Method for short-range recovery of valuable metals from cobalt hydroxide raw material

Abstract

The invention discloses a method for short-range recovery of valuable metals from a cobalt hydroxide raw material, and belongs to the technical field of mineral valuable metal recovery. The method comprises the steps that cobalt hydroxide slurry formed by a cobalt hydroxide raw material and concentrated sulfuric acid are subjected to first-stage cobalt leaching, and first-stage cobalt leaching feed liquid is obtained; carrying out solid-liquid separation on the cobalt first-section leaching material liquid to obtain cobalt first-section leaching residues and cobalt first-section leaching liquid; pulping the cobalt first-stage leaching residues to obtain first slurry; the first slurry, an oxidizing agent and concentrated sulfuric acid are subjected to cobalt two-stage leaching, then ammonium bicarbonate is added to adjust the pH value, solid-liquid separation is conducted, and iron and aluminum slag and liquid obtained after iron and aluminum are removed are obtained; and iron powder or manganese powder is adopted for replacing copper in the iron and aluminum removed liquid, solid-liquid separation is conducted, and copper and the copper removed liquid are obtained. According to the method, the cobalt recovery rate can be effectively increased, valuable metal enrichment is achieved, the recovery rate of valuable metal can be increased, the technological process is short, the production cost is low, and technological control is easy.

Description

Technical Field

[0001] This invention relates to the field of mineral valuable metal recovery technology, and more specifically, to a method for short-range recovery of valuable metals from cobalt hydroxide raw materials. Background Technology

[0002] Cobalt has similar chemical properties to nickel, iron, manganese, and copper, and it often occurs together with other elements in natural minerals. Minerals containing cobalt are diverse, mainly including oxide minerals, arsenide minerals, and sulfide minerals.

[0003] Currently, the common process for extracting cobalt from minerals is pyrometallurgical enrichment followed by hydrometallurgical processing. Hydrometallurgy includes processes such as leaching, metal enrichment, and solution purification. Among these, leaching is a crucial step in hydrometallurgy, but existing technologies for leaching cobalt hydroxide suffer from problems such as low recovery rates of valuable metals and long production cycles.

[0004] In view of this, the present invention is proposed. Summary of the Invention

[0005] The purpose of this invention is to provide a method for short-range recovery of valuable metals from cobalt hydroxide raw materials, so as to solve or improve the above-mentioned technical problems.

[0006] This invention can be implemented as follows:

[0007] In a first aspect, the present invention provides a method for short-range recovery of valuable metals from cobalt hydroxide raw materials, comprising the following steps:

[0008] The cobalt hydroxide slurry formed from cobalt hydroxide raw material is subjected to cobalt-first leaching with concentrated sulfuric acid to obtain cobalt-first leaching solution.

[0009] The cobalt leaching solution is subjected to solid-liquid separation to obtain cobalt leaching residue and cobalt leaching solution.

[0010] The cobalt leaching residue is pulped to obtain the first slurry; the first slurry is then subjected to cobalt leaching in the second stage with an oxidant and concentrated sulfuric acid, followed by the addition of ammonium bicarbonate to adjust the pH value, and solid-liquid separation to obtain iron-aluminum slag and liquid after iron and aluminum removal.

[0011] Iron or manganese powder is used to replace the copper in the liquid after iron and aluminum removal, and solid-liquid separation is performed to obtain copper and the copper-removed liquid.

[0012] In an optional embodiment, the first-stage cobalt leaching includes a first acid leaching of cobalt hydroxide slurry with concentrated sulfuric acid to obtain a first acid leaching solution; and a second acid leaching of cobalt hydroxide slurry to be added to the first acid leaching solution to obtain a first-stage cobalt leaching solution.

[0013] The pH value of the first acid leaching is 1.0 to 2.5, and the first acid leaching time is ≥1 hour;

[0014] The pH value of the second acid leaching is 3.5 to 5.5, and the second acid leaching time is ≥1 hour.

[0015] In an optional embodiment, the first acid immersion includes a first acid immersion A stage, a first acid immersion B stage, and a first acid immersion C stage;

[0016] The pH value of the first acid leaching stage A is 1.0 to 1.5, the pH value of the first acid leaching stage B is 1.5 to 2.0, and the pH value of the first acid leaching stage C is 2.0 to 2.5.

[0017] In an optional embodiment, the second acid immersion includes a second acid immersion stage A, a second acid immersion stage B, a second acid immersion stage C, and a second acid immersion stage D.

[0018] The pH value of the second acid leaching stage A is 3.5-4.0, the pH value of the second acid leaching stage B is 4.0-4.5, the pH value of the second acid leaching stage C is 4.5-5.0, and the pH value of the second acid leaching stage D is 5.0-5.5.

[0019] In an optional embodiment, solid-liquid separation of the cobalt leaching solution includes dividing the cobalt leaching solution into cobalt leaching solution M and cobalt leaching solution N in a mass ratio of 1:2 to 1:3.5.

[0020] The cobalt leaching solution M is subjected to solid-liquid separation to obtain cobalt leaching residue M1 and cobalt leaching solution M2.

[0021] The cobalt leaching solution N is subjected to solid-liquid separation to obtain cobalt leaching residue N1 and cobalt leaching solution N2.

[0022] Among them, the cobalt first-stage leaching residue M1 is used to prepare pulp to obtain the first pulp; the cobalt first-stage leaching solution M2 is used to obtain the cobalt sulfate solution.

[0023] In an optional embodiment, the concentration of the first slurry is 15 wt% to 20 wt%.

[0024] In an optional embodiment, the cobalt two-stage leaching includes: adding concentrated sulfuric acid to the first slurry to adjust the pH value to 0.5 to 1.5, followed by adding an oxidant for reductive leaching;

[0025] The amount of oxidant used is 1.2 to 1.5 times the theoretical amount.

[0026] In an optional embodiment, after reduction leaching, ammonium bicarbonate is added to adjust the pH to 3.0–4.5.

[0027] In an optional embodiment, the amount of iron powder or manganese powder used is 0.8 to 1.2 times the theoretical amount.

[0028] In an optional implementation, the copper-removed solution is returned to the first acid leaching stage A for recycling.

[0029] In an optional embodiment, the mass ratio of the copper-removed liquid to the cobalt hydroxide slurry used for the first stage of cobalt leaching is 1:10 to 3:10.

[0030] In an optional embodiment, the cobalt leaching residue N1 is pulped to obtain a second slurry; concentrated sulfuric acid is added to the second slurry to adjust the pH value to 0.5-1.5, and then ammonium sulfite is added for reduction leaching to obtain a reduction leachate.

[0031] In an optional embodiment, the concentration of the second slurry is 15 wt% to 20 wt%.

[0032] In an optional embodiment, the amount of ammonium sulfite added is 0.8 to 1.1 times the theoretical amount.

[0033] In an optional implementation, the reduced leachate is used to be recycled back to the first acid leaching stage A.

[0034] In an optional embodiment, the mass ratio of the reducing leachate to the cobalt hydroxide slurry used for the first stage of cobalt leaching is 4:10 to 6:10.

[0035] In an optional embodiment, the cobalt hydroxide raw material contains ≥30% cobalt and ≤0.5wt% Al.

[0036] The beneficial effects of this invention include:

[0037] This invention combines the cobalt leaching process with the iron and aluminum removal process, alleviating the pressure of prolonged production cycles caused by the difficulty in pressing and filtering the leaching solution in the second stage. By directly adding ammonium bicarbonate to remove iron using the reaction heat of the cobalt leaching process, the steam consumption required for heating during separate iron removal processes can be avoided. Furthermore, it reduces the temperature drop of the solution caused by the need for pressing and filtering after the cobalt leaching process, thus helping to lower production costs. Simultaneously, using ammonium bicarbonate for iron removal reduces the cobalt content in the iron-aluminum slag, minimizing the loss of valuable cobalt and improving cobalt recovery. Moreover, the use of ammonium bicarbonate for iron removal does not introduce calcium ions, preventing calcium ion saturation in the cobalt sulfate solution and thus avoiding pipe blockage. Attached Figure Description

[0038] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0039] Figure 1 This is a first process flow diagram of the method for short-range recovery of valuable metals from cobalt hydroxide raw material provided by the present invention;

[0040] Figure 2 This is a second process flow diagram of the method for short-range recovery of valuable metals from cobalt hydroxide raw materials provided by the present invention. Detailed Implementation

[0041] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0042] The method for short-range recovery of valuable metals from cobalt hydroxide raw materials provided by the present invention will be described in detail below.

[0043] This invention provides a method for short-range recovery of valuable metals from cobalt hydroxide feedstock, combined with... Figure 1 and Figure 2 This includes the following steps:

[0044] S1: The cobalt hydroxide slurry formed from the cobalt hydroxide raw material is subjected to cobalt leaching with concentrated sulfuric acid to obtain cobalt leaching solution.

[0045] In some optional embodiments, the cobalt hydroxide raw material contains ≥30% cobalt and ≤0.5wt% Al. If the Al content in the cobalt hydroxide raw material exceeds 0.5%, colloids are easily formed, which is not conducive to subsequent solid-liquid separation.

[0046] In some alternative embodiments, the concentration of concentrated sulfuric acid can be 250 g / L to 300 g / L (e.g., 250 g / L, 260 g / L, 270 g / L, 280 g / L, 290 g / L or 300 g / L, etc.), and this concentration also applies to "concentrated sulfuric acid" as used below.

[0047] In some alternative embodiments, the cobalt hydroxide slurry described above can be obtained by mixing cobalt hydroxide raw material with water. For example, the mass ratio of cobalt hydroxide raw material to water can be 1:3, etc.

[0048] In some alternative embodiments, the first-stage cobalt leaching may include: subjecting a cobalt hydroxide slurry to concentrated sulfuric acid for a first acid leaching solution; and adding new cobalt hydroxide slurry to the first acid leaching solution for a second acid leaching to obtain a first-stage cobalt leaching solution.

[0049] The aforementioned first acid leaching stages A, B, and C all involve acid leaching the cobalt hydroxide slurry with concentrated sulfuric acid. Since the first stage of cobalt leaching is a continuous process, stages B and C extend the acid leaching reaction time and increase the leaching rate of the first stage of cobalt. The second acid leaching stage A primarily involves further adjusting the slurry obtained in the first stage C to achieve selective leaching. Further stages B through D ensure that cobalt is present in the first stage leaching solution, while valuable metals such as Fe, Al, and Cu are present in the first stage leaching residue. Stages B through D extend the adjustment reaction time.

[0050] The pH value of the first acid leaching can be 1.0–2.5, such as 1.0, 1.2, 1.5, 1.8, 2.0, 2.2, or 2.5, or other values ​​within the range of 1.0–2.5. The first acid leaching time is ≥1 hour, such as 1 hour to 2 hours. The pH value of the second acid leaching can be 3.5–5.5, such as 3.5, 3.8, 4.0, 4.2, 4.5, 4.8, 5.0, 5.2, or 5.5, or other values ​​within the range of 3.5–5.5. The second acid leaching time is ≥1 hour, such as 1 hour to 2 hours.

[0051] Setting the first and second acid leaching times to ≥1 hour ensures a high dissolution rate of metal ions.

[0052] In some optional embodiments, the first acid leaching may include a first acid leaching stage A, a first acid leaching stage B, and a first acid leaching stage C. The pH value of the first acid leaching stage A may be 1.0–1.5, such as 1.0, 1.1, 1.2, 1.3, 1.4, or 1.5, or other values ​​within the range of 1.0–1.5; the pH value of the first acid leaching stage B may be 1.5–2.0, such as 1.5, 1.6, 1.7, 1.8, 1.9, or 2.0, or other values ​​within the range of 1.5–2.0; and the pH value of the first acid leaching stage C may be 2.0–2.5, such as 2.0, 2.1, 2.2, 2.3, 2.4, or 2.5, or other values ​​within the range of 2.0–2.5.

[0053] In some alternative embodiments, the second acid immersion may include a second acid immersion stage A, a second acid immersion stage B, a second acid immersion stage C, and a second acid immersion stage D. The pH value of the second acid leaching stage A is 3.5–4.0, such as 3.5, 3.6, 3.7, 3.8, 3.9, or 4.0, or other values ​​within the range of 3.5–4.0; the pH value of the second acid leaching stage B can be 4.0–4.5, such as 4.0, 4.1, 4.2, 4.3, 4.4, or 4.5, or other values ​​within the range of 4.0–4.5; the pH value of the second acid leaching stage C can be 4.5–5.0, such as 4.5, 4.6, 4.7, 4.8, 4.9, or 5.0, or other values ​​within the range of 4.5–5.0; and the pH value of the second acid leaching stage D can be 5.0–5.5, such as 5.0, 5.1, 5.2, 5.3, 5.4, or 5.5, or other values ​​within the range of 5.0–5.5.

[0054] As the acid leaching reaction continues, concentrated sulfuric acid is constantly consumed, causing the pH value to increase. Therefore, the pH values ​​in stages A, B, and C of the first acid leaching process are different. Similarly, the pH values ​​in stages A, B, C, and D of the second acid leaching process are also different.

[0055] The reaction equations involved in the first and second acid leaching stages mentioned above both include Co(OH)2 + H2SO4 = CoSO4 + 2H2O.

[0056] In some alternative embodiments, the cobalt leaching process described above can be carried out in a leaching tank, with each acid leaching stage corresponding to a different leaching tank. In other words, the first acid leaching stage A to the second acid leaching stage D correspond to leaching tank A to leaching tank G in sequence.

[0057] For example, the cobalt leaching process can be carried out as follows: Cobalt hydroxide raw material is stirred and slurried with water to obtain cobalt hydroxide slurry. Cobalt hydroxide slurry and concentrated sulfuric acid are added to leaching tank A simultaneously. The flow rates of the added cobalt hydroxide slurry and concentrated sulfuric acid are controlled to maintain the pH value of the solution in leaching tank A. At the same time, stirring is turned on, and the solution overflows into leaching tank B. The solution in leaching tank B then overflows into leaching tank C, and the solution in leaching tank C then overflows into leaching tank D. New cobalt hydroxide slurry is added to leaching tank D, and the flow rate of the added cobalt hydroxide slurry is adjusted to control the pH value of the solution in leaching tank D. Subsequently, the solution in leaching tank D overflows into leaching tank E, the solution in leaching tank E then overflows into leaching tank F, and the solution in leaching tank F is then leached into leaching tank G.

[0058] S2: Perform solid-liquid separation on the cobalt leaching solution to obtain cobalt leaching residue and cobalt leaching solution.

[0059] In some alternative embodiments, the cobalt leaching solution can be subjected to uniform solid-liquid separation (e.g., pressure filtration) to obtain cobalt leaching residue and cobalt leaching solution.

[0060] In this method, the cobalt-first leaching residue is used to prepare a slurry to obtain a first slurry. The concentration of the first slurry can be, for example, 15wt% to 20wt%, such as 15wt%, 16wt%, 17wt%, 18wt%, 19wt%, or 20wt%. The cobalt-first leaching solution is used to obtain a cobalt sulfate solution, for example, by treating the cobalt-first leaching solution through a precision filter to obtain a cobalt sulfate solution.

[0061] In some alternative embodiments, the cobalt leaching solution can be divided into cobalt leaching solution M and cobalt leaching solution N in a mass ratio of 1:2 to 1:3.5, and then the cobalt leaching solution M and cobalt leaching solution N are subjected to solid-liquid separation (e.g., pressure filtration).

[0062] The reason for dividing the cobalt leaching solution into cobalt leaching solution M and cobalt leaching solution N is that the route corresponding to cobalt leaching solution M is mainly used to avoid excessive iron and aluminum content, which would lead to iron and aluminum enrichment and affect product quality; the route corresponding to cobalt leaching solution N is mainly used for material return, and by controlling the amount of material return, it is beneficial to the enrichment of Cu.

[0063] Among them, after filtration, the first-stage cobalt leaching solution M yields first-stage cobalt leaching residue M1 and first-stage cobalt leaching solution M2; after filtration, the first-stage cobalt leaching solution N yields first-stage cobalt leaching residue N1 and first-stage cobalt leaching solution N2.

[0064] S3: The cobalt leaching solution M2 described above is used to obtain a cobalt sulfate solution. For example, the cobalt leaching solution M2 is processed through a precision filter to obtain a cobalt sulfate solution. Similarly, the cobalt leaching solution N2 described above can also be used to obtain a cobalt sulfate solution. For example, the cobalt leaching solution N2 is processed through a precision filter to obtain a cobalt sulfate solution.

[0065] S4: The cobalt leaching residue from stage one is pulped to obtain the first slurry; the first slurry is then subjected to cobalt stage two leaching with an oxidant and concentrated sulfuric acid, followed by the addition of ammonium bicarbonate to adjust the pH value, and solid-liquid separation (e.g., pressure filtration) to obtain iron-aluminum slag and a liquid after iron and aluminum removal. Copper in the liquid after iron and aluminum removal is replaced with iron powder or manganese powder, and solid-liquid separation (e.g., pressure filtration) is performed to obtain copper (e.g., sponge copper) and a liquid after copper removal.

[0066] In some alternative embodiments, the concentration of the first slurry may be, for example, 15 wt% to 20 wt%, such as 15 wt%, 16 wt%, 17 wt%, 18 wt%, 19 wt%, or 20 wt%.

[0067] In this invention, when all the cobalt leaching solution in S2 is uniformly filtered to obtain cobalt leaching residue and cobalt leaching solution, all the cobalt leaching residue is then pulped to obtain the first pulp.

[0068] When the cobalt leaching solution in S2 is divided into cobalt leaching solution M and cobalt leaching solution N, the cobalt leaching residue M1 is pulped to obtain the first pulp.

[0069] In some alternative embodiments, cobalt leaching may include adding concentrated sulfuric acid to a first slurry to adjust the pH to 0.5 to 1.5 (e.g., 0.5, 0.8, 1.0, 1.2, or 1.5), followed by adding an oxidant for cobalt leaching.

[0070] The chemical reaction equations involved in this process include:

[0071] 2Fe(OH)3+3H2SO4=Fe2(SO4)3+6H2O;

[0072] Cu(OH)₂ + H₂SO₄ = CuSO₄ + 2H₂O;

[0073] 2Co(OH)3+H2O2+2H2SO4→2CoSO4+6H2O+O2↑.

[0074] The oxidant may include at least one of hydrogen peroxide, ammonium sulfite, and ammonium metabisulfite. The amount of oxidant used may be 1.2 to 1.5 times the theoretical amount, such as 1.2, 1.3, 1.4, or 1.5 times, or other values ​​within the range of 1.2 to 1.5 times.

[0075] In some alternative embodiments, after reductive leaching, ammonium bicarbonate is added to adjust the pH to 3.0–4.5, such as 3.0, 3.2, 3.5, 3.8, 4.0, 4.2, or 4.5, or other values ​​within the range of 3.0–4.5. The addition of ammonium bicarbonate neutralizes the pH, resulting in iron-aluminum slag containing both iron hydroxide and aluminum hydroxide.

[0076] It should be noted that if calcium carbonate is used instead of ammonium bicarbonate, the Ca content in the reaction solution will increase, and the amount of iron-aluminum slag will increase, thus reducing the main iron content in the iron-aluminum slag.

[0077] The chemical reaction equations involved in the replacement of copper in the solution after iron or aluminum removal by iron or manganese powder include:

[0078] Fe+Cu 2+ =Fe 2+ +Cu;

[0079] Mn+Cu2+ =Mn 2+ +Cu.

[0080] In some alternative implementations, the amount of iron powder used can be 0.8 to 1.2 times the theoretical amount, such as 0.8, 0.9, 1.0, 1.1 or 1.2 times, or other values ​​within the range of 0.8 to 1.2 times.

[0081] In some alternative embodiments, the copper-removed solution can be returned to the first acid leaching stage A for recycling. For example, after the copper-removed solution is returned to the first acid leaching stage A, the reaction temperature of the first acid leaching stage A can be controlled to not exceed 90°C, for example, 30°C to 90°C.

[0082] In some alternative embodiments, the mass ratio of the copper-removed liquid to the cobalt hydroxide slurry used for the first stage of cobalt leaching can be from 1:10 to 3:10, such as 1:10, 1.5:10, 2:10, 2.5:10 or 3:10, or other values ​​within the range of 1:10 to 3:10.

[0083] S5: When the cobalt leaching solution in S2 is divided into cobalt leaching solution M and cobalt leaching solution N, the cobalt leaching residue N1 can be pulped to obtain a second pulp. Concentrated sulfuric acid is added to the second pulp to adjust the pH value to 0.5-1.5 (such as 0.5, 0.8, 1.0, 1.2 or 1.5, etc.), and then ammonium sulfite is added for reduction leaching to obtain a reduced leaching solution.

[0084] The chemical reaction equations involved in this process include:

[0085] 2Fe(OH)3+3H2SO4=Fe2(SO4)3+6H2O;

[0086] Cu(OH)₂ + H₂SO₄ = CuSO₄ + 2H₂O;

[0087] 2Co 3+ +SO3 2- +3H₂O→2Co 2+ +SO4 2- +6H + .

[0088] The concentration of the second slurry can be 15wt% to 20wt%, such as 15wt%, 16wt%, 17wt%, 18wt%, 19wt%, or 20wt%, or other values ​​within the range of 15wt% to 20wt%.

[0089] In some alternative embodiments, the amount of ammonium sulfite added can be 0.8 to 1.1 times the theoretical amount, such as 0.8, 0.9, 1.0 or 1.1 times, or other values ​​within the range of 0.8 to 1.1 times.

[0090] In some alternative embodiments, the reduced leachate is recycled back to the first acid leaching stage A. Exemplarily, after the reduced leachate is returned to the first acid leaching stage A, the reaction temperature of the first acid leaching stage A can be controlled to not exceed 90°C, for example, 30°C to 90°C.

[0091] In some alternative embodiments, the mass ratio of the reducing leachate to the cobalt hydroxide slurry used for cobalt primary leaching can be from 4:10 to 6:10, such as 4:10, 4.5:10, 5:10, 5.5:10 or 6:10, or other values ​​within the range of 4:10 to 6:10.

[0092] Building upon the above, this invention combines the cobalt leaching process with the iron and aluminum removal process, alleviating the pressure of extended production cycles caused by the difficulty in pressing and filtering the leaching solution in the second stage. By directly adding ammonium bicarbonate to remove iron using the reaction heat of the cobalt leaching process, the steam consumption required for heating during separate iron removal processes can be avoided. Furthermore, it reduces the temperature drop of the leaching solution caused by the need for pressing and filtering after cobalt leaching, thus helping to lower production costs. Simultaneously, the use of ammonium bicarbonate for iron removal significantly reduces the cobalt content in the iron-aluminum slag, minimizing the loss of valuable cobalt and increasing the cobalt recovery rate to 99%. In addition, the use of ammonium bicarbonate for iron removal does not introduce calcium ions, preventing calcium ion saturation in the cobalt sulfate solution and thus avoiding pipe blockage.

[0093] When the cobalt leaching solution in S2 is divided into cobalt leaching solution M and cobalt leaching solution N, ammonium sulfite is used for reductive leaching. Ammonium sulfite is added directly using the reaction heat from concentrated sulfuric acid, eliminating the need for additional steam heating and thus reducing steam consumption. In this reductive leaching process, iron ions in the cobalt leaching residue N1 are first dissolved in the solution using concentrated sulfuric acid, followed by the addition of ammonium sulfite for reductive leaching. Because ammonium sulfite has strong reducing properties, it preferentially reacts with ions with stronger oxidizing properties. The standard electrode potential of trivalent iron is higher than that of trivalent cobalt, but in the actual reaction process... Ferrous iron is more easily activated by oxidation, so ammonium sulfite will first reduce ferric iron to ferrous iron, and then reduce cobalt. Therefore, after adding ammonium sulfite, ferrous ions are present in the solution, returning the reduction leaching solution to the first acid leaching stage A. Under acidic conditions, it will react with cobalt in the cobalt hydroxide slurry, increasing the cobalt leaching rate in the first stage of cobalt leaching, making more cobalt present in the solution, and reducing the cobalt content in the first stage leaching residue. In addition, since ferric cobalt exists in solid form, the amount of cobalt leaching residue in the first stage of cobalt leaching is reduced after being reduced by ferrous iron, which can reduce the amount of cobalt recovery auxiliary materials used in the second stage of cobalt reduction leaching, thus reducing production costs.

[0094] Furthermore, the present invention returns the reduced leaching solution to the first acid leaching stage A, which helps to reduce the reaction temperature of the first acid leaching stage A. The first acid leaching stage A uses concentrated sulfuric acid to dissolve cobalt hydroxide slurry, and the reaction process is exothermic, with the temperature of the reaction tank reaching as high as 80°C, and as high as 95°C in summer. The return operation can reduce the reaction temperature in the above-mentioned reaction tank, reduce the operating pressure of the equipment, and extend the service life of the equipment. At the same time, the return process is conducive to the enrichment of valuable metals such as Fe and Cu in the solution after iron and aluminum removal, improving the recovery efficiency of valuable metals, reducing the amount of iron and aluminum slag, and reducing the cost of solid waste treatment.

[0095] The features and performance of the present invention will be further described in detail below with reference to embodiments.

[0096] Example 1

[0097] This embodiment provides a method for short-range recovery of valuable metals from cobalt hydroxide feedstock, such as... Figure 1 As shown, the method includes:

[0098] S1: The cobalt hydroxide slurry formed from the cobalt hydroxide raw material is subjected to cobalt leaching with concentrated sulfuric acid to obtain cobalt leaching solution.

[0099] Specifically as follows:

[0100] S1-1: Cobalt hydroxide raw material and water are stirred and slurried at a mass ratio of 1:3 to obtain cobalt hydroxide slurry.

[0101] The main components and contents of the above-mentioned cobalt hydroxide raw materials are shown in Table 1.

[0102] Table 1. Main components and their content (wt%)

[0103]

[0104]

[0105] S1-2: Cobalt hydroxide slurry and concentrated sulfuric acid (concentration of 300 g / L) are added to leaching tank A simultaneously. The flow rates of the added cobalt hydroxide slurry and concentrated sulfuric acid are controlled to maintain the pH value of the solution in leaching tank A at 1.0. At the same time, stirring is turned on (stirring speed of 350 rpm) to carry out the first acid leaching stage A. Subsequently, the solution in leaching tank A overflows into leaching tank B for the first acid leaching stage B. The solution in leaching tank B overflows into leaching tank C for the first acid leaching stage C, thus obtaining the first acid leaching solution.

[0106] The pH value of the solution in leaching tank B is 1.5, the pH value of the solution in leaching tank C is 2.0, and the total reaction time from leaching tank A to leaching tank C is 1 hour.

[0107] S1-3: The solution in leaching tank C overflows into leaching tank D. New cobalt hydroxide slurry (the same cobalt hydroxide slurry in S11) is added to leaching tank D. The flow rate of the added cobalt hydroxide slurry is adjusted to control the pH value of the solution in leaching tank D to be maintained at 4.0 for the second acid leaching stage A. The solution in leaching tank D overflows into leaching tank E for the second acid leaching stage B. The solution in leaching tank E overflows into leaching tank F for the second acid leaching stage C. The solution in leaching tank F overflows into leaching tank G for the second acid leaching stage D, resulting in a cobalt first-stage leaching solution.

[0108] The pH value of the solution in leaching tank E is 4.5, the pH value range of the solution in leaching tank F is 5.0, and the total reaction time from leaching tank D to leaching tank G is 1 hour.

[0109] S2: Perform solid-liquid separation on the cobalt leaching solution to obtain cobalt leaching residue and cobalt leaching solution.

[0110] Specifically as follows:

[0111] S2-1: After the leaching tank G is full, the cobalt leaching solution in the leaching tank G is divided into cobalt leaching solution M and cobalt leaching solution N in a mass ratio of 1:2.

[0112] S2-2: The first stage cobalt leaching solution M is fed into the first filter press to obtain the first stage cobalt leaching residue M1 and the first stage cobalt leaching solution M2; the first stage cobalt leaching solution N is fed into the second filter press to obtain the first stage cobalt leaching residue N1 and the first stage cobalt leaching solution N2.

[0113] S3: Cobalt leaching solution M2 and cobalt leaching solution N2 are both filtered through a precision filter to obtain cobalt sulfate solution.

[0114] S4-1: The cobalt stage leaching residue M1 is mixed with water at a mass ratio of 1:4 to obtain a first slurry with a concentration of 20wt%. The first slurry is transferred to the cobalt stage leaching X tank, and concentrated sulfuric acid is added to adjust the pH of the solution in the cobalt stage leaching X tank to 1.0. Then hydrogen peroxide (the amount of hydrogen peroxide used is 1.4 times the theoretical amount) is added to carry out the cobalt stage leaching. When the cobalt stage leaching reaches the reaction endpoint, ammonium bicarbonate solid is added to adjust the pH value. When the pH value is 3.5, the addition of ammonium bicarbonate is stopped. Then the mixture is filtered to obtain iron-aluminum slag and the liquid after iron and aluminum removal.

[0115] S4-2: Transfer the liquid after iron and aluminum removal to the copper removal reaction tank, add iron powder (the amount of iron powder added is 0.8 times the theoretical amount) to the copper removal reaction tank to replace the copper in the liquid after iron and aluminum removal; after the replacement is completed, pass it through the copper removal filter press to obtain sponge copper and copper removal liquid.

[0116] S4-3: The copper-removed liquid is returned to the first acid leaching stage A for recycling. The copper-removed liquid is returned at a mass ratio of 2:10 with the cobalt hydroxide slurry used for the first stage of cobalt leaching. After the return, the temperature of the leaching tank A is controlled at 80℃.

[0117] S5: The cobalt stage leaching residue N1 is mixed with water at a mass ratio of 1:4 to obtain a second slurry with a concentration of 20wt%. The second slurry is transferred to the cobalt stage leaching tank Y, and concentrated sulfuric acid is added to adjust the pH of the solution in the cobalt stage leaching tank Y to 1.0. Then, ammonium sulfite is added for reductive leaching (the amount of ammonium sulfite is 1.0 times the theoretical amount). When the reductive leaching reaches the reaction endpoint, the obtained reductive leaching solution is returned to the first acid leaching stage A for recycling. The reductive leaching solution is returned at a mass ratio of 5:10 to the cobalt hydroxide slurry used for the cobalt stage leaching. After the return, the temperature of the leaching tank A is controlled at 80℃.

[0118] Example 2

[0119] This embodiment provides a method for short-range recovery of valuable metals from cobalt hydroxide feedstock, including:

[0120] S1: The cobalt hydroxide slurry formed from the cobalt hydroxide raw material is subjected to cobalt leaching with concentrated sulfuric acid to obtain cobalt leaching solution.

[0121] Specifically as follows:

[0122] S1-1: Same as S1-1 in Example 1.

[0123] S1-2: Cobalt hydroxide slurry and concentrated sulfuric acid (concentration of 250 g / L) are added to leaching tank A simultaneously. The flow rates of the added cobalt hydroxide slurry and concentrated sulfuric acid are controlled to maintain the pH value of the solution in leaching tank A at 1.2. At the same time, stirring is turned on (stirring speed of 350 rpm) to carry out the first acid leaching stage A. Subsequently, the solution in leaching tank A overflows into leaching tank B for the first acid leaching stage B. The solution in leaching tank B overflows into leaching tank C for the first acid leaching stage C, thus obtaining the first acid leaching solution.

[0124] The pH value of the solution in leaching tank B is 1.8, the pH value of the solution in leaching tank C is 2.2, and the total reaction time from leaching tank A to leaching tank C is 1.5 hours.

[0125] S1-3: The solution in leaching tank C overflows into leaching tank D. New cobalt hydroxide slurry (the same cobalt hydroxide slurry in S11) is added to leaching tank D. The flow rate of the added cobalt hydroxide slurry is adjusted to control the pH value of the solution in leaching tank D to be maintained at 3.8 for the second acid leaching stage A. The solution in leaching tank D overflows into leaching tank E for the second acid leaching stage B. The solution in leaching tank E overflows into leaching tank F for the second acid leaching stage C. The solution in leaching tank F overflows into leaching tank G for the second acid leaching stage D, resulting in a cobalt first-stage leaching solution.

[0126] The pH value of the solution in leaching tank E is 4.2, the pH value range of the solution in leaching tank F is 5.2, and the total reaction time from leaching tank D to leaching tank G is 1.5 hours.

[0127] S2: Perform solid-liquid separation on the cobalt leaching solution to obtain cobalt leaching residue and cobalt leaching solution.

[0128] Specifically as follows:

[0129] S2-1: After the leaching tank G is full, the cobalt leaching solution in the leaching tank G is divided into cobalt leaching solution M and cobalt leaching solution N in a mass ratio of 1:3.

[0130] S2-2: The first stage cobalt leaching solution M is fed into the first filter press to obtain the first stage cobalt leaching residue M1 and the first stage cobalt leaching solution M2; the first stage cobalt leaching solution N is fed into the second filter press to obtain the first stage cobalt leaching residue N1 and the first stage cobalt leaching solution N2.

[0131] S3: Cobalt leaching solution M2 and cobalt leaching solution N2 are both filtered through a precision filter to obtain cobalt sulfate solution.

[0132] S4-1: The cobalt stage leaching residue M1 is mixed with water at a mass ratio of 1:5 to prepare a first slurry with a concentration of approximately 16.6 wt%. The first slurry is transferred to the cobalt stage leaching tank X, and concentrated sulfuric acid is added to adjust the pH of the solution in the cobalt stage leaching tank X to 1.2. Then, ammonium sulfite (the amount of ammonium sulfite is 1.2 times the theoretical amount) is added to carry out the cobalt stage leaching. When the cobalt stage leaching reaches the reaction endpoint, solid ammonium bicarbonate is added to adjust the pH. When the pH is 3.0, the addition of ammonium bicarbonate is stopped. Then, the mixture is filtered to obtain iron-aluminum slag and the liquid after iron and aluminum removal.

[0133] S4-2: Transfer the liquid after iron and aluminum removal to the copper removal reaction tank, add iron powder (the amount of iron powder added is 0.8 times the theoretical amount) to the copper removal reaction tank to replace the copper in the liquid after iron and aluminum removal; after the replacement is completed, pass it through the copper removal filter press to obtain sponge copper and copper removal liquid.

[0134] S4-3: The copper-removed liquid is returned to the first acid leaching stage A for recycling. The copper-removed liquid is returned at a mass ratio of 1:10 with the cobalt hydroxide slurry used for the first stage of cobalt leaching. After the return, the temperature of the leaching tank A is controlled at 50℃.

[0135] S5: The cobalt stage leaching residue N1 is mixed with water at a mass ratio of 1:4 to obtain a second slurry with a concentration of 20wt%. The second slurry is transferred to the cobalt stage leaching tank Y, and concentrated sulfuric acid is added to adjust the pH of the solution in the cobalt stage leaching tank Y to 0.5. Then ammonium sulfite is added for reduction leaching (the amount of ammonium sulfite is 0.8 times the theoretical amount). When the reduction leaching reaches the reaction endpoint, the obtained reduction leaching solution is returned to the first acid leaching stage A for recycling. The reduction leaching solution is returned at a mass ratio of 4:10 to the cobalt hydroxide slurry used for the cobalt stage leaching. After the return, the temperature of the leaching tank A is controlled at 50℃.

[0136] Example 3

[0137] This embodiment provides a method for short-range recovery of valuable metals from cobalt hydroxide feedstock, including:

[0138] S1: The cobalt hydroxide slurry formed from the cobalt hydroxide raw material is subjected to cobalt leaching with concentrated sulfuric acid to obtain cobalt leaching solution.

[0139] Specifically as follows:

[0140] S1-1: Same as S1-1 in Example 1.

[0141] S1-2: Cobalt hydroxide slurry and concentrated sulfuric acid (concentration of 280 g / L) are added to leaching tank A simultaneously. The flow rates of the added cobalt hydroxide slurry and concentrated sulfuric acid are controlled to maintain the pH value of the solution in leaching tank A at 1.5. At the same time, stirring is turned on (stirring speed of 350 rpm) to carry out the first acid leaching stage A. Subsequently, the solution in leaching tank A overflows into leaching tank B for the first acid leaching stage B. The solution in leaching tank B overflows into leaching tank C for the first acid leaching stage C, thus obtaining the first acid leaching solution.

[0142] The pH value of the solution in leaching tank B is 2.0, the pH value of the solution in leaching tank C is 2.5, and the total reaction time from leaching tank A to leaching tank C is 2 hours.

[0143] S1-3: The solution in leaching tank C overflows into leaching tank D. New cobalt hydroxide slurry (the same cobalt hydroxide slurry in S11) is added to leaching tank D. The flow rate of the added cobalt hydroxide slurry is adjusted to control the pH value of the solution in leaching tank D to be maintained at 4.0 for the second acid leaching stage A. The solution in leaching tank D overflows into leaching tank E for the second acid leaching stage B. The solution in leaching tank E overflows into leaching tank F for the second acid leaching stage C. The solution in leaching tank F overflows into leaching tank G for the second acid leaching stage D, resulting in a cobalt first-stage leaching solution.

[0144] The pH value of the solution in leaching tank E is 4.5, the pH value range of the solution in leaching tank F is 5.5, and the total reaction time from leaching tank D to leaching tank G is 2 hours.

[0145] S2: Perform solid-liquid separation on the cobalt leaching solution to obtain cobalt leaching residue and cobalt leaching solution.

[0146] Specifically as follows:

[0147] S2-1: After the leaching tank G is full, the cobalt leaching solution in the leaching tank G is divided into cobalt leaching solution M and cobalt leaching solution N at a mass ratio of 1:3.5.

[0148] S2-2: The first stage cobalt leaching solution M is fed into the first filter press to obtain the first stage cobalt leaching residue M1 and the first stage cobalt leaching solution M2; the first stage cobalt leaching solution N is fed into the second filter press to obtain the first stage cobalt leaching residue N1 and the first stage cobalt leaching solution N2.

[0149] S3: Cobalt leaching solution M2 and cobalt leaching solution N2 are both filtered through a precision filter to obtain cobalt sulfate solution.

[0150] S4-1: The cobalt stage leaching residue M1 is mixed with water at a mass ratio of 1:4.5 to prepare a first slurry with a concentration of approximately 18.2 wt%. The first slurry is transferred to the cobalt stage leaching tank X, and concentrated sulfuric acid is added to adjust the pH of the solution in the cobalt stage leaching tank X to 1.5. Then, ammonium metabisulfite (the amount of ammonium metabisulfite is 1.5 times the theoretical amount) is added to carry out the cobalt stage leaching. When the cobalt stage leaching reaches the reaction endpoint, solid ammonium bicarbonate is added to adjust the pH. When the pH is 4.5, the addition of ammonium bicarbonate is stopped. Then, the mixture is filtered to obtain iron-aluminum slag and the liquid after iron and aluminum removal.

[0151] S4-2: Transfer the liquid after iron and aluminum removal to the copper removal reaction tank, add manganese powder (the amount of manganese powder added is 1.2 times the theoretical amount) to the copper removal reaction tank to replace the copper in the liquid after iron and aluminum removal; after the replacement is completed, pass through the copper removal filter press to obtain sponge copper and copper removal liquid.

[0152] S4-3: The copper-removed liquid is returned to the first acid leaching stage A for recycling. The copper-removed liquid is returned at a mass ratio of 3:10 with the cobalt hydroxide slurry used for the first stage of cobalt leaching. After the return, the temperature of the leaching tank A is controlled at 30℃.

[0153] S5: The cobalt stage leaching residue N1 is mixed with water at a mass ratio of 1:5 to prepare a second slurry with a concentration of approximately 16.6 wt%. The second slurry is transferred to the cobalt stage leaching tank Y, and concentrated sulfuric acid is added to adjust the pH of the solution in the cobalt stage leaching tank Y to 1.5. Then, ammonium sulfite is added for reductive leaching (the amount of ammonium sulfite used is 1.1 times the theoretical amount). When the reductive leaching reaches the reaction endpoint, the obtained reductive leaching solution is returned to the first acid leaching stage A for recycling. The reductive leaching solution is returned at a mass ratio of 6:10 to the cobalt hydroxide slurry used for the cobalt stage leaching. After the return, the temperature of the leaching tank A is controlled at 30°C.

[0154] Example 4

[0155] This embodiment provides a method for short-range recovery of valuable metals from cobalt hydroxide feedstock, such as... Figure 2 As shown, the method includes:

[0156] S1: Same as S1 in Example 1.

[0157] S2: After the leaching tank G is full, feed the cobalt first-stage leaching solution in the leaching tank G into the filter press to obtain cobalt first-stage leaching residue and cobalt first-stage leaching solution.

[0158] S3: Cobalt leaching solution is obtained by passing it through a precision filter to obtain cobalt sulfate solution.

[0159] S4-1: The cobalt leaching residue from stage 1 is mixed with water at a mass ratio of 1:4 to obtain a first slurry with a concentration of 20wt%. The first slurry is transferred to the cobalt stage 2 leaching tank, and concentrated sulfuric acid is added to adjust the pH of the solution in the cobalt stage 2 leaching tank to 1.0. Then hydrogen peroxide (the amount of hydrogen peroxide used is 1.4 times the theoretical amount) is added to carry out cobalt stage leaching. When the cobalt stage leaching reaches the reaction endpoint, ammonium bicarbonate solid is added to adjust the pH value. When the pH value is 3.5, the addition of ammonium bicarbonate is stopped. Then the mixture is filtered to obtain iron-aluminum slag and the liquid after iron and aluminum removal.

[0160] S4-2: Same as S4-2 in Example 1.

[0161] S4-3: Same as S4-3 in Example 1.

[0162] Example 5

[0163] The difference between this embodiment and Embodiment 1 is that the first acid leaching process is carried out only in leaching tank A, and the first acid leaching time is kept constant by increasing the volume of leaching tank A.

[0164] Example 6

[0165] The difference between this embodiment and Embodiment 1 is that the second acid leaching process is carried out only in the leaching tank D, and the second acid leaching time is kept constant by increasing the volume of the leaching tank D.

[0166] Example 7

[0167] The difference between this embodiment and Embodiment 1 is that the cobalt leaching process only involves the first acid leaching process and does not involve the second acid leaching process.

[0168] Comparative Example 1

[0169] This comparative example provides a method for short-range recovery of valuable metals from cobalt hydroxide feedstock, including:

[0170] S1: Same as S1 in Example 1.

[0171] S2: After the leaching tank G is full, feed the cobalt first-stage leaching solution in the leaching tank G into the filter press to obtain cobalt first-stage leaching residue and cobalt first-stage leaching solution.

[0172] S3: After passing through a precision filter, the cobalt leaching solution from the first stage yields a cobalt sulfate solution.

[0173] S4-1: The cobalt stage leaching residue and water are mixed at a mass ratio of 1:4 to obtain a first slurry with a concentration of 20wt%. The first slurry is transferred to the cobalt stage leaching tank, and concentrated sulfuric acid is added to adjust the pH of the solution in the cobalt stage leaching tank to 1.0. Then hydrogen peroxide (the amount of hydrogen peroxide used is 1.4 times the theoretical amount) is added to carry out cobalt stage leaching. When the cobalt stage leaching reaches the reaction endpoint, it is filtered under pressure to obtain cobalt stage leaching residue and cobalt stage leaching solution.

[0174] S4-2: The cobalt stage leaching solution is pumped to the iron and aluminum removal tank, heated to 70°C, and calcium carbonate solution is added for pH adjustment. When the pH of the solution reaches 3.5-4.0, the addition of calcium carbonate is stopped. After filtration by a filter press, iron and aluminum slag and iron and aluminum removal liquid are obtained.

[0175] S4-3: Transfer the liquid after iron and aluminum removal to the copper removal reaction tank, add iron powder (the amount of iron powder added is 0.7 times the theoretical amount) to the copper removal reaction tank to replace the copper in the liquid after iron and aluminum removal; after the replacement is completed, pass it through the copper removal filter press to obtain sponge copper and copper removal liquid.

[0176] Comparative Example 2

[0177] This comparative example provides a method for short-range recovery of valuable metals from cobalt hydroxide feedstock, including:

[0178] S1: Same as S1 in Example 1.

[0179] S2: After the leaching tank G is full, feed the cobalt first-stage leaching solution in the leaching tank G into the filter press to obtain cobalt first-stage leaching residue and cobalt first-stage leaching solution.

[0180] S3: After passing through a precision filter, the cobalt leaching solution from the first stage yields a cobalt sulfate solution.

[0181] S4-1: Same as S4-1 in Comparative Example 1.

[0182] S4-2: The cobalt stage leaching solution is pumped to the iron and aluminum removal tank, heated to 70°C, and ammonium bicarbonate solution is added for pH adjustment. When the pH of the solution reaches 3.5-4.0, the addition of ammonium bicarbonate is stopped. After filtration by a filter press, iron and aluminum slag and iron and aluminum removal liquid are obtained.

[0183] S4-3: Same as S4-3 in Comparative Example 1.

[0184] Comparative Example 3

[0185] This comparative example provides a method for short-range recovery of valuable metals from cobalt hydroxide feedstock, including:

[0186] S1: Same as S1 in Example 1.

[0187] S2: After the leaching tank G is full, feed the cobalt first-stage leaching solution in the leaching tank G into the filter press to obtain cobalt first-stage leaching residue and cobalt first-stage leaching solution.

[0188] S3: After passing through a precision filter, the cobalt leaching solution from the first stage yields a cobalt sulfate solution.

[0189] S4-1: The cobalt stage leaching residue and water are mixed at a mass ratio of 1:4 to obtain a first slurry with a concentration of 20wt%. The first slurry is transferred to the cobalt stage leaching tank, and concentrated sulfuric acid is added to adjust the pH of the solution in the cobalt stage leaching tank to 1.0. Then, ammonium sulfite (the amount of ammonium sulfite is 1.4 times the theoretical amount) is added to carry out cobalt stage leaching. When the cobalt stage leaching reaches the reaction endpoint, the mixture is filtered to obtain cobalt stage leaching residue and cobalt stage leaching solution.

[0190] S4-2: The cobalt stage leaching solution is pumped to the iron and aluminum removal tank, heated to 70°C, and calcium carbonate solution is added for pH adjustment. When the pH of the solution reaches 3.5-4.0, the addition of calcium carbonate is stopped. After filtration by a filter press, iron and aluminum slag and iron and aluminum removal liquid are obtained.

[0191] S4-3: Transfer the liquid after iron and aluminum removal to the copper removal reaction tank, add iron powder (the amount of iron powder added is 0.7 times the theoretical amount) to the copper removal reaction tank to replace the copper in the liquid after iron and aluminum removal; after the replacement is completed, pass it through the copper removal filter press to obtain sponge copper and copper removal liquid.

[0192] Test case

[0193] The main metal ion content of the cobalt leaching solution in Examples 1-7 and Comparative Examples 1-3, the reaction tank temperature of the cobalt leaching tank A, the main component composition of the cobalt leaching residue, the slag ratio of the cobalt leaching residue, the main component composition of the iron-aluminum slag, the amount of cobalt slag per ton (t / t), and the production cycle were compared. The results are shown in Tables 2 to 4.

[0194] Wherein, slag rate = (mass of cobalt leaching residue from cobalt stage 1 / mass of cobalt hydroxide raw material) × 100%;

[0195] "Quantity of cobalt slag per ton" refers to the mass of iron-aluminum slag obtained by inputting cobalt hydroxide raw material containing 1 ton of metallic cobalt. The mass unit of iron-aluminum slag is also ton. For example, if the cobalt metal content in the cobalt hydroxide raw material is 40wt%, then 2.5t of cobalt hydroxide raw material is required to obtain 1 ton of cobalt metal. Accordingly, "quantity of cobalt slag per ton" refers to the mass of iron-aluminum slag obtained by inputting 2.5t of cobalt hydroxide raw material.

[0196] "Production cycle" refers to the time from the start of cobalt hydroxide input to the production of iron-aluminum slag.

[0197] Table 2. Main metal ion content and reaction tank temperature of cobalt stage 1 leaching solution

[0198]

[0199]

[0200] Table 3. Main components and slag ratio of cobalt stage leaching residue.

[0201] Cobalt leaching residue Co,% Mn,% Fe,% Cu,% Slag ratio, % Example 1 12.0 5.2 2.45 1.59 10.3 Example 2 10.5 4.8 2.42 1.58 10.2 Example 3 11.2 5.0 2.38 1.60 10.4 Example 4 15.2 3.2 1.98 1.23 14.3 Example 5 16.4 2.8 1.65 0.89 15.3 Example 6 17.5 2.1 1.73 0.78 16.2 Example 7 18.3 2.9 1.59 0.83 15.9 Comparative Example 1 20.0 1.3 1.03 0.21 19.8 Comparative Example 2 23.0 1.6 1.12 0.26 18.6 Comparative Example 3 22.0 1.9 1.06 0.32 18.9

[0202] Table 4. Main components of iron-aluminum slag, amount of cobalt slag per ton, and production cycle.

[0203]

[0204]

[0205] As can be seen from Tables 2-4, the methods provided in Examples 1-7 of the present invention have a higher metal ion leaching rate than the methods provided in Comparative Examples 1-3, and the cobalt recovery rate is also higher.

[0206] As can be seen from Examples 1 and 4, dividing the cobalt leaching solution into cobalt leaching solution M and cobalt leaching solution N is more conducive to cobalt recovery.

[0207] As can be seen from Examples 1 and 5-7, different methods of cobalt leaching can affect the leaching rate of metal ions and the recovery rate of cobalt.

[0208] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for short-range recovery of valuable metals from cobalt hydroxide feedstock, characterized in that, Includes the following steps: The cobalt hydroxide slurry formed from cobalt hydroxide raw material is subjected to cobalt-first leaching with concentrated sulfuric acid to obtain cobalt-first leaching solution. The cobalt-1 leaching solution is subjected to solid-liquid separation to obtain cobalt-1 leaching residue and cobalt-1 leaching solution; The cobalt leaching residue is pulped to obtain a first slurry; the first slurry is then subjected to cobalt second-stage leaching with an oxidant and concentrated sulfuric acid, followed by the addition of ammonium bicarbonate to adjust the pH value, and solid-liquid separation to obtain iron-aluminum slag and iron-aluminum-removed liquid; copper in the iron-aluminum-removed liquid is replaced with iron powder or manganese powder, and solid-liquid separation is performed to obtain copper and copper-removed liquid.

2. The method according to claim 1, characterized in that, The first stage of cobalt leaching includes a first acid leaching of the cobalt hydroxide slurry with concentrated sulfuric acid to obtain a first acid leaching solution; and a second acid leaching of the first acid leaching solution by adding new cobalt hydroxide slurry to obtain the first stage of cobalt leaching solution. The pH value of the first acid leaching is 1.0 to 2.5, and the first acid leaching time is ≥1 hour; The pH value of the second acid leaching is 3.5 to 5.5, and the second acid leaching time is ≥1 hour.

3. The method according to claim 2, characterized in that, The first acid leaching includes the first acid leaching stage A, the first acid leaching stage B, and the first acid leaching stage C; The pH value of the first acid leaching stage A is 1.0 to 1.5, the pH value of the first acid leaching stage B is 1.5 to 2.0, and the pH value of the first acid leaching stage C is 2.0 to 2.

5.

4. The method according to claim 2, characterized in that, The second acid leaching includes the second acid leaching stage A, the second acid leaching stage B, the second acid leaching stage C, and the second acid leaching stage D. The pH value of the second acid leaching stage A is 3.5-4.0, the pH value of the second acid leaching stage B is 4.0-4.5, the pH value of the second acid leaching stage C is 4.5-5.0, and the pH value of the second acid leaching stage D is 5.0-5.

5.

5. The method according to claim 1, characterized in that, The solid-liquid separation of the cobalt leaching solution includes dividing the cobalt leaching solution into cobalt leaching solution M and cobalt leaching solution N in a mass ratio of 1:2 to 1:3.

5. The cobalt leaching solution M is subjected to solid-liquid separation to obtain cobalt leaching residue M1 and cobalt leaching solution M2. The cobalt-first leaching solution N is subjected to solid-liquid separation to obtain cobalt-first leaching residue N1 and cobalt-first leaching solution N2; Wherein, the cobalt first-stage leaching residue M1 is used to prepare a pulp to obtain the first pulp; the cobalt first-stage leaching solution M2 is used to obtain a cobalt sulfate solution; Preferably, the concentration of the first slurry is 15wt% to 20wt%.

6. The method according to claim 1, characterized in that, The cobalt two-stage leaching process includes: adding concentrated sulfuric acid to the first slurry to adjust the pH value to 0.5-1.5, followed by adding an oxidant for reductive leaching; The amount of oxidant used is 1.2 to 1.5 times the theoretical amount; Preferably, after reduction leaching, ammonium bicarbonate is added to adjust the pH value to 3.0–4.

5.

7. The method according to claim 1, characterized in that, The amount of iron powder or manganese powder used is 0.8 to 1.2 times the theoretical amount.

8. The method according to claim 1, characterized in that, The copper-removed solution is returned to the first acid leaching stage A for recycling. Preferably, the mass ratio of the copper-removed liquid to the cobalt hydroxide slurry used for the first stage of cobalt leaching is 1:10 to 3:

10.

9. The method according to claim 5, characterized in that, The cobalt leaching residue N1 is pulped to obtain a second pulp; concentrated sulfuric acid is added to the second pulp to adjust the pH value to 0.5-1.5, and then ammonium sulfite is added for reduction leaching to obtain a reduction leaching solution; Preferably, the concentration of the second slurry is 15wt% to 20wt%; Preferably, the amount of ammonium sulfite added is 0.8 to 1.1 times the theoretical amount; Preferably, the reducing leachate is used for recycling in the first acid leaching stage A; Preferably, the mass ratio of the reducing leachate to the cobalt hydroxide slurry used for cobalt stage leaching is 4:10 to 6:

10.

10. The method according to claim 1, characterized in that, The cobalt hydroxide raw material contains ≥30% cobalt and ≤0.5wt% Al.

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