Method for extracting rhenium from rhenium-containing solution difficult to treat

Abstract

The invention discloses a method for extracting rhenium from a rhenium-containing solution difficult to treat. The method comprises the steps of transformation pretreatment, precise filtration, extraction, reverse extraction, concentration and crystallization. The method for extracting the rhenium from the rhenium-containing solution difficult to treat comprises the steps of transformation pretreatment and precise filtration, the transformation pretreatment utilizes the principle that the solubility of arsenic trioxide is increased along with temperature rise, the rhenium-containing solution difficult to treat is subjected to heating treatment, so that organic impurities in a liquid phase are removed, and the rhenium is extracted from the rhenium-containing solution difficult to treat. Meanwhile, suspended fine-particle arsenic trioxide impurities difficult to filter are dissolved and enter a liquid phase, the heated liquid is cooled and left to stand, supersaturated arsenic trioxide impurities in the liquid phase are separated out again, the purpose of changing the crystal form of arsenic trioxide is achieved, then arsenic trioxide with the changed crystal form is removed through precise filtration, and purified liquid is obtained; due to the fact that suspended fine-particle arsenic trioxide impurities difficult to filter and organic impurities are removed in the process at the same time, an emulsified third phase cannot occur in the extraction process, and rhenium can be well recycled.

Description

Technical Field

[0001] The present invention relates to the technical field of nonferrous metal metallurgy, and more particularly to a method for producing a high-purity ammonium rhenate product from a difficult-to-treat rhenium-containing solution as a raw material. Background Art

[0002] Rhenium (chemical symbol: Re) is a rare, high-melting-point metallic element widely used in electronics, military, aerospace, and other fields. For example, rhenium and its alloys exhibit excellent high-temperature strength, corrosion resistance, and creep resistance, making them key materials for the manufacture of single-crystal turbine blades for aircraft engines. These blades operate in harsh environments characterized by high temperatures, high pressures, and high rotational speeds. The use of rhenium alloys can significantly improve blade performance and reliability, extending engine life and increasing thrust and efficiency. Rhenium alloys also play a crucial role in components such as rocket engine nozzles and combustion chambers, withstanding high temperatures and high-velocity airflow to ensure proper operation. Furthermore, rhenium can be used to manufacture high-performance semiconductor devices such as field-effect transistors and diodes. Its unique electronic properties enhance device performance and stability, meeting the high-speed, high-frequency, and low-power requirements of modern electronics.

[0003] Global rhenium production primarily relies on the enrichment and recovery of copper and molybdenum from porphyry copper deposits. Currently, the most commonly used industrial rhenium recovery methods include chemical precipitation, ion exchange, and extraction-crystallization.

[0004] Prior art CN102433439A (filing date December 16, 2011) provides a method for recovering rhenium from arsenic filter cakes, comprising: first grinding the arsenic filter cake, then adding alkaline solution for primary leaching, filtering to obtain a primary leachate and a primary leach residue; then adding an oxidant to the primary leach residue for secondary leaching, filtering to obtain a secondary leachate and a secondary leach residue; then adding an oxidant to the primary leachate for oxidation; then combining the oxidized primary leachate with the secondary leachate, and removing arsenic by sulfur dioxide reduction or lime precipitation; then separating and enriching rhenium by extraction, and evaporating, concentrating, and crystallizing the raffinate to produce Glauber's salt; then concentrating the rhenium-enriched extract, adding potassium chloride, cooling, and crystallizing to precipitate crude potassium perrhenate, which is then recrystallized to produce refined potassium perrhenate. This prior art uses arsenic filter cake as a raw material, requiring arsenic removal, followed by extraction and crystallization to produce ammonium rhenate.

[0005] When using the extraction-crystallization method to produce ammonium rhenate, the system's rhenium recovery rate rarely exceeds 95%. The main reason for rhenium loss during the production process is that the difficult-to-handle rhenium-containing solution quickly absorbs and encapsulates organic impurities upon entering the extraction system, forming an emulsified third phase. This difficulty in separating the rhenium from the solution hinders normal production, forcing open-circuit treatment, which reduces rhenium recovery and creates challenges for traditional rhenium extraction and recovery processes.

[0006] How to solve the emulsification problem in the extraction process of difficult-to-treat rhenium-containing solutions, realize rhenium recovery, and obtain high-quality ammonium rhenate products is an urgent problem to be solved. Summary of the Invention

[0007] In view of this, the present invention provides a method for extracting rhenium from a difficult-to-treat rhenium-containing solution.

[0008] The present invention provides a method for extracting rhenium from a difficult-to-treat rhenium-containing solution, comprising:

[0009] Transformation pretreatment, performing temperature transformation on a difficult-to-treat rhenium-containing solution, wherein the difficult-to-treat rhenium-containing solution is a rhenium-containing solution containing difficult-to-filter suspended fine particles of As2O3 impurities, as well as Cu, As, Re, Sb, Bi, and organic impurities, wherein the temperature transformation volatilizes the organic impurities and dissolves the difficult-to-filter suspended fine particles of As2O3 impurities into a liquid phase to obtain a rhenium-containing solution, and the rhenium-containing solution is cooled and allowed to stand to obtain a cooled liquid; wherein the temperature during the temperature transformation process is 60°C-100°C and the time is 2h-12h; the temperature during the cooling process is -5°C-40°C and the standing time is 2h-12h;

[0010] Precision filtration, filtering the cooled liquid to obtain a purified liquid, wherein the filter pore size is 0.1 μm-5 μm;

[0011] Extraction, adding the purified liquid to an extraction reagent to obtain a loaded organic phase;

[0012] Stripping, using aqueous ammonia to strip the loaded organic phase to obtain a rhenium-containing stripping solution;

[0013] Concentrating, concentrating the rhenium-containing stripping solution to obtain a concentrated solution;

[0014] Crystallization, the concentrated liquid is cooled and crystallized.

[0015] The difficult-to-treat rhenium-containing solution mainly contains difficult-to-filter As2O3, which is difficult to filter out directly. In addition, some Cu, As, Sb, and Bi can also be removed.

[0016] Optionally, the extractant includes trioctyldecyl tertiary amine, trioctylamine or kerosene.

[0017] Optionally, the volume ratio of the purified liquid to the extraction reagent is (10-100):1.

[0018] Optionally, the volume ratio of the ammonia water to the loaded organic phase is (1-3):1.

[0019] Optionally, the concentration specific gravity during the concentration process is 1.03 g / cm 3 -1.18g / cm 3.

[0020] Optionally, the cooling temperature during the crystallization process is -15°C to 5°C.

[0021] Compared with the prior art, the method for extracting rhenium from a difficult-to-treat rhenium-containing solution provided by the present invention achieves at least the following beneficial effects:

[0022] In the prior art, since the difficult-to-treat rhenium-containing solution contains difficult-to-filter suspended fine particles of As2O3 impurities and organic impurities, if the difficult-to-filter suspended fine particles of As2O3 impurities are directly filtered and then extracted, due to their fine particles, they are difficult to filter out and will enter the extraction system together. Since their specific gravity is between that of the rhenium-containing solution (liquid phase) and the extractant (oil phase), it is difficult to separate them after extraction, so the rhenium recovery rate is low; as for organic impurities, after entering the extraction system, the difficult-to-treat rhenium-containing solution will quickly adsorb and encapsulate the organic impurities to form an emulsified third phase, which is difficult to separate. The above two substances make rhenium recovery difficult. The method of extracting rhenium from a difficult-to-treat rhenium-containing solution of the present invention utilizes the principle that the solubility of arsenic trioxide increases with increasing temperature. By heating the difficult-to-treat rhenium-containing solution, organic impurities in the liquid phase are removed, and at the same time, suspended fine particles of arsenic trioxide impurities that are difficult to filter are dissolved into the liquid phase. After the temperature is increased, the liquid is cooled and allowed to stand, and supersaturated arsenic trioxide impurities in the liquid phase are precipitated again, thereby achieving the purpose of changing the crystal form of arsenic trioxide. The arsenic trioxide with changed crystal form is then removed by precise filtration. In the obtained purified liquid, since the difficult-to-filter suspended fine particles of arsenic trioxide impurities and organic impurities are removed in the process, no emulsified third phase will appear during the extraction process, and better recovery of rhenium can be achieved.

[0023] The method of extracting rhenium from a difficult-to-treat rhenium-containing solution of the present invention realizes the extraction and recovery of rhenium from the difficult-to-treat rhenium-containing solution for the first time, and converts the rhenium into a high-purity ammonium rhenate product.

[0024] The method is simple to operate and low in cost, can effectively extract and recover rhenium from difficult-to-treat rhenium-containing solutions, and has a significant effect on improving the rhenium recovery rate in the process of producing ammonium rhenate by an extraction process.

[0025] Of course, any product implementing the present invention does not necessarily need to achieve all of the technical effects described above at the same time.

[0026] Further features and advantages of the present invention will become apparent from the following detailed description of exemplary embodiments of the present invention with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.

[0028] Figure 1 The present invention provides a flow chart of a method for extracting rhenium from a difficult-to-treat rhenium-containing solution. DETAILED DESCRIPTION

[0029] Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that unless otherwise specifically stated, the relative arrangement of components and steps, numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present invention.

[0030] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the invention, its application, or uses.

[0031] Technologies, methods, and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods, and equipment should be considered part of the specification.

[0032] In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not limiting. Therefore, other examples of the exemplary embodiments may have different values.

[0033] It should be noted that like reference numerals and letters refer to like items in the following figures, and therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0034] Combine Figure 1 The present invention provides a method for extracting rhenium from a difficult-to-treat rhenium-containing solution, comprising:

[0035] S101, transformation pretreatment, performing temperature transformation on a difficult-to-treat rhenium-containing solution, wherein the difficult-to-treat rhenium-containing solution is a rhenium-containing solution containing difficult-to-filter suspended fine particles of As2O3 impurities, as well as Cu, As, Re, Sb, Bi, and organic impurities. The temperature transformation volatilizes the organic impurities and dissolves the difficult-to-filter suspended fine particles of As2O3 impurities into the liquid phase to obtain a rhenium-containing solution, and the rhenium-containing solution is cooled and allowed to stand to obtain a cooled liquid; wherein the temperature during the temperature transformation process is 60°C-100°C and the time is 2h-12h; the temperature during the cooling process is -5°C-40°C and the standing time is 2h-12h;

[0036] Specifically, utilizing the principle that the solubility of arsenic trioxide increases with increasing temperature, the difficult-to-treat rhenium-containing solution is heated to remove organic impurities in the liquid phase, while difficult-to-filter suspended fine particles of arsenic trioxide impurities dissolve into the liquid phase. After heating, the liquid is cooled and allowed to stand, and the supersaturated arsenic trioxide impurities in the liquid phase are precipitated again, thereby achieving the purpose of changing the crystal form of arsenic trioxide.

[0037] It should be noted that after the crystal form of arsenic trioxide changes, a small part of it dissolves in the solution, passes through the extraction process, and enters the wastewater treatment with the extracted solution; most of it forms larger particles, and the part that forms larger particles is removed by precision filtration.

[0038] Optionally, the temperature during the temperature-raising transition process can be any value among 60°C, 70°C, 80°C, 90°C, 100°C, or any range between any two of the above points. A temperature that is too low is not conducive to the volatilization of organic impurities, nor is it conducive to the difficult-to-filter suspended fine particles As2O3 impurities entering the liquid phase. A temperature that is too high will increase energy consumption on the one hand, and on the other hand, after the organic impurities are volatilized and the difficult-to-filter suspended fine particles As2O3 impurities have all entered the liquid phase, continuing to heat up will result in cost waste. The time during the temperature-raising transition process can be any value among 2h, 3h, 4h, 5h, 6h, 7h, 8h, 9h, 10h, 11h, 12h, or any range between any two of the above points. A temperature-raising time that is too short is not conducive to the volatilization of organic impurities, nor is it conducive to the difficult-to-filter suspended fine particles As2O3 impurities entering the liquid phase. A temperature-raising time that is too long will increase energy consumption on the one hand, and on the other hand, after the organic impurities are volatilized and the difficult-to-filter suspended fine particles As2O3 impurities have all entered the liquid phase, continuing to extend the time will result in cost waste.

[0039] Optionally, the cooling temperature can be -5°C, 0°C, 5°C, 10°C, 15°C, 20°C, 25°C, 30°C, 35°C, 40°C, or any range between any two of the above, and the standing time can be any of 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, 9 hours, 10 hours, 11 hours, or 12 hours, or any range between any two of the above. The cooling process is the process of precipitating arsenic trioxide crystals. The arsenic trioxide crystals in this process are difficult to process. The difficult-to-filter suspended fine particles of As2O3 impurities in the rhenium-containing solution are large and are more easily removed by subsequent filtration.

[0040] S102, precision filtration, filtering the cooled liquid to obtain a purified liquid, wherein the filter pore size is 0.1 μm-5 μm;

[0041] Optionally, the filter pore size can be 0.1 μm, 0.5 μm, 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, or any range between any two of the above points. A filter pore size that is too small will increase the filtration resistance and be prone to clogging. A filter pore size that is too large will not be able to retain arsenic trioxide crystals. The dissolved and reprecipitated arsenic trioxide crystals are relatively large. Setting the filter pore size to 0.1 μm-5 μm can filter out the arsenic trioxide crystals without increasing the filtration resistance and causing the filter pores to clog. Of course, this precision filtration process will also filter out other particles in the rhenium-containing solution.

[0042] S103, extraction, adding the purified liquid to an extraction reagent to obtain a loaded organic phase;

[0043] Specifically, after extraction, the rhenium in the difficult-to-treat rhenium-containing solution is extracted into the extraction reagent, while arsenic trioxide remains in the solution and is separated from the rhenium. The extraction principle: The extraction reagent has a high selectivity for rhenium. The rhenium in the solution is selectively extracted by the extraction reagent, while being completely separated from the solution containing a large amount of impurities, achieving the purpose of separating impurities and enriching rhenium.

[0044] After extraction, the rhenium in the difficult-to-treat rhenium solution is extracted into the extraction reagent, while arsenic trioxide remains in the solution and is separated from the rhenium. Extraction Principle: The extraction reagent has a high selectivity for rhenium. The rhenium in the solution is selectively extracted by the extraction reagent, while being completely separated from the solution containing a large amount of impurities, achieving the purpose of separating impurities and enriching rhenium.

[0045] S104, stripping, stripping the loaded organic phase with aqueous ammonia to obtain a rhenium-containing stripping solution;

[0046] Specifically, rhenium (Re) in the loaded organic phase is transferred from the organic extractant to the aqueous phase by ammonia water (NH 3 ·H 2 O) to form a rhenium-containing stripping solution (ammonium rhenate or rhenate ion solution).

[0047] Rhenium usually exists in the organic phase in the form of a complex (such as ReO2·L, where L is the extractant).

[0048] Ammonia provides OH- and NH3 molecules, which compete with the rhenium complex for coordination or ion exchange reaction:

[0049] ReO2·L(org)+nNH3+H2O→ReO4-(aq)+NH4+(aq)+L(org)+by-product

[0050] Finally, water-soluble rhenate (ReO4 - ) or ammonium rhenate ((NH4)ReO4).

[0051] S105, concentrating, concentrating the rhenium-containing stripping solution to obtain a concentrated solution;

[0052] Specifically, the rhenium stripping solution (containing ReO4 - NH4 + The water in the mixture is evaporated to increase the rhenium concentration to the target specific gravity. The concentration method can be evaporation concentration commonly used in the prior art, of course, membrane concentration in the prior art can also be used, and is not specifically limited here.

[0053] S106, crystallization, cooling the concentrated liquid for crystallization.

[0054] Specifically, by cooling the concentrated liquid, target products such as ammonium rhenate (or rhenic acid) are precipitated in the form of crystals, achieving solid-liquid separation and improving product purity and recovery rate.

[0055] The difficult-to-treat rhenium-containing solution mainly contains difficult-to-filter As2O3, which is difficult to filter out directly. In addition, some Cu, As, Sb, and Bi can also be removed.

[0056] Optionally, the extractant comprises trioctyldecyl tertiary amine, trioctylamine or kerosene.

[0057] Optionally, the volume ratio of the purified liquid to the extraction reagent is (10-100):1.

[0058] Optionally, the volume ratio of ammonia water to the loaded organic phase is (1-3):1.

[0059] Specifically, a high phase ratio (e.g., 1:1) is suitable for rapid stripping, but requires an increase in the amount of aqueous ammonia. A low phase ratio (e.g., 1:3) can reduce the amount of aqueous ammonia, but requires a longer contact time.

[0060] Optionally, the concentration density during the concentration process is 1.03 g / cm 3 -1.18g / cm 3 .

[0061] Optionally, the concentrated specific gravity can be 1.03 g / cm 3 , 1.05g / cm 3 , 1.07g / cm 3 、1.09g / cm 3 , 1.12g / cm 3 , 1.14g / cm 3 , 1.16g / cm 3 , 1.18g / cm 3 Or any range of values ​​between any two of the above points, corresponding to about 5%-20% solid content.

[0062] Optionally, the cooling temperature is -15°C to 5°C.

[0063] Specifically, the cooling temperature range of -15°C to 5°C can promote slow crystal growth and reduce impurity inclusion.

[0064] Example 1

[0065] The difficult-to-treat rhenium-containing solution mainly contains Cu, As, Re, Sb, Bi elements and suspended fine particles of As2O3 impurities. During the heating process, the reaction temperature is controlled at 60°C and the reaction time is controlled at 2 hours, so that the impurities such as the difficult-to-filter fine particles of As2O3 in the liquid phase are dissolved into the liquid phase and the organic impurities are removed. The obtained rhenium-containing solution is cooled to -5°C and allowed to stand for 2 hours to obtain a cooled liquid. Then, it is finely filtered (filtration pore size 0.1um) to obtain a purified liquid. The purified liquid is added to the extraction reagent for extraction, and the volume ratio of the purified liquid to the extraction reagent is controlled to be 10:1 to obtain a loaded organic phase. The loaded organic phase is stripped with 8% ammonia water, and the volume ratio of ammonia water to the loaded organic phase is controlled to be 1:1 to obtain a rhenium-containing stripping solution. The rhenium stripping solution is concentrated to control the specific gravity to be 1.03g / cm 3 , and obtain a concentrated liquid, which is cooled and crystallized, with the cooling temperature controlled at -15°C to obtain a high-purity ammonium rhenate product.

[0066] The difficult-to-treat rhenium solution contains 202 mg / l of rhenium. After the above steps, the treated solution contains 3 mg / l of rhenium. The rhenium recovery rate is: (202-3)÷202×100%=98.51%, and the rhenium recovery rate is ≥95%.

[0067] Example 2

[0068] The difficult-to-treat rhenium-containing solution mainly contains Cu, As, Re, Sb, Bi elements and suspended fine particles of As2O3 impurities. During the heating process, the reaction temperature is controlled at 100°C and the reaction time is 12 hours, so that the impurities such as the difficult-to-filter fine particles of As2O3 in the liquid phase are dissolved into the liquid phase and the organic impurities are removed. The obtained rhenium-containing solution is cooled to 40°C and allowed to stand for 12 hours to obtain a cooled liquid. Then, it is finely filtered (filtration pore size 5um) to obtain a purified liquid. The purified liquid is added to the extraction reagent for extraction, and the volume ratio of the purified liquid to the extraction reagent is controlled to be 100:1 to obtain a loaded organic phase. The loaded organic phase is stripped with 16% ammonia water, and the volume ratio of ammonia water to the loaded organic phase is controlled to be 3:1 to obtain a rhenium-containing stripping solution. The rhenium stripping solution is concentrated to control the specific gravity to be 1.18g / cm 3 , and obtain a concentrated liquid, which is cooled and crystallized, with the cooling temperature controlled at 5°C to obtain a high-purity ammonium rhenate product.

[0069] The difficult-to-treat rhenium-containing solution contains 208 mg / l of rhenium. After the above steps, the treated solution contains 6 mg / l of rhenium. The rhenium recovery rate is: (208-6)÷208×100%=97.11%, and the rhenium recovery rate is ≥95%.

[0070] Example 3

[0071] The difficult-to-treat rhenium-containing solution mainly contains Cu, As, Re, Sb, Bi elements and suspended fine particles of As2O3 impurities. During the heating process, the reaction temperature is controlled at 80°C and the reaction time is controlled at 8 hours, so that the impurities such as the difficult-to-filter fine particles of As2O3 in the liquid phase are dissolved into the liquid phase and the organic impurities are removed. The obtained rhenium-containing solution is cooled by 25°C and allowed to stand for 6 hours to obtain a cooled liquid. Then, it is finely filtered (filtration pore size 2um) to obtain a purified liquid. The purified liquid is added to the extraction reagent for extraction, and the volume ratio of the purified liquid to the extraction reagent is controlled to be 80:1 to obtain a loaded organic phase. The loaded organic phase is stripped with 10% ammonia water, and the volume ratio of ammonia water to the loaded organic phase is controlled to be 2:1 to obtain a rhenium-containing stripping solution. The rhenium stripping solution is concentrated to control the specific gravity to be 1.12g / cm 3 , and obtain a concentrated liquid, which is cooled and crystallized at a temperature of -8°C to obtain a high-purity ammonium rhenate product.

[0072] The difficult-to-treat rhenium-containing solution contains 194 mg / l of rhenium. After the above steps, the treated solution contains 5 mg / l of rhenium. The rhenium recovery rate is: (194-5)÷194×100%=97.42%, and the rhenium recovery rate is ≥95%.

[0073] Example 4

[0074] The difficult-to-treat rhenium-containing solution mainly contains Cu, As, Re, Sb, Bi elements and suspended fine particles of As2O3 impurities. During the heating process, the reaction temperature is controlled at 75°C and the reaction time is controlled at 6 hours to dissolve the impurities such as the difficult-to-filter fine particles of As2O3 in the liquid phase into the liquid phase and remove the organic impurities. The obtained rhenium-containing solution is cooled by 15°C and allowed to stand for 4 hours to obtain a cooled liquid. Then, it is finely filtered (filtration pore size 1um) to obtain a purified liquid. The purified liquid is added to the extraction reagent for extraction, and the volume ratio of the purified liquid to the extraction reagent is controlled to be 30:1 to obtain a loaded organic phase. The loaded organic phase is stripped with 12% ammonia water, and the volume ratio of ammonia water to the loaded organic phase is controlled to be 1.5:1 to obtain a rhenium-containing stripping solution. The rhenium stripping solution is concentrated to control the specific gravity to be 1.06g / cm 3 , and obtain a concentrated liquid, which is cooled and crystallized, with the cooling temperature controlled at -11°C to obtain a high-purity ammonium rhenate product.

[0075] The difficult-to-treat rhenium solution contains 201 mg / l of rhenium. After the above steps, the treated solution contains 5 mg / l of rhenium. The rhenium recovery rate is: (201-5)÷201×100%=97.51%, and the rhenium recovery rate is ≥95%.

[0076] Through the above embodiments, the method for extracting rhenium from a difficult-to-treat rhenium-containing solution provided by the present invention achieves at least the following beneficial effects:

[0077] The method of extracting rhenium from a difficult-to-treat rhenium-containing solution of the present invention utilizes the principle that the solubility of arsenic trioxide increases with increasing temperature. By heating the difficult-to-treat rhenium-containing solution, organic impurities in the liquid phase are removed, and at the same time, suspended fine particles of arsenic trioxide impurities that are difficult to filter are dissolved into the liquid phase. After the temperature is increased, the liquid is cooled and allowed to stand, and supersaturated arsenic trioxide impurities in the liquid phase are precipitated again, thereby achieving the purpose of changing the crystal form of arsenic trioxide. The arsenic trioxide with changed crystal form is then removed by precise filtration. In the obtained purified liquid, since the difficult-to-filter suspended fine particles of arsenic trioxide impurities and organic impurities are removed in the process, no emulsified third phase will appear during the extraction process, and better recovery of rhenium can be achieved.

[0078] The method of extracting rhenium from a difficult-to-treat rhenium-containing solution of the present invention realizes the extraction and recovery of rhenium from the difficult-to-treat rhenium-containing solution for the first time, and converts the rhenium into a high-purity ammonium rhenate product.

[0079] The method is simple to operate and low in cost, can effectively extract and recover rhenium from difficult-to-treat rhenium-containing solutions, and has a significant effect on improving the rhenium recovery rate in the process of producing ammonium rhenate by an extraction process.

[0080] Although some specific embodiments of the present invention have been described in detail by way of examples, it should be understood by those skilled in the art that the above examples are for illustration only and are not intended to limit the scope of the present invention. It should be understood by those skilled in the art that modifications may be made to the above embodiments without departing from the scope and spirit of the present invention. The scope of the present invention is defined by the appended claims.

Claims

1. A method for extracting rhenium from a difficult-to-treat rhenium-containing solution, characterized in that: include: Transformation pretreatment, performing temperature transformation on a difficult-to-treat rhenium-containing solution, wherein the difficult-to-treat rhenium-containing solution is a rhenium-containing solution containing difficult-to-filter suspended fine particles of As2O3 impurities, as well as Cu, As, Re, Sb, Bi, and organic impurities, wherein the temperature transformation volatilizes the organic impurities and dissolves the difficult-to-filter suspended fine particles of As2O3 impurities into the liquid phase to obtain a rhenium-containing solution, and then the rhenium-containing solution is cooled and allowed to stand, and supersaturated As2O3 impurities in the liquid phase are precipitated to obtain a cooled liquid; wherein the temperature during the temperature transformation process is 60°C-100°C and the time is 2h-12h; the temperature during the cooling process is -5°C-40°C and the standing time is 2h-12h; Precision filtration, filtering the cooled liquid to obtain a purified liquid, wherein the filter pore size is 0.1 μm-5 μm; Extraction, adding the purified liquid to an extraction reagent to obtain a loaded organic phase; Stripping, using aqueous ammonia to strip the loaded organic phase to obtain a rhenium-containing stripping solution; Concentrating, concentrating the rhenium-containing stripping solution to obtain a concentrated solution; Crystallization, the concentrated liquid is cooled and crystallized.

2. The method for extracting rhenium from a difficult-to-treat rhenium-containing solution according to claim 1, wherein: The extractant includes trioctyldecyl tertiary amine, trioctylamine or kerosene.

3. The method for extracting rhenium from a difficult-to-treat rhenium-containing solution according to claim 1, wherein: The volume ratio of the purified liquid to the extraction reagent is (10-100):

1.

4. The method for extracting rhenium from a difficult-to-treat rhenium-containing solution according to claim 1, wherein: The volume ratio of the ammonia water to the loaded organic phase is (1-3):

1.

5. The method for extracting rhenium from a difficult-to-treat rhenium-containing solution according to claim 1, wherein: The concentration specific gravity during the concentration process is 1.03 g / cm 3 -1.18g / cm 3 .

6. The method for extracting rhenium from a difficult-to-treat rhenium-containing solution according to claim 1, wherein: The cooling temperature during the crystallization process is -15°C to 5°C.

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