Recovery method for cobalt intermediate

Abstract

A recovery method for a cobalt intermediate. The cobalt intermediate is firstly pulped, and is sequentially subjected to neutral leaching, reduction acid leaching and high-acid leaching, wherein trivalent cobalt is reduced into divalent cobalt, while ferrous iron is oxidized into ferric iron during the neutral leaching process, and most cobalt can be leached by means of neutral leaching, while impurities, such as copper and aluminum, are co-precipitated together with ferric hydroxide; high-valence cobalt in neutral leaching residues is reduced into divalent cobalt ions by means of reduction acid leaching, thereby achieving the efficient leaching of neutral residues; and the acid leaching residues obtained after reduction acid leaching are subjected to high-acid leaching to recover cobalt metal in the acid leaching residues to the maximum extent, thereby improving the recovery rate of cobalt.

Description

A method for recovering cobalt intermediates Technical Field

[0001] The present disclosure belongs to the technical field of hydrometallurgy, and in particular relates to a method for recovering a cobalt intermediate. Background Art

[0002] Non-ferrous metals are fundamental to the development of the national economy. With rapid economic growth, demand for non-ferrous metals is increasing, and metallurgical technologies for their extraction must also continue to innovate alongside scientific and technological advancements. Hydrometallurgy is a key technical approach in the metallurgical field. It involves transferring ore, concentrated ore, or other raw materials through leaching agents into a liquid phase, thereby achieving metal separation, enrichment, and extraction. Generally speaking, hydrometallurgy involves processes such as leaching, metal enrichment, and solution purification.

[0003] Recovering cobalt and other valuable metals from cobalt solution has good economic value. At the same time, it is also necessary to effectively remove iron from the cobalt solution. The most widely used iron removal methods are as follows:

[0004] (1) Chemical precipitation method

[0005] The chemical precipitation method converts the iron ions in the cobalt leachate into precipitates through chemical reactions and then performs solid-liquid separation to achieve the purpose of iron removal. This method has the advantages of simple operation, low cost, and good iron removal effect, but it also has disadvantages such as large slag volume and difficulty in filtration.

[0006] (2) Oxidation precipitation method

[0007] The oxidation precipitation method primarily uses oxidants such as oxygen and hydrogen peroxide. Through redox reactions, iron ions are oxidized to ferric ions. By controlling the concentration of the iron ions, the iron ions are precipitated. While the goethite method offers advantages such as rapid iron removal and high efficiency, it also has drawbacks such as demanding reaction conditions, making them difficult to achieve in actual production.

[0008] Existing methods for removing iron from cobalt solutions generally have the following problems: large slag volume and high cost. In addition, the existing cobalt solution recovery methods need to effectively improve the cobalt recovery rate.

[0009] In view of this, the present disclosure is proposed.

[0010] Summary of the Invention

[0011] The present disclosure aims to provide a method for recovering a cobalt intermediate, which aims to significantly improve the recovery rate of cobalt.

[0012] In order to achieve the above-mentioned purpose of the present disclosure, the following technical solutions can be adopted:

[0013] The solution provided by the present disclosure includes a method for recovering a cobalt intermediate, comprising: mixing the cobalt intermediate with sulfuric acid, performing neutral leaching under oxidizing conditions, controlling the pH value of the leaching to be 5.0-5.4, and obtaining a neutral leaching residue and a post-leaching liquid;

[0014] The neutral leaching residue is subjected to reduction acid leaching to obtain acid leaching residue and acid leaching liquid;

[0015] The acid leaching residue is subjected to high acid leaching, and the pH value is controlled to be less than 0.5 to obtain a high acid leaching solution;

[0016] The high acid leachate is returned to the neutral leaching stage.

[0017] In some embodiments of the present disclosure, the neutral leaching process includes: mixing a cobalt intermediate with water to obtain a cobalt intermediate slurry, wherein the mass fraction of the cobalt intermediate in the cobalt intermediate slurry is 13%-15%, mixing the cobalt intermediate slurry with sulfuric acid and an oxidant for reaction, controlling the leaching temperature to 50°C-70°C, and the reaction time to 1.5h-1.6h.

[0018] In some embodiments of the present disclosure, when the mass fraction of iron in the cobalt intermediate is less than 0.5%, ferrous sulfate is supplemented to participate in the neutral leaching reaction, and the mass ratio of the amount of ferrous sulfate supplemented to the amount of cobalt metal in the cobalt intermediate is (4-6):100.

[0019] In some embodiments of the present disclosure, during the neutral leaching process, multiple reactors are connected in series, cobalt intermediate slurry, sulfuric acid and oxidant are added to the first reactor, cobalt intermediate slurry is added to the middle reactor, the pH value of the leaching is controlled to be 5.0-5.4, and the residence time in each reactor is 1.5h-1.6h;

[0020] When the mass fraction of iron in the cobalt intermediate is less than 0.5%, ferrous sulfate is further added to the first reactor.

[0021] In some embodiments of the present disclosure, the oxidant is selected from at least one of oxygen-containing gas and hydrogen peroxide.

[0022] In some embodiments of the present disclosure, the oxygen-containing gas is selected from at least one of air and oxygen-rich gas, and the volume fraction of oxygen in the oxygen-rich gas is 21%-90%.

[0023] In some embodiments of the present disclosure, the reduction acid leaching process includes: mixing the neutral leaching residue with water to form a slurry, and then mixing it with sulfuric acid and a reducing agent, the leaching temperature is 60° C.-80° C., and the leaching time is greater than 2 hours.

[0024] In some embodiments of the present disclosure, the leaching temperature of the reduction acid leaching is 65° C.-75° C., the leaching time is 3 h-4 h, and the leaching pH value is 1.5-2.0.

[0025] In some embodiments of the present disclosure, the reducing agent is selected from at least one of sulfur dioxide, ammonium metabisulfite, and hydrogen peroxide.

[0026] In some embodiments of the present disclosure, the reducing agent is sulfur dioxide.

[0027] In some embodiments of the present disclosure, the amount of sulfur dioxide is calculated according to the volume of the slurry, and the amount of sulfur dioxide is 0.1-1Nm 3 / m 3 .

[0028] In some embodiments of the present disclosure, sulfur dioxide produced in the acid production system is dried and compressed and then introduced into the reduction acid leaching reactor.

[0029] In some embodiments of the present disclosure, the mass ratio of neutral leaching residue to water is 1:(3-5).

[0030] In some embodiments of the present disclosure, the high acid leaching process includes: mixing the acid leaching residue with hydrogen peroxide and sulfuric acid, controlling the reaction temperature to 85° C.-95° C., the reaction pH to 0.25-0.45, and the leaching time to 4 h-5 h.

[0031] In some embodiments of the present disclosure, the process further includes: mixing the acid leaching liquid generated in the reduction acid leaching process with iron powder to perform a copper removal reaction to obtain a copper-removed liquid, and the copper-removed liquid enters the iron removal process.

[0032] In some embodiments of the present disclosure, the concentration of copper ions in the copper-removed solution is adjusted to be 50 mg / L-200 mg / L by adjusting the amount of iron powder used.

[0033] In some embodiments of the present disclosure, the iron removal process includes: mixing the copper-removed liquid with an oxygen-containing gas, a neutralizing agent, and a nucleating agent to react, controlling the reaction pH to be 3.0-3.5, and maintaining the Fe content in the system at 1.5. 3+ The concentration is less than 1g / L.

[0034] In some embodiments of the present disclosure, in the iron removal process, the reaction temperature is controlled to be 80° C.-90° C., and the reaction time is 2 h-3 h.

[0035] In some embodiments of the present disclosure, the oxygen-containing gas is selected from at least one of air and oxygen-rich gas, and the volume fraction of oxygen in the oxygen-rich gas is 21%-90%.

[0036] In some embodiments of the present disclosure, the flow rate of the oxygen-containing gas is regulated according to the volume of the solution, and the flow rate of the oxygen-containing gas is 0.1 NM 3 / m 3 -1.0NM 3 / m 3 .

[0037] In some embodiments of the present disclosure, the neutralizing agent is selected from at least one of cobalt carbonate and a cobalt intermediate.

[0038] In some embodiments of the present disclosure, the nucleating agent is calcium carbonate.

[0039] In some embodiments of the present disclosure, the concentration of the generated calcium sulfate crystals is 1 g / m 3 -100g / m 3 .

[0040] In some embodiments of the present disclosure, the iron removal process is a continuous iron removal process, comprising a first reaction tank, a second reaction tank, a third reaction tank and a fourth reaction tank connected in series, wherein the copper removal liquid, an oxygen-containing gas and a neutralizing agent are added to the first reaction tank, the copper removal liquid, the neutralizing agent and the nucleating agent are added to the second reaction tank, the oxygen-containing gas is added to the third reaction tank, and the material output from the fourth reaction tank is subjected to solid-liquid separation, and the Fe content in the obtained liquid material is reduced. 3+ When the concentration is greater than 1 g / L, it returns to the first reaction tank.

[0041] In some embodiments of the present disclosure, the residence time of the first reaction tank, the second reaction tank, the third reaction tank, and the fourth reaction tank is 1.5 h to 2.5 h.

[0042] The cobalt intermediate is subjected to neutral leaching, reductive acid leaching and high-acid leaching in sequence. During the neutral leaching process, divalent iron is oxidized to trivalent iron and trivalent cobalt is reduced to divalent cobalt. Most of the cobalt can be leached out through neutral leaching, and impurities such as copper and aluminum are co-precipitated with ferric hydroxide. Reductive acid leaching is used to reduce the residual high-valent cobalt in the neutral leaching residue to divalent cobalt ions, thereby achieving efficient leaching of the neutral residue. The acid leaching residue obtained after the reductive acid leaching is subjected to high-acid leaching to maximize the recovery of cobalt metal in the acid leaching residue and improve the recovery rate of cobalt. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present disclosure and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without creative work.

[0044] FIG1 is a full flow chart of the multi-stage leaching and continuous iron removal crystallization process in cobalt intermediates;

[0045] FIG2 is a process diagram for neutral leaching of cobalt intermediates;

[0046] FIG3 is a diagram of a sulfur dioxide reduction acid leaching process;

[0047] Figure 4 is a diagram of the continuous iron removal crystallization process. DETAILED DESCRIPTION

[0048] The embodiments of the present disclosure will be described in detail below with reference to the examples. However, those skilled in the art will appreciate that the following examples are intended only to illustrate the present disclosure and should not be construed as limiting the scope of the present disclosure. Where specific conditions are not specified in the examples, the experiments were performed under conventional conditions or the conditions recommended by the manufacturer. Where the manufacturer of the reagents or instruments is not specified, all are commercially available conventional products.

[0049] The endpoints of the ranges and any values ​​disclosed in this disclosure are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoints of each range, the endpoints of each range and individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be considered to be specifically disclosed herein.

[0050] Preparation process of cobalt intermediates: The raw material is copper-cobalt ore, which is leached with sulfuric acid to obtain a leachate containing copper and cobalt. The leachate is then extracted with an extractant to extract copper. After copper removal, the residual liquid is deironed to obtain a deironed liquid. Activated magnesium oxide is then used to adjust the pH value to precipitate cobalt, obtaining a cobalt intermediate with crude cobalt hydroxide (Co(OH)2) as the main component. Other impurities contained in it include Ni, Mg, Mn, a small amount of Fe, Cu, Al, etc.

[0051] The present disclosure provides a method for recovering a cobalt intermediate, as shown in FIG1 , comprising the following steps:

[0052] S1, neutral leaching

[0053] The cobalt intermediate is mixed with sulfuric acid and subjected to neutral leaching under oxidizing conditions. The pH of the leaching is controlled at 5.0-5.4 to produce a neutral leaching residue and a post-leaching solution. During this process, the ferrous ions are oxidized while the trivalent cobalt ions are reduced to divalent cobalt (the principle is shown in the chemical equation), achieving the goal of leaching most of the cobalt. At the same time, by regulating the hydrolysis process of the ferric ions, the trivalent ferrous ions are hydrolyzed and precipitated to form a neutral leaching residue. Impurities such as copper and aluminum are enriched in the neutral leaching residue through neutralization, hydrolysis, and co-precipitation.

[0054] 6Fe 2+ +3 / 2O2+6H + ==6Fe 3+ +3H2O;

[0055] 3Fe 2+ +2Co3+ = =2Co 2+ +3Fe 3+ ;

[0056] Specifically, the pH value of the leaching can be 5.0, 5.1, 5.2, 5.3, 5.4, etc., and the pH value can be adjusted to meet the requirements by adjusting the amount of sulfuric acid or cobalt intermediate slurry.

[0057] In some embodiments of the present disclosure, the neutral leaching process includes: the neutral leaching process includes: mixing a cobalt intermediate with water to obtain a cobalt intermediate slurry, wherein the mass fraction of the cobalt intermediate in the cobalt intermediate slurry is 13%-15%, mixing the cobalt intermediate slurry with sulfuric acid and an oxidant for reaction, controlling the leaching temperature to be 50°C-70°C, and the reaction time to be 1.5h-1.6h. Specifically, the mass fraction of the cobalt intermediate in the cobalt intermediate slurry can be 13%, 14%, 15%, etc., the leaching temperature can be 50°C, 55°C, 60°C, 65°C, 70°C, etc., and the reaction time can be 1.50h, 1.55h, 1.60h, etc.

[0058] Furthermore, the oxidant is selected from at least one of an oxygen-containing gas and hydrogen peroxide, and may be any one or more of the above. The oxygen-containing gas is selected from at least one of air and an oxygen-enriched gas, and may be a mixture of any one or two of the above. Specifically, the oxygen-enriched gas has an oxygen volume fraction of 21% to 90%. The amount of the oxidant used is not limited, as long as it can fully promote the reaction.

[0059] In some embodiments of the present disclosure, when the mass fraction of iron in the cobalt intermediate is less than 0.5%, ferrous sulfate is supplemented to participate in the neutral leaching reaction. By controlling the amount of ferrous sulfate supplemented, the mass ratio of the amount of ferrous sulfate supplemented to the amount of cobalt metal in the cobalt intermediate is (4-6):100, such as 4:100, 5:100, 6:100, etc. When the content of divalent iron ions in the cobalt intermediate is low, an appropriate amount of ferrous sulfate is supplemented to participate in the reaction.

[0060] In some embodiments of the present disclosure, as shown in FIG2 , during the neutral leaching process, multiple reactors are connected in series, cobalt intermediate slurry, sulfuric acid, and an oxidant are added to the first reactor, and cobalt intermediate slurry is added to the middle reactor. The pH value of the leaching is controlled to be 5.0-5.4, and the residence time in each reactor is 1.5 h-1.6 h. When the mass fraction of iron in the cobalt intermediate is less than 0.5%, ferrous sulfate is added to the first reactor.

[0061] Specifically, the leaching device for neutral leaching can have 7 leaching tanks (such as tank A, tank B, tank C, tank D, tank E, tank F, and tank G in Figure 2). The first leaching tank can be called a neutral leaching oxidation tank, and the other leaching tanks are called neutral leaching tanks. After the last leaching tank outputs the material, pressure filtration separation is performed.

[0062] In other embodiments of the present disclosure, neutral leaching can also be performed in a single reactor, not limited to the apparatus shown in FIG. 2 .

[0063] S2, reduction acid leaching

[0064] The neutral leaching residue is subjected to reduction acid leaching to obtain acid leaching residue and acid leaching liquid. The iron in the neutral leaching residue can be reduced to divalent iron ions through reduction acid leaching, and the residual high-valent cobalt can be reduced to divalent cobalt ions, thereby achieving efficient leaching of the neutral slag.

[0065] In actual operation, the reduction acid leaching process includes: mixing the neutral leaching residue with water to form a slurry, with the mass ratio of the neutral leaching residue to water being 1:(3-5), then mixing it with sulfuric acid and a reducing agent, and leaching at a temperature of 60℃-80℃ for more than 2 hours to fully react and leach the cobalt. Specifically, the mass ratio of the neutral leaching residue to water can be 1:3, 1:4, 1:5, etc.; the leaching temperature can be 60℃, 65℃, 70℃, 75℃, 80℃, etc.; and the leaching time can be 2.5h, 3.0h, 4.0h, 5.0h, 6.0h, etc.

[0066] In a preferred embodiment of the present disclosure, the leaching temperature for reductive acid leaching is 65°C-75°C, the leaching time is 3-4 hours, and the leaching pH is 1.5-2.0. By optimizing the reductive acid leaching conditions, the cobalt leaching rate is increased. The leaching pH is adjusted by the amount of sulfuric acid added, and the leaching pH can be 1.5, 1.8, 2.0, etc.

[0067] In some embodiments of the present disclosure, the reducing agent is selected from at least one of sulfur dioxide, ammonium metabisulfite, and hydrogen peroxide, and may be any one or more of the above, preferably sulfur dioxide. Using sulfur dioxide as the reducing agent is readily available, avoids the introduction of other impurity ions, reduces the amount of sulfuric acid used, and resolves the problems of high production costs and low reduction efficiency caused by the introduction of other reducing agents.

[0068] Furthermore, sulfur dioxide can be supplied by an acid-generating system. As shown in Figure 3, the high-purity sulfur dioxide produced in the acid-generating system is dried and compressed before being delivered to the reductive acid leaching reactor. Specifically, the sulfur dioxide output from the acid-generating system enters a sulfur dioxide storage tank and then a drying tower for drying. The pipeline is directly connected to the reductive acid leaching process. The sulfur dioxide compressor is activated to maintain positive pressure in the pipeline, allowing high-purity, dry sulfur dioxide to continuously enter the reductive acid leaching reactor.

[0069] Furthermore, the amount of sulfur dioxide is calculated according to the volume of the slurry, and the amount of sulfur dioxide is 0.1-1Nm 3 / m 3 To allow the reduction reaction to proceed fully, the amount of sulfur dioxide used can be 0.1Nm 3 / m 3 , 0.5Nm 3 / m 3 , 1.0Nm 3 / m 3 wait.

[0070] S3, high acid leaching

[0071] The acid leaching residue is subjected to high acid leaching, and the pH value is controlled to be less than 0.5. The cobalt metal in the acid leaching residue can be further leached through high acid leaching to obtain a high acid leaching solution containing cobalt, and the high acid leaching solution is returned to the neutral leaching stage.

[0072] In some embodiments of the present disclosure, the high-acid leaching process includes: mixing the acid leaching residue with hydrogen peroxide and sulfuric acid, controlling the reaction temperature to 85°C-95°C, the reaction pH to 0.25-0.45, and the leaching time to 4-5 hours. The high-acid leaching conditions are further optimized to more fully leach cobalt. The theoretical amount of hydrogen peroxide is 1.3*(34*cobalt content in slag*8000kg) / (2*55.85)≈3200*cobalt content in slag (kg).

[0073] Specifically, the reaction temperature can be 85°C, 90°C, 95°C, etc., the reaction pH value can be 0.25, 0.30, 0.35, 0.40, 0.45, etc.; the leaching pH value can be 0.25, 0.30, 0.35, 0.40, 0.45, etc.; the leaching time can be 4.0h, 4.5h, 5.0h, etc.

[0074] S4, copper removal

[0075] The acid leaching solution produced during the reduction acid leaching process is mixed with iron powder to undergo a copper removal reaction to obtain a copper-removed solution, which then enters the iron removal process. The iron powder acts as a reducing agent to displace the copper ions in the acid leaching solution, resulting in sponge copper.

[0076] In some embodiments of the present disclosure, by adjusting the amount of iron powder, the concentration of copper ions in the copper removal solution is 50 mg / L-200 mg / L. A small amount of copper ions can be used as an iron catalyst. Most of the trivalent iron is reduced in the second stage reduction acid leaching process, and the iron exists in the solution in the form of ferrous ions, and the reaction occurs: SO2+2H2O+2Fe 3+ =2Fe 2+ +SO4 2-+4H + ;

[0077] During the copper removal stage, a small amount of trivalent iron is present and the following reaction occurs: 2Fe 3+ +Fe==3Fe 2+ ; Cu 2+ +Fe==Cu+Fe 2+ ;

[0078] Specifically, the concentration of copper ions in the copper removal solution can be controlled to be 50 mg / L, 100 mg / L, 150 mg / L, 200 mg / L, etc. Iron dosage (kg) = feed solution volume (m 3 )*Copper concentration of the second-stage leaching solution (g / l)*55.85 / 64*1.1, where 1.1 is the coefficient.

[0079] S5, iron removal

[0080] The iron removal process includes: mixing the copper-removed liquid with oxygen-containing gas, neutralizer and nucleating agent to react, controlling the reaction pH value to 3.0-3.5, and maintaining the Fe content in the system. 3+ The concentration is less than 1g / L. During the reaction, the oxygen-containing gas oxidizes the divalent iron ions in the solution and precipitates them. The nucleating agent can play the role of crystal seeds, greatly improving the growth rate of goethite and the filtration performance of iron slag (when Fe 3+ When the concentration is greater than 1g / L, Fe(OH)3 colloid is easily generated. The colloid has large particle size, is difficult to filter, and carries away more valuable metals). This solves the problems of large slag volume, poor filtration performance, and high energy consumption in the existing iron removal process, and can shorten the process flow of cobalt recovery in the overall process.

[0081] Specifically, the pH value of the reaction can be controlled to be 3.0, 3.1, 3.2, 3.3, 3.4, 3.5, etc., and the Fe 3+ The concentration can be 0.1g / L, 0.3g / L, 0.5g / L, 0.8g / L, 0.9g / L, etc.

[0082] In some embodiments of the present disclosure, the oxygen-containing gas is selected from at least one of air and oxygen-enriched gas, and can be a mixture of any one or two of the above, wherein the oxygen-enriched gas refers to an oxygen volume fraction of 21%-90%. Using air / oxygen-enriched air instead of hydrogen peroxide to oxidize ferrous ions reduces production costs. The flow rate of the oxygen-containing gas is regulated according to the volume of the solution, and the flow rate of the oxygen-containing gas is 0.1NM 3 / m 3 -1.0NM 3 / m 3 That is to say, 1m 3 The volume of the copper-removed liquid corresponds to a flow rate of 0.1 NM oxygen-containing gas.3 , 0.3NM 3 , 0.5NM 3 , 0.8NM 3 , 1.0NM 3 In actual operation, the flow rate of the oxygen-containing gas is adjusted according to the concentration of ferrous ions, the oxidation rate of ferrous ions is controlled, and the concentration of trivalent ions in the system is kept below 1 g / L.

[0083] In some embodiments of the present disclosure, the neutralizing agent is selected from at least one of cobalt carbonate and a cobalt intermediate, and may be a mixture of any one or both. The neutralizing agent, derived from nickel and cobalt, is used to adjust the leaching pH to meet the required pH. The iron precipitation process involves a continuous increase in acidity, and the use of a neutralizing agent also reduces sulfuric acid usage in the main process, lowering production costs.

[0084] In some embodiments of the present disclosure, the nucleating agent is calcium carbonate. By controlling the amount of the nucleating agent, the concentration of the generated calcium sulfate crystals is 1 g / m 3 -100g / m 3 (such as 1g / m 3 , 10g / m 3 , 30g / m 3 , 50g / m 3 , 80g / m 3 , 100g / m 3 etc.), using calcium sulfate crystals as crystal nuclei to accelerate the nucleation rate of goethite, and obtain iron slag with good filtration performance and high iron content.

[0085] Furthermore, in the iron removal process, the reaction temperature is controlled to be 80°C-90°C and the reaction time is 2h-3h. At this reaction temperature, iron can be further removed. Specifically, the reaction temperature can be 80°C, 85°C, 90°C, etc., and the reaction time can be 2.0h, 2.5h, 3.0h, etc.

[0086] In some embodiments of the present disclosure, the iron removal process can be continuous iron removal, as shown in FIG4 , comprising a first reaction tank, a second reaction tank, a third reaction tank, and a fourth reaction tank (i.e., a cobalt iron removal tank A, a cobalt iron removal tank B, a cobalt iron removal tank C, and a cobalt iron removal tank D in FIG4 ) connected in series, wherein the copper removal liquid, an oxygen-containing gas (such as air or oxygen), and a neutralizer are added to the first reaction tank, the copper removal liquid, the neutralizer, and the nucleating agent are added to the second reaction tank, the oxygen-containing gas is added to the third reaction tank, and the material output from the fourth reaction tank is subjected to solid-liquid separation, and the Fe content in the obtained liquid material is reduced. 3+ When the concentration is greater than 1g / L, it is returned to the first reaction tank, and the Fe 3+ If the concentration is less than 1g / l, it will not be returned. Each reaction tank is controlled at a pH value of 3.0-3.5, Fe 3+The concentration is less than 1g / L.

[0087] In some embodiments of the present disclosure, the residence time of the first reaction tank, the second reaction tank, the third reaction tank, and the fourth reaction tank is 1.5 h to 2.5 h, so that the total reaction time meets the requirements.

[0088] The features and performance of the present disclosure are further described in detail below with reference to the embodiments.

[0089] It should be noted that, in terms of mass fraction, the composition of the cobalt intermediates treated in the following examples is as follows: Co 30-40%, Al, Ca≤0.5%, H2O≤15%, and Mg≤5%.

[0090] Example 1

[0091] This embodiment provides a method for recovering a cobalt intermediate, comprising the following steps:

[0092] (1) Neutral leaching

[0093] The cobalt intermediate is mixed with water to prepare a cobalt intermediate slurry, and the mass fraction of the cobalt intermediate in the cobalt intermediate slurry is 13%. When the iron content in the cobalt intermediate is greater than 0.5%, the cobalt intermediate slurry is pumped into the reactor without adding ferrous sulfate, and the pH value of the reaction end point is controlled to be 5.0. The device shown in Figure 2 is used for leaching, with a total of seven reaction tanks, represented by AG. Tank A is an oxidation tank, which adds air, cobalt intermediate slurry, ferrous sulfate and sulfuric acid. Tank D adds cobalt intermediate slurry to adjust the pH value, and the material output from tank G is filtered and separated. The pH value of tank A is 1.0-1.5, the pH value of tank B is 1.5-2.0, the pH value of tank C is 2.0-2.5, the pH value of tank D is 3.5-4.0, the pH value of tank E is 4.0-5.0, the pH value of tank F is 5.0-5.4, and the pH value of tank G is 5.0-5.4. The temperature of each reaction tank is controlled at 60°C, and the slurry flow rate of tank A is 27m 3 / h, sulfuric acid flow rate 2.2m 3 / h, and the residence time of the five tanks is 1.5-1.6h. Neutral leaching residue and leaching liquid are produced, and the leaching liquid enters the next process.

[0094] According to the test, the leaching rate of cobalt after neutral leaching in this embodiment is 80%, and the cobalt content of the neutral leaching residue is 22% (mass fraction, the same below).

[0095] (2) Reduction acid leaching

[0096] Neutral leaching residue and water were slurried in a mass ratio of 1:3, stirred, and concentrated sulfuric acid was added. The temperature was raised to 70°C, and then sulfur dioxide was introduced for reduction leaching. The pH value was adjusted to 2.0 (online pH monitoring and on-site manual pH testing, the same below). The reaction time was 4 hours to obtain acid leaching residue and acid leaching solution. Leaching was carried out according to the method shown in Figure 3.

[0097] According to the test, the acid leaching residue in this embodiment contains 3% cobalt.

[0098] (3) High acid leaching

[0099] The acid leaching residue in step (2) is mixed with hydrogen peroxide and concentrated sulfuric acid for high acid leaching, the reaction temperature is controlled at 90° C., the pH value is controlled at 0.2, the molar ratio of the amount of hydrogen peroxide added to the cobalt metal content in the acid leaching residue is 1:2, and the cobalt metal in the acid leaching residue is further leached to obtain a cobalt-containing leachate which is reused in the leaching system.

[0100] According to the test, the slag contains 0.3% cobalt after high acid leaching.

[0101] (4) Copper removal

[0102] The acid leaching solution in step (2) is mixed with iron powder to reduce the copper ions in the solution to obtain sponge copper. After copper removal, the solution enters a continuous iron removal reaction tank. The amount of iron powder to be added is calculated according to the concentration of copper ions in the acid leaching solution so that the copper ion concentration in the solution after copper removal is 50 mg / L.

[0103] (5) Iron removal

[0104] The device in Figure 4 is used for continuous iron removal. The copper removal solution is mixed with air, cobalt carbonate and calcium carbonate for reaction. The amount of cobalt carbonate is adjusted to control the reaction pH value to 3.0-3.5. During the process, the Fe content in the system is kept at 3+ The concentration is less than 1g / L. The air flow rate is regulated according to the volume of the solution and the air flow rate is controlled to be 0.5NM. 3 / m 3 , control the reaction temperature to 80-90℃. By adjusting the amount of calcium sulfate, the concentration of the produced calcium sulfate crystals is 50g / m 3 .

[0105] The copper-removed liquid, air and cobalt carbonate were added to the first reaction tank, air, cobalt carbonate and calcium carbonate were added to the second reaction tank, air was added to the third reaction tank, and the material output from the fourth reaction tank was subjected to solid-liquid separation. The Fe content in the obtained liquid material was 0.04477 W / m. 3+ When the concentration is greater than 1g / L, it is returned to the first reaction tank, and the Fe 3+ If the concentration is less than 1g / L, it will not be returned. The air flow rate from the first reaction tank to the third reaction tank is 1NM 3 / m 3, 0.8NM 3 / m 3 , 0.5NM 3 / m 3 The pH values ​​of the first to third reaction tanks are 3.0, 3.2, and 3.5, respectively. The temperatures of the first to third reaction tanks are all 85°C. 3+ The concentration is less than 1 g / L. The residence time of the first reaction tank, the second reaction tank, the third reaction tank and the fourth reaction tank is 2 hours.

[0106] After testing, the iron ion concentration of the liquid after iron and aluminum removal is 3g / L, and the iron content in the iron-aluminum slag is 40% (mass fraction, the same below).

[0107] Example 2

[0108] This embodiment provides a method for recovering a cobalt intermediate, comprising the following steps:

[0109] (1) The cobalt intermediate is mixed with water to prepare a cobalt intermediate slurry, wherein the mass fraction of the cobalt intermediate in the cobalt intermediate slurry is 13%. When the iron content in the cobalt intermediate is less than 0.5%, the cobalt intermediate slurry is pumped into a reactor, and the cobalt intermediate slurry, concentrated sulfuric acid (mass fraction 98%, the same below) and ferrous sulfate are mixed in the reactor, wherein the mass ratio of the amount of ferrous sulfate added to the amount of cobalt metal in the cobalt intermediate is 5:100, and the pH value at the reaction end point is controlled to be 5.0. The apparatus of Figure 2 is used for leaching, with a total of seven reaction tanks, represented by AG. Tank A is an oxidation tank, into which air, cobalt intermediate slurry, ferrous sulfate and sulfuric acid are added. Tank D is used to add cobalt intermediate slurry to adjust the pH value, and the material output from tank G is subjected to filter press separation. The pH value of tank A is 1.0-1.5, the pH value of tank B is 1.5-2.0, the pH value of tank C is 2.0-2.5, the pH value of tank D is 3.5-4.0, the pH value of tank E is 4.0-5.0, the pH value of tank F is 5.0-5.4, and the pH value of tank G is 5.0-5.4. The temperature of each reaction tank is controlled at 60℃, and the slurry flow rate of tank A is 27m 3 / h, sulfuric acid flow rate 2.2m 3 / h, and the residence time of the five tanks is 1.5-1.6h. Neutral leaching residue and leaching liquid are produced, and the leaching liquid enters the next process.

[0110] According to tests, the leaching rate of cobalt after neutral leaching in this embodiment is 88%, and the cobalt content of the neutral leaching residue is 20%.

[0111] (2) Reduction acid leaching

[0112] Neutral leaching residue and water were slurried in a mass ratio of 1:4, stirred, and concentrated sulfuric acid was added. The temperature was raised to 70°C, and sulfur dioxide was then introduced for reduction leaching. The pH was adjusted to 1.5, and the reaction time was 4 hours to obtain acid leaching residue and acid leaching solution. Leaching was performed according to the method shown in Figure 3.

[0113] According to the test, the acid leaching residue in this embodiment contains 2.5% cobalt.

[0114] (3) High acid leaching

[0115] The acid leaching residue in step (2) is mixed with hydrogen peroxide and concentrated sulfuric acid for high acid leaching, the reaction temperature is controlled at 90° C., the pH value is controlled at 0.3, the molar ratio of the amount of hydrogen peroxide added to the cobalt metal content in the acid leaching residue is 1:2, and the cobalt metal in the acid leaching residue is further leached to obtain a cobalt-containing leachate which is reused in the leaching system.

[0116] According to the test, the slag contains 0.4% cobalt after high acid leaching.

[0117] (4) Copper removal

[0118] The acid leaching solution in step (2) is mixed with iron powder to reduce the copper ions in the solution to obtain sponge copper. After copper removal, the solution enters a continuous iron removal reaction tank. The amount of iron powder to be added is calculated according to the concentration of copper ions in the acid leaching solution so that the copper ion concentration in the solution after copper removal is 100 mg / L.

[0119] (5) Iron removal

[0120] The device in Figure 4 is used for continuous iron removal. The copper removal solution is mixed with air, cobalt carbonate and calcium carbonate for reaction. The amount of cobalt carbonate is adjusted to control the reaction pH value to 3.0-3.5. During the process, the Fe content in the system is kept at 3+ The concentration is less than 1g / L. The air flow rate is regulated according to the volume of the solution and the air flow rate is controlled to be 0.5NM. 3 / m 3 , control the reaction temperature to 80-90℃. By adjusting the amount of calcium sulfate, the concentration of the produced calcium sulfate crystals is 50g / m 3 .

[0121] The copper-removed liquid, air and cobalt carbonate were added to the first reaction tank, air, cobalt carbonate and calcium carbonate were added to the second reaction tank, air was added to the third reaction tank, and the material output from the fourth reaction tank was subjected to solid-liquid separation. The Fe content in the obtained liquid material was 0.04477 W / m. 3+ When the concentration is greater than 1g / L, it is returned to the first reaction tank, and the Fe 3+ If the concentration is less than 1g / L, it will not be returned. The air flow rate from the first reaction tank to the third reaction tank is 1NM 3 / m 3 , 0.8NM 3 / m 3 , 0.5NM 3 / m 3 The pH values ​​of the first to third reaction tanks are 3.0, 3.2, and 3.5, respectively. The temperatures of the first to third reaction tanks are all 85°C. 3+ The concentration is less than 1 g / L. The residence time of the first reaction tank, the second reaction tank, the third reaction tank and the fourth reaction tank is 2 hours.

[0122] After testing, the iron ion concentration of the liquid after iron and aluminum removal is 2g / L, and the iron content in the iron-aluminum slag is 42%.

[0123] Example 3

[0124] (1) The cobalt intermediate is mixed with water to prepare a cobalt intermediate slurry, wherein the mass fraction of the cobalt intermediate in the cobalt intermediate slurry is 15%. When the iron content in the cobalt intermediate is less than 0.5%, the cobalt intermediate slurry is pumped into a reactor, and the cobalt intermediate slurry, concentrated sulfuric acid (mass fraction 98%, the same below) and ferrous sulfate are mixed in the reactor, wherein the mass ratio of the amount of ferrous sulfate added to the amount of cobalt metal in the cobalt intermediate is 5:100, and the pH value at the reaction end point is controlled to be 5.4. The device shown in FIG2 is used for leaching, with a total of seven reaction tanks, represented by AG. Tank A is an oxidation tank, into which air, cobalt intermediate slurry, ferrous sulfate and sulfuric acid are added. Tank D is added to adjust the pH value, and the material output from tank G is subjected to filter press separation. The pH value of tank A is 1.0-1.5, the pH value of tank B is 1.5-2.0, the pH value of tank C is 2.0-2.5, the pH value of tank D is 3.5-4.0, the pH value of tank E is 4.0-5.0, the pH value of tank F is 5.0-5.4, and the pH value of tank G is 5.0-5.4. The temperature of each reaction tank is controlled at 60℃, and the slurry flow rate of tank A is 27m 3 / h, sulfuric acid flow rate 2.2m 3 / h, and the residence time of the five tanks is 1.5-1.6h. Neutral leaching residue and leaching liquid are produced, and the leaching liquid enters the next process.

[0125] According to tests, the cobalt leaching rate after neutral leaching in this embodiment is 90%, and the cobalt content of the neutral leaching residue is 18%.

[0126] (2) Reduction acid leaching

[0127] Neutral leaching residue and water were slurried in a mass ratio of 1:5, stirred, and concentrated sulfuric acid was added. The temperature was raised to 70°C, and sulfur dioxide was then introduced for reduction leaching. The pH was adjusted to 1.0, and the reaction time was 4 hours to obtain acid leaching residue and acid leaching solution. Leaching was performed according to the method shown in Figure 3.

[0128] According to the test, the acid leaching residue of this embodiment contains 2.0% cobalt.

[0129] (3) High acid leaching

[0130] The acid leaching residue in step (2) is mixed with hydrogen peroxide and concentrated sulfuric acid for high acid leaching, the reaction temperature is controlled at 90° C., the pH value is controlled at 0.4, the molar ratio of the amount of hydrogen peroxide added to the cobalt metal content in the acid leaching residue is 1:2, and the cobalt metal in the acid leaching residue is further leached to obtain a cobalt-containing leachate which is reused in the leaching system.

[0131] According to the test, the slag contains 0.3% cobalt after high acid leaching.

[0132] (4) Copper removal

[0133] The acid leaching solution in step (2) is mixed with iron powder to reduce the copper ions in the solution to obtain sponge copper. After copper removal, the solution enters a continuous iron removal reaction tank. The amount of iron powder to be added is calculated according to the concentration of copper ions in the acid leaching solution so that the copper ion concentration in the solution after copper removal is 200 mg / L.

[0134] (5) Iron removal

[0135] The device in Figure 4 is used for continuous iron removal. The copper removal solution is mixed with air, cobalt carbonate and calcium carbonate for reaction. The amount of cobalt carbonate is adjusted to control the reaction pH value to 3.0-3.5. During the process, the Fe content in the system is kept at 3+ The concentration is less than 1g / L. The air flow rate is regulated according to the volume of the solution and the air flow rate is controlled to be 0.5NM. 3 / m 3 , control the reaction temperature to 80-90℃. By adjusting the amount of calcium sulfate, the concentration of the produced calcium sulfate crystals is 50g / m 3 .

[0136] The copper-removed liquid, air and cobalt carbonate were added to the first reaction tank, air, cobalt carbonate and calcium carbonate were added to the second reaction tank, air was added to the third reaction tank, and the material output from the fourth reaction tank was subjected to solid-liquid separation. The Fe content in the obtained liquid material was 0.04477 W / m. 3+ When the concentration is greater than 1g / L, it is returned to the first reaction tank, and the Fe 3+ If the concentration is less than 1g / L, it will not be returned. The air flow rate from the first reaction tank to the third reaction tank is 1NM 3 / m 3 , 0.8NM 3 / m 3 , 0.5NM 3 / m 3 The pH values ​​of the first to third reaction tanks are 3.0, 3.2, and 3.5, respectively. The temperatures of the first to third reaction tanks are all 85°C. 3+ The concentration is less than 1 g / L. The residence time of the first reaction tank, the second reaction tank, the third reaction tank and the fourth reaction tank is 2 hours.

[0137] After testing, the iron ion concentration of the liquid after iron and aluminum removal is 1g / L, and the iron content in the iron-aluminum slag is 45%.

[0138] Example 4

[0139] The only difference from Example 1 is that when the neutral leaching cobalt intermediate contains less than 0.5% iron, ferrous sulfate accounting for 5% of the cobalt metal amount in the cobalt intermediate is added in a neutral leaching step.

[0140] The results show that this embodiment improves the leaching rate of cobalt metal from the original 80% to 88%.

[0141] Example 5

[0142] The only difference from Example 1 is that the neutral leaching pulping concentration is increased (the mass fraction of the cobalt intermediate in the cobalt intermediate slurry is 15%), and the endpoint pH value is regulated to 5.4.

[0143] The results show that the cobalt content in the neutral leaching residue is reduced from 22% to 18% in this embodiment, and increasing the pulping concentration is beneficial to improving the leaching rate.

[0144] Examples 6-8

[0145] The only difference from Example 1 is that in the reduction acid leaching, the solid-liquid ratio of the neutral leaching residue is adjusted from 1:3 to 1:5, and the pH values ​​of the reduction acid leaching in Examples 6-8 are adjusted to 1.0, 1.5, and 2.0, respectively.

[0146] The results showed that Examples 6-8 improved the leaching rate of cobalt in the second-stage reduction acid leaching, and the cobalt content in the acid leaching residue was 2.0%, 2.5%, and 3.0%, respectively.

[0147] Examples 9-10

[0148] The only difference from Example 1 is that in high acid leaching, the operating pH values ​​are adjusted to 0.4 and 0.3 respectively to improve the leaching rate of cobalt in high acid leaching.

[0149] The results showed that the cobalt content of the leached residues obtained after high acid leaching in Examples 9 and 10 was 0.5% and 0.4% respectively.

[0150] Examples 11-12

[0151] The only difference from Example 1 is that in the copper removal reaction, the copper ion concentration of the copper removal solution is maintained at different levels. In Examples 11-12, the copper ion concentration of the copper removal solution is controlled to be 100 mg / L and 200 mg / L, respectively.

[0152] The results showed that the iron ion concentration of the liquid after iron and aluminum removal in Examples 11-12 was 2 g / L and 1 g / L, and the iron content in the iron and aluminum slag was 42% and 45% respectively. Industrial Applicability

[0153] The present invention utilizes a three-stage leaching process involving neutral leaching, reductive acid leaching, and high-acid leaching to maximize the recovery of cobalt leached from cobalt intermediates and improve the recovery rate of valuable metals. Furthermore, by employing a continuous iron removal process, using cobalt carbonate or a cobalt intermediate as a neutralizer to adjust the pH value, and using calcium sulfate generated from calcium carbonate as a seed crystal, the crystallization rate for iron removal is increased, improving the filtration performance of the slag. The overall process is easy to operate and has excellent industrial applicability.

Claims

1. A method for recovering cobalt intermediates, characterized in that, it includes: Mixing the cobalt intermediate slurry and sulfuric acid, and performing neutral leaching under oxidation conditions, controlling the pH value of the leaching to be 5.0 - 5.4 to obtain neutral leaching residue and leachate after leaching; Performing reduction acid leaching on the neutral leaching residue to obtain acid leaching residue and acid leaching solution; Performing high - acid leaching on the acid leaching residue, controlling the pH value to be less than 0.5 to obtain high - acid leaching solution; Returning the high - acid leaching solution to the neutral leaching stage.

2. The recovery method according to claim 1, characterized in that, The process of the neutral leaching includes: Mixing the cobalt intermediate with water to make a slurry to obtain a cobalt intermediate slurry, the mass fraction of the cobalt intermediate in the cobalt intermediate slurry is 13% - 15%, mixing and reacting the cobalt intermediate slurry with sulfuric acid and an oxidant, controlling the leaching temperature to be 50°C - 70°C, and the reaction time to be 1.5h - 1.6h.

3. The recovery method according to claim 2, characterized in that, When the mass fraction of iron in the cobalt intermediate is less than 0.5%, ferrous sulfate is supplemented to participate in the reaction of the neutral leaching, and the mass ratio of the ferrous sulfate supplement amount to the cobalt metal amount in the cobalt intermediate is (4 - 6):

100.

4. The recovery method according to claim 2 or 3, characterized in that, During the neutral leaching process, multiple reaction kettles are connected in series. Add the cobalt intermediate slurry, sulfuric acid and an oxidant to the first reaction kettle, add the cobalt intermediate slurry to the intermediate reaction kettles, control the pH value of the leaching to be 5.0 - 5.4, and the residence time in each reaction kettle is 1.5h - 1.6h; When the mass fraction of iron in the cobalt intermediate is less than 0.5%, ferrous sulfate is added to the first reaction kettle.

5. The recovery method according to any one of claims 2 - 4, characterized in that, The oxidant is selected from at least one of oxygen - containing gas and hydrogen peroxide.

6. The recovery method according to claim 5, characterized in that, The oxygen - containing gas is selected from at least one of air and oxygen - enriched gas, and the volume fraction of oxygen in the oxygen - enriched gas is 21% - 90%.

7. The recovery method according to any one of claims 1 - 6, characterized in that, The process of the reduction acid leaching includes: Mixing and slurrying the neutral leaching residue with water, then mixing with sulfuric acid and a reducing agent, the leaching temperature is 60°C - 80°C, and the leaching time is greater than 2h.

8. The recovery method according to claim 7, characterized in that, The leaching temperature of the reduction acid leaching is 65°C - 75°C, the leaching time is 3h - 4h, and the leaching pH value is 1.5 - 2.

0.

9. The recovery method according to claim 7 or 8, characterized in that, The reducing agent is selected from at least one of sulfur dioxide, ammonium metabisulfite and hydrogen peroxide.

10. The recovery method according to any one of claims 7 - 9, characterized in that, The reducing agent is sulfur dioxide.

11. The recovery method according to claim 10, characterized in that, The dosage of sulfur dioxide is calculated according to the volume of the slurry, and the dosage of sulfur dioxide is 0.1 - 1 Nm 3 / m 3 .

12. The recovery method according to claim 10 or 11, characterized in that, The sulfur dioxide generated in the acid-making system is dried and compressed and then introduced into the reaction kettle for the reduction acid leaching.

13. The recovery method according to any one of claims 7-12, characterized in that, the mass ratio of the neutral leaching residue to water is 1:(3-5).

14. The recovery method according to any one of claims 1-13, characterized in that, the process of the high-acid leaching includes: mixing and reacting the acid leaching residue with hydrogen peroxide and sulfuric acid, controlling the reaction temperature at 85°C - 95°C, the reaction pH value at 0.25 - 0.45, and the leaching time at 4h - 5h.

15. The recovery method according to any one of claims 1-14, characterized in that, further comprising: mixing the acid leaching solution generated in the process of the reduction acid leaching with iron powder for copper removal reaction to obtain the solution after copper removal, and the solution after copper removal enters the iron removal process.

16. The recovery method according to claim 15, characterized in that, by adjusting the dosage of iron powder, the concentration of copper ions in the solution after copper removal is 50mg / L - 200mg / L.

17. The recovery method according to claim 15 or 16, characterized in that, The process of the iron removal step includes: mixing the post-copper-removal solution with an oxygen-containing gas, a neutralizing agent, and a nucleating agent for reaction, controlling the reaction pH value to be 3.0 - 3.5, and maintaining the concentration of Fe 3+ in the system to be less than 1 g / L.

18. The recovery method according to claim 17, characterized in that, in the iron removal process, the reaction temperature is controlled at 80°C - 90°C, and the reaction time is 1.5h - 3h.

19. The recovery method according to claim 17 or 18, characterized in that, the oxygen-containing gas is selected from at least one of air and oxygen-enriched gas, and the volume fraction of oxygen in the oxygen-enriched gas is 21% - 90%.

20. The recovery method according to claim 19, characterized in that, Adjust the flow rate of the oxygen-containing gas according to the volume of the solution, and the flow rate of the oxygen-containing gas is 0.1 NM 3 / m 3 -1.0 NM 3 / m 3 。 21. The recovery method according to any one of claims 17-20, characterized in that, the neutralizing agent is selected from at least one of cobalt carbonate and cobalt intermediate.

22. The recovery method according to any one of claims 17-21, characterized in that, the nucleating agent is calcium carbonate.

23. The recovery method according to claim 22, characterized in that, By controlling the dosage of the nucleating agent, the concentration of the generated calcium sulfate crystals is 1 g / m 3 -100 g / m 3 .

24. The recovery method according to any one of claims 17-23, characterized in that, The iron removal process is a continuous iron removal process, which includes a first reaction tank, a second reaction tank, a third reaction tank and a fourth reaction tank connected in series in sequence. The post-copper removal solution, the oxygen-containing gas and the neutralizing agent are added to the first reaction tank. The post-copper removal solution, the neutralizing agent and the nucleating agent are added to the second reaction tank. The oxygen-containing gas is added to the third reaction tank. The material output from the fourth reaction tank is subjected to solid-liquid separation, and when the Fe 3+ concentration in the obtained liquid material is greater than 1 g / L, it is returned to the first reaction tank.

25. The recovery method according to claim 24, characterized in that, the residence time of the first reaction tank, the second reaction tank, the third reaction tank and the fourth reaction tank is all 1.5h - 2.5h.

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