CN113832344B - Method for recovering copper and cobalt from copper-cobalt slag - Google Patents

Abstract

The invention belongs to the technical field of wet metallurgy, and particularly relates to a method for recovering copper and cobalt from copper-cobalt slag, which comprises the following steps: step (1): carrying out selective oxidation leaching on copper-cobalt slag and an oxidant in a methanesulfonic acid solution system, and then carrying out solid-liquid separation to obtain a copper-cobalt methanesulfonic acid leaching solution and metal impurity slag; step (2): and (4) performing electric replacement treatment on the copper-cobalt methanesulfonic acid leaching solution, and separating to obtain copper sponge and copper-cobalt removal solution. Compared with the traditional sulfuric acid system, the method selects methanesulfonic acid as the reaction system, can effectively realize the selective separation of each metal in the copper-cobalt slag, improves the recovery efficiency of copper and cobalt, and provides guidance for industrial production.

Description

A kind of method for recovering copper and cobalt from copper-cobalt slag

technical field

The invention relates to a method for recovering copper and cobalt from copper-cobalt slag, belonging to the technical field of hydrometallurgy.

Background technique

In the hydrometallurgical system, copper-cobalt sulfide or oxide slag will be produced, and the copper-cobalt in the slag has a high recovery value. Therefore, the efficient resource utilization of copper-cobalt slag has significant economic and social benefits.

In order to realize the effective extraction and separation of valuable elements of copper-cobalt slag, many experts and scholars in my country have also done a lot of research work on the disposal of copper-cobalt slag. For example, Liao Chunfa et al. adopted the selective leaching of copper and cobalt - leaching solution to extract copper and electrowinning to produce cathode copper - raffinate oxidation neutralization and iron removal - the process flow of liquid neutralization of cobalt precipitation to produce cobalt slag after iron removal from copper-cobalt oxide ore Recycling and separating copper and cobalt can make the copper leaching rate greater than 95% and the cobalt leaching rate greater than 88%. Tang Chaobo et al. used pyroreduction smelting to treat copper-cobalt smelting slag. Under the optimal process conditions of coke consumption of 6%, pyrite consumption of 20%, smelting temperature of 1350°C, and holding time of 3h, the highest recovery rate of copper and cobalt was 92.95% and 89.95%.

Although the above method has a good recovery effect on copper and cobalt in the slag, the recovery efficiency is still unsatisfactory. In addition, due to the particularity of the slag, it contains a large number of interfering impurity elements similar to copper and cobalt. The existence of serious interference with the extraction selectivity of copper and cobalt, to a large extent, leads to a decrease in the grade of the obtained product. Therefore, there is an urgent need in the industry for a technical solution that can extract copper and cobalt from impurity elements with high selectivity and achieve high-selectivity separation of copper and cobalt.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a method for recovering copper and cobalt from copper-cobalt slag, aiming at improving the separation selectivity of copper-cobalt and impurity elements, and improving the separation selectivity of copper and cobalt.

A method for recovering copper and cobalt from copper-cobalt slag, comprising the following steps:

Step (1): carry out selective oxidative leaching of copper-cobalt slag and oxidant in methanesulfonic acid (also referred to as methanesulfonic acid or CH ₃ SO ₃ H in the present invention) solution system, followed by solid-liquid separation to obtain copper-cobalt methyl methacrylate. Sulfonic acid leaching solution and metal impurity slag; in the methanesulfonic acid solution, the concentration of methanesulfonic acid is 80-150 g/L;

Step (2): subject the copper-cobalt methanesulfonic acid leaching solution to electro-replacement treatment to separate the sponge copper and decopper-decobalt solution; wherein, the current density during the electro-replacement process is 10-30 mA/cm ² .

In addition to copper and cobalt, copper-cobalt slag also contains a large amount of impurity elements. The properties of these impurity elements are mostly similar to those of copper and cobalt, which will be accompanied by leaching of copper and cobalt to a large extent, resulting in difficulty in selective separation; in addition, The phase types of copper-cobalt slag are complex, and the leaching behavior of each phase is different, which will also greatly affect the leaching and recovery of copper and cobalt. In order to solve the problem of the unsatisfactory recovery rate of copper and cobalt in the copper-cobalt slag and the separation selectivity of copper and cobalt from interfering impurity elements, the present invention innovatively finds that oxidative leaching is carried out under the methanesulfonic acid system, and the control of the described conditions is carried out, The problem of selectivity between copper-cobalt and impurity elements in the slag can be unexpectedly improved, and the simultaneous, high-selectivity, and high-recovery leaching of copper-cobalt can be unexpectedly realized. Not only that, on the basis of the innovative high-selective leaching of methanesulfonic acid, the electro-displacement reaction under the methanesulfonic acid system and the combined control of electro-displacement conditions can further synergistically improve copper and cobalt, as well as copper and other The separation selectivity of impurity elements can further improve the recovery rate of copper, which helps to obtain high-quality cobalt while obtaining high-quality copper.

The copper-cobalt slag contains copper, cobalt and metal impurity elements; the metal impurity element contains at least one of iron, lead and antimony.

Preferably, the copper content is 10% to 30%, and the cobalt content is 1% to 10%, and the content of each metal impurity (single metal impurity) is not higher than 5% (that is, the single largest impurity is not higher than 5%) . Said content refers to the weight percent content of metals based on the dry weight of the slag.

The copper-cobalt slag can be dried, crushed, ball milled, screened and other treatments based on existing equipment and means before being treated.

The technical solution of the present invention is to carry out oxidative leaching under the innovative methanesulfonic acid system, which can unexpectedly realize the simultaneous leaching of copper and cobalt, not only that, but also can improve the separation selectivity of copper, cobalt and impurity elements, and can effectively Improve the recovery rate of copper and cobalt, and reduce the accompanying leaching rate of impurities. The study further found that controlling the concentration of methanesulfonic acid in the selective oxidative leaching process can help to further improve the separation selectivity of copper and cobalt from impurities.

Preferably, in the methanesulfonic acid solution, the concentration of methanesulfonic acid is 80-150 g/L; preferably 80-120 g/L;

The solid-liquid mass ratio of the copper-cobalt slag to the methanesulfonic acid solution is 1:4-8.

Preferably, the oxidant is hydrogen peroxide.

Preferably, the oxidizing agent is not lower than the theoretical amount for completely leaching copper and cobalt therein; preferably, it is 1.2 to 1.5 times the theoretical amount.

Preferably, the temperature of the selective oxidative leaching process is 30-90°C, preferably 80-90°C. The leaching time is preferably 0.5 to 3 hours.

The invention also finds that the innovative electro-replacement under the methanesulfonic acid system can improve the separation selectivity of copper and cobalt, as well as the separation selectivity of copper and other impurity elements, which is helpful to further improve the quality of the obtained copper. , to reduce the concomitant replacement of cobalt and impurity elements. On this basis, the selective oxidative leaching under the methanesulfonic acid system is further coordinated, which can synergistically improve the separation selectivity of copper, cobalt and other impurity elements.

Preferably, the copper cobalt methanesulfonic acid leaching solution is used as the replacement stock solution (also referred to as electrolyte or electrodeposition solution in the present invention); the metal plate is used as the anode, and the inert electrode is used as the cathode, immersed in the replacement stock solution, and energized for electric replacement.

Preferably, the metal sheet is zinc and/or iron.

Inert cathodes are graphite, titanium mesh or stainless steel plates.

The area of the cathode and anode plates may be the same or different, and preferably, the area ratio of the cathode and anode plates is preferably 1:1.

The distance between the plates is 2 to 5 cm.

Further research in the present invention finds that controlling the concentration, current density and temperature of methanesulfonic acid in the electro-displacement process helps to further improve the separation selectivity of copper, cobalt and other impurity elements, and helps to further improve the electro-displacement effect.

Preferably, in step (2), the concentration of methanesulfonic acid in the copper-cobalt methanesulfonic acid leaching solution is controlled to be 20-80 g/L, preferably 30-70 g/L.

Preferably, the pH of the electro-displacement starting solution is adjusted to be 0.2-3.

Preferably, the current density during the electro-replacement process is 10-30 mA/cm ² ; more preferably 10-20 mA/cm ² ; still more preferably 15-20 mA/cm ² .

Preferably, the temperature of the electric displacement process is 30-80°C; more preferably, it is 50-70°C.

In the present invention, based on the selective oxidative leaching and electric displacement of methanesulfonic acid, copper can be separated with high recovery rate and high selectivity, and high-quality cobalt liquid can be obtained. The cobalt solution is processed to recover the cobalt contained therein.

Preferably, the obtained copper removal cobalt solution is subjected to a precipitation reaction with oxalic acid, and then calcined to obtain Co ₃ O ₄ .

Preferably, in the process of precipitating and recovering cobalt, methanesulfonic acid solution is used to adjust the pH value of the reaction end point to 1 to 3, the amount of oxalic acid added is 1.2 to 1.5 times the theoretical amount, and the precipitation time is 0.5 to 3 hours.

Preferably, the temperature in the precipitation reaction is 50 to 70°C.

A preferred method for recovering copper and cobalt from copper-cobalt slag of the present invention comprises the following steps:

(1) The copper-cobalt slag is a moist agglomerate. After crushing, drying, ball milling, and screening, it is mixed with methanesulfonic acid solution for acid leaching. The oxidant is added during the leaching process, and the copper-cobalt and impurity metals are effectively realized by controlling the leaching process conditions. The methanesulfonate solution containing copper and cobalt and the leaching slag containing metal impurities such as iron, lead and antimony are obtained by vacuum filtration.

(2) The methanesulfonic acid salt solution containing copper and cobalt obtained in step (1) is used as the replacement stock solution. According to the standard electrode potential between metals, take the metal plate as the anode and the inert electrode as the cathode, immerse in the replacement stock solution, control the replacement parameters and start the reaction for 1-2 hours after electrification, to obtain high-purity sponge copper and cobalt-containing copper removal solution.

(3) heating the cobalt-containing copper removal solution obtained in step (2) to 50-70° C., slowly adding oxalic acid in the stirring process to obtain cobalt oxalate precipitation, and calcining cobalt oxalate at high temperature to obtain Co ₃ O ₄ .

Beneficial effects of the present invention:

1. The present invention innovatively finds that oxidative leaching under the methanesulfonic acid organic acid system can unexpectedly improve the separation selectivity of copper-cobalt and iron-lead-antimony and other impurity metals in the copper-cobalt slag, and can realize the synchronization of copper and cobalt, High selective leaching, and reduce the accompanying leaching rate of impurity metals such as iron, lead and antimony. The study found that compared with the traditional sulfuric acid system, the selective separation of metals is more effectively achieved; the whole process adopts methanesulfonic acid organic system, which is green and environmentally friendly, and is less corrosive to equipment, and at the same time, the metal recovery efficiency is higher.

2. The electro-displacement is innovatively carried out under the methanesulfonic acid system, which helps to improve the electro-displacement separation selectivity of copper and cobalt thanks to the methanesulfonic acid system. The enhanced electric displacement copper extraction of the invention reduces the consumption of raw materials in the traditional displacement process, and the displacement process controls various process parameters of the reaction, the obtained sponge copper has a purity of more than 98%, and the current efficiency and metal recovery rate are greatly improved.

3. Electro-replacement is carried out in the innovative methanesulfonic acid system, and the combined control of the methanesulfonic acid system, current density and temperature of the system can further improve the separation selectivity of copper and other metals.

4. Based on the innovative combination of methanesulfonic acid selective oxidative leaching and methanesulfonic acid electro-displacement, it can further synergize, improve the separation selectivity of copper and cobalt, and help to improve the quality of copper and cobalt recovered.

5. The study found that in the copper-cobalt slag, copper products and cobalt products can be obtained with high selectivity, and the grades of the respective products can reach more than 98%, and the recovery rate can reach more than 93%.

6. The whole process of the present invention has the advantages of simple operation, low energy consumption, and high quality of the obtained product, so that the copper and cobalt in the copper-cobalt slag can be effectively separated and efficiently recovered. In addition, there is no equipment corrosion problem in the treatment process, which is green and efficient, and is conducive to the comprehensive utilization of resources.

Description of drawings

Accompanying drawing 1 is the flow chart that the present invention recovers copper-cobalt from copper-cobalt slag under methanesulfonic acid system.

(1) and (2) in Fig. 2 are SEM images of sponge copper.

Detailed ways

The present invention will be further described below in conjunction with examples.

In the following cases, the metal content in the slag refers to the weight percent content of each metal based on the dry weight of the slag.

Example 1:

(1) Crushing, drying, ball milling, sieving to -200～-170 mesh, weighing 100g Liquid-solid ratio of 5:1 was mixed with 80g/L methanesulfonic acid solution for acid leaching, H ₂ O ₂ was added at a flow rate of 1 mL/min, and the stirring speed was 300 r/min. The methanesulfonate solution containing copper and cobalt was obtained by filtration. At this time, the leaching rates of copper and cobalt were 96.31% and 94.52% respectively, while the leaching rates of iron, lead and antimony were 1.20%, 1.38% and 0.74%. The separation effect of impurities such as lead and antimony is good. Compared with the existing inorganic acid leaching or ammonia leaching, the leaching rate and leaching selectivity of copper and cobalt are improved.

(2) Taking the methanesulfonic acid salt solution containing copper and cobalt obtained in step (1) as the replacement stock solution (adjusting pH=1.0), taking 400 mL of this solution and placing it in a 500 mL reaction tank, wherein the methanesulfonic acid concentration is 50 g/L. Use a wire to connect the metal zinc plate (size 2mm×70mm×120mm) to the positive electrode of the DC stabilized power supply, and the titanium mesh (size 70mm×120mm, mesh 2×7mm) to connect to the negative electrode of the power supply, and immerse the two-pole plate in the solution. Carry out the experimental operation, scraping off the cathodic and anodic deposits at regular intervals. The distance between the two polar plates is 3cm, the current density is 10mA/cm ² , the reaction tank is placed in a constant temperature water bath, the reaction temperature is controlled to 50°C, the reaction time is 2h, the copper replacement rate is 93.14%, and the purity of the sponge copper is 98.35%. The content of iron, lead, antimony and cobalt in the sponge copper is 0.26%, 0.37%, 0.12% and 0.09% respectively. The titanium mesh is soaked in waste acid after use, and the zinc plate can be used repeatedly until it dissolves.

(3) heating the decopper solution obtained in step (2) to 50°C, slowly adding 5.63 g of oxalic acid in the process of stirring at 200 r/min, after 2 h of precipitation, adjusting the pH value of the reaction end point to 2.0 with methanesulfonic acid solution to obtain cobalt-containing 8.93 g of cobalt oxalate was precipitated, and the total recovery rate of cobalt was 93.64%.

Comparative Example 1:

Compared with Example 1, the only difference is that the methanesulfonic acid used in the treatment process is replaced with sulfuric acid, and other operations such as the acid concentration are the same.

The result is:

In step (1), the leaching rates of copper and cobalt are 93.83% and 91.43%, respectively, and the leaching rates of iron, lead and antimony are 7.20%, 8.19% and 5.47%. The replacement rate of copper in the electrical replacement process was 91.32%, and the purity of the sponge copper was 92.14%. Compared with Example 1, the leaching rate of copper and cobalt decreased, while the leaching rate of metal impurities such as iron, lead, and antimony increased, and the recovered metal and the impurity metal were not effectively separated, resulting in a subsequent drop in the grade of sponge copper.

Example 2:

(1) Crushing, drying, ball milling, sieving to -200～-170 mesh, weighing 100g Liquid-solid ratio of 5:1 was mixed with 90g/L methanesulfonic acid solution for acid leaching, H ₂ O ₂ was added at a flow rate of 1 mL/min, and the stirring speed was 300 r/min. The methanesulfonate solution containing copper and cobalt was obtained by filtration. At this time, the leaching rates of copper and cobalt were 97.58% and 94.72% respectively, and the leaching rates of iron, lead and antimony were 1.06%, 1.43% and 0.65%. The separation effect of impurities such as antimony is good.

(2) Taking the methanesulfonic acid salt solution containing copper and cobalt obtained in step (1) as the replacement stock solution (adjusting pH=1.0), taking 400 mL of this solution and placing it in a 500 mL reaction tank, wherein the methanesulfonic acid concentration is 30 g/L using a wire Connect the metal zinc plate (size 2mm×70mm×120mm) to the positive electrode of the DC stabilized power supply, connect the titanium mesh (size 70mm×120mm, mesh 2×7mm) to the negative electrode of the power supply, immerse the two-pole plate in the solution, and conduct the experiment under the action of electricity operation, scraping off cathodic and anodic deposits at regular intervals. The distance between the two polar plates is 3cm, the current density is 15mA/cm ² , the reaction tank is placed in a constant temperature water bath, the reaction temperature is controlled to be 60°C, the reaction time is 2h, the copper replacement rate is 94.26%, and the purity of the sponge copper is 99.10%. The content of iron, lead, antimony and cobalt in the sponge copper are 0.20%, 0.28%, 0.15% and 0.07% respectively). The titanium mesh is soaked in waste acid after use, and the zinc plate can be used repeatedly until it dissolves.

(3) heating the decopper solution obtained in step (2) to 70°C, slowly adding 5.78g oxalic acid in the process of stirring at 200r/min, after 1.5h precipitation, adjusting the pH value of the reaction end point to 2.0 with methanesulfonic acid solution to obtain oxalic acid 9.01 g of cobalt was precipitated, and the total recovery rate of cobalt was 93.86%.

Example 3:

(1) Crushing, drying, ball milling, sieving to -200～-170 mesh, weighing 100g Liquid-solid ratio of 5:1 was mixed with 80 g/L methanesulfonic acid solution for acid leaching, H ₂ O ₂ was added at a flow rate of 1 mL/min, and the stirring speed was 300 r/min. The methanesulfonate solution containing copper and cobalt was obtained by filtration. At this time, the leaching rates of copper and cobalt were 96.45% and 93.61% respectively, and the leaching rates of iron, lead and antimony were 0.81%, 0.75% and 0.63%. The separation effect of impurities such as antimony is good.

(2) Taking the methanesulfonic acid salt solution containing copper and cobalt obtained in step (1) as the replacement stock solution (adjusting pH=2.0), taking 400 mL of this solution and placing it in a 500 mL reaction tank, wherein the methanesulfonic acid concentration is 40 g/L. Use a wire to connect the metal zinc plate (size 2mm×70mm×120mm) to the positive electrode of the DC stabilized power supply, and the titanium mesh (size 70mm×120mm, mesh 2×7mm) to connect to the negative electrode of the power supply, and immerse the two-pole plate in the solution. Carry out the experimental operation, scraping off the cathodic and anodic deposits at regular intervals. The distance between the two polar plates is 3cm, the current density is 15mA/cm ² , the reaction tank is placed in a constant temperature water bath, the reaction temperature is controlled to 60°C, the reaction time is 2h, the copper replacement rate is 94.48%, and the purity of the sponge copper is 98.72%. The content of iron, lead, antimony and cobalt in sponge copper are 0.23%, 0.35%, 0.14% and 0.11% respectively). The titanium mesh is soaked in waste acid after use, and the zinc plate can be used repeatedly until it dissolves.

(3) heating the decopper solution obtained in step (2) to 70°C, slowly adding 5.83 g of oxalic acid during stirring at 200 r/min, and precipitating for 1.5 h, adjusting the pH value of the reaction end point to 2.0 with methanesulfonic acid solution to obtain oxalic acid 9.12 g of cobalt was precipitated, and the total recovery rate of cobalt was 93.79%.

Example 4:

(1) The copper-cobalt slag (containing 18.14% copper, 5.38% cobalt, 1.23% iron, 3.17% lead, and 0.69% antimony) with a different content from Example 1-3 is crushed, dried, ball milled, and sieved to -200 After ～-170 mesh, weigh 100 g of mixed acid leaching with 80 g/L methanesulfonic acid solution at a liquid-solid ratio of 5:1, add H ₂ O ₂ at a flow rate of 1 mL/min, stir at a speed of 300 r/min, and at a temperature of 70 After reaction leaching at ℃ for 1 h, the methanesulfonate solution containing copper and cobalt was obtained by vacuum filtration. At this time, the leaching rates of copper and cobalt were 96.72% and 94.08%, respectively, and the leaching rates of iron, lead and antimony were 0.72% and 0.77%. , 0.56%, and the separation effect of impurities such as copper, cobalt and iron, lead and antimony is good.

(2) Taking the methanesulfonic acid salt solution containing copper and cobalt obtained in step (1) as the replacement stock solution (adjusting pH=2.0), taking 400 mL of this solution and placing it in a 500 mL reaction tank, wherein the methanesulfonic acid concentration is 40 g/L. Use a wire to connect the metal zinc plate (size 2mm×70mm×120mm) to the positive electrode of the DC stabilized power supply, and the titanium mesh (size 70mm×120mm, mesh 2×7mm) to connect to the negative electrode of the power supply, and immerse the two-pole plate in the solution. Carry out the experimental operation, scraping off the cathodic and anodic deposits at regular intervals. The distance between the two polar plates is 3cm, the current density is 15mA/cm ² , the reaction tank is placed in a constant temperature water bath, the reaction temperature is controlled to 60°C, the reaction time is 2h, the copper replacement rate is 95.24%, and the purity of the sponge copper is 98.71%. The content of iron, lead, antimony and cobalt in the sponge copper is 0.24%, 0.33%, 0.10% and 0.12% respectively. The titanium mesh is soaked in waste acid after use, and the zinc plate can be used repeatedly until it dissolves.

(3) heating the decopper solution obtained in step (2) to 70°C, slowly adding 7.43g of oxalic acid in the process of stirring at 200r/min, after 1.5h of precipitation, adjusting the pH value of the reaction end point to 2.0 with methanesulfonic acid solution to obtain oxalic acid 12.16g of cobalt was precipitated, and the total recovery rate of cobalt was 93.82%.

Example 5:

Adjust the selective leaching conditions, specifically:

(1) Crushing, drying, ball milling, sieving to -200～-170 mesh, weighing 100g The liquid-solid ratio of 5:1 was mixed with 120g/L methanesulfonic acid solution for acid leaching, H ₂ O ₂ was added at a flow rate of 1 mL/min, the stirring speed was 300 r/min, and the reaction was leached at a temperature of 80 ° C for 1 hour, and then vacuumed. The methanesulfonate solution containing copper and cobalt was obtained by filtration. At this time, the leaching rates of copper and cobalt were 98.68% and 96.37% respectively, and the leaching rates of iron, lead and antimony were 1.03%, 1.28% and 0.47%. The separation effect of impurities such as antimony is good.

(2) Taking the methanesulfonic acid salt solution containing copper and cobalt obtained in step (1) as the replacement stock solution (adjusting pH=1.0), taking 400 mL of this solution and placing it in a 500 mL reaction tank, wherein the methanesulfonic acid concentration is 40 g/L. Use a wire to connect the metal zinc plate (size 2mm×70mm×120mm) to the positive electrode of the DC stabilized power supply, and connect the titanium mesh (size 70mm×120mm, mesh 2×7mm) to the negative electrode of the power supply, and immerse the two-pole plate in the solution. Carry out the experimental operation, scraping off the cathodic and anodic deposits at regular intervals. The distance between the two polar plates is 3cm, the current density is 15mA/cm ² , the reaction tank is placed in a constant temperature water bath, the reaction temperature is controlled to be 60°C, the reaction time is 2h, the copper replacement rate is 94.52%, and the purity of the sponge copper is 98.81%. The content of iron, lead, antimony and cobalt in sponge copper is 0.21%, 0.32%, 0.11% and 0.09% respectively. The titanium mesh is soaked in waste acid after use, and the zinc plate can be used repeatedly until it dissolves.

(3) heating the decopper solution obtained in step (2) to 70°C, slowly adding 5.75g oxalic acid during stirring at 200 r/min, and precipitating for 1.5 hours, adjusting the pH value of the reaction end point to 2.0 with methanesulfonic acid solution to obtain oxalic acid 9.10 g of cobalt was precipitated, and the total recovery rate of cobalt was 94.01%.

Example 6:

Compared with Example 5, the main difference is that the selective electrical displacement conditions are adjusted, specifically:

(1) step (1) with embodiment 5.

(2) Taking the methanesulfonic acid salt solution containing copper and cobalt obtained in step (1) as the replacement stock solution, 400 mL of this solution was taken and placed in a 500 mL reaction tank, wherein the methanesulfonic acid concentration was 60 g/L. Use a wire to connect the metal zinc plate (size 2mm×70mm×120mm) to the positive electrode of the DC stabilized power supply, and the titanium mesh (size 70mm×120mm, mesh 2×7mm) to connect to the negative electrode of the power supply, and immerse the two-pole plate in the solution. Carry out the experimental operation, scraping off the cathodic and anodic deposits at regular intervals. The distance between the two polar plates is 3cm, the current density is 15mA/cm ² , the reaction tank is placed in a constant temperature water bath, the reaction temperature is controlled to be 70°C, the reaction time is 2h, the copper replacement rate is 95.87%, and the purity of the sponge copper is 98.86%. The content of iron, lead, antimony and cobalt in sponge copper is 0.19%, 0.24%, 0.08% and 0.07% respectively. The titanium mesh is soaked in waste acid after use, and the zinc plate can be used repeatedly until it dissolves.

(3) heating the copper removal solution obtained in step (2) to 70°C, slowly adding 5.73 g of oxalic acid in the process of stirring at 200 r/min, after 1.5 h of precipitation, adjusting the pH value of the reaction end point with methanesulfonic acid solution to 2.0 to obtain oxalic acid 9.17g of cobalt was precipitated, and the total recovery rate of cobalt was 93.97%.

Comparative Example 2

Compared with Example 6, the difference is only that the methanesulfonic acid used in step (2) is replaced with sulfuric acid, and other operations such as the acid concentration are the same.

The result is:

The replacement rate of copper in the electrical replacement process was 91.71%, and the purity of the sponge copper was 92.51%. Compared with Example 6, the replacement rate and purity of sponge copper decreased, and the content of impurity ions increased.

Comparative Example 3

Compared with Example 6, the only difference is that the concentration of methanesulfonic acid used in the leaching in step (1) is 50 g/L, and other operations are the same.

The result is:

In step (1), the leaching rates of copper and cobalt are 90.05% and 89.63%, respectively, and the leaching rates of iron, lead and antimony are 7.52%, 8.93% and 6.14%. The replacement rate of copper in the electrical replacement process was 93.68%, the purity of the sponge copper was 94.14%, and the iron, lead, antimony, and cobalt contents in the sponge copper were 0.26%, 0.72%, 0.34%, and 0.14%, respectively. Compared with Example 6, the leaching rate of copper and cobalt decreased, and the leaching rate of metal impurities such as iron, lead, and antimony increased, and the recovered metal and the impurity metal were not effectively separated, resulting in a relative increase in the content of the impurity metal in the subsequent sponge copper, and the grade of the sponge copper increased from 98.86 % fell to 94.14%. It shows that the low concentration of methanesulfonic acid in the leaching process will affect the selective leaching of metals.

Comparative Example 4

Compared with Example 6, the only difference is that the replacement process in step (2) sets the current density to 40 mA/cm ² , and other operations are the same.

The result is:

The replacement rate of copper in the electrical replacement process was 90.16%, and the purity of the sponge copper was 91.14%. Compared with Example 5, the replacement rate and purity of sponge copper decreased, and the content of impurity ions increased significantly, indicating that the current density was too high to replace the impurity metal, which competed with the replacement of copper.

Claims (16)

1. a method for recovering copper, cobalt from copper-cobalt slag, is characterized in that, comprises the following steps: Step (1): carry out selective oxidation leaching of copper cobalt slag and oxidant in a methanesulfonic acid solution system, followed by solid-liquid separation to obtain copper cobalt methanesulfonic acid leaching solution and metal impurity slag; in the methanesulfonic acid solution, The concentration of methanesulfonic acid is 80~150g/L; Step (2): subjecting the copper-cobalt methanesulfonic acid leaching solution to electro-replacement treatment to separate the sponge copper and the copper-removed cobalt solution; wherein, the current density in the electro-replacement process is 10-30 mA/cm ² . 2. the method for recovering copper and cobalt from copper-cobalt slag as claimed in claim 1, is characterized in that, described copper-cobalt slag contains copper, cobalt and metal impurity elements; Described metal impurity element is to contain iron , at least one of lead and antimony. 3. the method for recovering copper and cobalt from copper-cobalt slag as claimed in claim 1, is characterized in that, in described copper-cobalt slag, copper-containing 10%～30%, cobalt-containing 1%～10%, each The content of metal impurities is not higher than 5%. 4. the method for reclaiming copper, cobalt from copper-cobalt slag as claimed in claim 1, is characterized in that, in described methanesulfonic acid solution, the concentration of methanesulfonic acid is 80～120g/L. 5. the method for reclaiming copper, cobalt from copper-cobalt slag as claimed in claim 1, is characterized in that, the solid-liquid mass ratio of copper-cobalt slag and methanesulfonic acid solution is 1:4～8. 6. The method for recovering copper and cobalt from copper-cobalt slag as claimed in claim 1, wherein the oxidant is hydrogen peroxide. 7. The method for recovering copper and cobalt from copper-cobalt slag as claimed in claim 1, wherein the temperature of the selective oxidation leaching process is 30 to 90°C. 8. the method for recovering copper, cobalt from copper-cobalt slag as claimed in claim 7, is characterized in that, leaching time is 0.5～3h. 9. the method for reclaiming copper, cobalt from copper-cobalt slag as claimed in claim 1, is characterized in that, in step (2), adopts copper-cobalt methanesulfonic acid leaching solution as replacement stock solution; Taking metal plate as anode, inert electrode It is the cathode, which is immersed in the replacement stock solution and electrified for electrical replacement; The metal sheet is zinc and/or iron; The inert cathode is graphite, titanium mesh or stainless steel plate; The area ratio of cathode and anode plates is 1:1; The distance between the plates is 2 to 5 cm. 10. the method for reclaiming copper, cobalt from copper-cobalt slag as claimed in claim 1 or 9, is characterized in that, in step (2), the concentration of methanesulfonic acid in the control copper-cobalt methanesulfonic acid leaching solution is 20～80g /L. 11. the method for reclaiming copper, cobalt from copper-cobalt slag as claimed in claim 10, is characterized in that, in step (2), the concentration of methanesulfonic acid in the control copper-cobalt methanesulfonic acid leachate is 30～70g/L . 12. The method for recovering copper and cobalt from copper-cobalt slag as claimed in claim 1 or 9, wherein in step (2), the pH of the electro-displacement starting solution is 0.2 to 3. 13. The method for recovering copper and cobalt from copper-cobalt slag according to claim 1 or 9, characterized in that the current density in the electric displacement process is 10-20 mA/cm ² . 14 . The method for recovering copper and cobalt from copper-cobalt slag according to claim 13 , wherein the current density in the electric displacement process is 15-20 mA/cm ² . 15. The method for recovering copper and cobalt from copper-cobalt slag as claimed in claim 1 or 9, characterized in that the temperature of the electric displacement process is 30-80°C. 16 . The method for recovering copper and cobalt from copper-cobalt slag as claimed in claim 1 , wherein the obtained copper-removing cobalt solution is subjected to a precipitation reaction with oxalic acid, followed by calcination to obtain Co ₃ O ₄ . 17 .

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