A method for cleaning and separating and recovering molybdenum and vanadium from HDS spent catalyst leaching solution

Abstract

This invention belongs to the field of spent catalyst recycling technology, and relates to a method for the clean separation and recovery of molybdenum and vanadium from HDS spent catalyst leachate. The method includes: adjusting the pH value of the leachate to achieve sequential extraction and recovery of vanadium and molybdenum from the leachate using an extractant organic phase, wherein the composition of the extractant organic phase used for vanadium and molybdenum extraction is identical. 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, it 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 spent catalyst recycling technology, and in particular to a method for the clean separation and recovery of molybdenum and vanadium from HDS spent catalyst leachate. Background Technology

[0002] HDS hydrodesulfurization catalysts, widely used industrial catalysts, are mainly composed of active components (primarily Mo, Co, Ni, V, Pt, and Pd and their compounds) and an alumina support. HDS catalysts suffer from the following problems: Firstly, during long-term use, the active components of the catalyst may be affected by factors such as heavy metals and nitrogen compounds, leading to reduced activity or even deactivation. Secondly, prolonged exposure to high temperatures and steam environments can also cause a decrease in the activity and a reduction in the lifespan of the HDS catalyst.

[0003] Current technologies for metal recovery from spent HDS catalysts primarily employ acid leaching, alkaline leaching, and roasting-leaching methods to prepare extraction leachates containing molybdenum and vanadium. Molybdenum and vanadium are then separated using precipitation, ion exchange resin, or solvent extraction methods. Precipitation methods are often used for preliminary separation of molybdenum and vanadium due to the high vanadium impurity content in the molybdenum precipitate and the low purity of the molybdenum and vanadium products. Ion exchange resin methods offer high selectivity, but require large amounts of acid and alkali during operation, generating significant amounts of strongly acidic and alkaline wastewater. Existing solvent extraction methods use a single extraction system to extract and recover molybdenum, but often struggle to extract and separate elements like vanadium, resulting in a waste of precious metal resources.

[0004] There is an urgent need in the existing technology for a method that can recover molybdenum, vanadium and other elements from HDS hydrodesulfurization catalysts separately, while ensuring high yield and product purity for each element. Summary of the Invention

[0005] Based on the above analysis, the present invention aims to provide a method for the clean separation and recovery of molybdenum and vanadium from HDS waste catalyst leachate, in order to solve at least one of the problems in the prior art, such as difficulty in achieving simultaneous recovery of 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 the clean separation and recovery of molybdenum and vanadium from HDS spent catalyst leachate includes: adjusting the pH value of the leachate to achieve sequential extraction and recovery of vanadium and molybdenum elements from the leachate using an extractant organic phase, wherein the composition of the extractant organic phase used for the extraction of vanadium and molybdenum elements is the same.

[0008] Preferably, the extractable organic phase comprises a quaternary ammonium salt extractant or a mixture of a quaternary ammonium salt extractant and a tertiary amine extractant.

[0009] 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.

[0010] Preferably, the tertiary amine with substituents of C8 to C10 is any one of N235, Alamine336, Adogen364, HostarexA327, and TOA.

[0011] Preferably, the tertiary amine with isooctyl substituent is any one of Adogen381, Alamine308, HostarexA324, and Adogen382.

[0012] Preferably, the quaternary ammonium salt extractant is one or more of N263, Aliquat336, TOMAC and Adogen464.

[0013] Preferably, the method for cleaning, separating, and recovering molybdenum and vanadium from the leachate includes:

[0014] S1. Adjust the HDS waste catalyst leachate to alkaline, and use the extraction organic phase to extract the HDS waste catalyst leachate to obtain vanadium-rich organic phase and molybdenum-rich raffinate.

[0015] S2. Adjust the molybdenum-rich raffinate to acidity, and use an extractive organic phase to extract the molybdenum-rich raffinate to obtain a molybdenum-rich organic phase and raffinate.

[0016] S3. The vanadium-rich organic phase and the molybdenum-rich organic phase are back-extracted independently to obtain vanadium-rich back-extracting solution and molybdenum-rich back-extracting solution;

[0017] S4. The vanadium-rich back-extraction solution and the molybdenum-rich back-extraction solution are processed independently to obtain vanadium and molybdenum products.

[0018] Preferably, the pH value of the leaching solution required for vanadium extraction is 8 to 9.

[0019] Preferably, the pH of the molybdenum-rich raffinate required for molybdenum extraction is 3 to 4.

[0020] Preferably, before step S3, there are steps of washing the vanadium-rich organic phase and recirculating the washing liquid to the vanadium extraction section as feed, and washing the molybdenum-rich organic phase and recirculating the washing liquid to the molybdenum extraction section as feed.

[0021] Preferably, the pH value of the detergent in the vanadium-rich organic phase is ≥ the pH value of the HDS waste catalyst leachate in S1 after pH adjustment.

[0022] Preferably, the pH value of the detergent in the molybdenum-rich organic phase is ≥ the pH value of the molybdenum-rich raffinate in S2 after pH adjustment.

[0023] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0024] (1) This invention achieves selective alteration of vanadium and molybdenum elements in the same extractable organic by adjusting the pH value in the leachate. While ensuring the extraction and separation effect, it achieves sequential extraction and recovery of vanadium and molybdenum elements in the leachate. This overcomes the defects of low yield and low product purity caused by poor separation effect of each element in the leachate in the existing technology. It achieves a vanadium recovery rate of ≥99%, and a vanadate mass fraction of ≥99.5% in the solid after evaporation, concentration and crystallization; a molybdenum recovery rate of ≥99%, and a molybdate mass fraction of ≥99.5% in the solid after evaporation, concentration and crystallization.

[0025] (2) The present invention uses the raffinate to prepare HDS waste catalyst leachate. 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 various precious metal elements during the raffinate reflux process, which facilitates the recovery of precious metal elements; at the same time, it reduces waste liquid discharge, reduces environmental pollution and costs.

[0026] (3) 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 raffinate after back-extraction can be recycled and reused without worrying about mutual contamination of the extraction systems, thus reducing waste discharge and environmental pollution.

[0027] (4) By controlling the pH value during washing the extraction phase, the present invention removes impurities while reducing the elution of molybdenum and vanadium during washing, thereby increasing the yield of both elements.

[0028] 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

[0029] 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.

[0030] Figure 1 This is a process flow diagram of the method for cleanly separating and recovering molybdenum and vanadium from HDS waste catalyst leachate according to the present invention. Detailed Implementation

[0031] 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.

[0032] On one hand, this invention discloses a method for the clean separation and recovery of molybdenum and vanadium from HDS spent catalyst leachate, comprising:

[0033] The extraction organic phase is based on pH adjustment in the leachate to achieve sequential extraction and recovery of vanadium and molybdenum elements in the leachate. The composition of the extraction organic phase is the same for the extraction of vanadium and molybdenum elements.

[0034] In practice, this invention preferentially extracts vanadium under alkaline conditions to separate vanadium from molybdenum-rich raffinate and enrich vanadium; further, it extracts molybdenum under acidic conditions to separate molybdenum from raffinate and enrich molybdenum.

[0035] Compared with existing technologies, this invention achieves selective changes in vanadium and molybdenum elements in the same extractable organic compound by adjusting the pH value in the leachate. While ensuring the extraction and separation effect, it realizes the sequential extraction and recovery of vanadium and molybdenum elements in the leachate. At the same time, it overcomes the defects of existing technologies, such as low yield and low product purity caused by poor separation effect of each element in the leachate.

[0036] It should be noted that this invention achieves 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 elements are extracted using different extraction systems; at the same time, since the extraction organic phase is the same, the raffinate after back-extraction can be recycled without worrying about cross-contamination between extraction systems, thus reducing waste liquid discharge and environmental pollution.

[0037] Specifically, the extractable organic phase includes quaternary ammonium salt extractants or a mixture of quaternary ammonium salt extractants and tertiary amine extractants.

[0038] 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.

[0039] Preferably, the tertiary amine with substituents of C8 to C10 is any one of N235, Alamine336, Adogen364, HostarexA327, and TOA.

[0040] Preferably, the tertiary amine with isooctyl substituent is any one of Adogen381, Alamine308, HostarexA324, and Adogen382.

[0041] Preferably, the pH value of the leachate required for vanadium extraction is 8-9; the pH value of the molybdenum-rich raffinate required for molybdenum extraction is 3-4.

[0042] It should be noted that when the pH value is between 2 and 9, vanadium in the leaching solution exists in the forms of V4O

[0044] ,

[0047] ,

[0046] ,

[0045] , , , , 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 existence forms. When the pH value is < 2 and the pH value is > 10, the extraction rate of vanadium by the extraction organic phase drops significantly.

[0043] It should be noted that when the pH value is < 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 [[ID=�9]] 3- ), Mo8O 26 4- and in the form of cationic polymers under strong acidic conditions. The extraction organic phase has extremely high extraction selectivity for its various polymeric polyacid anions. When 4 < pH < 8, the extraction rate of molybdenum by the extraction organic phase gradually decreases. When pH > 8, the extraction rate of molybdenum by the extraction organic phase drops significantly.

[0044] Meanwhile, it should be noted that when extracting vanadium and molybdenum elements sequentially as described above, the extraction order of vanadium and molybdenum elements cannot be adjusted. For example, if processed sequentially in the manner of "first extracting molybdenum and then extracting vanadium" according to the aforementioned method, the separation effect of molybdenum and vanadium will be deteriorated, resulting in more vanadium impurities in the molybdenum product and reducing the purity of the molybdenum product.

[0045] Preferably, the extraction organic phase further includes an alcohol phase regulator with 7 to 10 carbon atoms in the molecule.

[0046] Specifically, the alcohol phase regulator can be one or more of n-heptanol, n-octanol, sec-octanol, isooctanol, n-decanol, etc.

[0047] 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.

[0048] 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.

[0049] 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.

[0050] Preferably, the diluent can be 260# solvent oil.

[0051] 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%.

[0052] 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%.

[0053] 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%.

[0054] 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%.

[0055] Specifically, the method for cleaning, separating, and recovering molybdenum and vanadium from the leachate includes:

[0056] S1. Adjust the HDS waste catalyst leachate to alkaline, and use the extraction organic phase to extract the HDS waste catalyst leachate to obtain vanadium-rich organic phase and molybdenum-rich raffinate.

[0057] S2. Adjust the molybdenum-rich raffinate to acidity, and use an extractive organic phase to extract the molybdenum-rich raffinate to obtain a molybdenum-rich organic phase and raffinate.

[0058] S3. The vanadium-rich organic phase and the molybdenum-rich organic phase are back-extracted independently to obtain vanadium-rich back-extracting solution and molybdenum-rich back-extracting solution;

[0059] S4. The vanadium-rich back-extraction solution and the molybdenum-rich back-extraction solution are processed independently to obtain vanadium and molybdenum products.

[0060] Specifically, in S1, the pH value of the HDS waste catalyst leachate is adjusted to 8-9.

[0061] Specifically, the extraction ratio in S1 is O / A = 1:5 to 5:1, and the number of extraction stages is 2 to 10.

[0062] Specifically, in S2, the pH of the molybdenum-rich raffinate is adjusted to 3-4.

[0063] Specifically, the extraction ratio in S2 is O / A = 1:5 to 5:1, and the number of extraction stages is 2 to 8.

[0064] Specifically, the ratio of vanadium-rich organic back-extraction in S3 is O / A = 1 to 10:1, and the number of back-extraction stages is 2 to 10.

[0065] Specifically, the ratio of back-extraction in molybdenum-rich organic compounds in S3 is O / A = 1 to 10:1, and the number of back-extraction stages is 2 to 10.

[0066] Preferably, before step S3, there are steps of washing the vanadium-rich organic phase and refluxing the washing liquid to the vanadium extraction section, and washing the molybdenum-rich organic phase and refluxing the washing liquid to the molybdenum extraction section.

[0067] Specifically, the vanadium-rich organic phase and molybdenum-rich organic phase detergents are sulfate aqueous solutions.

[0068] Specifically, the washing ratio of vanadium-rich organic phase and molybdenum-rich organic phase is 5 to 10:1.

[0069] Specifically, the pH value of the vanadium-rich organic phase detergent is ≥ the pH value of the HDS waste catalyst leachate in S1 after adjustment.

[0070] Preferably, the pH value of the vanadium-rich organic phase detergent can be selected as 8 to 9.5.

[0071] It should be noted that within this pH range, while ensuring a relatively low vanadium elution efficiency, other impurities 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 < 8, incomplete molybdenum elution may occur in the vanadium-rich organic phase, leading to a decrease in the purity of the vanadium-rich back-extraction solution; when pH > 9.5, vanadium in the vanadium-rich organic phase will have a high elution rate, resulting in a decrease in vanadium yield.

[0072] Specifically, the sulfate concentration of the vanadium-rich organic phase detergent is 0.05 mol / L to 0.5 mol / L.

[0073] Specifically, the pH value of the molybdenum-rich organic phase detergent is ≥ the pH value of the molybdenum-rich raffinate in S2 after adjustment.

[0074] Preferably, the pH value of the molybdenum-rich organic phase detergent can be selected as 3 to 5.

[0075] It should be noted that within this pH range, while ensuring a relatively low elution efficiency for molybdenum, it effectively removes other impurities entrained in the molybdenum-rich organic phase, which is beneficial for enriching and purifying the downstream molybdenum-rich back-extraction solution. When pH < 3, more acid will be consumed, increasing costs; when pH > 5, molybdenum in the molybdenum-rich organic phase will have a high elution rate, leading to a decrease in molybdenum yield.

[0076] Specifically, the sulfate concentration of the molybdenum-rich organic phase detergent is 0.05 mol / L to 0.5 mol / L.

[0077] Preferably, the method for cleaning, separating, and recovering molybdenum and vanadium from the leachate further includes:

[0078] The blank organic phase obtained from S3 back-extraction was washed and regenerated with water and used as the reflux for extraction organic phase.

[0079] Specifically, the ratio of O / A to O / A in the blank organic phase water washing regeneration is 1 to 10:1, and the number of stages is 1 to 2.

[0080] Preferably, S1 further includes:

[0081] S0. The organic phase of the extract is treated with acid to remove inorganic impurities and obtain activated quaternary ammonium salt.

[0082] Specifically, S0 includes:

[0083] S001. Mix the extractant, phase modifier, and diluent evenly according to the set volume ratio to obtain the extractable organic phase;

[0084] S002. The extracted organic phase obtained in S001 is washed with a sulfuric acid solution of 1 mol / L to 2 mol / L.

[0085] S003. Further wash the extracted organic phase treated with S002 until it is neutral.

[0086] Preferably, the method for cleaning, separating, and recovering molybdenum and vanadium from the leachate further includes:

[0087] S5. The raffinate is recycled to prepare HDS waste catalyst leachate, recovering unextracted vanadium and molybdenum, and concentrating the remaining precious metals except vanadium and molybdenum.

[0088] 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.

[0089] Compared with existing technologies, this invention uses the raffinate to prepare HDS waste catalyst leachate, which on the one hand avoids the waste of vanadium and molybdenum elements and improves the yield of vanadium and molybdenum elements; on the other hand, the raffinate reflux process achieves the enrichment of various precious metal elements, which facilitates the recovery of precious metal elements.

[0090] To better illustrate the present invention, the following embodiments and comparative examples are provided:

[0091] Example 1

[0092] This embodiment discloses a method for the clean separation and recovery of molybdenum and vanadium from HDS spent catalyst leachate, such as... Figure 1 As shown, it includes:

[0093] 1. Leachate pretreatment: The leachate is the solution obtained after alkaline leaching of HDS waste catalyst. The pH of the leachate is adjusted to 8.8 using concentrated sulfuric acid. The Mo content in the leachate is 23.4 g / L and the V content is 13.8 g / L.

[0094] 2. Organic phase pretreatment: The organic phase is a mixture of 10% Alamine 336, 15% 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.

[0095] 3. Vanadium extraction: The pretreated organic phase was mixed with the pretreated leachate at a ratio of O / A = 1 / 1.5 for extraction. The extraction stage was 5 stages to obtain vanadium-loaded 1 and molybdenum-rich raffinate, wherein the vanadium content in the molybdenum-rich raffinate was 16 ppm.

[0096] 4. Washing 1: The detergent used in washing 1 is a sodium sulfate solution with a pH of 9 and a sodium sulfate concentration of 0.3 mol / L. The ratio of O / A in washing 1 is 8 / 1, and the number of washing stages in washing 1 is 8, resulting in vanadium-containing load 2 and wash water 1. Wash water 1 is used as the feed water for vanadium extraction.

[0097] 5. Back-extraction 1: The reaction agent used in back-extraction 1 is alkaline sodium sulfate, in which OH... -The concentration was 0.16 mol / L, the sodium sulfate concentration was 0.25 mol / L, the O / A ratio of back-extraction 1 was 1 / 1, the number of back-extraction stages was 6, and a blank organic phase and a vanadium-rich back-extraction solution were obtained. The vanadium concentration in the vanadium-rich back-extraction solution was 20.68 g / L, corresponding to a vanadium recovery rate of 99.88%. The mass fraction of vanadate in the solid after evaporation, concentration and crystallization was 99.68%.

[0098] 6. Regeneration 1: Regeneration 1 uses pure water. Compared with O / A = 6 / 1, Regeneration 1 is a single stage. The pH of the effluent from Regeneration 1 is controlled at near neutral. The regenerated organic phase is obtained. There is no need to repeat the organic phase pretreatment. It can be directly returned to the extraction system for recycling.

[0099] 7. Molybdenum extraction: The pH of the molybdenum-rich raffinate was adjusted to 3.8 using sulfuric acid. The pretreated organic phase was mixed with the pH-adjusted molybdenum-rich raffinate at a ratio of O / A = 1.5 / 1 for extraction. The extraction stage was 4 stages, resulting in molybdenum-loaded 1 and raffinate. The molybdenum content in the raffinate was 22 ppm, and the raffinate was returned to the front end for leaching.

[0100] 8. Washing 2: The detergent used in washing 2 is a sodium sulfate solution with a pH of 4 and a sodium sulfate concentration of 0.15 mol / L. The ratio of O / A in washing 2 is 7 / 1, and the number of washing stages in washing 2 is 5, resulting in molybdenum-loaded 2 and wash water 2. Wash water 2 is used as the feed water for molybdenum extraction.

[0101] 9. Back-extraction 2: The reaction agent used in back-extraction 2 is an alkaline sodium sulfate solution, in which OH... - The concentration was 0.41 mol / L, the sodium sulfate concentration was 0.25 mol / L, the O / A ratio of the back-extraction phase 2 was 4 / 1, the back-extraction phase 2 had 6 stages, and a blank organic phase and a molybdenum-rich back-extraction solution were obtained. The Mo concentration in the molybdenum-rich back-extraction solution was 62.34 g / L, corresponding to a molybdenum recovery rate of 99.91%. The mass fraction of molybdate in the solid after evaporation, concentration and crystallization was 99.70%.

[0102] 10. Regeneration 2: Regeneration 2 uses pure water. Compared to O / A = 6 / 1, Regeneration 2 is a single stage. The pH of the effluent from Regeneration 2 is controlled at near neutral. The regenerated organic phase is obtained and does not require repeated organic phase pretreatment. It can be directly returned to the extraction system for recycling.

[0103] Example 2

[0104] This embodiment discloses a method for the clean separation and recovery of molybdenum and vanadium from HDS spent catalyst leachate, such as... Figure 1 As shown, it includes:

[0105] 1. Leachate pretreatment: The leachate is the solution obtained after acid leaching of HDS waste catalyst. The pH of the leachate is adjusted to 8.2 using liquid alkali. The Mo content in the leachate is 8.26 g / L and the V content is 6.79 g / L.

[0106] 2. Organic phase pretreatment: The organic phase is a mixture of 5% Alamine 308, 15% Aliquat 336, 10% n-decyl alcohol and 70% 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.

[0107] 3. Vanadium extraction: The pretreated organic phase was mixed with the pretreated leachate at a ratio of O / A = 1 / 3 for extraction. The extraction stage was 7 stages to obtain vanadium-loaded 1 and molybdenum-rich raffinate, wherein the vanadium content in the molybdenum-rich raffinate was 9 ppm.

[0108] 4. Washing 1: The detergent used in washing 1 is a potassium sulfate solution with a pH of 8.7 and a potassium sulfate concentration of 0.1 mol / L. The ratio of O / A in washing 1 is 6 / 1, and the number of washing stages is 6. The vanadium-containing load 2 and the wash water 1 are obtained. The wash water 1 is used as the feed water for vanadium extraction.

[0109] 5. Back-extraction 1: The reaction agent used in back-extraction 1 is an alkaline potassium sulfate solution, in which the OH- concentration is 0.41 mol / L and the potassium sulfate concentration is 0.2 mol / L. The O / A ratio of back-extraction 1 is 1.5 / 1, and the number of back-extraction stages is 5. A blank organic phase and a vanadium-rich back-extraction solution are obtained. The V concentration in the vanadium-rich back-extraction solution is 30.51 g / L, corresponding to a vanadium recovery rate of 99.87%. The vanadate mass fraction in the solid after evaporation, concentration and crystallization is 99.50%.

[0110] 6. Regeneration 1: Regeneration 1 uses pure water. Compared with O / A = 5 / 1, Regeneration 1 has 2 stages. The pH of the effluent from Regeneration 1 is controlled at near neutral. The regenerated organic phase is obtained. There is no need to repeat the organic phase pretreatment. It can be directly returned to the extraction system for recycling.

[0111] 7. Molybdenum extraction: The pH of the molybdenum-rich raffinate was adjusted to 3.2 using sulfuric acid. The pretreated organic phase was mixed with the pH-adjusted molybdenum-rich raffinate at a ratio of O / A = 1 / 2 for extraction. The extraction was performed in 5 stages to obtain molybdenum-loaded 1 and raffinate. The molybdenum content in the raffinate was 14 ppm. The raffinate was returned to the front end for leaching.

[0112] 8. Washing 2: The detergent used in washing 2 is a potassium sulfate solution with a pH of 3.7 and a potassium sulfate concentration of 0.08 mol / L. The ratio of O / A in washing 2 is 6 / 1. The washing 2 has 3 stages, resulting in molybdenum-loaded 2 and wash water 2. Wash water 2 is used as the feed water for molybdenum extraction.

[0113] 9. Back-extraction 2: The reaction agent used in back-extraction 2 is an alkaline potassium sulfate solution, in which the OH- concentration is 0.67 mol / L and the potassium sulfate concentration is 0.2 mol / L. The O / A ratio of back-extraction 2 is 5 / 1, and the number of back-extraction stages is 5. A blank organic phase and a molybdenum-rich back-extraction solution are obtained. The Mo concentration in the molybdenum-rich back-extraction solution is 82.46 g / L, corresponding to a molybdenum recovery rate of 99.83%. The mass fraction of molybdate in the solid after evaporation, concentration and crystallization is 99.75%.

[0114] 10. Regeneration 2: Regeneration 2 uses pure water. Compared to O / A = 5 / 1, Regeneration 2 has 2 stages. The pH of the effluent from Regeneration 2 is controlled at near neutral. The regenerated organic phase is obtained. There is no need to repeat the organic phase pretreatment. It can be directly returned to the extraction system for recycling.

[0115] Example 3

[0116] This embodiment discloses a method for the clean separation and recovery of molybdenum and vanadium from HDS spent catalyst leachate, including:

[0117] 1. Leachate pretreatment: The leachate is the solution obtained after calcination-water leaching of HDS waste catalyst. A small amount of sulfuric acid is used to adjust the pH range of the leachate to 8.5. The Mo content in the leachate is 14.32 g / L and the V content is 21.09 g / L.

[0118] 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.

[0119] 3. Vanadium extraction: The pretreated organic phase was mixed with the pretreated leachate at a ratio of O / A = 1.1 / 1 for extraction. The extraction stage was 8 stages, resulting in vanadium-loaded 1 and molybdenum-rich raffinate, wherein the vanadium content in the molybdenum-rich raffinate was 11 ppm.

[0120] 4. Washing 1: The detergent used in washing 1 is a sodium sulfate solution with a pH of 9.5 and a sodium sulfate concentration of 0.2 mol / L. The ratio of O / A in washing 1 is 5 / 1, and the number of washing stages in washing 1 is 5, resulting in vanadium-containing load 2 and wash water 1. Wash water 1 is used as the feed water for vanadium extraction.

[0121] 5. Back-extraction 1: The reaction agent used in back-extraction 1 is an alkaline sodium sulfate solution with an OH- concentration of 0.89 mol / L and a sodium sulfate concentration of 0.25 mol / L. The O / A ratio of back-extraction 1 is 3 / 1, and the number of back-extraction stages is 5. A blank organic phase and a vanadium-rich back-extraction solution are obtained. The V concentration in the vanadium-rich back-extraction solution is 57.49 g / L, corresponding to a vanadium recovery rate of 99.95%. The vanadate mass fraction in the solid after evaporation, concentration, and crystallization is 99.71%.

[0122] 6. Regeneration 1: Regeneration 1 uses pure water. Compared with O / A = 7 / 1, Regeneration 1 is a single stage. The pH of the effluent from Regeneration 1 is controlled at near neutral. The regenerated organic phase is obtained. There is no need to repeat the organic phase pretreatment. It can be directly returned to the extraction system for recycling.

[0123] 7. Molybdenum extraction: The pH of the molybdenum-rich raffinate was adjusted to 3.5 using sulfuric acid. The pretreated organic phase was mixed with the pH-adjusted molybdenum-rich raffinate at a ratio of O / A = 1 / 1 for extraction. The extraction stage was 6 stages, resulting in a molybdenum-loaded 1 and raffinate. The raffinate contained 17 ppm of molybdenum and was returned to the front end for leaching.

[0124] 8. Washing 2: The detergent used in washing 2 is a sodium sulfate solution with a pH of 4.5 and a sodium sulfate concentration of 0.13 mol / L. The ratio of O / A in washing 2 is 8 / 1, and the number of washing stages in washing 2 is 5, resulting in molybdenum-loaded 2 and wash water 2. Wash water 2 is used as the feed water for molybdenum extraction.

[0125] 9. Back-extraction 2: The reaction agent used in back-extraction 2 is an alkaline sodium sulfate solution with an OH- concentration of 0.51 mol / L and a sodium sulfate concentration of 0.25 mol / L. The O / A ratio of back-extraction 2 is 5 / 1, and the number of stages in back-extraction 2 is 4. A blank organic phase and a molybdenum-rich back-extraction solution are obtained. The Mo concentration in the molybdenum-rich back-extraction solution is 71.52 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 99.61%.

[0126] 10. Regeneration 2: Regeneration 2 uses pure water. Compared to O / A = 7 / 1, Regeneration 2 is a single stage. The pH of the effluent from Regeneration 2 is controlled at near neutral. The regenerated organic phase is obtained. There is no need to repeat the organic phase pretreatment. It can be directly returned to the extraction system for recycling.

[0127] Example 4

[0128] This comparative example discloses a method for the clean separation and recovery of molybdenum and vanadium from HDS spent catalyst leachate. The difference between this method and Example 2 is that the organic phase is a mixture of 10% Hostarex A324, 15% TOMAC, 15% n-heptanol, and 60% 260# solvent oil by volume; the rest is the same as in Example 2.

[0129] The recovery rate of vanadium was 99.89%, and the mass fraction of vanadate in the solid after evaporation, concentration and crystallization was 99.50%; the recovery rate of molybdenum was 99.63%, and the mass fraction of molybdate in the solid after evaporation, concentration and crystallization was 99.55%.

[0130] Comparative Example 1

[0131] This comparative example discloses a method for the clean separation and recovery of molybdenum and vanadium from HDS waste catalyst leachate. The difference from Example 1 is that the pH of the leachate is adjusted to 10 before vanadium extraction, and the pH of the molybdenum-rich raffinate is adjusted to the same level as in Example 1 before molybdenum extraction.

[0132] The vanadium content in the obtained molybdenum-rich raffinate was 8.97 g / L;

[0133] The vanadium content in the obtained vanadium-rich back-extraction solution was 7.23 g / L, corresponding to a vanadium recovery rate of 35%.

[0134] The obtained raffinate contained 12.8 g / L of molybdenum and 3.34 g / L of vanadium.

[0135] The obtained molybdenum-rich back-extraction solution contained 15.01 g / L of vanadium and 28.27 g / L of molybdenum, with a molybdenum recovery rate of 45.30%. The solid after evaporation, concentration, and crystallization contained 61.26% molybdate by mass.

[0136] Comparative Example 2

[0137] This comparative example discloses a method for the clean separation and recovery of molybdenum and vanadium from HDS waste catalyst leachate. The difference from Example 1 is that the pH of the leachate is adjusted to 5 before vanadium extraction, and the pH of the molybdenum-rich raffinate is adjusted to the same level as in Example 1 before molybdenum extraction.

[0138] The obtained molybdenum-rich raffinate contained 5.91 g / L of vanadium and 18.4 g / L of molybdenum.

[0139] The obtained vanadium-rich back-extraction solution contained 3.33 g / L of molybdenum and 11.84 g / L of vanadium, corresponding to a vanadium recovery rate of 57.17%. The vanadate mass fraction in the solid after evaporation, concentration, and crystallization was 68.77%.

[0140] The obtained raffinate contained 8.91 g / L of molybdenum and 5 ppm of vanadium.

[0141] The obtained molybdenum-rich back-extraction solution contained 15.75 g / L of vanadium and 25.31 g / L of molybdenum, with a molybdenum recovery rate of 40.56%. The solid after evaporation, concentration, and crystallization contained 57.12% molybdate by mass.

[0142] Comparative Example 3

[0143] This comparative example discloses a method for the clean separation and recovery of molybdenum and vanadium from HDS waste catalyst leachate. The difference from Example 1 is that the pH adjustment of the leachate before vanadium extraction is the same as in Example 1, while the pH of the molybdenum-rich raffinate is adjusted to 2 before molybdenum extraction. Under these conditions, the acid consumption and cost are increased.

[0144] Comparative Example 4

[0145] This comparative example discloses a method for the clean separation and recovery of molybdenum and vanadium from HDS waste catalyst leachate. The difference from Example 3 is that the pH value of the sodium sulfate solution in the detergent used in Example 1 is adjusted to 7, while the other treatment processes are exactly the same as in Example 3.

[0146] The vanadium content in the obtained molybdenum-rich raffinate was 10 ppm;

[0147] The obtained vanadium-rich back-extraction solution contained 5.8 g / L of molybdenum and 54.41 g / L of vanadium, with a corresponding vanadium recovery rate of 94.60%. The vanadate mass fraction in the solid after evaporation, concentration, and crystallization was 90.98%.

[0148] The obtained raffinate contained 10 ppm of molybdenum and 2 ppm of vanadium.

[0149] The molybdenum content in the obtained molybdenum-rich back-extraction solution was 57.05 g / L, corresponding to a molybdenum recovery rate of 79.68%. The mass fraction of molybdate in the solid after evaporation, concentration, and crystallization was 94.87%.

[0150] Comparative Example 5

[0151] This comparative example discloses a method for the clean separation and recovery of molybdenum and vanadium from HDS waste catalyst leachate. The difference from Example 3 is that the pH value of the sodium sulfate solution in the washing agent used in washing 2 is adjusted to 2, while the other treatment processes are exactly the same as in Example 3. Under these conditions, the acid consumption is increased, and the cost is increased.

[0152] Comparative Example 6

[0153] This comparative example discloses a method for the clean separation and recovery of molybdenum and vanadium from HDS waste catalyst leachate. The difference from Example 3 is that molybdenum is extracted first, and the molybdenum extraction raffinate is used for vanadium extraction.

[0154] Molybdenum extraction: The pH of the leachate was adjusted to 3.5. The pretreated organic phase was mixed with the pH-adjusted leachate at a ratio of O / A = 1 / 1 for extraction. The extraction stage was 6 stages, resulting in molybdenum-loaded 1 and vanadium-rich raffinate. The vanadium-rich raffinate contained 7.52 g / L of molybdenum and 10.01 g / L of vanadium. The molybdenum-loaded 1 was then treated according to the steps in Example 3 to obtain the molybdenum product.

[0155] Vanadium extraction: Adjust the pH of the vanadium-rich raffinate to 8.5, and use the pretreated organic phase with a ratio O / A = 1.1 / 1 to mix and extract with the pH-adjusted vanadium-rich raffinate. The extraction stage is 8 stages to obtain vanadium-containing load 1 and raffinate. The vanadium-containing load 1 is treated according to the steps of Example 3 to obtain vanadium product.

[0156] The remaining extraction steps for molybdenum and vanadium, as well as the reflux of the raffinate, were adapted according to the principles set in Example 3.

[0157] The vanadium recovery rate was 47.46%, and the mass fraction of vanadate in the solid after evaporation, concentration, and crystallization was 72.95%.

[0158] The molybdenum recovery rate was 47.49%, and the mass fraction of molybdate in the solid after evaporation, concentration, and crystallization was 24.34%.

[0159] Comparative Example 7

[0160] This comparative example discloses a method for the clean separation and recovery of molybdenum and vanadium from HDS waste catalyst leachate. The difference from Example 1 is that a mixed extractant of quaternary ammonium salt and tertiary amine (R3N) extractant is used. The quaternary ammonium salt is the same as in Example 1. 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 amine, R=isooctyl tertiary amine, and N2O8.

[0161] The vanadium content in the obtained molybdenum-rich raffinate was 4.4 g / L;

[0162] The vanadium content in the obtained vanadium-rich back-extraction solution was 14.1 g / L, corresponding to a vanadium recovery rate of 68.12%. The mass fraction of vanadate in the solid after evaporation, concentration, and crystallization was 86.38%.

[0163] The obtained raffinate contained 12.18 g / L of molybdenum and 1.41 g / L of vanadium.

[0164] The obtained molybdenum-rich back-extraction solution contained 7.97 g / L of vanadium and 29.92 g / L of molybdenum, corresponding to a molybdenum recovery rate of 47.95%. The solid after evaporation, concentration, and crystallization contained 70.59% molybdate by mass.

[0165] Comparative Example 8

[0166] This comparative example discloses a method for the clean separation and recovery of molybdenum and vanadium from HDS waste catalyst leachate. 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.

[0167] The vanadium content in the obtained molybdenum-rich raffinate was 8.72 g / L;

[0168] The vanadium content in the obtained vanadium-rich back-extraction solution was 7.62 g / L, corresponding to a vanadium recovery rate of 36.81%. The mass fraction of vanadate in the solid after evaporation, concentration, and crystallization was 63.64%.

[0169] The obtained raffinate contained 19.57 g / L of molybdenum and 5.49 g / L of vanadium.

[0170] The obtained molybdenum-rich back-extraction solution contained 8.61 g / L of vanadium and 10.21 g / L of molybdenum, with a molybdenum recovery rate of 16.37%. The solid after evaporation, concentration, and crystallization contained 37.84% molybdate by mass.

[0171] Analysis of the above results shows that:

[0172] Examples 1-4 illustrate that the present invention uses a limited extraction organic phase to recover molybdenum and vanadium from the leachate of HDS waste catalyst, achieving a vanadium recovery rate of ≥99%, and a vanadate mass fraction of ≥99.5% in the solid after evaporation, concentration, and crystallization; a molybdenum recovery rate of ≥99%, and a molybdate mass fraction of ≥99.5% in the solid after evaporation, concentration, and crystallization.

[0173] Comparing Example 1 and Comparative Examples 1-3, it can be seen that when the pH value of the organic phase system for molybdenum-vanadium extraction is within a certain range, it helps to ensure that molybdenum-vanadium has both good yield and purity, and has good overall economic efficiency.

[0174] Comparative Examples 3 and 4-5 show that when the pH value of the molybdenum-vanadium detergent is within a defined range, it helps to ensure that the molybdenum-vanadium has a good yield and purity, as well as good economic efficiency.

[0175] Compared with Example 3, Comparative Example 6 shows that Comparative Example 6 first extracts molybdenum and then uses the molybdenum extraction raffinate for vanadium extraction. Compared with Example 3, the molybdenum and vanadium yields and product purity are significantly reduced to 47.49% and 47.46%, and 24.34% and 72.95%, respectively.

[0176] Compared with Example 1 and Comparative Examples 7-8, Comparative Examples 7-8, which used an undefined extraction organic method to recover molybdenum and vanadium from the leachate of HDS waste catalyst, showed a significant decrease in molybdenum and vanadium yield and product purity compared with Example 1.

[0177] 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 cleaning and separating and recovering molybdenum and vanadium from a HDS spent catalyst leach solution, characterized by, include: The extraction of vanadium and molybdenum is achieved by adjusting the pH value in the leachate. The organic phase used for the extraction of vanadium and molybdenum has the same composition.

2. The process for cleaning and separation recovery of molybdenum and vanadium from HDS spent catalyst leach liquor as claimed in claim 1 wherein, The extracted organic phase includes quaternary ammonium salt extractants or a mixture of quaternary ammonium salt extractants and tertiary amine extractants.

3. The process for cleaning and separation recovery of molybdenum and vanadium from HDS spent catalyst leach liquor as claimed in claim 2 wherein, The tertiary amine extractant is one or more of a tertiary amine having a substituent group of C8to C 10 isooctyl and N208.

4. The process for cleaning and separation recovery of molybdenum and vanadium from HDS spent catalyst leach liquor as claimed in claim 3 wherein, The substituents are C8to C 10 The tertiary amine is any one of N235, Alamine 336, Adogen 364, Hostarex A327, TOA.

5. The process for cleaning and separation recovery of molybdenum and vanadium from HDS spent catalyst leach liquor as claimed in claim 3 wherein, The tertiary amine with isooctyl substituent is any one of Adogen381, Alamine308, HostarexA324, and Adogen382.

6. The process for cleaning and recovery of molybdenum and vanadium from HDS spent catalyst leach liquor as claimed in claim 2 wherein, The quaternary ammonium salt extractant is one or more of N263, Aliquat336, TOMAC and Adogen464.

7. The process for cleaning separation and recovery of molybdenum and vanadium from HDS spent catalyst leach liquor according to any one of claims 1 to 6, characterized in that, The method for cleanly separating and recovering molybdenum and vanadium from HDS spent catalyst leachate includes: S1. Adjust the HDS waste catalyst leachate to alkaline, and use the extraction organic phase to extract the HDS waste catalyst leachate to obtain vanadium-rich organic phase and molybdenum-rich raffinate. S2. Adjust the molybdenum-rich raffinate to acidity, and use an extractive organic phase to extract the molybdenum-rich raffinate to obtain a molybdenum-rich organic phase and raffinate. S3. The vanadium-rich organic phase and the molybdenum-rich organic phase are back-extracted independently to obtain vanadium-rich back-extracting solution and molybdenum-rich back-extracting solution; S4. The vanadium-rich back-extraction solution and the molybdenum-rich back-extraction solution are processed independently to obtain vanadium and molybdenum products.

8. The process for cleaning and recovery of molybdenum and vanadium from HDS spent catalyst leach liquor as claimed in claim 7 wherein, The pH value of the leaching solution required for vanadium extraction is 8-9.

9. The method for cleanly separating and recovering molybdenum and vanadium from HDS spent catalyst leachate according to claim 7, characterized in that, The pH value of the molybdenum-rich raffinate required for molybdenum extraction is 3-4.

10. The process for cleaning and recovery of molybdenum and vanadium from HDS spent catalyst leach liquor as claimed in claim 7 wherein, Prior to S3, there are steps for washing the vanadium-rich organic phase and refluxing the washing liquid back to the vanadium extraction section as feed, and washing the molybdenum-rich organic phase and refluxing the washing liquid back to the molybdenum extraction section as feed.

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