Method for recovering rhenium in copper smelting waste acid

Abstract

The invention provides a method for recovering rhenium in copper smelting waste acid, and relates to the technical field of resource recovery, the method comprises the following steps: S1, synthesizing an organic sulfur compound, and slowly releasing active sulfur by the synthesized organic sulfur compound in an acid environment; s2, the synthesized organic sulfur compound serves as a precipitator to be added into the copper smelting waste acid, the organic sulfur compound slowly releases active sulfur, the active sulfur reacts with rhenium to form sulfur-rhenium compound sediment, and rhenium enrichment is achieved; s3, the precipitated solution is subjected to solid-liquid separation, and rhenium-rich slag and a separated solution are obtained; and S4, the rhenium-rich slag is washed and dried, and rhenium metal is further extracted. According to the method, the precipitation method is selected to be combined with the specific organic sulfur compound, the precipitation condition is regulated and controlled through the controlled potential, the rhenium in the waste acid is efficiently enriched and recycled, the rhenium-rich slag containing 2-3% of rhenium is obtained, and the problems existing in an existing rhenium recycling method are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of metal recovery, and in particular to a method for recovering rhenium from waste acid in copper smelting, and more particularly to a process for enriching rhenium by utilizing a selective precipitation method in combination with specific organic sulfur compounds, and achieving efficient recovery through potential control. Background Art

[0002] Rhenium is a rare metal with important applications in aerospace, petrochemicals and other fields. The waste acid produced during copper smelting usually contains a certain amount of rhenium, with an average content of 8-15 mg / L. However, due to the complex composition, high acidity and low rhenium content of the waste acid, the recovery of rhenium faces many challenges.

[0003] Currently, the main methods for recovering rhenium from contaminated acid include solvent extraction and ion exchange. Although solvent extraction has high selectivity and recovery rate, it has problems such as expensive extractants and easy secondary pollution. Ion exchange has high requirements for equipment, and the resin is easily deactivated in an acidic environment, resulting in low recovery efficiency. Therefore, the development of an efficient, environmentally friendly and low-cost rhenium recovery method is of great practical significance.

[0004] The selective precipitation method has certain application potential in the field of metal recovery due to its advantages such as simple operation and low cost. However, traditional precipitants have difficulty in achieving efficient and selective precipitation of rhenium in the acidic environment of waste acid. The present invention aims to develop a new type of organosulfur compound as a precipitant, utilizing its special properties in acidic environments to achieve efficient enrichment and recovery of rhenium in copper smelting waste acid. Summary of the Invention

[0005] In response to the above problems, the present invention provides a method for recovering rhenium from copper smelting waste acid. The purpose of the present invention is to provide a method for recovering rhenium from copper smelting waste acid. By selecting a precipitation method combined with a specific organic sulfur compound and using potential control to regulate the precipitation conditions, efficient enrichment and recovery of rhenium in the waste acid is achieved, and a rhenium-rich slag containing 2-3% rhenium is obtained, thereby solving the problems existing in existing rhenium recovery methods.

[0006] In order to solve the above problems, the technical solution adopted by the present invention is:

[0007] A method for recovering rhenium from copper smelting waste acid comprises the following steps: S1, synthesizing an organic sulfur compound, wherein the synthesized organic sulfur compound slowly releases active sulfur in an acidic environment; S2, adding the synthesized organic sulfur compound as a precipitant to the copper smelting waste acid, causing the organic sulfur compound to slowly release active sulfur, which reacts with rhenium to form a sulfur-rhenium compound precipitate, thereby enriching rhenium; S3, performing solid-liquid separation on the precipitated solution to obtain rhenium-rich slag and the separated solution; and S4, washing and drying the rhenium-rich slag to further extract rhenium metal.

[0008] Preferably, in step S1, an unsaturated hydrocarbon compound containing a double bond, a compound containing a thiol group, and an initiator are used as synthetic raw materials to form an organic sulfur compound containing a thioether bond.

[0009] Preferably, the unsaturated hydrocarbon compound and the thiol-containing compound are added to a reaction vessel in a molar ratio of 1:1-1.5, an appropriate amount of initiator is added, and the reaction is stirred at 60-80° C. under nitrogen protection for 3-5 hours to obtain an organic sulfur compound.

[0010] Preferably, the initiator accounts for 0.5-2% of the total mass of the reactants.

[0011] Preferably, the amount of the precipitant added in step S2 is 1.2-1.5 times the theoretical amount of rhenium precipitated in the waste acid.

[0012] Preferably, while adding the precipitant, an appropriate amount of oxygen or air is introduced into the waste acid, and the potential of the solution is monitored in real time using a potentiometer to control the potential within a predetermined range. The reaction is stirred for 1-2 hours, so that the organic sulfur compound slowly releases active sulfur, which reacts with rhenium to form a sulfur-rhenium compound precipitate, thereby achieving rhenium enrichment.

[0013] Preferably, the potential is controlled within the range of 0.18-0.21V.

[0014] The beneficial effects of the present invention are:

[0015] Compared with the prior art, the organic sulfur compound used in the present invention as a precipitant can slowly release active sulfur in a polluted acidic environment, thereby achieving selective precipitation of rhenium, avoiding the problem that traditional precipitants are difficult to function in an acidic environment, and improving the enrichment efficiency of rhenium. DETAILED DESCRIPTION

[0016] The present invention is further described below with reference to the embodiments.

[0017] A method for recovering rhenium from copper smelting waste acid specifically comprises the following steps:

[0018] Step 1: Synthesis of organosulfur compounds; using unsaturated hydrocarbon compounds containing double bonds (such as acrylates, methacrylates, etc.), thiol-containing compounds (such as mercaptoethanol, thioglycolic acid, etc.) and initiators (such as azobisisobutyronitrile) as synthesis raw materials.

[0019] An unsaturated hydrocarbon compound and a thiol-containing compound are added to a reaction vessel at a molar ratio of 1:1-1.5. The thiol (-SH) group in the thiol-containing compound reacts with the carbon-carbon double bond in the acrylate compound to undergo an addition reaction. Due to certain reversibility and other competing reactions, the reaction cannot proceed completely. Increasing the amount of the thiol-containing compound can allow as many acrylate compounds as possible to participate in the reaction, thereby improving the conversion rate of the reaction and converting more acrylate compounds into the target product, thereby improving the yield of the product.

[0020] An appropriate amount of initiator (accounting for 0.5-2% of the total mass of the reactants) is added, and the reaction is stirred at 60-80° C. for 3-5 hours under nitrogen protection to obtain an organic sulfur compound.

[0021] Azobisisobutyronitrile begins to decompose and generate free radicals at about 60-80°C. The decomposition rate is moderate and can effectively initiate the polymerization reaction. If the temperature is too low, the rate of decomposition of azobisisobutyronitrile to generate free radicals is too slow, the initiation efficiency is low, and the polymerization reaction is difficult to proceed. If the temperature is too high, azobisisobutyronitrile decomposes too quickly and the concentration of generated free radicals is too high, resulting in a runaway reaction and an increase in side reactions. The reaction time is controlled to be 3-5 hours. As the reaction time increases, the conversion rate gradually increases. After the reaction reaches a certain time, the conversion rate tends to stabilize.

[0022] Taking the reaction of methyl acrylate and mercaptoethanol as an example, the molecular formula of the synthesized organic sulfur compound is C5H 12 O3S, whose structure contains an ester group (-COO-) and a sulfide bond (-S-), has the simplified structural formula HOCH2CH2SCH2CH2COOCH3. The molecular structure of the organosulfur compound can be adjusted by varying the type and ratio of the unsaturated hydrocarbon compound and the sulfhydryl-containing compound.

[0023] The sulfide bond (-S-) in the organic sulfur compound molecule is an active group. Since the sulfur atom in the sulfide bond has a relatively low electronegativity and contains a lone pair of electrons, it has a strong nucleophilicity. At the same time, groups such as the ester group in the molecule make the organic sulfur compound have a certain stability in the acidic environment of polluted acid, and can slowly hydrolyze and then slowly release active sulfur.

[0024] Organic sulfur compounds containing sulfide bonds have unique selectivity for rhenium metal ions. Their sulfide bonds can form stable complexes with rhenium ions, while the stability of complexes with other metal ions such as copper, lead, arsenic, etc. is poor, thereby achieving selective precipitation of rhenium.

[0025] Organosulfur compounds containing thioether bonds slowly release active sulfur, which can maintain an appropriate sulfur ion concentration in the solution for a long time, allowing rhenium ions to fully react with sulfur ions to form a precipitate. This slow release characteristic can avoid the problem of small precipitate particles or incomplete precipitation caused by excessive local sulfur ion concentration. Therefore, organosulfur compounds containing thioether bonds have a better precipitation effect when precipitating rhenium metal ions, and the purity and recovery rate of the precipitate are also higher.

[0026] Organic sulfur compounds containing sulfide bonds generally have low toxicity and good biodegradability, and have relatively little impact on the environment. In the process of precipitating rhenium metal ions, organic sulfur compounds containing sulfide bonds that slowly release active sulfur selectively target rhenium for precipitation while copper, lead, arsenic, etc. are not precipitated. Different metal ions react with sulfur ions at different redox potentials. Through potential control, the system potential can be maintained within a range that allows rhenium ions to preferentially react with active sulfur to form precipitates, while copper, lead, arsenic, etc. ions continue to remain in the solution because the potential does not meet their precipitation requirements. The sulfide solubility product of rhenium is relatively small. Organic sulfur compounds slowly release active sulfur, which can maintain the sulfur ion concentration in the solution at a specific level relatively stably. This helps to more accurately control the redox potential, keeping it within a range that only allows rhenium ions to preferentially react with active sulfur to form precipitates, avoiding potential fluctuations caused by instantaneous changes in sulfur ion concentration, thereby improving the selectivity of rhenium ion precipitation. The addition of commonly used inorganic sulfur-containing precipitants such as sodium sulfide and sodium thiosulfate may cause the sulfur ion concentration in the solution to change rapidly, making it more difficult to accurately control the potential.

[0027] Combined with the potential control of the precipitation process, under the same conditions, when the sulfur ion concentration in the solution reaches a certain level, rhenium ions are more likely to combine with sulfur ions to form a precipitate; in contrast, the sulfide solubility product of metal ions such as copper, lead, and arsenic is relatively large, which means that under the condition of slow release of active sulfur, the sulfur ion concentration in the solution is not enough to make metal ions such as copper, lead, and arsenic reach their solubility product and form a precipitate.

[0028] The presence of an ester group in the organosulfur compound molecule controls the hydrolysis rate of the organosulfur compound. Since ester hydrolysis is a relatively slow process, it gradually dissociates the portion connected to the ester group from the organosulfur compound molecule, thereby indirectly controlling the release rate of active sulfur. Compared with similar compounds without ester groups, organosulfur compounds containing ester groups can avoid the rapid release of active sulfur, achieving a slow and continuous sulfur release process, which is conducive to the full reaction of rhenium ions and sulfur ions to form a precipitate, improving the precipitation effect and the quality of the precipitate. The hydrolysis of the ester group produces intermediates containing hydroxyl groups or other nucleophilic groups, which have a certain impact on the thioether bond, prompting the thioether bond to break, thereby allowing the sulfur atom originally connected to the thioether bond to become active sulfur, which combines with rhenium ions in the solution to form a precipitate.

[0029] Step 2: precipitation and enrichment: adding the synthesized organic sulfur compound as a precipitant to the copper smelting waste acid, the amount of the precipitant added is 1.2-1.5 times the theoretical amount of rhenium precipitation in the waste acid,

[0030] A moderate excess of an organosulfur compound precipitant is beneficial for improving the precipitation rate. As the excess coefficient increases, the concentration of active sulfur in the solution gradually rises, increasing the probability of collision with rhenium metal ions. More rhenium ions can combine with active sulfur to form a precipitate, thereby increasing the precipitation rate. However, an excessively large excess coefficient does not significantly improve the precipitation rate. When the excess coefficient exceeds a certain value, further increasing the amount of precipitant will result in a significant increase in the effective collision probability between active sulfur and rhenium ions, as the rhenium ion concentration is too low. Consequently, further additions to the precipitant will not significantly improve the precipitation rate.

[0031] While adding the precipitant, an appropriate amount of oxygen or air is introduced into the waste acid, and the potential of the solution is monitored in real time using a potentiometer to control the potential within the range of 0.18-0.21V. The reaction is stirred for 1-2 hours, so that the organic sulfur compound slowly releases active sulfur, which reacts with rhenium to form a sulfur-rhenium compound precipitate, thereby achieving rhenium enrichment.

[0032] In the early stages of the precipitation reaction, due to the slow release of active sulfur, the active sulfur concentration in the solution is low, and the reaction rate with rhenium ions is relatively slow. Rhenium ions gradually combine with the slowly released active sulfur to form crystal nuclei, but the number of crystal nuclei formed is relatively small. Over time, the organic sulfur continues to slowly release active sulfur, the active sulfur concentration in the solution gradually increases, and the reaction rate with rhenium ions accelerates. The crystal nuclei continue to grow, and new crystal nuclei are constantly formed. The amount of precipitation gradually increases, and the rate of decrease in rhenium ion concentration accelerates. After the reaction has proceeded for a certain period of time, the metal ion concentration in the solution decreases significantly, and the amount of active sulfur released also gradually decreases. At this point, the precipitation reaction is mainly a process of further growth of crystal nuclei and aging of the precipitate.

[0033] The particles of the precipitate gradually become larger, the structure more stable, and the precipitation effect gradually stabilizes. As time goes on, the precipitation rate generally increases; in the early stages of the reaction, the precipitation rate rises slowly; in the middle stages of the reaction, the precipitation rate rises rapidly; in the late stages of the reaction, the rate of increase gradually slows and eventually stabilizes. However, if the reaction time is too long, on the one hand, it may cause the precipitate to redissolve; on the other hand, too long a reaction time will increase processing costs and reduce production efficiency.

[0034] In an acidic environment, the sulfide bond (-S-) in the organic sulfur compound molecule undergoes hydrolysis reaction, gradually hydrolyzing and releasing active sulfur. Since rhenium is mainly present in the solution as perrhenate ion (ReO4 -), and the active sulfur has a strong nucleophilicity and can undergo redox and coordination reactions with the perrhenate ion.

[0035] From a redox perspective, under controlled potential conditions (0.18-0.21V), active sulfur is oxidized, increasing the valence of the sulfur element while decreasing the valence of the rhenium element in the perrhenate ion. During the reaction, the active sulfur loses electrons and is oxidized to disulfide bonds (-SS-), while the perrhenate ion gains electrons, reducing the rhenium element from a valence of +7 to a lower valence state, such as +4.

[0036] From the perspective of coordination reactions, the reduced rhenium ions bind to the sulfur atoms in the active sulfur through coordination bonds, forming stable sulfur-rhenium compounds. As the reaction proceeds, these sulfur-rhenium compounds aggregate and form precipitates that precipitate from the solution, thereby enriching rhenium. Potential control plays a key role in this process. A suitable potential ensures smooth redox and coordination reactions between the active sulfur and perrhenate ions, promoting the formation of the sulfur-rhenium compound precipitate.

[0037] Step 3: solid-liquid separation; the precipitated solution is subjected to solid-liquid separation by filtration or centrifugation to obtain rhenium-rich slag and the separated solution.

[0038] Step 4: Subsequent treatment: washing, drying and other treatments are performed on the rhenium-rich slag to facilitate subsequent extraction of rhenium metal.

[0039] The organic sulfur compound used in the present invention as a precipitant can slowly release active sulfur in a polluted acidic environment to achieve selective precipitation of rhenium, avoid the problem that traditional precipitants are difficult to function in an acidic environment, and improve the enrichment efficiency of rhenium.

[0040] By controlling the potential to regulate the precipitation conditions, the precipitation reaction process was further optimized, making the precipitation reaction more complete. The obtained rhenium-rich slag contained 2-3% rhenium, effectively improving the rhenium recovery efficiency.

[0041] The method is simple to operate and has low cost. The organic sulfur compounds are relatively environmentally friendly, reducing secondary pollution and having good economic and environmental benefits.

[0042] The present invention is further described below with reference to specific embodiments.

[0043] Example 1

[0044] 1. Synthesis of organosulfur compounds:

[0045] Instrument and Reagent Preparation: Use a 500mL four-necked flask as the reaction vessel, equipped with an electric stirrer, a spherical condenser, a thermometer, and a nitrogen inlet. Accurately weigh 1 mol (100 g) of methyl acrylate and 1.2 mol (87.6 g) of mercaptoethanol, both of analytical grade, and add them to the four-necked flask. Weigh 0.01 mol (1.64 g) of azobisisobutyronitrile as the initiator and slowly add it to the flask. Gently stir with a glass rod to ensure that the initiator is initially dispersed throughout the reactants.

[0046] Reaction process: high-purity nitrogen gas was introduced into the four-necked flask to exhaust the air in the device and prevent the reactants from being oxidized. The ventilation time lasted for 10 minutes; the electric stirrer was turned on and the stirring speed was set to 300 r / min to fully mix the reactants; the reaction system was heated in an oil bath, the temperature was gradually raised to 70°C, and the temperature was maintained; during the reaction, the volatilized reactants were condensed and refluxed through a spherical condenser to ensure that the reaction was carried out in a closed system; the reaction lasted for 4 hours, during which the solution was observed to gradually change from colorless and transparent to light yellow, indicating that the reaction was in progress.

[0047] Product treatment: After the reaction is completed, stop heating and stirring, and wait for the reaction system to cool naturally to room temperature; transfer the reacted solution to a separatory funnel, add an equal volume of petroleum ether for extraction, and shake the separatory funnel for 5 minutes to separate the product from the unreacted raw material as much as possible; after standing and stratification, collect the lower organic phase, place it on a rotary evaporator, and evaporate the petroleum ether at 40°C under reduced pressure to obtain a light yellow viscous organic sulfur compound.

[0048] 2. Precipitation and enrichment:

[0049] Raw material preparation: Take 1L of copper smelting waste acid containing 10mg / L rhenium. This waste acid is obtained from the actual production process of a copper smelter. Its main components include sulfuric acid (concentration is about 0.5mol / L) and small amounts of metal ions such as copper, lead, and arsenic. Pour the waste acid into a 2L glass beaker, place it on a magnetic stirrer, and add a stirring magnet.

[0050] Precipitation procedure: Calculate the theoretical precipitate based on the rhenium content. Weigh 1.3 times the theoretical precipitate amount of the synthesized organosulfur compound and slowly add it to the waste acid. Simultaneously, connect an air aeration system and introduce air into the waste acid at a rate of 100 mL / min, adjusting the solution potential via the redox reaction. Insert a platinum electrode and a calomel electrode into the waste acid solution and connect them to a potentiometer to monitor the solution potential in real time. Start a magnetic stirrer at 400 rpm to ensure thorough mixing of the precipitant and waste acid. Maintain a stable potential of 0.2 V by controlling the air flow rate. Stir the reaction for 1.5 hours. During the reaction, a black precipitate gradually appears in the solution, indicating the beginning of rhenium accumulation. The rhenium content in the post-precipitation solution was assayed, revealing a rhenium precipitation rate of 99.3%.

[0051] 3. Solid-Liquid Separation: Use a vacuum filtration device for solid-liquid separation. Place a quantitative filter paper in a Büchner funnel and moisten the filter paper with a small amount of distilled water so that it adheres closely to the inner wall of the funnel. Pour the precipitated solution into the Büchner funnel and start the vacuum pump for filtration. After the solution is completely filtered, wash the filter residue with a small amount of deionized water three times, using 20 mL of water each time, to remove impurity ions attached to the surface of the rhenium-rich slag. After filtration, carefully remove the rhenium-rich slag from the Büchner funnel and place it on a watch glass.

[0052] 4. Subsequent Processing: The rhenium-rich slag on the watch glass was placed in a forced air drying oven at 80°C for 12 hours. After drying, the rhenium-rich slag was ground into a powder and its rhenium content was measured using an inductively coupled plasma mass spectrometer (ICP-MS). The test results showed a rhenium content of 2.2%.

[0053] Example 2

[0054] 1. Synthesis of organosulfur compounds:

[0055] Preparation of instruments and reagents: Select a 1000 mL four-necked flask as the reaction vessel, install an electric stirrer, a spherical condenser, a thermometer, and a nitrogen inlet device; accurately measure 1 mol (116 g) of ethyl methacrylate and 1.1 mol (80.3 g) of thioglycolic acid, both chemically pure reagents, and add them to the four-necked flask; weigh 0.015 mol (2.46 g) of azobisisobutyronitrile as an initiator, pour it into the flask, and shake gently to disperse the initiator.

[0056] Reaction process: Nitrogen was introduced into the four-necked flask for 15 minutes to expel all air from the apparatus. An electric stirrer was activated at 350 rpm to ensure uniform mixing of the reactants. The reaction system was heated in a water bath to 65°C and maintained at this temperature. During the reaction, reflux was maintained through a spherical condenser to prevent evaporation of the reactants. The reaction lasted for 4.5 hours, during which time the solution color gradually darkened to light brown.

[0057] Product treatment: After the reaction is completed, stop heating and stirring, and wait for the solution to cool to room temperature; transfer the reaction solution to a separatory funnel, add 2 volumes of dichloromethane for extraction, shake for 10 minutes, let it stand and separate, and collect the lower organic phase; place the organic phase on a rotary evaporator and remove dichloromethane at 35°C under reduced pressure to obtain a brown viscous organosulfur compound.

[0058] 2. Precipitation and enrichment:

[0059] Raw material preparation: Take 1.5 L of copper smelting waste acid containing 12 mg / L rhenium. The sulfuric acid concentration of this waste acid is approximately 0.8 mol / L and contains impurities such as copper, arsenic, and cadmium. Pour the waste acid into a 3 L glass beaker and place it on a magnetic stirrer with a magnetic stirrer.

[0060] Precipitation Procedure: Calculate the theoretical precipitation amount based on the rhenium content. Weigh the synthesized organosulfur compound at 1.4 times the theoretical precipitation amount and slowly add it to the waste acid. Connect an oxygen inlet device and introduce oxygen into the waste acid at a flow rate of 80 mL / min. Simultaneously, connect a platinum electrode and a calomel electrode to a potentiometer to monitor the solution potential in real time. Turn on a magnetic stirrer at a stirring speed of 450 rpm to ensure full contact between the precipitant and the waste acid. Adjust the oxygen inlet to maintain the potential at 0.18 V, and stir the reaction for 1.8 hours. During the reaction, a large amount of black precipitate forms in the solution. After precipitation, the rhenium content in the solution is assayed, revealing a rhenium precipitation rate of 99.5%.

[0061] 3. Solid-liquid separation: Use centrifugal separation. Transfer the precipitated solution to a 50mL centrifuge tube and place it symmetrically in a centrifuge. Set the centrifugal speed to 5000r / min and the centrifugation time to 10 minutes. After centrifugation, carefully remove the supernatant with a pipette, leaving the rhenium-rich slag precipitate at the bottom. Wash the rhenium-rich slag with a small amount of dilute sulfuric acid (0.1mol / L) twice, centrifuging after each wash to remove impurities.

[0062] 4. Subsequent Processing: The washed rhenium-rich slag was placed in a vacuum drying oven at 70°C and a vacuum of -0.08 MPa for 15 hours. After drying, the rhenium-rich slag was ground uniformly and its rhenium content was measured using an inductively coupled plasma mass spectrometer (ICP-MS). The results showed a rhenium content of 2.5%.

[0063] Example 3

[0064] 1. Synthesis of organosulfur compounds:

[0065] Instrument and Reagent Preparation: Use a 500mL four-necked flask equipped with stirring, condensing, temperature measurement, and nitrogen flow. Accurately weigh 1 mol (128g) of butyl acrylate and 1.3 mol (95.8g) of mercaptoethanol (both analytical grade). Weigh 0.012 mol (1.97g) of azobisisobutyronitrile as an initiator and add them to the four-necked flask. Stir to mix thoroughly.

[0066] Reaction process: Nitrogen was introduced into the four-necked flask for 12 minutes, and air was expelled. Stirring was started at 280 rpm, and the reaction temperature was raised to 75°C in an oil bath. The reaction was continued for 3.5 hours. During the reaction, the solution gradually became clear and transparent, with a slight pungent odor.

[0067] Product Workup: After the reaction is complete and cooled, the solution was transferred to a separatory funnel and extracted with an equal volume of ethyl acetate. The mixture was shaken for 8 minutes, and the lower organic phase was collected after stratification. The ethyl acetate was removed on a rotary evaporator at 45°C under reduced pressure to yield a colorless, transparent organosulfur compound.

[0068] 2. Precipitation and enrichment:

[0069] Raw material preparation: Take 2L of copper smelting waste acid containing 8mg / L rhenium and approximately 0.7mol / L sulfuric acid, which also contains impurities such as copper, zinc, and lead. Pour the waste acid into a 4L glass beaker and place it on a magnetic stirrer with a magnetic stirrer.

[0070] Precipitation Procedure: Weigh 1.2 times the theoretical amount of rhenium to be precipitated from the synthesized organosulfur compound and add it to the waste acid. Connect an air aeration device and introduce air at a flow rate of 120 mL / min while monitoring the potential. Start magnetic stirring at 380 rpm and control the potential at 0.21 V. Stir and react for 1.2 hours until a black precipitate appears in the solution. After precipitation, the rhenium content in the solution is assayed, revealing a rhenium precipitation yield of 99.2%.

[0071] 3. Solid-Liquid Separation: Use a vacuum filtration device for solid-liquid separation. Place a quantitative filter paper in a Büchner funnel and moisten the filter paper with a small amount of distilled water, ensuring it adheres tightly to the inner wall of the funnel. Pour the precipitated solution into the Büchner funnel and start the vacuum pump for filtration. After the solution has been completely filtered, wash the filter residue with a small amount of deionized water four times, using 50 mL of water each time, to remove impurity ions adhering to the surface of the rhenium-rich slag. After filtration, carefully remove the rhenium-rich slag from the Büchner funnel and place it on a watch glass.

[0072] 4. Subsequent treatment: The washed filter cake was placed in a drying oven at 85° C. and dried for 10 hours. After drying, the filter cake was ground into powder and its rhenium content was detected by inductively coupled plasma mass spectrometry (ICP-MS). The results showed that the rhenium content was 2.1%.

[0073] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for recovering rhenium from copper smelting waste acid, characterized in that: The steps include: S1. Synthesize organic sulfur compounds, which slowly release active sulfur in an acidic environment; S2. Adding the synthesized organic sulfur compound as a precipitant to the copper smelting waste acid, causing the organic sulfur compound to slowly release active sulfur, which reacts with rhenium to form a sulfur-rhenium compound precipitate, thereby achieving rhenium enrichment; S3, performing solid-liquid separation on the precipitated solution to obtain rhenium-rich slag and a separated solution; S4. Washing and drying the rhenium-rich slag to further extract rhenium metal.

2. The method for recovering rhenium from copper smelting waste acid according to claim 1, wherein: In step S1, an unsaturated hydrocarbon compound containing a double bond, a compound containing a thiol group, and an initiator are used as synthetic raw materials to form an organic sulfur compound containing a thioether bond.

3. The method for recovering rhenium from copper smelting waste acid according to claim 2, characterized in that: The unsaturated hydrocarbon compound and the thiol-containing compound are added to a reaction vessel in a molar ratio of 1:1-1.5, and an appropriate amount of initiator is added. Under nitrogen protection, the mixture is stirred and reacted at a temperature of 60-80° C. for 3-5 hours to obtain an organic sulfur compound.

4. The method for recovering rhenium from copper smelting waste acid according to claim 3, wherein: The initiator accounts for 0.5-2% of the total mass of the reactants.

5. The method for recovering rhenium from copper smelting waste acid according to claim 1, characterized in that: The amount of the precipitant added in step S2 is 1.2-1.5 times the theoretical amount of rhenium precipitated in the waste acid.

6. The method for recovering rhenium from copper smelting waste acid according to claim 1, characterized in that: While adding the precipitant, an appropriate amount of oxygen or air is introduced into the waste acid, and the potential of the solution is monitored in real time using a potentiometer to control the potential within a predetermined range. The reaction is stirred for 1-2 hours, so that the organic sulfur compound slowly releases active sulfur, which reacts with rhenium to form a sulfur-rhenium compound precipitate, thereby achieving rhenium enrichment.

7. The method for recovering rhenium from copper smelting waste acid according to claim 6, characterized in that: The potential was controlled in the range of 0.18-0.21V.