TWI626985B - Systems for separating metal ion by electrodialysis synergized complexation and method thereof - Google Patents

Abstract

The present invention provides a system for recovering metal ions by a combined reaction of electrodialysis, which comprises a raw material tank, an acid solution tank and an extraction tank. The raw material tank includes a positive electrode module, and can contain a first electrolyte containing one of at least two metal ions. The acid solution tank includes a negative electrode module and forms a potential difference with the positive electrode module, and can accommodate a second electrolyte solution including an anion corresponding to the first electrolyte solution. The extraction tank can be separated from the raw material tank and the acid liquid tank by the first cation exchange membrane and the second cation exchange membrane, respectively, and can contain a third electrolyte containing thiocyanate, and thiocyanate in the third electrolyte. The acid radical may form a complex with at least one of the at least two metal ions.

Description

System and method for recovering metal ions by coordinated complex reaction of electrodialysis

The present invention relates to a system and a method for separating metal ions, and more particularly, to a system and a method for recovering metal ions through a coordinated complex reaction through electrodialysis.

In the international market, the prices of cobalt and nickel continue to rise, and the recovery of cobalt and nickel metal continues to increase, making the recovery of cobalt and nickel the biggest technical obstacle. Because the chemical properties of cobalt-nickel metals are very similar, they often co-exist and accompany in the ore deposits. Therefore, nickel is often contained in various cobalt waste slags. Also in various special alloy materials, battery materials, and catalysts, both cobalt and nickel are often contained simultaneously, and The price of cobalt and nickel has increased sharply, and the demand for cobalt has become higher, and the content has also been depleted. Therefore, it is very important to separate cobalt and nickel, and to recover and improve the purity. At present, the separation of cobalt and nickel mainly includes chemical precipitation, solvent extraction, and flotation. Separation method, two-aqueous phase extraction, resin method, polymer-salt-water liquid-solid extraction (non-organic solvent liquid-solid extraction) method, redox method, electro-extraction method, etc. In the current separation and purification technology, most of them adopt precipitation method and solvent extraction method.

In the recovery of cobalt-nickel metals, especially the metal recovery process of lithium battery ternary (LiCoO ₂ / LiNiO ₂ / LiMn ₂ O ₄ ) lithium batteries, a solution with a roughly equivalent nickel-cobalt concentration will be generated, which will occur during the precipitation process. Co-precipitation cannot be completely separated. The solvent extraction technology has become the main industrial method for the separation of cobalt and nickel due to its advantages such as high selectivity, high recovery, simple process, continuous operation, and easy automation.

In the solvent extraction technology, the nickel-cobalt extraction and separation technology in the sulfate solution system has matured after the recent 50 and 60 years of development and has been widely used in industry. On the other hand, the chloride salt system has the characteristics of high extraction and separation coefficient of nickel and cobalt, which can back-extract calcium and magnesium with water, does not co-extract with cobalt extraction, has high chloride solution metal concentration, and has small circulation flow in the technical process. However, the limitation of this method is that the concentration of chloride ions in the solution is high, the equipment is corrosive, and the operation and control are difficult. Therefore, compared with sulfate systems, the use of chloride systems for nickel-cobalt extraction and separation cannot reach large scale. Widely used.

Flotation is another kind of ore dressing method that is most widely used. It is a method to sort ore by using the differences in the physical and chemical properties of the mineral surface. The flotation method is further divided into Oil Flotation, Chemical Flotation, IonFlotation, and Foam Fractionation by different collectors. For example, conventional literature record carrier, the technique for separation and recovery of the ternary metal battery, can be ammonium thiocyanate (SCN ^-), an aqueous solution of crystal violet and Co (Ⅱ) forming water-insoluble In the presence of salts, the precipitate of the association floats in the upper layer of the water phase and is completely separated from the water.

The conventional technology also proposes the separation of metal ions by electrodialysis (ED). This technology refers to the use of the selective permeability of anion exchange membrane and cation exchange membrane under the action of an external DC electric field to allow a part of the ions to pass through. The process of ion exchange membranes migrating to another part of the water, so that part of the water is desalinated and the other part of the water is concentrated. The characteristic of electrodialysis treatment is that it requires power consumption but does not need to consume too many chemicals. The equipment is simple and easy to operate. Electrodialysis has been applied in the continuous deionization technology (CDI) for manufacturing high-purity water, and the oil phase extractant, which is also used to extract metal ions, is then regenerated by electrodialysis and the extractant without causing oil and water pollution.

However, most separation methods are still limited to the analysis or laboratory research stage, and it is difficult to directly apply to a large number of processes in the industry. Therefore, new separation methods still need to be developed.

In summary, the inventor of the present invention researched, considered, and designed an electrodialysis cooperative error The system and method for recovering metal ions by combining reaction to improve the lack of the existing technology, and then promote the industrial implementation and utilization.

In view of the above-mentioned conventional problems, the object of the present invention is to propose a system and method for recovering metal ions by using electrodialysis in a coordinated reaction, which are used to solve the difficulty in separating metal ions with similar characteristics, and the conventional technology cannot perform separation processing Is missing.

Based on the above objective, the present invention is to provide a system for recovering metal ions in a coordinated reaction of electrodialysis, which comprises a raw material tank, an acid solution tank and an extraction tank. The raw material tank includes a positive electrode module and contains a first electrolyte containing at least two metal ions. The acid liquid tank may include a negative electrode module and form a potential difference with the positive electrode module, and the acid liquid tank may contain a second electrolytic solution containing an anion corresponding to the first electrolytic solution. The extraction tank is separated from the raw material tank and the acid liquid tank by the first cation exchange membrane and the second cation exchange membrane, respectively. The extraction tank can contain sulfur containing sulfur which can form a complex with at least one of the two metal ions. One of the third electrolytes of cyanate.

Preferably, the at least two metal ions include cobalt ions and nickel ions.

Preferably, the molar number ratio of cobalt ion to thiocyanate is between 1: 3.5 and 1: 4.5.

Preferably, the third electrolyte does not contain a flotation agent that can react with the complex.

Preferably, the system of the present invention further comprises a raw material replenishing tank, an acid replenishing tank and an extracting liquid replenishing tank which are respectively connected to the raw material tank, the acid liquid tank and the extraction tank.

Preferably, the raw material tank, the acid liquid tank, and the extraction tank can be closed tanks.

Based on the above objectives, the present invention further provides a device for recovering metal ions by the electrodialysis coordinated hybrid reaction, which comprises an ion storage tank, an acid liquid tank, and an extraction tank. The ion storage tank may include a positive electrode module, and accommodate a fourth electrolyte containing a first thiocyanate or sulfate. The acid tank may include a negative electrode mold Group to form a potential difference with the positive electrode module. The extraction tank can be separated from the ion storage tank and the acid liquid tank by the first anion exchange membrane and the second cation exchange membrane, respectively. The extraction tank can contain a fifth electrolysis containing at least two metal ions and a second thiocyanate. liquid. At least one of the two metal ions forms a complex with the second thiocyanate, and the metal ions in the fifth electrolyte that do not form a complex with the second thiocyanate can be located in the acid solution through the second cation exchange membrane. groove.

Preferably, the at least two metal ions include cobalt ions and nickel ions, and the molar ratios of the cobalt ions and nickel ions are between 1: 0.75 to 1: 1.25. The molar ratio of the second thiocyanate to the cobalt ions in the extraction tank From 1: 3.5 to 1: 4.5.

Based on the above objectives, the present invention further provides a system for recovering metal ions by a coordinated reaction of electrodialysis, which includes a first electrodialysis device, a second electrodialysis device, and a third electrodialysis device. The first electrodialysis device includes: a raw material tank including a first positive electrode module, and containing a first electrolyte containing at least two metal ions; a first acid liquid tank, which may include a first negative electrode module and the first positive electrode module Forming a potential difference and containing a second electrolytic solution containing anions corresponding to the first electrolytic solution; and a first extraction tank, which can be respectively connected to the raw material tank and the first acid liquid tank through the first cation exchange membrane and the second cation exchange membrane They are separated from each other and contain a third thiocyanate-containing third electrolyte solution that can form a complex with at least one of the at least two metal ions. The second electrodialysis device includes: a first ion storage tank, which may include a second positive electrode module, and a fourth electrolyte containing thiocyanate or sulfate; and a second acid tank, which may include a second negative electrode module A potential difference is formed with the second positive electrode module; and the second extraction tank can be separated from the first ion storage tank and the second acid liquid tank by the third anion exchange membrane and the fourth cation exchange membrane, respectively, and the second extraction tank The tank can selectively communicate with the first extraction tank, and the second extraction tank can contain a fifth electrolyte. The fifth electrolytic solution is a third electrolytic solution subjected to an electrodialysis reaction, and metal ions in which no complex is formed in the fifth electrolytic solution can be located in the second acid solution tank through the fourth cation exchange membrane. The third electrodialysis device includes: a second ion storage tank, which may include a third positive electrode module, and accommodate a sixth electrolyte containing ammonium radicals; a third acid liquid tank, which may include a third negative electrode module, and the third The positive electrode module forms a potential difference; and a back extraction tank, which can be connected to the second ion storage tank and the third acid liquid tank through the fifth cation exchange membrane and the sixth cation exchange membrane, respectively. In this segment, the back extraction tank can selectively communicate with the second extraction tank and the first extraction tank, and the back extraction tank can contain a seventh electrolyte. The seventh electrolyte is the fifth electrolyte that undergoes electrodialysis. The ammonium radical of the sixth electrolyte can release the metal ions in the complex of the seventh electrolyte through the fifth cation exchange membrane. The metal ions released by the compound can be located in the third acid tank through the sixth cation exchange membrane. The seventh electrolyte in the back extraction tank can flow to the first extraction tank as the second electrolysis when the electrodialysis back extraction reaction is completed liquid.

Based on the above objective, the present invention further provides a method for recovering metal ions, which comprises providing a system for recovering metal ions by providing a direct current voltage to electrodialysis in a coordinated reaction to separate at least two metal ions.

As mentioned above, the system and system for recovering metal ions according to the electrodialysis cooperative reaction of the present invention may have one or more of the following advantages:

(1) The present invention makes use of electrodialysis ion reaction technique to move the extractor, the extraction tank to thiocyanate (SCN ^-) and the selective formation of a particular metal ion complexes, while retaining the extraction tank, so that Other metal ions pass through the ion exchange membrane to achieve the purpose of separation. It is thus possible to separate metal ions with similar chemical or electrical properties.

(2) When the system for completing the electrodialysis coordinated hybrid reaction of the present invention is set up, subsequent extraction methods only need to apply voltage, and the operation process is simple, which is beneficial to industrial large-scale separation operation.

(3) The complete judgment method of the electrodialysis synergistic reaction of the present invention, in addition to a predetermined time or current, can also be judged based on the color change of the ionic solution, and can be used with a variety of detection methods (such as optical methods, ion electrodes Method) to perform automated reaction procedures.

(4) The implementation of the system of the electrodialysis coordinated complex reaction of the present invention can be distinguished as (i) providing metal ions from the raw material liquid, or (ii) supplying thiocyanate or ammonium ions from the raw material liquid, to achieve ( i) the purpose of enriching complex ions, (ii) purifying complex ions, or (iii) electrodialysis for the purpose of reverse extraction of metal ions. In addition, the above two methods can also provide operators with optional extraction methods (such as reverse reverse extraction should).

(5) The electrodialysis collaborative solvent extraction system uses an ion membrane to isolate the metal ion acid solution, the mixed extraction solution and the low-salt aqueous solution, so that the process can be performed in a closed membrane group, and the operating environment has low pollution.

(6) The system of the electrodialysis coordinated complex reaction of the present invention uses the separation of an ion exchange membrane, which can reduce the direct contact pollution of the extractant and other liquids. In addition, since the complex formed during extraction is a reversible reaction, the complex extract can be recycled.

In order to make the above-mentioned purpose, technical characteristics, and gain after actual implementation more obvious and easy to understand, the following will be explained in more detail with better implementation examples supplemented by corresponding diagrams.

10, 310‧‧‧ raw material tank

11,311,411,511‧‧‧Positive Module

15‧‧‧ Raw material replenishment tank

16‧‧‧ion storage tank

20, 26‧‧‧ Extraction tank

25‧‧‧ Extraction liquid replenishment tank

30‧‧‧acid tank

31, 331, 431, 531‧‧‧ negative module

35‧‧‧Acid solution tank

40‧‧‧ion exchange membrane

51, 351‧‧‧ the first cation exchange membrane

52, 62, 352‧‧‧Second cation exchange membrane

61‧‧‧The first anion exchange membrane

81, 381‧‧‧ first electrolyte

82, 382‧‧‧Second electrolyte

83, 383‧‧‧Third electrolyte

300‧‧‧The first electrodialysis device

320‧‧‧The first extraction tank

330‧‧‧The first acid tank

400‧‧‧Second electrodialysis device

410‧‧‧The first ion storage tank

420‧‧‧Second extraction tank

430‧‧‧Second acid tank

461‧‧‧The third anion exchange membrane

462‧‧‧Fourth cation exchange membrane

481‧‧‧Fourth electrolyte

482‧‧‧Fifth electrolyte

500‧‧‧Third electrodialysis device

510‧‧‧Second Ion Storage Tank

520‧‧‧back extraction tank

530‧‧‧Third acid tank

551‧‧‧Fifth cation exchange membrane

552‧‧‧sixth cation exchange membrane

581‧‧‧Sixth electrolyte

582‧‧‧Seventh electrolyte

FIG. 1 is a schematic diagram of a system for recovering metal ions according to an electrodialysis coordinated hybrid reaction according to the present invention.

FIG. 2 is a schematic diagram of a metal misconcentration enrichment system for a system for recovering metal ions by an electrodialysis coordinated hybrid reaction according to the present invention.

FIG. 3 is an effect diagram of the concentration of sodium thiocyanate as a complexing agent of the metal complex ion enrichment system according to the present invention.

Fig. 4 is a graph showing the concentration effect of ammonium thiocyanate as a complexing agent in the metal ion ion enrichment system according to the present invention. Part (A) of FIG. 4 is a graph of the extraction efficiency of cobalt and nickel with a complexing agent concentration of 1 to 4M, and part (B) of FIG. 4 is a graph of the extraction efficiency of cobalt and nickel with a complexing agent concentration of 0.1 to 0.6M. .

FIG. 5 is a temperature effect diagram of ammonium thiocyanate, a complexing agent of a metal complex ion enrichment system according to the present invention.

FIG. 6 is an effect diagram of the concentration of ammonium thiocyanate as a complexing agent of the metal complex ion enrichment system according to the present invention.

Fig. 7 is a graph showing the effect of the recovery complex and the new complex on the extraction rate of cobalt according to the metal complex ion enrichment system of the present invention.

FIG. 8 is a schematic diagram of a metal complex ion purification system of a system for recovering metal ions according to the electrodialysis coordinated complex reaction according to the present invention.

Fig. 9 is a graph showing the cobalt-nickel extraction efficiency effect of the metal ion purification system according to the present invention.

FIG. 10 is a schematic diagram of a recycling system for recovering metal ions by a coordinated hybrid reaction of electrodialysis according to the present invention.

Please refer to FIG. 1, which is a schematic diagram of a system for recovering metal ions by a coordinated complex reaction of electrodialysis according to the present invention. The figure shows a system for recovering metal ions by electrodialysis with a coordinated reaction, which includes a raw material tank 10, an extraction tank 20, and an acid liquid tank 30. The raw material tank 10 can contain a first electrolyte solution 81, the extraction tank 20 can contain a third electrolyte solution 83, and the acid solution tank 30 can contain a second electrolyte solution 82.

The extraction tank 20 is separated from each other by two kinds of ion exchange membranes 40 and liquids in the raw material tank 10 and the acid liquid tank 30. In the system, the positive electrode module 11 located in the raw material tank 10 and the negative electrode module 31 located in the acid liquid tank 30 can form a potential difference to generate ion movement. The embodiments may be provided to generate a potential difference between a current density of 0.05A / cm ² to 0.3A / cm ^2, and more preferably, the current density may be between 0.075A / cm ² to 0.2A / cm ² in.

In practice, when the system for recovering metal ions by the electrodialysis coordinated hybrid reaction of the present invention is energized, in addition to the potential difference, it will promote metal ions to pass through the exchange membrane, and the ion concentration gradient on both sides of the ion exchange membrane It also affects the permeability of metal ions. Without being bound by any specific theory, from the results of the present invention, the degree to which the metal ions pass through the ion exchange membrane under the test conditions of the present invention is caused by the concentration difference and voltage. Figures 2 and 8 of the present invention The figure and FIG. 10 also schematically illustrate the difference in the concentration of components in each tank and the direction of ion movement.

For example, in the raw material tank 10 and the extraction tank 20 on both sides of the first cation exchange membrane 51 shown in FIG. 2, the concentration of cobalt ions in the extraction tank 20 is lower than that of the raw material tank 10, and the thiocyanate in the extraction tank 20 Forms a complex with cobalt ions, so that the cobalt ions in the extraction tank 20 remain lower than the cobalt ion concentration in the raw material tank 10, most of the cobalt ions move from the raw material tank 10 to the extraction tank 20, and most of the nickel ions stay in the raw material In the tank 10, cobalt nickel ions are separated. However, the embodiment of the present invention is not limited to this. For example, according to the characteristics of the metal ions to be separated in the raw material tank 10, the potential difference can be controlled so that the first metal ions are enriched in the acid liquid tank 30 after being energized, so that the first After being energized, the two metal ions are accumulated in the extraction tank 20 and form a complex with thiocyanate, so that the third metal ions remain in the raw material tank 10 after being energized.

In practice, the system for recovering metal ions by the electrodialysis coordinated hybrid reaction of the present invention may further include a raw material replenishing tank 15, an extracting liquid replenishing tank 25 and a raw material replenishing tank 15, an extraction liquid replenishing tank 25 and The acid solution replenishes the tank 35 to perform a batch or continuous extraction process. In addition, the system can be connected in parallel or in series depending on the extraction.

In practice, the system for recovering metal ions by the electrodialysis coordinated hybrid reaction of the present invention may further include a stirring unit in the tank or a circulating stirring unit disposed outside the tank, so that the thiocyanate and the metal ions in the extraction tank 20 are completely processed. Combined reaction to improve batch extraction efficiency.

The present invention performs extraction and recovery of metal ions by using electrodialysis in conjunction with a complex reaction. According to this, unlike conventional thiocyanate and flotation agent for metal ion flotation recovery, the present invention produces a complex reaction extraction The third electrolyte in the tank may not contain these flotation agents, for example, anionic surfactants, cationic surfactants, capture agents, foaming agents, and regulators, specifically, crystal violet, ethyl Violet, cetyltrimethylammonium cation (CTMAB ⁺ ), cetylpyridine bromide, cetyltrimethyl chloride, dodecyl sulfate or potassium bromide. In addition, some of the flotation agents will cause thiocyanate to form water-insoluble ternary associations with metal ions in the aqueous solution, and the concentration of the top of the extraction tank may cause uneven mixing of the third electrolyte reactants or affect conductivity Degree or permeability of the ion exchange membrane.

The system for recovering metal ions by the electrodialysis coordinated hybrid reaction of the present invention can change the reaction in the raw material tank 10 and the extraction tank 20 according to the hybrid reaction generated in the extraction tank 20 to achieve the purpose of enriching metal ions or purifying the complex metal ions. Reagents, and the types of the two ion exchange membranes 40 are changed accordingly. However, no matter what the purpose is, it is to make the metal ions selectively react with the thiocyanate in the extraction tank 20 and retain the mixed metal ions in the extraction tank 20. Further description will be made with specific implementation. Example match description.

Please refer to FIG. 2 to FIG. 7, which show the implementation of enriching metal ions by the system for recovering metal ions by the electrodialysis cooperative reaction in the present invention.

Please refer to FIG. 2, which is a schematic diagram of a metal error ion enrichment system of a system for recovering metal ions by electrodialysis with a coordinated reaction. In the figure, the raw material tank 10, the extraction tank 20 and the acid liquid tank 30 are separated from each other by a first cation exchange membrane 51 and a second cation exchange membrane 52, and the remaining systems are arranged in a manner similar to the system shown in FIG. 1 the same. The raw material tank 10 can contain a first electrolytic solution 81 containing at least two kinds of metal ions, the acid liquid tank 30 can contain a second electrolytic solution 82 and contains anions corresponding to the first electrolytic solution 81, and the extraction tank 20 contains The third electrolyte 83 of the complexing agent, and the thiocyanate in the complexing agent can form a metal complex with at least one of the at least two metal ions.

According to this, when a DC voltage is applied to the metal ion recovery system, a small amount of metal ions (for example, nickel ions shown in FIG. 2) that are not conjugated with thiocyanate pass through the first cation exchange membrane 51, so they are mainly concentrated in In the raw material tank 10. Metal ions that can be mismatched with thiocyanate (for example, cobalt ions shown in Figure 2) are concentrated in the extraction tank 20 when they pass through the first cation exchange membrane 51. Metal ions mismatched with thiocyanate can make the The concentration of metal ions decreases, which drives the metal ions into the extraction tank 20 continuously. Finally, will The two metal ions are separated in different water tanks.

In practice, when the at least two kinds of metal ions are nickel ions and cobalt ions, in order to fully react the thiocyanate with the metal ion, the reaction concentration can be adjusted by referring to the coordination number of the metal ion and the thiocyanate. , Can make the molar ratio of cobalt ion to thiocyanate range from 1: 3.5 to 1: 4.5, and more preferably the molar ratio is 1: 4.

It has been confirmed by experiments that in addition to the concentration effect, the system has a better extraction efficiency at a temperature of 15 ° C to 30 ° C for the extraction reaction, and can be about 15 ° C to 20 ° C, but it reacts at room temperature as a whole. Does not significantly affect the extraction efficiency. In addition, the reacted complexing agent (ie, thiocyanate) can still achieve almost the same effect as the complexing agent used for the first time after regeneration with a weak base.

When the above system is used to achieve the maximum extraction rate, the separated metal ions can be taken out from the extraction tank 20 or the raw material tank 10, and used to recover specific metals with known precipitation methods, solvent back extraction, electrolytic reactions, or other similar systems. Perform the electric stripping procedure.

Please refer to FIG. 3 to FIG. 7, which are embodiments of using the electrodialysis synergistic reaction recovery system of the present invention to recover metal ions for separating nickel and cobalt ions, and comparing nickel and cobalt under different conditions. The main experimental conditions and flow of the ion extraction effect are as follows:

(1) Configure different proportions of cobalt powder and nickel powder, add 500mL of 0.432N sulfuric acid, and completely dissolve them with an electromagnetic stirrer as a sample of the raw material tank.

(2) at different thiocyanate (SCN ^-) as the sources of the reagents complexing agent, for example, ammonium thiocyanate (NH ₄ SCN) or sodium thiocyanate (of NaSCN), as the liquid extraction tank.

(3) Configure 1% sulfuric acid as the liquid in the acid tank.

(4) The above liquid is placed in a tank body to conduct an electric current test. The current density is 0.134 A / cm ² for 24 hours, and samples are taken at predetermined time intervals.

(5) After the experiment is completed, the samples obtained in the extraction tank are analyzed by inductively coupled plasma atomic emission spectrometry and flame atomic absorption spectrometry.

Please refer to Figure 3 and Figure 4 to compare the concentration effect of different complexing agents sodium thiocyanate and ammonium thiocyanate on the concentration of metal ions. The test conditions for this experiment are (1) dissolving cobalt powder and nickel powder in a 1: 1 molar ratio (2.5g each) in 0.432N sulfuric acid to form a 0.085M metal solution, and (2) 0.5 ~ 4M thiocyanate Sodium or 0.1 ~ 4M ammonium thiocyanate was used as the complexing agent, and the effect on the extraction rate of cobalt and nickel was analyzed after being energized for 24 hours.

As shown in Figure 3, when the complexing agent is 0.5 ~ 4M sodium thiocyanate, as the concentration of sodium thiocyanate increases, the cobalt ions do not increase significantly, but the nickel ions increase slightly. As the sodium concentration increases, the SCN ^- concentration in the extraction tank also increases, and the reaction tends to form Co (SCN) ₄ ^2- complex. Comparing part (A) of Figures 3 and 4, when the complexing agent is 1 ~ 4M ammonium thiocyanate, the extraction rate for nickel ions is smaller than for sodium thiocyanate of the same concentration, and for cobalt There is not much difference in ions, so the separation of cobalt ions and nickel ions by sodium thiocyanate is worse than that of ammonium thiocyanate. Subsequent experiments will be performed using ammonium thiocyanate.

The results in part (B) of Figure 4 also show that the increase in the concentration of ammonium thiocyanate between 0.1 and 0.4 M increases the extraction rates of cobalt and nickel ions, which may be caused by the increase in the concentration of ammonium thiocyanate. The extraction equilibrium is shifted toward the formation of the complex. When the concentration of ammonium thiocyanate is 0.4M, the separation rate can reach the maximum, and the separation rate is better than 1 ~ 4M. The reason may be that the ratio of cobalt ion and thiocyanate is 1: 4, and the concentration is 0.4M. The lower thiocyanate can be completely mismatched with cobalt ions with a total amount of 0.085M to achieve the maximum separation rate. When the concentration is 0.3M, the binding ratio of ammonium thiocyanate to cobalt ions is insufficient to form a complex with cobalt ions, which reduces the extraction rate and separation rate.

In addition, when the concentration is less than 0.5M, not only cobalt ions cannot be completely combined with thiocyanate, but also thiocyanate ions and ammonium ions in the water undergo a double hydrolysis reaction, which reduces the concentration of ammonium ions (NH ₄ ⁺ ) in the water, The concentration of NH ₃ ) increases, and ammonia (NH ₃ ) can easily form Co (NH ₃ ) _n ²⁺ positive ion complexes with cobalt ions, resulting in a decrease in extraction rate. In other words, in order to complete the reaction of 0.085M cobalt ions, the theoretical concentration of thiocyanate ions is 0.34M. In the experiments of the present invention, about 10% of thiocyanate reacts with nickel ions. The dose is between 0.374 ~ 0.400M.

Please refer to FIG. 5, which is the complex agent sulfur of the metal complex ion enrichment system according to the present invention. Temperature effect diagram of ammonium cyanate. The test conditions for this test are (1) dissolving cobalt powder and nickel powder in a 1: 1 molar ratio (2.5g each) in 0.432N sulfuric acid to form a 0.085M metal solution, and (2) using 0.4M ammonium thiocyanate. As a complexing agent, the effect of temperature change on cobalt-nickel extraction rate was analyzed after 24 hours of application of electricity. The results are shown in Figure 5. There is little difference in the performance of cobalt ions at different temperatures. Conversely, an increase in temperature will increase the extraction rate of nickel ions from 15% to 25%, and lowering the temperature is beneficial to the reaction. Therefore, in the metal ion separation strategy of the present invention, the higher the temperature, the faster the ion movement rate may be caused, so that a larger amount of nickel ions enter the mixed solution, which is disadvantageous for separation.

Please refer to FIG. 6, which is a metal ion concentration effect diagram of the metal ion ion enrichment system according to the present invention. The test conditions for this test are (1) the cobalt powder and nickel powder are 1: 4 (0.085M: 0.340M), 1: 2 (0.085M: 0.170M), 1: 1 (0.085M: 0.085M), 2 : 1 (0.170M: 0.085M), 4: 1 (0.340M: 0.085M) Molar ratio dissolved in 500mL of 0.432N sulfuric acid, (2) 0.4M ammonium thiocyanate as the complexing agent, (3) raw material tank and The volume ratio of the solution in the extraction tank is 1: 5. Part (B) of Fig. 6 is the original extraction amount diagram of part (A). From Fig. 6, it can be known that the more the proportion of the metal, the higher the extraction amount. When the molar ratio of cobalt and nickel ions is higher, When it is 1: 1, the cobalt ion and thiocyanate are completely mismatched, and a very small amount of nickel ions leak into the extraction tank, so the maximum separation rate is reached. When the molar ratio is 1: 4 and 1: 2, the molar number of nickel ions is large, and more nickel ions move to the extraction tank per unit time due to the electric field and diffusion leakage. They compete with cobalt ions for thiocyanate, and the cobalt ions are the same. The time cannot be completely matched, so the extraction rate is low. At a molar ratio of 2: 1, although cobalt ions still have enough thiocyanate to be complexed, a certain amount of nickel ions leak into the extraction tank. At a molar ratio of 4: 1, the excess cobalt ions cannot be completely combined, and some of the cobalt ions move to the cathode during electrodialysis, reducing the separation rate.

The above results show that if the system of the present invention is to be used to maximize the separation of nickel ions (Ni (II)) and cobalt ions Co (II), it is recommended that the nickel ions in the raw material tank and the thiocyanate in the extraction tank be The molar ratio is adjusted to (cobalt ion: thiocyanate) 1: 4, and the molar ratio of cobalt ion to nickel ion in the raw material tank is adjusted to 1: 1, or the nickel ion is slightly lower than the above value. In other words, the system of this case is suitable for the separation strategy to produce a sample solution with a concentration of cobalt ions and nickel ions during the metal ion recovery process. But not implemented This is a limitation, and according to the results of FIG. 6, it can be confirmed that two kinds of metal ions can also be separated under different molar ratios, while cobalt and nickel ions have a molar ratio of 1: 1. There is maximum separation rate. For solutions that cannot be completely mismatched, the metal complex ion purification system shown in Figure 8 below can be used to improve the purity of the metal complex.

Please refer to FIG. 7, which is a graph of the effect of the recovery complex and the new complex on the extraction rate of cobalt according to the metal complex ion enrichment system of the present invention. Since the complex formed during extraction is a reversible reaction, the present invention further reduces and reuses the complexing agent of the metal ion complex to compare the extraction rates of the new and old complexing agents. The test conditions for this test are (1) dissolving cobalt powder and nickel powder in a 1: 1 molar ratio (2.5g each) in 500 mL of 0.432N sulfuric acid to form a 0.085M metal solution, and (2) using 0.4M thiocyanate Ammonium is used as a complexing agent, (3) the volume ratio of the solution in the raw material tank and the extraction tank is 1: 5, and (4) the sampling and analysis are performed every 2 hours between 24 hours after the power is applied to analyze the effect of cobalt and nickel extraction rate. It can be seen from the results in FIG. 7 that after the mixed solution used for the second time is recovered, the final extraction rate in 24 hours is equivalent to that of the new mixed agent. Therefore, as long as the used complexing agent is completely processed to completely separate it from the metal ions, the original complexing agent can be used again to achieve the original effect, so multi-stage operation can be performed.

Under the above conditions, the extraction rate of cobalt can be as high as 90%, while the extraction rate of nickel is only 6%, which can achieve the separation of cobalt and nickel ions, and there will be no defects such as short working life due to the loss of the complexing agent in the process.

Please refer to FIG. 8 and FIG. 9, which are implementation examples of purifying complex ions by the system for recovering metal ions by the electrodialysis cooperative complex reaction according to the present invention.

Please refer to FIG. 8, which is a schematic diagram of a metal error ion purification system of a system for recovering metal ions by the electrodialysis cooperative reaction in the present invention. The difference from the metal ion ion enrichment system in FIG. 2 is that in the metal ion ion purification system, the raw material tank corresponding to FIG. 2 is changed to an ion storage tank 16 containing thiocyanate or sulfuric acid, and the extraction tank 26 is The first anion exchange membrane 61 and the second cation exchange membrane 62 are separated from the ion storage tank 16 and the acid liquid tank 30, respectively, and the extraction tank 20 contains at least In the second electrolyte solution 82 of two metal ions, at least one of the two metal ions forms a metal ion complex with thiocyanate. The rest of the settings are the same as in Figure 2, so they will not be described again.

When power is applied, metal ions (such as nickel ions shown in FIG. 8) that have not formed a complex will pass through the second cation exchange membrane 62 to the acid liquid tank 30 to separate the two metal ions and enrich them in the extraction tank 26 respectively. 、 In the acid tank 30.

In practice, the molar ratio of the first metal ion forming the complex in the extraction tank to the second metal ion not forming the complex may be between 1: 0.75 and 1: 1.25. If the first metal ion is cobalt ion, the molar ratio The molar ratio of thiocyanate to the first metal ion in the tank can be between 1: 3.5 and 1: 4.5, so that the thiocyanate and the cobalt ion are completely mismatched.

In practice, the metal ion purification system may further include a raw material replenishing tank (not shown) in communication with the extraction tank 20, and the arrangement thereof may be the same as that of the extracting liquid replenishing tank 26 shown in FIG. The raw material supplementation tank may contain a mixed solution of a metal thiocyanate complex. In practice, it may be a sample that has been pretreated using a metal complex ion enrichment system. The sample will be removed again in the metal complex ion purification system. Mixed metal ions, to improve the purity of metal ion complexes, to achieve the purpose of purification.

Please refer to FIG. 9, which is a graph of the extraction efficiency of cobalt and nickel in the metal ion purification system according to the present invention. The main experimental conditions are as follows:

(1) 500 mL of 0.432N sulfuric acid solution was used as the liquid in the anode ion storage tank.

(2) Dissolve each 0.5g of cobalt powder and nickel powder in 200mL of 0.432N sulfuric acid, arrange 300mL of 0.1M ammonium thiocyanate solution, and mix the two as a sample in the extraction tank.

(3) 500 mL of 0.432N sulfuric acid is used as the liquid in the cathodic acid solution tank.

(4) The above liquid is put into a tank body to conduct an electric current test. The current density is 0.134A / cm ² for 24 hours, and the sample is taken in the acid liquid tank every hour.

As can be seen from the results in Figure 9, the process of energization will promote the movement of unmatched nickel ions. To the acid solution tank, and the maximum separation rate can be reached within 11 hours to 15 hours, and longer than this time, uncomplicated cobalt ions will move to the acid solution tank. It is shown that the metal ion purification system can improve the purity of metal ion complexes in the extraction tank and achieve the purpose of purification.

In addition, in another embodiment, the liquid in the ion storage tank may also be an electrolyte containing hydrogen sulfate, such as ammonium hydrogen sulfate, which can also achieve the effect of purifying metal ion.

On the other hand, the system for recovering metal ions in the above-mentioned electrodialysis coordinated complex reaction uses an ion membrane to isolate the solution in the three tanks, so that the process can be performed in a membrane group of a closed tank. Closed loops can also be used when multiple systems are connected in series or in parallel. According to this, the direct contact pollution of the extractant and other liquids can be reduced, and the recovery and utilization characteristics of the complexing agent can be improved.

Please refer to FIG. 10, which is a schematic diagram of a circulation system for recovering metal ions according to the electrodialysis coordinated hybrid reaction according to the present invention. In the figure, the system for recovering metal ions by the combined reaction of electrodialysis is mainly composed of three electrodialysis devices connected in series. The first electrodialysis apparatus 300, the second electrodialysis apparatus 400, and the third electrodialysis apparatus 500 are respectively. Among them, the first electrodialysis device 300 is used for enriching metal ion complexes, the second electrodialysis device 400 is used for purifying the enriched metal ion complexes, and the third electrodialysis device 500 is used for electrodialysis back extraction. Metal ions forming complexes.

The raw material tank 310 of the first electrodialysis device 300 is used for containing a first electrolytic solution 381 containing at least two metal ions, and the first acid liquid tank 330 is used for containing a second electrolytic solution containing anions corresponding to the first electrolytic solution 381 Liquid 382. The first negative electrode module 331 and the first positive electrode module 311 are respectively disposed in the raw material tank 310 and the first acid liquid tank 330 to generate a potential difference. The first extraction tank 320 is separated from the raw material tank 310 and the first acid liquid tank 330 by the first cation exchange membrane 351 and the second cation exchange membrane 352, respectively. The first extraction tank 320 may contain ammonium thiocyanate. Third electrolyte 383.

The raw material tank of the second electrodialysis apparatus 400 is a first ion storage tank 410 for containing a fourth electrolyte solution 481 containing ammonium thiocyanate. The second acid liquid tank 430 can dissolve an acid electrolyte. The second positive electrode module 311 and the second negative electrode module 331 are respectively disposed in the first ion storage tank 410 and the second acid liquid tank 430 A potential difference is generated. The second extraction tank 420 is separated from the first ion storage tank 410 and the second acid liquid tank 430 by the third anion exchange membrane 461 and the fourth cation exchange membrane 462, respectively. The second extraction tank 420 can selectively communicate with the first The extraction tank 320 and the second extraction tank 420 can contain a fifth electrolyte 482, and the fifth electrolyte 482 is a third electrolyte 383 extracted by electrodialysis.

The raw material tank of the third electrodialysis apparatus 500 is a second ion storage tank 510 for containing a sixth electrolyte solution 581 (for example, ammonium carbonate in the schematic diagram) containing ammonium radicals. The third acid liquid tank 530 contains an acidic electrolyte. The third positive electrode module 311 and the third negative electrode module 331 are respectively disposed in the second ion storage tank 510 and the third acid liquid tank 530 to generate a potential difference. The back extraction tank 520 is separated from the second ion storage tank 510 and the third acid liquid tank 530 by the fifth cation exchange membrane 551 and the sixth cation exchange membrane 552, respectively. The back extraction tank 520 can selectively communicate with the first extraction tank. 320 and the second extraction tank 420 are selectively communicated with each other. The back extraction tank 520 can contain a seventh electrolyte solution 582, and the seventh electrolyte solution 582 is a fifth electrolyte solution 482 after electrodialysis reaction. The seventh electrolyte 582 in the back extraction tank 520 can flow to the first extraction tank 320 as the second electrolyte 382 when the electrodialysis back extraction reaction is completed.

Accordingly, when the first electrodialysis device 300 is energized, at least two metal ions can selectively pass through the first cation exchange membrane 351 and selectively form a complex with the thiocyanate system in the third electrolyte 383 ( Co (SCN) ₄ ^2- ) is formed.

When the second electrodialysis device 400 is powered on, metal ions (such as nickel ions) that have not formed a complex will pass through the fourth cation exchange membrane 462 to the second acid liquid tank 430, so that the two metal ions are separated and enriched in Inside the second extraction tank 420 and the second acid liquid tank 430. In other words, in the second electrodialysis device 400, the unextracted metal ions in the second extraction tank 420 are reduced by the voltage and the (nickel) ion concentration gradient of the fourth cation exchange membrane, and the second extraction tank 420 is purified. Metal ion complex in.

When the third electrodialysis device 500 is energized, the ammonium radical of the sixth electrolyte 581 can pass through the fifth cation exchange membrane 551 to release the metal ions of the complex in the seventh electrolyte 582. The released metal ions are driven by the voltage and concentration gradient to pass through the sixth cation exchange membrane 552 and are located in the third acid. 液槽 530。 Liquid tank 530. When the electrodialysis back-extraction reaction is completed, the recovered complexing agent (ammonium thiocyanate) is left in the seventh electrolyte 582. Therefore, the seventh electrolyte 582 can flow to the second electrolyte 382 and be used again.

In practice, the source of the raw material tank 310 may be a solution of approximately equal cobalt and nickel concentration produced by removing manganese ions in the metal recovery process of a ternary (LiCoO ₂ / LiNiO ₂ / LiMn ₂ O ₄ ) lithium battery. The removal of manganese ions and lithium ions from the metal solution recovered by the elementary lithium battery is a conventional technique, so it will not be repeated here. In addition, the separated cobalt and nickel ions at each separation stage can be recovered by electrolysis.

Based on the purpose of the present invention, another method for recovering metal ions is provided. The method includes the system for recovering metal ions by the above-mentioned electrodialysis coordinated complex reaction, and provides a potential difference according to the extraction procedure to achieve enrichment of metal ions. Set to different tanks.

In addition to the above embodiments, the choice of the complexing agent (ammonium thiocyanate) of the present invention can achieve the characteristics that the pH value does not need to be adjusted during the reaction, and the operation process is reduced. In addition to the predetermined time or current, the degree of reaction can also be judged according to the color change of the ionic solution, or a variety of detection methods (such as optical method, ion electrode method) can be used to perform automated reaction procedures.

The above description is exemplary only, and not restrictive. Anything that does not depart from the essence of the invention God and the scope, and the equivalent modification or change to them should be included in the scope of patent application attached.

Claims (9)

A system for recovering metal ions by an electrodialysis coordinated hybrid reaction, comprising: a raw material tank including a positive electrode module, and containing a first electrolyte solution containing at least two metal ions; an acid solution tank including a negative electrode mold Forming a potential difference with the positive electrode module and containing a second electrolyte containing an anion corresponding to the first electrolyte; and an extraction tank through a first cation exchange membrane and a second cation exchange membrane Is separated from the raw material tank and the acid liquid tank, and contains a third thiocyanate-containing third electrolyte that can form a complex with at least one of the at least two metal ions, wherein the at least two metals The ions include cobalt ions and nickel ions. The system according to item 1 of the scope of patent application, wherein the molar ratio of the cobalt ion to the thiocyanate is between 1: 3.5 and 1: 4.5. The system according to item 1 of the patent application scope, wherein the third electrolyte does not contain a flotation agent that can react with the complex. The system according to item 1 of the scope of patent application, further comprising a raw material replenishing tank, an acid replenishing tank and an extracting liquid replenishing tank which are respectively connected to the raw material tank, the acid liquid tank and the extraction tank. The system according to item 1 of the scope of patent application, wherein the raw material tank, the acid liquid tank, and the extraction tank are closed tanks. A system for recovering metal ions by an electrodialysis coordinated hybrid reaction, comprising: an ion storage tank, including a positive electrode module, and containing a fourth electrolyte containing a first thiocyanate or sulfate; an acid solution The tank includes a negative electrode module to form a potential difference with the positive electrode module; and an extraction tank, which is separated from the ion storage tank and the acid liquid tank by a first anion exchange membrane and a second cation exchange membrane, respectively. And a fifth electrolyte containing at least two metal ions and a second thiocyanate, wherein at least one of the at least two metal ions forms a complex with the second thiocyanate, the first The metal ions in the five electrolytes that do not form a complex with the second thiocyanate are located in the acid liquid tank through the second cation exchange membrane, wherein the at least two metal ions include cobalt ions and nickel ions. According to the system described in claim 6 of the application scope, the molar ratios of the cobalt ion and the nickel ion are between 1: 0.75 to 1: 1.25, and the second thiocyanate and the molar ions of the cobalt ion are in the extraction tank. The ratio is between 1: 3.5 and 1: 4.5. A system for recovering metal ions by an electrodialysis coordinated hybrid reaction includes: a first electrodialysis device including: a raw material tank, including a first positive electrode module, and containing a first containing at least two metal ions; An electrolytic solution; a first acid bath containing a first negative electrode module forming a potential difference with the first positive electrode module, and containing a second electrolytic solution containing an anion corresponding to the first electrolytic solution; and a first An extraction tank is separated from the raw material tank and the first acid liquid tank by a first cation exchange membrane and a second cation exchange membrane, respectively, and contains at least one of the at least two metal ions. A third electrolyte containing a thiocyanate that forms a complex; a second electrodialysis device including: a first ion storage tank, including a second positive electrode module, and containing a thiocyanate or A fourth electrolytic solution of sulfate; a second acid solution tank including a second negative electrode module to form a potential difference with the second positive electrode module; and a second extraction tank via a third anion exchange membrane And a fourth cation exchange membrane The second extraction tank is selectively connected to the first extraction tank, and the second extraction tank contains a fifth electrolyte, wherein, The fifth electrolytic solution is the third electrolytic solution subjected to electrodialysis reaction, and the metal ions in which the complex is not formed in the fifth electrolytic solution are located in the second acid solution tank through the fourth cation exchange membrane. And a third electrodialysis device, comprising: a second ion storage tank including a third positive electrode module and containing a sixth electrolyte solution containing ammonium radicals; a third acid liquid tank including a first Three negative electrode modules to form a potential difference with the third positive electrode module; and a back extraction tank through a fifth cation exchange membrane and a sixth cation exchange membrane with the second ion storage tank and the third acid, respectively Liquid tanks are separated from each other. The back-extraction tank is selectively connected to the first extraction tank and the second extraction tank. The back-extraction tank contains a seventh electrolyte, wherein the seventh electrolyte is Is the fifth electrolytic solution through electrodialysis, and the sixth electrolytic solution is The root system passes through the fifth cation exchange membrane to release metal ions in the complex of the seventh electrolyte, and the metal ion released from the complex is passed through the sixth cation exchange membrane to be located in the third Acid bath, the seventh electrolyte in the back extraction tank flows to the first extraction tank as the second electrolyte when the electrodialysis back extraction reaction is completed, wherein the at least two metal ions include cobalt ions and nickel ions . A method for recovering metal ions, comprising providing a direct current voltage to a system for recovering metal ions by the electrodialysis coordinated hybrid reaction as described in any one of claims 1 to 8 of the scope of patent application to separate the at least two metals ion.