Organic acid composition as well as preparation method and use method thereof

Abstract

The invention discloses an organic acid composition as well as a preparation method and a use method thereof. The organic acid composition is used for dissolving out cobalt ions. The organic acid composition comprises the following components in percentage by mass: 20%-40% of oxalic acid, 15%-30% of tartaric acid, 10%-25% of malic acid, 10%-20% of citric acid and the balance of water. An acid leaching system is composed of oxalic acid, tartaric acid, malic acid and citric acid which have the synergistic effect, the method has the advantages of being scientific and reasonable in design, safe and easy and convenient to operate, high in cobalt dissolution rate, small in equipment corrosion and the like, efficient cobalt dissolution can be achieved, the cobalt dissolution rate can reach 90% or above, and meanwhile the method has the advantages of being environmentally friendly, easy and convenient to process, small in equipment corrosion, low in cost and the like; good industrial application prospects are realized.

Description

Technical Field

[0001] The present invention relates to the technical field of waste cemented carbide resource recovery, and more specifically, to an organic acid composition and a preparation method and a use method thereof. Background Art

[0002] Cobalt is an important strategic resource, widely used in batteries, magnetic materials, catalysts and other fields. With the rapid development of my country's new energy industry, the demand for cobalt resources is increasing. At present, the traditional cobalt dissolution methods mainly include inorganic acid leaching and single organic acid leaching.

[0003] Inorganic acid leaching methods such as hydrochloric acid leaching and sulfuric acid leaching have high dissolution efficiency, but they are highly corrosive, so special corrosion-resistant materials are needed to manufacture equipment, which has high requirements for equipment and increases equipment cost and maintenance difficulty. At the same time, the inorganic acid leaching method will produce a large amount of acidic wastewater and waste gas during the leaching process, which contain pollutants such as heavy metal ions. If not strictly treated, it will cause serious pollution to the environment. For example, the wastewater generated after sulfuric acid leaching of cobalt contains a large amount of sulfate ions and cobalt ions. Treating these wastewaters requires a lot of money and energy for post-treatment.

[0004] Although the single organic acid leaching method reduces the corrosiveness and environmental pollution to a certain extent, the single organic acid has limited dissolution capacity for cobalt. It requires a long leaching time (5h~8h) and a high temperature to achieve a certain dissolution effect. The dissolution efficiency is low, which increases energy consumption and production costs. For example, when citric acid is used to leach cobalt, the dissolution rate is slow at room temperature. It is necessary to increase the temperature to a certain degree and extend the leaching time to obtain a good dissolution rate. This not only consumes a lot of energy, but also reduces production efficiency, making it difficult to meet the needs of industrial production. At the same time, the dissolution effect of different single organic acids on cobalt is greatly affected by factors such as the existence form of cobalt and the composition of materials, and the scope of application is relatively narrow. For example, for some cobalt ores or waste battery materials with complex mineral structures, single organic acids cannot effectively dissolve cobalt, and the scope of application is limited. Summary of the invention

[0005] The purpose of the present invention is to overcome the above-mentioned defects of the prior art, and to provide an organic acid composition and a preparation method and a use method thereof, wherein an acid leaching system is composed of oxalic acid, tartaric acid, malic acid and citric acid having synergistic effects, and the present invention has the advantages of scientific and reasonable design, safe and simple operation, high cobalt dissolution rate, low equipment corrosion, etc., and can achieve efficient dissolution of cobalt, with a cobalt dissolution rate of more than 90%. At the same time, the present invention has the advantages of being green and environmentally friendly, simple in process, low in corrosion to equipment, low in cost, etc., and has good industrial application prospects.

[0006] To achieve the above object, the technical solution of the present invention is as follows:

[0007] An organic acid composition is used for dissolving cobalt ions; the organic acid composition comprises the following components in percentage by mass: 20% to 40% of oxalic acid, 15% to 30% of tartaric acid, 10% to 25% of malic acid, 10% to 20% of citric acid, and the balance is water.

[0008] The present invention also discloses a method for preparing the organic acid composition as described above, comprising the following steps: mixing oxalic acid, tartaric acid, malic acid and citric acid with water at 40° C. to 70° C. to obtain the organic acid composition.

[0009] The present invention also discloses an organic acid composition as described above, or a method for using the organic acid composition prepared by the preparation method as described above, comprising the following steps: mixing a cobalt-containing material with the organic acid composition for acid leaching, and filtering to obtain a cobalt-containing eluate.

[0010] Implementing the embodiments of the present invention will have the following beneficial effects:

[0011] 1. The present invention combines actual experiments to optimize the specific composition and ratio of the organic acid composition. The organic acid composition composed of oxalic acid, tartaric acid, malic acid and citric acid with synergistic effects has high dissolution performance. Compared with the single organic acid leaching method, the dissolution rate is greatly improved, and the cobalt dissolution rate can be increased by 20% to 50% under the same conditions. For example, for the positive electrode material of waste batteries, the dissolution rate of the composition of the present invention can reach more than 90%, which is 70% higher than the dissolution rate of single citric acid.

[0012] 2. The organic acid composition of the present invention can shorten the reaction time. Compared with the single organic acid leaching method, it can greatly shorten the reaction time from 5h to 8h to 1h to 5h.

[0013] 3. Compared with the inorganic acid leaching method, the organic acid composition of the present invention has less corrosion to equipment, reduces equipment cost and safety risks. At the same time, the composition of the present invention adopts easily degradable organic acids, is environmentally friendly, has low difficulty in wastewater and waste gas treatment, reduces environmental pollution, and meets environmental protection requirements.

[0014] 4. The organic acid composition of the present invention has high dissolution efficiency, shortens reaction time, and reduces energy consumption by 20% to 30%. At the same time, organic acids such as oxalic acid are common and low in cost, simple to prepare, and are conducive to large-scale production, thereby reducing overall costs.

[0015] 5. The organic acid composition of the present invention has wide applicability and has a good dissolution effect on waste battery positive electrode materials, cobalt ores, cobalt-containing alloys, etc.

[0016] 6. The organic acid composition of the present invention can adapt to different production processes and operating conditions, with flexible parameter adjustment and strong operability. DETAILED DESCRIPTION

[0017] The present invention is further described below in conjunction with specific embodiments, but the present invention is not limited in any way.

[0018] The invention discloses an organic acid composition, which is used for dissolving cobalt ions. The organic acid composition comprises the following components in percentage by mass: 20% to 40% of oxalic acid, 15% to 30% of tartaric acid, 10% to 25% of malic acid, 10% to 20% of citric acid, and the balance is water.

[0019] Specifically, the organic acid composition disclosed in the present invention produces a synergistic effect after reasonable proportioning, so that cobalt can be efficiently dissolved. Among them: the oxalic acid in the system has a strong complexing ability, can form a stable complex with cobalt ions, and promote the dissolution of cobalt; tartaric acid can adjust the acidity and complexing properties of the solution, and synergize with oxalic acid to improve the dissolution efficiency of cobalt; malic acid has certain reducing and buffering properties, which helps to maintain the stability of the solution and promote the dissolution of cobalt; citric acid is a good complexing agent and buffer, which can form a variety of complexes with cobalt ions and enhance the dissolution ability of the composition for cobalt.

[0020] Specifically, the organic acid composition of the present invention comprises the following reaction principles in dissolving cobalt:

[0021] 1. Principle of complexation reaction

[0022] Oxalic acid plays an important role in the complexation of the composition. Oxalate ion (C2O4 2- ) can react with cobalt ions (Co 2+ or Co 3+ ) form a stable complex. For example, oxalate ions and divalent cobalt ions can form [Co(C2O4) n ] (2-2n) (n=1, 2, etc.) type complexes allow cobalt ions to separate from the lattice or chemical bonds of the cobalt-containing material and enter the solution phase.

[0023] Tartaric acid molecules contain multiple hydroxyl and carboxyl functional groups, which can react with cobalt ions. The spatial structure of tartaric acid ions is conducive to forming a three-dimensional complex with cobalt ions, such as forming a complex similar to [Co(C4H4O6) m ] (2-2m) The complex of tartaric acid cooperates with oxalic acid to enhance the solubility of cobalt ions.

[0024] Malic acid also has carboxyl and hydroxyl groups, which can form complexes with cobalt ions. Its presence can adjust the complex balance of cobalt ions in the solution. The complexes formed are [Co(C4H6O5) k ] (2-2k) (k = 1, 2, etc.) helps stabilize the cobalt ions in the solution and prevent them from re-precipitating.

[0025] Citric acid is a strong complexing agent. Its three carboxyl groups and one hydroxyl group can form a variety of complexes with cobalt ions. For example, citrate ions and cobalt ions may form [Co(C6H5O7) j ] (2-2j) The formation of these complexes promotes the dissolution of cobalt from cobalt-containing materials, and due to the buffering properties of citric acid, the pH of the solution remains stable within a certain range, which is conducive to the continuous complexation reaction.

[0026] 2. Acid dissolution principle

[0027] Oxalic acid, tartaric acid, malic acid, and citric acid are all organic acids that partially ionize in solution, releasing hydrogen ions (H + ). For example, the ionization equation of oxalic acid is These hydrogen ions can react with metal oxides or other compounds on the surface of the cobalt-containing material.

[0028] Taking lithium cobalt oxide (LiCoO2) in the cathode material of waste lithium-ion batteries as an example, hydrogen ions can react with LiCoO2 and destroy its crystal structure. The possible reaction process is 2H + +LiCoO2→Li +

[0029] +CoOOH, the subsequently generated CoOOH can further react with organic acid ions to promote the dissolution of cobalt. For cobalt-containing materials such as cobalt ores, the hydrogen ions generated by the ionization of organic acids can also react with the metal-sulfur bonds on the surface of the cobalt minerals (such as cobaltite CoAsS), making it easier for cobalt ions to be released and then dissolved by organic acid ions.

[0030] 3. Synergistic Principle

[0031] There is a synergistic effect between various organic acids. For example, tartaric acid and malic acid can adjust the acidity and buffering properties of the solution. When oxalic acid and citric acid are complexed with cobalt ions in large quantities, the pH of the solution may change. Tartaric acid and malic acid can maintain the pH value of the solution to a certain extent, ensuring the optimal conditions for the complexation reaction.

[0032] From the perspective of complexation, the complexes formed by different organic acids have different spatial structures and stabilities. They can complement each other and form a "surrounding" complexation effect on cobalt ions. For example, the simple bidentate complex formed by oxalic acid and the multidentate complex formed by citric acid can act on cobalt ions at the same time, making the stability of cobalt ions in the solution higher, thereby more effectively dissolving from the cobalt-containing material. This synergistic effect makes the overall cobalt dissolution efficiency of the organic acid composition much higher than the dissolution efficiency of a single organic acid.

[0033] Specifically, by further optimizing and limiting the ratio of the components in the organic acid composition of the present invention, the dosage of each component can be specifically adjusted and controlled, thereby achieving a better synergistic effect.

[0034] In a specific embodiment, the mass ratio of oxalic acid, tartaric acid, malic acid and citric acid is (20-30):(15-23):(15-18):(10-16).

[0035] In one embodiment, the pH of the organic acid composition is 1-4.

[0036] In one embodiment, the cobalt ions include divalent cobalt ions and / or trivalent cobalt ions.

[0037] The present invention discloses a method for preparing an organic acid composition according to any embodiment of the present invention, comprising the following steps: dissolving oxalic acid, tartaric acid, malic acid and citric acid in water to obtain the organic acid composition.

[0038] In a specific embodiment, the preparation method specifically comprises: weighing oxalic acid, tartaric acid, malic acid and citric acid according to the above ratio, and adding them into an appropriate amount of deionized water in sequence, and fully dissolving them under stirring conditions. The stirring speed is controlled at 200 rpm to 500 rpm, and the stirring time is 30 min to 60 min, until a uniform and transparent solution is obtained, thereby obtaining an organic acid composition.

[0039] The present invention discloses an organic acid composition according to any embodiment of the present invention, or a method for using the organic acid composition prepared by the preparation method according to any embodiment of the present invention, the application comprising: mixing a cobalt-containing material with the organic acid composition for acid leaching, and filtering to obtain a cobalt-containing dissolution solution.

[0040] In a specific embodiment, the acid leaching temperature is 40° C. to 80° C.; the acid leaching time is 1 h to 5 h, preferably 3 h.

[0041] In a specific embodiment, the solid-liquid ratio of the cobalt-containing material to the organic acid composition is 1:(5-10).

[0042] In a specific embodiment, the mixing is performed by stirring at a speed of 300 rpm to 600 rpm.

[0043] In a specific embodiment, after the acid leaching reaction is completed, the cobalt-containing dissolution solution and the leaching residue can be separated by filtration, centrifugation, etc., and the cobalt-containing dissolution solution can be further subjected to subsequent cobalt recovery treatment.

[0044] In a specific embodiment, the cobalt-containing material includes one or more of a positive electrode material of a lithium-ion battery, a cobalt-containing ore, and a cobalt-containing alloy.

[0045] In a specific embodiment, the positive electrode material of the lithium-ion battery includes a positive electrode material of a lithium cobalt oxide battery.

[0046] In one embodiment, the cobalt-containing ore includes cobaltite.

[0047] In one specific embodiment, the cobalt-containing alloy includes a cobalt-nickel alloy.

[0048] In a specific embodiment, the mass fraction of cobalt in the cobalt-containing material is 10% to 80%.

[0049] The following are specific embodiments

[0050] Example 1

[0051] The organic acid composition of this embodiment includes the following components in percentage by mass: 30% oxalic acid, 25% tartaric acid, 20% malic acid, and 25% citric acid, and the pH value is 2.

[0052] The method for preparing the organic acid composition of this embodiment comprises the following steps: weighing oxalic acid, tartaric acid, malic acid and citric acid according to the above ratio, and sequentially adding them into an appropriate amount of deionized water, and fully dissolving them under stirring conditions. The stirring speed is controlled at 200 rpm, and the stirring time is 40 minutes, until a uniform and transparent solution is obtained.

[0053] The organic acid composition of this embodiment is used to dissolve cobalt from the positive electrode material of waste lithium-ion batteries. The specific method includes: crushing the positive electrode material of waste cobalt-acid lithium batteries to a particle size of 0.1mm to 0.5mm, weighing 10g of the crushed positive electrode material, and adding it to a 250mL reactor containing 80mL of the organic acid composition solution according to a solid-liquid ratio of 1:8 (g / mL). The reactor is placed in a constant temperature water bath, heated to 60°C, and stirred at a speed of 400 rpm. After the reaction is carried out for 3h, heating and stirring are stopped. The reacted material is filtered by vacuum filtration to obtain a cobalt-containing solution and leached slag.

[0054] The concentration of cobalt in the cobalt-containing solution was determined by atomic absorption spectroscopy, and the dissolution rate of cobalt was calculated. The concentration of cobalt in the cobalt-containing solution was determined to be 1.85 g / L, and the dissolution rate of cobalt was calculated to be 92.5% based on the amount of cobalt initially added.

[0055] Example 2

[0056] The organic acid composition of this embodiment includes the following components in percentage by mass: 25% oxalic acid, 30% tartaric acid, 15% malic acid, and 30% citric acid, and the pH value is 3.

[0057] The method for preparing the organic acid composition of this embodiment comprises the following steps: weighing oxalic acid, tartaric acid, malic acid and citric acid according to the above ratio, and sequentially adding them into an appropriate amount of deionized water, and fully dissolving them under stirring conditions. The stirring speed is controlled at 300 rpm, and the stirring time is 60 min, until a uniform and transparent solution is obtained.

[0058] The organic acid composition of the present embodiment is used to dissolve cobalt from cobalt ore, and the specific method includes: crushing and grinding cobaltite to make its particle size reach -200 mesh and account for more than 80%, weighing 20g of the treated cobaltite, and adding it to a 250mL beaker containing 120mL of organic acid composition solution according to a solid-liquid ratio of 1:6 (g / mL). The beaker is placed on a magnetic stirrer, heated to 50°C, and the stirring speed is 350 rpm. After the reaction is carried out for 4h, heating and stirring are stopped. The solution and slag are separated by centrifugation (speed is 3000 rpm, and the centrifugation time is 10min) to obtain a cobalt-containing solution and leached slag.

[0059] The cobalt content in the cobalt-containing solution was determined by chemical titration (with EDTA as titrant and xylenol orange as indicator) to calculate the dissolution rate of cobalt. The concentration of cobalt in the cobalt-containing solution was determined to be 1.77 g / L, and the dissolution rate of cobalt was 88.3% based on the amount of cobalt initially added.

[0060] Example 3

[0061] The organic acid composition of this embodiment includes the following components in percentage by mass: 35% oxalic acid, 20% tartaric acid, 20% malic acid, and 25% citric acid, and the pH value is 1.

[0062] The method for preparing the organic acid composition of this embodiment comprises the following steps: weighing oxalic acid, tartaric acid, malic acid and citric acid according to the above ratio, and sequentially adding them into an appropriate amount of deionized water, and fully dissolving them under stirring conditions. The stirring speed is controlled at 300 rpm, and the stirring time is 80 min, until a uniform and transparent solution is obtained.

[0063] The organic acid composition of the present embodiment is used to dissolve cobalt from a cobalt-nickel alloy (cobalt content is 30%). The specific method includes: cutting the cobalt-nickel alloy into small pieces (side length is about 0.5cm to 1cm), weighing 15g of cobalt-containing alloy waste, and adding it to a 250mL reactor containing 105mL of organic acid composition solution according to a solid-liquid ratio of 1:7 (g / mL). The reactor is placed in a constant temperature water bath, heated to 70°C, and stirred at a stirring speed of 500 rpm. After the reaction is carried out for 2.5h, heating and stirring are stopped. The reacted material is filtered (filtered with filter paper) to obtain a cobalt-containing solution and leached residue.

[0064] The concentration of cobalt in the cobalt-containing solution was determined by inductively coupled plasma optical emission spectroscopy (ICP-OES) to calculate the dissolution rate of cobalt. The concentration of cobalt in the cobalt-containing solution was determined to be 1.36 g / L. Based on the amount of cobalt initially added, the dissolution rate of cobalt was 90.7%.

[0065] Example 4-Example 6, Comparative Examples 1-14

[0066] Compared with Example 1, the difference between Examples 4 to 6 and Comparative Examples 1 to 14 is that the components and ratios of the organic acid composition are changed. Except for the above differences, other operations are the same and will not be repeated here. The specific dosage of the organic acid composition and the dissolution rate test results are shown in Table 1 below.

[0067] Table 1 Dissolution rate of Examples 1, 4-6, Comparative Examples 1-14

[0068]

[0069] It can be seen from the results in Table 1 that at the same acid leaching time, compared with the comparative example, the dissolution rates of Examples 1-4 are greatly increased by 10% to 50%, which indicates that there is a synergistic effect between the components of the composition of the present invention.

[0070] It can also be seen from the results in Table 1 that Examples 1-4 of the present invention can achieve a dissolution rate greater than 90% at an acid leaching time of 3 hours, which is even higher than the dissolution rate of the comparative example at an acid leaching time of 8 hours.

[0071] In summary, the present invention is combined with actual experiments to optimize the specific composition and ratio of the composition, so that the composition of the present invention can achieve efficient dissolution of cobalt, and the cobalt dissolution rate can reach more than 90%. At the same time, it has the advantages of being green and environmentally friendly, simple process, less corrosion to equipment, low cost, etc., and has good industrial application prospects.

[0072] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. An organic acid composition, characterized in that The organic acid composition is used to dissolve cobalt ions in waste cemented carbide; The organic acid composition comprises the following components in percentage by mass: 20% to 40% of oxalic acid, 15% to 30% of tartaric acid, 10% to 25% of malic acid, 10% to 20% of citric acid, and the balance is water.

2. The organic acid composition according to claim 1, characterized in that The mass ratio of the oxalic acid, the tartaric acid, the malic acid and the citric acid is (20-30):(15-23):(15-18):(10-16).

3. The organic acid composition according to claim 1, characterized in that The pH of the organic acid composition is 1-4.

4. The organic acid composition according to claim 1, characterized in that The cobalt ions include divalent cobalt ions and / or trivalent cobalt ions.

5. A method for preparing the organic acid composition according to any one of claims 1 to 4, characterized in that: The following steps are involved: Oxalic acid, tartaric acid, malic acid and citric acid are mixed with water at 40° C. to 70° C. to obtain the organic acid composition.

6. A method for using the organic acid composition according to any one of claims 1 to 4, characterized in that: include: The cobalt-containing material is mixed with the organic acid composition for acid leaching, and a cobalt-containing elution solution is obtained by filtering.

7. The method of use according to claim 6, characterized in that: The acid leaching temperature is 40°C to 80°C; the acid leaching time is 1h to 5h; The solid-to-liquid ratio of the cobalt-containing material to the organic acid composition is 1:(5-10).

8. The method of use according to claim 6, characterized in that: The cobalt-containing material includes one or more of a positive electrode material of a lithium-ion battery, a cobalt-containing ore and a cobalt-containing alloy.

9. The method of use according to claim 8, characterized in that: The positive electrode materials of lithium-ion batteries include positive electrode materials of lithium cobalt oxide batteries; Cobalt-containing ores include cobaltite; Cobalt-containing alloys include cobalt-nickel alloys; The mass fraction of cobalt in the cobalt-containing material is 10% to 80%.

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