Tungsten extraction agent, preparation method thereof and method for extracting and separating tungsten

Abstract

The invention provides a tungsten extraction agent, a preparation method thereof and a method for extracting and separating tungsten, and belongs to the field of metal extraction and separation in hydrometallurgy. The extraction agent is composed of the bis-secondary amine, the bis-phosphorus oxide and the diluent, the bis-secondary amine has a unique space structure and alkalinity, the bis-phosphorus oxide has different chemical structures and properties compared with P204, the synergistic effect of the bis-secondary amine and the bis-phosphorus oxide is utilized, high selectivity can be achieved on tungstate in the extraction process, and the extraction efficiency is improved. Tungstate containing molybdenum metal is directly extracted, so that a high-purity tungstate product is obtained through purification and separation; the extraction agent provided by the invention does not need saponification and other pretreatment, does not need to add acid or alkali, reduces the use of acid and alkali and other reagents, and is environment-friendly, low in equipment requirement, good in economical efficiency and simple and efficient in extraction process; different extraction agent formulas can be selected according to different tungsten molybdate systems, and the extraction agents are flexible and changeable.

Description

Technical Field

[0001] The invention relates to the field of metal extraction and separation in hydrometallurgy, and in particular to a tungsten extractant and a preparation method thereof, and a method for extracting and separating tungsten. Background Art

[0002] Tungsten has high melting point, high thermal stability, high hardness, high strength, strong heat and corrosion resistance, good thermal and electrical conductivity, and is an indispensable additive in the steel industry. Tungsten metal can be used as an alloy component in the production of different types of alloy steels to improve the corrosion resistance of various alloy steels; tungsten is a good chemical and petroleum catalyst. As a chemical catalyst, it is often used in various chemical reactions to catalyze inorganic and organic chemical reactions; tungsten oxide can also be used in solar cells, photocatalysis, water decomposition and electroluminescent devices. With the advancement of human science and technology, the application field of tungsten is constantly expanding, and its application prospects are very broad.

[0003] my country's tungsten metallurgical output accounts for about 80% of the world's total tungsten output, but high-quality wolframite resources are gradually depleted. Although scheelite has large reserves, most of it is a complex mineral resource with multi-metallic associations, making it difficult to extract high-purity tungsten. Tungsten and molybdenum often coexist in minerals and metallurgical intermediates. Due to their very similar chemical properties, it is very difficult to separate tungsten and molybdenum.

[0004] In the separation and purification of tungsten and molybdenum, removing trace amounts of molybdenum from tungsten solutions has always been one of the topics of concern to scientific researchers. The main methods for separating tungsten and molybdenum currently include precipitation, ion exchange and solvent extraction. Among them, solvent extraction has the advantages of high separation efficiency, large processing capacity, low production cost and high product purity, and is increasingly popular in industry. For example, in patent CN102140578B, a tungsten and molybdenum separation process is disclosed for cooling and crystallizing ammonium tetrathiomolybdate from an ammonium tungstate solution containing a high concentration of molybdenum. The ammonium tungstate solution is first subjected to thiolation treatment so that the molybdenum in the solution is preferentially generated into ammonium tetrathiomolybdate. Without adding any other chemical reagents, by lowering the solution temperature, ammonium tetrathiomolybdate is preferentially precipitated, while tungstate is not precipitated, thereby separating and purifying tungsten and molybdenum; in patent CN102925685B, a composite solvent for extracting and separating tungsten and molybdenum is disclosed, which is composed of a secondary carbon primary amine and di-(2-ethylhexyl)phosphine. Acid is mixed, and the composite solvent is used to perform extraction, countercurrent washing and stripping operations in sequence to achieve tungsten and molybdenum separation; in patent CN103320612B, a composite amine-hydroxamic extractant is disclosed, which is used to separate tungsten and molybdenum from a solution containing tungsten molybdate, and the coefficient of tungsten and molybdenum separation is large, and tungsten in sodium molybdate can be removed and sodium molybdate solution can be purified; in patent CN118272653A, the use of an extractant containing amino neutral phosphine is disclosed for separating tungsten and molybdenum, and the extractant used does not need to be saponified in advance, which reduces the use of acid and alkali reagents and improves the economy in the separation process. However, the above-mentioned problems such as low extraction efficiency, high cost of extractant and large wastewater discharge seriously limit its application in industrialization.

[0005] Therefore, how to provide an efficient, economical and environmentally friendly extractant for the separation and purification of tungsten and molybdenum has become a technical problem to be solved urgently in this field. Summary of the invention

[0006] The purpose of the present invention is to provide a tungsten extractant and a preparation method thereof and a method for extracting and separating tungsten. The tungsten extractant provided by the present invention does not require saponification or activation of the extractant when used for extracting and separating tungsten, and does not require the use of acid, alkali or oxidant. At the same time, the tungsten extraction rate and purity are high. In addition, the tungsten extractant can be reused after back extraction, which is green and environmentally friendly.

[0007] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0008] The invention provides a tungsten extractant, which comprises the following components by volume percentage: 1-45% of di-secondary amine, 10-50% of diphosphorus oxide and the remainder of diluent.

[0009] Preferably, the structure of the di-secondary amine is The n is 1 to 20; the R 1 and R 2Independently C1~C 30 Alkyl, C3~C8 cycloalkyl and C5~C 15 Any of the aromatic groups.

[0010] Preferably, the structure of the diphosphorus oxide is The n is 1 to 20; the R 3 , R 4 , R 5 and R 6 Independently C1~C 30 Alkyl, C3~C 10 Cycloalkyl and C5~C 19 Any of the aromatic groups.

[0011] Preferably, the diluent comprises one or more of white oil, kerosene, sulfonated kerosene, n-hexane, cyclohexane, carbon disulfide, dichloromethane, dichloroethane, chloroform, carbon tetrachloride, methyl acetate, ethyl acetate, octanol, dichlorobenzene, trichlorobenzene, toluene and xylene.

[0012] The present invention provides a method for preparing the tungsten extractant described in the above technical solution, comprising: mixing di-secondary amine, diphosphorus oxide and a diluent to obtain the tungsten extractant.

[0013] The present invention also provides a method for extracting and separating tungsten, using a tungsten extractant to perform countercurrent extraction on an extract, and then performing back extraction to obtain high-purity tungstate; the tungsten extractant is the tungsten extractant described in the above technical solution or the tungsten extractant prepared by the preparation method described in the above technical solution.

[0014] Preferably, the volume ratio of the tungsten extractant to the liquid to be extracted is 1:(1-10).

[0015] Preferably, the number of stages of the countercurrent extraction is 1 to 10; the temperature of the countercurrent extraction is 10 to 70°C.

[0016] Preferably, the stripping agent used for the stripping includes one or more of water, ammonium carbonate solution, ammonium bicarbonate solution, ammonia solution, hydroxylamine solution, sodium carbonate solution, sodium bicarbonate solution, sodium hydroxide solution and potassium hydroxide solution.

[0017] Preferably, the number of stages of the stripping is 1 to 5; the temperature of the stripping is 15 to 80°C.

[0018] The present invention provides a tungsten extractant, which comprises the following components by volume percentage: 1-45% of di-secondary amine, 10-50% of diphosphorus oxide and the remainder of diluent. The present invention uses di-secondary amine, diphosphorus oxide and diluent to form the extractant, the di-secondary amine has a unique spatial structure and alkalinity, and the diphosphorus oxide has different chemical structures and properties compared with P204. By utilizing the synergistic effect of di-secondary amine and diphosphorus oxide, the tungstate can be highly selective in the extraction process, and the tungstate containing molybdenum metal can be directly extracted, thereby purifying and separating to obtain a high-purity tungstate product; the extractant provided by the present invention does not need to be pre-treated by saponification, does not need to add acid or alkali, reduces the use of acid and alkali reagents, is environmentally friendly, has low equipment requirements, good economy, and a simple and efficient extraction process; different extractant formulas can be selected for different tungstate molybdate systems, and the extractant is flexible and changeable; in addition, the diluent is cheap and easy to obtain, and the cost is low, and after stripping, the extractant can be reused, which is green and environmentally friendly, greatly reduces the production and use costs of the tungsten extractant, improves the market competitiveness of the tungsten extractant, and is conducive to large-scale industrial promotion. The results of the examples show that after the mixed solution of sodium tungstate and sodium molybdate is extracted by the tungsten extractant provided by the present invention, the extraction rate of sodium tungstate can reach up to 99%, and the purity of sodium tungstate is high and the impurities are few, and the purity can reach up to 99%. DETAILED DESCRIPTION

[0019] The invention provides a tungsten extractant, which comprises the following components by volume percentage: 1-45% of di-secondary amine, 10-50% of diphosphorus oxide and the remainder of diluent.

[0020] The tungsten extractant provided by the present invention comprises 1 to 45% of di-secondary amine by volume percentage. In the present invention, the structure of the di-secondary amine is preferably The n is preferably 1 to 20, more preferably 1 to 10; the R 1 and R 2 Preferably, C1 to C 30 Alkyl, C3~C8 cycloalkyl and C5~C 15 Any of the aryl groups, more preferably C4 to C 16 Alkyl, C4-C7 cycloalkyl and C5-C 10 Any of the aromatic groups.

[0021] As an embodiment of the present invention, the volume percentage of the di-secondary amine can be 1%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40% or 45%; the di-secondary amine can be N,N-diphenylethylenediamine (CAS: 150-61-8), N,N-dipentylethylenediamine (CAS: 88619-07-2), N,N-dihexylethylenediamine (CAS: 57413-98-6), 1,2-bis(cyclohexylamino)ethane (CAS: 811-017-5), N,N-diphenylmethanediamine (CAS: 622-14-0), N,N-diphenylbutanediamine (CAS: 104-69-8), N,N-dibutylethylenediamine (CAS: 4013-95-0) or N,N-diphenylbutanediamine (CAS: 13170-61-1).

[0022] The tungsten extractant provided by the present invention comprises 10 to 50% of diphosphorus oxide by volume. In the present invention, the structure of the diphosphorus oxide is preferably The n is preferably 1 to 20, more preferably 1 to 10; the R 3 , R 4 , R 5 and R 6 Preferably, C1 to C 30 Alkyl, C3~C 10 Cycloalkyl and C5~C 19 Any of the aryl groups, more preferably C4 to C 12 Alkyl, C4~C8 cycloalkyl and C5~C 10 Any of the aromatic groups.

[0023] As an embodiment of the present invention, the volume percentage of the bisphosphorus oxide can be 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45% or 50%; the bisphosphorus oxide can be [4-(diphenylphosphine oxide) butyl] ethylphenylphosphine oxide (CAS: 91656-71-2), dibutyl [4-(butylphenylphosphine oxide) butyl]phosphine oxide (CAS: 199284-22-5), butane-1,4-diylbis(diphenylphosphine oxide) (CAS: 4151 -27-3), 4-dimethylphosphino-1-diphenylphosphino-propane (CAS: 89807-21-6), 1,2-bis(diphenylphosphino)ethane (CAS: 4141-50-8), 4-dimethylphosphino-1-diphenylphosphino-propane (CAS: 89807-21-6), 4-dimethylphosphino-1-dimethylphosphino-butane (CAS: 98543-48-7) or propane-1,3-diylbis(diphenylphosphine oxide) (CAS: 16524-41-7).

[0024] The tungsten extractant provided by the present invention includes a balance of diluent by volume percentage. In the present invention, the diluent preferably includes one or more of white oil, kerosene, sulfonated kerosene, n-hexane, cyclohexane, carbon disulfide, methylene dichloride, ethylene dichloride, chloroform, carbon tetrachloride, methyl acetate, ethyl acetate, octanol, dichlorobenzene, trichlorobenzene, toluene and xylene, and more preferably one or more of kerosene, sulfonated kerosene, cyclohexane, carbon disulfide, ethylene dichloride, chloroform, dichlorobenzene, trichlorobenzene, octanol, toluene and xylene. In the present invention, the diluent is mainly used to provide a liquid environment for di-secondary amines and diphosphorus oxides, so as to facilitate the subsequent extraction of tungstate.

[0025] The invention adopts di-secondary amine, diphosphorus oxide and diluent to form an extractant. The di-secondary amine has a unique spatial structure and alkalinity. Compared with P204, the diphosphorus oxide also has a different chemical structure and properties. By utilizing the synergistic effect of the di-secondary amine and the diphosphorus oxide, the tungstate can be highly selective in the extraction process, and the tungstate containing molybdenum metal can be directly extracted, thereby purifying and separating to obtain a high-purity tungstate product. The extractant provided by the invention does not need to be pre-treated by saponification or the like, does not need to add acid or alkali, reduces the use of acid and alkali reagents, is environmentally friendly, has low requirements on equipment, is economical, and has a simple and efficient extraction process. Different extractant formulas can be selected for different tungstate molybdate systems, and the extractant is flexible and changeable. In addition, the diluent is cheap and easy to obtain, and has low cost. After stripping, the extractant can be reused, which is green and environmentally friendly, greatly reduces the production and use costs of the tungsten extractant, improves the market competitiveness of the tungsten extractant, and is conducive to large-scale industrial promotion.

[0026] The present invention also provides a method for preparing the tungsten extractant described in the above technical solution, comprising: mixing di-secondary amine, diphosphorus oxide and a diluent to obtain the tungsten extractant.

[0027] The present invention has no particular limitation on the specific operation of the mixing, as long as the di-secondary amine, diphosphorus oxide and diluent can be mixed uniformly.

[0028] The preparation method provided by the invention is simple, does not require special equipment, and is conducive to its industrial large-scale promotion.

[0029] The present invention also provides a method for extracting and separating tungsten, using a tungsten extractant to perform countercurrent extraction on an extract, and then performing back extraction to obtain high-purity tungstate; the tungsten extractant is the tungsten extractant described in the above technical solution or the tungsten extractant prepared by the preparation method described in the above technical solution.

[0030] In the present invention, the liquid to be extracted is a mixed solution of tungstate and molybdate; the tungstate is preferably a soluble tungstate, more preferably sodium tungstate; the molybdate is preferably a soluble molybdate, more preferably sodium molybdate; the concentration of tungsten element in the mixed solution is preferably 5-300 g / L, and the concentration of molybdenum element is preferably 0.1-30 g / L.

[0031] As an embodiment of the present invention, the concentration of tungsten element in the mixed solution can be 5g / L, 10g / L, 20g / L, 30g / L, 50g / L, 80g / L, 100g / L, 150g / L, 200g / L, 250g / L or 300g / L; the concentration of molybdenum element in the mixed solution can be 0.1g / L, 1g / L, 2g / L, 3g / L, 5g / L, 10g / L, 15g / L, 20g / L, 25g / L or 30g / L.

[0032] In the present invention, the volume ratio of the tungsten extractant to the liquid to be extracted is preferably 1:(1-10), more preferably 1:(1-5). The present invention can ensure that the tungsten extractant extracts the tungsten element in the liquid to be extracted by controlling the concentration of the tungsten extractant and the liquid to be extracted and the volume ratio of the two.

[0033] As an embodiment of the present invention, the volume ratio of the tungsten extractant to the liquid to be extracted can be 1:2, 1:3 or 1:4.

[0034] In the present invention, the countercurrent extraction is preferably carried out in a mixing and settling tank, an extraction tower or a centrifuge. The present invention has no particular limitation on the specific model and source of the mixing and settling tank, the extraction tower or the centrifuge, and a commercially available mixing and settling tank, the extraction tower or the centrifuge well known to those skilled in the art can be used.

[0035] In the present invention, the number of countercurrent extraction stages is preferably 1 to 10; the temperature of the countercurrent extraction is preferably 10 to 70° C. The present invention uses countercurrent extraction to extract tungstate solution, which can improve the extraction rate of tungsten; and the extraction rate of tungsten can be further improved by controlling the number of stages and temperature of countercurrent extraction.

[0036] As an embodiment of the present invention, the level of the countercurrent extraction can be 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10; the temperature of the countercurrent extraction can be 10°C, 15°C, 20°C, 25°C, 30°C, 35°C, 40°C, 45°C, 50°C, 55°C, 60°C, 65°C or 70°C; the time of the countercurrent extraction can be 1min, 3min, 5min, 8min, 10min, 12min, 15min, 18min, 20min, 25min, 30min, 35min or 40min.

[0037] In the present invention, the stripping agent used for the stripping preferably includes one or more of water, ammonium carbonate solution, ammonium bicarbonate solution, ammonia solution, hydroxylamine solution, sodium carbonate solution, sodium bicarbonate solution, sodium hydroxide solution and potassium hydroxide solution. The present invention has no special limitation on the concentration of the ammonium carbonate solution, ammonium bicarbonate solution, ammonia solution, hydroxylamine solution, sodium carbonate solution, sodium bicarbonate solution, sodium hydroxide solution and potassium hydroxide solution. It can be determined according to the technical common sense of those skilled in the art that tungstate can be stripped out of the extractant. As an embodiment of the present invention, the mass concentration of the ammonium carbonate solution, ammonium bicarbonate solution, ammonia solution, hydroxylamine solution, sodium carbonate solution, sodium bicarbonate solution, sodium hydroxide solution and potassium hydroxide solution can be 5%, 10%, 15%, 20%, 25%, 30%, 35% or 40%.

[0038] In the present invention, the number of stages of the stripping is preferably 1 to 5; the temperature of the stripping is preferably 15 to 80° C. The present invention has no special limitation on the stripping time, which can be determined according to the technical common sense of those skilled in the art as long as the tungstate can be stripped from the extractant. The present invention can improve the stripping efficiency by controlling the stripping temperature.

[0039] As an embodiment of the present invention, the number of stripping stages may be 1, 2, 3, 4 or 5; the stripping temperature may 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, 75°C or 80°C; the stripping time may be 1 min, 2 min, 3 min, 4 min, 5 min, 6 min, 7 min, 8 min, 9 min or 10 min.

[0040] In the present invention, the tungsten extractant after stripping is preferably continuously recycled. After stripping, the tungsten extractant provided by the present invention contains very few impurities and can be continuously used for countercurrent extraction of the extract to be extracted, thereby reducing production costs.

[0041] The method for extracting and separating tungsten provided by the present invention has a simple extraction process, which only has two processes, namely, extraction and stripping. The equipment used is conventional equipment, and the extraction conditions are simple, which can be at room temperature or appropriately heated. The extractant does not need to be pretreated by saponification, thereby reducing the use of reagents such as acids and alkalis, having low requirements on equipment and good economy.

[0042] The technical solutions in the present invention will be described clearly and completely below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0043] Example 1

[0044] A tungsten extractant, which is composed of 1% of di-secondary amine, 10% of diphosphorus oxide and the balance of diluent, by volume percentage;

[0045] The di-secondary amine is N,N-diphenylethylenediamine (CAS: 150-61-8), the diphosphorus oxide is [4-(diphenylphosphine oxide)butyl]ethylphenylphosphine oxide (CAS: 91656-71-2), and the diluent is sulfonated kerosene;

[0046] The preparation method of the tungsten extractant is as follows: di-secondary amine, diphosphorus oxide and a diluent are mixed at room temperature and then stirred evenly to obtain the tungsten extractant.

[0047] Application Example 1

[0048] A method for extracting and separating tungsten, in a centrifugal extractor, using the tungsten extractant of Example 1 to perform countercurrent extraction on an extract, and then performing stripping to obtain high-purity tungstate;

[0049] The liquid to be extracted is a mixed solution of sodium tungstate and sodium molybdate; the concentration of tungsten in the mixed solution is 10 g / L, and the concentration of molybdenum is 2 g / L;

[0050] The volume ratio of the tungsten extractant to the liquid to be extracted is 1:1:

[0051] The countercurrent extraction stage is 4, the countercurrent extraction temperature is 20°C, and the countercurrent extraction time is 9 minutes;

[0052] The stripping agent used in the stripping is water, the stripping level is 1, the stripping temperature is 20° C., the stripping time is 3 minutes, and the tungsten extractant after stripping is continuously recycled.

[0053] Example 2

[0054] A tungsten extractant, which is composed of 5% of di-secondary amine, 20% of diphosphorus oxide and the balance of diluent, by volume percentage;

[0055] The di-secondary amine is N,N-dipentylethylenediamine (CAS: 88619-07-2), the diphosphorus oxide is dibutyl [4-(butylphenylphosphine oxide) butyl]phosphine oxide (CAS: 199284-22-5), and the diluent is xylene;

[0056] The preparation method of the tungsten extractant is as follows: di-secondary amine, diphosphorus oxide and a diluent are mixed at room temperature and then stirred evenly to obtain the tungsten extractant.

[0057] Application Example 2

[0058] A method for extracting and separating tungsten, in a centrifugal extractor, using the tungsten extractant of Example 2 to perform countercurrent extraction on an extract, and then performing stripping to obtain high-purity tungstate;

[0059] The liquid to be extracted is a mixed solution of sodium tungstate and sodium molybdate; the concentration of tungsten in the mixed solution is 30 g / L, and the concentration of molybdenum is 3 g / L;

[0060] The volume ratio of the tungsten extractant to the liquid to be extracted is 2:1:

[0061] The countercurrent extraction stage is 5, the countercurrent extraction temperature is 25°C, and the countercurrent extraction time is 10 min;

[0062] The stripping agent used in the stripping is ammonium carbonate solution, the mass concentration of the ammonium carbonate solution is 25%, the stripping level is 2, the stripping temperature is 30° C., the stripping time is 2 minutes, and the tungsten extractant after stripping is continuously recycled.

[0063] Example 3

[0064] A tungsten extractant, which is composed of 15% of di-secondary amine, 25% of diphosphorus oxide and the balance of diluent, by volume percentage;

[0065] The di-secondary amine is N,N-dihexylethylenediamine (CAS: 57413-98-6), the diphosphorus oxide is butane-1,4-diylbis(diphenylphosphine oxide) (CAS: 4151-27-3), and the diluent is carbon disulfide;

[0066] The preparation method of the tungsten extractant is as follows: di-secondary amine, diphosphorus oxide and a diluent are mixed at room temperature and then stirred evenly to obtain the tungsten extractant.

[0067] Application Example 3

[0068] A method for extracting and separating tungsten, in a centrifugal extractor, using the tungsten extractant of Example 3 to perform countercurrent extraction on an extract, and then performing stripping to obtain high-purity tungstate;

[0069] The liquid to be extracted is a mixed solution of sodium tungstate and sodium molybdate; the concentration of tungsten in the mixed solution is 70 g / L, and the concentration of molybdenum is 1 g / L;

[0070] The volume ratio of the tungsten extractant to the liquid to be extracted is 3:1:

[0071] The countercurrent extraction stage is 7, the countercurrent extraction temperature is 35°C, and the countercurrent extraction time is 10 min;

[0072] The stripping agent used in the stripping is ammonia water, the mass concentration of ammonia water is 20%, the stripping level is 1, the stripping temperature is 45° C., the stripping time is 2 minutes, and the tungsten extractant after stripping is continuously recycled.

[0073] Example 4

[0074] A tungsten extractant, which is composed of 20% of di-secondary amine, 40% of diphosphorus oxide and the balance of diluent, by volume percentage;

[0075] The di-secondary amine is 1,2-bis(cyclohexylamino)ethane (CAS: 811-017-5), the diphosphorus oxide is 4-dimethylphosphine-1-diphenylphosphine oxide (CAS: 89807-21-6), and the diluent is chloroform;

[0076] The preparation method of the tungsten extractant is as follows: di-secondary amine, diphosphorus oxide and a diluent are mixed at room temperature and then stirred evenly to obtain the tungsten extractant.

[0077] Application Example 4

[0078] A method for extracting and separating tungsten, in a centrifugal extractor, using the tungsten extractant of Example 4 to perform countercurrent extraction on an extract, and then performing back extraction to obtain high-purity tungstate;

[0079] The liquid to be extracted is a mixed solution of sodium tungstate and sodium molybdate; the concentration of tungsten in the mixed solution is 75 g / L, and the concentration of molybdenum is 13 g / L;

[0080] The volume ratio of the tungsten extractant to the liquid to be extracted is 2:1:

[0081] The countercurrent extraction stage is 4, the countercurrent extraction temperature is 29°C, and the countercurrent extraction time is 6 minutes;

[0082] The stripping agent used in the stripping is hydroxylamine solution, the mass concentration of the hydroxylamine solution is 30%, the stripping level is 1, the stripping temperature is 33° C., the stripping time is 1 minute, and the tungsten extractant after stripping is continuously recycled.

[0083] Example 5

[0084] A tungsten extractant, which is composed of 30% of di-secondary amine, 50% of diphosphorus oxide and the balance of diluent, by volume percentage;

[0085] The di-secondary amine is N,N-diphenylmethanediamine (CAS: 622-14-0), the diphosphorus oxide is 1,2-bis(diphenylphosphino)ethane (CAS: 4141-50-8), and the diluent is cyclohexane;

[0086] The preparation method of the tungsten extractant is as follows: di-secondary amine, diphosphorus oxide and a diluent are mixed at room temperature and then stirred evenly to obtain the tungsten extractant.

[0087] Application Example 5

[0088] A method for extracting and separating tungsten, in an extraction tower, using the tungsten extractant of Example 5 to perform countercurrent extraction on an extract, and then performing stripping to obtain high-purity tungstate;

[0089] The liquid to be extracted is a mixed solution of sodium tungstate and sodium molybdate; the concentration of tungsten in the mixed solution is 55 g / L, and the concentration of molybdenum is 4 g / L;

[0090] The volume ratio of the tungsten extractant to the liquid to be extracted is 2:1:

[0091] The countercurrent extraction stage is 3, the countercurrent extraction temperature is 60°C, and the countercurrent extraction time is 10 min;

[0092] The stripping agent used in the stripping is sodium hydroxide solution, the mass concentration of the sodium hydroxide solution is 15%, the stripping level is 1, the stripping temperature is 65° C., the stripping time is 1 minute, and the tungsten extractant after stripping is continuously recycled.

[0093] Example 6

[0094] A tungsten extractant, which is composed of 25% of di-secondary amine, 46% of diphosphorus oxide and the balance of diluent, by volume percentage;

[0095] The di-secondary amine is N,N-diphenylbutanediamine (CAS: 104-69-8), the diphosphorus oxide is 4-dimethylphosphine-1-diphenylphosphine oxide (CAS: 89807-21-6), and the diluent is a mixture of chloroform and trichlorobenzene in a volume ratio of 1:1;

[0096] The preparation method of the tungsten extractant is as follows: di-secondary amine, diphosphorus oxide and a diluent are mixed at room temperature and then stirred evenly to obtain the tungsten extractant.

[0097] Application Example 6

[0098] A method for extracting and separating tungsten, in an extraction tower, using the tungsten extractant of Example 6 to perform countercurrent extraction on an extract, and then performing stripping to obtain high-purity tungstate;

[0099] The liquid to be extracted is a mixed solution of sodium tungstate and sodium molybdate; the concentration of tungsten element in the mixed solution is 100 g / L, and the concentration of molybdenum element is 3 g / L;

[0100] The volume ratio of the tungsten extractant to the liquid to be extracted is 5:1:

[0101] The countercurrent extraction stage is 3, the countercurrent extraction temperature is 48°C, and the countercurrent extraction time is 20 min;

[0102] The stripping agent used in the stripping is potassium hydroxide solution, the mass concentration of the potassium hydroxide solution is 25%, the stripping level is 1, the stripping temperature is 50° C., the stripping time is 5 minutes, and the tungsten extractant after stripping is continuously recycled.

[0103] Example 7

[0104] A tungsten extractant, which is composed of 45% of di-secondary amine, 50% of diphosphorus oxide and the balance of diluent, by volume percentage;

[0105] The di-secondary amine is N,N-dibutylethylenediamine (CAS: 4013-95-0), the diphosphorus oxide is 4-dimethylphosphine-1-dimethylphosphine butane (CAS: 98543-48-7), and the diluent is a mixture of sulfonated kerosene and ethylene dichloride in a volume ratio of 2:1;

[0106] The preparation method of the tungsten extractant is as follows: di-secondary amine, diphosphorus oxide and a diluent are mixed at room temperature and then stirred evenly to obtain the tungsten extractant.

[0107] Application Example 7

[0108] A method for extracting and separating tungsten, in a mixing and settling tank, using the tungsten extractant of Example 7 to perform countercurrent extraction on the extract, and then performing back extraction to obtain high-purity tungstate;

[0109] The liquid to be extracted is a mixed solution of sodium tungstate and sodium molybdate; the concentration of tungsten element in the mixed solution is 240g / L, and the concentration of molybdenum element is 25g / L;

[0110] The volume ratio of the tungsten extractant to the liquid to be extracted is 1:1:

[0111] The countercurrent extraction stage is 6, the countercurrent extraction temperature is 25°C, and the countercurrent extraction time is 15 minutes;

[0112] The stripping agent used in the stripping is sodium bicarbonate solution, the mass concentration of the sodium bicarbonate solution is 20%, the stripping level is 3, the stripping temperature is 35° C., the stripping time is 3 minutes, and the tungsten extractant after stripping is continuously recycled.

[0113] Example 8

[0114] A tungsten extractant, which is composed of 40% of di-secondary amine, 45% of diphosphorus oxide and the balance of diluent, by volume percentage;

[0115] The di-secondary amine is N,N-diphenylbutanediamine (CAS: 13170-61-1), the diphosphorus oxide is propane-1,3-diylbis(diphenylphosphine oxide) (CAS: 16524-41-7), and the diluent is a mixture of toluene and carbon tetrachloride in a volume ratio of 2:1;

[0116] The preparation method of the tungsten extractant is as follows: di-secondary amine, diphosphorus oxide and a diluent are mixed at room temperature and then stirred evenly to obtain the tungsten extractant.

[0117] Application Example 8

[0118] A method for extracting and separating tungsten, in a mixing and settling tank, using the tungsten extractant of Example 8 to perform countercurrent extraction on the extract, and then performing back extraction to obtain high-purity tungstate;

[0119] The liquid to be extracted is a mixed solution of sodium tungstate and sodium molybdate; the concentration of tungsten in the mixed solution is 180 g / L, and the concentration of molybdenum is 13 g / L;

[0120] The volume ratio of the tungsten extractant to the liquid to be extracted is 2:1:

[0121] The countercurrent extraction stage is 6, the countercurrent extraction temperature is 25°C, and the countercurrent extraction time is 35min;

[0122] The stripping agent used in the stripping is ammonium carbonate solution, the mass concentration of the ammonium carbonate solution is 25%, the stripping level is 2, the stripping temperature is 30° C., the stripping time is 10 minutes, and the tungsten extractant after stripping is continuously recycled.

[0123] The extraction rate of sodium tungstate and the purity of sodium tungstate obtained in Application Examples 1 to 8 are shown in Table 1:

[0124] Table 1 Extraction rate of sodium tungstate obtained in application examples 1 to 8 and purity of sodium tungstate

[0125] Example Extraction rate of sodium tungstate / % Purity of Sodium Tungstate / % Application Example 1 85 88 Application Example 2 97 98 Application Example 3 99 99 Application Example 4 88 89 Application Example 5 91 90 Application Example 6 91 93 Application Example 7 89 95 Application Example 8 92 99

[0126] Among them, the purity test uses an ICP-MS instrument to measure the content of sodium tungstate and sodium molybdate in the solution to obtain the purity of sodium tungstate.

[0127] It can be seen from Table 1 that after the mixed solution of sodium tungstate and sodium molybdate is extracted by the tungsten extractant provided by the present invention, the extraction rate of sodium tungstate is ≥85%, and can reach 99% at the highest. Sodium tungstate has high purity and few impurities, and the purity is ≥88%, and can reach 99% at the highest. This shows that the tungsten extractant provided by the present invention can be used for the extraction of tungsten element and can achieve a good extraction effect.

[0128] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A tungsten extractant, comprising the following components by volume percentage: 1-45% of di-secondary amine, 10-50% of diphosphorus oxide and the remainder of diluent.

2. The tungsten extractant according to claim 1, characterized in that: The structure of the di-secondary amine is The n is 1 to 20; the R 1 and R 2 Independently C1~C 30 Alkyl, C3~C8 cycloalkyl and C5~C 15 Any of the aromatic groups.

3. The tungsten extractant according to claim 1, characterized in that: The structure of the diphosphorus oxide is The n is 1 to 20; the R 3 , R 4 , R 5 and R 6 Independently C1~C 30 Alkyl, C3~C 10 Cycloalkyl and C5~C 19 Any of the aromatic groups.

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

5. The method for preparing the tungsten extractant according to any one of claims 1 to 4, comprising: The di-secondary amine, di-phosphorus oxide and a diluent are mixed to obtain a tungsten extractant.

6. A method for extracting and separating tungsten, characterized in that: The extract is subjected to countercurrent extraction using a tungsten extractant, and then stripped to obtain high-purity tungstate; the tungsten extractant is the tungsten extractant according to any one of claims 1 to 4 or the tungsten extractant prepared by the preparation method according to claim 5.

7. The method according to claim 6, characterized in that The volume ratio of the tungsten extractant to the liquid to be extracted is 1:(1-10).

8. The method according to claim 6, characterized in that The number of the countercurrent extraction stages is 1 to 10; the temperature of the countercurrent extraction is 10 to 70°C.

9. The method according to claim 6, characterized in that The stripping agent used in the stripping includes one or more of water, ammonium carbonate solution, ammonium bicarbonate solution, ammonia solution, hydroxylamine solution, sodium carbonate solution, sodium bicarbonate solution, sodium hydroxide solution and potassium hydroxide solution.

10. The method according to claim 6, characterized in that The number of the stripping stages is 1 to 5; the stripping temperature is 15 to 80°C.

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