Device and method for recovering extractant from raffinate

Abstract

The present invention belongs to the field of extractant recovery, and relates to an apparatus and method for recovering extractant from raffinate. The method comprises: adjusting the pH value of the raffinate to 1.5-5, and then standing to clarify and separate, the extractant in the obtained clarified raffinate is captured and recovered by using a capture agent for more than 2 levels, after each level of capture and recovery is completed, the obtained capture agent containing the extractant is circulated as the capture agent of that level, and the obtained raffinate enters the next level of capture and recovery, and the raffinate obtained after the last level of capture and recovery is completed is standing to clarify and separate, the obtained oil phase is returned to the last level of capture and recovery, and the obtained water phase is discharged; when the concentration of the extractant contained in the first level capture agent reaches the set value, it is drawn out, and the capture agent of each subsequent level is used as the capture agent of the previous level, and a fresh extraction system pure diluent is added as a capture agent in the last level, and capture and recovery is continued. The method can effectively capture and recover the extractant, reduce the loss of the extractant, and reduce the impact on the next process.

Description

Technical Field

[0001] The invention belongs to the field of extractant recovery, and in particular relates to a device and a method for recovering an extractant from a raffinate. Background Art

[0002] The separation and purification of metal ions (such as Co, Ni, Mn, Cu, Fe, Ca, W, etc.) by extraction has been widely used. The raffinate obtained after extraction still contains some extractant. At present, the method for recovering the extractant from the raffinate is usually to increase the clarification stage and let it stand, recover the organic phase floating on the surface (the organic phase is the extractant), and the clarified raffinate is directly discharged to the next process. However, the clarified raffinate obtained by this method still contains valuable extractants that are not recovered, and there is a problem of extractant loss. Moreover, after long-term operation, the extractant dissolved in the clarified raffinate may have an adverse effect on the control of the next process. Therefore, it is very necessary to develop a device and method that can further recover the extractant in the clarified raffinate. Summary of the invention

[0003] The purpose of the present invention is to overcome the problem that when the raffinate is treated by the existing device and method, there is a loss of extractant and an adverse effect on the control of the next process, and to provide an apparatus and method that can effectively capture and recover the extractant in the raffinate.

[0004] Specifically, the present invention provides a device for recovering an extractant from a raffinate, wherein the device comprises a pH value adjusting device and an extractant recovery device; the extractant recovery device comprises a first-stage extractant clarifier, an n-stage extractant recovery device and a final-stage extractant clarifier, n≥2, the material outlet of the pH value adjusting device is connected to the material inlet of the first-stage extractant clarifier, the water phase outlet of the first-stage extractant clarifier is connected to the material inlet of the first-stage extractant recovery device, and the oil phase outlet of the first-stage extractant clarifier is connected to the extraction system; each stage of the extractant recovery device in the n-stage extractant recovery device is provided with a capture agent circulation loop, the raffinate outlet of each stage of the extractant recovery device is connected to the material inlet of the next stage of the extractant recovery device, and the capture agent outlet of each stage of the extractant recovery device is connected to the material inlet of the previous stage of the extractant recovery device; the raffinate outlet of the final stage of the extractant recovery device is connected to the material inlet of the final stage of the extractant clarifier, and the oil phase outlet of the final stage of the extractant clarifier is connected to the material inlet of the final stage of the extractant recovery device.

[0005] Furthermore, each extractant recoverer in the n-stage extractant recoverers independently has the first structure or the second structure: the first structure: the extractant recoverer includes a mixing chamber, a static separation chamber and a capture agent circulation tank, the outlet of the mixing chamber is connected to the inlet of the static separation chamber, and the static separation chamber, the capture agent circulation tank and the mixing chamber are connected in sequence under the action of a circulation pump to form a capture agent circulation loop; the second structure: the extractant recoverer includes a mixing chamber, a static separation chamber and a capture agent reflux dark channel, the outlet of the mixing chamber is connected to the inlet of the static separation chamber, and the outlet of the static separation chamber is connected to the inlet of the mixing chamber through the capture agent reflux dark channel under the action of a reflux regulating pipe to form a capture agent circulation loop.

[0006] Furthermore, a stirrer is provided in the mixing chamber.

[0007] The present invention also provides a method for recovering an extractant from a raffinate, the method comprising the following steps:

[0008] (1) Extraction agent clarification and recovery:

[0009] The pH value of the raffinate to be recovered is adjusted to 1.5 to 5, and then allowed to stand for clarification and separation to obtain floating oil and clarified raffinate;

[0010] (2) Extractant recycling capture and recovery:

[0011] S1, the extractant in the clarified raffinate is captured and recovered by using a capture agent for more than 2 levels, after each level of capture and recovery is completed, the obtained capture agent containing the extractant is recycled as the capture agent of this level, and the obtained raffinate enters the next level of capture and recovery, the raffinate obtained after the last level of capture and recovery is statically clarified and separated, the obtained oil phase is returned to the last level of capture and recovery of the extractant, and the obtained water phase is discharged;

[0012] S2. When the concentration of the extractant contained in the first-stage capture agent reaches the set value, it is drawn out, and the capture agent of each subsequent stage is used as the capture agent of the previous stage. In the last stage, fresh pure diluent of the extraction system is added as the capture agent, and then the method of step S1 is used to capture and recover the extractant.

[0013] Furthermore, the set value refers to that the concentration of the extractant reaches 0.2 to 2.0 times the concentration of the extractant in the extraction system.

[0014] Furthermore, the first-stage capture agent after the floating oil and the extractant concentration reach the set value is returned to the extraction system for extraction.

[0015] Furthermore, the method for recovering the extractant from the raffinate provided by the present invention adopts n-stage extractant recovery, where n≥2, and the specific steps include:

[0016] (1) Extraction agent clarification and recovery:

[0017] The pH value of the raffinate to be recovered is adjusted to 1.5 to 5, and then allowed to stand for clarification and separation to obtain floating oil and clarified raffinate, wherein the floating oil is returned to the extraction system for extraction;

[0018] (2) Extractant recycling capture and recovery:

[0019] S1, the clarified raffinate enters the first extractant recovery stage and is mixed with the first-stage capture agent, and then is allowed to stand for clarification and separation, to obtain a first-stage extractant-containing capture agent and a first-stage raffinate; the first-stage extractant-containing capture agent is circulated as the first-stage capture agent and is continuously mixed with the fresh clarified raffinate, and then is allowed to stand for clarification and separation, the first-stage raffinate enters the second extractant recovery stage and is mixed with the second-stage capture agent, and then is allowed to stand for clarification and separation, to obtain a second-stage extractant-containing capture agent and a second-stage raffinate; the second-stage extractant-containing capture agent is circulated as the second-stage capture agent and is continuously mixed with the fresh first-stage raffinate, and then is allowed to stand for clarification and separation, the second-stage raffinate enters the next extractant recovery stage for extractant capture and recovery; and so on. After the n-1th stage extractant capture and recovery, an n-1th stage extractant-containing capture agent and an n-1th stage raffinate are obtained; the n-1th stage extractant-containing capture agent is circulated as an n-1th stage capture agent and is continuously mixed with a fresh n-2th stage raffinate before being allowed to stand for clarification and separation; the n-1th stage raffinate enters the nth extractant recovery stage and is mixed with the nth stage capture agent before being allowed to stand for clarification and separation, thereby obtaining an nth stage extractant-containing capture agent and an nth stage raffinate; the nth stage extractant-containing capture agent is circulated as an nth stage capture agent and is continuously mixed with a fresh n-1th stage raffinate before being allowed to stand for clarification and separation; the nth stage raffinate is allowed to stand for clarification and separation, the obtained oil phase is returned to the nth extractant recovery stage, and the obtained water phase is discharged;

[0020] S2. When the concentration of the extractant in the first-stage extractant-containing capture agent reaches 0.2 to 2.0 times the extractant concentration in the extraction system, it is returned to the extraction system for extraction, and the capture agent of each subsequent stage is used as the capture agent of the previous stage. A new extraction system pure diluent is added as the capture agent at the nth extractant recovery stage, and then the extractant is captured and recovered using the method of step S1.

[0021] Furthermore, when the first-stage extractant-containing capture agent after the floating oil and extractant concentrations reach the set values ​​is returned to the extraction system for extraction, when the extractant concentration contained therein is lower than the required value of the extractant in the extraction system, additional extractant needs to be added to increase the concentration to the required value; when the extractant concentration contained therein is higher than the required value of the extractant in the extraction system, additional diluent needs to be added to reduce the concentration to the required value.

[0022] Furthermore, the pH value of the raffinate to be recovered is adjusted to 1.5-5 using an acid as the pH adjuster, and the adjustment is performed in any of the following ways: ① the raffinate to be recovered and the acid are added to a stirring tank respectively for stirring; ② the acid and the raffinate are continuously added by a venturi tube for mixing; ③ the acid is directly added to the mixing chamber of the extraction system for stirring and mixing with the raffinate to be recovered.

[0023] Furthermore, the method for recovering the extractant from the raffinate provided by the present invention is carried out in the above-mentioned device for recovering the extractant from the raffinate.

[0024] The device and method for recovering the extractant from the raffinate provided by the present invention can effectively capture and recover the extractant dissolved in the raffinate, reduce the loss of the extractant, and reduce the impact on the next process. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 A specific structural diagram of the extractant recovery device provided by the present invention;

[0026] Figure 2 Another specific structural diagram of the extractant recoverer provided by the present invention. DETAILED DESCRIPTION

[0027] The device for recovering an extractant from a raffinate provided by the present invention comprises a pH value regulating device and an extractant recovery device; the extractant recovery device comprises a first-stage extractant clarifier, an n-stage extractant recovery device and a final-stage extractant clarifier (n≥2, preferably 2-4), a material outlet of the pH value regulating device is communicated with a material inlet of the first-stage extractant clarifier, a water phase outlet of the first-stage extractant clarifier is communicated with a material inlet of a first-stage extractant recovery device, and an oil phase outlet of the first-stage extractant clarifier is communicated with an extraction system; each stage of the n-stage extractant recovery devices is provided with a capture agent circulation loop, a raffinate outlet of each stage of the extractant recovery device is communicated with a material inlet of a next-stage extractant recovery device, and a capture agent outlet of each stage of the extractant recovery device is communicated with a material inlet of an upper-stage extractant recovery device; a raffinate outlet of the final-stage extractant recovery device is communicated with a material inlet of a final-stage extractant clarifier, and an oil phase outlet of the final-stage extractant clarifier is communicated with a material inlet of the final-stage extractant recovery device. Among them, a switch is provided on the pipeline connecting the capture agent outlet of each stage of the extractant recovery device with the material inlet of the extractant recovery device of the previous stage. The switch is closed when the extractant is circulating in the current stage, and is opened when the extractant needs to be replaced step by step. After the replacement is completed, the switch is closed again to continue the circulation of the current stage.

[0028] When working, the raffinate to be recovered is introduced into the pH value adjusting device for pH value adjustment, and then introduced into the first-stage extractant clarifier for static clarification and separation to obtain floating oil and clarified raffinate. The floating oil is discharged or returned to the extraction system for extraction, and the clarified raffinate enters the extractant recovery device to use the capture agent to capture and recover the extractant at more than 2 levels. After each level of capture is completed, the obtained capture agent containing the extractant is recycled as the capture agent of this level, and the obtained raffinate enters the next level of capture and recovery. The last level of raffinate is introduced into the final-stage extractant clarifier for static clarification and separation to obtain an oil phase and a water phase. The oil phase returns to the last level of capture and recovery of the extractant, and the water phase is discharged to the next process. When the concentration of the extractant contained in the first-stage capture agent reaches the set value, it is drawn out, and the capture agent of each subsequent level is used as the capture agent of the previous level. Fresh pure diluent of the extraction system is added as the capture agent in the last level, and then the capture agent is used to capture and recover at more than 2 levels by the above method, and this cycle is used to achieve full recovery of the extractant. In addition, when the equipment starts to run, pure diluent of the extraction system can be added to each stage as a capture agent. After the operation is stable, the capture agent of each stage is replaced step by step as a capture agent, and only fresh pure diluent of the extraction system needs to be added to the last stage.

[0029] According to a specific embodiment of the present invention, Figure 1 As shown, the extractant recovery device includes a mixing chamber 11, a static separation chamber 12 and a capture agent circulation tank 13, the outlet of the mixing chamber 11 is connected to the inlet of the static separation chamber 12, and the static separation chamber 12, the capture agent circulation tank 13 and the mixing chamber 11 are sequentially connected under the action of a circulation pump 14 to form a capture agent circulation loop. Among them, the mixing chamber 11 is used to mix the raffinate and the capture agent evenly. The mixing chamber 11 is usually provided with a stirrer to facilitate the mixing of materials. The static separation chamber 12 is used to statically clarify and separate the mixed liquid from the mixing chamber 11. After static separation, the upper layer is a capture agent rich in extractant, and the lower layer is a raffinate poor in extractant. The capture agent circulation tank 13 is used to cache the circulating capture agent. After circulation, the extractant contained in the capture agent is continuously enriched and replaced and captured step by step. When the extractant concentration in the capture agent used in the first-stage extractant recovery device reaches the set value, it is returned to the extraction system. The capture agent of each subsequent stage is used as the capture agent of the previous stage, and a fresh extraction system pure diluent is added as the capture agent in the last stage. At this time, the material inlet of the extraction recovery device is set at the mixing chamber 11, the oil phase outlet is set at the upper part of the static separation chamber 12 (the position of the capture agent), and the raffinate outlet is set at the lower part of the static separation chamber 12 (the position of the raffinate).

[0030] According to another specific embodiment of the present invention, Figure 2As shown, the extractant recovery device includes a mixing chamber 21, a static separation chamber 22 and a capture agent reflux dark channel 23, the outlet of the mixing chamber 21 is connected to the inlet of the static separation chamber 22, and the outlet of the static separation chamber 22 is connected to the inlet of the mixing chamber 21 through the capture agent reflux dark channel 23 under the action of the reflux regulating pipe 24 to form a capture agent circulation loop. Among them, the mixing chamber 21 is used to mix the raffinate and the capture agent evenly. The mixing chamber 21 is usually provided with a stirrer to facilitate the mixing of materials. The static separation chamber 22 is used to statically clarify and separate the mixed liquid from the mixing chamber 21. After static separation, the upper layer is the capture agent rich in extractant, and the lower layer is the raffinate poor in extractant. The capture agent reflux dark channel 23 is usually arranged at the bottom of the mixing chamber 21 and the static separation chamber 22, and is used to recycle the capture agent. After the cycle, the extractant contained in the capture agent is continuously enriched and replaced step by step. When the extractant concentration in the capture agent used by the first-stage extractant recovery device reaches the set value, it is returned to the extraction system. The capture agent of each subsequent stage is used as the capture agent of the previous stage, and the last stage adds fresh extraction system pure diluent as the capture agent. At this time, the material inlet of the extraction recovery device is set in the mixing chamber 21, the oil phase outlet is set in the upper part of the static separation chamber 22 (the position of the capture agent), and the raffinate outlet is set in the lower part of the static separation chamber 22 (the position of the raffinate).

[0031] In the present invention, the pH value adjusting device may be a stirring tank. The feeding method of the stirring tank may be dripping, one-time addition or continuous feeding through a venturi tube. The stirring tank may be an independently arranged stirring tank or a mixing chamber of an extraction system. Accordingly, the pH value may be adjusted in the following manners: ① adding the raffinate to be recovered and the acid to the stirring tank respectively for stirring; ② using a venturi tube feeding method to continuously feed the acid and the raffinate for mixing; ③ adding the acid directly to the mixing chamber of the extraction system for stirring and mixing with the raffinate to be recovered.

[0032] In the present invention, the terms "first stage" and "final stage" are introduced only for the convenience of description to distinguish the extractant clarifiers at different positions. The first stage extractant clarifier and the final stage extractant clarifier can be various existing devices capable of separating the oil phase and the water phase in the raffinate to be recovered, and can be a static tank.

[0033] The method for recovering an extractant from a raffinate provided by the present invention comprises the following steps:

[0034] (1) Extraction agent clarification and recovery:

[0035] The pH value of the raffinate to be recovered is adjusted to 1.5-5, and then allowed to stand for clarification and separation to obtain floating oil and clarified raffinate. The floating oil is the extractant, which is preferably returned to the extraction system for extraction. The pH value adjuster used to adjust the pH value of the raffinate to be recovered to 1.5-5 is an acid, including an organic acid and an inorganic acid. Specific examples of the organic acid include, but are not limited to, oxalic acid, citric acid, acetic acid, succinic acid, etc. Specific examples of the inorganic acid include, but are not limited to, sulfuric acid, phosphoric acid, nitric acid, hydrochloric acid, etc. The acid H + The ion concentration can be controlled at 0.1-10 mol / L. The specific pH adjustment method can be carried out in the following ways: ① Add the raffinate to be recovered and the acid into the stirring tank respectively for stirring; ② Use the venturi tube feeding method to continuously add the acid and the raffinate for mixing; ③ Add the acid directly into the mixing chamber of the extraction system and stir and mix with the raffinate to be recovered.

[0036] (2) Extractant recycling capture and recovery:

[0037] S1. The extractant in the clarified raffinate is captured and recovered in two or more stages by using a capture agent. After each stage of capture and recovery is completed, the obtained capture agent containing the extractant is recycled as the capture agent of that stage, and the obtained raffinate enters the next stage of capture and recovery. After the last stage of capture and recovery is completed, the obtained raffinate is statically clarified and separated, the obtained oil phase is returned to the last stage of capture and recovery, and the obtained water phase is discharged. Specifically, assuming that n-stage extractant recovery (n≥2) is adopted, the clarified raffinate enters the first extractant recovery stage and is mixed with the first-stage capture agent, and then is allowed to stand for clarification and separation, to obtain the first-stage extractant-containing capture agent and the first-stage raffinate; the first-stage extractant-containing capture agent is circulated as the first-stage capture agent and is continuously mixed with the fresh clarified raffinate, and then is allowed to stand for clarification and separation, and the first-stage raffinate enters the second extractant recovery stage and is mixed with the second-stage capture agent, and then is allowed to stand for clarification and separation, to obtain the second-stage extractant-containing capture agent and the second-stage raffinate; the second-stage extractant-containing capture agent is circulated as the second-stage capture agent and is continuously mixed with the fresh first-stage raffinate, and then is allowed to stand for clarification and separation, and the second-stage raffinate enters the next extractant recovery stage for extraction The extractant is captured and recovered at the n-1th stage; and by analogy, after the n-1th stage extractant is captured and recovered, an n-1th stage extractant-containing capture agent and an n-1th stage raffinate are obtained, the n-1th stage extractant-containing capture agent is circulated as the n-1th stage capture agent and is continuously mixed with the fresh n-2th stage raffinate, and then is allowed to stand for clarification and separation, the n-1th stage raffinate enters the nth extractant recovery stage and is mixed with the nth stage capture agent, and then is allowed to stand for clarification and separation, to obtain an nth stage extractant-containing capture agent and an nth stage raffinate; the nth stage extractant-containing capture agent is circulated as the nth stage capture agent and is continuously mixed with the fresh n-1th stage raffinate, and then is allowed to stand for clarification and separation, the nth stage raffinate is allowed to stand for clarification and separation, the obtained oil phase is returned to the nth extractant recovery stage, and the obtained water phase is discharged.

[0038] S2. When the concentration of the extractant contained in the first-stage capture agent reaches the set value (usually 0.2 to 2.0 times the extractant concentration in the extraction system), it is drawn out (preferably returned to the extraction system for extraction), and the capture agent of each subsequent stage is used as the capture agent of the previous stage. In the last stage, fresh pure diluent of the extraction system is added as the capture agent, and then the method of step S1 is used to capture and recover the extractant.

[0039] In the present invention, the oil slick is the extractant, and the first-stage capture agent is rich in the extractant. Therefore, it is preferred to return the oil slick and / or the first-stage capture agent to the extraction system for extraction to achieve full utilization of resources. When the oil slick and the first-stage capture agent are returned to the extraction system for extraction, it should be determined whether to add the extractant or diluent according to the concentration of the extractant therein. For example, when the concentration of the extractant contained in the oil slick and the first-stage capture agent is lower than the required value of the extractant in the extraction system, additional extractant needs to be added to increase the concentration to the required value; when the concentration of the extractant contained in the oil slick and the first-stage capture agent is higher than the required value, additional diluent needs to be added to reduce the concentration to the required value.

[0040] In the present invention, the raffinate to be recovered can be, for example, the raffinate obtained by extracting and recovering metal elements such as Co, Ni, Mn, Cu, Fe, Ca, and W from raw materials such as cobalt intermediates, nickel intermediates, cobalt-copper alloys, tungsten-cobalt alloys, crude cobalt-nickel sulfate solutions, and crude manganese sulfate solutions. Among them, the extractant used is usually selected from at least one of an acidic phosphorus extractant (such as a P204 extractant, a P507 extractant, a C272 extractant, etc.), a neutral phosphorus extractant (such as a TBP extractant, a P350 extractant, etc.), an organic carboxylic acid (such as cyclohexane acid, a tertiary carbon carboxylic acid, etc.), an aldoxime extractant (such as a LIX63 extractant, a LIX64 extractant, a LIX984 extractant, etc.), and an amine extractant (such as an N235 extractant, an N263 extractant, etc.). The diluent used is usually selected from at least one of sulfonated kerosene, 260# solvent oil, 260 sulfonated kerosene, Escaid 110, Escaid 115, Isopae E and the like.

[0041] In the present invention, the pure diluent in the extraction system is the same as the diluent in the raffinate to be recovered.

[0042] The present invention will be described in detail below through examples.

[0043] Example 1

[0044] This embodiment adopts a three-stage cycle to capture the extractant (i.e., n=3), wherein the extractant recovery device used in each stage has Figure 1The structure shown includes a mixing chamber 11, a static separation chamber 12 and a capture agent circulation groove 13. The outlet of the mixing chamber 11 is connected to the inlet of the static separation chamber 12. The static separation chamber 12, the capture agent circulation groove 13 and the mixing chamber 11 are connected in sequence under the action of a circulation pump 14 to form a capture agent circulation loop.

[0045] (1) Extraction agent clarification and recovery:

[0046] The pH value of the raffinate to be recovered (containing 260# solvent oil as diluent, P507 extractant as extractant, and the concentration of the extractant as 0.75 mol / l) was measured by H + The concentration of 5 mol / L hydrochloric acid is adjusted to 2, and then allowed to stand for clarification and separation to obtain floating oil and clarified raffinate, and the floating oil is returned to the extraction system for extraction;

[0047] (2) Extractant recycling capture and recovery:

[0048] S1, the clarified raffinate enters the first extractant recovery stage, and adopts Figure 1 The circulated capture agent in the manner shown is mixed and then allowed to stand for clarification and separation to obtain a first-stage capture agent containing an extractant and a first-stage raffinate; the first-stage capture agent containing an extractant is circulated as a first-stage capture agent and is further mixed with the fresh clarified raffinate and then allowed to stand for clarification and separation, and the first-stage raffinate enters the second extractant recovery stage and is then mixed with the first-stage raffinate using Figure 1 The captured agent circulated in the manner shown in the figure is mixed and then allowed to stand for clarification and separation to obtain a second-stage captured agent containing an extractant and a second-stage raffinate; the second-stage captured agent containing an extractant is circulated as a second-stage captured agent and is continuously mixed with the fresh first-stage raffinate and then allowed to stand for clarification and separation, and the second-stage raffinate enters the third extractant recovery stage and is then mixed with the first-stage raffinate using the method of Figure 1 After the circulated capture agent is mixed, it is allowed to stand for clarification and separation to obtain a third-stage capture agent containing an extractant and a third-stage raffinate; the third-stage capture agent containing an extractant is circulated as a third-stage capture agent and is continuously mixed with the fresh second-stage raffinate and then allowed to stand for clarification and separation, the third-stage raffinate is allowed to stand for clarification and separation, the obtained oil phase is returned to the third extractant recovery stage, and the obtained water phase is discharged to enter the next process;

[0049] S2. After 30 days and 90 days of operation, the concentration of the extractant in the first-stage extractant-containing capture agent can reach 1 / 3 and 1.08 times the extractant concentration value in the extraction system, respectively. The first-stage extractant-containing capture agent is returned to the extraction system for extraction, and the capture agent of each subsequent stage is used as the capture agent of the previous stage. A new extraction system diluent is added as a capture agent in the third extractant recovery stage, and then the extractant is captured and recovered using the method of step S1. The results show that after the capture agent is reused, there is no obvious abnormality in the extraction system, the raffinate discharged basically does not contain the extractant, the light transmittance is significantly improved, and it will not cause adverse effects on the next process.

[0050] Example 2

[0051] This embodiment adopts a two-stage cycle to capture the extractant (i.e., n=2), wherein the extractant recovery device used in each stage has Figure 2 The structure shown includes a mixing chamber 21, a static separation chamber 22 and a capture agent reflux dark channel 23. The outlet of the mixing chamber 21 is connected to the inlet of the static separation chamber 22. The outlet of the static separation chamber 22 is connected to the inlet of the mixing chamber 21 through the capture agent reflux dark channel 23 under the action of the reflux regulating pipe 24 to form a capture agent circulation loop.

[0052] (1) Extraction agent clarification and recovery:

[0053] The pH value of the raffinate to be recovered (containing the diluent Escaid 110, the extractant C272, and the concentration of the extractant being 0.6 mol / l) was adjusted by using H + The concentration of 10 mol / L hydrochloric acid is adjusted to 4, and then allowed to stand for clarification and separation to obtain floating oil and clarified raffinate, and the floating oil is returned to the extraction system for extraction;

[0054] (2) Extractant recycling capture and recovery:

[0055] S1, the clarified raffinate enters the first extractant recovery stage, and adopts Figure 2 The circulated capture agent in the manner shown is mixed and then allowed to stand for clarification and separation to obtain a first-stage capture agent containing an extractant and a first-stage raffinate; the first-stage capture agent containing an extractant is circulated as a first-stage capture agent and is further mixed with the fresh clarified raffinate and then allowed to stand for clarification and separation, and the first-stage raffinate enters the second extractant recovery stage and is then mixed with the first-stage raffinate using Figure 2 After the circulated capture agent is mixed, it is allowed to stand for clarification and separation to obtain a second-stage capture agent containing an extractant and a second-stage raffinate; the second-stage capture agent containing an extractant is circulated as a second-stage capture agent and is continuously mixed with the fresh first-stage raffinate and then allowed to stand for clarification and separation, the second-stage raffinate is allowed to stand for clarification and separation, the obtained oil phase is returned to the second extractant recovery stage, and the obtained water phase is discharged to enter the next process;

[0056] S2. After 30 days and 90 days of operation, the concentration of the extractant in the first-stage extractant-containing capture agent can reach 0.2 and 0.78 times the extractant concentration value in the extraction system, respectively. The first-stage extractant-containing capture agent is returned to the extraction system for extraction, and the capture agent of each subsequent stage is used as the capture agent of the previous stage. A new extraction system diluent is added as a capture agent in the second extractant recovery stage, and then the extractant is captured and recovered by the method of step S1. The results show that after the capture agent is reused, there is no obvious abnormality in the extraction system, the effluent raffinate basically does not contain the extractant, the transmittance is significantly improved, and it will not cause adverse effects on the next process.

[0057] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention without departing from the principles and intent of the present invention.

Claims

1. A device for recovering an extractant from a raffinate, characterized in that: The equipment comprises a pH value regulating device and an extractant recovery device; the extractant recovery device comprises a first-stage extractant clarifier, an n-stage extractant recovery device and a final-stage extractant clarifier, where n is greater than or equal to 2, a material outlet of the pH value regulating device is communicated with a material inlet of the first-stage extractant clarifier, a water phase outlet of the first-stage extractant clarifier is communicated with a material inlet of a first-stage extractant recovery device, and an oil phase outlet of the first-stage extractant clarifier is communicated with an extraction system; each stage of the n-stage extractant recovery devices is provided with a capture agent circulation loop, a raffinate outlet of each stage of the extractant recovery device is communicated with a material inlet of a next-stage extractant recovery device, and a capture agent outlet of each stage of the extractant recovery device is communicated with a material inlet of an upper-stage extractant recovery device; a raffinate outlet of the final-stage extractant recovery device is communicated with a material inlet of a final-stage extractant clarifier, and an oil phase outlet of the final-stage extractant clarifier is communicated with a material inlet of the final-stage extractant recovery device.

2. The device for recovering an extractant from a raffinate according to claim 1, characterized in that: Each extractant recoverer in the n-stage extractant recoverer independently has the first structure or the second structure: The first structure: the extractant recovery device comprises a mixing chamber, a static separation chamber and a capture agent circulation tank, the outlet of the mixing chamber is connected to the inlet of the static separation chamber, and the static separation chamber, the capture agent circulation tank and the mixing chamber are connected in sequence under the action of a circulation pump to form a capture agent circulation loop; The second structure: the extractant recoverer includes a mixing chamber, a static separation chamber and a capture agent reflux dark channel, the outlet of the mixing chamber is connected to the inlet of the static separation chamber, and the outlet of the static separation chamber is connected to the inlet of the mixing chamber through the capture agent reflux dark channel under the action of the reflux regulating pipe to form a capture agent circulation loop.

3. The device for recovering an extractant from a raffinate according to claim 2, characterized in that: A stirrer is arranged in the mixing chamber.

4. A method for recovering an extractant from a raffinate, characterized in that: The method comprises the following steps: (1) Extraction agent clarification and recovery: The pH value of the raffinate to be recovered is adjusted to 1.5 to 5, and then allowed to stand for clarification and separation to obtain floating oil and clarified raffinate; (2) Extractant recycling capture and recovery: S1, the extractant in the clarified raffinate is captured and recovered by using a capture agent for more than 2 levels, after each level of capture and recovery is completed, the obtained capture agent containing the extractant is recycled as the capture agent of this level, and the obtained raffinate enters the next level of capture and recovery, the raffinate obtained after the last level of capture and recovery is statically clarified and separated, the obtained oil phase is returned to the last level of capture and recovery, and the obtained water phase is discharged; S2. When the concentration of the extractant contained in the first-stage capture agent reaches the set value, it is drawn out, and the capture agent of each subsequent stage is used as the capture agent of the previous stage. In the last stage, fresh pure diluent of the extraction system is added as the capture agent, and then the method of step S1 is used to capture and recover the extractant.

5. The method for recovering an extractant from a raffinate according to claim 4, characterized in that: The set value means that the concentration of the extractant reaches 0.2 to 2.0 times the concentration of the extractant in the extraction system.

6. The method for recovering an extractant from a raffinate according to claim 4, characterized in that: The first-stage capture agent after the floating oil and the extractant concentration reach the set value is returned to the extraction system for extraction.

7. The method for recovering an extractant from a raffinate according to claim 4, characterized in that: The method adopts n-level extractant recovery, n≥2, and the specific steps include: (1) Extraction agent clarification and recovery: The pH value of the raffinate to be recovered is adjusted to 1.5 to 5, and then allowed to stand for clarification and separation to obtain floating oil and clarified raffinate, wherein the floating oil is returned to the extraction system for extraction; (2) Extractant recycling capture and recovery: S1, the clarified raffinate enters the first extractant recovery stage and is mixed with the first-stage capture agent, and then is allowed to stand for clarification and separation, to obtain a first-stage extractant-containing capture agent and a first-stage raffinate; the first-stage extractant-containing capture agent is circulated as the first-stage capture agent and is continuously mixed with the fresh clarified raffinate, and then is allowed to stand for clarification and separation, the first-stage raffinate enters the second extractant recovery stage and is mixed with the second-stage capture agent, and then is allowed to stand for clarification and separation, to obtain a second-stage extractant-containing capture agent and a second-stage raffinate; the second-stage extractant-containing capture agent is circulated as the second-stage capture agent and is continuously mixed with the fresh first-stage raffinate, and then is allowed to stand for clarification and separation, the second-stage raffinate enters the next extractant recovery stage for extractant capture and recovery; and so on. After the n-1th stage extractant capture and recovery, an n-1th stage extractant-containing capture agent and an n-1th stage raffinate are obtained; the n-1th stage extractant-containing capture agent is circulated as an n-1th stage capture agent and is continuously mixed with a fresh n-2th stage raffinate before being allowed to stand for clarification and separation; the n-1th stage raffinate enters the nth extractant recovery stage and is mixed with the nth stage capture agent before being allowed to stand for clarification and separation, thereby obtaining an nth stage extractant-containing capture agent and an nth stage raffinate; the nth stage extractant-containing capture agent is circulated as an nth stage capture agent and is continuously mixed with a fresh n-1th stage raffinate before being allowed to stand for clarification and separation; the nth stage raffinate is allowed to stand for clarification and separation, the obtained oil phase is returned to the nth extractant recovery stage, and the obtained water phase is discharged; S2. When the concentration of the extractant in the first-stage extractant-containing capture agent reaches 0.2 to 2.0 times the extractant concentration in the extraction system, it is returned to the extraction system for extraction, and the capture agent of each subsequent stage is used as the capture agent of the previous stage. A new extraction system pure diluent is added as the capture agent at the nth extractant recovery stage, and then the extractant is captured and recovered using the method of step S1.

8. The method for recovering an extractant from a raffinate according to claim 7, characterized in that: When the first-stage extractant-containing capture agent after the floating oil and extractant concentrations reach the set values ​​is returned to the extraction system for extraction, when the extractant concentration contained therein is lower than the required value of the extractant in the extraction system, additional extractant needs to be added to increase the concentration to the required value; when the extractant concentration contained therein is higher than the required value of the extractant in the extraction system, additional diluent needs to be added to reduce the concentration to the required value.

9. The method for recovering an extractant from a raffinate according to any one of claims 4 to 8, characterized in that: The pH value of the raffinate to be recovered is adjusted to 1.5-5 using an acid as the pH adjuster, and the adjustment is performed in any of the following ways: ① the raffinate to be recovered and the acid are added to a stirring tank respectively for stirring; ② the acid and the raffinate are continuously added by a venturi tube for mixing; ③ the acid is directly added to the mixing chamber of the extraction system for stirring and mixing with the raffinate to be recovered.

10. The method for recovering an extractant from a raffinate according to any one of claims 4 to 8, characterized in that: The method is carried out in the device for recovering the extractant from the raffinate as claimed in any one of claims 1 to 3.

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