An extractant and its application in lithium rubidium cesium extraction

Abstract

The present invention relates to an extractant and its application in the extraction of lithium, rubidium and cesium. The extractant includes a compound with a structure as shown in Formula I or Formula II; the application includes the following steps: (1) the extractant and a diluent are mixed to form an extraction system, and the system is mixed with a feed liquid containing alkali metals under alkaline conditions for extraction; (2) the organic phase obtained after extraction is mixed with a stripping solution, and stripped to an aqueous phase; (3) the aqueous phase obtained is precipitated or heated to separate and obtain an alkali metal-containing compound or enrichment. The extractant of the present invention has simple synthesis steps, a wide range of synthetic raw materials, low water solubility and strong stability, which can reduce environmental pollution and reduce costs; it can be used in the extraction of lithium, rubidium and cesium to efficiently extract valuable metals Li, Rb and Cs, and can be used with a large amount of Na + , K + or NH4 + The impurities are separated, the recovery rate of valuable metals Li, Rb and Cs is high, the product purity is high, and it has good industrial application prospects.

Description

Technical Field

[0001] The invention relates to the technical field of chemical separation, and in particular to an extractant and application thereof in the extraction of lithium, rubidium and cesium. Background Art

[0002] Lithium, rubidium and cesium are precious rare elements belonging to the first main group elements. They often coexist with sodium and potassium in ores and brines. With the rapid development of batteries and advanced materials, the consumption of Li, Rb and Cs in production has increased rapidly, with Li increasing from about 150,000 tons (in terms of lithium carbonate) in 2011 to about 500,000 tons now; and the total consumption of Rb and Cs has also increased from less than 1,000 tons (in terms of metal salts) to nearly 10,000 tons. The high-valent metal ions produced during the extraction of Li, Rb and Cs, especially the divalent metal ions, can be separated and removed by precipitation, membrane separation and other technologies, but a large amount of monovalent ions Na + and K + For example, after the lithium mica ore salt is roasted and soaked in water, a liquid containing Li, Na, K, Rb and Cs is obtained; the carbonate salt lakes in Tibet, my country, which are rich in reserves, contain valuable resources of Li, Rb, Cs and a large amount of Na + and K + Impurities; During the recycling process of secondary ternary battery materials, after oxidation leaching, a solution containing Ni, Co, Mn and Li is obtained. After extracting Ni, Co and Mn, a solution containing Li remains. If ammonia water is used for neutralization during the extraction process, the solution will also contain a large amount of NH4 + Therefore, in order to obtain high-purity Li, Rb and Cs products, it is necessary to realize the reaction of Li, Rb and Cs with other monovalent metal ions Na + , K + or NH4 + Efficient separation is of great significance.

[0003] At present, many documents have reported the use of solvent extraction to recover Li from solutions containing alkali metal ions such as Na, K, Li, Rb or Cs. CN107779612A discloses a process for extracting lithium from alkaline brine, which uses a composite synergistic extraction system composed of trifluoromethyl diketone compounds and neutral phosphorus compounds to extract lithium from alkaline lithium-containing brine, and realizes the enrichment of lithium in the stripping solution and the recycling of the organic phase through the extraction-washing-stripping-regeneration process. However, the composition of the synergistic system of this method is complex, in which the fluorine-containing extractant is easy to harm the environment, the organic phase needs to consume alkali for regeneration, and the process flow is long. CN111057848A discloses a method for extracting lithium from a lithium-containing solution using a solvent extraction method, using a composite synergistic extraction system composed of dodecylphenyl-methyl-β-diketone and trioctyl / hexyl phosphine oxide to separate lithium from a lithium-containing and monovalent metal impurity solution, and the high-purity lithium-containing solution obtained by stripping can be further prepared into different types of lithium salt products. This method has a short process flow and reduces environmental pollution, but the composite extraction system used in this method is also very complex. CN110656239B discloses a method for extracting lithium by extraction-stripping separation and purification, which uses a composite extraction system composed of ketone chelates and neutral phosphorus compounds to separate lithium and monovalent impurities at a higher pH value, and then uses gas-liquid-liquid three-phase continuous stripping to obtain a lithium product after heat treatment of the stripping solution. The above methods all use a complex composite extraction system. Although it can achieve effective separation of Li and monovalent impurities Na and K, it cannot comprehensively utilize valuable metals such as Rb and Cs in alkaline solutions, resulting in a waste of resources.

[0004] CN107460344A discloses a method for extracting rubidium and cesium from salt lake brine. The method uses t-BAMBP organic phase saponified with an alkaline solution to extract Cs and Rb from the salt lake brine. After the loaded organic phase is reversed, a stripping solution containing Cs and Rb and a blank organic phase are obtained. Although the method can separate Rb, Cs and impurity K in the brine, it cannot simultaneously recover Li resources in the brine.

[0005] In view of the problems in the above literature, achieving high recovery rate of Li, Rb and Cs, high product purity, short extraction process, low cost and easy industrial production are the problems that need to be solved urgently. Therefore, it is necessary to develop an extraction agent and apply it to extracting Li, Rb and Cs from raw materials containing a large amount of Na + , K + or NH4 + It is very necessary to extract Li, Rb and Cs with high selectivity from the impurity solution. Summary of the invention

[0006] In view of the problems existing in the prior art, the present invention provides an extractant and its application in the extraction of lithium, rubidium and cesium, wherein the extractant can realize the efficient extraction of Li, Rb and Cs, and can react with the monovalent impurity Na+ , K + or NH4 + separate.

[0007] In order to achieve the above technical effects, the present invention adopts the following technical solutions:

[0008] The present invention provides an extractant, which includes an extractant A as shown in formula I or an extractant B as shown in formula II:

[0009]

[0010] Wherein, R1 in the formula I is a straight chain or branched alkyl group of C4-C12 (for example, C4, C5, C6, C7, C8, C9, C10, C11 or C12), and R2 is n-octyl or isooctyl; R3 in the formula II is a straight chain or branched alkyl group of C8-C12 (for example, C8, C9, C10, C11 or C12), and R4 is n-octyl or isooctyl.

[0011] In the present invention, the extractant A can be any one of (4-(1-(5-butyl-2-hydroxyphenyl)ethyl)phenyl)dioctylphosphine oxide, (4-(1-(5-pentyl-2-hydroxyphenyl)ethyl)phenyl)dioctylphosphine oxide, (4-(1-(5-octyl-2-hydroxyphenyl)ethyl)phenyl)diisooctylphosphine oxide, (4-(1-(5-butyl-2-hydroxyphenyl)ethyl)phenyl)diisooctylphosphine oxide or (4-(1-(5-heptyl-2-hydroxyphenyl)ethyl)phenyl)dioctylphosphine oxide, but is not limited to the listed compounds, and other unlisted compounds within the scope of R1 and R2 are also applicable.

[0012] In the present invention, the extractant B can be any one of 4-dioctylphosphoryl-1-(4-octylphenyl)butane-1,3-dione, 4-dioctylphosphoryl-1-(4-nonylphenyl)butane-1,3-dione, 4-diisooctylphosphoryl-1-(4-octylphenyl)butane-1,3-dione or 4-diisooctylphosphoryl-1-(4-decylphenyl)butane-1,3-dione, but is not limited to the listed compounds. Other unlisted compounds within the scope of R3 and R4 are also applicable.

[0013] Preferably, the synthesis method of the extractant A comprises: 4-chloromethylstyrene and alkylphenol are subjected to an addition reaction to obtain an alkyl-2-(1-(4-(chloromethyl)phenyl)ethyl)phenol intermediate, sodium hypophosphite and unsaturated olefin are subjected to an addition-reduction reaction to obtain a dialkylphosphine oxide intermediate, and the two intermediates are subjected to an addition-hydrolysis reaction to obtain the extractant A.

[0014] Preferably, the synthesis method of the extractant B comprises: a carbonyl compound containing a benzene ring and a halogenated carboxylic acid ester undergo a Claisen condensation reaction under base catalysis to obtain a β-diketone intermediate, sodium hypophosphite and an unsaturated olefin undergo an addition-reduction reaction to obtain a dialkylphosphine oxide intermediate, and the two intermediates undergo an addition-hydrolysis reaction to obtain the extractant B.

[0015] In the present invention, the synthetic raw materials of the extractant are widely available, the synthetic steps are simple, the extractant has low water solubility and strong stability, so that the subsequent extraction process is stable and environmental pollution is reduced. Because both the extractant A and the extractant B have -OH and P=O groups (the carbonyl group in B has keto-enol tautomerism equilibrium), they can react with Li + After coordination, a stable neutral chelate is formed, so the two extractants can significantly improve the Li + extraction rate; at the same time, since the benzene ring connected to the phenolic hydroxyl group of extractant A has a strong electron-withdrawing effect, it also has a strong binding ability with Rb and Cs, thereby improving the extraction rate of Rb and Cs.

[0016] The present invention also provides an application of the aforementioned extractant in the extraction of lithium, rubidium and cesium, the application comprising the following steps:

[0017] (1) mixing the extractant A or the extractant B with a diluent to form an extraction system, and mixing it with a feed liquid containing an alkali metal under alkaline conditions to perform extraction;

[0018] (2) mixing the organic phase obtained after extraction in step (1) with a stripping solution, and stripping to obtain an aqueous phase;

[0019] (3) The aqueous phase obtained in step (2) is precipitated or heated to separate the alkali metal-containing compound or enriched product.

[0020] As a preferred technical solution of the present invention, the concentration of the extractant A in the extraction system of step (1) is 0.2-1.0 mol / L, for example, it can be 0.2 mol / L, 0.4 mol / L, 0.6 mol / L, 0.8 mol / L or 1.0 mol / L, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0021] Preferably, the concentration of the extractant B in the extraction system of step (1) is 0.2-1.0 mol / L, for example, 0.2 mol / L, 0.4 mol / L, 0.6 mol / L, 0.8 mol / L or 1.0 mol / L, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0022] As a preferred technical solution of the present invention, the diluent in step (1) includes any one of hydrogenated kerosene, sulfonated kerosene, aliphatic hydrocarbons or aromatic hydrocarbons, or a combination of at least two of them. Typical but non-limiting examples of the combination include: a combination of hydrogenated kerosene and sulfonated kerosene, a combination of hydrogenated kerosene and aliphatic hydrocarbons, or a combination of aliphatic hydrocarbons and aromatic hydrocarbons, etc.

[0023] Preferably, the feed solution in step (1) comprises any one of a lithium ore leachate, a lithium precipitation mother liquor, a lithium battery waste leachate, a salt lake brine or a solution for secondary resource recovery, or a combination of at least two of them. Typical but non-limiting examples of the combination include: a combination of a lithium ore leachate and a lithium precipitation mother liquor, a combination of a lithium precipitation mother liquor and a lithium battery waste leachate, or a combination of a lithium precipitation mother liquor and a salt lake brine, etc.

[0024] Preferably, the alkaline condition in step (1) is to adjust the pH to 8-14, for example, it can be 8, 9, 10, 11.5, 12.5, 13 or 14, but is not limited to the listed values. Other values ​​not listed in the numerical range are also applicable, preferably 11.5-12.5.

[0025] Preferably, the regulator used to adjust the pH includes any one of sodium hydroxide, potassium hydroxide or an aqueous ammonia solution, or a combination of at least two of them. Typical but non-limiting examples of the combination include: a combination of sodium hydroxide and potassium hydroxide, a combination of sodium hydroxide and an aqueous ammonia solution, or a combination of potassium hydroxide and an aqueous ammonia solution.

[0026] Preferably, the alkali metal in the slurry of step (1) comprises any one of Li, Rb or Cs or a combination of at least two of them. Typical but non-limiting examples of the combination include: a combination of Li and Rb, a combination of Li and Cs, or a combination of Li, Rb and Cs.

[0027] Preferably, the concentration of Li, Rb or Cs is independently 0.1-5 g / L, for example, 0.1 g / L, 0.5 g / L, 1 g / L, 2 g / L, 3 g / L, 4 g / L or 5 g / L, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0028] Preferably, the feed solution in step (1) also includes Na + , K + or NH4 + Any one or a combination of at least two of the above, typical but non-limiting examples of the above combinations are: Na + and K + Combination of Na + and NH4 + Combination or K + and NH4 + combinations of etc.

[0029] Preferably, the Na + , K + and / or NH4 + The total concentration is 10-200 g / L, for example, it can be 10 g / L, 50 g / L, 90 g / L, 130 g / L, 170 g / L or 200 g / L, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0030] As a preferred technical solution of the present invention, the stripping solution in step (2) is an acidic solution or a mixed solution of a weakly acidic gas and water.

[0031] Preferably, the acidic solution comprises any one of hydrochloric acid solution, sulfuric acid solution, phosphoric acid solution, citric acid solution or malic acid solution, or a combination of at least two of them. Typical but non-limiting examples of the combination include: a combination of hydrochloric acid solution and sulfuric acid solution, a combination of sulfuric acid solution and phosphoric acid solution, or a combination of citric acid solution and malic acid solution, etc.

[0032] Preferably, the weakly acidic gas includes CO2 and / or SO2.

[0033] Preferably, the total concentration of alkali metal ions contained in the aqueous phase in step (2) is greater than 6 g / L, for example, it can be 7 g / L, 8 g / L, 9 g / L, 10 g / L or 11 g / L, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0034] Preferably, the pH of the aqueous phase in step (2) is 3-7.5, for example, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7 or 7.5, etc., but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0035] As a preferred technical solution of the present invention, the precipitation treatment in step (3) is to add a precipitant.

[0036] Preferably, the precipitant is sodium carbonate and / or sodium carbonate solution.

[0037] Preferably, the temperature of the heating treatment in step (3) is 80-110°C, for example, it can be 80°C, 85°C, 90°C, 95°C, 100°C, 105°C or 110°C, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0038] Preferably, the heating treatment time in step (3) is 0.5-2 h, for example, 0.5 h, 1 h, 1.5 h or 2 h, etc., but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0039] Preferably, the separation method in step (3) comprises any one of filtration, suction filtration or centrifugation, or a combination of at least two of them. Typical but non-limiting examples of the combination include: a combination of filtration and suction filtration, a combination of filtration and centrifugation, or a combination of suction filtration and centrifugation, etc.

[0040] Preferably, the alkali metal-containing compound or enriched product in step (3) is Li or chloride, sulfate or carbonate of Li, Rb and Cs. It is easier to obtain enriched products of Li, Rb and Cs by using extractant A, and it is easier to obtain Li compounds by using extractant B.

[0041] As a preferred technical solution of the present invention, the application of the extractant in the extraction of lithium, rubidium and cesium specifically comprises the following steps:

[0042] (1) 0.2-1.0 mol / L of extractant A or 0.2-1.0 mol / L of extractant B is mixed with a diluent to form an extraction system, and the extraction system is mixed with an alkali metal containing Li, Rb or Cs at a concentration of 0.1-5 g / L and a total concentration of Na at a concentration of 10-200 g / L at a pH of 8-14. + , K + and / or NH4 + The feed liquid is mixed for extraction;

[0043] (2) mixing the organic phase obtained after the extraction in step (1) with an acidic solution or mixing the organic phase with a mixed solution of a weakly acidic gas and water, and stripping to an aqueous phase, wherein the total concentration of alkali metal ions in the aqueous phase is greater than 6 g / L, and the pH of the aqueous phase is 3-7.5;

[0044] (3) The aqueous phase obtained in step (2) is subjected to precipitation treatment or heated at 80-110° C. for 0.5-2 h to separate the chloride, sulfate or carbonate containing Li or Li, Rb and Cs.

[0045] Compared with the prior art, the present invention has the following beneficial effects:

[0046] (1) The extractant of the present invention can efficiently extract valuable metals such as lithium, rubidium and cesium, and can react with a large amount of Na + , K + or NH4 + The impurities are separated, and the obtained product has high purity. The stripping rates of Li, Rb and Cs are all greater than 95%, and the recovery rates of Li, Rb and Cs are all greater than 90%;

[0047] (2) The extractant of the present invention has simple synthesis steps, a wide range of synthetic raw materials, low water solubility, strong stability, low oil content in the raffinate, and reduced environmental pollution;

[0048] (3) The extraction process used in the present invention is simple, reduces production costs, is highly efficient and environmentally friendly, and has good industrial application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 The extractant A is Li + The extraction process;

[0050] Figure 2 The extractant B is Li + extraction process. DETAILED DESCRIPTION

[0051] The technical solution of the present invention is further described below by specific implementation methods. Those skilled in the art should understand that the preparation examples and application examples are only used to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0052] Preparation Example 1

[0053] This preparation example provides an extractant, which includes extractant A or extractant B;

[0054] The synthesis method of the extractant A comprises:

[0055] (1) 152.6 g of 4-chloromethylstyrene, 75 g of p-tert-butylphenol, and 10 g of concentrated phosphoric acid were added to a 500 mL round-bottom flask in sequence and reacted at 150° C. for 6 h. After the reaction, the concentrated phosphoric acid was washed off with sodium carbonate, and low-boiling substances were removed by reduced pressure distillation to obtain 145 g of 4-(tert-butyl)-2-(1-(4-(chloromethyl)phenyl)ethyl)phenol, with a yield of 91%.

[0056] (2) 280 g of 1-octene, 88 g of sodium hypophosphite, 3.6 g of benzoyl peroxide (BPO) and 100 g of acetic acid were added to a 1 L round-bottom flask in sequence and stirred at 135°C for 4 h. After the reaction was completed, the solid was filtered and the filtrate was washed twice with 1 M sulfuric acid. After separation, the organic phase was distilled under reduced pressure to remove low-boiling substances, and then 200 mL of toluene and 300 g of trichlorosilane were added. The reaction was carried out at 80°C for 4 h. After the low-boiling substances were removed by distillation under reduced pressure, 252 g of dioctylphosphine oxide was obtained with a yield of 95%.

[0057] (3) In a 500 mL round-bottom flask, 145 g of 4-(tert-butyl)-2-(1-(4-(chloromethyl)phenyl)ethyl)phenol and 126 g of dioctylphosphine oxide were added, and the mixture was reacted at 100° C. for 3 h. After cooling, 100 mL of distilled water was added, and the mixture was refluxed for 5 h to obtain 244 g of (4-(1-(5-(tert-butyl)-2-hydroxyphenyl)ethyl)phenyl)dioctylphosphine oxide with a yield of 93%.

[0058] The synthesis method of the extractant B comprises:

[0059] (1) 248 g of 4-octylacetophenone, 83.5 g of ethyl bromoacetate, 10 g of sodium ethoxide and 100 mL of DMF were added to a 500 mL round-bottom flask in sequence and stirred at 120°C for 6 h. After the reaction was completed, the organic phase was washed twice with deionized water. Low boiling substances were removed by vacuum distillation to obtain 172 g of light yellow liquid 4-bromo-1-(4-octylphenyl)butane-1,3-dione for use.

[0060] (2) In a 500 mL round-bottom flask, 145 g of 4-bromo-1-(4-octylphenyl)butane-1,3-dione and 126 g of dioctylphosphine oxide were added and reacted at 100 °C for 3 h. After cooling, 100 mL of distilled water was added and refluxed for 5 h to obtain 256 g of 4-(dioctylphosphinoyl)-1-(4-octylphenyl)butane-1,3-dione with a yield of 94%.

[0061] Preparation Example 2

[0062] This preparation example provides an extractant, which includes extractant A or extractant B;

[0063] The synthesis method of the extractant A comprises:

[0064] (1) 152.6 g of 4-chloromethylstyrene, 75 g of p-tert-butylphenol, and 10 g of concentrated phosphoric acid were added to a 500 mL round-bottom flask in sequence and reacted at 150° C. for 6 h. After the reaction, the concentrated phosphoric acid was washed off with sodium carbonate, and low-boiling substances were removed by reduced pressure distillation to obtain 145 g of 4-(tert-butyl)-2-(1-(4-(chloromethyl)phenyl)ethyl)phenol, with a yield of 91%.

[0065] (2) 280 g of 2-ethyl-1-hexene, 88 g of sodium hypophosphite, 3.6 g of benzoyl peroxide (BPO) and 100 g of acetic acid were added to a 1 L round-bottom flask in sequence and stirred at 135° C. for 4 h. After the reaction was completed, the solid was filtered and the filtrate was washed twice with 1 M sulfuric acid. After separation, the organic phase was distilled under reduced pressure to remove low-boiling substances, and then 200 mL of toluene and 300 g of trichlorosilane were added. The reaction was carried out at 80° C. for 4 h. After the low-boiling substances were removed by distillation under reduced pressure, 252 g of diisooctylphosphine oxide was obtained with a yield of 95%.

[0066] (3) In a 500 mL round-bottom flask, 145 g of 4-(tert-butyl)-2-(1-(4-(chloromethyl)phenyl)ethyl)phenol and 126 g of diisooctylphosphine oxide were added. The mixture was reacted at 100° C. for 3 h. After cooling, 100 mL of distilled water was added and the mixture was refluxed for 5 h to obtain 244 g of (4-(1-(5-(tert-butyl)-2-hydroxyphenyl)ethyl)phenyl)diisooctylphosphine oxide with a yield of 93%.

[0067] The synthesis method of the extractant B comprises:

[0068] (1) 248 g of 4-octylacetophenone, 83.5 g of ethyl bromoacetate, 10 g of sodium ethoxide and 100 mL of DMF were added to a 500 mL round-bottom flask in sequence and stirred at 120°C for 6 h. After the reaction was completed, the organic phase was washed twice with deionized water. Low boiling substances were removed by vacuum distillation to obtain 172 g of light yellow liquid 4-bromo-1-(4-octylphenyl)butane-1,3-dione for use.

[0069] (2) In a 500 mL round-bottom flask, 145 g of 4-bromo-1-(4-octylphenyl)butane-1,3-dione and 126 g of diisooctylphosphine oxide were added. The mixture was reacted at 100 °C for 3 h. After cooling, 100 mL of distilled water was added and the mixture was refluxed for 5 h to obtain 256 g of 4-(diisooctylphosphinoyl)-1-(4-octylphenyl)butane-1,3-dione with a yield of 94%.

[0070] Preparation Example 3

[0071] This preparation example provides an extractant, which includes extractant A or extractant B;

[0072] The synthesis method of the extractant A comprises:

[0073] (1) 152.6 g of 4-chloromethylstyrene, 131.2 g of p-dodecylphenol, and 12 g of concentrated phosphoric acid were added to a 500 mL round-bottom flask in sequence and reacted at 170° C. for 8 h. After the reaction, the concentrated phosphoric acid was washed off with sodium carbonate, and the excess 4-chloromethylstyrene was removed by reduced pressure distillation to obtain 200 g of 2-(1-(4-(chloromethyl)phenyl)ethyl)-4-dodecylphenol, with a yield of 96%.

[0074] (2) 280 g of 1-octene, 88 g of sodium hypophosphite, 3.6 g of benzoyl peroxide (BPO) and 100 g of acetic acid were added to a 1 L round-bottom flask in sequence and stirred at 135° C. for 4 h. After the reaction was completed, the solid was filtered and the filtrate was washed twice with 1 M sulfuric acid. After separation, the organic phase was distilled under reduced pressure to remove low-boiling substances, and then 200 mL of toluene and 300 g of trichlorosilane were added. The reaction was carried out at 80° C. for 4 h. After the low-boiling substances were removed by distillation under reduced pressure, 249 g of dioctylphosphine oxide was obtained with a yield of 94%.

[0075] (3) In a 500 mL round-bottom flask, 200 g of 2-(1-(4-(chloromethyl)phenyl)ethyl)-4-dodecylphenol and 141 g of dioctylphosphine oxide were added, and the mixture was reacted at 100° C. for 3 h. After cooling, 100 mL of distilled water was added, and the mixture was refluxed for 5 h to obtain 268.6 g of (4-(1-(5-dodecyl-2-hydroxyphenyl)ethyl)phenyl)dioctylphosphine oxide with a yield of 88%.

[0076] The synthesis method of the extractant B comprises:

[0077] (1) 246 g of 4-n-nonylacetophenone, 83.5 g of ethyl bromoacetate, 10 g of sodium ethoxide and 100 mL of DMF were added to a 500 mL round-bottom flask in sequence and stirred at 120°C for 6 h. After the reaction was completed, the organic phase was washed twice with deionized water. Low boiling substances were removed by distillation under reduced pressure to obtain 178 g of light yellow liquid 4-bromo-1-(4-n-nonylphenyl)butane-1,3-dione for use.

[0078] (2) In a 500 mL round-bottom flask, 178 g of 4-bromo-1-(4-n-nonylphenyl)butane-1,3-dione and 146 g of dioctylphosphine oxide were added. The mixture was reacted at 100 °C for 3 h. After cooling, 100 mL of distilled water was added and the mixture was refluxed for 5 h to obtain 252 g of 4-(dioctylphosphinoyl)-1-(4-n-nonylphenyl)butane-1,3-dione with a yield of 90%.

[0079] A kind of extractant A to Li + The extraction process, such as Figure 1 As shown. [Li(H2O)] + It is easy to form a stable neutral chelate with -OH and P=O in compounds containing phenolic hydroxyl groups and phosphorus oxygen functional groups, among which Li + After coordination, a stable seven-membered chelate ring is formed. Since the benzene ring connected to the phenolic hydroxyl group has a strong electron-withdrawing effect, the phenolic hydroxyl group and Li + It can be more tightly bound. At the same time, this phenolic hydroxyl group is also easier to combine with Rb and Cs to form corresponding extractants. + The organic phase is mixed with a weak acid and Li + With H + Ion exchange can achieve Li + of back extraction.

[0080] A kind of extractant B to Li + The extraction process, such as Figure 2 As shown. Compounds containing β-diketone functional groups and phosphorus oxygen functional groups have tautomeric equilibrium between the keto form and the enol form. During the extraction process, [Li(H2O)] + It is easy to form a stable neutral chelate with -OH and P=O, in which Li + After coordination, a stable seven-membered chelate ring is formed. Since the benzene ring contained in this type of compound has a strong electron-withdrawing effect, Li + The formed chelate is more stable.

[0081] Application Example 1

[0082] This application example provides an application of the extractant in the extraction of lithium, rubidium and cesium, and the application comprises the following steps:

[0083] (1) The extractant A obtained in Preparation Example 1 was mixed with hydrogenated kerosene to form an extraction system, and the pH of the extraction system was adjusted to 11.5 using sodium hydroxide. Under this condition, the extraction system was mixed with a Li concentration of 1 g / L, a Rb concentration of 0.1 g / L, a Cs concentration of 0.1 g / L, and a Na + The concentration is 10g / L, K + Concentration of 10g / L and NH4 + The lithium precipitate mother liquor with a concentration of 10 g / L is mixed for extraction;

[0084] (2) mixing the loaded organic phase containing Li, Rb and Cs obtained in step (1) with a hydrochloric acid solution for stripping, with a ratio (volume of organic phase to volume of aqueous phase) of 35:1, and obtaining an aqueous phase containing 31.9 g / L, 3.1 g / L and 3.2 g / L of Li, Rb and Cs, respectively, after stripping, with a pH value of 4, stripping rates of Li, Rb and Cs of 96%, 95% and 97%, respectively, and recoveries of Li, Rb and Cs of 91%, 90% and 92%, respectively;

[0085] (3) The aqueous phase obtained in step (2) was heated at 95° C. for 1 h, and filtered to obtain LiCl, RbCl and CsCl products with purities of 99%, 98% and 98%, respectively.

[0086] Application Example 2

[0087] This application example provides an application of the extractant in the extraction of lithium, rubidium and cesium, and the application comprises the following steps:

[0088] (1) The extractant A obtained in Preparation Example 2 was mixed with hydrogenated kerosene to form an extraction system, and the pH of the extraction system was adjusted to 12.5 using sodium hydroxide. Under this condition, the extraction system was mixed with a Li concentration of 0.5 g / L, a Rb concentration of 0.5 g / L, a Cs concentration of 0.5 g / L, and a Na + The concentration is 10g / L and K + The lithium precipitate mother liquor with a concentration of 10 g / L is mixed for extraction;

[0089] (2) mixing the loaded organic phase containing Li, Rb and Cs obtained in step (1) with a hydrochloric acid solution for stripping, with a ratio (volume of organic phase to volume of aqueous phase) of 20:1, and obtaining an aqueous phase containing 9.7 g / L, 9.5 g / L and 9.3 g / L of Li, Rb and Cs, respectively, after stripping, with a pH value of 7.5, stripping rates of Li, Rb and Cs of 99%, 98% and 97%, respectively, and recoveries of Li, Rb and Cs of 97%, 95% and 93%, respectively;

[0090] (3) The aqueous phase obtained in step (2) was heated at 80° C. for 2 h, and filtered to obtain LiCl, RbCl and CsCl products with purities of 98%, 96% and 97%, respectively.

[0091] Application Example 3

[0092] This application example provides an application of the extractant in the extraction of lithium, rubidium and cesium, and the application comprises the following steps:

[0093] (1) The extractant A obtained in Preparation Example 3 was mixed with sulfonated kerosene to form an extraction system. The pH of the extraction system was adjusted to 8 using potassium hydroxide. Under this condition, the extraction system was mixed with a Li concentration of 2 g / L, a Rb concentration of 0.6 g / L, a Cs concentration of 0.6 g / L, and a Na + The concentration is 20g / L, K + The concentration is 20g / L and NH4 + The lithium battery waste leachate with a concentration of 20 g / L is mixed for extraction;

[0094] (2) mixing the loaded organic phase containing Li, Rb and Cs obtained in step (1) with a sulfuric acid solution for stripping, with a ratio (volume of organic phase to volume of aqueous phase) of 15:1, and obtaining an aqueous phase containing 28.8 g / L, 8.2 g / L and 8.47 g / L of Li, Rb and Cs, respectively, after stripping, with a pH value of 5.5, stripping rates of Li, Rb and Cs of 98%, 95% and 97%, respectively, and recoveries of Li, Rb and Cs of 96%, 91% and 94%, respectively;

[0095] (3) The aqueous phase obtained in step (2) was heated at 110° C. for 0.5 h and centrifuged to obtain Li2SO4, Rb2SO4 and Cs2SO4 products with purities of 98%, 96% and 97%, respectively.

[0096] Application Example 4

[0097] This application example provides an application of the extractant in the extraction of lithium, rubidium and cesium, and the application comprises the following steps:

[0098] (1) The extractant B obtained in Preparation Example 1 was mixed with sulfonated kerosene to form an extraction system. The pH of the extraction system was adjusted to 14 using potassium hydroxide. Under this condition, the extraction system was mixed with a Li concentration of 5 g / L and a Na + The concentration is 20g / L and K + The lithium battery waste leachate with a concentration of 20 g / L is mixed for extraction;

[0099] (2) mixing the Li-containing loaded organic phase obtained in step (1) with a sulfuric acid solution for stripping, with a ratio (volume of organic phase to volume of aqueous phase) of 8:1, and obtaining an aqueous phase containing 38.4 g / L of Li after stripping, with a pH value of 5 for the aqueous phase, a stripping rate of Li of 99%, and a recovery rate of Li of 96%;

[0100] (3) The aqueous phase obtained in step (2) was heated at 100° C. for 1 h and centrifuged to obtain a Li2SO4 product with a purity of 97%.

[0101] Application Example 5

[0102] This application example provides an application of the extractant in the extraction of lithium, rubidium and cesium, and the application comprises the following steps:

[0103] (1) The extractant B obtained in Preparation Example 2 was mixed with hydrogenated kerosene to form an extraction system. The pH of the extraction system was adjusted to 11.5 using aqueous ammonia. Under this condition, the extraction system was mixed with a Li concentration of 1 g / L and a Na + The concentration is 30g / L, K + The concentration is 5g / L and NH4 + The leaching solution of lithium ore with a concentration of 5 g / L is mixed for extraction;

[0104] (2) The Li-containing loaded organic phase obtained in step (1) was mixed with a weak acid solution formed by continuously passing CO2 into water for stripping, with a ratio (volume of organic phase to volume of aqueous phase) of 1:0.25. After stripping, an aqueous phase containing 3.69 g / L of Li was obtained. The pH value of the aqueous phase was 6, the stripping rate of Li was 95%, and the recovery rate of Li was 92%;

[0105] (3) The aqueous phase obtained in step (2) was heated at 100° C. for 1 h, and the Li2CO3 product was obtained after centrifugation with a purity of 99%.

[0106] Application Example 6

[0107] This application example provides an application of the extractant in the extraction of lithium, rubidium and cesium, and the application comprises the following steps:

[0108] (1) The extractant B obtained in Preparation Example 3 was mixed with sulfonated kerosene to form an extraction system. The pH of the extraction system was adjusted to 9 with ammonia water. Under this condition, the extraction system was mixed with a Li concentration of 3 g / L and a Na + The concentration is 30g / L, K + The concentration is 5g / L and NH4 + The leaching solution of lithium ore with a concentration of 5 g / L is mixed for extraction;

[0109] (2) The Li-containing loaded organic phase obtained in step (1) was mixed with a weak acid solution formed by continuously passing SO2 into water for stripping, with a ratio (volume of organic phase to volume of aqueous phase) of 1:0.5. After stripping, an aqueous phase containing 5.76 g / L of Li was obtained, the pH value of the aqueous phase was 6, the stripping rate of Li was 99%, and the recovery rate of Li was 96%;

[0110] (3) The aqueous phase obtained in step (2) is added with sodium carbonate and heated at 100° C. for 1 h. After centrifugation, a Li2CO3 product with a purity of 98% is obtained.

[0111] Comparative application example 1

[0112] This comparative example provides an application of the extractant in the extraction of lithium, rubidium and cesium, except that the step (1) of adjusting the pH of the extraction system to 11.5 using sodium hydroxide is replaced by adjusting the pH of the extraction system to 5 using hydrochloric acid, and the remaining steps are the same as those in Application Example 1.

[0113] The stripping rates of Li, Rb and Cs are 35%, 5% and 6% respectively, and the recovery rates of Li, Rb and Cs are 65%, 20% and 10% respectively; LiCl, RbCl and CsCl products are obtained with purities of 79%, 35% and 20% respectively.

[0114] Comparative Application Example 2

[0115] This comparative example provides an application of the extractant in the extraction of lithium, rubidium and cesium. Except that no diluent is added to the extraction system in step (1), the remaining steps are the same as those in Application Example 1.

[0116] The stripping rates of Li, Rb and Cs are 85%, 77% and 69% respectively, and the recovery rates of Li, Rb and Cs are 68%, 55% and 46% respectively; LiCl, RbCl and CsCl products are obtained with purities of 88%, 55% and 45% respectively.

[0117] Comparative Application Example 3

[0118] This comparative example provides an application of the extractant in the extraction of lithium, rubidium and cesium. In step (1), the extractant A obtained in Preparation Example 1 is replaced with 4-tert-butyl-2-(α-methylbenzyl)phenol (t-BAMBP) and mixed with hydrogenated kerosene to form an extraction system, and the remaining steps are the same as those in Application Example 1.

[0119] The stripping rates of Li, Rb and Cs are 5%, 67% and 69% respectively, and the recovery rates of Li, Rb and Cs are 15%, 57% and 66% respectively; LiCl, RbCl and CsCl products are obtained with purities of 20%, 50% and 69% respectively.

[0120] Comparative Application Example 4

[0121] This comparative example provides an application of the extractant in the extraction of lithium, rubidium and cesium. In the step (1), the extractant B obtained in Preparation Example 1 is replaced with dodecylphenyl-methyl-β-diketone (LIX54) mixed with hydrogenated kerosene to form an extraction system, and the rest is the same as Application Example 4.

[0122] The Li stripping rate was 51%, and the Li recovery rate was 25%. The Li2SO4 product was obtained with a purity of 18%.

[0123] Comparing Application Example 1 with Comparative Application Examples 1-2, if the pH of the extraction system is acidic or there is no diluent in the extraction system, it is not conducive to the extraction and recovery of Li, Rb and Cs, and the purity of the obtained product is not high; this shows that the alkaline environment and the presence of a diluent in the extraction system are important conditions to ensure that the extractant can efficiently extract the valuable metals Li, Rb and Cs.

[0124] Comparing Application Example 1 with Comparative Application Example 3, the extractant t-BAMBP containing a benzene ring connected to a phenolic hydroxyl group can extract Cs and Rb, but cannot recover the Li resources in the solution; comparing Application Example 4 with Comparative Application Example 4, the extractant LIX54 containing a diketone can extract the valuable metal Li, but the extraction rate of Li is poor and the purity of the obtained product is not high; this shows that there are still huge differences in the extraction effect between homologous series, and the extractant of the present invention can achieve efficient extraction of Li, Rb and Cs.

[0125] The applicant declares that the present invention illustrates the detailed structural features and application processes of the present invention through the above-mentioned preparation examples and application examples, but the present invention is not limited to the above-mentioned detailed structural features and application processes, that is, it does not mean that the present invention must rely on the above-mentioned detailed structural features and application processes to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of the raw materials of the product of the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. An extractant, characterized in that The extractant includes extractant A as shown in formula I or extractant B as shown in formula II: Wherein, R1 in the formula I is a C4-C12 straight chain or branched alkyl group, and R2 is a n-octyl group or an isooctyl group; R3 in the formula II is a C8-C12 straight chain or branched alkyl group, and R4 is a n-octyl group or an isooctyl group; The synthesis method of the extractant A comprises: 4-chloromethylstyrene and alkylphenol are subjected to an addition reaction to obtain an alkyl-2-(1-(4-(chloromethyl)phenyl)ethyl)phenol intermediate, sodium hypophosphite and unsaturated olefin are subjected to an addition-reduction reaction to obtain a dialkylphosphine oxide intermediate, and the two intermediates are subjected to an addition-hydrolysis reaction to obtain the extractant A.

2. The extractant according to claim 1, characterized in that The synthesis method of the extractant B comprises: a carbonyl compound containing a benzene ring and a halogenated carboxylic acid ester undergo a Claisen condensation reaction under base catalysis to obtain a β-diketone intermediate, and the β-diketone intermediate and a dialkylphosphine oxide undergo an addition-hydrolysis reaction to obtain the extractant B.

3. Use of the extractant as claimed in claim 1 or 2 in the extraction of lithium, rubidium and cesium, characterized in that: The application comprises the following steps: (1) The extractant according to claim 1 or 2 is mixed with a diluent to form an extraction system, and the system is mixed with an alkali metal-containing liquid under alkaline conditions to perform extraction; (2) mixing the organic phase obtained after extraction in step (1) with a stripping solution, and stripping to obtain an aqueous phase; (3) The aqueous phase obtained in step (2) is precipitated or heated to separate the alkali metal-containing compound or enriched product.

4. The use according to claim 3, characterized in that: The concentration of the extractant A in the extraction system of step (1) is 0.2-1.0 mol / L.

5. The use according to claim 3, characterized in that: The concentration of the extractant B in the extraction system of step (1) is 0.2-1.0 mol / L.

6. The use according to claim 3, characterized in that: The diluent in step (1) includes any one of hydrogenated kerosene, sulfonated kerosene, aliphatic hydrocarbons or aromatic hydrocarbons, or a combination of at least two thereof.

7. The use according to claim 3, characterized in that: The feed solution in step (1) includes any one of lithium ore leaching solution, lithium precipitation mother solution, lithium battery waste leaching solution, salt lake brine or secondary resource recovery solution, or a combination of at least two of them.

8. The use according to claim 3, characterized in that: The alkaline condition in step (1) is to adjust the pH to 8-14.

9. The use according to claim 8, characterized in that: The alkaline condition in step (1) is to adjust the pH to 11.5-12.

5.

10. The use according to claim 8, characterized in that: The regulator used for adjusting the pH includes any one of sodium hydroxide, potassium hydroxide or ammonia solution or a combination of at least two of them.

11. The use according to claim 3, characterized in that: The alkali metal in the slurry of step (1) includes any one of Li, Rb or Cs or a combination of at least two of them.

12. The use according to claim 11, characterized in that: The concentration of Li, Rb or Cs is independently 0.1-5 g / L.

13. The use according to claim 3, characterized in that: The feed solution in step (1) also includes Na + , K + or NH4 + Any one or a combination of at least two of the following.

14. The use according to claim 13, characterized in that The Na + , K + and / or NH4 + The total concentration is 10-200g / L.

15. The use according to claim 3, characterized in that: The stripping solution in step (2) is an acidic solution or a mixed solution of a weakly acidic gas and water.

16. The use according to claim 15, characterized in that The acidic solution includes any one of hydrochloric acid solution, sulfuric acid solution, phosphoric acid solution, citric acid solution or malic acid solution, or a combination of at least two thereof.

17. The use according to claim 15, characterized in that: The weakly acidic gas includes CO2 and / or SO2.

18. The use according to claim 3, characterized in that: The total concentration of alkali metal ions in the aqueous phase of step (2) is greater than 6 g / L.

19. The use according to claim 3, characterized in that: The pH of the aqueous phase in step (2) is 3-7.

5.

20. The use according to claim 3, characterized in that: The precipitation treatment in step (3) is to add a precipitant.

21. The use according to claim 20, characterized in that The precipitant is sodium carbonate and / or sodium carbonate solution.

22. The use according to claim 3, characterized in that: The temperature of the heating treatment in step (3) is 80-110°C.

23. The use according to claim 3, characterized in that: The heating time of step (3) is 0.5-2h.

24. The use according to claim 3, characterized in that: The separation method in step (3) includes any one of filtration, suction filtration or centrifugation, or a combination of at least two of them.

25. The use according to claim 3, characterized in that The alkali metal-containing compound or enriched product in step (3) is Li or chloride, sulfate or carbonate of Li, Rb and Cs.

26. The use according to claim 3, characterized in that The application comprises the following steps: (1) 0.2-1.0 mol / L of the extractant A described in claim 1 or 2 or 0.2-1.0 mol / L of the extractant B described in claim 1 or 2 is mixed with a diluent to form an extraction system, and the mixture is mixed with an alkali metal containing Li, Rb or Cs at a concentration of 0.1-5 g / L and a total concentration of Na2O3 containing 10-200 g / L at a pH of 8-14. + , K + and / or NH4 + The feed liquid is mixed for extraction; (2) mixing the organic phase obtained after the extraction in step (1) with an acidic solution or mixing the organic phase with a mixed solution of a weakly acidic gas and water, and stripping to an aqueous phase, wherein the total concentration of alkali metal ions in the aqueous phase is greater than 6 g / L, and the pH of the aqueous phase is 3-7.5; (3) The aqueous phase obtained in step (2) is subjected to precipitation treatment or heated at 80-110° C. for 0.5-2 h to separate the chloride, sulfate or carbonate containing Li or Li, Rb and Cs.

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