Method for recycling nickel resources in copper electrolytic refining post-liquid
By adding a mixed solution of sodium thiosulfate and sodium diethyldithiocarbamate, a composite precipitant, to the copper electrolytic refining solution, adjusting the pH value, and heating, the three-phase separation of nickel, iron, and copper is achieved. This solves the problems of low nickel resource recovery efficiency and insufficient purity in existing technologies, and achieves a highly efficient and economical nickel resource recovery effect.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- YUNNAN COPPER CO LTD
- Filing Date
- 2026-04-02
- Publication Date
- 2026-06-26
AI Technical Summary
Existing technologies are insufficient for the efficient and selective separation of nickel resources from copper electrolytic refining solutions, resulting in low recovery efficiency and insufficient purity. Furthermore, conventional methods suffer from environmental pollution and high costs.
A mixed solution of sodium thiosulfate and sodium diethyldithiocarbamate, a composite precipitant, is used to adjust the pH value and heat the electrolyzed solution to form nickel, iron, and copper into substances with different properties. The three phases are separated through a one-step reaction, and nickel, iron, and copper are recovered separately.
It achieves efficient and high-quality recovery of nickel resources, with a nickel recovery rate of over 95% and a purity of over 85%, while simplifying the operation process and reducing environmental pollution and costs.
Smart Images
Figure CN122279219A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of valuable metal resource recycling technology, and relates to a method for recycling nickel resources in copper electrolytic refining liquid. Background Technology
[0002] In copper smelting, the electrolyte produced after the electrolytic refining of crude copper contains various valuable metals such as nickel, copper, and iron. Nickel, as an important non-ferrous metal, has significant economic value in its recovery and is also crucial for environmental protection and resource recycling. However, in hydrometallurgical processes, the coexistence of nickel with impurity ions such as copper and iron in the electrolyte makes it difficult to achieve efficient and selective separation of nickel using conventional methods. This results in low nickel resource recovery efficiency or insufficient purity of the recovered products, leading to resource waste.
[0003] Currently, the recovery of nickel resources from electrolytes mainly includes pyrometallurgical recovery, ion exchange, and chemical precipitation. Pyrometallurgical recovery typically involves high-temperature smelting or roasting to convert nickel-containing materials into nickel alloys or nickel matte, followed by further refining. This high-temperature process often results in large amounts of waste gas emissions, causing severe environmental pollution and high overall costs. Ion exchange utilizes resins for selective adsorption of nickel ions to achieve enrichment and separation; however, resins are expensive, have limited adsorption capacity, and require frequent regeneration, leading to high reagent consumption and wastewater generation. Chemical precipitation has certain advantages due to its simple operation and relatively low processing costs. However, as a widely used method, chemical precipitation often produces precipitates that are mixtures of various valuable metals. Subsequent complex separation processes are required to achieve high-purity recovery of a single valuable metal, or multiple separate precipitation processes, recovering one valuable metal at a time before proceeding to the next, increasing reagent consumption, extending the recovery cycle, and resulting in low recovery efficiency.
[0004] Therefore, it is necessary to provide a method for recovering nickel resources from copper electrolytic refining liquid, simplifying the operation and achieving efficient, high-recovery rate, and high-quality recovery of nickel resources. Summary of the Invention
[0005] To overcome the problems in the prior art, this invention adds a composite precipitant to the post-electrolysis solution. The composite precipitant reacts with nickel, iron, and copper to generate substances with significantly different properties, thereby directly separating the valuable metals in the post-electrolysis solution in one step. This eliminates the need for subsequent complex extraction of valuable metals from the precipitate, achieving efficient, high-recovery, and high-quality recovery of nickel resources.
[0006] To achieve the above objectives, the present invention is implemented through the following technical solution: The method includes the following steps: (1) Filter the copper electrolytic refining solution and adjust the pH of the copper electrolytic refining solution to 4.0~6.0.
[0007] Further optimization is achieved with a pH of 5.0 to 5.5.
[0008] (2) Add a composite precipitant to the copper electrolytic refining solution with pH=4.0~6.0 in step (1), and heat the copper electrolytic refining solution at the same time. After the reaction is completed, let the copper electrolytic refining solution stand until the reaction product liquid forms three layers.
[0009] The composite precipitant is a mixed aqueous solution of sodium thiosulfate and sodium diethyldithiocarbamate (DDTC).
[0010] During the addition of the composite precipitant, the copper electrolytic refining solution can be stirred to promote the reaction.
[0011] (3) The three-layer substance formed by the reaction product liquid in step (2) is recycled by layering. The bottom layer is filtered to obtain a precipitate. After washing the precipitate, the nickel resource recovery is completed.
[0012] Preferably, in step (1), sodium hydroxide or dilute sulfuric acid is used to adjust the pH of the copper electrolytic refining solution.
[0013] Preferably, in step (2), the concentration of sodium diethyldithiocarbamate in the composite precipitant is 0.05~0.2mol / L, the concentration of sodium thiosulfate in the composite precipitant is 0.05~0.6mol / L, and the molar ratio of sodium thiosulfate to sodium diethyldithiocarbamate in the composite precipitant is sodium thiosulfate: sodium diethyldithiocarbamate = 1:1~3:1.
[0014] Further preferred, the concentration of sodium diethyldithiocarbamate is 0.1 mol / L, and the concentration of sodium thiosulfate is 0.1~0.3 mol / L.
[0015] Preferably, in step (2), the reaction temperature is 60~90℃ and the reaction time is 15~35min.
[0016] Further optimization involves a reaction temperature of 70-80℃ and a reaction time of 30 minutes.
[0017] As a preferred option, the amount of composite precipitant used is 1.0 to 1.5 times the mass of nickel, iron, and copper in the copper electrolytic refining solution.
[0018] Preferably, in step (2), the three layers of the reaction product liquid are: an upper layer of iron-suspended matter, a middle layer of copper colloidal complex, and a lower layer of nickel-diethyldithiocarbamate sodium chelate precipitate.
[0019] The beneficial effects of this invention are: 1. This invention achieves highly efficient and selective separation of nickel from iron and copper by adding a composite precipitant of sodium thiosulfate and sodium diethyldithiocarbamate to the post-electrolysis solution, utilizing their synergistic effect: Sodium thiosulfate, acting as a reducing agent and coordination environment modifier, preferentially reduces ferric ions in the solution, while being oxidized itself and forming a loosely structured, easily floating upper suspension layer together with the iron hydrolysis products; simultaneously, sodium thiosulfate masks copper ions, inhibiting their precipitation with sodium diethyldithiocarbamate, allowing them to accumulate in the intermediate layer as soluble complexes or colloidal substances; Under these conditions, sodium diethyldithiocarbamate selectively reacts with unmasked nickel ions to form a dense, stable hydrophobic chelate precipitate. This precipitate settles to form a lower precipitate layer. Ultimately, the composite precipitant causes iron, copper, and nickel to form substances with significantly different physical properties (such as density and morphology). After standing, the three phases can separate spontaneously without the need for specialized extraction or separation methods to further process the mixed precipitate. In one step, nickel resources can be separated from the electrolyte and impurity precipitate. A high-purity nickel-rich precipitate can then be obtained by simple filtration.
[0020] 2. The composite precipitant of the present invention has high selectivity for nickel, thereby achieving efficient and high-quality recovery of nickel resources. The nickel resource recovery rate can reach more than 95%, and the nickel purity can reach more than 85%, meeting the requirements for further smelting.
[0021] 3. Since the composite precipitant of this invention can also form substances with iron and copper that have different properties, this invention can simultaneously recover the upper and middle layers of material, thereby recovering iron slag and copper resources while recovering nickel resources. Attached Figure Description
[0022] Figure 1 The images shown are actual pictures of the separation results of this invention. The left picture shows the liquid after copper electrolytic refining, and the right picture shows the reaction product liquid. Detailed Implementation
[0023] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments, but the scope of protection of the present invention is not limited to the content described.
[0024] Example 1 This embodiment utilizes the following method to recover nickel resources from the electrolyte after electrolysis: (1) Take 1L of the electrolytic solution after copper electrolysis (nickel concentration 15g / L, iron concentration 8g / L, copper concentration 5g / L), and add dilute sulfuric acid to adjust the pH to 5.0.
[0025] (2) Weigh out 0.15 mol of sodium thiosulfate and 0.1 mol of DDTC and add them to 1 L of water to prepare a composite precipitant (sodium thiosulfate concentration is 0.15 mol / L, DDTC concentration is 0.1 mol / L, sodium thiosulfate: sodium diethyldithiocarbamate = 1.5:1). While stirring the electrolyte, add 28 g of the composite precipitant (1 times the mass of nickel, iron, and copper in the copper electrolytic refining solution) to the electrolyte. At the same time, heat the electrolyte to 75°C. After the composite precipitant is added, continue stirring and keep warm for 30 min. Stop stirring and let stand for 1 h. The reaction product liquid forms three layers. The uppermost layer is a reddish-brown loose flocculent substance (iron-rich layer), the middle liquid phase is clear (copper-rich colloid), and the lower layer is a dark green dense precipitate (nickel-rich layer).
[0026] (3) The upper and middle liquids are recovered by decantation, and the upper, middle and lower liquids are separated. The upper liquid is vacuum filtered to obtain iron-rich flocculents, and the lower liquid is vacuum filtered to obtain nickel-rich precipitate. The nickel-rich precipitate is then washed and collected for later use.
[0027] The nickel-rich precipitate in this embodiment was tested, and the nickel resource recovery rate was calculated to be 96.5%, and the nickel content (purity) in the nickel-rich precipitate was 87.2%.
[0028] Example 2 This embodiment utilizes the following method to recover nickel resources from the electrolyte after electrolysis: (1) Take 1L of the electrolytic solution after copper electrolysis (nickel concentration 15g / L, iron concentration 8g / L, copper concentration 5g / L), and add dilute sulfuric acid to adjust the pH to 5.5.
[0029] (2) Weigh out 0.12 mol of sodium thiosulfate and 0.08 mol of DDTC and add them to 1 L of water to prepare a composite precipitant (sodium thiosulfate concentration is 0.12 mol / L, DDTC concentration is 0.08 mol / L, sodium thiosulfate: sodium diethyldithiocarbamate = 1.5:1). While stirring the electrolyte, add 33.6 g of the composite precipitant (1.2 times the mass of nickel, iron, and copper in the copper electrolytic refining solution) to the electrolyte. At the same time, heat the electrolyte to 80 °C. After the composite precipitant is added, continue stirring and keep warm for 30 min. Stop stirring and let stand for 1 h. The reaction product liquid forms three layers. The uppermost layer is a reddish-brown loose flocculent substance (iron-rich layer), the middle liquid phase is clear (copper-rich colloid), and the lower layer is a dark green dense precipitate (nickel-rich layer).
[0030] (3) The upper and middle liquids are recovered by decantation, and the upper, middle and lower liquids are separated. The upper liquid is vacuum filtered to obtain iron-rich flocculents, and the lower liquid is vacuum filtered to obtain nickel-rich precipitate. The nickel-rich precipitate is then washed and collected for later use.
[0031] The nickel-rich precipitate in this embodiment was tested, and the nickel resource recovery rate was calculated to be 95.8%, and the nickel content (purity) in the nickel-rich precipitate was 86.1%.
[0032] Example 3 This embodiment utilizes the following method to recover nickel resources from the electrolyte after electrolysis: (1) Take 1L of the electrolytic solution after copper electrolysis (nickel concentration 15g / L, iron concentration 8g / L, copper concentration 5g / L), and add dilute sulfuric acid to adjust the pH to 4.
[0033] (2) Weigh out 0.05 mol of sodium thiosulfate and 0.05 mol of DDTC and add them to 1 L of water to prepare a composite precipitant (sodium thiosulfate concentration is 0.05 mol / L, DDTC concentration is 0.05 mol / L, sodium thiosulfate: sodium diethyldithiocarbamate = 1:1). While stirring the electrolyte, add 42 g of the composite precipitant (1.5 times the mass of nickel, iron, and copper in the copper electrolytic refining solution) to the electrolyte. At the same time, heat the electrolyte to 60 °C. After the composite precipitant is added, continue stirring and keep warm for 35 min. Stop stirring and let stand for 0.5 h. The reaction product liquid forms three layers. The uppermost layer is a reddish-brown loose flocculent substance (iron-rich layer), the middle liquid phase is clear (copper-rich colloid), and the lower layer is a dark green dense precipitate (nickel-rich layer).
[0034] (3) The upper and middle liquids are recovered by decantation, and the upper, middle and lower liquids are separated. The upper liquid is vacuum filtered to obtain iron-rich flocculents, and the lower liquid is vacuum filtered to obtain nickel-rich precipitate. The nickel-rich precipitate is then washed and collected for later use.
[0035] In this embodiment, the nickel recovery rate is above 95%, and the nickel content in the nickel-rich precipitate is above 85%.
[0036] Example 4 This embodiment utilizes the following method to recover nickel resources from the electrolyte after electrolysis: (1) Take 1L of the electrolytic solution after copper electrolysis (nickel concentration 15g / L, iron concentration 8g / L, copper concentration 5g / L), and add dilute sulfuric acid to adjust the pH to 6.
[0037] (2) Weigh out 0.6 mol of sodium thiosulfate and 0.2 mol of DDTC and add them to 1 L of water to prepare a composite precipitant (sodium thiosulfate concentration is 0.6 mol / L, DDTC concentration is 0.2 mol / L, sodium thiosulfate: sodium diethyldithiocarbamate = 3:1). While stirring the electrolyte, add 28 g of the composite precipitant (1 times the mass of nickel, iron, and copper in the copper electrolytic refining solution) to the electrolyte. At the same time, heat the electrolyte to 90 °C. After the composite precipitant is added, continue stirring and keep warm for 15 min. Stop stirring and let stand for 2 h. The reaction product liquid forms three layers. The uppermost layer is a reddish-brown loose flocculent substance (iron-rich layer), the middle liquid phase is clear (copper-rich colloid), and the lower layer is a dark green dense precipitate (nickel-rich layer).
[0038] (3) The upper and middle liquids are recovered by decantation, and the upper, middle and lower liquids are separated. The upper liquid is vacuum filtered to obtain iron-rich flocculents, and the lower liquid is vacuum filtered to obtain nickel-rich precipitate. The nickel-rich precipitate is then washed and collected for later use.
[0039] In this embodiment, the nickel recovery rate is above 95%, and the nickel content in the nickel-rich precipitate is above 85%.
[0040] In summary, the method of the present invention, by adding a composite precipitant, achieves the precipitation of nickel resources in the electrolyte after electrolysis and the separation of nickel from copper and iron in one step, thereby ensuring the efficient and high-quality recovery of nickel and having good economic and environmental benefits.
[0041] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.
Claims
1. A method for recovering nickel resources from copper electrolytic refining solution, characterized in that: The method includes the following steps: (1) Filter the copper electrolytic refining solution and adjust the pH of the copper electrolytic refining solution to 4.0~6.0; (2) Add a composite precipitant to the copper electrolytic refining solution with pH=4.0~6.0 in step (1), and heat the copper electrolytic refining solution at the same time. After the reaction is completed, let the copper electrolytic refining solution stand until the reaction product liquid forms three layers. The composite precipitant is a mixed aqueous solution of sodium thiosulfate and sodium diethyldithiocarbamate; (3) The three-layer substance formed by the reaction product liquid in step (2) is recycled by layering. The bottom layer is filtered to obtain a precipitate. After washing the precipitate, the nickel resource recovery is completed.
2. The method according to claim 1, characterized in that: In step (1), sodium hydroxide or dilute sulfuric acid is used to adjust the pH of the copper electrolytic refining solution.
3. The method according to claim 1, characterized in that: In step (2), the concentration of sodium diethyldithiocarbamate in the composite precipitant is 0.05~0.2 mol / L, the concentration of sodium thiosulfate in the composite precipitant is 0.05~0.6 mol / L, and the molar ratio of sodium thiosulfate to sodium diethyldithiocarbamate in the composite precipitant is sodium thiosulfate: sodium diethyldithiocarbamate = 1:1~3:
1.
4. The method according to claim 1, characterized in that: In step (2), the reaction temperature is 60~90℃ and the reaction time is 15~35min.
5. The method according to claim 1, characterized in that: In step (2), the amount of composite precipitant used is 1.0 to 1.5 times the mass of nickel, iron, and copper in the copper electrolytic refining solution.
6. The method according to claim 1, characterized in that: In step (2), the three layers of the reaction product liquid are: the upper layer is an iron-suspended layer, the middle layer is a copper colloidal complex layer, and the lower layer is a nickel-diethyldithiocarbamate sodium chelate precipitate layer.