beryllium-containing aqueous phase obtained from the pre-removal iron process as raw material, beryllium is enriched and purified through conditioning, extraction, washing, back-extraction, and regeneration processes, without the need for high-temperature operation throughout the entire process.

[0053] (1) Iron-free beryllium-containing aqueous conditioning

[0054] Adjust the pH and beryllium concentration of the feed solution to suit the extraction conditions of P204 extractant and avoid beryllium hydrolysis. Adjust the pH to 1.0~5.0 (preferably 1.8~3.0) using sodium hydroxide, sodium carbonate, or sulfuric acid; adjust the beryllium concentration to ≤5.0 g / L; after conditioning, the feed solution enters the beryllium extraction process.

[0055] (2) Beryllium extraction process (P204 Selective beryllium extraction)

[0056] Utilizing the high selectivity of P204 extractant for beryllium, beryllium ions are transferred to the organic phase for deep separation from impurities such as aluminum. Extractant: P204; Modifier: one of isooctanol, isoamyl alcohol, isodecyl alcohol, isobutanol, n-octanol, n-decyl alcohol, n-butanol, sec-octanol, dodecyl alcohol, or β-branched primary alcohol; Diluent: sulfonated kerosene, isoalkanes, aviation kerosene, dodecane, etc.; Ratio: extractant 10%~40%, modifier 0~20%, diluent 40%~90%.

[0057] Extraction conditions are: O / A ratio 5:1 to 1:3; single-stage reaction time 5 to 60 min, optional 20 to 40 min; temperature 15 to 45℃; number of stages: 2 to 6 stages of countercurrent extraction; after phase separation, the loaded beryllium organic phase enters the washing process, and the raffinate aqueous phase is discharged or returned to the system.

[0058] (3) Washing of the supported beryllium organic phase

[0059] The process removes aluminum and other impurity ions entrained in the organic phase, reducing the impurity content in the subsequent back-extraction solution and decreasing the amount of oxalic acid used. The washing agent is a 1%–5% oxalic acid solution (significantly lower concentration than the high-concentration oxalic acid used in traditional processes, greatly reducing reagent consumption). Alternatively, any one of the following can be used: 0.01–2M hydroxyethylidene diphosphine solution, triethylenetetraminehexaacetic acid solution, or aqueous acetic acid solution. The ratio of O / A is 15:1–2:1; single-stage reaction time is 3–10 min; temperature is 15–45℃; number of stages is 2–6. After washing, the aqueous phase is returned to the system for further processing, and the beryllium-loaded organic phase enters the back-extraction process.

[0060] (4) Supported beryllium organic back-extraction (no precipitation back-extraction at room temperature)

[0061] Under ambient temperature conditions, beryllium ions in the organic phase are back-extracted to the aqueous phase to obtain a high-purity beryllium back-extractant, free from iron impurities and without the formation of hydroxide precipitates. The back-extracting agent is any one of 1-5M sodium hydroxide solution, 1-6M sulfuric acid, or hydrochloric acid; the O / A ratio is 15:1-2:1; the single-stage reaction time is 10-30 min; the temperature is 15-45℃ (operation is entirely at ambient temperature, eliminating the need for the high temperatures of traditional processes); the number of stages is 2-6. After phase separation, the beryllium back-extractant is obtained and used as a raw material for the subsequent preparation of high-purity beryllium products. The unloaded organic phase then enters the regeneration process.

[0062] (5) Regeneration of the unloaded organic phase (P204 Organic phase recycling)

[0063] The process removes trace amounts of beryllium ions and impurities from the organic phase, restores the extractant's performance, and achieves a closed-loop recycling of the organic phase. Regenerants include: pure water, 0.5-1M sodium hydroxide, potassium hydroxide, ammonia, sodium carbonate, or sodium bicarbonate solution; O / A ratio: 40:1-5:1; single-stage reaction time: 3-10 min; temperature: 15-45℃; number of stages: 2-6; the regenerated organic phase is returned to the beryllium extraction process for reuse, completing the closed-loop beryllium extraction process.

[0064] The technical solution of the present invention will be further described in detail below with reference to several preferred embodiments and accompanying drawings. This embodiment is implemented on the premise of the technical solution of the invention, and provides detailed implementation methods and specific operation processes. However, the protection scope of the present invention is not limited to the following embodiments.

[0065] Unless otherwise specified, the experimental materials used in the examples below can be purchased from conventional biochemical reagent companies.

[0066] The main components of the beryllium-containing aqueous phase in the experiment are shown in Table 1. The beryllium concentration was 3.1 g / L, and the impurities contained high levels of iron and aluminum.

[0067] Table 1. Main physicochemical properties of beryllium-containing aqueous phases

[0068] The present invention will be further described in detail below with reference to embodiments, but the implementation of the present invention is not limited thereto.

[0069] Example 1: 1) Pre-treatment for iron removal: 10 mL of hydrogen peroxide was added to 1 L of beryllium-containing aqueous phase, and ferrous iron was oxidized at 50℃ for 10 min, achieving a 100% oxidation rate. Subsequently, the pH of the aqueous phase was adjusted to 1.0 with sodium hydroxide. Using 20% ​​Versatic 10 + 8% isooctanol + 72% sulfonated kerosene as the extractant, with an O / A ratio of 1:3, a temperature of 35℃, an extraction time of 5 min, and two-stage countercurrent extraction, the iron extraction rate was 100%. Washing was performed with pure water, with an O / A ratio of 5:1, a washing temperature of 35℃, a washing time of 5 min, and two-stage washing, achieving a 5% iron elution rate. Back-extraction was performed using a mixed solution of 6M hydrochloric acid + 3wt% sodium metabisulfite, with an O / A ratio of 5:1, a temperature of 40℃, a back-extraction time of 10 min, and two-stage back-extraction, achieving a 100% iron back-extraction rate. The unloaded organic phase is regenerated using pure water at an O / A ratio of 5:1, a temperature of 30℃, a regeneration time of 5 minutes, and a two-stage regeneration process. The organic phase is then recycled.

[0070] 2) Beryllium Extraction Process: The iron-free beryllium-containing aqueous phase was adjusted to pH 2.9 with sodium hydroxide. 30% P₂O₄ + 15% sec-octanol + 55% sulfonated kerosene was used as the extractant, with an O / A ratio of 1.5:1, a temperature of 30℃, an extraction time of 20 min, and two-stage countercurrent extraction, achieving a beryllium extraction rate of 97%. The beryllium-loaded organic phase was washed with 3% oxalic acid solution, with an O / A ratio of 6:1, a temperature of 30℃, a washing time of 5 min, and three-stage washing, achieving a beryllium elution rate of 6% and an iron and aluminum elution rate of 100%. Back-extraction was performed using 2M sodium hydroxide, with an O / A ratio of 3:1, a temperature of 25℃, a back-extraction time of 15 min, and two-stage back-extraction, achieving a beryllium back-extraction rate of 100%, and the back-extraction solution was clear and free of precipitate. The organic phase was regenerated using 0.5M sodium hydroxide solution, with an O / A ratio of 10:1, a temperature of 30℃, a regeneration time of 5 min, and two-stage regeneration, allowing for the recycling of the organic phase.

[0071] Example 2

[0072] 1) Pre-treatment for iron removal: 1.2 g of sodium chlorate was added to 1 L of beryllium-containing aqueous phase, and ferrous iron was oxidized at 45℃ for 15 min, achieving a 100% oxidation rate. Subsequently, the pH of the aqueous phase was adjusted to 0.8 with sodium carbonate. Using 10% Lix63-5% Primene JM-T + 6% n-octanol + 79% isoalkanes as the extractant, with an O / A ratio of 1:2, a temperature of 40℃, an extraction time of 6 min, and two stages of countercurrent extraction, the iron extraction rate was 100%. Washing was performed with a dilute hydrochloric acid solution at pH 0.8, with an O / A ratio of 6:1, a temperature of 40℃, a washing time of 5 min, and two stages of washing, resulting in a 4% iron elution rate. Back-extraction was performed using a mixed solution of 5M hydrochloric acid and 1 wt% sodium metabisulfite, with an O / A ratio of 6:1, a temperature of 45℃, a back-extraction time of 8 min, and five stages of back-extraction, achieving a 98% iron back-extraction rate. The unloaded organic phase was regenerated using dilute hydrochloric acid with an O / A ratio of 6:1, a temperature of 35°C, a regeneration time of 5 minutes, and a three-stage regeneration process. The organic phase was then recycled.

[0073] 2) Beryllium Extraction Process: The iron-free beryllium-containing aqueous phase was adjusted to pH 2.4 with sodium carbonate. 25% P₂O₄ + 12% isoamyl alcohol + 63% aviation kerosene was used as the extractant, with an O / A ratio of 2:1, a temperature of 35℃, an extraction time of 25 min, and 5 stages of countercurrent extraction, achieving a 100% beryllium extraction rate. The beryllium-loaded organic phase was washed with a 2.5% oxalic acid solution, with an O / A ratio of 5:1, a temperature of 35℃, a washing time of 5 min, and 3 stages of washing, achieving a 4% beryllium elution rate and 100% iron and aluminum elution rates. Back-extraction was performed using 3.5M sulfuric acid, with an O / A ratio of 3:1, a temperature of 25℃, a back-extraction time of 15 min, and 3 stages of back-extraction, achieving a 100% beryllium back-extraction rate, and the back-extraction solution was clear and free of precipitate. The organic phase was regenerated using a 1M sodium carbonate solution, with an O / A ratio of 10:1, a temperature of 35℃, a regeneration time of 5 min, and 3 stages of regeneration, allowing for the recycling of the organic phase.

[0074] Example 3

[0075] 1) Pre-treatment for iron removal: Add 5 mL of hydrogen peroxide to 1 L of beryllium-containing aqueous phase and oxidize ferrous iron at 35℃ for 20 min, achieving a 100% oxidation rate. Then, adjust the pH of the aqueous phase to 1.2 with nitric acid. Use 18% N235 + 7% dodecanol + 75% sulfonated kerosene as the extractant, with an O / A ratio of 1:4, a temperature of 35℃, an extraction time of 5 min, and 3-stage countercurrent extraction, achieving a 99% iron extraction rate. Wash with a dilute nitric acid solution at pH 1.2, with an O / A ratio of 4:1, a temperature of 35℃, a washing time of 5 min, and 3-stage washing, achieving a 5% iron elution rate. Back-extract with a mixed solution of 3M nitric acid and 2 wt% sodium sulfite, with an O / A ratio of 4:1, a temperature of 40℃, a back-extraction time of 10 min, and 3-stage back-extraction, achieving a 100% iron back-extraction rate. The unloaded organic phase was regenerated using dilute sulfuric acid at an O / A ratio of 5:1, a temperature of 30°C, a regeneration time of 5 minutes, and a 4-stage regeneration process. The organic phase was then recycled.

[0076] 2) Beryllium Extraction Process: The iron-free, beryllium-containing aqueous phase was adjusted to pH 2.8 with sulfuric acid. 35% P₂O₄ + 10% sec-octanol + 55% dodecane was used as the extractant, with an O / A ratio of 1.5:1, a temperature of 30℃, an extraction time of 30 min, and 4 stages of countercurrent extraction, achieving a 100% beryllium extraction rate. The beryllium-loaded organic phase was washed with a 3% oxalic acid solution, with an O / A ratio of 6:1, a temperature of 30℃, a washing time of 5 min, and 4 stages of washing, achieving a 7% beryllium elution rate and 100% iron and aluminum elution rates. Back-extraction was performed using 2M potassium hydroxide, with an O / A ratio of 3:1, a temperature of 25℃, a back-extraction time of 15 min, and 3 stages of back-extraction, achieving a 100% beryllium back-extraction rate. The back-extraction solution was clear and free of precipitate. The organic phase was regenerated using pure water, with an O / A ratio of 10:1, a temperature of 30℃, a regeneration time of 5 min, and 4 stages of regeneration, allowing for the recycling of the organic phase.

[0077] This invention employs a pre-extraction process for deep iron removal followed by P204 extraction of beryllium. As demonstrated in Examples 1-3, this invention significantly improves iron and aluminum removal efficiency, beryllium extraction and back-extraction behavior, system stability, and product purity. Specific analysis follows: Examples 1-3 show that iron removal is achieved through oxidation with hydrogen peroxide or sodium chlorate, pre-treatment with extractants such as Versatic 10, Lix series, and N235, resulting in an iron extraction rate of 99%-100%, fundamentally preventing iron from entering the subsequent beryllium extraction system.

[0078] In Examples 1-3, the beryllium extraction rate can reach 97%-100%, while the iron and aluminum elution rate in the washing process can reach 100%.

[0079] Examples 1-3 show that alkaline back-extraction was performed at room temperature of 25°C. The back-extraction solution was clear and transparent, without any precipitate, and the phase separation was rapid and clear.

[0080] After deep removal of iron and aluminum in Examples 1-3, the beryllium purity of the back-extraction liquid is high, and iron and aluminum impurities can be controlled to a qualified level.

[0081] This invention involves no phase change, no precipitation, and no emulsification throughout the entire process, and the organic phase can be stably recycled.

[0082] In summary, this invention solves the problem of iron impurities at the source by removing iron through pre-extraction, significantly improving the beryllium extraction rate and separation accuracy, achieving room temperature clarification and back-extraction, greatly improving product purity and process stability, and the overall effect is significantly better than the traditional direct extraction process.

[0083] The above are merely preferred embodiments of the present invention and do not limit the scope of protection of the present invention. For those skilled in the art, the present invention can have various modifications and variations. Any changes, modifications, substitutions, integrations, and parameter alterations to these embodiments within the spirit and principles of the present invention, achieved through conventional substitutions or by achieving the same function without departing from the principles and spirit of the present invention, fall within the scope of protection of the present invention.

Claims

1. A method for separating and purifying beryllium from a beryllium-containing solution, characterized in that, include: An oxidant is added to a beryllium-containing aqueous phase to oxidize the ferrous ions in the aqueous phase; The pH of the beryllium-containing aqueous phase after oxidation was adjusted to 0.1-2 using acid-base agents; Iron extraction was performed on the conditioned beryllium-containing aqueous phase using an iron extractant, an iron extractant modifier, and an iron extractant diluent to obtain an iron-loaded organic phase and an iron-free beryllium-containing aqueous phase. The beryllium ions in the supported iron organic phase were washed with a detergent. The washed aqueous phase containing beryllium ions is returned to the conditioning process, and the washed iron-loaded organic phase is back-extracted to obtain a high-ferric aqueous phase. The high-iron aqueous phase is sent into the iron recovery system, and the empty organic phase containing trace amounts of iron ions is regenerated and the regenerated organic phase is returned to the iron extraction process. The pH of the iron-free beryllium-containing aqueous phase is adjusted to 1-5, wherein the beryllium concentration is ≤5.0 g / L; The conditioned iron-free beryllium-containing aqueous phase was subjected to beryllium extraction using a beryllium extractant, a beryllium extraction modifier, and a beryllium extraction diluent to obtain a beryllium-loaded organic phase and a raffinate aqueous phase. Wash away impurity ions from the supported beryllium organic phase; A back-extraction agent was used to back-extract the loaded beryllium organic phase after removing impurity ions, resulting in a beryllium back-extractant and an empty organic phase containing trace amounts of beryllium ions. An organic phase containing trace amounts of beryllium ions is regenerated using a regenerating agent, and the regenerated organic phase is then returned to the beryllium extraction process.

2. The method for separating and purifying beryllium from a beryllium-containing solution according to claim 1, characterized in that, In the process of adding an oxidant to a beryllium-containing aqueous phase to oxidize ferrous ions in the aqueous phase, the oxidation conditions are: temperature 15~80℃, oxidation time 1min~72h, and the amount of oxidant added is 2 times or more of the ferrous ions. The oxidant is selected from any one of sodium chlorate, hydrogen peroxide, potassium permanganate, or ozone.

3. The method for separating and purifying beryllium from a beryllium-containing solution according to claim 1, characterized in that, The acid or base agent is selected from any one of sodium hydroxide, sodium carbonate, sulfuric acid, hydrochloric acid, or nitric acid.

4. The method for separating and purifying beryllium from a beryllium-containing solution according to claim 1, characterized in that, In the process of extracting iron from a conditioned beryllium-containing aqueous phase using an iron extractant, an iron extractant modifier, and an iron extractant diluent, an iron-loaded organic phase and an iron-free beryllium-containing aqueous phase are obtained. The ratio of the iron extractant, the iron extract modifier, and the iron extract diluent is 5-40%, 5-20%, and 90-40%, respectively. The iron extractant is selected from any one of Lix54, Lix63, Lix64N, Lix984, N910, N1923, Primene JM-T, N235, N503, TIOA, CA12, Versatic 10, naphthenic acid 70, naphthenic acid 75, and naphthenic acid 80. The iron extraction modifier is selected from any one of isooctanol, isoamyl alcohol, isodecyl alcohol, isobutanol, n-octanol, n-decyl alcohol, n-butanol, sec-octanol, dodecanol, and β-branched primary alcohols; The iron extraction diluent is selected from any one of sulfonated kerosene, isoalkanes, aviation kerosene, and dodecane; The iron extraction conditions are: O / A = 1:1~1:10, extraction time 3min-30min, temperature 25~60℃, and number of stages 2~6.

5. The method for separating and purifying beryllium from a beryllium-containing solution according to claim 1, characterized in that, In the process of washing the beryllium ions in the supported iron organic phase with a detergent, the detergent is selected from any one of sulfuric acid solution, hydrochloric acid solution, and nitric acid solution with a pH value of 0.2 to 2.0; The washing conditions are: O / A = 10:1~2:1, single-stage reaction time 3~10 min, temperature 25~60℃, and washing stages 2~6.

6. The method for separating and purifying beryllium from a beryllium-containing solution according to claim 1, characterized in that, In the process of back-extracting the washed iron-loaded organic phase to obtain the high-ferrous aqueous phase, the back-extraction agent used in the back-extraction process is a mixed solution of 0.1~3M hydrochloric acid or nitric acid and 0.1wt%~5wt% sodium metabisulfite or sodium sulfite. The back-extraction conditions are: O / A = 10:1~2:1, single-stage reaction time 3~20 min, temperature 25~60℃, and 2~6 back-extraction stages.

7. The method for separating and purifying beryllium from a beryllium-containing solution according to claim 1, characterized in that, In the process of regenerating an empty organic phase containing trace amounts of iron ions, the regenerator used in the regeneration process is selected from any one of pure water, dilute sulfuric acid, dilute hydrochloric acid, or dilute nitric acid. The regeneration conditions are: O / A = 1:1~10:1, single-stage reaction time 3~10 min, temperature 25~55℃, and number of regeneration stages 2~6.

8. The method for separating and purifying beryllium from a beryllium-containing solution according to claim 1, characterized in that, The pH of the iron-free beryllium-containing aqueous phase is adjusted to 1-5 using sodium hydroxide, sodium carbonate, or sulfuric acid.

9. The method for separating and purifying beryllium from a beryllium-containing solution according to claim 1, characterized in that, In the process of beryllium extraction of the conditioned iron-free beryllium-containing aqueous phase using beryllium extractant, beryllium extract modifier and beryllium extract diluent, wherein the beryllium extractant is P204; The beryllium extraction modifier is selected from any one of isooctanol, isoamyl alcohol, isodecyl alcohol, isobutanol, n-octanol, n-decyl alcohol, n-butanol, sec-octanol, dodecanol, and β-branched primary alcohols; The beryllium extraction diluent is selected from any one of sulfonated kerosene, isoalkanes, aviation kerosene, and dodecane; The ratio of the beryllium extractant, the beryllium extract modifier, and the beryllium extract diluent is: 10%~40%, 0~20%, and 40%~90%, respectively. The beryllium extraction conditions are: O / A = 5:1~1:3, single-stage reaction time 5~60 min, temperature 15~45℃, and 2~6 stages of countercurrent extraction.

10. The method for separating and purifying beryllium from a beryllium-containing solution according to claim 1, characterized in that, During the washing process of impurity ions in the supported beryllium organic phase The detergent used in the washing process is any one of the following: 1%~5% oxalic acid solution, 0.01-2M hydroxyethylidene diphosphine solution, triethylenetetramine hexaacetic acid solution, or aqueous acetic acid solution; The washing conditions are: O / A = 15:1~2:1, single-stage reaction time 3~10 min, temperature 15~45℃, and washing stages 2~6.

11. The method for separating and purifying beryllium from a beryllium-containing solution according to claim 1, characterized in that, In the process of back-extracting the supported beryllium organic phase to remove impurity ions using a back-extracting agent, the back-extracting agent is selected from any one of 1-5M sodium hydroxide, 1-6M sulfuric acid, or hydrochloric acid; The beryllium back-extraction conditions are: O / A = 15:1~2:1; single-stage reaction time 10~30 min; temperature 15~45℃; 2~6 stages of countercurrent extraction.

12. The method for separating and purifying beryllium from a beryllium-containing solution according to claim 1, characterized in that, In the process of regenerating an empty organic phase containing trace amounts of beryllium ions using a regenerant, the regenerant is selected from any one of pure water, sodium hydroxide, potassium hydroxide, ammonia, sodium carbonate, and sodium bicarbonate solution. The regeneration conditions are: O / A = 40:1~5:1, single-stage reaction time 3~10 min, temperature 15~45℃; number of regeneration stages 2~6.

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