Method for treating electrodeposited cobalt anode mud and anolyte

Abstract

The invention belongs to the technical field of electrodeposited cobalt, and particularly relates to a treatment method of electrodeposited cobalt anode slime and anolyte, which comprises the following steps: S1, anode slime and anolyte are obtained, the anode slime comprises Co < 3 + >, and the anolyte comprises H < + > and Co < 2 + >; s2, adding the anolyte into the anode mud to obtain reduction slurry, and adding hydrogen peroxide into the reduction slurry for reduction leaching to obtain post-reduction liquid; s3, adjusting the pH value of the reduced solution to 1.5-2.5 by using the anolyte to obtain a regenerated electrodeposition solution; according to the method, the electrodeposition anolyte and the hydrogen peroxide are used for leaching the anode mud, short-process efficient leaching is achieved, the electrodeposition anolyte is used for leaching, leach liquor obtained after lead and oil removal can serve as electrodeposition circulating liquid to be recycled, qualified electrodeposition cobalt is produced, the acidity of the anolyte is utilized, and follow-up treatment of the leach liquor is avoided.

Description

Technical Field

[0001] The present invention belongs to the technical field of electrowinning cobalt, and specifically relates to a method for treating anode mud and anode liquid in electrowinning cobalt. Background Art

[0002] In the production of electrowinning cobalt, the current anode is mainly a titanium-based anode plate, such as titanium plated with lead, ruthenium, iridium, etc. This is mainly because it has strong resistance to strong acids and a long service life; it has a low oxygen evolution potential and high electrical energy efficiency. However, the coating is prone to peeling. Especially during the cleaning operation of the anode mud, methods such as high-pressure water gun flushing and knocking are likely to cause the coating to peel off, thereby affecting the anode conductivity and catalytic activity, increasing the cell voltage, reducing the electrical efficiency, increasing energy consumption, and uneven distribution of power lines affecting the quality of electrolytic cobalt products.

[0003] During the electrowinning operation, an anode bag is generally used. The main anode reaction is the oxygen evolution reaction, which easily oxidizes cobalt, iron, etc. to high valence states. The high valence oxides continuously adsorb and peel off on the anode surface. The peeled anode mud enters the anode bag, and the fine anode mud is easily adhered to the anode bag, affecting the diffusion of the electrolyte solution. Therefore, the anode mud in the anode bag needs to be cleaned regularly. The collected anode mud is mainly high-valence cobalt oxides and peeled lead-coated layers, and the anode mud needs to be leached to recover cobalt.

[0004] The leaching of anode mud generally uses acid leaching, such as hydrochloric acid or sulfuric acid combined with sodium sulfite, sulfur dioxide, etc. for reduction leaching, or alkali leaching, such as liquid alkali combined with an oxidant (such as O2, H2O2) for pressure leaching, etc. After leaching, it is necessary to adjust the PH to precipitate impurities such as iron and aluminum, or perform extraction for impurity removal and back extraction to obtain a cobalt sulfate solution. This process has problems such as high consumption of acids and alkalis for leaching and PH adjustment, low leaching rate, and long process. Mixing the anode mud into the nickel-cobalt hydroxide raw material, after leaching (first-stage acid leaching, second-stage reduction leaching), extraction (P204 impurity extraction, P507 cobalt extraction), and then degreasing and acid adjustment, it is used as an electrolyte solution to produce electrowinning cobalt. There are also problems such as a long process and high leaching cost. Summary of the Invention

[0005] To solve the above technical problems, the present invention provides a method for treating anode mud and anode liquid in electrowinning cobalt, including the following steps: S1. Obtain anode mud and anode liquid, the anode mud includes Co 3+ , and the anode liquid includes H + and Co 2+ ; S2. Add the anode liquid to the anode mud to obtain a reduction slurry, add hydrogen peroxide to the reduction slurry, perform reduction leaching to obtain a reduced solution; S3. Adjust the pH of the reduced solution to 1.5 - 2.5 with the anode liquid to obtain a regenerated electrolyte solution.

[0006] Among them, the step S2 further includes: adding the hydrogen peroxide to the reduction slurry until the pH of the reduction slurry is 1-1.5 to obtain a post-reduction liquid.

[0007] Among them, in the step S1: the concentration of hydrogen ions in the anolyte is 1.2-1.6 mol / L; Preferably, the concentration of hydrogen ions in the anolyte is any one or the range between any two of 1.2 mol / L, 1.3 mol / L, 1.4 mol / L, 1.5 mol / L, and 1.6 mol / L.

[0008] Among them, in the step S2: the molar ratio of the hydrogen peroxide to the content of cobalt element in the anode mud is (1.2-1.8):2; Preferably, the molar ratio of the hydrogen peroxide to the content of cobalt element in the anode mud is any one or the range between any two of 1.2:2, 1.4:2, 1.6:2, and 1.8:2; Among them, in the step S2: the liquid-solid ratio of the anolyte to the anode mud is (4-10):1, and the time for reduction leaching is 4-6 h.

[0009] Preferably, the liquid-solid ratio of the anolyte to the anode mud is any one or the range between any two of 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, and 10:1, and the time for reduction leaching is any one or the range between any two of 4 h, 5 h, and 6 h.

[0010] Among them, in the step S1, the anolyte includes sulfuric acid, and the anode mud includes lead ions; after the step S2, it further includes: S21. Adjust the pH of the post-reduction liquid to 3-4, add barium carbonate to the post-reduction liquid and stir. A purification precipitate and a purified liquid are obtained through reaction. After aging, solid-liquid separation is performed. The liquid-solid ratio of the barium carbonate to the post-reduction liquid is (0.5-1):1 g / L. The purification precipitate includes barium sulfate and lead sulfate, and the rotation speed of the stirring is 100-200 r / min.

[0011] Preferably, the liquid-solid ratio of the barium carbonate to the post-reduction liquid is any one or the range between any two of 0.5 g / L, 0.6 g / L, 0.7 g / L, 0.8 g / L, 0.9 g / L, 1.0 g / L, and 1.1 g / L.

[0012] Among them, after the step S21, the following steps are further included: S22, using an activated carbon column to remove oil from the liquid after impurity removal. The height-diameter ratio of the activated carbon column is 2:(1-3), the treatment flow rate is 2-3 BV (bed volume, referring to the volume of liquid passing through a certain cross-section per unit time), the activated carbon column includes granular activated carbon with a mesh size of 4-8 and granular activated carbon with a mesh size of 20-80, and the mass ratio of the granular activated carbon with a mesh size of 4-8 to the granular activated carbon with a mesh size of 20-80 is 1:(2-3).

[0013] Among them, in the step S21: the reaction time between the barium carbonate and the reduced liquid is (0.5-1) h, and the aging time is 2-4 h.

[0014] Among them, in the step S21, the impurity removal precipitate further includes iron elements and aluminum elements.

[0015] It can be understood that the iron elements and aluminum elements in the reduced liquid will precipitate during the process of adjusting the pH to 3-4.

[0016] Among them, in the step S3: the regenerated electrowinning solution can be used for the preparation of electrowon cobalt.

[0017] The present invention realizes short-process and high-efficiency leaching by using electrowinning anode liquid and hydrogen peroxide to leach anode slime. When leaching with electrowinning anode liquid, the leaching solution after lead and oil removal can be recycled as electrowinning circulating liquid to produce qualified electrowon cobalt, which not only utilizes the acidity of the anode liquid but also avoids the subsequent treatment of the leaching solution. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on the structures shown in these drawings.

[0019] Figure 1 It is the process flow diagram of Embodiment 1 of the present invention.

[0020] The realization of the object of the present invention, functional features and advantages will be further described in conjunction with the embodiments with reference to the drawings. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0021] The following will clearly and completely describe the technical solutions in the embodiments. Obviously, the described embodiments are only some of the embodiments of the present invention, rather than all of them. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

[0022] A method for treating electrowinning cobalt anode slime and anode liquid comprises the following steps: S1. Obtain anode slime and anode liquid, wherein the anode slime contains Co 3+ , and the anode liquid contains H + and Co 2+ ; In the embodiments of the present application, titanium-plated lead is used as the anode. During the preparation of electrowinning cobalt, the anode slime of electrowinning cobalt mainly consists of high-valent cobalt oxide, cobalt hydroxide, and lead detached from the anode, while the anode liquid mainly consists of sulfuric acid and cobalt sulfate solution.

[0023] S2. Add the anode liquid to the anode slime to obtain a reduction slurry, and add hydrogen peroxide to the reduction slurry for reduction leaching to obtain a post-reduction liquid; Utilize the acid in the anode liquid and the ability of hydrogen peroxide to reduce high-valent cobalt ions under acidic conditions to leach divalent cobalt ions, enabling them to be further utilized.

[0024] S3. Adjust the pH of the post-reduction liquid to 1.5 - 2.5 with the anode liquid to obtain a regenerated electrowinning solution.

[0025] The regenerated electrowinning solution obtained by adjusting the acid of the post-reduction liquid can be used as the electrowinning solution during the electrowinning of cobalt.

[0026] Please refer to Figure 1 , Figure 1 which is the process flow chart of Embodiment 1 of the present invention. In this embodiment, the anode slime and anode liquid in the electrowinning cell are obtained, the anode liquid and anode slime are added to an acid leaching tank to obtain a reduction slurry, then hydrogen peroxide is added to the acid leaching tank for reduction leaching to obtain a post-reduction liquid. The post-reduction liquid is transferred to a lead removal tank, and barium carbonate is added to obtain a lead removal precipitate and a post-lead removal liquid. The post-lead removal liquid is transferred to a filter press for solid-liquid separation. The post-lead removal liquid after oil removal is added to an acid adjustment tank, and the acid is adjusted with the anode liquid to obtain a regenerated electrowinning solution. The regenerated electrowinning solution can be added to the electrowinning cell for the preparation of electrowinning cobalt.

[0027] Embodiment 1 The anode slime and anode solution are obtained. The anode solution is added to the anode slime according to a liquid-solid ratio of 4:1 to obtain a reduction slurry. The hydrogen ion concentration in the reduction slurry is 1.4 mol / L, and the cobalt element concentration is 65 g / L. Hydrogen peroxide is added according to a molar ratio of 1.2:2 to the cobalt element until the pH of the system is 1.5. Reduction leaching is carried out to obtain a reduced solution. The reduction leaching time is 5 h, and the pH of the reduced solution is 3. The anode solution is used to adjust the acidity of the reduced solution, and the pH of the reduced solution is adjusted to 1.5 to obtain a regenerated electrolyte solution with a cobalt concentration of 96 g / L. The regenerated electrolyte solution can be used for the preparation of electrowon cobalt.

[0028] Example 2 The anode slime and anode solution are obtained. The anode solution is added to the anode slime according to a liquid-solid ratio of 4:1 to obtain a reduction slurry. The hydrogen ion concentration in the reduction slurry is 1.4 mol / L, and the cobalt element concentration is 65 g / L. Hydrogen peroxide is added according to a molar ratio of 1.2:2 to the cobalt element until the pH of the system is 1.5. Reduction leaching is carried out to obtain a reduced solution. The reduction leaching time is 5 h, and the pH of the reduced solution is 3. Barium carbonate is added to the reduced solution and stirred to obtain a purified solution and a purification precipitate, and then aging is carried out. Barium carbonate is added at 0.5 g per liter of the reduced solution, the stirring speed is 100 r / min, the reaction time is 0.5 h, and the aging time is 2 h. The lead element content in the purified solution is detected to be 0.4 ppm. The purified solution is subjected to pressure filtration to separate the purified solution and the purification precipitate. The anode solution is used to adjust the acidity of the purified solution, and the pH of the purified solution is adjusted to 1.5 to obtain a regenerated electrolyte solution with a cobalt concentration of 95 g / L. The regenerated electrolyte solution can be used for the preparation of electrowon cobalt meeting the YS / T255-2009, Co9995 standard.

[0029] Example 3 Obtain anode slime and anode liquor. Add the anode liquor to the anode slime according to a liquid-solid ratio of 4:1 to obtain a reduction slurry. The hydrogen ion concentration in the reduction slurry is 1.4 mol / L, and the cobalt element concentration is 65 g / L. Add hydrogen peroxide according to a molar ratio of 1.2:2 to the cobalt element until the pH of the system is 1.5, and perform reduction leaching to obtain a reduced post-leaching solution. The reduction leaching time is 5 h, and the pH of the reduced post-leaching solution is 3. Add barium carbonate to the reduced post-leaching solution and stir to obtain a post-impurity-removal solution and impurity-removal precipitate, and then perform aging. Add barium carbonate at 0.5 g per liter of the reduced post-leaching solution, with a stirring speed of 100 r / min, a reaction time of 0.5 h, and an aging time of 2 h. Detect that the lead element content in the post-impurity-removal solution is 0.4 ppm, and perform pressure filtration on the post-impurity-removal solution to separate the post-impurity-removal solution and the impurity-removal precipitate. Use an activated carbon column to remove oil from the post-impurity-removal solution. The height-diameter ratio of the activated carbon column is 2:1, the treatment flow rate is 2 BV (bed volume, referring to the liquid volume passing through a certain cross-section per unit time), and the mass ratio of 4-8 mesh granular activated carbon to 20-80 mesh granular activated carbon is 1:2. After oil removal, the oil content in the post-impurity-removal solution is 0.6 ppm. Use the anode liquor to adjust the acidity of the post-impurity-removal solution, adjust the pH of the post-impurity-removal solution to 1.5 to obtain a regenerated electrolyte solution, in which the cobalt concentration is 96 g / L. The regenerated electrolyte solution can be used for the preparation of electrowon cobalt meeting the Co9995 standard of YS / T 255-2009.

[0030] Example 4 Obtain anode slime and anode liquor. Add the anode liquor to the anode slime according to a liquid-solid ratio of 6:1 to obtain a reduction slurry. The hydrogen ion concentration in the reduction slurry is 1.6 mol / L, and the cobalt element concentration is 60 g / L. Add hydrogen peroxide according to a molar ratio of 1.6:2 to the cobalt element until the pH of the system is 1, and perform reduction leaching to obtain a reduced post-leaching solution. The reduction leaching time is 4 h, and the pH of the reduced post-leaching solution is 4. Add barium carbonate to the reduced post-leaching solution and stir to obtain a post-impurity-removal solution and impurity-removal precipitate, and then perform aging. Add barium carbonate at 0.8 g per liter of the reduced post-leaching solution, with a stirring speed of 150 r / min, a reaction time of 1 h, and an aging time of 3 h. Detect that the lead element content in the post-impurity-removal solution is 0.2 ppm, and perform pressure filtration on the post-impurity-removal solution to separate the post-impurity-removal solution and the impurity-removal precipitate. Use an activated carbon column to remove oil from the post-impurity-removal solution. The height-diameter ratio of the activated carbon column is 2:3, the treatment flow rate is 3 BV (bed volume, referring to the liquid volume passing through a certain cross-section per unit time), and the mass ratio of 4-8 mesh granular activated carbon to 20-80 mesh granular activated carbon is 1:3. After oil removal, the oil content in the post-impurity-removal solution is 0.5 ppm. Use the anode liquor to adjust the acidity of the post-impurity-removal solution, adjust the pH of the post-impurity-removal solution to 1.8 to obtain a regenerated electrolyte solution, in which the cobalt concentration is 92 g / L. The regenerated electrolyte solution can be used for the preparation of electrowon cobalt meeting the Co9995 standard of YS / T 255-2009.

[0031] Example 5 Obtain anode slime and anode liquor. Add the anode liquor to the anode slime according to a liquid-solid ratio of 10:1 to obtain a reduction slurry. The hydrogen ion concentration in the reduction slurry is 1.2 mol / L, and the cobalt element concentration is 70 g / L. Add hydrogen peroxide according to a molar ratio of 1.8:2 to the cobalt element until the pH of the system is 1.2, and perform reduction leaching to obtain a post-reduction solution. The reduction leaching time is 6 h, and the pH of the post-reduction solution is 3.5. Add barium carbonate to the post-reduction solution and stir to obtain a post-impurity-removal solution and impurity-removal precipitate, and then perform aging. Barium carbonate is added at 1.1 g per liter of the post-reduction solution, the stirring speed is 200 r / min, the reaction time is 0.8 h, and the aging time is 4 h. Detect that the lead element content in the post-impurity-removal solution is 0.1 ppm, and perform pressure filtration on the post-impurity-removal solution to separate the post-impurity-removal solution and the impurity-removal precipitate. Use an activated carbon column to remove oil from the post-impurity-removal solution. The height-diameter ratio of the activated carbon column is 1:1, the treatment flow rate is 2.5 BV (bed volume, referring to the liquid volume passing through a certain cross-section per unit time), and the mass ratio of 4-8 mesh granular activated carbon to 20-80 mesh granular activated carbon is 2:5. After oil removal, the oil content in the post-impurity-removal solution is 0.54 ppm. Use the anode liquor to adjust the acidity of the post-impurity-removal solution and adjust the pH of the post-impurity-removal solution to 2.5 to obtain a regenerated electrolyte solution, in which the cobalt concentration is 98 g / L. The regenerated electrolyte solution can be used for the preparation of electrowon cobalt meeting the YS / T 255-2009, Co9995 standard.

[0032] The above are only the preferred embodiments of the present invention, and do not limit the patent scope of the present invention accordingly. All equivalent structural transformations made under the inventive concept of the present invention by using the content of the specification of the present invention, or direct / indirect applications in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A method for treating electrowinning cobalt anode slime and anode liquid, characterized in that It includes the following steps: S1. Obtain anode slime and anode liquor, where the anode slime includes Co 3+ , and the anode liquor includes H + and Co 2+ ; S2. Add the anolyte to the anode mud to obtain a reduction slurry, add hydrogen peroxide to the reduction slurry, and perform reduction leaching to obtain a post-reduction solution; S3. Adjust the pH of the post-reduction solution to 1.5 - 2.5 with the anolyte to obtain a regenerated electrowinning solution.

2. The treatment method of electrowinning cobalt anode slime and anode liquid according to claim 1, characterized in that, The step S2 further includes: adding the hydrogen peroxide to the reduction slurry until the pH of the reduction slurry is 1 - 1.5 to obtain a post-reduction solution.

3. A method for treating electrowinning cobalt anode slime and anode liquid according to claim 1, characterized in that, In the step S1: the concentration of hydrogen ions in the anolyte is 1.2 - 1.6 mol / L.

4. The treatment method of electrowinning cobalt anode slime and anode liquid according to claim 3, characterized in that, In the step S2: the concentration of cobalt element in the reduction slurry is 60 - 70 g / L, and the molar ratio of the hydrogen peroxide to the content of cobalt element in the anode mud is (1.2 - 1.8):

2.

5. A method for treating electrowinning cobalt anode slime and anode solution according to claim 3, characterized in that, In the step S2: the liquid-solid ratio of the anolyte to the anode mud is (4 - 10):1, and the time of the reduction leaching is 4 - 6 h.

6. A method for treating electrowinning cobalt anode slime and anode liquid according to claim 2, characterized in that, In the step S1, the anolyte includes sulfuric acid, and the anode mud includes lead ions; after the step S2, it further includes: S21. Adjust the pH of the post-reduction solution to 3 - 4, add barium carbonate to the post-reduction solution and stir. React to obtain an impurity removal precipitate and an impurity removal post-solution. After aging, perform solid-liquid separation. The liquid-solid ratio of the barium carbonate to the post-reduction solution is (0.5 - 1):1 g / L. The impurity removal precipitate includes barium sulfate and lead sulfate, and the rotation speed of the stirring is 100 - 200 r / min.

7. The treatment method of electrowinning cobalt anode slime and anode liquid according to claim 6, characterized in that, After the step S21, it further includes: S22. Use an activated carbon column to remove oil from the impurity removal post-solution. The height-diameter ratio of the activated carbon column is 2:(1 - 3), the treatment flow rate is 2 - 3 BV. The activated carbon column includes granular activated carbon with a mesh size of 4 - 8 and granular activated carbon with a mesh size of 20 - 80. The mass ratio of the granular activated carbon with a mesh size of 4 - 8 to the granular activated carbon with a mesh size of 20 - 80 is 1:(2 - 3).

8. A method for treating electrowinning cobalt anode slime and anode solution according to claim 6, characterized in that, In the step S21: the reaction time of the barium carbonate and the post-reduction solution is (0.5 - 1) h, and the aging time is 2 - 4 h.

9. The treatment method of electrowinning cobalt anode slime and anode liquid according to claim 6, characterized in that, In the step S21, the impurity removal precipitate further includes iron element and aluminum element.

10. A method for treating electrowinning cobalt anode slime and anode liquid according to claim 1, characterized in that, In the step S3: the concentration of cobalt element in the regenerated electrowinning solution is greater than or equal to 90 g / L and can be used for the preparation of electrowon cobalt.

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