A method and apparatus for recovering copper from spent ionic liquids

Abstract

This invention provides an apparatus for recovering copper from waste ionic liquids, comprising: a displacement reactor and a sedimentation tank. The displacement reactor includes, from bottom to top, a water and gas distribution zone, a displacement reaction zone, a three-phase separation zone, and an effluent zone, all connected sequentially. The effluent zone surrounds the upper part of the three-phase separation zone. The water and gas distribution zone is provided with a reactor inlet and a reactor gas inlet. The displacement reaction zone includes, from bottom to top, a support layer and an aluminum particle layer. The three-phase separation zone is provided with a three-phase separator, the aqueous phase outlet of which is connected to the effluent zone. The effluent zone is connected to the sedimentation tank, and the sedimentation tank is provided with a sedimentation tank outlet, a circulating water outlet, and a sedimentation outlet at its upper, middle, and bottom parts, respectively. This invention also provides a method for recovering copper from waste ionic liquids. This apparatus is space-saving, has a high copper displacement recovery rate, strong shock resistance, and can effectively recover copper resources and reduce wastewater treatment costs, showing broad application prospects.

Description

Technical Field

[0001] This invention belongs to the fields of chemical and environmental protection technology, and relates to a method and apparatus for recovering copper from waste ionic liquids, and more particularly to a method and apparatus for recovering copper from waste ionic liquids from oil alkylation. Background Technology

[0002] The tightening of environmental standards in my country has made upgrading fuel quality an inevitable choice. C4 catalytic alkylation is a crucial process for producing clean, high-octane gasoline blending components (i.e., alkylated oil). New alkylation processes using composite ionic liquids as catalysts are increasingly being adopted in newly built alkylation plants. The main components of the composite ionic liquid catalyst are anhydrous aluminum chloride (AlCl3), triethylamine hydrochloride (Et3NHCl), and transition metal salts (such as CuCl2). During the alkylation reaction, acidic waste ionic liquid is periodically generated due to catalyst deactivation. This waste ionic liquid contains a high concentration of copper ions. Fully recovering and utilizing these copper ions would reduce waste emissions and bring economic benefits, making the development of suitable copper recovery methods particularly necessary.

[0003] The main methods for recovering copper from acidic copper-containing solutions include electrolysis, solvent extraction, and displacement. While electrolysis can recover the effective components, its application is limited by the release of chlorine gas during the process. Solvent extraction is difficult to apply due to the high acidity of the solution and the difficulty in finding suitable extractants. Displacement has become the widely used mainstream method.

[0004] Since the ionic liquid alkylation process generates a large amount of waste ionic liquid, there is an urgent need to develop a method and apparatus for recovering copper from the waste ionic liquid of oil alkylation, in order to recover valuable resources and reduce waste treatment costs. Summary of the Invention

[0005] To address the problems existing in the prior art, this invention provides an apparatus and method for recovering copper from waste ionic liquids, especially oil alkylation waste ionic liquids. This apparatus exhibits a high copper ion replacement rate, good stability and safety, overcoming the shortcomings of existing technologies while also recovering valuable copper resources, reducing the amount of hazardous solid waste generated from waste ionic liquids, and lowering treatment and operating costs. This method and apparatus can achieve a copper recovery rate of over 90% when treating waste ionic liquids.

[0006] To achieve the above objectives, in a first aspect, the present invention provides an apparatus for recovering copper from waste ionic liquid, comprising: a displacement reactor and a sedimentation tank; the displacement reactor comprising, from bottom to top, a water distribution and gas distribution zone, a displacement reaction zone, a three-phase separation zone, and an effluent zone connected in sequence; the effluent zone surrounds the upper part of the three-phase separation zone; the water distribution and gas distribution zone is provided with a reactor inlet and a reactor gas inlet; the displacement reaction zone comprises, from bottom to top, a support layer and an aluminum particle layer; the three-phase separation zone is provided with a three-phase separator; the aqueous phase outlet of the three-phase separator is connected to the effluent zone; the effluent zone is connected to the sedimentation tank; the sedimentation tank is provided with a sedimentation tank outlet, a circulating water outlet, and a sedimentation collection outlet at its upper, middle, and bottom parts, respectively.

[0007] As a specific embodiment of the present invention, preferably, the displacement reactor is an expanded bed displacement reactor; and / or the water and gas distribution zone includes interconnected water distribution zone and gas distribution zone from bottom to top, more preferably, the water distribution zone is provided with a water distribution pipe and a support distribution plate, and / or the gas distribution zone is provided with a gas distribution pipe; even more preferably, the support distribution plate is provided with uniformly arranged perforations, the diameter of the perforations being smaller than the pore diameter of the support layer; and / or the water and gas distribution zone is also provided with a reactor discharge inspection port, more preferably, the discharge inspection port is located above the gas distribution pipe.

[0008] In a preferred embodiment of the present invention, the three-phase separator includes a central tube and a funnel-shaped cover, with the flared end of the cover facing downwards. One end of the central tube communicates with the constricted end of the cover, and the other end extends out of the device. The water phase outlet is disposed on the cover. More preferably, the cover is composed of an upper cover, a lower cover, and a connector. The connector supports the overlapping portions of the upper and lower covers to form a flow channel, i.e., the water phase outlet. And / or a water collection tank is provided at the top of the water outlet area, and the water collection tank is provided with a reactor outlet communicating with the sedimentation tank. And / or a filter screen is provided on the circulating water outlet.

[0009] In a specific embodiment of the present invention, preferably, the height-to-diameter ratio of the displacement reactor is 5:1-8:1; and / or the particle size of the aluminum particles in the aluminum particle layer is 0.5-2 mm; and / or the volume ratio of the aluminum particles in the displacement reaction zone is 20-80%; and / or the displacement reaction zone is provided with an aluminum particle feeding port above the aluminum particle layer.

[0010] Specifically, the device has a large height-to-diameter ratio, saves space, has a compact structure, and a high copper ion replacement rate.

[0011] In a preferred embodiment of the present invention, the apparatus further includes a digestion reactor and an oil removal device connected in series. The digestion reactor is used to receive waste ionic liquid and digest it. The oil removal device is used to receive the digested material and remove oil from it. The outlet of the oil removal device is connected to the inlet of the reactor. More preferably, the digestion reactor is a fully mixed reactor, and / or the oil removal device is selected from at least one of an oil separator, an oil settling tank, and an oil separator. The apparatus further includes a feed pump, a circulation pump, and an air pump. The feed pump is located between the oil removal device and the inlet of the reactor. The circulation pump is located between the outlet of the circulating water and the inlet of the reactor. The air pump is connected to the air inlet of the reactor.

[0012] As a specific embodiment of the present invention, preferably, the oil separator is an inclined plate oil separator, and / or the oil remover is a ceramic membrane oil remover, and more preferably, the ceramic membrane pore size in the ceramic membrane oil remover is 0.05-0.2μm.

[0013] Specifically, an inclined plate oil separator can be composed of a horizontal flow sedimentation tank with an added inclined plate.

[0014] Specifically, the treatment process of the deoiling and digestion solution obtained by pretreatment of the oil alkylation waste ionic liquid described in this invention in the device is as follows:

[0015] After pretreatment, the waste ionic liquid is stored in a feed tank connected to a feed pump. Simultaneously, a portion of the supernatant from the sedimentation tank, filtered through a screen, enters the circulating water pump from the outlet. The mixture of the feed pump and circulating water enters the displacement reactor through the reactor inlet at the bottom. The water flow is first distributed through a distribution pipe and then further distributed through a support plate. Simultaneously, an air pump blows air or nitrogen into the displacement reactor through the inlet. After being distributed through the distribution pipe, the air or nitrogen mixes with the water-distributed mixture from the support plate, forming a gas-containing mixture. This gas-containing mixture enters the displacement reaction zone, passes through the support layer, and then enters the aluminum particle layer. In the gas-containing mixture, copper ions undergo a displacement reaction with aluminum particles to generate elemental copper. Under the upward flow of water / air, the aluminum particles in the aluminum particle layer are in an expanded state. Furthermore, under the disturbance of the water / air flow, the elemental copper generated by the displacement reaction exists in the form of flocs, i.e., copper flocs. After passing through the aluminum particle layer, the gas-containing mixture forms a mixture containing copper flocs. It continues to flow upward to the three-phase separation zone. After separation by the three-phase separator, the air is discharged from the central tube of the three-phase separator, and the aluminum particles carried up by the water / air flow fall back into the displacement reaction zone. The mixture containing copper flocs enters the effluent zone from the aqueous phase outlet. In the effluent zone, the mixture containing copper flocs enters the water collection tank and flows out of the displacement reactor from the reactor outlet, then enters the sedimentation tank through the sedimentation tank inlet.

[0016] In the settling tank, the copper flocs in the mixed liquid containing copper flocs settle to the bottom of the settling tank, forming copper precipitate, which can be collected from the settling outlet at regular intervals. Part of the supernatant is discharged from the settling tank outlet for further treatment, and part of the supernatant is filtered through a filter screen and enters the circulating pump from the circulating water outlet to complete the circulation process of the supernatant. During the above process, aluminum particles can be added into the expanded bed replacement reactor through the aluminum particle feeding port, and the material can also be discharged from the reactor through the unloading inspection port.

[0017] In addition, the interior of the expanded bed replacement reactor can be inspected periodically or when a malfunction occurs through the unloading inspection port.

[0018] To achieve the above objective, in a second aspect, the present invention provides a method for recovering copper from waste ionic liquids, using the aforementioned apparatus, comprising the following steps:

[0019] Step 1, Pretreatment, includes: digesting the waste ionic liquid to eliminate its activity, and then performing degreasing treatment to obtain a degreased digestion solution;

[0020] Step 2, gas-liquid mixing, includes: the oil removal and digestion solution is mixed with circulating water and enters the water and gas distribution zone, and mixes with the gas in the water and gas distribution zone to form a gas-containing mixture;

[0021] Step 3, replacement, includes: the gas-containing mixture enters the replacement reaction zone, where copper ions react with aluminum particles in the aluminum particle layer to generate elemental copper. Under the action of upward flowing water / gas, elemental copper is generated as copper flocs, and the gas-containing mixture becomes a mixture containing copper flocs. The aluminum particles are in an expanded state, and some of the aluminum particles enter the three-phase separation zone with the mixture containing copper flocs.

[0022] Step 4, three-phase separation, includes: separation in the three-phase separation zone, gas discharge device in the copper-containing flocculent mixture, aluminum particles falling back into the displacement reaction zone, and the copper-containing flocculent mixture entering the sedimentation tank via the effluent zone;

[0023] Step 5, sedimentation, includes: the mixed liquid containing copper flocs settles in the sedimentation tank to obtain bottom copper precipitate and supernatant. The copper precipitate is collected from the sedimentation outlet, and part of the supernatant is used as circulating water and part is discharged from the device.

[0024] As a specific embodiment of the present invention, preferably, the preprocessing includes the following steps:

[0025] The first step involves mixing the waste ionic liquid with concentrated brine and carrying out a digestion reaction until the activity of the waste ionic liquid is eliminated, resulting in an acidic digestion solution.

[0026] The second step is to degrease the acidic digestion solution in an oil removal device to obtain an oil-removed digestion solution.

[0027] Specifically, the oil removal equipment consists of an inclined plate oil separator and a ceramic membrane oil separator. The residence time of the acidic digestion solution in the oil separator is preferably not less than 6 hours, and the oil content in the effluent is less than 50 mg / L. The pore size of the ceramic membrane in the ceramic membrane oil separator is preferably 0.05-0.2 μm, and the oil content in the effluent is less than 5 mg / L. The copper concentration in the obtained oil removal digestion solution is 1000-2000 mg / L.

[0028] As a specific embodiment of the present invention, preferably, the waste ionic liquid is an oil alkylation waste ionic liquid; more preferably, the waste ionic liquid is a waste ionic liquid generated from the catalytic production of alkylated oil from C4 using aluminochloroaluminate ionic liquid; and even more preferably, the waste ionic liquid includes transition metal salt compounds. Specifically, the active component of the waste ionic liquid is a complex formed by triethylamine hydrochloride, aluminum chloride, and copper chloride, and the other components are mainly acid-soluble oils.

[0029] As a specific embodiment of the present invention, preferably, the digestion in step 1 uses concentrated brine with a sodium chloride concentration of 15-25 wt%, the feed volume ratio of the waste ionic liquid to the concentrated brine is preferably 1:(45-60), and / or the pH of the digestion solution obtained by digestion is 2.5-4.

[0030] In a specific embodiment of the present invention, preferably, the copper concentration in the degreasing and digestion solution in step 2 is 1000-2000 mg / L, and the oil content is less than 5 mg / L; and / or the ventilation intensity of the gas introduced into the water and gas distribution zone is 10-90 L / m. 2 / s; and / or the gas is selected from nitrogen or air.

[0031] In a specific embodiment of the present invention, preferably, the upflow velocity in the displacement reactor is 30-120 m / h, the feed residence time is 20-40 min; and / or the residence time of the copper-containing flocculent mixture in the sedimentation tank is not less than 30 min, and the copper concentration in the supernatant is less than 15 mg / L.

[0032] The beneficial effects of this invention are as follows:

[0033] (1) Using small aluminum particles (with an outer diameter of 0.5 mm to 2 mm) as the replacement material, which has a large specific surface area, can effectively increase the copper replacement amount per unit volume of aluminum and increase the copper replacement load of the reactor.

[0034] (2) The aluminum particle layer is in an expanded state during normal operation, which can avoid water flow short circuit that may occur in the fixed bed. The flow state of the solid and liquid phases is conducive to the contact and mass transfer between aluminum particles and copper-containing wastewater, and improves the efficiency of the displacement reaction.

[0035] (3) The three-phase separator can greatly reduce the possibility of aluminum particles being carried out of the reactor under the action of water / air flow, effectively avoiding the loss of aluminum particles;

[0036] (4) Using a copper flocculent sedimentation tank can result in high purity copper precipitate products;

[0037] (5) The expanded bed displacement reactor has a large height-to-diameter ratio, a small footprint, high copper displacement efficiency, strong shock resistance, short residence time, and simple operation. It can effectively recover copper resources and reduce wastewater treatment costs, and has broad application prospects. Attached Figure Description

[0038] Figure 1 This is a schematic diagram of an apparatus for recovering copper from alkylation waste ionic liquid of oil, provided by the present invention.

[0039] Explanation of reference numerals in the attached figures:

[0040] 1. Expanded bed displacement reactor; 2. Reactor inlet; 3. Water distribution pipe; 4. Reactor air inlet; 5. Air distribution pipe; 6. Support distribution plate; 7. Support layer; 8. Aluminum granule layer; 9. Aluminum granule feed port; 10. Three-phase separator; 11. Water collection tank; 12. Reactor outlet; 13. Sedimentation tank; 14. Sedimentation tank inlet; 15. Sedimentation tank outlet; 16. Circulating water outlet; 17. Filter screen; 18. Sedimentation outlet; 19. Feed tank; 20. Feed pump; 21. Circulation pump; 22. Air pump; 23. Unloading and maintenance port. Detailed Implementation

[0041] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0042] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0043] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0044] In the description of this invention, it should be understood that the terms "upper," "lower," "inner," "outer," "left," and "right," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this invention is in use, or the orientation or positional relationship commonly understood by those skilled in the art. They are used only for the convenience of describing this invention and for simplifying the description, and do not 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. Furthermore, the terms "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance. In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, terms such as "set" and "connect" should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0045] See Figure 1 As shown, Figure 1This is a schematic diagram of the apparatus for recovering copper from waste ionic liquid according to the present invention. The apparatus for recovering copper from waste ionic liquid provided by the present invention includes: an expanded bed displacement reactor 1 and a sedimentation tank 13. The expanded bed displacement reactor 1 is a cylindrical structure with a circular cross-section, placed vertically, and can be made of steel or other alloy materials. The expanded bed displacement reactor 1 includes, from bottom to top, a water distribution and gas distribution zone, a displacement reaction zone, a three-phase separation zone, and an effluent zone connected in sequence, with the effluent zone surrounding the upper part of the three-phase separation zone. The water distribution and gas distribution zone is provided with a reactor inlet 2 and a reactor gas inlet 4, which are respectively connected to a water distribution pipe 3 and a gas distribution pipe 5 to achieve uniform water and gas distribution; a support distribution plate 6 is also provided between the water distribution pipe 3 and the gas distribution pipe 5, and a discharge inspection port 23 is provided above the gas distribution pipe 5 in the water distribution and gas distribution zone. The displacement reaction zone, from bottom to top, includes a support layer 7 and an aluminum particle layer 8. An aluminum particle feed port 9 is located above the aluminum particle layer 8 in the displacement reaction zone for adding aluminum particles into the reactor. The diameter of the three-phase separation zone is larger than that of the displacement reaction zone. The three-phase separation zone is equipped with a three-phase separator 10, which consists of a central tube and a bell-shaped cover. The flared end of the cover faces downwards, and one end of the central tube connects to the constricted end of the cover, while the other end extends out of the device to achieve water, gas, and solid three-phase separation and prevent aluminum particle loss. The cover consists of an upper cover, a lower cover, and connecting parts. The connecting parts support the overlapping portions of the upper and lower covers to form a flow channel (i.e., a water phase outlet). The flow passage of the three-phase separator 10 is connected to the outlet area, and a water collection tank 11 is provided around the top of the outlet area. The outlet area is provided with an outlet 12 that is connected to the sedimentation tank inlet 14 of the sedimentation tank 13. The sedimentation tank 13 is also provided with a sedimentation tank outlet 15, a circulating water outlet 16, and a sedimentation outlet 18. The sedimentation tank outlet 15, the circulating water outlet 16, and the sedimentation outlet 18 are respectively located at the top, middle, and bottom of the sedimentation tank 13, and a filter screen 17 is also provided on the circulating water outlet 16.

[0046] See also Figure 1 The apparatus for recovering copper from waste ionic liquid of the present invention further includes a feed pump 20, a circulation pump 21 and an air pump 22. Circulating water enters the circulation pump 21 through the circulating water outlet 16. The oil removal digestion solution is simultaneously input into the reactor inlet 2 by the feed pump 20 and the circulating water through the circulation pump 21. The carrier gas is input into the reactor inlet 4 by the air pump 22.

[0047] In some preferred embodiments, the apparatus for recovering copper from waste ionic liquid of the present invention further includes a digestion reactor and an oil removal device connected in series. The digestion reactor is used to receive the waste ionic liquid and digest it, and the oil removal device is used to receive the digested material and remove oil from it. The outlet of the oil removal device is connected to the inlet of the reactor. Preferably, the digestion reactor is a fully mixed reactor, and the oil removal device is selected from at least one of an oil separator, an oil removal settling tank, and an oil separator. The feed pump 20 is located between the oil removal device and the reactor inlet 2, and the circulation pump 21 is located between the circulating water outlet 16 and the reactor inlet 2.

[0048] The treatment process of the deoiled digestate obtained from the pretreatment of the waste ionic liquid in the above-mentioned device is as follows:

[0049] After pretreatment, the de-oiled digestate obtained from the waste ionic liquid enters the feed tank 19 for storage. The feed tank 19 is connected to the feed pump 20, thus the de-oiled digestate enters the feed pump 20. At the same time, part of the supernatant in the sedimentation tank 13 is filtered through the filter screen 17 and enters the circulating water outlet 16 into the circulating pump 21. The mixture obtained by mixing the effluent from the feed pump 20 and the effluent from the circulating pump 21 enters the expanded bed replacement reactor 1 through the reactor inlet 2 at the bottom of the expanded bed replacement reactor 1. The water flow is first distributed through the water distribution pipe 3, and then distributed through the support distribution plate 6. At the same time, the air pump 22 blows air or nitrogen into the expanded bed replacement reactor 1 through the reactor air inlet 4. After being distributed through the air distribution pipe 5, the air or nitrogen mixes with the above-mentioned mixture that has been distributed through the support distribution plate 6 to form a gas-containing mixture. The gas-containing mixture enters the replacement reaction zone and passes through the support... After layer 7, the mixture enters aluminum particle layer 8. Here, copper ions in the gas-containing mixture undergo a displacement reaction with the aluminum particles to generate elemental copper. Under the action of the upward flowing water / air, the aluminum particles in aluminum particle layer 8 are in an expanded state. Furthermore, under the disturbance of the water / air, the elemental copper generated by the displacement reaction exists in the form of flocs, i.e., copper flocs. The gas-containing mixture, after passing through aluminum particle layer 8, forms a mixture containing copper flocs. It continues to flow upward to the three-phase separation zone. After the separation action of the three-phase separator 10, the air is discharged from the central tube of the three-phase separator 10, and the aluminum particles carried up by the water / air fall back into the displacement reaction zone. The mixture containing copper flocs enters the effluent zone from the aqueous phase outlet. In the effluent zone, the mixture containing copper flocs enters the water collection tank 11 and flows out of the expanded bed displacement reactor 1 from the reactor outlet 12. It then enters the sedimentation tank 13 through the sedimentation tank inlet 14.

[0050] In the settling tank 13, the copper flocs in the mixed liquid containing copper flocs settle to the bottom of the settling tank, forming copper precipitate, which can be collected from the settling outlet 18 at regular intervals. Part of the supernatant is discharged from the settling tank outlet 15 for further processing, and part of the supernatant is filtered through the filter screen 17 and enters the circulating pump 21 from the circulating water outlet 16 to complete the circulation process of the supernatant. During the above process, aluminum particles can be added into the expanded bed replacement reactor 1 through the aluminum particle feeding port 9, and the material can also be discharged from the reactor through the unloading inspection port 23.

[0051] The interior of the expanded bed replacement reactor 1 can be inspected periodically or when a malfunction occurs through the unloading inspection port 23.

[0052] Example 1

[0053] Waste ionic liquid from the alkylation of oil products at a petrochemical plant (mainly containing 26.8 wt% triethylamine hydrochloride, 39.5 wt% aluminum chloride, 29.7 wt% copper chloride, and 4 wt% acid-soluble oil) was digested with 25 wt% concentrated brine at a feed volume ratio of 1:50. The pH of the acidic digestate after the digestion reaction stabilized at 2.85. The resulting acidic digestate was then sequentially fed into an oil removal settling tank and a ceramic membrane oil separator for further oil removal. The residence time in the settling tank was 7 hours, and the pore size of the ceramic membrane oil separator was 0.05 μm. The resulting oil-removed digestate had an oil content of 2 mg / L and a copper concentration of 1880 mg / L.

[0054] The degreasing and digestion solution enters expanded bed displacement reactor 1, with a height-to-diameter ratio of 7:1. In this reactor, metallic copper is displaced by aluminum particles with a particle size of 2 mm. The aluminum particle packing volume ratio in the reaction zone is 30%. The upflow velocity in expanded bed displacement reactor 1 is 120 m / h. Nitrogen gas is introduced from the bottom of the reactor to enhance the removal of copper flocs, with a gas flow rate of 80 L / m³. 2 / s; feed residence time 30min, sedimentation residence time 45min; metallic copper was obtained from the sedimentation tank, and the copper purity was measured to be 99.5%, with a copper concentration of 8mg / L in the sedimentation tank effluent.

[0055] Example 2

[0056] Waste ionic liquid from the alkylation of oil products at a petrochemical plant (mainly containing 27.5 wt% triethylamine hydrochloride, 40.3 wt% aluminum chloride, 28.7 wt% copper chloride, and 3.5 wt% acid-soluble oil) was digested with 15 wt% concentrated brine at a feed volume ratio of 1:60. The pH of the acidic digestate after the digestion reaction stabilized at 2.97. The resulting acidic digestate was then subjected to oil removal treatment in an oil settling tank and a ceramic membrane oil separator. The residence time in the settling tank was 6.5 h, and the pore size of the ceramic membrane oil separator was 0.1 μm. The resulting oil-removed digestate had an oil content of 1 mg / L and a copper concentration of 1060 mg / L.

[0057] The degreasing and digestion solution enters expanded bed displacement reactor 1, with a height-to-diameter ratio of 6:1. In this reactor, metallic copper is displaced by aluminum particles with a particle size of 0.5 mm. The aluminum particle packing volume ratio in the reaction zone is 70%. The upflow velocity in expanded bed displacement reactor 1 is 30 m / h. The removal of copper flocs is enhanced by venting air from the bottom of the reactor at an air flow rate of 15 L / m². 2 / s; feed residence time 40min, sedimentation residence time 35min; metallic copper was obtained from the copper recovery reactor, and the copper purity was measured to be 99.2%, with an effluent copper concentration of 7.6mg / L.

[0058] Any numerical value mentioned in this invention, if there is only a two-unit interval between any minimum and any maximum value, includes all values ​​that increase by one unit each time from the minimum to the maximum value. For example, if the amount of a component, or the value of a process variable such as temperature, pressure, or time, is stated as 50-90, in this specification it means specifically listing values ​​such as 51-89, 52-88… and 69-71 and 70-71, etc. For non-integer values, it may be appropriately considered that a unit is 0.1, 0.01, 0.001, or 0.0001. These are merely some specifically specified examples. In this application, in a similar manner, all possible combinations of numerical values ​​between the listed minimum and maximum values ​​are considered to have been disclosed.

[0059] It should be noted that the embodiments described above are only for explaining the present invention and do not constitute any limitation on the present invention. The present invention has been described with reference to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory terms, not limiting terms. Modifications can be made to the present invention within the scope of the claims, and revisions can be made to the present invention without departing from the scope and spirit of the present invention. Although the present invention described herein relates to specific methods, materials, and embodiments, it does not mean that the present invention is limited to the specific examples disclosed herein; on the contrary, the present invention can be extended to all other methods and applications with the same function.

Claims

1. A method for recovering copper from waste ionic liquid, using an apparatus for recovering copper from waste ionic liquid, characterized in that, The apparatus for recovering copper from waste ionic liquid includes: a displacement reactor and a sedimentation tank. The displacement reactor comprises, from bottom to top, a water distribution and gas distribution zone, a displacement reaction zone, a three-phase separation zone, and an effluent zone, which are connected in sequence. The effluent zone surrounds the upper part of the three-phase separation zone. The water distribution and gas distribution zone is provided with a reactor inlet and a reactor gas inlet. The displacement reaction zone comprises, from bottom to top, a support layer and an aluminum particle layer. The three-phase separation zone is provided with a three-phase separator, and the aqueous phase outlet of the three-phase separator is connected to the effluent zone. The effluent zone is connected to the sedimentation tank. The sedimentation tank is provided with a sedimentation tank outlet, a circulating water outlet, and a sedimentation collection outlet at its upper, middle, and bottom parts, respectively. The method for recovering copper from waste ionic liquid includes the following steps: Step 1, Pretreatment, includes: digesting the waste ionic liquid to eliminate its activity, and then performing degreasing treatment to obtain a degreased digestion solution; Step 2, gas-liquid mixing, includes: the oil removal and digestion solution is mixed with circulating water and enters the water and gas distribution zone, and mixes with the gas in the water and gas distribution zone to form a gas-containing mixture; Step 3, replacement, includes: the gas-containing mixture enters the replacement reaction zone, where copper ions react with aluminum particles in the aluminum particle layer to generate elemental copper. Under the action of upward flowing water / air, elemental copper is generated as copper flocs, and the gas-containing mixture becomes a mixture containing copper flocs. The aluminum particles are in an expanded state, and some of the aluminum particles enter the three-phase separation zone with the mixture containing copper flocs. Step 4, three-phase separation, includes: separation in the three-phase separation zone, gas discharge device in the copper-containing flocculent mixture, aluminum particles falling back into the displacement reaction zone, and the copper-containing flocculent mixture entering the sedimentation tank via the effluent zone; Step 5, sedimentation, includes: the mixed liquid containing copper flocs settles in the sedimentation tank to obtain bottom copper precipitate and supernatant. The copper precipitate is collected from the sedimentation outlet, and part of the supernatant is used as circulating water and part is discharged from the device.

2. The method according to claim 1, characterized in that, The displacement reactor is an expanded bed displacement reactor; and / or the water and gas distribution zone includes interconnected water distribution zone and gas distribution zone from bottom to top, and / or the water and gas distribution zone is also provided with a reactor unloading and maintenance port.

3. The method according to claim 2, characterized in that, The water distribution area is provided with a water distribution pipe and a supporting distribution plate, and / or the air distribution area is provided with an air distribution pipe; and / or the unloading inspection port is located above the air distribution pipe.

4. The method according to claim 3, characterized in that, The support distribution plate is provided with uniformly arranged strip holes, and the diameter of the strip holes is smaller than the pore diameter of the support layer.

5. The method according to any one of claims 1-4, characterized in that, The three-phase separator includes a central tube and a funnel-shaped cover with the flared end of the cover facing downwards. One end of the central tube is connected to the constricted end of the cover, and the other end extends out of the device. The water phase outlet is located on the cover. And / or a water collection tank is provided at the top of the water outlet area, and the water collection tank is provided with a reactor outlet connected to the sedimentation tank. And / or a circulating water outlet is provided in the middle of the sedimentation tank.

6. The method according to claim 5, characterized in that, The cover is composed of an upper cover, a lower cover, and a connector. The connector supports the overlapping parts of the upper cover and the lower cover to form a flow channel, i.e., a water phase outlet; and / or a filter screen is provided on the circulating water outlet.

7. The method according to any one of claims 1-4, characterized in that, The height-to-diameter ratio of the displacement reactor is 5:1-8:1; and / or the particle size of the aluminum particles in the aluminum particle layer is 0.5-2 mm; and / or the volume ratio of the aluminum particles in the displacement reaction zone is 20-80%; and / or the displacement reaction zone is provided with an aluminum particle feeding port above the aluminum particle layer.

8. The method according to any one of claims 1-4, characterized in that, The apparatus further includes a digestion reactor and an oil removal device connected in series. The digestion reactor is used to receive waste ionic liquid and digest it. The oil removal device is used to receive the digested material and remove oil from it. The outlet of the oil removal device is connected to the inlet of the reactor. And / or the apparatus further includes a feed pump, a circulation pump, and an air pump. The feed pump is located between the oil removal device and the inlet of the reactor. The circulation pump is located between the circulating water outlet and the inlet of the reactor. The air pump is connected to the air inlet of the reactor.

9. The method according to claim 8, characterized in that, The digestion reactor is a fully mixed reactor, and / or the oil removal equipment is selected from at least one of an oil separator, an oil removal settling tank, and an oil separator.

10. The method according to claim 9, characterized in that, The oil separator is an inclined plate oil separator, and / or the oil remover is a ceramic membrane oil remover.

11. The method according to claim 10, characterized in that, The ceramic membrane in the ceramic membrane oil separator has a pore size of 0.05-0.2 μm.

12. The method according to any one of claims 1-4, characterized in that, The waste ionic liquid is a waste ionic liquid from the alkylation of oil products.

13. The method according to claim 12, characterized in that, The waste ionic liquid is generated from the production of alkylated oil from C4 by catalyzing aluminochloride-based ionic liquids.

14. The method according to claim 13, characterized in that, The waste ionic liquid includes transition metal salt compounds.

15. The method according to any one of claims 1-4, characterized in that, The digestion in step 1 uses concentrated saline solution with a sodium chloride concentration of 15-25 wt%, and / or the pH of the digestion solution obtained is 2.5-4.

16. The method according to claim 15, characterized in that, The feed volume ratio of the waste ionic liquid to the concentrated brine is 1:(45-60).

17. The method according to any one of claims 1-4, characterized in that, In step 2, the copper concentration in the degreasing and digestion solution is 1000-2000 mg / L, and the oil content is less than 5 mg / L; and / or the gas flow rate into the water and gas distribution zone is 10-90 L / m². 2 / s; and / or the gas is selected from nitrogen or air.

18. The method according to any one of claims 1-4, characterized in that, The upflow velocity in the displacement reactor is 30-120 m / h, and the feed residence time is 20-40 min; and / or the residence time of the copper-containing flocculent mixture in the sedimentation tank is not less than 30 min, and the copper concentration in the supernatant is less than 15 mg / L.

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