A method for the efficient separation and extraction of vanadium and molybdenum from vanadium-molybdate solution

Abstract

This invention belongs to the field of non-ferrous metal recovery technology and relates to a method for effectively separating and extracting vanadium and molybdenum from a vanadium-molybdate solution. The method includes: adjusting the pH value of the vanadium-molybdate solution and the back-extraction reagent to achieve co-extraction of vanadium and molybdenum from the leachate using an extractant organic phase, and sequential back-extraction and recovery of molybdenum and vanadium. The extractant organic phase used for vanadium and molybdenum extraction has the same composition. This invention solves the problems of difficulty in simultaneously recovering various precious metal elements, low recovery rate, low purity of recovered products, and significant environmental pollution in existing technologies. While ensuring the extraction and separation effect, this invention achieves the sequential extraction and recovery of vanadium and molybdenum from the leachate, overcoming the defects of low yield and low product purity caused by poor separation of elements in the leachate in existing technologies.

Description

Technical Field

[0001] This invention relates to the field of non-ferrous metal recycling technology, and in particular to a method for effectively separating and extracting vanadium and molybdenum from vanadium molybdate solutions. Background Technology

[0002] Vanadium and molybdenum are known as "industrial MSG" and "war metals" due to their high melting point, high hardness, and unique properties such as wear and corrosion resistance, making them widely used in aerospace, defense, and other fields. Vanadium ore, molybdenum ore, and vanadium-molybdenum-containing waste catalysts are important raw materials for extracting vanadium and molybdenum. However, because vanadium and molybdenum have very similar properties, extracting them from these raw materials is quite difficult, especially separating and extracting vanadium and molybdenum from waste vanadium-molybdenum catalysts with complex compositions.

[0003] Existing technologies commonly use ammonium salt precipitation, sulfidation, ion exchange, and solvent extraction to separate vanadium and molybdenum. Ammonium salt precipitation involves using ammonium salts to precipitate vanadium as ammonium metavanadate under controlled experimental conditions, thus achieving vanadium-molybdenum separation. However, this method cannot deeply precipitate vanadium, resulting in generally poor separation and purification, and requires large amounts of ammonium salt. Ion exchange is complex, generates large amounts of acid and alkaline wastewater, and has limited resin adsorption capacity. Existing solvent extraction methods also suffer from lengthy processes, incomplete vanadium-molybdenum separation, and insufficient product quality.

[0004] There is an urgent need in the existing technology for a method that can effectively separate and extract elements such as molybdenum and vanadium from vanadium molybdate solutions, while ensuring high yields and product purity for each element. Summary of the Invention

[0005] In view of the above analysis, the present invention aims to provide a method for effectively separating and extracting vanadium and molybdenum from vanadium molybdate solution, in order to solve at least one of the problems in the prior art, such as difficulty in simultaneously recovering various precious metal elements, low recovery rate, low purity of recovered products, and significant environmental pollution.

[0006] The objective of this invention is mainly achieved through the following technical solutions:

[0007] A method for effectively separating and extracting vanadium and molybdenum from a vanadium-molybdate solution, comprising:

[0008] Based on pH adjustment in vanadium molybdate solution, co-extraction of vanadium and molybdenum elements in organic relative leachate is achieved;

[0009] Based on pH adjustment in the back-extraction reagent, molybdenum and vanadium elements are sequentially back-extracted and recovered;

[0010] The vanadium and molybdenum elements are extracted using organic phases with the same composition.

[0011] Preferably, the method for effectively separating and extracting vanadium and molybdenum from a vanadium-molybdate solution includes:

[0012] Vanadium and molybdenum co-extraction was achieved by extracting the organic phase under acidic conditions.

[0013] Molybdenum is back-extracted under alkaline conditions to achieve separation of molybdenum from the vanadium-rich extract organic phase;

[0014] Vanadium is back-extracted in a more alkaline environment, which separates vanadium from the extracted organic phase.

[0015] Preferably, the method for effectively separating and extracting vanadium and molybdenum from a vanadium-molybdate solution includes:

[0016] S1. Obtain a vanadium molybdate solution, adjust the vanadium molybdate solution to acidity, and use an extractive organic phase to extract the vanadium molybdate solution to achieve molybdenum-vanadium co-extraction and obtain a molybdenum-vanadium-rich extractive organic phase;

[0017] S2. Add back-extraction reagent to back-extract molybdenum, adjust the back-extraction reagent to alkaline, and use the back-extraction reagent to back-extract the molybdenum-vanadium-rich organic phase to obtain a vanadium-rich organic phase and a molybdenum-rich back-extraction solution.

[0018] S3. Add a back-extraction reagent to back-extract vanadium, adjust the back-extraction reagent to a stronger alkalinity than the back-extraction reagent in step S2, and back-extract the vanadium-rich organic compound to obtain a vanadium-rich back-extraction solution.

[0019] S4. The vanadium-rich back-extraction solution and the molybdenum-rich back-extraction solution are processed independently to obtain vanadium and molybdenum products.

[0020] Preferably, the pH value of the leachate required for the co-extraction of vanadium and molybdenum is 3 to 4.

[0021] Preferably, the pH value of the back-extraction reagent required for back-extraction of molybdenum is 8-9.

[0022] Preferably, the pH value of the back-extraction reagent required for vanadium back-extraction is >12.

[0023] Preferably, before S2, there is a step of washing and removing impurities from the molybdenum-vanadium-rich extract organic phase and mixing the refluxed wash water with a vanadium-molybdate solution adjusted to acidity as the aqueous phase feed liquid for the extraction section.

[0024] An application for the efficient separation and extraction of vanadium and molybdenum from a vanadium-molybdate solution, using the aforementioned method for the efficient separation and extraction of vanadium and molybdenum from a vanadium-molybdate solution. A method for recovering molybdenum and vanadium from spent HDS catalyst, in addition to the aforementioned method for the efficient separation and extraction of vanadium and molybdenum from a vanadium-molybdate solution, further includes using an HDS spent catalyst leachate prepared by leaching the spent HDS catalyst as a vanadium-molybdate solution. A system for recovering molybdenum and vanadium from spent HDS catalyst, used in the aforementioned method for the efficient separation and extraction of vanadium and molybdenum from a vanadium-molybdate solution or the aforementioned method for recovering molybdenum and vanadium from spent HDS catalyst, includes: a pretreatment subsystem, an extraction unit, a reverse molybdenum unit, a reverse vanadium unit, and a regeneration unit connected sequentially from upstream to downstream of the material feed direction, with the outlet of the upstream unit connected to the inlet of the adjacent downstream unit.

[0025] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0026] (1) This invention achieves high selectivity for both vanadium and molybdenum in the extraction of organic compounds by adjusting the pH value in the leachate, thus separating vanadium and molybdenum from impurities; it improves the separation effect of vanadium and molybdenum from impurities and increases purity; the recovery rate of molybdenum is greater than 99.5%, preferably greater than 99.75%; the mass fraction of molybdate in the solid after evaporation, concentration and crystallization is greater than 99.5%, preferably greater than 99.58%; the recovery rate of vanadium is greater than 99.5%, preferably greater than 99.82%; the mass fraction of vanadate in the solid after evaporation, concentration and crystallization is greater than 99.5%, preferably greater than 99.59%.

[0027] (2) This invention achieves selective changes in the vanadium and molybdenum elements of the same extracted organic relative by further adjusting the pH value in the back-extraction reagent. While ensuring the extraction and separation effect, it realizes the sequential back-extraction and recovery of molybdenum and vanadium in the leachate. At the same time, it overcomes the defects of low yield and low product purity caused by the poor separation effect of each element in the leachate in the existing technology.

[0028] (3) The present invention uses the reflux of the raffinate to prepare a vanadium molybdate solution. On the one hand, it avoids the waste of vanadium and molybdenum elements and improves the yield of vanadium and molybdenum elements; on the other hand, it achieves the enrichment of a variety of precious metal elements during the reflux of the raffinate, which facilitates the recovery of precious metal elements; at the same time, it reduces waste liquid discharge, environmental pollution and cost.

[0029] (4) This invention uses the same extraction organic phase to achieve extraction of two elements, avoiding pollution caused by the residual extraction phase in the raffinate when different elements use different extraction systems; at the same time, since the extraction organic phase is the same, the extraction organic phase after back-extraction can be recycled and reused without worrying about mutual contamination of the extraction systems, thus reducing waste liquid discharge and environmental pollution.

[0030] (5) By controlling the pH value during washing and purifying the extract phase, the present invention removes impurities while reducing the elution of molybdenum and vanadium during washing and purification, thereby increasing the yield of both elements.

[0031] In this invention, the above-described technical solutions can be combined with each other to achieve more preferred combinations. Other features and advantages of this invention will be set forth in the following description, and some advantages may become apparent from the description or be learned by practicing the invention. The objects and other advantages of this invention can be realized and obtained through the embodiments described and the accompanying drawings, which are particularly pointed out. Attached Figure Description

[0032] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts.

[0033] Figure 1 This is a process flow diagram of the method for effectively separating and extracting vanadium and molybdenum from a vanadium molybdate solution according to the present invention.

[0034] Figure 2 This is a schematic diagram of the system for effectively separating and extracting vanadium and molybdenum from a vanadium-molybdate solution according to the present invention. Detailed Implementation

[0035] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which constitute a part of the present invention and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not intended to limit the scope of the present invention.

[0036] On one hand, this invention discloses a method for effectively separating and extracting vanadium and molybdenum from a vanadium-molybdate solution, comprising:

[0037] Based on pH adjustment in vanadium molybdate solution, co-extraction of vanadium and molybdenum elements in organic relative leachate is achieved;

[0038] Based on pH adjustment in the back-extraction reagent, molybdenum and vanadium elements are sequentially back-extracted and recovered;

[0039] The vanadium and molybdenum elements are extracted using organic phases with the same composition.

[0040] In practice, this invention preferentially achieves co-extraction of vanadium and molybdenum in an acidic environment, and sequentially back-extracts molybdenum and vanadium in an alkaline environment to achieve separation of molybdenum and vanadium.

[0041] Specifically, the method for effectively separating and extracting vanadium and molybdenum from a vanadium-molybdate solution includes:

[0042] Vanadium and molybdenum co-extraction was achieved by extracting the organic phase under acidic conditions.

[0043] Molybdenum is back-extracted under alkaline conditions to achieve separation of molybdenum from the vanadium-rich extract organic phase;

[0044] Back-extraction in a more alkaline environment separates vanadium from the extracted organic phase.

[0045] Compared with existing technologies, this invention achieves high selectivity for both vanadium and molybdenum in the extraction of organic compounds by adjusting the pH value in the leachate, thus separating vanadium and molybdenum from impurities; improving the separation effect of vanadium and molybdenum from impurities and increasing purity.

[0046] Compared with the prior art, the present invention realizes the selective change of the same extraction organic phase for vanadium and molybdenum elements by further adjusting the pH value in the stripping reagent. While ensuring the extraction separation effect, the sequential stripping and recovery of molybdenum and vanadium in the leaching solution are achieved, and at the same time, the defects of low yield and low product purity caused by the poor separation effect of each element in the leaching solution in the prior art are overcome.

[0047] It should be noted that the present invention realizes the extraction of two elements by using the same extraction organic phase, avoiding the pollution caused by the residual extraction phase in the raffinate when different extraction systems are used for different elements; at the same time, due to the same extraction organic phase, the extraction organic phase after stripping treatment can be recycled without worrying about mutual pollution of the extraction systems, reducing the waste liquid discharge and environmental pollution.

[0048] Preferably, the pH value of the leaching solution required for the co-extraction of vanadium and molybdenum elements is 3-4.

[0049] It should be noted that the applicant's research found that: when the pH value is 2-9, vanadium in the leaching solution exists in the forms of V4O 12 4- , V3O9 3- , V2O7 4- , VO3 - and various polymeric polyacid anions, such as HV 10 O 28 5- , H2V 10 O 28 4- etc. The extraction organic phase has extremely high extraction selectivity for its existing forms, while when the pH value < 2 and the pH value > 10, the extraction rate of vanadium by the extraction organic phase drops significantly; when the pH value < 4, molybdenum in the molybdenum-rich raffinate exists in various polymeric polyacid anions, such as Mo2O7 2- , Mo3O 10 2- , Mo4O 13 2- , Mo7O 24 6- (or HMo7O 24 5- , H3Mo7O 24 3- ), Mo8O 26 4- and the form of cationic polymer under strong acidic conditions. The extraction organic phase has extremely high extraction selectivity for its various polymeric polyacid anions, while when 4 < pH < 8, the extraction rate of molybdenum by the extraction organic phase gradually decreases, and when pH > 8, the extraction rate of molybdenum by the extraction organic phase drops significantly. Therefore, when the pH value of the leaching solution is 3-4, the extraction organic phase has good selectivity for both molybdenum and vanadium, and the co-extraction of the two elements can be achieved.

[0050] Specifically, the extractable organic phase includes quaternary ammonium salt extractants or a mixture of quaternary ammonium salt extractants and tertiary amine extractants.

[0051] Preferably, the volume ratio of quaternary ammonium salt extractant to tertiary amine extractant is 1.5 to 4:1.

[0052] Preferably, the tertiary amine extractant is one or more of the following: a tertiary amine with substituents of C8 to C10, a tertiary amine with substituents of isooctyl, and N2O8.

[0053] Preferably, the tertiary amine of C8 to C10 in the substituent is any one of N235, Alamine336, Adogen364, HostarexA327, and TOA.

[0054] Preferably, the tertiary amine with isooctyl substituent is any one of Adogen381, Alamine308, HostarexA324, and Adogen382.

[0055] Preferably, the quaternary ammonium salt extractant is one or more of N263, Aliquat336, TOMAC and Adogen464.

[0056] Preferably, the extracted organic phase also includes an alcohol phase modifier with 7 to 10 carbon atoms.

[0057] Specifically, the alcohol phase modifier can be one or more of n-heptanol, n-octanol, sec-octanol, isooctanol, n-decanol, etc.

[0058] It should be noted that alcohol phase modifiers can improve the performance of the extraction system and increase extraction efficiency; they can also reduce the water solubility of the extraction system and reduce extractant loss; in addition, they can optimize the extraction system and prevent emulsification and the formation of a third phase.

[0059] It should be noted that alcohol phase modifiers with 7 to 10 carbon atoms have the advantages of high fluidity, low water solubility, and low cost.

[0060] Preferably, the extraction organic phase also includes a low-viscosity diluent to improve the relative fluidity of the organic phase and the aqueous phase during extraction, thereby enhancing contact and ion exchange effects.

[0061] Preferably, the diluent can be 260# solvent oil.

[0062] Specifically, the volume ratio of extractant, phase modifier, and diluent in the extracted organic phase satisfies the following: extractant 10–40%; phase modifier 5–20%; diluent 40–85%.

[0063] Specifically, the volume fraction of the extractant in the organic phase can be 10%, 12%, 14%, 15%, 16%, 18%, 20%, 21%, 22%, 24%, 25%, 26%, 28%, 30%, 32%, 33%, 34%, 35%, 37%, 38%, 39%, or 40%.

[0064] Specifically, the volume fraction of the phase modifier in the extracted organic phase can be 5%, 6%, 7%, 8%, 9%, 10%, 12%, 14%, 15%, 16%, 18%, or 20%.

[0065] Specifically, the volume fraction of the diluent in the extracted organic phase can be 40%, 42%, 43%, 44%, 45%, 47%, 48%, 49%, 50%, 50%, 52%, 53%, 54%, 55%, 57%, 58%, 59%, 60%, 60%, 62%, 63%, 64%, 65%, 67%, 68%, 69%, 70%, 72%, 73%, 74%, 75%, 77%, 78%, 79%, 80%, 82%, 83%, 84%, or 85%.

[0066] Preferably, the pH value of the back-extraction reagent required for back-extraction of molybdenum is 8-9.

[0067] Preferably, the pH value of the back-extraction reagent required for vanadium back-extraction is >12.

[0068] Regarding the back-extraction process, it should be noted that the back-extraction process is a process in which the extracting organic phase competes with the back-extraction reagent for the target ions:

[0069] The extraction system has different extraction capabilities at different pH levels, and therefore its competitiveness and selectivity for different ions vary at different pH levels.

[0070] At a pH of 8-9, the affinity of the extraction system of the present invention for molybdenum ions is less than that of the stripping reagent for molybdenum ions, while the affinity of the extraction system of the present invention for vanadium ions is greater than that of the stripping reagent for vanadium ions. Therefore, it is possible to achieve the stripping of molybdenum and the separation of molybdenum and vanadium.

[0071] When the pH value is >12, the affinity of the extraction system of the present invention for vanadium ions is less than that of the stripping reagent for vanadium ions, thus enabling the stripping of vanadium.

[0072] Specifically, such as Figure 1 As shown, the method for effectively separating and extracting vanadium and molybdenum from a vanadium-molybdate solution includes:

[0073] S1. Obtain a vanadium molybdate solution, adjust the vanadium molybdate solution to acidity, and use an extractive organic phase to extract the vanadium molybdate solution to achieve molybdenum-vanadium co-extraction and obtain a molybdenum-vanadium-rich extractive organic phase;

[0074] S2. Add back-extraction reagent to back-extract molybdenum, adjust the back-extraction reagent to alkaline, and use the back-extraction reagent to back-extract the molybdenum-vanadium-rich organic phase to obtain a vanadium-rich organic phase and a molybdenum-rich back-extraction solution.

[0075] S3. Add a back-extraction reagent to back-extract vanadium, adjust the back-extraction reagent to a stronger alkalinity than the back-extraction reagent in step S2, and back-extract the vanadium-rich organic compound to obtain a vanadium-rich back-extraction solution.

[0076] S4. The vanadium-rich back-extraction solution and the molybdenum-rich back-extraction solution are processed independently to obtain vanadium and molybdenum products.

[0077] Specifically, the pH of the vanadium molybdate solution in S1 is adjusted to 3-4.

[0078] Specifically, the extraction ratio in S1 is O / A = 1:5 to 5:1, and the number of extraction stages is 2 to 5.

[0079] Specifically, in S2, the pH of the back-extraction reagent is adjusted to 8-9.

[0080] Specifically, the ratio of molybdenum back-extracted in S2 is O / A = 1 to 10:1, and the number of stages is 2 to 8.

[0081] Specifically, in S3, the pH of the back-extraction reagent is adjusted to >12.

[0082] Specifically, the ratio of vanadium back-extraction in S3 is O / A = 1 to 10:1, and the number of back-extraction stages is 2 to 5.

[0083] Preferably, before S2, there is a step of washing and removing impurities from the molybdenum-vanadium-rich extract organic phase and mixing the refluxed wash water with a vanadium-molybdate solution adjusted to acidity as the aqueous phase feed liquid for the extraction section.

[0084] Specifically, the pH value of the detergent is greater than or equal to the pH value adjusted by the vanadium molybdate solution in step S1.

[0085] Preferably, the detergent has a pH value of 4 to 4.5.

[0086] Preferably, the detergent is a sulfuric acid solution.

[0087] Specifically, when washing and removing impurities from the organic phase during molybdenum-vanadium extraction, the ratio of O / A is 5 to 15 / 1, and the number of stages is 1 to 5.

[0088] Preferably, after S2, there is a step of vanadium-rich extraction to purify and remove impurities from the organic phase, and then the effluent is adjusted to pH value and returned to the water phase inlet of the washing section for use as a detergent.

[0089] Specifically, the purifying agent for the vanadium-rich extraction of the organic phase is an aqueous sulfate solution.

[0090] Specifically, during the purification and impurity removal of the organic phase extracted with vanadium, the O / A ratio is 5 to 15:1, and the number of stages is 1 to 5.

[0091] Specifically, the pH value of the purifying agent for extracting the organic phase with vanadium is ≥ the pH value of the back-extraction reagent used for back-extracting molybdenum in S2.

[0092] Preferably, the pH value of the purifying agent for extracting the vanadium-rich organic phase can be selected as 9-10.

[0093] It should be noted that within this pH range, while ensuring a relatively low elution efficiency for vanadium, molybdenum entrained in the vanadium-rich organic phase can be effectively washed away, which is beneficial for enriching and purifying the downstream vanadium-rich back-extraction solution. When pH < 9, incomplete elution of molybdenum may occur in the vanadium-rich organic phase, leading to a decrease in the purity of the vanadium-rich back-extraction solution; when pH > 10, vanadium in the vanadium-rich organic phase will exhibit a high elution rate, resulting in a decrease in vanadium yield.

[0094] Preferably, the method for effectively separating and extracting vanadium and molybdenum from a vanadium-molybdate solution further includes:

[0095] The blank organic phase obtained from S4 back-extraction was washed and regenerated with water and used as the reflux for extraction organic phase.

[0096] Specifically, the ratio of O / A to O / A in the blank organic phase water washing regeneration is 5 to 20:1, and the number of stages is 1 to 2.

[0097] Preferably, S1 further includes:

[0098] S0. The organic phase of the extract is treated with acid to remove inorganic impurities and obtain activated quaternary ammonium salt.

[0099] Specifically, S0 includes:

[0100] S001. Mix the extractant, phase modifier, and diluent evenly according to the set volume ratio to obtain the extractable organic phase;

[0101] S002. The extracted organic phase obtained in S001 is washed with a sulfuric acid solution of 1 mol / L to 2 mol / L.

[0102] S003. Further wash the extracted organic phase treated with S002 until it is neutral.

[0103] Preferably, the method for effectively separating and extracting vanadium and molybdenum from a vanadium-molybdate solution further includes:

[0104] S5. The raffinate is refluxed to prepare a vanadium-molybdate solution, recovering the unextracted vanadium and molybdenum, and concentrating the remaining precious metals except for vanadium and molybdenum.

[0105] During implementation, the unextracted vanadium and molybdenum further participate in the extraction of vanadium and molybdenum, avoiding the waste of vanadium and molybdenum elements and helping to improve the yield of vanadium and molybdenum elements; at the same time, the other metal elements in the leachate, except for vanadium and molybdenum, are not extracted by the organic phase and accumulate continuously during the reflux process of the raffinate, realizing the enrichment of multiple precious metal elements and providing high-grade raw materials for the recovery of other precious metal elements.

[0106] Compared with the prior art, the present invention uses the reflux of the raffinate to prepare a vanadium-molybdate solution. On the one hand, this avoids the waste of vanadium and molybdenum elements and improves the yield of vanadium and molybdenum elements. On the other hand, the reflux of the raffinate achieves the enrichment of various precious metal elements, which facilitates the recovery of precious metal elements.

[0107] Secondly, this invention discloses an application for the effective separation and extraction of vanadium and molybdenum from a vanadium-molybdate solution, using the above-described method for the effective separation and extraction of vanadium and molybdenum from a vanadium-molybdate solution.

[0108] Thirdly, the present invention discloses a method for recovering molybdenum and vanadium from HDS waste catalyst, which, in addition to the above-mentioned method for effectively separating and extracting vanadium and molybdenum from vanadium molybdate solution, also includes: using HDS waste catalyst leachate prepared by leaching HDS waste catalyst as vanadium molybdate solution.

[0109] Fourthly, the present invention discloses a system for effectively separating and extracting vanadium and molybdenum from a vanadium molybdate solution, comprising: a pretreatment subsystem, an extraction unit, a reverse molybdenum unit, a reverse vanadium unit, and a regeneration unit connected sequentially in the direction of material feeding from upstream to downstream, wherein the outlet of the upstream unit is connected to the inlet of the adjacent downstream unit.

[0110] Specifically, the inlet of the extraction unit is connected to the outlet of the pretreatment subsystem; the extraction unit contains two flow controllers, which control the flow rates of the extracted organic phase and the pretreated vanadium molybdate solution, respectively; the extraction unit contains 2 to 5 centrifugal extractors connected in series for multi-stage countercurrent extraction.

[0111] During implementation, a centrifugal extractor is used to extract the separated molybdenum- and vanadium-rich organic phase and raffinate.

[0112] Specifically, the outlet of the molybdenum-vanadium-rich extraction organic phase of the extraction unit is connected to the inlet of the molybdenum-reverse unit. The molybdenum-reverse unit includes two flow controllers, which control the feed flow of the molybdenum-vanadium-rich extraction organic phase and the back-extraction agent used for molybdenum back-extraction, respectively. The molybdenum-reverse unit also includes 2 to 8 centrifugal extractors connected in series for multi-stage countercurrent back-extraction.

[0113] During implementation, the centrifugal extractor in the molybdenum back-extraction unit extracts vanadium-rich organic phase and molybdenum-rich back-extraction solution separately.

[0114] Specifically, the outlet of the vanadium-rich extraction organic phase of the molybdenum-reverse unit is connected to the inlet of the vanadium-reverse unit. The vanadium-reverse unit contains two flow controllers, which control the feed flow rates of the vanadium-rich extraction organic phase and the vanadium back-extraction agent, respectively. The vanadium-reverse unit also includes 2 to 5 centrifugal extractors connected in series for multi-stage countercurrent back-extraction.

[0115] During implementation, the centrifugal extractor in the vanadium-reverse unit extracts the separated blank extract organic phase and the vanadium-rich back-extraction solution.

[0116] Specifically, the regeneration unit includes two flow controllers to control the flow rates of the blank organic phase and pure water feed, respectively; the regeneration unit also includes one or two centrifugal extractors connected in series for multi-stage countercurrent regeneration.

[0117] During implementation, the centrifugal extractor in the regeneration unit centrifuges extracts recycled organic phase and regenerated water, with the outlet of the recycled organic phase connected to the extraction unit.

[0118] Preferably, a washing unit is provided between the extraction unit and the reverse molybdenum unit, the inlet of the molybdenum-vanadium-rich extraction organic phase is connected to the outlet of the molybdenum-vanadium-rich extraction organic phase of the extraction unit, and the outlet of the molybdenum-vanadium-rich extraction organic phase is connected to the inlet of the reverse molybdenum unit.

[0119] Specifically, the washing unit includes two flow controllers, which control the flow rates of the vanadium-molybdenum-rich extraction organic phase and the detergent feed, respectively; the washing unit includes 1 to 5 centrifugal extractors connected in series for multi-stage countercurrent washing.

[0120] During implementation, the washing unit purifies the vanadium-molybdenum-rich extract organic phase and removes impurities from the organic phase.

[0121] Preferably, a purification unit is provided between the anti-molybdenum unit and the anti-vanadium unit, with the inlet of the purification unit connected to the outlet of the molybdenum- and vanadium-rich extract organic phase of the anti-molybdenum unit; and the outlet of the purification unit connected to the inlet of the anti-vanadium unit.

[0122] Specifically, the purification unit includes two flow controllers, which control the flow rates of the vanadium-rich extraction organic phase and the purification agent feed, respectively; the purification unit includes 1 to 5 centrifugal extractors connected in series for multi-stage countercurrent purification.

[0123] Fifthly, the present invention discloses an application of a method for effectively separating and extracting vanadium and molybdenum from a vanadium-molybdate solution, including: separation of vanadium and molybdenum elements from HDS waste catalyst or vanadium-molybdenum lead ore leaching solution.

[0124] Specifically, the HDS spent catalyst or vanadium-molybdenum-lead ore and its leachate described in this invention meet the requirements of Table 1:

[0125] Table 1. Composition of HDS waste catalyst or vanadium-molybdenum-lead ore and its leachate.

[0126]

[0127]

[0128] Example 1

[0129] This embodiment discloses a method for recovering molybdenum and vanadium from a vanadium molybdate solution, such as... Figure 1 As shown, it includes:

[0130] 1. Vanadium-molybdate solution pretreatment: The vanadium-molybdate solution is obtained by alkaline leaching of HDS waste catalyst and conventional industrial impurity removal. The pH of the leachate is adjusted to 3.8 using concentrated sulfuric acid. The Mo content in the leachate is 11.3 g / L and the V content is 6.9 g / L.

[0131] 2. Organic phase pretreatment: The organic phase is a mixture of 5% Alamine 336, 20% N263, 10% 2-octanol and 65% 260# solvent oil by volume. The organic phase is treated 6 times with 2 mol / L sulfuric acid solution at a ratio O / A = 1 / 1, and then washed with deionized water until it is near neutral.

[0132] 3. Extraction: The pretreated organic phase was mixed with the pretreated leachate at a ratio of O / A = 1.3 / 1 for extraction. The extraction stage was 3 stages to obtain vanadium-molybdenum loaded 1 and raffinate, wherein the raffinate contained 6 ppm of vanadium and 13 ppm of molybdenum.

[0133] 4. Washing: The washing agent used is a dilute sulfuric acid solution with a pH of 4.2. The washing ratio O / A = 10 / 1, and the washing stage is 3 stages. Vanadium-molybdenum loaded 2 and wash water are obtained. The wash water is refluxed to the aqueous phase inlet of the extraction section and enters the extraction section together with the leachate after pretreatment.

[0134] 5. Molybdenum back-extraction: The reaction agent used for molybdenum back-extraction is a sodium sulfate solution with a pH of 8.7 and a sodium sulfate concentration of 0.15 mol / L. The ratio of O / A is 5 / 1, and the number of stages is 6. Vanadium-loaded solution 1 and molybdenum-rich back-extraction solution are obtained. The molybdenum concentration in the molybdenum-rich back-extraction solution is 43.41 g / L, corresponding to a molybdenum recovery rate of 99.88%. The mass fraction of molybdate in the solid after evaporation, concentration and crystallization is 99.62%.

[0135] 6. Purification: The purification agent used is a sodium sulfate solution with a pH of 9.6 and a sodium sulfate concentration of 0.05 mol / L. Compared with O / A = 10 / 1, the purification stage is 3 stages, resulting in vanadium-loaded 2 and purified liquid. After adjusting the pH, the purified liquid is returned to the water phase inlet of the washing section as a washing agent and recycled.

[0136] 7. Vanadium back-extraction: The reaction agent used for vanadium back-extraction is a sodium sulfate solution with a pH of 12.8 and a sodium sulfate concentration of 0.15 mol / L. The ratio of O / A is 5 / 1, and the number of stages is 3. A blank organic phase and a vanadium-rich back-extraction solution are obtained. The vanadium concentration in the vanadium-rich back-extraction solution is 26.52 g / L, corresponding to a vanadium recovery rate of 99.91%. The mass fraction of vanadate in the solid after evaporation, concentration and crystallization is 99.59%.

[0137] 8. Regeneration: The regenerant used in the regeneration section is pure water. Compared with O / A = 6 / 1, the regeneration stage is 1. The regenerated organic phase is recycled. There is no need to repeat the organic phase pretreatment. It can be directly returned to the organic phase inlet of the extraction section for recycling.

[0138] This embodiment discloses an application of effectively separating and extracting vanadium and molybdenum from a vanadium-molybdate solution, using the above-described method for effectively separating and extracting vanadium and molybdenum from a vanadium-molybdate solution.

[0139] This embodiment discloses a method for recovering molybdenum and vanadium from HDS waste catalyst. In addition to the above-mentioned method for effectively separating and extracting vanadium and molybdenum from vanadium molybdate solution, it also includes: using HDS waste catalyst leachate prepared by leaching HDS waste catalyst as vanadium molybdate solution.

[0140] This embodiment discloses a system for effectively separating and extracting vanadium and molybdenum from a vanadium-molybdate solution. The method for recovering molybdenum and vanadium from a vanadium-molybdate solution using this embodiment is as follows: Figure 2 As shown, it includes: a pretreatment subsystem, an extraction unit, a molybdenum reaction unit, a vanadium reaction unit, and a regeneration unit connected sequentially from upstream to downstream of the material feed direction, with the outlet of the upstream unit connected to the inlet of the adjacent downstream unit.

[0141] The inlet of the extraction unit is connected to the outlet of the pretreatment subsystem; the extraction unit contains two flow controllers, which control the flow rates of the extracted organic phase and the pretreated vanadium molybdate solution, respectively; the extraction unit contains three centrifugal extractors connected in series for multi-stage countercurrent extraction.

[0142] Centrifugal extraction was performed to obtain the separated vanadium-molybdenum loaded 1 and raffinate.

[0143] The outlet of the vanadium-molybdenum loading 1 in the extraction unit is connected to the inlet of the reverse molybdenum unit. The reverse molybdenum unit includes two flow controllers, which control the feed flow rates of the vanadium-molybdenum loading 1 and the stripping agent used for molybdenum stripping, respectively. The reverse molybdenum unit also includes six centrifugal extractors connected in series for multi-stage countercurrent stripping. In the reverse molybdenum unit, the centrifugal extractors extract the separated vanadium-molybdenum loading 1 and the molybdenum-rich stripping solution through centrifugal extraction.

[0144] The outlet of the vanadium-containing load 1 in the molybdenum reverse extraction unit is connected to the inlet of the vanadium reverse extraction unit. The vanadium reverse extraction unit includes two flow controllers, which control the feed flow rates of the vanadium-containing load 1 and the stripping agent used for vanadium stripping, respectively. The vanadium reverse extraction unit also includes three centrifugal extractors connected in series for multi-stage countercurrent stripping. In the vanadium reverse extraction unit, the centrifugal extractors extract and separate the blank organic phase and the vanadium-rich stripping solution.

[0145] The regeneration unit includes two flow controllers to control the feed flow rates of the blank organic phase and pure water, respectively. The regeneration unit also includes a centrifugal extractor connected in series for multi-stage countercurrent regeneration. The centrifugal extractor in the regeneration unit centrifuges and extracts the circulating organic phase and regenerated water, with the circulating organic phase outlet connected to the extraction unit.

[0146] A washing unit is provided between the extraction unit and the reverse molybdenum unit. The inlet of the vanadium-molybdenum load 2 of the washing unit is connected to the outlet of the vanadium-molybdenum load 1 of the extraction unit; the outlet of the vanadium-molybdenum load 2 is connected to the inlet of the reverse molybdenum unit.

[0147] The washing unit includes two flow controllers to control the flow rates of the vanadium-molybdenum-containing load 1 and the detergent feed, respectively; the washing unit also includes three centrifugal extractors connected in series for multi-stage countercurrent washing. The washing unit purifies the vanadium-molybdenum-containing load 1 and removes impurities from the organic phase.

[0148] A purification unit is provided between the molybdenum counter and the vanadium counter. The inlet of the vanadium-containing load 2 of the purification unit is connected to the outlet of the vanadium-containing load 1 of the molybdenum counter; the outlet of the vanadium-containing load 2 is connected to the inlet of the vanadium counter.

[0149] The purification unit includes two flow controllers, which control the flow rates of the vanadium-containing load 1 and the purification agent feed, respectively; the purification unit includes three centrifugal extractors connected in series for multi-stage countercurrent purification.

[0150] Example 2

[0151] This embodiment discloses a method for recovering molybdenum and vanadium from a vanadium molybdate solution, such as... Figure 1 As shown, it includes:

[0152] 1. Vanadomolybdate solution pretreatment: The vanadium-molybdate solution is the solution obtained after recovering Pb from vanadium-molybdenum-lead ore by acid leaching and conventional industrial impurity removal. The pH of the leaching solution is adjusted to 3.5 using concentrated sulfuric acid. The Mo content in the leaching solution is 9.3 g / L and the V content is 13.2 g / L.

[0153] 2. Organic phase pretreatment: The organic phase is a mixture of 10% Alamine 308, 15% Aliquat 336, 10% n-decyl alcohol and 65% 260# solvent oil by volume. The organic phase is treated 6 times with 1.5 mol / L sulfuric acid solution at a ratio O / A = 1 / 1, and then washed with deionized water until it is near neutral.

[0154] 3. Extraction: The pretreated organic phase was mixed with the pretreated leachate at a ratio of O / A = 1.5 / 1 for extraction. The extraction stage was 4 stages to obtain vanadium-molybdenum loaded 1 and raffinate, wherein the raffinate contained 10 ppm vanadium and 12 ppm molybdenum.

[0155] 4. Washing: The washing agent used is a dilute sulfuric acid solution with a pH of 4.3. The washing ratio O / A = 8 / 1, and the washing stage is 4 stages. Vanadium-molybdenum loaded 2 and wash water are obtained. The wash water is refluxed to the aqueous phase inlet of the extraction section and enters the extraction section together with the leachate after pretreatment.

[0156] 5. Molybdenum back-extraction: The reaction agent used for molybdenum back-extraction is a sodium sulfate solution with a pH of 8.5 and a sodium sulfate concentration of 0.1 mol / L. The ratio of O / A is 6 / 1, and the number of stages is 5. Vanadium-loaded solution 1 and molybdenum-rich back-extraction solution are obtained. The molybdenum concentration in the molybdenum-rich back-extraction solution is 37.15 g / L, corresponding to a molybdenum recovery rate of 99.87%. The mass fraction of molybdate in the solid after evaporation, concentration and crystallization is 99.58%.

[0157] 6. Purification: The purification agent used is a sodium sulfate solution with a pH of 9.5 and a sodium sulfate concentration of 0.05 mol / L. The ratio of O / A is 8 / 1, and the purification stage is 4 stages, resulting in vanadium-loaded 2 and purified liquid. After adjusting the pH, the purified liquid is returned to the water phase inlet of the washing section as a washing agent and is recycled.

[0158] 7. Vanadium back-extraction: The reaction agent used for vanadium back-extraction is a sodium sulfate solution with a pH of 13.5 and a sodium sulfate concentration of 0.1 mol / L. The ratio of O / A is 4 / 1, and the number of stages is 4. A blank organic phase and a vanadium-rich back-extraction solution are obtained. The vanadium concentration in the vanadium-rich back-extraction solution is 35.17 g / L, corresponding to a vanadium recovery rate of 99.92%. The mass fraction of vanadate in the solid after evaporation, concentration and crystallization is 99.71%.

[0159] 8. Regeneration: The regenerant used in the regeneration section is pure water. Compared with O / A = 5 / 1, the regeneration stage is 1. The regenerated organic phase is recycled. There is no need to repeat the organic phase pretreatment. It can be directly returned to the organic phase inlet of the extraction section for recycling.

[0160] This embodiment discloses an application of effectively separating and extracting vanadium and molybdenum from a vanadium-molybdate solution, using the above-described method for effectively separating and extracting vanadium and molybdenum from a vanadium-molybdate solution.

[0161] This embodiment discloses a method for recovering molybdenum and vanadium from HDS waste catalyst. In addition to the above-mentioned method for effectively separating and extracting vanadium and molybdenum from vanadium molybdate solution, it also includes: using HDS waste catalyst leachate prepared by leaching HDS waste catalyst as vanadium molybdate solution.

[0162] This embodiment discloses a system for effectively separating and extracting vanadium and molybdenum from a vanadium-molybdate solution. The method for recovering molybdenum and vanadium from a vanadium-molybdate solution using this embodiment is as follows: Figure 2 As shown, the difference from Example 1 is:

[0163] The extraction unit includes four centrifugal extractors connected in series for multi-stage countercurrent extraction;

[0164] The anti-molybdenum unit consists of five centrifugal extractors connected in series for multi-stage countercurrent back-extraction.

[0165] The antivanadium unit includes four centrifugal extractors connected in series for multi-stage countercurrent back-extraction.

[0166] The regeneration unit also includes a centrifugal extractor connected in series for multi-stage countercurrent regeneration;

[0167] The washing unit contains four centrifugal extractors connected in series for multi-stage countercurrent washing.

[0168] The washing unit purifies the vanadium-molybdenum loading 1 and removes impurities from the organic phase; the purification unit includes four centrifugal extractors connected in series for multi-stage countercurrent purification.

[0169] Example 3

[0170] This embodiment discloses a method for recovering molybdenum and vanadium from a vanadium-molybdate solution, comprising:

[0171] 1. Vanadium-molybdate solution pretreatment: The vanadium-molybdate solution is obtained by acid leaching of HDS waste catalyst and conventional industrial impurity removal. The pH of the leachate is adjusted to 3.8 using alkaline solution. The Mo content in the leachate is 22.4 g / L and the V content is 14.8 g / L.

[0172] 2. Organic phase pretreatment: The organic phase is a mixture of 10% N2O8, 15% Adogen464, 15% n-heptanol and 60% 260# solvent oil by volume. The organic phase is treated 6 times with 1 mol / L sulfuric acid solution at a ratio O / A = 1 / 1, and then washed with deionized water until it is nearly neutral.

[0173] 3. Extraction: The pretreated organic phase was mixed with the pretreated leachate at a ratio of O / A = 3 / 1 for extraction. The extraction stage was 5 stages to obtain vanadium-molybdenum loaded 1 and raffinate, wherein the raffinate contained 18 ppm of vanadium and 23 ppm of molybdenum.

[0174] 4. Washing: The washing agent used is a dilute sulfuric acid solution with a pH of 4.1. The washing ratio O / A = 6 / 1, and the washing stage is 5 stages. Vanadium-molybdenum loaded 2 and wash water are obtained. The wash water is refluxed to the aqueous phase inlet of the extraction section and enters the extraction section together with the leachate after pretreatment.

[0175] 5. Molybdenum back-extraction: The reaction agent used for molybdenum back-extraction is a sodium sulfate solution with a pH of 8.8 and a sodium sulfate concentration of 0.2 mol / L. The ratio of O / A is 5 / 1, and the number of stages is 7. Vanadium-loaded solution 1 and molybdenum-rich back-extraction solution are obtained. The molybdenum concentration in the molybdenum-rich back-extraction solution is 37.3 g / L, corresponding to a molybdenum recovery rate of 99.90%. The mass fraction of molybdate in the solid after evaporation, concentration and crystallization is 99.63%.

[0176] 6. Purification: The purification agent used is a sodium sulfate solution with a pH of 9.7 and a sodium sulfate concentration of 0.05 mol / L. Compared with O / A = 6 / 1, the purification stage is 5 stages, resulting in vanadium-loaded 2 and purified liquid. After adjusting the pH, the purified liquid is returned to the water phase inlet of the washing section as a washing agent and is recycled.

[0177] 7. Vanadium back-extraction: The reaction agent used for vanadium back-extraction is a sodium sulfate solution with a pH of 13.5 and a sodium sulfate concentration of 0.1 mol / L. The ratio of O / A is 4 / 1, and the number of stages is 4. A blank organic phase and a vanadium-rich back-extraction solution are obtained. The vanadium concentration in the vanadium-rich back-extraction solution is 19.71 g / L, corresponding to a vanadium recovery rate of 99.88%. The mass fraction of vanadate in the solid after evaporation, concentration and crystallization is 99.64%.

[0178] 8. Regeneration: The regenerant used in the regeneration section is pure water. Compared with O / A = 7 / 1, the regeneration stage is 1. The regenerated organic phase is recycled. There is no need to repeat the organic phase pretreatment. It can be directly returned to the organic phase inlet of the extraction section for recycling.

[0179] This embodiment discloses an application of effectively separating and extracting vanadium and molybdenum from a vanadium-molybdate solution, using the above-described method for effectively separating and extracting vanadium and molybdenum from a vanadium-molybdate solution.

[0180] This embodiment discloses a method for recovering molybdenum and vanadium from HDS waste catalyst. In addition to the above-mentioned method for effectively separating and extracting vanadium and molybdenum from vanadium molybdate solution, it also includes: using HDS waste catalyst leachate prepared by leaching HDS waste catalyst as vanadium molybdate solution.

[0181] This embodiment discloses a system for effectively separating and extracting vanadium and molybdenum from a vanadium-molybdate solution. The method for recovering molybdenum and vanadium from a vanadium-molybdate solution using this embodiment is as follows: Figure 2 As shown, the difference from Example 1 is:

[0182] The extraction unit includes five centrifugal extractors connected in series for multi-stage countercurrent extraction;

[0183] The anti-molybdenum unit consists of seven centrifugal extractors connected in series for multi-stage countercurrent back-extraction.

[0184] The antivanadium unit includes four centrifugal extractors connected in series for multi-stage countercurrent back-extraction.

[0185] The regeneration unit also includes a centrifugal extractor connected in series for multi-stage countercurrent regeneration;

[0186] The washing unit contains five centrifugal extractors connected in series for multi-stage countercurrent washing.

[0187] The washing unit purifies the vanadium-molybdenum loading 1 and removes impurities from the organic phase; the purification unit includes five centrifugal extractors connected in series for multi-stage countercurrent purification.

[0188] Example 4

[0189] This embodiment discloses a method for recovering molybdenum and vanadium from a vanadium molybdate solution. The difference from Example 1 is that the organic phase is composed of 5% Hostarex A324, 20% TOMAC, 15% n-heptanol, and 60% 260# solvent oil by volume; the rest is the same as in Example 1.

[0190] The recovery rate of molybdenum was 99.75%, and the mass fraction of molybdate in the solid after evaporation, concentration, and crystallization was 99.68%; the recovery rate of vanadium was 99.82%, and the mass fraction of vanadate in the solid after evaporation, concentration, and crystallization was 99.63%.

[0191] This embodiment discloses an application of effectively separating and extracting vanadium and molybdenum from a vanadium-molybdate solution, using the above-described method for effectively separating and extracting vanadium and molybdenum from a vanadium-molybdate solution.

[0192] This embodiment discloses a method for recovering molybdenum and vanadium from HDS waste catalyst. In addition to the above-mentioned method for effectively separating and extracting vanadium and molybdenum from vanadium molybdate solution, it also includes: using HDS waste catalyst leachate prepared by leaching HDS waste catalyst as vanadium molybdate solution.

[0193] This embodiment discloses a system for effectively separating and extracting vanadium and molybdenum from a vanadium-molybdate solution. The method for recovering molybdenum and vanadium from a vanadium-molybdate solution using this embodiment is the same as the system for separating and extracting vanadium and molybdenum in Example 1.

[0194] Comparative Example 1

[0195] This comparative example discloses a method for recovering molybdenum and vanadium from a vanadium-molybdate solution. The difference from Example 1 is that the pH of the leaching solution required for co-extraction of vanadium and molybdenum is adjusted to 2. Under this condition, the extraction effect is basically unaffected, but acid consumption and cost are increased.

[0196] This comparative example discloses an application of effectively separating and extracting vanadium and molybdenum from a vanadium-molybdate solution, using the above-described method for effectively separating and extracting vanadium and molybdenum from a vanadium-molybdate solution.

[0197] This comparative example discloses a method for recovering molybdenum and vanadium from HDS waste catalyst. In addition to the above-mentioned method for effectively separating and extracting vanadium and molybdenum from vanadium molybdate solution, it also includes: using the HDS waste catalyst leachate prepared by leaching the HDS waste catalyst as a vanadium molybdate solution.

[0198] The system used in this comparative example for separating and extracting vanadium and molybdenum is the same as the system used in Example 1 for recovering molybdenum and vanadium from the vanadium-molybdate solution.

[0199] Comparative Example 2

[0200] This comparative example discloses a method for recovering molybdenum and vanadium from a vanadium-molybdate solution. The difference from Example 1 is that the pH of the leaching solution required for co-extraction of vanadium and molybdenum is adjusted to 5. Under this condition, the recovery rate of molybdenum will decrease to about 80%, while other results are basically unaffected.

[0201] This comparative example discloses an application of effectively separating and extracting vanadium and molybdenum from a vanadium-molybdate solution, using the above-described method for effectively separating and extracting vanadium and molybdenum from a vanadium-molybdate solution.

[0202] This comparative example discloses a method for recovering molybdenum and vanadium from HDS waste catalyst. In addition to the above-mentioned method for effectively separating and extracting vanadium and molybdenum from vanadium molybdate solution, it also includes: using the HDS waste catalyst leachate prepared by leaching the HDS waste catalyst as a vanadium molybdate solution.

[0203] The system used in this comparative example for separating and extracting vanadium and molybdenum is the same as the system used in Example 1 for recovering molybdenum and vanadium from the vanadium-molybdate solution.

[0204] Comparative Example 3

[0205] This comparative example discloses a method for recovering molybdenum and vanadium from a vanadium molybdate solution. The difference from Example 1 is that the pH of the detergent used in the washing section is adjusted to 6. Under this condition, the washing section will experience phase separation emulsification, making it impossible to carry out the experiment normally.

[0206] This comparative example discloses an application of effectively separating and extracting vanadium and molybdenum from a vanadium-molybdate solution, using the above-described method for effectively separating and extracting vanadium and molybdenum from a vanadium-molybdate solution.

[0207] This comparative example discloses a method for recovering molybdenum and vanadium from HDS waste catalyst. In addition to the above-mentioned method for effectively separating and extracting vanadium and molybdenum from vanadium molybdate solution, it also includes: using the HDS waste catalyst leachate prepared by leaching the HDS waste catalyst as a vanadium molybdate solution.

[0208] The system used in this comparative example for separating and extracting vanadium and molybdenum is the same as the system used in Example 1 for recovering molybdenum and vanadium from the vanadium-molybdate solution.

[0209] Comparative Example 4

[0210] This comparative example discloses a method for recovering molybdenum and vanadium from a vanadium-molybdate solution. The difference from Example 1 is that the pH of the purifying agent in the purification section is adjusted to 11. Under this condition, the recovery rate of vanadium will decrease to 85% to 90%, while other results are basically unaffected.

[0211] This comparative example discloses an application of effectively separating and extracting vanadium and molybdenum from a vanadium-molybdate solution, using the above-described method for effectively separating and extracting vanadium and molybdenum from a vanadium-molybdate solution.

[0212] This comparative example discloses a method for recovering molybdenum and vanadium from HDS waste catalyst. In addition to the above-mentioned method for effectively separating and extracting vanadium and molybdenum from vanadium molybdate solution, it also includes: using the HDS waste catalyst leachate prepared by leaching the HDS waste catalyst as a vanadium molybdate solution.

[0213] The system used in this comparative example for separating and extracting vanadium and molybdenum is the same as the system used in Example 1 for recovering molybdenum and vanadium from the vanadium-molybdate solution.

[0214] Comparative Example 5

[0215] This comparative example discloses a method for recovering molybdenum and vanadium from a vanadium-molybdate solution. The difference from Example 1 is that vanadium is reverse-extracted first, followed by molybdenum. Under these conditions, both molybdenum and vanadium are back-extracted during the vanadium-extraction process, making it impossible to separate and purify vanadium and molybdenum.

[0216] This comparative example discloses an application of effectively separating and extracting vanadium and molybdenum from a vanadium-molybdate solution, using the above-described method for effectively separating and extracting vanadium and molybdenum from a vanadium-molybdate solution.

[0217] This comparative example discloses a method for recovering molybdenum and vanadium from HDS waste catalyst. In addition to the above-mentioned method for effectively separating and extracting vanadium and molybdenum from vanadium molybdate solution, it also includes: using the HDS waste catalyst leachate prepared by leaching the HDS waste catalyst as a vanadium molybdate solution.

[0218] The system used in this comparative example for separating and extracting vanadium and molybdenum is the same as the system used in Example 1 for recovering molybdenum and vanadium from the vanadium-molybdate solution.

[0219] Comparative Example 6

[0220] This comparative example discloses a method for recovering molybdenum and vanadium from a vanadium molybdate solution. The difference from Example 1 is that a mixed extractant of a quaternary ammonium salt and a tertiary amine (R3N) extractant is used. The quaternary ammonium salt is the same as in Example 1, and the tertiary amine (R3N) is a tertiary amine extractant with a substituent C6 alkane group, and does not belong to one or more of the following: R=C8-C10 tertiary amines, R=isooctyl tertiary amines, and N2O8.

[0221] Under these conditions, the recovery rates of vanadium and molybdenum decrease to <80%, with vanadium recovery rate at 76% and molybdenum recovery rate at 74%.

[0222] This comparative example discloses an application of effectively separating and extracting vanadium and molybdenum from a vanadium-molybdate solution, using the above-described method for effectively separating and extracting vanadium and molybdenum from a vanadium-molybdate solution.

[0223] This comparative example discloses a method for recovering molybdenum and vanadium from HDS waste catalyst. In addition to the above-mentioned method for effectively separating and extracting vanadium and molybdenum from vanadium molybdate solution, it also includes: using the HDS waste catalyst leachate prepared by leaching the HDS waste catalyst as a vanadium molybdate solution.

[0224] The system used in this comparative example for separating and extracting vanadium and molybdenum is the same as the system used in Example 1 for recovering molybdenum and vanadium from the vanadium-molybdate solution.

[0225] Comparative Example 7

[0226] This comparative example discloses a method for recovering molybdenum and vanadium from a vanadium molybdate solution. The difference from Example 1 is that a mixed extractant of quaternary ammonium salt and tertiary amine (R3N) is used. The tertiary amine (R3N) is the same as in Example 1. The substituent of the quaternary ammonium salt is a C6 alkane group, which does not belong to N263, Aliquat336, TOMAC or Adogen464.

[0227] Under these conditions, the recovery rates of vanadium and molybdenum decrease to <40%, with vanadium recovery at 34% and molybdenum recovery at 38%.

[0228] This comparative example discloses an application of effectively separating and extracting vanadium and molybdenum from a vanadium-molybdate solution, using the above-described method for effectively separating and extracting vanadium and molybdenum from a vanadium-molybdate solution.

[0229] This comparative example discloses a method for recovering molybdenum and vanadium from HDS waste catalyst. In addition to the above-mentioned method for effectively separating and extracting vanadium and molybdenum from vanadium molybdate solution, it also includes: using the HDS waste catalyst leachate prepared by leaching the HDS waste catalyst as a vanadium molybdate solution.

[0230] The system used in this comparative example for separating and extracting vanadium and molybdenum is the same as the system used in Example 1 for recovering molybdenum and vanadium from the vanadium-molybdate solution.

[0231] As shown in Examples 1-4, the recovery rate of molybdenum is 99.75% to 99.90%, and the mass fraction of molybdate in the solid after evaporation, concentration, and crystallization is 99.58% to 99.68%; the recovery rate of vanadium is 99.82% to 99.92%, and the mass fraction of vanadate in the solid after evaporation, concentration, and crystallization is 99.59% to 99.71%.

[0232] Comparing Example 1, Comparative Example 1, and Comparative Example 2, it can be seen that the pH of the leachate required for the co-extraction of vanadium and molybdenum has a significant impact on the recovery rate of molybdenum. The optimal pH of the leachate required for the co-extraction of vanadium and molybdenum is 3 to 4.

[0233] Comparing Example 1, Comparative Example 3, and Comparative Example 4, it can be seen that pH in the washing and purification stages has a significant impact on the separation and vanadium recovery rate.

[0234] Comparing Example 1 and Comparative Example 5, it can be seen that only by back-extracting molybdenum first and then back-extracting vanadium can vanadium-molybdenum separation and purification be achieved; if vanadium is back-extracted first and then molybdenum is back-extracted, vanadium-molybdenum separation and purification cannot be achieved.

[0235] Comparing Example 1, Comparative Example 6, and Comparative Example 7, it can be seen that the type of extractant and the different substituents of the extractant have a significant impact on the recovery rate of vanadium and molybdenum. The recovery rate of vanadium and molybdenum is significantly reduced when the extractant does not meet the scope of the present invention.

[0236] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for effectively separating and extracting vanadium and molybdenum from a vanadium-molybdate solution, characterized in that, include: Based on pH adjustment in vanadium molybdate solution, co-extraction of vanadium and molybdenum elements in organic relative leachate is achieved; Based on pH adjustment in the back-extraction reagent, molybdenum and vanadium elements are sequentially back-extracted and recovered; The vanadium and molybdenum elements are extracted using organic phases with the same composition.

2. The method for effectively separating and extracting vanadium and molybdenum from a vanadium-molybdate solution according to claim 1, characterized in that, The method for effectively separating and extracting vanadium and molybdenum from a vanadium-molybdate solution includes: Vanadium and molybdenum co-extraction was achieved by extracting the organic phase under acidic conditions. Molybdenum is back-extracted under alkaline conditions to achieve separation of molybdenum from the vanadium-rich extract organic phase; Vanadium is back-extracted in a more alkaline environment, which separates vanadium from the extracted organic phase.

3. The method for effectively separating and extracting vanadium and molybdenum from a vanadium-molybdate solution according to claim 2, characterized in that, The method for effectively separating and extracting vanadium and molybdenum from a vanadium-molybdate solution includes: S1. Obtain a vanadium molybdate solution, adjust the vanadium molybdate solution to acidity, and use an extractive organic phase to extract the vanadium molybdate solution to achieve molybdenum-vanadium co-extraction and obtain a molybdenum-vanadium-rich extractive organic phase; S2. Add back-extraction reagent to back-extract molybdenum, adjust the back-extraction reagent to alkaline, and use the back-extraction reagent to back-extract the molybdenum-vanadium-rich organic phase to obtain a vanadium-rich organic phase and a molybdenum-rich back-extraction solution. S3. Add a back-extraction reagent to back-extract vanadium, adjust the back-extraction reagent to a stronger alkalinity than the back-extraction reagent in step S2, and back-extract the vanadium-rich organic compound to obtain a vanadium-rich back-extraction solution. S4. The vanadium-rich back-extraction solution and the molybdenum-rich back-extraction solution are processed independently to obtain vanadium and molybdenum products.

4. The method for effectively separating and extracting vanadium and molybdenum from a vanadium-molybdate solution according to claim 3, characterized in that, The pH value of the leachate required for the co-extraction of vanadium and molybdenum is 3 to 4.

5. The method for effectively separating and extracting vanadium and molybdenum from a vanadium-molybdate solution according to claim 3, characterized in that, The pH value of the back-extraction reagent required for molybdenum back-extraction is 8-9.

6. The method for effectively separating and extracting vanadium and molybdenum from a vanadium-molybdate solution according to claim 3, characterized in that, The pH value of the back-extraction reagent required for vanadium back-extraction is >12.

7. The method for effectively separating and extracting vanadium and molybdenum from a vanadium-molybdate solution according to any one of claims 3-6, characterized in that, Prior to S2, there is a step of washing and removing impurities from the molybdenum-vanadium-rich extract organic phase and mixing the refluxed wash water with a vanadium-molybdate solution adjusted to acidity as the aqueous phase feed into the extraction section.

8. An application for the efficient separation and extraction of vanadium and molybdenum from vanadium-molybdate solution, characterized in that, The method for effectively separating and extracting vanadium and molybdenum from a vanadium-molybdate solution according to any one of claims 1-7.

9. A method for recovering molybdenum and vanadium from spent HDS catalyst, characterized in that, In addition to the method for effectively separating and extracting vanadium and molybdenum from a vanadium-molybdate solution as described in any one of claims 1-7, the method further includes: using an HDS waste catalyst leachate prepared by leaching HDS waste catalyst as a vanadium-molybdate solution.

10. A system for recovering molybdenum and vanadium from spent HDS catalyst, characterized in that, The method for effectively separating and extracting vanadium and molybdenum from a vanadium-molybdate solution according to any one of claims 1-7, or the method for recovering molybdenum and vanadium from HDS waste catalyst according to claim 9, comprises: a pretreatment subsystem, an extraction unit, a reverse molybdenum unit, a reverse vanadium unit, and a regeneration unit connected sequentially from upstream to downstream of the material feed direction, wherein the outlet of the upstream unit is connected to the inlet of the adjacent downstream unit.

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