Extraction agent for extracting and separating tungsten and molybdenum and its application

Abstract

The application provides an extractant for extracting and separating tungsten and molybdenum and an application thereof, and belongs to the technical field of separation of tungsten and molybdenum in hydrometallurgy. The extractant for extracting and separating tungsten and molybdenum comprises 5-35% of secondary diamine, 10-45% of monophosphine oxide and the rest of diluent according to the volume percentage. The extractant comprises secondary diamine and monophosphine oxide, and has the advantages of high extraction efficiency, high separation coefficient and high selectivity when countercurrent extraction is performed on a solution containing tungsten and molybdenum by utilizing the synergistic effect of the steric hindrance of secondary diamine and the Lewis basicity of monophosphine oxide. The results of the examples show that the extraction rate of tungsten can reach 97% and the selectivity can reach 99% when countercurrent extraction is performed on the solution containing tungsten and molybdenum by using the extractant.

Description

Technical Field

[0001] This invention belongs to the field of tungsten and molybdenum separation technology in hydrometallurgy, specifically relating to an extractant for the extraction and separation of tungsten and molybdenum and its application. Background Technology

[0002] Tungsten possesses high melting point, high thermal stability, high hardness, high strength, strong heat and corrosion resistance, and good thermal and electrical conductivity, making it important in many fields. Tungsten is mainly obtained through tungsten ore smelting. Tungsten and molybdenum are transition metal elements, located close to each other in the periodic table, with similar properties, and are common associated elements in minerals. Removing trace amounts of molybdenum from tungsten solutions has always been a very difficult task in the separation and purification of tungsten and molybdenum, and is an increasingly important research topic. Existing methods for tungsten-molybdenum separation mainly include precipitation, ion exchange, and solvent extraction. Solvent extraction, in particular, offers advantages such as high separation efficiency, large throughput, low production cost, and high product purity, making it increasingly popular in industry. The extractant is key to solving the separation and purification of tungsten and molybdenum. Existing extractants, such as complex amine-hydroxyoxime, suffer from low extraction rates and selectivity. Therefore, there is an urgent need for an extractant with high extraction rates and selectivity for separating tungsten and molybdenum. Summary of the Invention

[0003] The purpose of this invention is to provide an extractant for the extraction and separation of tungsten and molybdenum, and its application. The extractant provided by this invention exhibits higher extraction rates and selectivity in the separation of tungsten and molybdenum.

[0004] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0005] This invention provides an extractant for the extraction and separation of tungsten and molybdenum, comprising, by volume percentage, 5-35% diamine, 10-45% monophosphorus oxide, and the balance being a diluent.

[0006] Preferably, the structural formula of the di-secondary amine is shown in Formula I:

[0007]

[0008] In equation I, R 1 and R 2 Independently C1~C 25 Alkyl, C3-C 12 cycloalkyl and C5-C 17 One of the aryl groups; n is an integer from 1 to 20.

[0009] Preferably, the structural formula of the single phosphorus oxide is shown in Formula II:

[0010]

[0011] In formula II, R 3 R 4 and R 5 Independently C1~C 40 Alkyl, C3-C 20 cycloalkyl and C5-C 18 One of the aryl groups.

[0012] Preferably, the diluent comprises one or more of the following: white oil, kerosene, sulfonated kerosene, n-hexane, cyclohexane, carbon disulfide, dichloromethane, dichloroethane, chloroform, carbon tetrachloride, methyl acetate, ethyl acetate, octanol, hexadecyl alcohol, dichlorobenzene, trichlorobenzene, toluene, and xylene.

[0013] The present invention also provides the application of the extractant described in the above technical solution for the extraction and separation of tungsten and molybdenum in the separation of tungsten and molybdenum.

[0014] Preferably, the application includes the following steps:

[0015] (1) The extractant for separating tungsten and molybdenum is subjected to countercurrent extraction with a solution containing tungsten and molybdenum to obtain an extract;

[0016] (2) The extract obtained in step (1) is subjected to countercurrent back-extraction with the back-extraction agent to obtain a tungsten-containing solution and an extractant.

[0017] Preferably, in step (1), the volume ratio of the extractant for separating tungsten and molybdenum to the solution containing tungsten and molybdenum is (1-5):1.

[0018] Preferably, the number of countercurrent extraction stages in step (1) is 1 to 15, and the temperature of countercurrent extraction is 10 to 70°C.

[0019] Preferably, the back-extraction agent in step (2) includes one or more of water, sodium hydroxide solution, potassium hydroxide solution, ammonia solution, ammonium carbonate solution, ammonium bicarbonate solution, hydroxylamine solution, sodium carbonate solution, and sodium bicarbonate solution.

[0020] Preferably, the number of countercurrent back-extraction stages in step (2) is 1 to 3, and the temperature of countercurrent back-extraction is 15 to 75°C.

[0021] This invention provides an extractant for the extraction and separation of tungsten and molybdenum, comprising, by volume percentage, 5-35% diamine, 10-45% monophosphorus oxide, and the balance being a diluent. The extractant provided by this invention, comprising diamine and monophosphorus oxide, utilizes the synergistic effect of the large steric hindrance of the diamine and the Lewis basicity of the monophosphorus oxide to achieve high extraction rate, high separation coefficient, and high selectivity when performing countercurrent extraction on solutions containing tungsten and molybdenum. Results from examples show that, using the extractant provided by this invention for countercurrent extraction of solutions containing tungsten and molybdenum, the tungsten extraction rate can reach 97%, and the selectivity can reach 99%. Detailed Implementation

[0022] This invention provides an extractant for the extraction and separation of tungsten and molybdenum, comprising, by volume percentage, 5-35% diamine, 10-45% monophosphorus oxide, and the balance being a diluent.

[0023] Unless otherwise specified, the present invention does not have any special limitations on the source of each component, and commercially available products well known to those skilled in the art can be used.

[0024] The extractant provided by this invention comprises 5-35% diamine by volume percentage. As one embodiment, the volume percentage of the diamine may specifically be 5%, 10%, 15%, 20%, 25%, 30%, or 35%.

[0025] In this invention, the preferred structural formula of the diamine is shown in Formula I:

[0026]

[0027] In this invention, in formula I, R 1 and R 2 Independently preferred are C1 to C 25 Alkyl, C3-C 12 cycloalkyl and C5-C 17 One of the aryl groups. As one embodiment, the R... 1 and R 2 It can be independently phenyl, butyl, pentyl, hexyl or cyclohexyl.

[0028] In this invention, in Formula I, n is preferably an integer from 1 to 20. As one embodiment, n can specifically be 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19 or 20.

[0029] This invention controls the structure and dosage of the di-secondary amine within the above-mentioned range, and can utilize the large steric hindrance of the di-secondary amine and the synergistic effect of the monophosphorus oxide to further improve the extraction rate, selectivity and separation coefficient.

[0030] The extractant provided by this invention further includes 10-45% monophosphorus oxide by volume percentage. As one embodiment, the volume percentage of the monophosphorus oxide may specifically be 10%, 15%, 20%, 25%, 30%, 35%, 40%, or 45%.

[0031] In this invention, the preferred structural formula of the single phosphorus oxide is shown in Formula II:

[0032]

[0033] In this invention, in formula II, R 3 R 4 and R 5 Independently preferred are C1 to C 40 Alkyl, C3-C 20 cycloalkyl and C5-C 18 One of the aryl groups. As one embodiment, the R... 3 R 4 and R 5 It can be independently cyclohexyl, propyl, methyl, ethyl, phenyl, isobutyl, cyclopentyl, butyl, or 4-tert-butylcyclohexyl.

[0034] This invention controls the structure and amount of monophosphorus oxide within the above-mentioned range, and can utilize the Lewis basicity of monophosphorus oxide and the synergistic effect of di-secondary amines to further improve the extraction rate, selectivity and separation coefficient.

[0035] The extractant provided by this invention, by volume percentage, also includes a balance of diluent.

[0036] In this invention, the diluent preferably includes one or more of the following: white oil, kerosene, sulfonated kerosene, n-hexane, cyclohexane, carbon disulfide, dichloromethane, dichloroethane, chloroform, carbon tetrachloride, methyl acetate, ethyl acetate, octanol, hexadecyl alcohol, dichlorobenzene, trichlorobenzene, toluene, and xylene. This invention controls the amount and type of diluent within the above-mentioned ranges, ensuring sufficient dissolution of all components.

[0037] This invention uses bis-secondary amine and monophosphorus oxide as extractants. By utilizing the synergistic effect of the large steric hindrance of bis-secondary amine and the Lewis basicity of monophosphorus oxide, it has the advantages of high extraction rate, high separation coefficient and high selectivity when performing countercurrent extraction on solutions containing tungsten and molybdenum. At the same time, the extractant has the advantages of low price and small organic phase loss, making it an extractant with great industrial applications.

[0038] The present invention does not impose any special limitations on the preparation method of the extractant for the extraction and separation of tungsten and molybdenum, as long as the components are mixed evenly.

[0039] The present invention also provides the application of the extractant described in the above technical solution for the extraction and separation of tungsten and molybdenum in the separation of tungsten and molybdenum.

[0040] In this invention, the application preferably includes the following steps:

[0041] (1) The extractant for separating tungsten and molybdenum is subjected to countercurrent extraction with a solution containing tungsten and molybdenum to obtain an extract;

[0042] (2) The extract obtained in step (1) is subjected to countercurrent back-extraction with the back-extraction agent to obtain a tungsten-containing solution and an extractant.

[0043] In this invention, the extractant for separating tungsten and molybdenum is preferably subjected to countercurrent extraction with a solution containing tungsten and molybdenum to obtain an extract.

[0044] The present invention does not have any special limitation on the source of the tungsten and molybdenum-containing solution; the tungsten and molybdenum-containing solution that needs to be separated can be selected according to actual needs.

[0045] In this invention, the preferred volume ratio of the extractant for separating tungsten and molybdenum to the solution containing tungsten and molybdenum is (1-5):1. As one embodiment, the volume ratio of the extractant for separating tungsten and molybdenum to the solution containing tungsten and molybdenum can be specifically 1:1, 1:2, 1:3, 1:4, or 1:5.

[0046] In this invention, the number of stages of countercurrent extraction is preferably 1 to 15. As one embodiment, the number of stages of countercurrent extraction can specifically be 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, or 15 stages.

[0047] In this invention, the temperature of the countercurrent extraction is preferably 10–70°C. As one embodiment, the temperature of the countercurrent extraction can specifically be 10°C, 20°C, 30°C, 40°C, 50°C, 60°C, or 70°C.

[0048] In this invention, the countercurrent extraction time is preferably 5 to 40 minutes.

[0049] This invention controls the parameters during countercurrent extraction within the above-mentioned range, which can further improve the extraction rate.

[0050] In this invention, during the countercurrent extraction process, tungsten is extracted into the extractant to obtain an extract solution.

[0051] After obtaining the extract, the present invention preferably performs countercurrent back-extraction with the extractant to obtain a tungsten-containing solution and an extractant.

[0052] In this invention, the back-extraction agent preferably includes one or more of water, sodium hydroxide solution, potassium hydroxide solution, ammonia solution, ammonium carbonate solution, ammonium bicarbonate solution, hydroxylamine solution, sodium carbonate solution, and sodium bicarbonate solution.

[0053] In this invention, the preferred mass concentration of the sodium hydroxide solution is 10-35%; the preferred mass concentration of the potassium hydroxide solution is 10-35%; the preferred mass concentration of the ammonia solution is 10-30%; the preferred mass concentration of the ammonium carbonate solution is 20-45%; the preferred mass concentration of the ammonium bicarbonate solution is 20-45%; the preferred mass concentration of the hydroxylamine solution is 25-40%; the preferred mass concentration of the sodium carbonate solution is 20-30%; and the preferred mass concentration of the sodium bicarbonate solution is 20-30%.

[0054] In this invention, the preferred volume ratio of the extract to the back-extraction agent is (2-6):1. As one embodiment, the volume ratio of the extract to the back-extraction agent can specifically be 2:1, 3:1, 4:1, 5:1, or 6:1.

[0055] In this invention, the number of stages in the countercurrent back-extraction is preferably 1 to 3. As one embodiment, the number of stages in the countercurrent back-extraction can specifically be 1, 2, or 3.

[0056] In this invention, the temperature of the countercurrent back-extraction is preferably 15–75°C. As one embodiment, the temperature of the countercurrent back-extraction can specifically be 15°C, 20°C, 25°C, 30°C, 35°C, 40°C, 45°C, 50°C, 55°C, 60°C, 65°C, 70°C, or 75°C.

[0057] In this invention, the countercurrent back-extraction time is preferably 1 to 10 minutes.

[0058] This invention controls the parameters during countercurrent back-extraction within the above-mentioned range, which can further improve the extraction rate.

[0059] In this invention, during the countercurrent back-extraction process, tungsten in the extract is back-extracted into the back-extracting agent to obtain a tungsten-containing solution.

[0060] In this invention, the extractant obtained by the countercurrent back-extraction is preferably recycled.

[0061] In this invention, the countercurrent extraction and countercurrent back-extraction are preferably carried out in a mixing and clarification tank, an extraction tower, or a centrifugal extractor. This invention does not impose any particular limitation on the model of the mixing and clarification tank, extraction tower, or centrifugal extractor; any equipment well-known to those skilled in the art can be used.

[0062] The extraction process of this invention is simple, consisting of only two steps: extraction and back-extraction. The extractant does not require pretreatment such as saponification, which reduces the use of reagents such as acids and alkalis. It also has low equipment requirements and is economical.

[0063] The technical solutions of this invention will be clearly and completely described below with reference to the embodiments thereof. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0064] Example 1

[0065] An extractant for the extraction and separation of tungsten and molybdenum, by volume percentage, consists of 5% of the secondary amine N,N-diphenylbutanediamine (CAS: 13170-61-1), 10% of the monophosphorus oxide tricyclohexylphosphonium oxide (CAS: 13689-19-5), and the balance being the diluent dichloromethane.

[0066] The method for preparing the extractant for the extraction and separation of tungsten and molybdenum is as follows: N,N-diphenylbutanediamine, tricyclohexylphosphine, and dichloromethane are mixed at room temperature and stirred evenly to obtain the extractant.

[0067] Application Example 1

[0068] (1) The extractant in Example 1 and a solution containing sodium tungstate and sodium molybdate (tungsten ion concentration of 19.0 g / L and molybdenum ion concentration of 1.3 g / L) were subjected to countercurrent extraction using a centrifugal extractor. The volume ratio of the extractant to the solution containing sodium tungstate and sodium molybdate was 1:1. The number of countercurrent extraction stages was 4. The temperature of the countercurrent extraction was 15°C. The time of the countercurrent extraction was 9 min, and the extract was obtained.

[0069] (2) The extract obtained in step (1) and the back-extraction agent (water) are subjected to countercurrent back-extraction using a centrifugal extractor. The volume ratio of the extract to the back-extraction agent is 2:1, the number of countercurrent back-extraction stages is 1, the temperature of countercurrent back-extraction is 20℃, and the time of countercurrent back-extraction is 3min to obtain a tungsten-containing solution.

[0070] The tungsten-containing solution (sodium tungstate solution) obtained in Application Example 1 was directly analyzed by ICP-MS to determine the content of sodium tungstate and sodium molybdate in the solution, and the purity of the tungsten-containing solution was obtained.

[0071] In Application Example 1, the extraction rate was 73%, and the purity of the tungsten-containing solution (sodium tungstate) was 80%.

[0072] Comparative Example 1

[0073] An extractant, by volume percentage, consists of 15% of the secondary amine N,N-diphenylbutanediamine (CAS: 13170-61-1) and the balance diluent dichloromethane;

[0074] The extraction agent is prepared by mixing N,N-diphenylbutane and dichloromethane at room temperature and stirring until homogeneous to obtain the extraction agent.

[0075] Comparative Application Example 1

[0076] The extractant in Example 1 of Application Example 1 was replaced with the extractant in Comparative Example 1, and all other parameters were the same as in Application Example 1, resulting in a tungsten-containing solution.

[0077] In comparison, the extraction rate in Application Example 1 was 33%, and the purity of the tungsten-containing solution was 65%.

[0078] Comparative Example 2

[0079] An extractant, by volume percentage, consists of 15% tricyclohexylphosphine oxide (CAS: 13689-19-5) and the balance diluent dichloromethane.

[0080] The extraction agent is prepared by mixing tricyclohexylphosphine and dichloromethane at room temperature and stirring until homogeneous to obtain the extraction agent.

[0081] Comparative Application Example 2

[0082] The extractant in Example 1 of Application Example 1 was replaced with the extractant in Comparative Example 2, and all other parameters were the same as in Application Example 1, resulting in a tungsten-containing solution.

[0083] In comparison, the extraction rate in Application Example 2 was 23%, and the purity of the tungsten-containing solution was 66%.

[0084] Example 2

[0085] An extractant for the extraction and separation of tungsten and molybdenum, by volume percentage, consists of 10% of the secondary amine N,N-diphenylpropanediamine (CAS: 104-69-8), 15% of the monophosphorus oxide dipropylcyclohexylphosphoxide (CAS: 73986-82-0), and the balance being the diluent kerosene.

[0086] The method for preparing the extractant for separating tungsten and molybdenum is as follows: N,N-diphenylpropanediamine, dipropylcyclohexylphosphine and kerosene are mixed at room temperature and stirred evenly to obtain the extractant.

[0087] Application Example 2

[0088] (1) The extractant in Example 2 and a solution containing sodium tungstate and sodium molybdate (tungsten ion concentration of 35.0 g / L and molybdenum ion concentration of 2.3 g / L) were subjected to countercurrent extraction using a centrifugal extractor. The volume ratio of the extractant to the solution containing sodium tungstate and sodium molybdate was 2:1. The number of countercurrent extraction stages was 5. The temperature of the countercurrent extraction was 20°C. The time of the countercurrent extraction was 10 min to obtain the extract.

[0089] (2) The extract obtained in step (1) and the back-extraction agent (ammonium carbonate solution with a mass concentration of 25%) were subjected to countercurrent back-extraction using a centrifugal extractor. The volume ratio of the extract to the back-extraction agent was 3:1, the number of countercurrent back-extraction stages was 2, the temperature of the countercurrent back-extraction was 30℃, and the time of the countercurrent back-extraction was 2min, resulting in a tungsten-containing solution.

[0090] In Application Example 2, the extraction rate was 87%, and the purity of the tungsten-containing solution was 85%.

[0091] Example 3

[0092] An extractant for the extraction and separation of tungsten and molybdenum, by volume percentage, consists of 15% of the secondary amine N,N-diphenylethylenediamine (CAS: 150-61-8), 20% of the monophosphorus oxide methyl dicyclohexylphosphoxide (CAS: 42366-52-9), and the balance being the diluent cyclohexane.

[0093] The method for preparing the extractant for the extraction and separation of tungsten and molybdenum is as follows: N,N-diphenylethylenediamine, methyldicyclohexylphosphine and cyclohexane are mixed at room temperature and stirred evenly to obtain the extractant.

[0094] Application Example 3

[0095] (1) The extractant in Example 3 and a solution containing sodium tungstate and sodium molybdate (tungsten ion concentration of 69.0 g / L and molybdenum ion concentration of 1.1 g / L) were subjected to countercurrent extraction using a centrifugal extractor. The volume ratio of the extractant to the solution containing sodium tungstate and sodium molybdate was 3:1. The number of countercurrent extraction stages was 6. The temperature of the countercurrent extraction was 25°C. The time of the countercurrent extraction was 9 min. The extract was obtained.

[0096] (2) The extract obtained in step (1) and the back-extraction agent (ammonia water, mass concentration of 30%) were subjected to countercurrent back-extraction using a centrifugal extractor. The volume ratio of the extract to the back-extraction agent was 3:1, the number of countercurrent back-extraction stages was 2, the temperature of countercurrent back-extraction was 30℃, and the time of countercurrent back-extraction was 1 min, to obtain a tungsten-containing solution.

[0097] In Application Example 3, the extraction rate was 91%, and the purity of the tungsten-containing solution was 97.5%.

[0098] Example 4

[0099] An extractant for the extraction and separation of tungsten and molybdenum, by volume percentage, consists of 20% of the secondary amine N,N-diphenylmethanediamine (CAS: 622-14-0), 25% of the monophosphorus oxide diethylcyclohexylphosphorus oxide (CAS: 13689-18-4), and the balance being the diluent toluene.

[0100] The method for preparing the extractant for the extraction and separation of tungsten and molybdenum is as follows: N,N-diphenylmethanediamine, diethylcyclohexylphosphine, and toluene are mixed at room temperature and stirred evenly to obtain the extractant.

[0101] Application Example 4

[0102] (1) The extractant from Example 4 and a solution containing sodium tungstate and sodium molybdate (tungsten ion concentration of 83.0 g / L and molybdenum ion concentration of 11.2 g / L) were subjected to countercurrent extraction using a centrifugal extractor. The volume ratio of the extractant to the solution containing sodium tungstate and sodium molybdate was 2:1. The number of stages of countercurrent extraction was 4. The temperature of countercurrent extraction was 29°C. The time of countercurrent extraction was 5 min. The extract was obtained.

[0103] (2) The extract obtained in step (1) and the back-extraction agent (hydroxylamine solution, mass concentration of 35%) were subjected to countercurrent back-extraction using a centrifugal extractor. The volume ratio of extract to back-extraction agent was 4:1, the number of countercurrent back-extraction stages was 1, the temperature of countercurrent back-extraction was 33℃, and the time of countercurrent back-extraction was 1 min, to obtain a tungsten-containing solution.

[0104] In Application Example 4, the extraction rate was 88%, and the purity of the tungsten-containing solution was 90%.

[0105] Example 5

[0106] An extractant for the extraction and separation of tungsten and molybdenum, by volume percentage, consists of 25% of the secondary amine N,N-dibutylethylenediamine (CAS:4013-95-0), 30% of the monophosphorus oxide triphenylphosphine (CAS:791-28-6), and the balance being the diluent chloroform;

[0107] The method for preparing the extractant for the extraction and separation of tungsten and molybdenum is as follows: N,N-dibutylethylenediamine, triphenylphosphine oxide and chloroform are mixed at room temperature and stirred evenly to obtain the extractant.

[0108] Application Example 5

[0109] (1) The extractant in Example 5 and a solution containing sodium tungstate and sodium molybdate (tungsten ion concentration of 79.0 g / L and molybdenum ion concentration of 4.4 g / L) were subjected to countercurrent extraction using a centrifugal extractor. The volume ratio of the extractant to the solution containing sodium tungstate and sodium molybdate was 2:1. The number of countercurrent extraction stages was 4. The temperature of the countercurrent extraction was 60°C. The time of the countercurrent extraction was 10 min. The extract was obtained.

[0110] (2) The extract obtained in step (1) and the back-extraction agent (sodium hydroxide solution, mass concentration of 15%) were subjected to countercurrent back-extraction using a centrifugal extractor. The volume ratio of extract to back-extraction agent was 5:1, the number of countercurrent back-extraction stages was 1, the temperature of countercurrent back-extraction was 63℃, and the time of countercurrent back-extraction was 1 min, to obtain a tungsten-containing solution.

[0111] In Application Example 5, the extraction rate was 91%, and the purity of the tungsten-containing solution was 90%.

[0112] Example 6

[0113] An extractant for the extraction and separation of tungsten and molybdenum, by volume percentage, consists of 30% of the secondary amine N,N-dipentylethylenediamine (CAS: 88619-07-2), 35% of the monophosphorus oxide diisobutylcyclohexylphosphonate (CAS: 52911-34-9), and the balance being a diluent (cyclohexane and kerosene in a volume ratio of 2:1).

[0114] The method for preparing the extractant for the extraction and separation of tungsten and molybdenum is as follows: N,N-dipentylethylenediamine, diisobutylcyclohexylphosphine, cyclohexane and kerosene are mixed at room temperature and stirred evenly to obtain the extractant.

[0115] Application Example 6

[0116] (1) The extractant from Example 6 and a solution containing sodium tungstate and sodium molybdate (tungsten ion concentration of 108.0 g / L and molybdenum ion concentration of 2.8 g / L) were subjected to countercurrent extraction using a centrifugal extractor. The volume ratio of the extractant to the solution containing sodium tungstate and sodium molybdate was 5:1. The number of countercurrent extraction stages was 3. The temperature of the countercurrent extraction was 34°C. The time of the countercurrent extraction was 15 min, and the extract was obtained.

[0117] (2) The extract obtained in step (1) and the back-extraction agent (potassium hydroxide solution, mass concentration of 20%) were subjected to countercurrent back-extraction using a centrifugal extractor. The volume ratio of extract to back-extraction agent was 4:1, the number of stages of countercurrent back-extraction was 1, the temperature of countercurrent back-extraction was 42℃, and the time of countercurrent back-extraction was 5min, to obtain a tungsten-containing solution.

[0118] In Application Example 6, the extraction rate was 89%, and the purity of the tungsten-containing solution was 94%.

[0119] Example 7

[0120] An extractant for the extraction and separation of tungsten and molybdenum, by volume percentage, consists of 35% of the secondary amine N,N-dihexylethylenediamine (CAS: 57413-98-6), 40% of the monophosphorus oxide dibutylcyclopentylphosphonate (CAS: 17636-47-4), and the balance being a diluent (dichlorobenzene and chloroform in a volume ratio of 4:1).

[0121] The method for preparing the extractant for the extraction and separation of tungsten and molybdenum is as follows: N,N-dihexylethylenediamine, dibutylcyclopentylphosphine, dichlorobenzene and chloroform are mixed at room temperature and stirred evenly to obtain the extractant.

[0122] Application Example 7

[0123] (1) The extractant from Example 7 and a solution containing sodium tungstate and sodium molybdate (tungsten ion concentration of 274.0 g / L and molybdenum ion concentration of 22.0 g / L) were subjected to countercurrent extraction using a centrifugal extractor. The volume ratio of the extractant to the solution containing sodium tungstate and sodium molybdate was 1:1. The number of countercurrent extraction stages was 6. The temperature of the countercurrent extraction was 49°C. The time of the countercurrent extraction was 11 min, and the extract was obtained.

[0124] (2) The extract obtained in step (1) and the back-extraction agent (sodium bicarbonate solution with a mass concentration of 20%) were subjected to countercurrent back-extraction using a centrifugal extractor. The volume ratio of the extract to the back-extraction agent was 5:1, the number of countercurrent back-extraction stages was 3, the temperature of the countercurrent back-extraction was 53℃, and the time of the countercurrent back-extraction was 3min, resulting in a tungsten-containing solution.

[0125] In Application Example 7, the extraction rate was 82%, and the purity of the tungsten-containing solution was 91.5%.

[0126] Example 8

[0127] An extractant for the extraction and separation of tungsten and molybdenum, by volume percentage, consists of 20% of bis(cyclohexylamino)ethane (CAS: 811-017-5), 45% of tris(4-tert-butylcyclohexyl)phosphorus oxide (CAS: 786697-23-2), and the balance being a diluent (cyclohexane and sulfonated kerosene in a volume ratio of 3:1).

[0128] The method for preparing the extractant for the extraction and separation of tungsten and molybdenum is as follows: 1,2-bis(cyclohexylamino)ethane, tris(4-tert-butylcyclohexyl)phosphine, cyclohexane and sulfonated kerosene are mixed at room temperature and stirred evenly to obtain the extractant.

[0129] Application Example 8

[0130] (1) The extractant from Example 8 and a solution containing sodium tungstate and sodium molybdate (tungsten ion concentration of 174.0 g / L and molybdenum ion concentration of 15.6 g / L) were subjected to countercurrent extraction using a centrifugal extractor. The volume ratio of the extractant to the solution containing sodium tungstate and sodium molybdate was 2:1. The number of countercurrent extraction stages was 9. The temperature of the countercurrent extraction was 40°C. The time of the countercurrent extraction was 35 min, and the extract was obtained.

[0131] (2) The extract obtained in step (1) and the back-extraction agent (ammonium carbonate solution, mass concentration of 25%) were subjected to countercurrent back-extraction using a centrifugal extractor. The volume ratio of extract to back-extraction agent was 3:1, the number of countercurrent back-extraction stages was 2, the temperature of countercurrent back-extraction was 45℃, and the time of countercurrent back-extraction was 10min to obtain a tungsten-containing solution.

[0132] In Application Example 8, the extraction rate was 97%, and the purity of the tungsten-containing solution was 99%.

[0133] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. An extractant for the extraction and separation of tungsten and molybdenum, comprising, by volume percentage, 5-35% diamine, 10-45% monophosphorus oxide, and the balance being a diluent; The structural formula of the di-secondary amine is shown in Formula I: Formula I; In equation I, R 1 and R 2 It can be phenyl, butyl, pentyl, hexyl or cyclohexyl independently; n is an integer from 1 to 20; The structural formula of the single phosphorus oxide is shown in Formula II: Formula II; In formula II, R 3 R 4 and R 5 It is independently cyclohexyl, propyl, methyl, ethyl, phenyl, isobutyl, cyclopentyl, butyl, or 4-tert-butylcyclohexyl.

2. The extractant according to claim 1, characterized in that, The diluent includes one or more of the following: white oil, kerosene, sulfonated kerosene, n-hexane, cyclohexane, carbon disulfide, dichloromethane, dichloroethane, chloroform, carbon tetrachloride, methyl acetate, ethyl acetate, octanol, hexadecyl alcohol, dichlorobenzene, trichlorobenzene, toluene, and xylene.

3. The application of the extractant for separating tungsten and molybdenum as described in any one of claims 1 to 2 in the separation of tungsten and molybdenum.

4. The application according to claim 3, characterized in that, Includes the following steps: (1) The extractant for separating tungsten and molybdenum is subjected to countercurrent extraction with a solution containing tungsten and molybdenum to obtain an extract; (2) The extract obtained in step (1) is subjected to countercurrent back-extraction with the back-extraction agent to obtain a tungsten-containing solution and an extractant.

5. The application according to claim 4, characterized in that, In step (1), the volume ratio of the extractant for separating tungsten and molybdenum to the solution containing tungsten and molybdenum is 1~5:

1.

6. The application according to claim 4, characterized in that, In step (1), the number of countercurrent extraction stages is 1 to 15, and the temperature of countercurrent extraction is 10 to 70°C.

7. The application according to claim 4, characterized in that, The back-extraction agent in step (2) includes one or more of the following: water, sodium hydroxide solution, potassium hydroxide solution, ammonia solution, ammonium carbonate solution, ammonium bicarbonate solution, hydroxylamine solution, sodium carbonate solution, and sodium bicarbonate solution.

8. The application according to claim 4, characterized in that, In step (2), the number of countercurrent back-extraction stages is 1 to 3, and the temperature of countercurrent back-extraction is 15 to 75°C.

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