Method and system for extracting copper and cobalt from copper-cobalt slag

Abstract

The invention discloses a method and system for extracting copper and cobalt from copper-cobalt slag. The method comprises: adding sulfide ore containing copper and cobalt to the copper-cobalt slag, adding acid, firstly performing one-stage leaching, and then performing two-stage leaching to obtain a leaching solution containing cobalt and copper. By adding sulfide ore containing copper and cobalt to the copper-cobalt slag and then performing two-stage leaching, the copper-cobalt leaching rate can be guaranteed, the acid consumption can be reduced, the processing flow can be simplified, and the occurrence of safety problems can be avoided.

Description

Technical Field

[0001] The invention relates to the technical field of copper-cobalt ore smelting slag treatment, and in particular to a method and system for extracting copper and cobalt from copper-cobalt slag. Background Art

[0002] The slag obtained from the pyrometallurgical smelting of copper-cobalt ore mainly consists of Fe, Si, Ca, Al, Co and Cu. Currently, there is a lack of some low-cost and relatively mature treatment methods.

[0003] After studying and analyzing the treatment process of copper-cobalt ore pyrometallurgical slag, it was found that the direct acid leaching treatment method has low Co and Cu leaching rates, high acid consumption, and a large amount of neutralizer required for slurry neutralization after acid leaching, which is costly. The use of pressurized oxygen leaching alone also has the problem of high acid consumption. In addition, during the leaching process, some silicon enters the leachate, making filtering difficult. In addition, the treatment process of reduction grinding and then acid leaching is relatively complicated, with high reagent costs, and the replacement process will also introduce new elements.

[0004] Therefore, it is urgent to develop a new processing process for extracting copper and cobalt from copper-cobalt slag. Summary of the invention

[0005] According to one embodiment of the present invention, the purpose is to provide a new method and system for extracting copper and cobalt from copper-cobalt slag to solve at least one of the above problems. The above purpose can be achieved by the following technical solutions:

[0006] According to one aspect of the present invention, the present invention provides a method for extracting copper and cobalt from copper-cobalt slag, comprising: adding sulfide ore containing copper and cobalt to the copper-cobalt slag, adding acid, first performing a first-stage leaching, and then performing a second-stage leaching after the first-stage leaching to obtain a leaching solution containing cobalt and copper; wherein, during the first-stage leaching, after adding acid, first react at 60-90°C for 0.2-3h, then add water and react for 0.2-3h; and the second-stage leaching adopts pressurized oxygen leaching.

[0007] Preferably, the end point acidity of the pressurized oxygen leaching is 10 g / t to 60 g / t.

[0008] Preferably, the amount of water added is such that the weight ratio of the total weight of water and sulfuric acid to the weight of the mixed material of copper-cobalt slag and copper and cobalt sulfide ores is 2.5 to 8.0:1.

[0009] Preferably, the mass concentration of the acid is 30% to 60%.

[0010] Preferably, the acid is sulfuric acid.

[0011] Preferably, during pressurized oxygen leaching, the leaching pressure is 0.6 MPa to 3.2 MPa, the oxygen partial pressure is 0 to 0.5 MPa, the leaching temperature is 160° C. to 230° C., and the leaching time is 0.3 h to 3 h.

[0012] Preferably, the method further comprises: extracting and electrolytically depositing the leaching solution containing cobalt and copper to obtain electrolytic copper; adding an oxidant and a neutralizing agent to the stripping solution obtained by extraction to remove iron, aluminum and manganese to obtain a de-impurity solution; precipitating copper in the de-impurity solution to obtain a copper precipitation solution and copper slag; precipitating cobalt in the copper precipitation solution to obtain a cobalt product and a cobalt precipitation solution; and returning the copper slag and the cobalt precipitation solution to the first stage of leaching.

[0013] Preferably, the pH is controlled at 3.5-4.2 when removing iron, aluminum and manganese; the pH is controlled at 4.4-6.5 when precipitating copper; and the pH is controlled at 7.5-8.5 when precipitating cobalt.

[0014] Preferably, when removing iron, aluminum and manganese, a combination of oxygen and a sulfur-containing reagent is used to oxidize the iron and manganese elements.

[0015] Preferably, the oxygen can be provided by one or more of pure oxygen, air or oxygen-enriched air. The sulfur-containing reagent is selected from one or more of sodium sulfite, sodium bisulfite, calcium thiosulfate, calcium sulfite, sodium pyrosulfite and SO2.

[0016] Preferably, the amount of sulfur-containing reagent added is converted into the amount of sulfur element substance, which is 1 to 10% of the molar amount of oxygen added.

[0017] According to another aspect of the present invention, the present invention provides a system for extracting copper and cobalt from copper-cobalt slag, comprising: a one-stage leaching unit and a pressure autoclave, wherein the one-stage leaching unit is used for one-stage leaching, has a material addition port, an acid addition port and a water replenishment port, and is also provided with a first temperature control component for controlling the temperature, wherein the material addition port is used for adding the copper-cobalt slag and the sulfide ore containing copper and cobalt after the ingredients are added, and the water replenishment port is used for replenishing water after the acid addition reaction, and the one-stage leaching unit also has a one-stage leachate outlet; the pressure autoclave is connected to the one-stage leachate outlet, and has an oxygen addition port, a pressure control component and a second temperature control component, which is used for pressurizing the oxygen leaching of the one-stage leachate to obtain a leachate containing cobalt and copper.

[0018] Preferably, the autoclave has an acidity detection unit for detecting the endpoint acidity of the pressurized oxygen immersion.

[0019] Preferably, the system further comprises: a composition determination unit for determining the composition of the copper-cobalt slag and the sulfide ore containing copper and cobalt to determine the proportion of addition.

[0020] Preferably, the system further comprises: a weighing unit for weighing the weight of the copper-cobalt slag, the sulfide ore containing copper and cobalt, the sulfuric acid, and the water replenished from the water replenishment port.

[0021] Preferably, the system further comprises: an extraction unit for extracting a leachate containing cobalt and copper to obtain an extracted organic phase and a raffinate, and stripping the extracted organic phase; an electrolytic copper unit for electrolytically depositing the stripped solution as an electro-rich solution to obtain electrolytic copper; a cobalt product preparation unit for sequentially removing iron, aluminum and manganese from the raffinate, and precipitating copper and cobalt to obtain a cobalt product; and the cobalt product preparation unit is connected to a first-stage leaching unit, and is used to return the copper slag obtained by copper precipitation and the cobalt precipitation solution obtained by cobalt precipitation to the first-stage leaching unit.

[0022] Beneficial effects: According to one embodiment of the present invention, two-stage leaching is adopted, and the leaching rate of silicon is reduced after the first-stage leaching treatment, the metal phase entering the second-stage leaching is reduced, the initial acidity of the second-stage leaching is reduced, and the safety problem caused by the generation of hydrogen during the pressurized leaching process is avoided; based on the first-stage acid leaching treatment, the second-stage oxygen pressure leaching is carried out to ensure the leaching rate of copper and cobalt by oxygen pressure leaching; in addition, sulfide ore is pre-added to the copper-cobalt slag, and sulfur is provided by the sulfide ore, which ensures the copper-cobalt leaching environment and provides the required heat, thereby reducing the acid consumption to a certain extent. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic flow chart of a method for extracting copper and cobalt from copper-cobalt slag in one embodiment of the present invention. DETAILED DESCRIPTION

[0024] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] The inventors of the present application have conducted a composition analysis of the copper-cobalt slag obtained from the pyrometallurgical smelting of copper-cobalt ore, and have continuously studied the current treatment methods, and found that: 1) the copper-cobalt slag obtained from the pyrometallurgical smelting of copper-cobalt ore has a low sulfur content, a dense structure, and a certain metal phase. Therefore, it is difficult to leach copper and cobalt even if a large amount of acid is used in atmospheric pressure leaching; compared with atmospheric pressure leaching, oxygen pressure leaching is an effective method for treating the copper-cobalt slag, but more acid also needs to be added to the system to ensure the leaching of cobalt and copper, especially when the sulfur content in the copper-cobalt slag is low, more sulfuric acid needs to be used and more neutralizers need to be used in the leaching slurry; the present application uses copper- and cobalt-containing sulfide ores as sulfur sources in oxygen pressure leaching of copper-cobalt slag, and pre-adds them to the copper-cobalt slag, so that the valuable elements leached from the two can enter the leaching solution at the same time, thereby reducing acid consumption while ensuring the leaching rate of copper and cobalt. 2) In addition to Co and Cu, copper-cobalt slag also contains other metal phases, such as Fe, Si, Ca, and Al, of which the silicon content is generally 15-20%. During the leaching process, part of the silicon will enter the leachate, resulting in difficulty in filtering. Based on this, the inventors of the present application further improved and optimized, and provided a new method, by pre-adding sulfide ore into the copper-cobalt slag to provide a sulfur source to reduce acid consumption, and adopting two-stage leaching based on the materials after addition, first performing one-stage leaching and then performing two-stage leaching, and in the first-stage leaching process, the amount of silicon entering the solution is reduced by adding acid and heating to react first + replenishing water and then reacting, and the metal phase entering the second-stage leaching is reduced, and the initial acidity of the second-stage leaching is reduced, while avoiding the safety problems caused by the generation of hydrogen during the pressurized leaching process, and adopting oxygen-pressurized two-stage leaching after the first-stage leaching to ensure the oxygen pressure leaching copper and cobalt leaching rate.

[0026] Figure 1 The method for extracting copper and cobalt from copper-cobalt slag provided in the embodiment of the present application is schematically shown, such as Figure 1 As shown, the following steps are included:

[0027] Step S10, adding sulfide ore containing copper and cobalt into the copper-cobalt slag, adding acid, and first performing a leaching step.

[0028] By adding copper- and cobalt-containing sulfide ores, such as cobalt concentrate, into the copper-cobalt slag as a sulfur source in the oxygen pressure leaching of the copper-cobalt slag, the required sulfur element is supplemented, the leaching environment of Co and Cu and the required heat are guaranteed, and the acid consumption is reduced. Furthermore, after adding copper- and cobalt-containing sulfide ores into the copper-cobalt slag with a sulfur content of ≤0.8%, the sulfur content in the mixed material is ≥4%, which can provide a better leaching environment and required heat for Co and Cu. At the same time, the valuable elements leached from the copper-cobalt slag and the copper- and cobalt-containing sulfide ores can enter the leaching solution at the same time, while ensuring the leaching rate of copper and cobalt, the acid consumption can also be reduced.

[0029] In addition, during the first stage of leaching, the leaching method of "heating and acid reaction + water supplement and then reaction" is adopted. Specifically, acid is added and mixed with the mixed material, and the reaction is first carried out for 0.2 to 3 hours at a temperature of 60 to 90°C; then water is supplemented and the reaction is continued for 0.2 to 3 hours. For example, the heating temperature can be 60°C, 70°C, 80°C, 90°C, etc., and the reaction time can be 0.5h, 1h, 2h, etc. By adding acid and heating to react for a certain time and then supplementing water to react for a certain time, silicon can be converted and the proportion of silicon entering the solution during the entire leaching process can be reduced.

[0030] Preferably, the mass concentration of the acid can be 30% to 60%, and silicon can be converted more efficiently under heating and high acid conditions. The acid can be sulfuric acid or the like.

[0031] In addition, the amount of water added after the heating and acidification reaction is controlled to be (water + sulfuric acid): mixed material weight ratio = 2.5 to 8.0: 1. By controlling the amount of water added, the fluidity of the slurry is adjusted, and a balance is found between the fluidity of the slurry and the amount of raw material processed (the higher the weight ratio, the less raw ore is processed by the same volume of autoclave), which is more conducive to the subsequent pressurized oxygen leaching to ensure the leaching rate of copper and cobalt. In addition, the amount of sulfuric acid used can be determined according to the acid-ore ratio during the first stage of leaching. Preferably, the amount of sulfuric acid used is: 100 to 1100 kg / t ore.

[0032] Through the method of one-stage leaching and adding acid to heat to react first and then add water and react again, on the one hand, the amount of silicon in the solution after the first stage of leaching is reduced, and the silicon content in the solution after the first stage of leaching is ≤300mg / L; on the other hand, through the first stage of leaching, part of the metal phase will react with the acid, reducing the metal phase in the solution after the first stage of leaching, that is, the metal phase entering the second stage of leaching is reduced; on the other hand, part of the acid is reacted during the first stage of leaching, thus reducing the initial acidity of the second stage of leaching. In addition, after the first stage of leaching, part of the metal phase is consumed by reaction and the acid concentration is also reduced, thereby avoiding the safety problems caused by the generation of hydrogen during the pressurized leaching process.

[0033] Step S20, after the first leaching, a second leaching is performed, i.e., pressurized oxygen leaching, to obtain a leachate and a leaching residue. Further, the leachate is extracted and electrolytically deposited to obtain electrolytic copper, and the stripping solution is impurity-removed and precipitated to obtain a cobalt product.

[0034] In addition, preferably, when pressurized oxygen leaching is performed, the leaching pressure is 0.6MPa to 3.2MPa (total pressure), the oxygen partial pressure is 0 to 0.5MPa, the leaching temperature is 160°C to 230°C, and the leaching time is 0.3h to 3h, for example, 0.5h, 1h, 2.5h, etc. For the solution after a stage of leaching, by adopting the above conditions for pressurized oxygen leaching, the Co leaching rate is higher than 94%, and the Cu leaching rate is higher than 91%; and the Fe leaching rate is not higher than 10%, thereby reducing the difficulty of separation of subsequent solutions. Among them, the terminal acidity of pressurized oxygen leaching is 10g / t to 60g / t, and the final acid is used to take into account both acid consumption and leaching effects such as cobalt and copper leaching rates.

[0035] During the extraction, a copper extractant is added to extract the leachate, and the extract (organic phase) is stripped. The stripping solution (i.e., electro-rich solution) after extraction and stripping is electrolytically deposited to obtain electrolytic copper; the raffinate after extraction is added with an oxidant and a neutralizer to remove iron, aluminum, and manganese to obtain a de-impurity solution; the de-impurity solution is used to precipitate copper to obtain a copper precipitation solution and copper slag, the copper slag is returned to the first leaching, the copper precipitation solution is added with a neutralizer to precipitate cobalt to directly obtain a cobalt product, and the cobalt precipitation solution is returned to the first leaching.

[0036] Among them, when removing iron, aluminum and manganese, a combination of oxygen and sulfur-containing reagents is used to oxidize iron and manganese elements. Oxygen can be provided by pure oxygen, air or oxygen-enriched air. The sulfur-containing reagent is selected from one or more of sodium sulfite, sodium bisulfite, calcium thiosulfate, calcium sulfite, sodium pyrosulfite, and SO2. The amount of sulfur-containing reagent added is converted into the amount of sulfur element substance, which is 1-10% of the molar amount of oxygen added. The oxidation speed of using this oxidant combination is fast, and iron and manganese ions can be oxidized at the same time. A neutralizer is added to control the pH to 3.5-4.2, and impurities are removed to improve the impurity removal rate. Since the iron leaching rate is low after the second stage leaching, Fe impurities are more convenient to remove, which further improves the impurity removal rate, thereby improving the purity of the cobalt product. When copper is precipitated, the pH is controlled to be 4.4-6.5 to improve the copper precipitation rate. When cobalt is precipitated, MgO or sodium carbonate is used as a neutralizer to control the pH to 7.5-8.5 to improve the cobalt precipitation rate.

[0037] By extracting and electrowinning the leaching solution under the above conditions, the purity of the electrowinning copper is improved. By removing impurities, copper precipitation and cobalt precipitation of the stripping solution under the above conditions, the impurity content in the cobalt product, such as Fe, Al, Mn, Cu, etc., is reduced, and the purity of the cobalt product is improved.

[0038] The present application is described in more detail below with reference to specific embodiments:

[0039] Example 1

[0040] In this embodiment, cobalt concentrate is added to the copper-cobalt slag. The compositions of the copper-cobalt slag and the cobalt concentrate are shown in Table 1:

[0041] Table 1 Composition of copper-cobalt slag and cobalt concentrate

[0042] element Co Cu Fe Al Ca Mg Si S Copper-cobalt slag content,% 0.97 1.85 20.30 3.21 8.36 1.73 17.66 0.61 Cobalt Concentrate content,% 2.12 3.87 12.35 5.32 4.39 2.50 20.35 14.27

[0043] Extract copper and cobalt (leaching solution) from the copper-cobalt slag: weigh 70g of copper-cobalt slag and 30g of cobalt concentrate, add 30g of sulfuric acid with a mass concentration of 40%, perform a leaching, first react at 85°C for 2h, then add 570g of water and react for another 2h; then transfer to a pressure autoclave, leaching temperature 180°C, corresponding autoclave pressure 1.5Mpa (total pressure), oxygen partial pressure 0.5MPa, leaching time 2h, end point acidity 36g / L, filter, and obtain leachate and filter residue. Among them, the Co leaching rate is 95%, the Cu leaching rate is 92%, the Fe leaching rate is 10%, and the Si concentration in the leachate is only 150mg / L.

[0044] Copper-cobalt separation: The leachate is subjected to extraction-electrodeposition method to obtain electrolytic copper, and the raffinate is subjected to impurity removal-copper precipitation-cobalt precipitation treatment to obtain precipitated cobalt hydroxide. Among them, the raffinate obtained has the following components: Cu 0.2g / L, Co 2.4g / L, Mn 3.0g / L, Fe 4.2g / L. SO2 / O2 is used as an oxidant (the amount of sulfur element substance is 2% of the molar amount of oxygen added), and CaCO3 is used as a neutralizer to remove iron, aluminum, and manganese. The pH is 4.0 and the reaction is carried out for 3 hours. After the reaction, the concentrations of Fe, Al, and Mn in the solution are reduced to 8mg / L, 88mg / L, and 100mg / L, and Co is 2.0g / L. The impurity removal filtrate is adjusted to pH 6.0 with calcium carbonate to precipitate copper, and the Cu concentration in the solution is reduced to 5mg / L. The copper slag is returned to the first leaching. The pH of the solution after copper precipitation is adjusted to 8.0 to precipitate cobalt, and the cobalt concentration is reduced to 0.02 g / L. The cobalt precipitation solution is returned to the first leaching stage, and the precipitate is cobalt hydroxide.

[0045] The description of the present invention is given for the purpose of illustration and description, and is not intended to be exhaustive or to limit the invention to the disclosed form. Many modifications and variations will be apparent to those of ordinary skill in the art. The embodiments are selected and described in order to better illustrate the principles and practical applications of the present invention and to enable those of ordinary skill in the art to understand the present invention and thereby design various embodiments with various modifications suitable for particular uses.

Claims

1. A method for extracting copper and cobalt from copper-cobalt slag, characterized in that: include: Adding sulfide ore containing copper and cobalt to the copper-cobalt slag to make the sulfur content in the mixture ≥4%, adding acid, firstly performing a first-stage leaching, and then performing a second-stage leaching to obtain a leaching solution containing cobalt and copper; In the first stage of leaching, sulfuric acid with a mass concentration of 30% to 60% is added and reacted at 60 to 90°C for 0.2 to 3 hours, and then water is added and reacted for 0.2 to 3 hours. The amount of water added is such that the weight ratio of the total weight of water and sulfuric acid to the weight ratio of the mixed materials of copper-cobalt slag and copper and cobalt sulfide ore is 2.5 to 8.0:1; The second stage leaching adopts pressurized oxygen leaching, the end point acidity of pressurized oxygen leaching is 10g / l~60g / l, the leaching pressure is 0.6MPa~3.2MPa, the oxygen partial pressure is 0~0.5MPa, the leaching temperature is 160℃~230℃, and the leaching time is 0.3h~3h; Extracting and electrowinning the leaching solution containing cobalt and copper to obtain electrowinning copper; The stripping solution obtained by extraction is added with an oxidant and a neutralizing agent to remove iron, aluminum and manganese to obtain a de-impurity solution, copper is precipitated from the de-impurity solution to obtain a copper precipitation solution and copper slag, and cobalt is precipitated from the copper precipitation solution to obtain a cobalt product and a cobalt precipitation solution; the copper slag and the cobalt precipitation solution are returned to the first stage for leaching; Wherein, the oxidant is a combination of oxygen and a sulfur-containing reagent; a neutralizer is added to control the pH to be 3.5-4.

2.

2. The method for extracting copper and cobalt from copper-cobalt slag according to claim 1, characterized in that: When copper is deposited, the pH is controlled at 4.4-6.5; when cobalt is deposited, the pH is controlled at 7.5-8.

5.

3. The method for extracting copper and cobalt from copper-cobalt slag according to claim 1 or 2, characterized in that: When removing iron, aluminum and manganese, The oxygen is provided by pure oxygen or air; the sulfur-containing reagent is selected from one or more of sodium sulfite, sodium bisulfite, calcium thiosulfate, calcium sulfite, sodium pyrosulfite, and SO2; And / or, the amount of the sulfur-containing reagent added is converted into an amount of sulfur element substance which is 1 to 10% of the molar amount of oxygen added.

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