Method for treating cobalt carbonate mother liquor
By combining cobalt removal resin and low-concentration ammonium sulfide, the problem of removing complexed cobalt from cobalt carbonate mother liquor was solved, achieving efficient cobalt recovery and improved ammonium chloride purity.
Patent Information
- Application Number
- CN202511476843.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-10-16
- Publication Date
- 2026-01-20
AI Technical Summary
In existing technologies, the cobalt carbonate mother liquor contains complexed cobalt, which prevents the cobalt removal resin from adsorbing it. The byproduct ammonium chloride has a reddish color, affecting the quality and causing the loss of the rare metal cobalt.
The process involves first removing free cobalt ions with a cobalt-removing resin, then breaking down the complex with a low-concentration ammonium sulfide, and then further removing cobalt with a similar resin. The pH is then adjusted to acidity with hydrochloric acid, forming a complete process flow.
It effectively removes cobalt from cobalt carbonate mother liquor, improves the purity of the by-product ammonium chloride, achieves a cobalt recovery rate of 99.99%, and reduces the cobalt content in ammonium chloride to below 0.0007 wt%.
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Figure CN121361811A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of precursor mother liquor treatment, and particularly relates to a method for treating a cobalt carbonate mother liquor. BACKGROUND
[0002] In the production process of a cobalt carbonate battery precursor, raw materials cobalt chloride and ammonium bicarbonate are used, and cobalt carbonate slurry is obtained through precipitation. A large amount of mother liquor is generated during the solid-liquid separation of the cobalt carbonate slurry, and a small amount of cobalt exists in the mother liquor. The current treatment process is to adsorb and separate the cobalt in the mother liquor through a cobalt removal resin, then evaporate and crystallize the mother liquor through MVR, and finally obtain a byproduct ammonium chloride crystal. Since a small amount of cobalt ammine complex exists in the cobalt carbonate mother liquor, the cobalt removal resin cannot be adsorbed, and therefore the byproduct ammonium chloride evaporated contains a small amount of cobalt, which causes the overall color of the ammonium chloride to be reddish, affecting the quality of the ammonium chloride and causing the loss of the rare metal cobalt. Therefore, it is necessary to remove the complexed cobalt in the cobalt carbonate mother liquor. SUMMARY
[0003] The technical problem to be solved by the present application is to effectively remove the complexed cobalt in the cobalt carbonate mother liquor.
[0004] The method for treating a cobalt carbonate mother liquor adopts the following scheme: first, remove the free cobalt ions by using a cobalt removal resin, then break the complex of the cobalt carbonate mother liquor after cobalt removal by using low-concentration ammonium sulfide, and then remove the free cobalt ions again by using a cobalt removal resin, and the specific steps are as follows: a. Add the cobalt carbonate mother liquor to hydrochloric acid to adjust the pH to be acidic for decarburization; b. Pass the decarburized cobalt carbonate mother liquor in step a through a cobalt removal resin for cobalt removal; c. Add the cobalt-removed cobalt carbonate mother liquor in step b to ammonium sulfide for complex breaking; d. Continue to pass the complex-broken cobalt carbonate mother liquor in step c through a cobalt removal resin for cobalt removal; In the method step a, the cobalt carbonate mother liquor is obtained by reacting cobalt chloride and ammonium bicarbonate, and then filtering the cobalt carbonate slurry through a precision filter.
[0005] Further, the cobalt content in the cobalt carbonate mother liquor is 0.02-0.2 g / L, and the ammonium chloride concentration is 50-150 g / L.
[0006] In the method step a, the concentration of the hydrochloric acid is 31 wt%.
[0007] In the method step a, the pH is 3-5.
[0008] Further, the pH is adjusted to between 3 and 5 to completely remove the carbonate in the ammonium chloride mother liquor to ensure the purity of the by-product ammonium chloride crystals.
[0009] In the above method step b, the three cobalt-removing resins are divided into A, B and C.
[0010] Further, the resin columns A, B and C are kept in standby.
[0011] Further, the cobalt ion concentration in the mother liquor after passing through the first group of resins in step a is reduced to 0.005-0.05 g / L.
[0012] In the above method step c, the ammonium sulfide concentration is 0.05-0.1 wt%.
[0013] Further, the purpose of adding ammonium sulfide is to break the cobalt complex in the cobalt-ammonia complex by the reaction between the sulfur ions and the cobalt ions to form free cobalt.
[0014] In the above step d, the mother liquor is obtained after pressure filtration in step c.
[0015] In the above step d, the cobalt-removing resin is the same type of resin as that in step b, and is the second group of resin column D.
[0016] Further, the cobalt ion concentration in the mother liquor after entering the D group of resin columns in the above step c is 0.0005-0.002 g / L.
[0017] The present application has the beneficial effects of fully recycling the cobalt in the cobalt carbonate mother liquor by using cobalt-removing resins and low-concentration ammonium sulfide, and improving the quality of the by-product ammonium chloride. The present application fully absorbs the free cobalt ions by using cobalt-removing resins, then breaks the complex of the cobalt by using low-concentration ammonium sulfide, and then absorbs the remaining cobalt in the mother liquor by using the cobalt-removing resins again after the breaking, so that the cobalt in the mother liquor can be reduced to below 0.002 g / L. BRIEF DESCRIPTION OF DRAWINGS
[0018] The specific embodiments of the present application will be further described in detail below with reference to the accompanying drawings, in which: Figure 1 The process flow chart of the present application is shown in the figure. DETAILED DESCRIPTION
[0019] The present application provides a method for treating a cobalt carbonate mother liquor, and the flow chart is shown in Figure 1 , The first group of resin columns comprises three resin columns A, B and C, and the second group of resin columns comprises one resin column D, and the four resin columns are the same resin. In the running process, any two of the resin columns A, B and C are connected in series, and the remaining one is used as a backup. When any one of the resin columns reaches adsorption saturation, the backup resin column is switched to ensure the continuous and stable operation of the whole process. When the second group of resin columns D reaches saturation, the system feeding is paused, and the resin column D is regenerated. After the regeneration is completed, the system continues to operate.
[0020] The cobalt carbonate mother liquor is treated according to the following steps in this example: (a) 31% hydrochloric acid is added to the cobalt carbonate acid adjusting tank to adjust the pH to 3.62; (b) the mother liquor after acid adjustment in step a is pumped into the first group of resin columns connected in series, and the liquid after passing through the resin enters buffer tank 1; (c) 0.05-0.1 wt% of ammonium sulfide solution is pumped into buffer tank 1, followed by a pressure filter; (d) the mother liquor after pressure filtration is directly pumped into the second group of resin columns D, the liquid after passing through the resin enters buffer tank 2, and finally is directly pumped into the MVR system for evaporation and crystallization; The ammonium chloride produced in this example is detected, and the elements are shown in Table 1; Table 1: Element content of ammonium chloride crystals
[0021] In the previous mother liquor treatment process, the cobalt content in ammonium chloride is generally between 0.02-0.15 wt%, as shown in Table 1, after using the present application, the cobalt carried away by ammonium chloride is reduced by more than 97%, and the Co content of the above ammonium chloride is 0.0007 wt%.
[0022] The cobalt carbonate mother liquor produced in this example and the liquid after passing through the first and second groups of resin are detected respectively, and the element content is shown in Tables 2 and 3.
[0023] Table 2: Concentration of key components of cobalt carbonate mother liquor
[0024] Table 3: Concentration of key components of the liquid after passing through the first and second groups of resin
[0025] In the previous mother liquor treatment process, the cobalt content in the cobalt carbonate mother liquor is 0.02-0.2 g / L, and after adsorption by the cobalt removal resin, the cobalt concentration is usually between 0.002-0.05 g / L. After using the present application, the cobalt concentration can be controlled below 0.002 g / L, and the comprehensive recovery rate of cobalt can reach 99.99%.
[0026] The above description is only preferred embodiments of the present application, and it should be pointed out that for those skilled in the art, various changes, modifications, replacements and variations can be made to the embodiments without departing from the technical principles of the present application, and these changes, modifications, replacements and variations should also be considered as the protection scope of the present application.
Claims
1. A process for treating a cobalt carbonate liquor characterised in that: Comprising the following steps: a. Adding the cobalt carbonate mother liquor into hydrochloric acid to adjust the pH to acidity for decarburization; b. Passing the decarburized cobalt carbonate mother liquor in step a through a cobalt removal resin for cobalt removal; c. Adding the cobalt removed cobalt carbonate mother liquor in step b into ammonium sulfide for complex breaking; d. Continuing to pass the complex broken cobalt carbonate mother liquor in step c through a cobalt removal resin for cobalt removal.
2. The method for treating a cobalt carbonate liquor according to claim 1, characterized in that: The cobalt carbonate mother liquor is the product filtered after the reaction of cobalt chloride and ammonium bicarbonate.
3. The method for treating a cobalt carbonate liquor of claim 1, wherein: The cobalt content in the cobalt carbonate mother liquor is 0.02-0.2 g / L, and the ammonium chloride concentration is 50-150 g / L.
4. The method for treating a cobalt carbonate liquor of claim 1, wherein: The concentration of the hydrochloric acid is 31wt%.
5. The method for treating a cobalt carbonate liquor of claim 1, wherein: In step a, the adjusted pH is 3-5.