A synergistic extractant and a method for selectively extracting nickel and cobalt from an acidic impure solution

Abstract

The application discloses a kind of synergistic extractant and method for selectively extracting nickel and cobalt from acidic impurity-containing solution, and belongs to the technical field of hydrometallurgy.The synergistic extractant contains compound APDPA and compound NSA, which has selective extraction capacity for nickel ions and / or cobalt ions.Application of the synergistic extractant can selectively extract nickel and / or cobalt from acidic impurity-containing solution, achieve efficient separation of nickel and / or cobalt from various impurities such as iron, aluminum, chromium, manganese, magnesium and calcium, and high multiple enrichment of nickel and / or cobalt.The method has the advantages of short process, high nickel and cobalt yield, large separation coefficient of nickel and cobalt from impurity metals, good two-phase phase separation effect and small extractant loss.

Description

Technical Field

[0001] This invention relates to a synergistic extractant, particularly to a synergistic extractant for nickel-cobalt extraction, and a method for selectively extracting nickel-cobalt from acidic impurity solutions using the synergistic extractant, belonging to the field of hydrometallurgical technology. Background Technology

[0002] Nickel and cobalt are important strategic metals with wide industrial applications. They share similar properties and are often found together in mineral and secondary resources. Hydrometallurgy in acidic systems is currently one of the main methods for extracting nickel and cobalt from low-grade nickel and cobalt resources (such as nickel laterite, copper-cobalt ore, spent nickel-cobalt catalysts, and spent lithium-ion batteries). During acidic hydrometallurgical processes involving low-grade nickel / cobalt materials, various acidic nickel / cobalt solutions containing impurities are generated, such as high-pressure sulfuric acid leaching solutions from nickel laterite ore, sulfuric acid leaching residue from copper-cobalt ore extraction, sulfuric acid leaching solutions from electroplating sludge, and hydrochloric acid leaching solutions from spent nickel-cobalt catalysts. These acidic solutions contain not only valence metals nickel and cobalt ions but also large amounts of base metal impurities such as iron, aluminum, manganese, magnesium, calcium, and chromium. Currently, the mainstream industrial method for extracting nickel and cobalt from these acidic nickel / cobalt solutions containing large amounts of impurities is the "precipitation removal of iron and aluminum—nickel-cobalt precipitation" process. This method first involves multi-step hydrolysis precipitation to remove iron and aluminum. After iron and aluminum removal, the liquid is then precipitated in two steps using an alkaline precipitant (caustic soda, magnesium hydroxide / magnesium oxide, lime, etc.) to obtain an intermediate product – crude nickel-cobalt hydroxide (MHP). This method suffers from problems such as a long process, significant loss of nickel and cobalt during precipitation, and low purity of MHP requiring further purification.

[0003] Compared to traditional chemical precipitation methods, solvent extraction offers advantages such as high selectivity, fast reaction rate, good separation effect, and ease of automation. It is a highly efficient enrichment and separation method widely used for the separation of metal ions in aqueous solutions, such as nickel / cobalt and copper / iron. If preferential and selective extraction of nickel and cobalt can be achieved from acidic solutions containing impurities, it would shorten the process, increase yield, and reduce costs. However, commonly used organophosphoric acid extractants (such as P507, Cynex 272, and P204) react with Fe... 3+ Al 3+ Mn 2+ Ca 2+ These substances have a strong affinity for the aforementioned impurities, making them more effective at extracting these impurities than nickel and cobalt. This makes it difficult to selectively extract nickel and cobalt from acidic solutions containing these impurities.

[0004] To address the aforementioned issues, Chinese patent CN103421952B discloses a synergistic extractant and a method for selectively extracting nickel from acidic nickel-containing solutions. This method uses a synergistic extractant composed of naphthalenesulfonic acid (salt) / pyridine carboxylate to preferentially and selectively extract nickel from acidic nickel-containing solutions, achieving the separation of nickel from impurities such as iron, aluminum, manganese, magnesium, calcium, and chromium. However, the ester bond (–COOR) in the pyridine carboxylate molecule is easily degraded under high acid or concentrated acid back-extraction conditions. This leads to significant extractant loss during the extraction process and limits the acid concentration of the back-extraction agent, making it difficult to increase the nickel concentration in the back-extraction solution. Furthermore, this synergistic extraction system has a weak ability to preferentially extract cobalt, resulting in poor cobalt extraction. 2+ The extraction equilibrium pH is high, making it difficult to perform at lower pH conditions (e.g., pH ≤ 2, Fe). 3+ Al 3+ To achieve efficient cobalt extraction without hydrolysis, a pre-neutralization and precipitation step is required to remove iron and aluminum for cobalt resources or nickel-cobalt coexisting resources. Due to the limitations of naphthalenesulfonic acid (salt) / pyridine carboxylic acid esters, Chinese patent application (publication number: CN116356142A) discloses a bispyridine extractant, its preparation method, and its application as a nickel-cobalt extractant. This bispyridine extractant has the following molecular structure: Where R is C 12 ~C 25 The alkyl group of the bispyridyl extractant and naphthalenesulfonic acid (NSA) form a synergistic extraction system that not only exhibits good selectivity for nickel and cobalt but also demonstrates structural stability and resistance to degradation at high acid concentrations, effectively addressing the issues of high extractant loss and difficulty in increasing the nickel and cobalt concentration in the back-extraction solution. However, the steric hindrance effect of the long-carbon alkyl group R in the bispyridyl extractant affects the synergistic extractant's ability to extract nickel and cobalt ions, particularly cobalt ions, leading to reduced Co ion extraction. 2+ The extraction equilibrium pH is high, making it difficult to achieve extraction under lower pH conditions (e.g., pH ≤ 2, Fe). 3+ Al 3+ This method achieves efficient cobalt extraction without hydrolysis. However, for cobalt resources or nickel-cobalt coexisting resources, a pre-treatment neutralization and precipitation step is required to remove iron and aluminum. Furthermore, the phase separation rate during extraction and back-extraction in this synergistic extraction system is too slow to meet industrial extraction requirements. Summary of the Invention

[0005] To address the drawbacks of existing hydrometallurgical processes for extracting nickel and / or cobalt from low-grade nickel and / or cobalt resources, and the shortcomings of existing pyridine-based extractants such as easy degradation under acidic conditions, slow phase separation rate, and weak cobalt extraction capacity, the first objective of this invention is to provide a synergistic extractant with strong selectivity for nickel and cobalt, stable chemical properties, and fast phase separation rate. This synergistic extractant has selective chelation extraction capability for nickel and / or cobalt ions, is chemically stable in acidic solutions, and can selectively extract nickel and / or cobalt from complex solutions, thereby achieving selective separation of nickel and / or cobalt ions from impurity ions such as iron, aluminum, chromium, manganese, magnesium, and calcium ions.

[0006] The second objective of this invention is to provide a method for selectively extracting nickel and cobalt from an acidic impurity solution using the aforementioned synergist. This method enables the preferred and selective extraction of nickel and / or cobalt from the acidic impurity solution, achieving efficient separation and high-multiple enrichment of nickel and / or cobalt from impurities such as iron, aluminum, chromium, manganese, magnesium, and calcium. It has the advantages of high nickel and cobalt yield, good separation effect, fast phase separation speed, short process, low cost, and easy industrialization.

[0007] To achieve the above-mentioned technical objectives, the present invention provides a synergistic extractant comprising the compound APDPA and the compound NSA;

[0008] The compound APDPA is at least one of the compounds with the structure shown in Formula 1:

[0009]

[0010] Formula 1

[0011] The compound NSA is at least one of the compounds with the structure shown in Formula 2:

[0012]

[0013] Formula 2

[0014] in,

[0015] R1 is a C1~C9 alkyl group;

[0016] R2 is a C2~C4 alkane chain;

[0017] R3 and R4 are independently selected from C6~C 12 Alkyl groups;

[0018] M is a cation used to balance the charge.

[0019] In the molecular structure of the compound APDPA of the present invention, R1 is an alkyl group of C1 to C9. The alkyl group can be a straight-chain alkyl group, such as methyl, ethyl, butyl, pentyl, octyl, etc. If the number of carbon atoms exceeds 3, the alkyl group can be a branched alkyl group, such as isopropyl, isobutyl, isooctyl, etc.

[0020] In the molecular structure of the compound NSA of this invention, R3 and R4 are C6~C6. 12 Alkyl groups can be straight-chain alkyl groups or branched alkyl groups, such as hexyl, octyl, dodecyl, isooctyl, etc.

[0021] In the molecular structure of the compound NSA of this invention, M can be one of hydrogen ion, ammonium ion, magnesium ion, or alkali metal ion, and n is the valence number of M.

[0022] The synergistic extractant of this invention employs a novel bispyridyl compound, APDPA, in combination with compound NSA. Compared to existing long-chain alkyl bispyridyl extractants, APDPA is characterized by abandoning the hydrophobic design of long-chain alkyl groups and instead adopting a robust yet flexible alkylphenoxy-alkylene-bridged bispyridyl structure. Its hydrophobicity is provided by both the alkylphenoxy group and the appropriately long C2-C4 alkylene chain. On the one hand, the alkylphenoxy-alkylene structure significantly reduces the viscosity of the organic phase and affects the interfacial properties between the two phases, achieving rapid phase separation during the extraction process. On the other hand, the alkylphenoxy-alkylene structure avoids excessive steric hindrance while improving electron-withdrawing ability, significantly enhancing the interaction between the bispyridyl group and Ni. 2+ / Co 2+ The coordination ability of the compound APDPA allows the bispyridine group to form an open, coordinating coordination cavity with the sulfonic acid group in the compound NSA, enabling efficient recognition and stable interaction with Ni under low pH conditions. 2+ / Co 2+ Formation of a complex, while repelling Fe 3+ Al 3+ Ca 2+ Mg 2+ Mn 2+ Cr 3+ Impurity ions can not only lower the extraction equilibrium pH, but also significantly improve the extraction efficiency for Ni. 2+ / Co 2+Its high extraction selectivity makes it particularly suitable for directly processing acidic leachates from low-grade nickel-cobalt resources such as laterite nickel ore, copper-cobalt ore, and spent catalysts, eliminating the need for pre-neutralization and precipitation to remove iron and aluminum before extraction. Furthermore, the compound APDPA does not contain easily hydrolyzed ester bonds, exhibiting excellent chemical stability in strong acid and oxidizing environments. This significantly reduces extractant degradation and consumption, and enables nickel-cobalt back-extraction under high acid conditions, achieving high-level enrichment of nickel and cobalt and significantly increasing the nickel-cobalt concentration in the back-extraction solution (e.g., total nickel-cobalt concentration greater than 100 g / L). This truly achieves a balance between shortened process, increased metal yield, and reduced costs.

[0023] The compound APDPA in the synergistic extractant of this invention has a bispyridine chelating group, which can better form stable coordination bonds with nickel and cobalt ions. The N of the bispyridine group forms a unique coordination structure with nickel and cobalt ions, which also facilitates the participation of the sulfonic acid group in the compound NSA in coordination to form an extractant, forming a multi-site bound extractant and improving the selectivity for nickel and cobalt ions.

[0024] As a preferred embodiment, the molar ratio of compound APDPA to compound NSA in the synergistic extractant is 1:1 to 1:4. The molar ratio of compound APDPA to compound NSA is further 1:1 to 1:2. The synergistic extractant composed of compound APDPA (Structure 1) and compound NSA (Structure 2) of this invention can further reduce the extraction equilibrium pH of nickel and cobalt, inhibit the extraction of impurity metal ions, and lower the extraction equilibrium pH of nickel and cobalt to below 2.0, eliminating the need for a pre-neutralization precipitation step to remove iron and aluminum before extraction.

[0025] This invention also provides a method for selectively extracting nickel and cobalt from an acidic aqueous solution containing impurities using the aforementioned synergistic extractant. The method involves performing single-stage or multi-stage countercurrent extraction on an acidic aqueous solution containing nickel and / or cobalt and other impurity cations using an organic phase containing the synergistic extractant. The resulting loaded organic phase is then subjected to single-stage or multi-stage countercurrent back-extraction directly or after washing with an inorganic acid aqueous solution to obtain a nickel and / or cobalt-containing solution. The back-extracted organic phase is then returned to the extraction process, either directly or after saponification.

[0026] The organic phase consists of a synergistic extractant and an organic diluent. The concentration of NSA in the synergistic extractant is 0.1–0.4 mol / L, and the molar ratio of APDPA to NSA is 1:1–1:4. The organic diluent is sulfonated kerosene, No. 260 solvent oil, Escaid 110, or C6–C4 solvent. 13 aliphatic monohydric alcohols, C8~C 12 At least one of alkylphenols and trialkyl phosphates (P(OR)3, where R is an alkyl group, such as ethyl, propyl, octyl, etc.).

[0027] As a preferred embodiment, the organic phase containing the synergistic extractant is extracted into an acidic aqueous solution containing nickel ions and / or cobalt ions and other impurity cations, and then the two phases are separated to obtain an organic phase loaded with nickel ions and / or cobalt ions.

[0028] As a preferred embodiment, the acidic aqueous solution containing nickel and / or cobalt and other impurity cations is an aqueous sulfate solution.

[0029] As a preferred embodiment, the pH value of the acidic aqueous solution containing nickel and / or cobalt and other impurity cations is between 1.0 and 7.0.

[0030] As a preferred embodiment, the other impurity cations include at least one impurity metal ion selected from iron ions, aluminum ions, chromium ions, manganese ions, magnesium ions, and calcium ions. The selective extraction method for nickel and cobalt using the present invention is less affected by impurity cations such as iron ions, aluminum ions, chromium ions, manganese ions, magnesium ions, and calcium ions, and the extractant exhibits strong selective chelation extraction ability for nickel and cobalt ions.

[0031] As a preferred embodiment, the extraction conditions are as follows: extraction employs a single-stage or multi-stage countercurrent extraction method, with the number of multi-stage countercurrent extraction stages ranging from 2 to 10; the volumetric flow rate ratio (O / A) of the organic phase to the aqueous phase is 1 / 5 to 5 / 1; the extraction temperature is 10 to 60°C; and the equilibrium pH of the extraction aqueous phase is 1.0 to 4.0. The equilibrium pH of the extraction aqueous phase is further preferably 1.5 to 2.5. The equilibrium pH of the extraction aqueous phase can be adjusted by adding alkali or acid to the extraction stages, or by adjusting the degree of saponification of the organic phase.

[0032] As a preferred embodiment, the organic phase loaded with nickel ions and / or cobalt ions is back-extracted directly or after washing with acid to obtain a back-extraction solution containing nickel ions and / or cobalt ions.

[0033] As a preferred embodiment, the acid solution includes at least one of sulfuric acid, hydrochloric acid, and nitric acid.

[0034] As a preferred embodiment, the H in the acid solution + The concentration is 0.5~6 mol / L.

[0035] As a preferred embodiment, the back-extraction conditions are as follows: the back-extraction adopts single-stage or multi-stage countercurrent back-extraction, the number of multi-stage countercurrent extraction stages is between 2 and 10; the volume flow ratio (O / A) of organic phase to aqueous phase is 1 / 1 to 30 / 1, and the back-extraction temperature is 10 to 60℃.

[0036] The aqueous solution containing nickel ions and / or cobalt ions and other impurity cations involved in this invention can be an inorganic acid leaching solution such as laterite nickel ore, electroplating sludge, or waste nickel-cobalt catalyst. For example, in a complex metal ion solution containing cobalt ions and / or nickel ions, the concentration of nickel ions is 0.5~4 g / L, the concentration of cobalt ions is 0.1~2 g / L, the concentration of magnesium ions is 10~30 g / L, the concentration of iron ions is 1~3 g / L, the concentration of aluminum ions is 1~30 g / L, the concentration of manganese ions is 0.5~3 g / L, and the concentration of chromium ions is 0.2~10 g / L, etc.

[0037] The compound APDPA of Formula 1 of the present invention is synthesized by the following method:

[0038] 1) Substitution reaction of disubstituted halogenated hydrocarbons of formula 3 with phenolic compounds of formula 4. Thus, the intermediate structure of Formula 5 is obtained;

[0039] 2) The intermediate of Formula 5 above is subjected to substitution reaction II with N,N-dimethylpyridinium of Formula 6 to obtain the target compound - compound APDPA;

[0040]

[0041] Formula 3

[0042]

[0043] Formula 4

[0044]

[0045] Formula 5

[0046]

[0047] Formula 6

[0048] in,

[0049] R1 is a C1~C9 alkyl group;

[0050] R2 is a C2~C4 alkane chain;

[0051] X is a halogen substituent.

[0052] Compared with the prior art, the technical solution of the present invention brings the following beneficial technical effects:

[0053] 1) The synergistic extractant and nickel-cobalt synergistic extraction method used in this invention have advantages over the traditional "precipitation and impurity removal - nickel-cobalt precipitation" process, including shorter process, higher nickel-cobalt yield, better impurity removal effect, lower chemical reagent consumption, and lower operating cost.

[0054] 2) Compared with existing synergistic extractants composed of naphthalene sulfonate / pyridine carboxylate and nickel-cobalt extraction methods, the synergistic extractant used in this invention has the characteristics of good acid resistance and non-degradability, which can effectively solve the problems of high extractant consumption and difficulty in increasing the concentration of nickel-cobalt back-extraction solution.

[0055] 3) Compared with existing synergistic extractants composed of naphthalene sulfonate / long-chain alkyl dipyridyl compounds and nickel-cobalt extraction methods, this invention can effectively solve the problem of slow two-phase separation speed, significantly improve the processing capacity of extraction equipment, and save equipment and extractant usage.

[0056] 4) Compared with the two existing synergistic extractants and nickel synergistic extraction methods mentioned above, the synergistic extractant used in this invention has stronger nickel-cobalt extraction ability, especially stronger cobalt extraction ability. It can effectively solve the problem of low cobalt yield in the selective extraction of nickel and cobalt from solutions containing impurities such as iron and aluminum under low pH conditions where iron and aluminum do not hydrolyze. Thus, the neutralization precipitation process to remove iron and aluminum before extraction can be eliminated.

[0057] 5) Compared with existing synergistic extractants and nickel synergistic extraction methods, this invention is easier to industrialize. Attached Figure Description

[0058] 【 Figure 1 [Image shows the high-resolution mass spectrometry (MS) analysis results of the bromoaromatic ethers in Example 1.]

[0059] 【 Figure 2 [Image shows the high-resolution mass spectrometry (MS) analysis results of compound APDPA in Example 1.]

[0060] 【 Figure 3 [Image showing the extraction equilibrium pH of the laterite nickel ore extraction solution in Example 3]

[0061] 【 Figure 4 [Image 1] shows the infrared spectrum of the cobalt- or nickel-loaded organic phase in Example 12, where a is the cobalt-loaded organic phase and b is the nickel-loaded organic phase. Detailed Implementation

[0062] The following specific embodiments are intended to further illustrate the content of the present invention, rather than to limit the scope of protection of the claims.

[0063] In the embodiments, the distribution ratio D, separation coefficient β, extraction rate E (%), impurity removal rate Y (%), and enrichment factor N are calculated according to equations (1) to (5), respectively:

[0064] D=C MO / C MR (1)

[0065] β M1 / M2 =D M1 / D M2 (2)

[0066] E1 = Co × R / C F ×100% (3)

[0067] N= C MS / C MF (4)

[0068] Y=(C MF / C VF -C MR / C VR ) / (C MF / C VF (5) ×100%

[0069] In equation (1), C MO C MR Represent the concentrations (g / L) of metal ions M in the supported organic phase and the raffinate, respectively; in equation (2), β M1 / M2 The separation coefficient between metal ion M1 and metal ion M2 is represented by equation (3), C. F Co represents the concentration (g / L) of metal ions in the feed liquid and the supported organic phase, respectively, and R represents the ratio of the volumetric flow rates of the organic phase and the aqueous phase; in equation (4), C MS and C MF Represent the concentrations (g / L) of element M in the back-extraction solution and the feed solution, respectively; in equation (5), C IF C VF C represents the concentrations (g / L) of impurity metal ions I and target valuable metal ions V in the feed solution, respectively. IS C VS The values ​​represent the concentrations (g / L) of impurity metal ion M and target valuable metal ion V in the back-extraction solution, respectively, where the target valuable metal ion V is Ni. 2+ and Co 2+ Its concentration is the sum of the two.

[0070] Example 1

[0071] Synthesis of compound APDPA:

[0072] (1) Take 0.5 mol of p-tert-butylphenol and add it to 0.6 mol of 20 wt% NaOH solution. Heat to 70 °C and stir to dissolve. After complete dissolution, transfer to a three-necked flask and add 1 mol of dibromoethane. The reaction temperature is 85 °C and the reaction time is 5.5 h. After the reaction is complete, wash with a solution of 10 g NaOH + 10 g MeOH / 500 g H2O until the aqueous solution is clear. Evaporate excess dibromoethane and collect the product (bromoaromatic ether) with a purity of 95%. The mass spectrometry characterization results of the product are as follows: Figure 1As shown.

[0073] (2) Take 0.2 mol of the bromoaromatic ether product obtained in step (1) and 0.2 mol of 2,2-dipyridinylmethylamine, and dissolve them completely in 100 ml of acetonitrile. Transfer the liquid to a 250 ml beaker, add 0.2 mol of anhydrous potassium carbonate, stir thoroughly, heat to 80 °C, and react for 5 h. After the reaction is complete, first separate the solid and liquid by vacuum filtration, and then evaporate the acetonitrile by rotary evaporation at 80 °C. After evaporation, add 100 ml of toluene to dilute, transfer to a separatory funnel, wash thoroughly with water until the wash water is colorless, evaporate the toluene, and obtain a target product compound APDPA-1 with a purity of 92%, the structural formula of which is shown in Formula 1-1. The product appears as a reddish-black liquid, and the mass spectrometry characterization results are as follows. Figure 2 As shown.

[0074] A similar method can be used to prepare compounds APDPA with different carbon chain lengths (R1 and R2). For example, compounds APDPA-2 and APDPA-3 have the structural formulas shown in Formulas 1-2 and 1-3, respectively.

[0075]

[0076] Formula 1-1

[0077]

[0078] Formula 1-2

[0079]

[0080] Formula 1-3

[0081] Example 2

[0082] Aqueous phase solution: A mixed metal sulfate solution containing Ni. 2+ 1.0g / L, Co 2+ 1.0 g / L, Fe 3+ 1.0 g / L, Mg 2+ 1.0 g / L, pH of the feed solution is 2.0.

[0083] Organic phases: Three organic phases with different compositions were prepared, numbered 1, 2, and 3. The diluent in the organic phases was sulfonated kerosene. Organic phase 1 was a sulfonated kerosene solution of compound APDPA-1 at 0.2 mol / L, organic phase 2 was a sulfonated kerosene solution of dinonylnaphthalenesulfonic acid (NSA) at 0.20 mol / L, and organic phase 3 was a sulfonated kerosene solution of compound APDPA-1 (0.20 mol / L) + DNSSA (0.2 mol / L).

[0084] Extraction and separation operation: The above three organic phases were subjected to single-stage extraction using a separatory funnel at a ratio (volume ratio of organic phase to aqueous phase) of 1:1. The extraction equilibrium time was 10 min, and the temperature was 30℃. The experimental results are shown in Table 1.

[0085]

[0086] Table 1 shows that when compound APDPA was used alone for extraction, Ni 2+ Co 2+ Fe 3+ Mg 2+ The extraction rates were all less than 0.5%, meaning they were almost not extracted. However, when NSA was used alone for extraction, Ni... 2+ Co 2+ Fe 3+ Al 3+ Mg 2+ The extraction rates were all between 30% and 52%, making it difficult to separate nickel and cobalt from impurities such as iron, aluminum, and magnesium. When a synergistic extractant composed of compounds APDPA-1 and NSA was used, Ni… 2+ and Co 2+ The extraction rates increased to 98.88% and 97.71%, respectively, while Fe... 3+ Mg 2+ The extraction rates decreased to 4.21% and 4.32%, respectively; the partition ratios (D) of nickel and cobalt reached 88.29 and 42.67, respectively, which were much larger than the sum of the partition ratios when using compounds APDPA and NSA alone; the partition ratios of iron and magnesium were 0.044 and 0.045, respectively, which were much smaller than the sum of the partition ratios when using compounds APDPA and NSA alone. Meanwhile, the separation coefficients (β) of Ni / Fe and Ni / Mg were above 1900, and the separation coefficients (β) of Co / Fe, Co / Al, and Co / Mg were all greater than 900, indicating good selective extraction of nickel and cobalt. This demonstrates that the synergistic extractant composed of compounds APDPA and NSA has a significant synergistic extraction effect on nickel and cobalt, and a significant anti-synergistic effect on impurity ions such as iron, aluminum, and magnesium.

[0087] Example 3

[0088] Aqueous phase solution: High-pressure sulfuric acid leaching solution of lateritic nickel ore, containing Ni 3.21 g / L, Co 0.312 g / L, Fe 3.13 g / L, Al 2.31 g / L, Cr 0.242 g / L, Mn 1.17 g / L, Mg 30.1 g / L, Ca 0.472 g / L, with a pH of 1.8.

[0089] Organic phases: Two organic phases with different compositions were prepared, numbered 4 and 5. Organic phase 4 contained 0.20 mol / L NNPA and 0.20 mol / L DNSSA, wherein the structure of compound NNPA is Formula 3, where R is a 14-alkyl group. Organic phase 5 contained 0.20 mol / L APDPA-1 and 0.20 mol / L DNSSA. The diluent for both organic phases was a mixture of n-decanol and solvent oil No. 260 in a volume ratio of 1:2.

[0090]

[0091] Formula 3

[0092] Extraction and separation operation: Before extraction, organic phases No. 4 and No. 5 were saponified using a 10 mol / L NaOH solution as the saponifying agent, with a saponification rate of 70% (based on NSA). The two saponified organic phases were then mixed with the feed solution at a ratio (organic phase to aqueous phase volume ratio) of 1 / 1 (100 mL / 100 mL) using a separatory funnel in a mixing shaker for 10 min at 30℃. After mixing was stopped, the mixture was allowed to stand for phase separation, and the time for complete phase separation was measured. Samples were then taken for analysis. The experimental results are shown in Table 2.

[0093] Table 2 shows that compared with organic phase 4, organic phase 5 exhibits the following improvements: Firstly, the extraction and phase separation time is significantly improved, with a separation time of only 2.5 min, shortened to 1 / 6 of the actual industrial production time; secondly, the extraction rates of nickel and cobalt are significantly enhanced, reaching 81.22% and 79.34% respectively, representing increases of 1.8 and 3.13 times respectively, with cobalt showing a greater increase. Furthermore, the extraction rates of impurities Fe, Al, Cr, Mn, Mg, and Ca have decreased, indicating a significant improvement in the separation effect between nickel / cobalt and impurities.

[0094] This demonstrates that, compared to the long-chain alkyl hydrophobic dipyridine structure, the alkylphenoxy-alkylene-bridged dipyridine structure used in this invention has significant advantages in terms of nickel-cobalt extraction capability, separation effect of nickel-cobalt from impurities, and phase separation performance.

[0095]

[0096] Example 4

[0097] Aqueous phase solution: High-pressure sulfuric acid leaching solution of lateritic nickel ore, containing Ni 3.21 g / L, Fe 3.13 g / L, Al 2.31 g / L, Cr 0.242 g / L, Co 0.312 g / L, Mn 1.17 g / L, Mg 30.1 g / L, Ca 0.472 g / L, with a pH of 1.8.

[0098] Organic phase: prepared from compound APDPA-2, DNSSA and diluent, wherein compound APDPA-2 is 0.3 mol / L, DNSSA is 0.3 mol / L, and the diluent is a mixture of n-decyl alcohol and No. 260 solvent oil in a volume ratio of 1:2.

[0099] Extraction and separation operation: By controlling different saponification rates, the equilibrium pH value during the extraction process can be controlled. The organic phase was saponified using 10 mol / L NaOH as the saponifying agent (saponification rate was calculated based on the NSA of the compound). Organic phases with different saponification rates were contacted with the aqueous feed solution for single-stage extraction, with an O / A ratio of 1 / 1, a contact time of 10 min, and a temperature of 30℃. The extraction and separation effects under different aqueous equilibrium pH conditions were obtained. Experimental results are as follows: Figure 3 As shown.

[0100] Figure 3 The results showed that within the aqueous equilibrium pH range of 1.0–2.0, the extraction rates of Ni and Co increased significantly with increasing equilibrium pH, with Ni extraction rates ranging from 60% to 85% and Co extraction rates ranging from 15% to 85%. While the extraction rates of impurities Fe, Al, Cr, Mn, Mg, and Ca showed an increasing trend, they were all less than 8%. Particularly when the aqueous equilibrium pH was between 1.5 and 2.0, the extraction rates of Ni and Co were similar, both ranging from 60% to 85%. Therefore, the synergistic extractant composed of compounds APDPA-1 (Formula 1-1) and DNSSA (Formula 2) can effectively extract Fe... 3+ Al 3+ ,Cr 3+ Selective extraction of Ni at pH values ​​(1.5~2) that prevent hydrolysis and precipitation. 2+ and Co 2+ This enables efficient separation of nickel and cobalt from impurities such as iron, aluminum, chromium, manganese, magnesium, and calcium.

[0101] Example 5

[0102] Aqueous phase feed solution: Same as in Example 3

[0103] Organic phase: It is prepared from compound APDPA-2, dioctylnaphthalenesulfonic acid and diluent, wherein compound APDPA-2 is 0.3 mol / L, dioctylnaphthalenesulfonic acid is 0.3 mol / L, and the diluent is a mixed solvent of TBP and No. 260 solvent oil with a volume ratio of 1:2.

[0104] Stripping agent: 2.5 mol / L H2SO4 aqueous solution

[0105] Extraction and separation operation: Before extraction, the organic phase was saponified using a 10 mol / L NaOH solution, with a saponification rate of 80% (based on NSA of the compound). The saponified organic phase and aqueous feed solution were subjected to 6-stage countercurrent extraction at a flow ratio of O / A = 1 / 2. The loaded organic phase was subjected to 3-stage countercurrent back-extraction using a back-extraction agent at a flow ratio of 15 / 1. The back-extraction organic phase was then saponified and returned to the extraction stage. The mixing time for both extraction and back-extraction was 5 min, and the temperature was 40℃. After the extraction and back-extraction reached equilibrium, the pH value of the aqueous phase at each stage of the extraction stage was between 1.5 and 2.0. Table 2 shows the experimental results after the extraction-back-extraction reached equilibrium.

[0106] Table 3 shows that the extraction rates of nickel and cobalt reached 99.35% and 98.72%, respectively; the concentrations of nickel and cobalt in the back-extraction solution reached 95.67 g / L and 9.29 g / L, respectively; and the enrichment factors of nickel and cobalt reached 29.80 and 29.62, respectively. The impurity ion Fe in the back-extraction solution... 3+ Al 3+ Cr 3 + Mn 2+ Mg 2+ Ca 2+ The concentrations were only 1.50 g / L, 0.90 g / L, 0.06 g / L, 0.30 g / L, 3.00 g / L and 0.06 g / L, respectively, and the removal rates were as high as 98.39%, 99.13%, 99.17%, 98.28%, 99.67% and 99.57%, respectively, indicating that the enrichment and impurity removal effect of nickel and cobalt was good.

[0107]

[0108] Example 6

[0109] Aqueous phase solution: Sulfuric acid leaching solution containing nickel electroplating sludge, with Ni 10.25 g / L, Fe 4.12 g / L, Al 2.09 g / L, Cr 7.75 g / L, Mg 0.756 g / L, Ca 0.453 g / L, and pH value of 1.5.

[0110] Organic phase: prepared from compound APDPA-3, DNSSA and diluent, wherein compound APDPA-1 is 0.1 mol / L, DNSSA is 0.1 mol / L, and the diluent is a mixed solvent of nonylphenol and sulfonated kerosene in a volume ratio of 1:3.

[0111] Back-extraction agent: 2.0 mol / L H2SO4 aqueous solution

[0112] Detergent: 0.1 mol / L H2SO4 aqueous solution

[0113] Extraction and separation operation: Before extraction, the organic phase was saponified using a 10 mol / L ammonia solution as the saponifying agent, with a saponification rate of 90% (based on NSA of the compound). The saponified organic phase and aqueous phase were subjected to 4-stage countercurrent extraction at a flow ratio of O / A = 5 / 1. The loaded organic phase was then subjected to 2-stage countercurrent washing at a flow ratio of O / A = 50 / 1. The aqueous phase generated from the washing was incorporated into the extraction feed. The washed organic phase was then subjected to 10-stage countercurrent back-extraction using a back-extraction agent at a flow ratio of 30 / 1. The back-extraction organic phase was then saponified and returned to the extraction stage. The mixing time for both extraction and back-extraction was 5 min, and the temperature was 40℃. After the extraction and back-extraction reached equilibrium, the pH value of the aqueous phase at each stage of the extraction stage was between 1.5 and 2.0. Table 3 shows the experimental results after the extraction-back-extraction reached equilibrium.

[0114] Table 4 shows that the nickel extraction rate reached 99.70%, the nickel concentration in the back-extraction solution reached 61.6 g / L, and the nickel enrichment factor was 5.98. 3+ Al 3+ Cr 3+ Mg 2+ Ca 2+ The removal rates were 99.55%, 99.36%, 99.76%, 99.87% and 99.41%, respectively.

[0115]

[0116] Example 7

[0117] Aqueous phase feed solution: Same as in Example 6.

[0118] Organic phase: prepared from compound APDPA-1, DNSSA and diluent, wherein compound APDPA-1 is 0.1 mol / L, DNSSA is 0.4 mol / L, and the diluent is a mixed solvent of n-octanol and sulfonated kerosene in a volume ratio of 1:3.

[0119] Back-extraction agent: 0.25 mol / L H2SO4 aqueous solution

[0120] Detergent: 0.1 mol / L H2SO4 aqueous solution

[0121] Extraction and separation operation: Before extraction, the organic phase was saponified using a 10 mol / L ammonia solution as the saponifying agent, with a saponification rate of 90% (based on NSA of the compound). The saponified organic phase and aqueous phase were subjected to two stages of countercurrent extraction at a flow ratio of O / A = 1 / 1. The loaded organic phase was then subjected to five stages of countercurrent washing at a flow ratio of O / A = 10 / 1. The resulting aqueous phase was incorporated into the extraction feed. The washed organic phase was then subjected to six stages of countercurrent back-extraction using a back-extraction agent at a flow ratio of 1 / 1. The back-extraction organic phase was saponified and returned to the extraction stage. The mixing time for both extraction and back-extraction was 5 min, and the temperature was 50℃. After extraction and back-extraction reached equilibrium, the pH of the aqueous phase at each stage of the extraction stage was between 1.5 and 2.0. Table 5 shows the experimental results after extraction-back-extraction equilibrium was reached.

[0122] Table 5 shows that the extraction rate of nickel reached 99.04%, and Fe... 3+ Al 3+ Cr 3+ Mg 2+ Ca 2+ The removal rates were 98.24%, 97.29%, 98.63%, 98.93% and 98.44%, respectively.

[0123]

[0124] Example 8

[0125] Aqueous phase solution: Sulfuric acid leaching solution of copper-cobalt ore after copper removal by extraction, containing Co 1.71 g / L, Fe 2.46 g / L, Al 1.85 g / L, Mn 2.28 g / L, Mg 5.64 g / L, Ca 0.345 g / L, and pH 1.5.

[0126] Organic phase: prepared from compound APDPA-1, didecylnaphthalenesulfonic acid, and diluent, wherein compound APDPA-1 is 0.1 mol / L, didecylnaphthalenesulfonic acid is 0.1 mol / L, and the diluent is sulfonated kerosene.

[0127] Back-extraction agent: 2.0 mol / L H2SO4 aqueous solution

[0128] Detergent: 0.1 mol / L H2SO4 aqueous solution

[0129] Extraction and separation operation: Before extraction, the organic phase was saponified using a 10 mol / L potassium hydroxide solution, with a saponification rate of 80% (based on NSA of the compound). The saponified organic phase and aqueous feed were subjected to 10 stages of countercurrent extraction at a flow ratio O / A = 1 / 1. The loaded organic phase was then subjected to 4 stages of countercurrent washing at a flow ratio O / A = 20 / 1, and the resulting aqueous phase was incorporated into the extraction feed. The washed organic phase was then subjected to 5 stages of countercurrent back-extraction using a back-extraction agent at a flow ratio of 10 / 1. The back-extraction organic phase was then saponified and returned to the extraction stage. The mixing time for both extraction and back-extraction was 5 min, and the temperature was 20℃. After extraction and back-extraction reached equilibrium, the pH value of the aqueous phase at each stage of the extraction stage was between 1.5 and 2.0. Table 6 shows the experimental results after extraction-back-extraction equilibrium was reached.

[0130] Table 6 shows that the cobalt extraction rate reached 99.23%, the cobalt concentration in the back-extraction solution reached 50.9 g / L, the cobalt enrichment factor reached 29.77, and the Fe... 3+ Al 3+ Mn 2+ Mg 2+ Ca 2+ The removal rates were 99.79%, 99.56%, 99.21%, 99.75% and 99.80%, respectively.

[0131]

[0132] Example 9

[0133] Aqueous phase feed solution: hydrochloric acid leachate of waste petroleum hydrogenation catalyst, containing Ni 3.25 g / L, Fe 0.178 g / L, Al 32.5 g / L, and pH 3.01.

[0134] Organic phase: prepared from compound APDPA-1, DNSSA and diluent, wherein compound APDPA-1 is 0.1 mol / L, DNSSA is 0.2 mol / L and sulfonated kerosene is the diluent.

[0135] Back-extraction agent: 5.0 mol / L HCl aqueous solution

[0136] Detergent: 0.2 mol / L HCl aqueous solution

[0137] Extraction and separation operation: The organic phase and aqueous phase feed solution were subjected to 4-stage countercurrent extraction at a flow ratio O / A = 1 / 1.5. The loaded organic phase was subjected to 3-stage countercurrent washing at a flow ratio O / A = 10 / 1. The aqueous phase generated from washing was incorporated into the extraction feed solution. After washing, the organic phase was subjected to 5-stage countercurrent back-extraction using a back-extraction agent at a flow ratio of 25 / 1. The organic phase after back-extraction was directly returned to the extraction stage. The mixing time for both extraction and back-extraction was 5 min, and the temperature was 30℃. After the extraction and back-extraction reached equilibrium, the pH value of the aqueous phase at each stage of the extraction stage was between 2.0 and 2.5. Table 7 shows the experimental results after the extraction-back-extraction equilibrium was reached.

[0138] Table 7 shows that the nickel extraction rate reached 99.90%, the nickel concentration in the back-extraction solution reached 121.3 g / L, the nickel enrichment factor reached 37.77, and the Fe... 3+ Al 3+ Mg 2+ Ca 2+ The removal rates were 99.56%, 99.98%, 99.87% and 99.93%, respectively.

[0139]

[0140] Example 10

[0141] Aqueous phase solution: Nitric acid leaching solution of lateritic nickel ore, containing Ni 4.32 g / L, Co 0.384 g / L, Fe 4.13 g / L, Al 2.31 g / L, Cr 0.542 g / L, Mn 0.523 g / L, Mg 27.3 g / L, Ca 1.24 g / L, with a pH of 1.8.

[0142] Organic phase: prepared from compound APDPA-2, DNSSA and diluent, wherein compound APDPA-2 is 0.25 mol / L, DNSSA is 0.25 mol / L, and the diluent is a mixture of octanol and No. 260 solvent oil in a volume ratio of 1:1.

[0143] Back-extraction agent: 4.0 mol / L HNO3 aqueous solution

[0144] Detergent: 0.2 mol / L HNO3 aqueous solution

[0145] Extraction and separation operation: Before extraction, the organic phase was saponified using a 10 mol / L NaOH solution, with a saponification rate of 70% (based on NSA of the compound). The saponified organic phase and aqueous feed were subjected to 5 stages of countercurrent extraction at a flow ratio of O / A = 1 / 1. The loaded organic phase was then subjected to 5 stages of countercurrent washing at a flow ratio of O / A = 10 / 1. The aqueous phase generated from the washing was incorporated into the extraction feed. The washed organic phase was then subjected to 3 stages of countercurrent back-extraction using a back-extraction agent at a flow ratio of 25 / 1. The back-extraction organic phase was saponified and returned to the extraction stage. The mixing time for both extraction and back-extraction was 5 min, and the temperature was 30℃. After the extraction and back-extraction reached equilibrium, the pH value of the aqueous phase at each stage of the extraction stage was between 1.5 and 2.0. Table 8 shows the experimental results after the extraction-back-extraction reached equilibrium.

[0146] Table 8 shows that the extraction rates of nickel and cobalt reached 99.62% and 98.71%, respectively; the concentrations of nickel and cobalt in the back-extraction solution reached 107.6 g / L and 9.57 g / L, respectively; and the enrichment factors of nickel and cobalt reached 24.9 and 24.93, respectively. 3+ Al 3+ Cr 3+ Mn 2+ Mg 2+ Ca 2+ The removal rates were 99.88%, 99.52%, 99.85%, 99.90%, 99.97% and 99.80%, respectively.

[0147]

[0148] Example 11

[0149] Aqueous feed solution: Magnesium sulfate solution containing small amounts of nickel and cobalt generated during the extraction and separation of nickel, cobalt and magnesium by P507, with Ni 1.36 g / L, Co 1.27 g / L, Mg 25.9 g / L and pH value of 6.20.

[0150] Organic phase: prepared from compound APDPA-2, DNSSA and diluent, wherein compound APDPA-2 is 0.25 mol / L, DNSSA is 0.25 mol / L, and the diluent is a mixture of octanol and No. 260 solvent oil in a volume ratio of 1:1.

[0151] Back-extraction agent: 3.0 mol / L H2SO4 aqueous solution

[0152] Detergent: 0.1 mol / L H2SO4 aqueous solution

[0153] Extraction and separation operation: Before extraction, the organic phase was saponified using a 1 mol / L MgHCO3 solution, with a saponification rate of 70% (based on NSA of the compound). The saponified organic phase and aqueous feed were subjected to 5 stages of countercurrent extraction at a flow ratio of O / A = 1 / 2. The loaded organic phase was then subjected to 5 stages of countercurrent washing at a flow ratio of O / A = 25 / 1. The aqueous phase generated from the washing was incorporated into the extraction feed. The washed organic phase was then subjected to 3 stages of countercurrent back-extraction using a back-extraction agent at a flow ratio of 25 / 1. The back-extraction organic phase was saponified and returned to the extraction stage. The mixing time for both extraction and back-extraction was 5 min, and the temperature was 30℃. After the extraction and back-extraction reached equilibrium, the pH value of the aqueous phase at each stage of the extraction stage was between 3.0 and 4.0. Table 9 shows the experimental results after the extraction-back-extraction reached equilibrium.

[0154] Table 9 shows that the extraction rates of nickel and cobalt reached 99.62% and 98.91%, respectively; the concentrations of nickel and cobalt in the back-extraction solution reached 68.0 g / L and 63.4 g / L, respectively; and the enrichment factors of nickel and cobalt reached 49.98 and 49.92, respectively. 2+ The removal rate reached 99.91%.

[0155]

[0156] Example 12

[0157] This section aims to characterize the structure of the organic phase loaded with nickel / cobalt using Fourier transform infrared spectroscopy (FT-IR) to verify: (1) whether compound APDPA is related to Ni 2+ / Co 2+ Coordination occurs; (2) Whether NSA participates in the formation of ion-pair type extracts. 5 g / L sulfate aqueous solutions of nickel and cobalt were prepared as aqueous phases. The initial pH of the feed solution was adjusted using 2.5 mol / L sulfuric acid and 2.5 mol / L sodium hydroxide to control the pH of the feed solution to 2.5. The composition of the organic phase was 0.2 mol / L APDPA-1 + 0.2 mol / L NSA + ethyl acetate, with a ratio (O / A) of 1 / 2. The temperature was 40℃, the shaking time was 5 min, and the contact was repeated 5 times. After phase separation, the organic phase was separated, and the ethyl acetate in the organic phase was evaporated to obtain the supported organic phase. Its coordination structure was analyzed by FT-IR, as follows: Figure 3 As shown in the figure. Infrared spectroscopy shows that the C≡N stretching vibration after extraction decreased from 1597.32 cm⁻¹. -1 Blue shifted to 1608.21cm -1 This indicates that the N atom participates in coordination; the S=O absorption is 1044.79 cm⁻¹. -1 Redshifted to 1025.50cm -1 This indicates that the anion and cation undergo ion association. The above results collectively confirm that the mechanism of action of the synergistic extraction system of this invention is a dual-ligand synergistic coordination mode.

[0158] The above description is merely a preferred embodiment of the present invention, and the scope of protection of the present invention is not limited to the above embodiments. For those skilled in the art, improvements and modifications obtained without departing from the inventive concept should also be considered within the scope of protection of the present invention.

Claims

1. A synergistic extractant, characterized in that: It contains the compounds APDPA and NSA; The compound APDPA is at least one of the compounds in Formula 1; ； Formula 1 The compound NSA is at least one of the compounds in formula 2: ； Formula 2 in, R1 is a C1~C9 alkyl group; R2 is a C2~C4 alkane chain; R3 and R4 are independently selected from C6~C 12 Alkyl groups; M is a cation used to balance the charge, and M can be one of hydrogen ion, ammonium ion, magnesium ion, or alkali metal ion. n is the valence number of M.

2. The synergistic extractant according to claim 1, characterized in that: The molar ratio of the compound APDPA to the compound NSA is 1:1 to 1:

4.

3. A method for selectively extracting nickel and cobalt from an acidic, impure solution using a synergistic extractant, characterized in that: The organic phase containing a synergistic extractant is subjected to single-stage or multi-stage countercurrent extraction with an acidic aqueous solution containing nickel and / or cobalt. The resulting loaded organic phase is then subjected to single-stage or multi-stage countercurrent back-extraction with an aqueous solution of inorganic acid, either directly or after washing, to obtain a solution containing nickel and / or cobalt. The organic phase after back-extraction is then returned to the extraction process, either directly or after saponification. The synergistic extractant is the synergistic extractant according to claim 1 or 2; The organic phase consists of a synergistic extractant and an organic diluent. The concentration of compound NSA in the synergistic extractant is 0.1–0.4 mol / L, and the molar ratio of compound APDPA to compound NSA is 1:1–1:

4. The organic diluent is sulfonated kerosene, No. 260 solvent oil, Escaid 110, or C6–C4 solvent. 13 aliphatic monohydric alcohols, C8~C 12 At least one of alkylphenols and trialkyl phosphates; The impurity ions in the acidic nickel- and / or cobalt-containing aqueous solution include at least one impurity metal cation selected from iron, aluminum, manganese, magnesium, calcium, and chromium ions, with a pH value of 1.0 to 7.

0. The inorganic acid aqueous solution includes at least one of sulfuric acid, hydrochloric acid, and nitric acid aqueous solution, whose H+ + The concentration is between 0.5 and 6.0 mol / L; During the extraction process, the volumetric flow rate ratio of the organic phase to the aqueous phase is 1 / 5 to 10 / 1, and the pH value of the equilibrium aqueous phase is controlled at 1.0 to 4.

0. During the back-extraction process, the volumetric flow rate ratio of the organic phase to the aqueous phase is 1 / 1 to 30 / 1.

4. The method according to claim 3, characterized in that: The molar ratio of compound APDPA to compound NSA is 1:1 to 1:

2.

5. The method according to claim 3, characterized in that: During the extraction process, the pH value of the equilibrium aqueous phase is controlled at 1.5~2.

0.

6. The method according to claim 3, characterized in that: The extraction stages range from 1 to 10.

7. The method according to claim 3, characterized in that: The number of stages of back-extraction is 1 to 10.

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