A process for the recovery of copper and cobalt from copper and cobalt bearing materials

Abstract

This invention belongs to the field of wet processing technology for copper-containing materials, and relates to a method for recovering copper and cobalt from copper-cobalt-containing materials. The method includes the following steps: S1, performing a first-stage atmospheric pressure leaching treatment on the copper-cobalt material to obtain a first-stage leachate and a first-stage leachate residue; S2, performing a second-stage pressure leaching treatment on the first-stage leachate residue to obtain a second-stage leachate and a second-stage leachate residue, wherein the second-stage leachate includes residual acid that was not completely reacted during the second-stage pressure leaching treatment; S3, returning the second-stage leachate to step S1 for a first-stage atmospheric pressure leaching treatment, and then sequentially performing neutralization, extraction, back-extraction, and electrowinning treatment on the first-stage leachate from step S3 to obtain electrowinning copper; S4, subjecting the copper extraction residue after extraction treatment to a cobalt precipitation reaction to obtain a cobalt product. This method, by returning the liquid after the second-stage pressure leaching in step S2 to step S1 for a second-stage atmospheric pressure leaching, significantly extracts metallic copper, metallic cobalt, and copper and cobalt elements from some copper-cobalt compounds from the copper-cobalt raw material.

Description

Technical Field

[0001] This invention belongs to the field of wet processing technology for copper-containing materials, and specifically relates to a method for recovering copper and cobalt from copper-cobalt-containing materials. Background Technology

[0002] The smelting processes for copper- and cobalt-containing materials are divided into two types: pyrometallurgical smelting and hydrometallurgical smelting. Among them, the pyrometallurgical process has high energy consumption, large equipment investment, and limited metal recovery rate. The smelting slag produced still contains a certain amount of valuable components such as Co, Cu, Fe, Si, Mg, Ca, and Al. The cobalt and copper elements that enter the smelting slag cannot be effectively recovered, thus causing a waste of copper, cobalt, and other resources.

[0003] Patent document CN116219165A discloses a method for extracting copper, manganese, and cobalt from materials containing these components. However, this method is designed for materials with specific copper and cobalt content and is unsuitable for materials with fluctuating raw material composition. In particular, the leaching effect is limited for materials with low copper and cobalt content. The cobalt precipitation solution mentioned in this patent document has a pH controlled at 7.5–8.5 during the cobalt precipitation process, resulting in very low acidity and extremely limited effect on promoting the acid leaching process. Summary of the Invention

[0004] To address the above problems, the present invention adopts the following technical solution: a method for recovering copper and cobalt from copper-cobalt-containing materials, the method comprising the following steps:

[0005] S1. Perform a first-stage atmospheric pressure leaching treatment on copper-cobalt materials to obtain a first-stage leachate and a first-stage leaching residue;

[0006] S2. Perform a second-stage pressure leaching treatment on the first-stage leaching residue to obtain a second-stage leachate and a second-stage leaching residue. The second-stage leachate includes the residual acid that was not completely reacted during the second-stage pressure leaching treatment.

[0007] S3. The second-stage leachate is returned to step S1 for a first-stage atmospheric pressure leaching. Then, the first-stage leachate in step S3 is subjected to neutralization, extraction, back-extraction and electrowinning treatment in sequence to obtain electrowinning copper.

[0008] S4. The copper leaching liquid after extraction is subjected to a cobalt precipitation reaction to obtain the cobalt product.

[0009] Further, in step S1, the conditions for the first stage of atmospheric pressure leaching treatment are: leaching temperature of 25-90℃, leaching time of 1-5h, pH of leaching solution of 2.0-4.0, and liquid-solid ratio of 1.5:1-8:1.

[0010] Further, in step S2, the two-stage pressure leaching conditions are as follows: leaching temperature is 180-240℃, leaching time is 1-5h, leaching pressure is 0.1-0.8MPa, leaching solution pH is 0.3-1.0, and liquid-solid ratio is 1.5:1-8:1.

[0011] Further, step S1 includes: mixing copper-cobalt material, sulfuric acid solution and oxidant, and performing a first-stage atmospheric pressure leaching treatment to obtain a first-stage leachate; the ratio of sulfuric acid solution to copper-cobalt material is 1.5:1 to 8:1, and the mass concentration of sulfuric acid solution is 25% to 60%; the oxidant is at least one of sulfur dioxide, flue gas containing sulfur dioxide, sodium thiosulfate, calcium sulfite, sodium sulfite, sodium metabisulfite, potassium sulfite or ammonium sulfite.

[0012] Further, step S2 includes: mixing the first-stage leaching residue with sulfuric acid solution and water, and performing a second-stage pressure leaching treatment to obtain a second-stage leachate.

[0013] Further, step S3 includes: returning the second-stage leaching solution to step S1 for a first-stage atmospheric pressure leaching, wherein the overall copper leaching rate in the first-stage leaching solution of step S3 is ≥95% and the cobalt leaching rate is ≥90%; adding a neutralizing agent to the first-stage leaching solution of step S3 to carry out a neutralization precipitation reaction, controlling the pH to 3.5-5.5 and the temperature to 40-80℃, to remove iron and aluminum from the leaching solution, so that the iron concentration in the leaching solution after removing iron and aluminum is not higher than 5 ppm and the aluminum concentration is not higher than 10 ppm; adding an extractant to the leaching solution after removing iron and aluminum, and carrying out extraction and back-extraction treatment to obtain a back-extraction solution; adding the back-extraction solution to an electrowinning system for electrowinning to obtain electrowinning copper.

[0014] Further, step S4 includes: adding a neutralizing agent to the copper extraction residue obtained in step S3 to carry out a cobalt precipitation reaction, wherein the copper content in the copper extraction residue is <50mg / L, the pH is controlled at 7.0-8.5, and the cobalt product obtained is cobalt hydroxide, wherein the cobalt concentration in the liquid after cobalt precipitation is <6mg / L.

[0015] Further, the second-stage leaching residue after the two-stage pressure leaching treatment in step S2, the iron-aluminum slag after the neutralization treatment to remove iron and aluminum in step S3, and the cobalt-precipitated liquid after the cobalt precipitation reaction in step S4 are mixed, and a neutralizing agent is added to treat and generate tailings.

[0016] Furthermore, the neutralizing agent is at least one of NaOH, MgO, CaCO3 or Ca(OH)2; the extractant consists of an amine extractant and a neutral oxygen-containing extractant.

[0017] Furthermore, the residual acid from the unreacted second-stage pressure leaching process is sulfuric acid, and the pH of the second-stage leachate is 0.3–1.0.

[0018] The advantages of this invention compared to the prior art are as follows:

[0019] (1) The method for recovering copper and cobalt from copper-cobalt materials designed in this invention has a pH of only 0.3 to 1.0 in the second-stage leaching solution in step S2, and the acidity is still very high. After returning to step S1 for another stage of atmospheric pressure leaching, the metallic copper, metallic cobalt and copper and cobalt elements in some copper-cobalt compounds in the copper-cobalt raw materials can be significantly extracted. At the same time, after the return solution is leached again under atmospheric pressure, the open-circuit solution has a higher copper and cobalt content than the solution after leaching in step S2. In addition, the residual acid in the second-stage leaching process can be recovered, realizing the recycling of the second-stage leaching solution, reducing the amount of new acid used, and reducing the overall acid consumption of the process.

[0020] (2) The method for recovering copper and cobalt from copper-cobalt-containing materials designed in this invention has strong raw material adaptability and is applicable to copper-cobalt associated raw ores, copper-cobalt concentrates, copper-cobalt smelting slags and their mixed ores with large fluctuations in copper and cobalt content and complex impurity composition; it has good inclusiveness and is applicable to copper-cobalt sulfide ores and copper-cobalt oxide ores; especially for associated materials with low copper and cobalt content, it can achieve comprehensive recovery of copper and cobalt and obtain better recovery results;

[0021] (3) The method for recovering copper and cobalt from copper-cobalt materials designed in this invention can recover various valuable metal products, such as copper and cobalt, with a comprehensive copper leaching rate of ≥95%, a comprehensive cobalt leaching rate of ≥90%, a cobalt hydroxide content of ≥40%, and a water content of ≤55%, and the recovery value is better than that of existing processes.

[0022] Other features and advantages of the invention will be set forth in the description which follows, 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 will be realized and obtained from the description and the drawings. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a flowchart of a method for recovering copper and cobalt from copper-cobalt-containing materials. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, 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.

[0026] A method for recovering copper and cobalt from copper-cobalt containing materials, such as Figure 1 As shown, it includes the following steps:

[0027] S1. Perform a first-stage atmospheric pressure leaching treatment on the copper-cobalt material to obtain a first-stage leachate and a first-stage leachate residue; S2. Perform a second-stage pressure leaching treatment on the first-stage leachate residue to obtain a second-stage leachate and a second-stage leachate residue. The second-stage leachate includes residual acid that was not completely reacted during the second-stage pressure leaching treatment; S3. Return the second-stage leachate to step S1 for a first-stage atmospheric pressure leaching treatment. Then, perform neutralization, extraction, back-extraction, and electrowinning treatment on the first-stage leachate from step S3 in sequence to obtain electrowinning copper; S4. Perform a cobalt precipitation reaction on the copper extraction residue after extraction treatment to obtain the cobalt product.

[0028] In this embodiment of the invention, step S1 includes: mixing copper-cobalt materials, sulfuric acid solution, and an oxidant, and performing a first-stage atmospheric pressure leaching treatment to obtain a first-stage leachate. The oxidant is at least one of sulfur dioxide, sulfur dioxide-containing flue gas, sodium thiosulfate, calcium sulfite, sodium sulfite, sodium metabisulfite, potassium sulfite, or ammonium sulfite. When the catalyst is sulfur dioxide gas or sulfur dioxide-containing flue gas, the sulfur dioxide needs to be mixed with one or more of oxygen, air, or an oxygen-enriched gas and introduced into the atmosphere. The volume concentration of sulfur dioxide is 0.2-3% of the total volume of the oxygen-containing gas and the sulfur dioxide gas, and the mixed gas introduction rate is 0.2-1 Nm³. 3 / m 3 Slurry·min; When the catalyst is a sulfur-containing reagent such as sodium sulfite or sodium metabisulfite, the amount of catalyst added is 0.5-5% of the mass of the copper-cobalt oxide ore.

[0029] In this embodiment of the invention, in step S1, the conditions for a first-stage atmospheric pressure leaching treatment are set as follows: leaching temperature is 25-90℃, leaching time is 1-5h, pH of leaching solution is 2.0-4.0, and liquid-solid ratio is 1.5:1-8:1.

[0030] In this embodiment of the invention, step S2 includes: mixing the first-stage leaching residue with sulfuric acid solution and water, and performing a second-stage pressure leaching treatment to obtain a second-stage leachate. The second-stage leachate includes residual acid that was not completely reacted during the second-stage pressure leaching treatment, and the pH of the second-stage leachate is 0.3 to 1.0.

[0031] In this embodiment of the invention, in step S2, the conditions for the two-stage pressure leaching treatment are set as follows: leaching temperature is 180-240℃, leaching time is 1-5h, leaching pressure is 0.1-0.8MPa, leaching solution pH is 0.3-1.0, and liquid-solid ratio is 1.5:1-8:1.

[0032] In this embodiment of the invention, a two-stage atmospheric leaching process is employed. The atmospheric leaching process removes non-minerals such as carbonates and calcium from copper-cobalt-containing materials, and simultaneously removes metallic phases from the raw materials, preventing the subsequent entry of metallic phases into the pressure vessel, which could pose an explosion hazard. In existing technologies, the recovery of copper and cobalt from copper-cobalt-containing materials often employs a single atmospheric leaching process. However, the copper and cobalt leaching rate is relatively low during this stage, especially for raw materials with low copper and cobalt content. The two-stage pressure leaching process, under pressurized and oxygenated conditions, enhances the leaching conditions and further improves the cobalt and copper leaching rate. Furthermore, the leaching solution after the two-stage pressure leaching process still retains a certain level of acidity. Recycling the leaching solution to recover residual acid (sulfuric acid solution) provides a certain amount of acid for the first-stage atmospheric leaching process of copper-cobalt slag, reducing the amount of new sulfuric acid solution added in the first-stage atmospheric leaching process, decreasing overall acid consumption, and thus lowering production costs. Simultaneously, the entire leaching solution is reused, eliminating the need for subsequent waste acid neutralization treatment. In addition, after the second stage of pressurized leaching, the returned liquid undergoes another atmospheric pressure leaching, which further enriches the copper and cobalt elements in the raw material in the liquid phase. This can further increase the concentration of copper and cobalt in the leaching liquid, which is convenient for subsequent copper extraction and cobalt precipitation, and at the same time improves the overall copper and cobalt recovery rate of the process.

[0033] In this embodiment of the invention, step S3 includes: returning the second-stage leaching solution to the leaching solution after the first-stage atmospheric pressure leaching in step S1, adding a neutralizing agent to perform a neutralization and precipitation reaction, controlling the pH to 3.5–5.5, removing iron and aluminum from the leaching solution, ensuring that the iron concentration in the leaching solution after iron and aluminum removal is no higher than 5 ppm and the aluminum concentration is no higher than 10 ppm; then adding an extractant to the leaching solution after iron and aluminum removal, performing extraction and back-extraction treatment to obtain a back-extraction solution; adding the back-extraction solution to an electrowinning system for electrowinning to obtain electrowinning copper. The overall copper leaching rate in the first-stage leaching solution in step S3 is ≥95%, and the cobalt leaching rate is ≥90%.

[0034] In this embodiment of the invention, step S3, during the copper extraction process, uses an organic phase comprising a copper extractant and a diluent. The copper extractant consists of an amine extractant and a neutral oxygen-containing extractant, with an alcohol reagent used as a phase modifier, and aviation kerosene, 260# solvent oil (sulfonated kerosene), or Escaid 100 used as a diluent. After extraction, the copper-rich organic phase is washed with an aqueous phase and then back-extracted using a copper electrodeposition anolyte. The back-extracted anolyte, i.e., the back-extracted solution, enters the electrodeposition system for electrodeposition to obtain electrodeposited copper; while the raffinate undergoes the subsequent cobalt precipitation reaction. Using the above-mentioned copper extractant for extraction-back-extraction improves the copper extraction efficiency, enriches copper, and ensures that only a small amount of copper enters the raffinate.

[0035] In this embodiment of the invention, step S4 includes: adding a neutralizing agent to the copper extraction residue obtained in step S3 to carry out a cobalt precipitation reaction. The copper content in the copper extraction residue is <50mg / L, the pH is controlled at 7.0-8.5, and the cobalt product obtained is cobalt hydroxide. The cobalt concentration in the liquid after cobalt precipitation is <6mg / L.

[0036] In addition, the second-stage leaching residue after the two-stage pressure leaching treatment in step S2, the iron-aluminum slag after the neutralization treatment to remove iron and aluminum in step S3, and the cobalt-precipitated liquid after the cobalt precipitation reaction in step S4 are mixed and treated with a neutralizing agent to generate tailings.

[0037] In step S3 or step S4 above, or in the process of generating tailings treatment, the neutralizing agent selected is at least one of NaOH, MgO, CaCO3 or Ca(OH)2.

[0038] It should be noted that the core of this invention lies in subjecting the leaching residue from the first stage of atmospheric leaching to a second stage of pressure leaching. This second-stage pressure leaching further extracts valuable copper and cobalt metals from the raw materials. Simultaneously, unreacted sulfuric acid from the second-stage pressure leaching can be recovered and recycled back to the first stage of atmospheric leaching. This recycled residual acid is then used in the next batch of copper- and cobalt-containing materials for another stage of atmospheric leaching during production. This reduces sulfuric acid consumption throughout the process, thereby lowering production costs to some extent. Furthermore, the sulfuric acid in the entire process does not require a subsequent acid neutralization treatment device, reducing post-processing costs. After the liquid from the second-stage pressure leaching is returned for another atmospheric leaching, the concentration of copper and cobalt in the liquid phase can be further increased, facilitating subsequent copper extraction and cobalt precipitation reactions and improving the overall recovery rate of copper and cobalt.

[0039] The present invention will be further described below with reference to specific embodiments:

[0040] The composition of the copper and cobalt raw materials used in the examples is shown in Table 1 below.

[0041] Table 1 Composition of Copper and Cobalt Raw Materials

[0042] element Co Cu Fe Al Ca Mg Si S Copper-cobalt slag content / % 1.59 6.10 31.22 0.87 0.67 0.44 10.48 1.65

[0043] Example 1

[0044] 100g of copper-cobalt ore smelting slag (its composition is shown in Table 1) was weighed, and 15g of concentrated sulfuric acid and 500g of water were added. A mixture of SO2 and air was introduced for a first-stage atmospheric pressure leaching at 50℃ for 3 hours, maintaining the pH of the leaching system at 3.1–3.3 and the liquid-to-solid ratio at 5:1. The leaching solution and residue were obtained after filtration. The residue was then mixed with 25g of sulfuric acid and 275g of water for a second-stage pressure leaching at 220℃, with an oxygen partial pressure of 0.5MPa for 2 hours, maintaining the pH of the leaching system at 0.5–0.6 and the liquid-to-solid ratio at 6:1. The second-stage leaching solution and residue were obtained after filtration. After the two-stage leaching, the copper leaching rate was 91%, and the overall cobalt leaching rate was 95.3%.

[0045] The second-stage leaching solution was returned to the first-stage atmospheric pressure leaching. 100g of copper-cobalt ore smelting slag, appropriate amount of water and sulfuric acid were added. The pH of the leaching system was controlled at 3.1-3.3, the liquid-solid ratio was 5:1, and the leaching temperature was 50℃. After atmospheric pressure leaching, the first-stage leaching solution and the first-stage leaching slag were obtained by filtration. The overall copper leaching rate was 96%, and the overall cobalt leaching rate was 97.5%.

[0046] Electrodegraded copper was obtained by neutralizing and precipitating a leachate, followed by extraction, back-extraction, and electrowinning. The neutralizing agent was CaCO3, and the pH was controlled at 4.6 and the temperature at 70℃ during the neutralization and precipitation reaction to ensure that the iron concentration in the leachate after iron and aluminum removal was no higher than 5 ppm and the aluminum concentration no higher than 10 ppm. The extractant was Lix984N. Calcium carbonate was added to the copper leaching residue after extraction to neutralize the residue and induce a cobalt precipitation reaction. The copper content in the residue was 45 mg / L, and the pH was controlled at 7.8. The resulting cobalt product was cobalt hydroxide, with a cobalt concentration of 5 mg / L in the precipitated solution. The cobalt hydroxide contained 40% cobalt and had a water content of 53%.

[0047] The difference between Examples 2 and 3 and Example 1 is that the process parameters are different, but the method steps are the same; the copper and cobalt leaching rates and the product indicators of cobalt hydroxide are shown in Table 1.

[0048] The difference between Example 4 and Example 1 is that the raw material composition is different, but the method steps are the same; the copper and cobalt leaching rates and the product indicators of cobalt hydroxide are shown in Table 1.

[0049] The difference between Comparative Example 1 and Example 1 is that only one stage of atmospheric pressure leaching was performed, without the second stage of pressurized leaching. The leaching rate indicators for copper and cobalt are shown in Table 1.

[0050] The difference between Comparative Example 2 and Example 1 is that only one stage of atmospheric pressure leaching and two stages of pressurized leaching were performed, and the second stage leachate was not returned to step S1 for one stage of atmospheric pressure leaching. The copper and cobalt leaching rate indicators are shown in Table 2.

[0051] Table 2. Relevant data for Examples 1-4 and Comparative Examples 1-2

[0052]

[0053]

[0054] Based on the copper-cobalt leaching rates of Example 1 and Comparative Example 2, it can be seen that after the liquid is returned to the liquid phase and then subjected to atmospheric pressure leaching again after two-stage pressure leaching, the concentration of copper and cobalt in the liquid phase can be further increased (the comprehensive leaching rates of copper and cobalt in Example 1 were 96.08% and 97.51%, respectively; the comprehensive leaching rates of copper and cobalt in Comparative Example 2 were 91.39% and 93.33%, respectively). Based on Example 1 and Comparative Example 1, it can be seen that the two-stage pressure leaching process, under pressure and oxygenation conditions, can further improve the leaching rates of cobalt and copper by strengthening the leaching conditions (the comprehensive leaching rates of copper and cobalt in Example 1 were 96.08% and 97.51%, respectively; the comprehensive leaching rates of copper and cobalt in Comparative Example 1 were 58.27% and 42.01%, respectively).

[0055] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for recovering copper and cobalt from copper-cobalt-containing materials, characterized in that, The method includes the following steps: S1. Copper-cobalt material, sulfuric acid solution, sulfur dioxide and air are mixed and subjected to a first-stage atmospheric pressure leaching treatment. The first-stage atmospheric pressure leaching treatment conditions are: leaching temperature of 60℃, leaching time of 2h, pH of leaching solution of 2.5~2.8, and liquid-solid ratio of 8:1, to obtain a first-stage leaching solution and a first-stage leaching residue. S2. The first-stage leaching residue is mixed with sulfuric acid solution and water, and subjected to a second-stage pressure leaching treatment. The conditions for the second-stage pressure leaching treatment are: leaching temperature of 220℃, leaching time of 4h, leaching pressure of 0.5MPa, pH of leaching solution of 0.3~0.4, and liquid-solid ratio of 8:1, to obtain a second-stage leaching solution and a second-stage leaching residue. The second-stage leaching solution includes residual acid that was not completely reacted during the second-stage pressure leaching treatment, and the pH of the second-stage leaching solution is 0.3~0.

4. S3. Return the second-stage leachate to step S1 for a first-stage atmospheric pressure leaching treatment. Then, add a neutralizing agent to the first-stage leachate from step S3 to carry out a neutralization and precipitation reaction, controlling the pH to 3.5~5.5 and the temperature to 40~80℃ to remove iron and aluminum from the leachate, ensuring that the iron concentration in the leachate after iron and aluminum removal is no higher than 5 ppm and the aluminum concentration is no higher than 10 ppm. Add an extractant to the leachate after iron and aluminum removal for extraction and back-extraction treatment to obtain a back-extraction solution. Add the back-extraction solution to an electrowinning system for electrowinning to obtain electrowinning copper. S4. Add a neutralizing agent to the copper leaching liquid after extraction to carry out a cobalt precipitation reaction. The copper content in the copper leaching liquid is <50 mg / L, and the pH is controlled at 7.0~8.

5. The cobalt product obtained is cobalt hydroxide, and the cobalt concentration in the liquid after cobalt precipitation is <6 mg / L.

2. The method according to claim 1, characterized in that, The leaching residue after the two-stage pressure leaching treatment in step S2, the iron-aluminum slag after the neutralization treatment to remove iron and aluminum in step S3, and the cobalt-precipitated liquid after the cobalt precipitation reaction in step S4 are mixed and treated with a neutralizing agent to generate tailings.

3. The method according to claim 1 or 2, characterized in that, The neutralizing agent is at least one of NaOH, MgO, CaCO3 or Ca(OH)2; the extractant consists of an amine extractant and a neutral oxygen-containing extractant.

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