Method for removing cadmium from copper-cobalt ore at depth

Abstract

The application discloses a method for deeply removing cadmium from copper-cobalt ore, and the method comprises the following steps: adding copper-containing liquid of a copper refining process into a pre-cobalt precipitation liquid in a copper-cobalt ore treatment process to obtain a mixed liquid; adding metal powder into the mixed liquid to replace and remove cadmium, and obtaining a post-cadmium removal liquid after solid-liquid separation; and separating cobalt from the post-cadmium removal liquid and the replaced metal to obtain a purified cobalt product. The application not only utilizes the copper-containing liquid generated in other processes in the copper-cobalt ore treatment process, effectively promotes the replacement and removal of cadmium by the metal powder in the pre-cobalt precipitation liquid under the conditions of no purchase of reagents and no heating, reduces the amount of the replaced metal, reduces the energy consumption of the cadmium removal, saves the cost of the cadmium removal, and improves the purity of the cobalt product; and the application also formulates different subsequent separation processes of cobalt and the replaced metal for different metal powder replacement and cadmium removal processes, effectively expands the application metal range of the metal powder replacement and cadmium removal process in the prior art, and provides more choices for the implementation of the deep cadmium removal process of the copper-cobalt ore.

Description

Technical Field

[0001] This invention relates to the field of heavy metal recycling technology, and in particular to a method for deep cadmium removal from copper-cobalt ore. Background Technology

[0002] The processing of copper-cobalt ore generally involves separating the copper first, recovering it through electrowinning, then separating the remaining cobalt and other impurities, and finally recovering the cobalt by precipitation of the purified solution. However, since the solution before cobalt precipitation sometimes contains a certain amount of cadmium, and cadmium and cobalt precipitate at similar pH values, if cadmium is not thoroughly removed, it will affect the purity of the subsequent cobalt precipitation product.

[0003] Metal powder displacement is a commonly used industrial method for removing cadmium from liquid feed. It typically uses a metal with a more negative standard electrode potential than cadmium, such as zinc powder. However, because cadmium's standard electrode potential is already quite negative, not much different from zinc, its thermodynamic driving force is relatively small. Therefore, a larger amount of zinc powder is generally required, and the process must be carried out under medium-temperature conditions (around 50°C) to ensure that the final cadmium concentration after displacement removal meets the requirements.

[0004] In view of this, a method that can effectively reduce the amount of replacement metal used and achieve deep cadmium removal without heating is of great significance for reducing the cost of cadmium removal in copper-cobalt ore processing and improving the purity of precipitated cobalt products. Summary of the Invention

[0005] The purpose of this invention is to fully utilize the characteristics of copper-cobalt ore and the copper-containing liquid generated in other processes during copper-cobalt ore processing. Without purchasing reagents or heating, it effectively promotes the depth of the cadmium removal reaction by metal powder replacement, achieving the process effect of deep cadmium removal from copper-cobalt ore pre-cobalt precipitation liquid without heating. At the same time, by developing different subsequent separation processes for cobalt and replacement metals for different metal powder replacement cadmium removal processes, it also effectively expands the range of metals applicable to metal powder replacement cadmium removal.

[0006] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0007] A method for deep cadmium removal from copper-cobalt ore, the method comprising:

[0008] A copper-containing liquid is added to the pre-cobalt precipitation solution during the copper-cobalt ore processing to obtain a mixed solution;

[0009] Metal powder was added to the mixture to displace and remove cadmium, and the solid-liquid mixture was separated to obtain the cadmium-removed liquid.

[0010] The cadmium-removed liquid is subjected to separation of cobalt and the replacement metal to obtain a purified cobalt product.

[0011] As a further improvement of the present invention, the copper-containing liquid is the anolyte from the copper electrowinning process in the copper-cobalt ore refining process.

[0012] As a further improvement of the present invention, the molar ratio of copper to cadmium in the mixture is controlled to be (4-8):1.

[0013] As a further improvement of the present invention, the metal powder is one or more of lithium powder, potassium powder, sodium powder and magnesium powder.

[0014] As a further improvement of the present invention, the metal powder is zinc powder.

[0015] As a further improvement of the present invention, the metal powder is aluminum powder.

[0016] As a further improvement of the present invention, the cobalt and the replacement metal are separated in the cadmium removal solution to obtain a purified cobalt product comprising:

[0017] A first precipitant is added to the cadmium-removed liquid to precipitate cobalt, thereby obtaining a cobalt product.

[0018] As a further improvement of the present invention, the cobalt and the replacement metal are separated in the cadmium removal solution to obtain a purified cobalt product comprising:

[0019] An extractant was added to the cadmium-removed liquid to extract and remove the replaced metal, resulting in a purified cobalt-precipitated pre-liquid.

[0020] Add a first precipitant to the purified cobalt precipitation solution to precipitate cobalt and obtain the cobalt product.

[0021] As a further improvement of the present invention, the cobalt and the replacement metal are separated in the cadmium removal solution to obtain a purified cobalt product comprising:

[0022] A second precipitant is added to the cadmium-removed solution to remove the replaced metal, resulting in a purified cobalt-precipitated solution.

[0023] Add a first precipitant to the purified cobalt precipitation solution to precipitate cobalt and obtain the cobalt product.

[0024] As a further improvement of the present invention, the first precipitant is one or both of sodium hydroxide and potassium hydroxide.

[0025] As a further improvement of the present invention, the extractant is one or both of diisooctyl phosphate and ethylhexyl phosphate mono-2-ethylhexyl ester.

[0026] As a further improvement of the present invention, the second precipitant is one or more of sodium hydroxide, potassium hydroxide, and lime milk.

[0027] The beneficial effects of this invention are:

[0028] The present invention provides a method for deep cadmium removal from copper-cobalt ore. This method involves adding a copper-containing liquid to the pre-cobalt precipitation solution during the copper-cobalt ore processing to obtain a mixed solution; then adding metal powder to the mixed solution for cadmium removal via displacement; after solid-liquid separation, a post-cadmium-removed solution is obtained; finally, the post-cadmium-removed solution is separated from the displacement metal to obtain a purified cobalt product. Through this method, the present invention proposes a method that effectively promotes the depth of the cadmium removal reaction via metal powder displacement, thereby reducing the amount of displacement metal used in the process and achieving deep removal of cadmium impurities from the pre-cobalt precipitation solution without heating. This method not only effectively reduces the cost of cadmium removal in the copper-cobalt ore processing and expands the range of metals that can be applied in cadmium removal via metal powder displacement, but also significantly improves the purity of the precipitated cobalt product, thus having broad application prospects.

[0029] Other features and advantages of the invention will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures pointed out in the description and the drawings. Attached Figure Description

[0030] Figure 1 This is a schematic flowchart of the method for deep cadmium removal from copper-cobalt ore according to the present invention. Detailed Implementation

[0031] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] To meet the potential cadmium removal requirements in the pre-cobalt precipitation solution during copper-cobalt ore processing, and to address the issues of large zinc powder usage and high reaction temperatures required in existing cadmium removal technologies, this invention proposes an improved enhanced method for cadmium removal via metal powder replacement. This method effectively promotes cadmium replacement in the pre-cobalt precipitation solution, expands the range of applicable metals for existing metal powder replacement cadmium removal, reduces cadmium removal costs, and achieves a final cadmium concentration reduction to meet design requirements at room temperature.

[0033] Specifically, the method for deep cadmium removal from copper-cobalt ore provided by this invention can be found in [reference needed]. Figure 1 As shown, the main steps include:

[0034] (1) A certain amount of copper-containing solution from the copper refining process is added to the pre-cobalt precipitation solution during the copper-cobalt ore processing to form a mixed solution. The molar ratio of copper to cadmium in the mixed solution is controlled within the range of (4-8):1. Preferably, the copper-containing solution can be the anolyte from the copper refining process during the copper-cobalt ore processing. This avoids the need to purchase reagents from external sources, saving costs.

[0035] (2) Add metal powder to the aforementioned mixture to displace and remove cadmium. After solid-liquid separation, obtain the cadmium-removed liquid. The metal powder can be divided into three categories: Category 1 includes lithium (-3.04V), potassium (-2.931V), sodium (-2.713V), and magnesium (-2.37V); Category 2 includes zinc (-0.7618V); and Category 3 includes aluminum (-1.662V).

[0036] (3) The cobalt and the replacement metal were separated from the cadmium-removed liquid to obtain the purified cobalt product.

[0037] When the replacement metal is of type 1, since the replacement metal does not enter the cobalt product, cobalt can be directly precipitated by adding a precipitant. Suitable precipitants include sodium hydroxide and potassium hydroxide.

[0038] When the substituted metal is of type 2, the cadmium-removed solution must first be extracted to remove the substituted metal, yielding a pre-purified cobalt precipitation solution. Phosphoric acid extractants such as P204 (diisooctyl phosphate) and P507 (ethylhexyl phosphate mono-2-ethylhexyl ester) can be used. Then, a precipitant is added to the purified cobalt precipitation solution to precipitate cobalt, obtaining the final cobalt product. The precipitant is again sodium hydroxide, potassium hydroxide, etc.

[0039] When the replacement metal is of type 3, the replacement metal needs to be removed by precipitation of the cadmium removal solution first, resulting in a purified cobalt precipitation pre-solution. Sodium hydroxide, potassium hydroxide, lime milk, etc., can be used as precipitants. Then, a precipitant is added to the purified cobalt precipitation pre-solution to precipitate cobalt, yielding the final cobalt product. The precipitant is again sodium hydroxide, potassium hydroxide, etc.

[0040] Therefore, this invention not only utilizes the copper-containing liquid generated during other processes in the copper-cobalt ore treatment, effectively promoting the depth of the cadmium removal reaction by metal powder replacement in the pre-cobalt precipitation solution without purchasing reagents or heating, reducing the amount of replacement metal used, lowering cadmium removal energy consumption, thereby saving cadmium removal costs and improving the purity of cobalt products; but also effectively expands the range of applicable metals in the existing metal powder replacement cadmium removal process by developing different subsequent separation processes for cobalt and replacement metals for different metal powder replacement cadmium removal processes, providing more options for the implementation of deep cadmium removal processes in copper-cobalt ore.

[0041] The following will describe in detail the implementation process and effects of the method for deep cadmium removal from copper-cobalt mines provided by the present invention, using three specific embodiments.

[0042] Example 1:

[0043] 1. A certain amount of anolyte from the copper electrowinning process is added to the pre-cobalt precipitation solution during the copper-cobalt ore processing to obtain a mixed solution. The molar ratio of copper to cadmium in the mixed solution is controlled at 4.95:1, as shown in Table 1 below:

[0044] Table 1. Main element content of the mixed solution (mg / L)

[0045] Co Cd Mg Zn Al Cu 3006 21 1500 980 1.6 104

[0046] 2. Add metallic magnesium to the mixture to displace and remove cadmium. After solid-liquid separation, the cadmium-removed solution is obtained. The main components of the cadmium-removed solution are shown in Table 2 below:

[0047] Table 2. Main element content of the solution after cadmium removal (mg / L)

[0048] Co Cd Mg Zn Al Cu 2869 0.8 1735 1.8 0.9 1.2

[0049] 3. Add sodium hydroxide solution to the cadmium-removed liquid to precipitate cobalt, thereby separating it from magnesium and obtaining purified cobalt hydroxide product, in which the cadmium content is <0.05% and the magnesium content is <1%.

[0050] Example 2:

[0051] 1. A certain amount of anolyte from the copper electrowinning process is added to the cobalt precipitation pretreatment solution in the copper-cobalt ore processing to obtain a mixed solution. The molar ratio of copper to cadmium in the mixed solution is controlled at 7.14:1. The main components of the mixed solution are shown in Table 3 below:

[0052] Table 3. Main element content of the mixed solution (mg / L)

[0053] Co Cd Mg Zn Al Cu 3006 21 1500 980 1.6 150

[0054] 2. Add metallic zinc to the mixture to displace and remove cadmium. After solid-liquid separation, the cadmium-removed solution is obtained. The main components of the obtained cadmium-removed solution are shown in Table 4 below:

[0055] Table 4. Main element content of the solution after cadmium removal (mg / L)

[0056]

[0057]

[0058] 3. The zinc-free solution after cadmium removal is extracted with P204 to separate it from cobalt. The zinc-free solution is then precipitated with sodium hydroxide solution to obtain a purified cobalt hydroxide product with cadmium content <0.05%, zinc content <1%, and magnesium content <1%.

[0059] Example 3:

[0060] 1. A certain amount of anolyte from the copper electrowinning process is added to the pre-cobalt precipitation solution during the copper-cobalt ore processing to obtain a mixed solution. The molar ratio of copper to cadmium in the mixed solution is controlled at 5.95:1. The main components of the resulting mixed solution are shown in Table 5 below:

[0061] Table 5. Main element content of the mixed solution (mg / L)

[0062] Co Cd Mg Zn Al Cu 3006 21 1500 980 1.6 125

[0063] 2. Add metallic aluminum to the mixture to displace and remove cadmium. After solid-liquid separation, the cadmium-removed liquid is obtained. The main components of the obtained cadmium-removed liquid are shown in Table 6 below:

[0064] Table 6. Main element content of the solution after cadmium removal (mg / L)

[0065] Co Cd Mg Zn Al Cu 2913 0.3 1500 83 18 2.1

[0066] 3. Add sodium hydroxide solution to the cadmium-removed liquid to control the pH to 3-4 to precipitate and remove aluminum. After separation from cobalt, add sodium hydroxide solution to the obtained aluminum-removed liquid to precipitate cobalt, and obtain a purified cobalt hydroxide product with cadmium content <0.05%, aluminum content <1%, zinc content <1%, and magnesium content <1%.

[0067] In summary, the method for deep cadmium removal from copper-cobalt ore provided by this invention involves adding copper-containing liquid from the copper refining process to the pre-cobalt precipitation solution during the copper-cobalt ore processing to obtain a mixed solution; then, metal powder is added to the mixed solution for cadmium removal by displacement, followed by solid-liquid separation to obtain a post-cadmium-removed solution; finally, cobalt and the displacement metal are separated in the post-cadmium-removed solution to obtain a purified cobalt product. Through this method, this invention not only utilizes the copper-containing liquid generated in other processes during copper-cobalt ore processing, effectively promoting the depth of the cadmium removal reaction by metal powder displacement in the pre-cobalt precipitation solution without purchasing reagents or heating, reducing the amount of displacement metal used, lowering energy consumption for cadmium removal, and achieving the goals of saving cadmium removal costs and improving the purity of cobalt products; but also effectively expands the range of applicable metals in the existing metal powder displacement cadmium removal process by developing different subsequent separation processes for cobalt and the displacement metal for different metal powder displacement cadmium removal processes, providing more options for the implementation of deep cadmium removal processes in copper-cobalt ore. Therefore, it has broad application prospects.

[0068] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for deep cadmium removal from copper-cobalt ore, characterized in that, The method includes: A copper-containing liquid is added to the pre-cobalt precipitation solution during the copper-cobalt ore processing to obtain a mixed solution; the molar ratio of copper to cadmium in the mixed solution is controlled to be (4~8):1; wherein, the copper-containing liquid is the anolyte of the copper electrowinning process during the copper purification process of copper-cobalt ore; Metal powder is added to the mixture to displace and remove cadmium, and the solid-liquid mixture is separated to obtain a cadmium-removed liquid; wherein the metal powder is one or more of lithium powder, potassium powder, sodium powder and magnesium powder; or, the metal powder is aluminum powder; or, the metal powder is zinc powder. The cadmium-removed solution is subjected to separation of cobalt and the replaced metal to obtain a purified cobalt product, comprising: When the metal powder is one or more of lithium powder, potassium powder, sodium powder and magnesium powder, a first precipitant is added to the cadmium-removed liquid to precipitate cobalt and obtain a cobalt product. When the metal powder is zinc powder, an extractant is added to the cadmium-removed liquid to extract and remove the replaced metal, resulting in a purified cobalt precipitation pre-liquid; a first precipitant is added to the purified cobalt precipitation pre-liquid to precipitate cobalt, resulting in a cobalt product. When the metal powder is aluminum powder, a second precipitant is added to the cadmium-removed liquid to remove the replaced metal, resulting in a purified cobalt-precipitated pre-liquid; a first precipitant is added to the purified cobalt-precipitated pre-liquid to precipitate cobalt, resulting in a cobalt product.

2. The method for deep cadmium removal from copper-cobalt ore according to claim 1, characterized in that, The first precipitant is one or both of sodium hydroxide and potassium hydroxide.

3. The method for deep cadmium removal from copper-cobalt ore according to claim 1, characterized in that, The extractant is one or both of diisooctyl phosphate and ethylhexyl phosphate mono-2-ethylhexyl ester.

4. The method for deep cadmium removal from copper-cobalt ore according to claim 1, characterized in that, The second precipitant is one or more of sodium hydroxide, potassium hydroxide, and lime milk.

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