Selective leaching method of alkaline hydroxide ore

Abstract

The invention relates to the technical field of hydrometallurgy, in particular to a selective leaching method of alkaline hydroxide ore, which comprises the following steps: fully mixing the alkaline hydroxide ore, an ammonium leaching agent and water to react, and obtaining reaction slurry after the reaction is finished; carrying out solid-liquid separation on the obtained reaction slurry to obtain a leaching solution I and a leaching residue I, and collecting the leaching solution I; s3, mixing the leached residues I with water for slurrying to obtain leached residue slurry; and S4, an acid leaching agent and a reducing agent are added into the leaching residue slurry under the conditions of heating and stirring, solid-liquid separation is conducted after full reaction, second leaching liquid and second leaching residues are obtained, and the second leaching liquid is collected. According to the leaching method, the follow-up impurity removal difficulty can be reduced while the leaching rate of cobalt, manganese and nickel of the alkaline hydroxide ore can be increased.

Description

Technical Field

[0001] This invention relates to the field of hydrometallurgical technology, and in particular to a selective leaching method for alkaline hydroxide ores. Background Technology

[0002] Cobalt, manganese, and nickel are indispensable strategic metals for high-tech industries, playing a crucial role in fields such as high-temperature alloys, hard alloys, and the electronics industry. Among them, cobalt, as a key component of core materials such as lithium-ion batteries, faces a particularly severe supply-demand imbalance. To alleviate this imbalance, the efficient extraction and utilization of cobalt resources found in hydroxide ores has become a key approach. However, cobalt in these ores often coexists with metals such as manganese, nickel, and copper, resulting in a complex composition. Traditional leaching processes suffer from poor selectivity, low recovery rates, and high reagent consumption, hindering the effective utilization of these resources.

[0003] Currently, commonly used industrial mineral and metal leaching methods mainly include acidic systems (e.g., H₂SO₄—H₂O), ammoniacal systems (e.g., NH₃—(NH₄)₂SO₄—H₂O), and alkaline systems (e.g., NaOH—H₂O). Acidic leaching processes easily dissolve all impurities such as calcium, magnesium, iron, and aluminum, leading to complex subsequent impurity removal processes and high costs. Ammoniacal leaching processes require excellent sealing, tail gas absorption, and ammonia recovery systems, resulting in complex processes and increased production costs. Furthermore, ammonia is volatile, causing leaching agent loss and environmental pollution, increasing raw material costs and the difficulty of managing liquid ammonia safely. Alkaline leaching processes are only suitable for amphoteric metal minerals and require the use of high-concentration strong alkalis (such as caustic soda), limiting their applicability.

[0004] In summary, existing leaching processes struggle to balance selectivity, economic efficiency, and environmental friendliness when treating alkaline hydroxide ores, necessitating the development of a novel and highly efficient selective leaching technology. Therefore, this paper proposes a selective leaching method for alkaline hydroxide ores, aiming to efficiently separate and recover valuable metals such as cobalt. This method is of significant practical importance for enhancing strategic resource supply capacity and supporting the independent development of high-tech industries. Summary of the Invention

[0005] This invention provides a selective leaching method for alkaline hydroxide ores, which improves the leaching rates of cobalt, manganese, and nickel while reducing the difficulty of subsequent impurity removal.

[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: A selective leaching method for alkaline hydroxide ores, comprising the following steps: First stage of leaching process: S1. Thoroughly mix and react the alkaline hydroxide ore, ammonium leaching agent, and water. After the reaction is complete, a reaction slurry is obtained. S2. Perform solid-liquid separation on the obtained reaction slurry to obtain leachate 1 and leach residue 1, and collect leachate 1; Second leaching process: S3. Mix the leaching residue 1 with water to make a slurry, and obtain the leaching residue slurry; S4. Under heating and stirring conditions, add acid leaching agent and reducing agent to the leachate slurry. After the reaction is complete, perform solid-liquid separation to obtain leachate 2 and leachate 2. Collect leachate 2.

[0007] In some embodiments, the alkaline hydroxide ore includes at least one metallic element selected from cobalt, manganese, and nickel; wherein, based on the total mass of the alkaline hydroxide ore, the mass fraction of cobalt is 5-25%; the mass fraction of manganese is 10-40%; and the mass fraction of nickel is 5-30%.

[0008] In some embodiments, in step S1, before the alkaline hydroxide ore is mixed with ammonium leaching agent and water, the alkaline hydroxide ore is first crushed and then passed through a 100-200 mesh sieve.

[0009] In some embodiments, the mass ratio of the alkaline hydroxide ore, ammonium leaching agent, and water is 1:(2.5-8):(3-12).

[0010] In some embodiments, the ammonium leaching agent is a solution containing ammonium ions.

[0011] In some embodiments, the ammonium leaching agent is at least one selected from ammonium chloride, ammonium sulfate, ammonium carbonate, ammonium bicarbonate, ammonium nitrate, ammonium phosphate, ammonium hydrogen phosphate, and ammonium dihydrogen phosphate.

[0012] In some embodiments, in step S3, the mass ratio of the leaching residue to water is 1:(3-10).

[0013] In some embodiments, in step S4, the heating temperature is 30-90°C, the stirring speed is 300-600 rpm, and the reaction time is 60-480 min; And / or, the mass ratio of the leaching residue, acid leaching agent and reducing agent is 1:(0.09-0.18):(0.002-0.005).

[0014] In some embodiments, the acid leaching agent is at least one selected from sulfuric acid, hydrochloric acid, nitric acid, and citric acid; And / or, the reducing agent is at least one of ammonium sulfite, sodium sulfite, sodium bisulfite, and ferrous sulfate.

[0015] In some embodiments, step S2, before solid-liquid separation of the reaction slurry, further includes the following step: Under the conditions of heating and stirring the reaction slurry, an active additive is added to the reaction slurry, and after the reaction is completed, the slurry is subjected to solid-liquid separation.

[0016] In some embodiments, the reaction conditions for adding the active additive to the reaction slurry are: heating temperature of 30-100°C, stirring speed of 300-600 rpm, and reaction time of 60-480 min. And / or, the mass ratio of the alkaline hydroxide mineral to the active additive is 1:(0.0005-0.003); And / or, the active additive is at least one of TW-20, sodium hexametaphosphate, polyvinylpyrrolidone, ethylenediaminetetraacetic acid, and sodium dodecyl sulfonate.

[0017] The beneficial effects of this invention are: 1. This invention employs a two-stage leaching process, namely ammonium leaching in the first stage and acid leaching and reduction in the second stage, to achieve a total leaching rate of Co, Ni, and Mn of up to 99% or more, thereby improving the total leaching rate of Co, Ni, and Mn.

[0018] 2. This invention achieves selective leaching of Co, Ni and Mn by employing a two-stage leaching process, reducing the difficulty of subsequent impurity removal. Detailed Implementation

[0019] To make the objectives, technical solutions, and technical effects of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are described clearly and completely. The embodiments described below are some embodiments of the present invention, but not all embodiments. All other embodiments obtained by those skilled in the art in conjunction with the embodiments of the present invention without creative effort are within the scope of protection of the present invention. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall be followed; where the manufacturers of reagents or instruments are not specified, they are all conventional products that can be purchased commercially.

[0020] In the description of this invention, the term "and / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0021] In the description of this invention, "at least one" means one or more, and "more than one" means two or more. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single or multiple items. For example, "at least one of a, b, or c", or "at least one of a, b, and c", can both mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can each be single or multiple.

[0022] It should be understood that the weights of the relevant components mentioned in the embodiments of this invention can refer not only to the specific content of each component, but also to the proportional relationship between the weights of the components. Therefore, any scaling up or down of the content of the relevant components according to the embodiments of this invention is within the scope of this invention. Specifically, the weights mentioned in the embodiments of this invention can be well-known units of mass in the chemical industry, such as μg, mg, g, and kg.

[0023] Furthermore, unless the context explicitly uses it otherwise, the singular form of a word should be understood as including the plural form of that word. The terms "comprising" or "having" are intended to specify the presence of a feature, quantity, step, operation, element, part, or combination thereof, but are not intended to exclude the presence or possible addition of one or more other features, quantities, steps, operations, elements, parts, or combinations thereof.

[0024] The present invention provides a selective leaching method for alkaline hydroxide ores, comprising the following steps: First stage of leaching process: S1. Thoroughly mix and react the alkaline hydroxide ore, ammonium leaching agent, and water. After the reaction is complete, a reaction slurry is obtained. S2. Perform solid-liquid separation on the obtained reaction slurry to obtain leachate 1 and leach residue 1, and collect leachate 1; Second leaching process: S3. Mix the leaching residue 1 with water to make a slurry, and obtain the leaching residue slurry; S4. Under heating and stirring conditions, add acid leaching agent and reducing agent to the leachate slurry. After the reaction is complete, perform solid-liquid separation to obtain leachate 2 and leachate 2. Collect leachate 2.

[0025] This invention employs a two-stage leaching process: a first stage of ammonium leaching followed by a second stage of acid leaching and reduction. This achieves selective leaching of Co, Ni, and Mn, increases the total leaching rate of Co, Ni, and Mn, and reduces the difficulty of subsequent impurity removal. The first stage utilizes ammonium leaching agent to preferentially dissolve valuable metals such as cobalt, nickel, and manganese, which exist in ionic or weakly bound states in alkaline hydroxides, achieving preliminary and efficient extraction. The second stage uses acid leaching agent combined with a reducing agent on the leaching residue to further recover residual metals, significantly improving the overall leaching rate of cobalt, manganese, and nickel.

[0026] The first stage uses a weakly alkaline or near-neutral ammonium salt system for selective leaching, which avoids the large-scale dissolution of impurity metals such as aluminum, iron, and magnesium under strong acid conditions. It effectively inhibits the entry of impurity ions into the first leaching solution, resulting in high enrichment of target metals (Co, Ni, Mn) and low impurity content in the first leaching solution. It can be directly used for subsequent recovery processes such as precipitation, extraction, or electrowinning, reducing the consumption of impurity removal reagents and impurity removal process steps.

[0027] In the first leaching process, the ammonium leaching agent reacts with the hydroxide ore. The hydroxide ore slightly dissolves in the aqueous solution and ionizes into metal ions and hydroxide ions. Then, the hydroxide ions combine with the ammonium ions ionized from the ammonium leaching agent to form ammonia and water, while the metal ions combine with free ammonia to form metal-ammonia complex ions. Because the dissolved metal ions are complexed by ammonia, their concentration decreases, thereby promoting the continuous dissolution and ionization of the hydroxide ore into metal ions and hydroxide ions, ensuring the continuous progress of the ammonia leaching reaction. In the first leaching process, most of the cobalt, manganese, and nickel metals are leached into the first leaching solution in the form of complex ions. A small amount of unleached cobalt, manganese, and nickel metals remain in the first leaching residue and undergo the second leaching process. The first leaching solution has a low impurity content, containing only a small amount of calcium and magnesium impurities and no iron or aluminum impurities.

[0028] In the second leaching process, the acid leaching agent reacts with various metal compounds in the leaching residue to generate a soluble metal salt solution, and the metal elements enter the leaching solution in ionic form. The presence of a reducing agent can reduce sparingly soluble high-valence metal compounds to divalent metal compounds, which then react with the acid leaching agent to form a soluble metal salt solution.

[0029] In some embodiments, the alkaline hydroxide ore includes at least one metallic element selected from cobalt, manganese, and nickel. Specifically, based on the total mass of the alkaline hydroxide ore, the mass fraction of cobalt is 5-25%; the mass fraction of manganese is 10-40%; and the mass fraction of nickel is 5-30%.

[0030] In some embodiments, the total mass of cobalt, manganese, and nickel metal elements in leachate one is equal to that in (NH4) + The mass ratio of ) is 1:(3-10).

[0031] In some embodiments, in step S1, before the alkaline hydroxide ore is mixed with ammonium leaching agent and water, the alkaline hydroxide ore is first crushed and then passed through a 100-200 mesh sieve.

[0032] Crushing and sieving alkaline hydroxide ore through a 100-200 mesh sieve before mixing can significantly increase the specific surface area of ​​mineral particles, promote effective contact with ammonium leaching agent, accelerate the first-stage leaching reaction kinetics, and improve the leaching rate and extraction rate of target metals such as cobalt, nickel, and manganese under mild conditions. At the same time, fine particle size helps to form a uniform slurry, reduce local encapsulation or unreacted nuclei, and improve reaction uniformity, thereby achieving efficient leaching without introducing strong acid conditions and helping to maintain a low level of impurity dissolution.

[0033] In some embodiments, the mass ratio of the alkaline hydroxide ore, ammonium leaching agent, and water is 1:(2.5-8):(3-12).

[0034] By controlling the mass ratio of alkaline hydroxide ore, ammonium leaching agent, and water to 1:(2.5-8):(3-12), sufficient leaching agent concentration is ensured to drive the reaction while maintaining suitable slurry concentration and fluidity. This ratio range guarantees the effective complexation and dissolution of target metals (cobalt, nickel, manganese, etc.) by ammonium ions, while avoiding increased costs or non-selective dissolution of impurities (such as Al and Fe) due to excessive leaching agent. It also facilitates subsequent solid-liquid separation operations, thereby improving the leaching rates of cobalt, nickel, and manganese while stabilizing the quality of the leachate and reducing the difficulty of subsequent purification.

[0035] In some embodiments, the ammonium leaching agent is a solution containing ammonium ions. Specifically, the ammonium leaching agent is a solution containing NH4+. + The solution, using NH4 + Under near-neutral or weakly alkaline conditions, it forms stable, soluble ammonia complexes with ions such as cobalt, nickel, and manganese (e.g., [Co(NH3)6]). 2+ This system leverages the properties of [specific components] to achieve selective leaching of target metals. It avoids the severe corrosion of minerals by strong acid environments, significantly inhibits the entry of impurities such as Fe, Al, and Mg, fundamentally reducing the impurity load of the leachate and facilitating the subsequent direct recovery of Co, Ni, and Mn.

[0036] In some embodiments, the ammonium leaching agent is at least one selected from ammonium chloride, ammonium sulfate, ammonium carbonate, ammonium bicarbonate, ammonium nitrate, ammonium phosphate, ammonium hydrogen phosphate, and ammonium dihydrogen phosphate.

[0037] Specific ammonium salts such as ammonium chloride, ammonium sulfate, ammonium carbonate, ammonium bicarbonate, ammonium nitrate, ammonium phosphate, ammonium hydrogen phosphate, and ammonium dihydrogen phosphate were selected as leaching agents. These reagents can all provide sufficient NH4. +It also forms a corresponding anionic environment, in which ammonium sulfate, ammonium bicarbonate and other substances have a certain buffering capacity, which helps to maintain the pH stability of the system and prevent local acidification from causing the dissolution of impurities.

[0038] In some embodiments, in step S3, the mass ratio of the leaching residue to water is 1:(3-10). By controlling the mass ratio of the leaching residue to water to 1:(3-10), it is ensured that the slurry before the second stage of acid leaching has suitable solid content and fluidity. This ratio facilitates the full diffusion of the acid leaching agent and reducing agent to the surface of solid particles, improving reaction efficiency; at the same time, it avoids excessively high solid content leading to increased mass transfer resistance or excessively low solid content causing reagent waste. A reasonable slurry concentration helps to achieve efficient leaching of residual metals such as manganese with lower acid consumption, improves the overall recovery rate, reduces waste acid emissions, and reduces environmental pressure.

[0039] In some embodiments, in step S4, the heating temperature is 30-90°C, the stirring speed is 300-600 rpm, and the reaction time is 60-480 min; And / or, the mass ratio of the leaching residue, acid leaching agent and reducing agent is 1:0.09-0.18:0.002-0.005.

[0040] This invention controls the temperature of the second-stage leaching process to 30-90°C, a temperature range sufficient to activate the reaction rate between the acid and the mineral, thus promoting the growth of high-valence manganese (such as Mn). 4+ The reduction and dissolution under the action of the reducing agent significantly improves the leaching rate of manganese; at the same time, it avoids the violent dissolution of impurity metals such as iron and aluminum or the generation of a large amount of acid mist caused by excessively high temperature (>90℃), thereby maintaining the impurity concentration in the second leaching solution at a controllable level and reducing the difficulty of subsequent impurity removal.

[0041] Stirring at 300-600 rpm ensures rapid and uniform distribution of the acid leaching agent and reducing agent in the slurry, effectively breaking the diffusion layer at the solid-liquid interface, improving the contact efficiency between the reagent and the leaching residue particles, and preventing local concentrations from being too high or too low. This not only improves the reaction rate and metal recovery rate, but also reduces reagent waste and side reactions, which is conducive to obtaining a leachate with stable composition.

[0042] The amount of acid leaching agent used is 0.09-0.18 times that of leaching residue one. This ratio is sufficient to provide enough hydrogen ions to dissolve the reduced manganese and other metal hydroxides, ensuring a high manganese leaching rate. At the same time, it avoids excessive acid, which would cause a large amount of impurities such as iron, aluminum, and magnesium to dissolve. This effectively inhibits impurities from entering leaching solution two, reduces the alkali consumption and residue volume in subsequent neutralization and impurity removal, and alleviates environmental pressure.

[0043] The dosage of reducing agent is controlled at 0.002-0.05 times that of leaching residue one. This trace addition can effectively reduce the high-valent manganese in the residue to soluble Mn.2+ It greatly improves the leaching efficiency of manganese; if the dosage is too low, the reduction will be incomplete and the recovery rate will be affected; if the dosage is too high, it will not only increase the cost, but may also lead to side reactions or introduce too many anionic impurities.

[0044] By controlling the mass ratio of leaching residue 1: acid leaching agent: reducing agent to 1: (0.09-0.18): (0.002-0.05), the acid is used for dissolution, and the reducing agent is used for activation of insoluble components. The two work synergistically in this ratio, which can achieve deep recovery of residual cobalt, nickel and manganese in the residue with low reagent consumption, improve resource utilization, and maintain the purity of the solution, which is conducive to reducing the difficulty of subsequent metal separation.

[0045] In some embodiments, the acid leaching agent is at least one selected from sulfuric acid, hydrochloric acid, nitric acid, and citric acid; And / or, the reducing agent is at least one of ammonium sulfite, sodium sulfite, sodium bisulfite, and ferrous sulfate.

[0046] In some embodiments, step S2, before solid-liquid separation of the reaction slurry, further includes the following step: Under the conditions of heating and stirring the reaction slurry, an active additive is added to the reaction slurry, and after the reaction is completed, the slurry is subjected to solid-liquid separation.

[0047] Active additives can reduce the liquid-solid interfacial tension and enhance the ability of ammonium ions to penetrate into mineral microcracks.

[0048] Active additives do not participate in the chemical reaction during the ammonium leaching process; instead, they enhance reaction efficiency through physicochemical effects such as altering interfacial properties. The principles are as follows: First, the active additives adsorb onto the hydrophobic surface of the mineral, making it hydrophilic and promoting the wetting of the mineral by the ammonium salt, allowing it to penetrate into micropores and cracks. Second, the active additives significantly reduce the surface tension of the solution, expanding the reaction area. Third, the additives adsorb onto the particle surface, forming a protective film, and electrostatic repulsion separates the particles, maintaining a highly dispersed state and preventing particle aggregation.

[0049] The purpose of mixing the ammonium leaching agent with the hydroxide ore before adding the active additive is as follows: First, to prioritize the initiation of the main reaction; second, since the active additive targets the solid-liquid interface, the addition of the additive after the slurry is formed allows for more efficient diffusion and adsorption onto the existing interface, enabling it to exert its effect directly; third, to avoid competitive adsorption with ammonia molecules, allowing ammonia molecules to initially interact with the mineral surface and occupy its chemical adsorption sites, while the subsequently added active additive primarily acts on the physical adsorption sites, resulting in a synergistic effect without interference.

[0050] In some embodiments, the reaction conditions for adding the active additive to the reaction slurry are: heating temperature of 30-100°C, stirring speed of 300-600 rpm, and reaction time of 60-480 min. And / or, the mass ratio of the alkaline hydroxide mineral to the active additive is 1:(0.0005-0.003); And / or, the active additive is at least one of TW-20, sodium hexametaphosphate, polyvinylpyrrolidone, ethylenediaminetetraacetic acid, and sodium dodecyl sulfonate.

[0051] By controlling the reaction conditions when adding the active additive within the above-mentioned range, the interfacial regulation and dispersion effects of the active additive can be fully utilized, significantly improving the reaction efficiency and uniformity of the first stage of ammonium leaching. Specifically, controlling the heating temperature between 30-100℃ is beneficial for enhancing molecular thermal motion, promoting the diffusion of ammonium ions and active additives to the surface of mineral particles and microporous structures, accelerating the complexation and dissolution of target metals (Co, Ni, Mn), and increasing the leaching rate and total leaching rate. At the same time, this temperature range avoids the decomposition of ammonium salts or the non-selective dissolution of impurity metals (such as Fe, Al) caused by high temperatures, maintaining the selectivity of the leaching system.

[0052] The stirring speed is maintained at 300-600 rpm to ensure that the slurry is fully turbulent, so that the active additives are evenly dispersed in the solid-liquid system, effectively preventing the agglomeration of mineral particles and enhancing the solid-liquid interface.

[0053] The reaction time is set to 60-480 min, which provides sufficient time for the active additive to act, ensuring that its wetting, dispersion and complexation promotion effects on the mineral surface are fully completed. It is especially suitable for hydroxide minerals with dense structure or passivated surface, and significantly improves the leaching rate of insoluble components.

[0054] In summary, the synergistic control of the reaction conditions maximizes the effect of the active additives, significantly improves the leaching efficiency of cobalt, nickel, and manganese without compromising selectivity, and helps to obtain a clear and stable leachate, reducing the difficulty of subsequent solid-liquid separation and impurity removal.

[0055] By limiting the addition of active additives to 0.05%-0.3% of the mineral content, this ratio range ensures sufficient additive molecules to cover the surface of mineral particles, effectively inhibiting the agglomeration and colloidal phenomena of fine hydroxides, improving the rheological properties of the slurry, and promoting ammonium ion penetration and metal dissolution, thereby increasing the leaching rates of cobalt, nickel, and manganese. At the same time, it avoids excessive additive addition, which could lead to increased costs, excessive foaming, or the introduction of too many organic / inorganic impurity ions, affecting subsequent solution purification. Especially when treating fine-grained minerals with high specific surface areas (such as those passing through a 100-200 mesh sieve), this low addition amount can achieve good dispersion and wetting effects, significantly improving the clarity and purity of the leachate, reducing the interference of colloidal impurities on subsequent extraction or precipitation processes, and effectively reducing the difficulty of impurity removal.

[0056] TW-20 (Tween-20), sodium hexametaphosphate, polyvinylpyrrolidone (PVP), ethylenediaminetetraacetic acid (EDTA), and sodium dodecyl sulfonate were selected as active additives, all of which have good surface activity or complexing ability and can specifically improve the reaction environment of the first stage ammonium leaching process. TW-20 and sodium dodecyl sulfonate are nonionic or anionic surfactants that can significantly reduce the surface tension of the slurry, enhance the wetting and penetration ability of the leaching agent on the mineral surface, break up particle agglomeration, and increase the reaction contact area. Sodium hexametaphosphate is a highly efficient dispersant that can be adsorbed on the mineral surface, generating electrostatic repulsion, preventing fine particle flocculation, maintaining slurry stability, and facilitating solid-liquid separation. Polyvinylpyrrolidone (PVP) has excellent dispersing and stabilizing effects, preventing the redeposition of metal hydroxides and maintaining the soluble state of the target metal in the solution. Ethylenediaminetetraacetic acid (EDTA) is a strong complexing agent that can form stable soluble complexes with cobalt, nickel, and manganese ions, directly promoting their dissolution and inhibiting hydrolysis and precipitation. The above-mentioned additives, used alone or in combination, can significantly improve the leaching rate of cobalt, nickel, and manganese under mild conditions. At the same time, by improving the slurry properties and inhibiting the colloidal dissolution of impurities, they can improve the clarity and purity of the leachate, thereby effectively reducing the load and complexity of subsequent impurity removal processes.

[0057] To enable those skilled in the art to clearly understand the above-described implementation details and operations of the present invention, and to demonstrate the significant advancements in the performance of the embodiments of the present invention, the following examples illustrate the above technical solutions.

[0058] Table 1 shows the metal composition of one type of alkaline hydroxide ore. Unless otherwise specified, the metal composition of the alkaline hydroxide ore used in the following examples or comparative examples is shown in Table 1.

[0059] Table 1: Example 1 A selective leaching method for alkaline hydroxide ores includes the following steps: First stage of leaching process: S1. The alkaline hydroxide ore is crushed and passed through a 200-mesh sieve; then the sieved alkaline hydroxide ore is mixed with ammonium sulfate and water at a mass ratio of 1:8:12 and allowed to react fully to obtain a reaction slurry. S2: Sodium hexametaphosphate was added to the reaction slurry obtained in step S1 under heating and stirring conditions. The reaction temperature was 60℃, the reaction time was 180 min, and the stirring speed was 400 rpm. After the reaction was completed, solid-liquid separation was performed to obtain leachate one and leach residue one. The total mass of cobalt, manganese, and nickel metal elements in the leachate was equal to that in NH4. + The mass ratio is 1:10.

[0060] Second leaching process: S3: Mix leaching residue 1 and water at a mass ratio of 1:3 to form a slurry, and obtain leaching residue slurry; S4: Under heating and stirring conditions, hydrochloric acid and sodium sulfite are added to the leaching residue slurry for the second stage leaching reaction. The reaction temperature is 40℃, the reaction time is 90min, and the stirring speed is 500rpm. The mass ratio of leaching residue one: hydrochloric acid: sodium sulfite is 1:0.18:0.05. After the reaction is completed, solid-liquid separation is performed to obtain leaching solution two and leaching residue two.

[0061] Example 2 A selective leaching method for alkaline hydroxide ores includes the following steps: First stage of leaching process: S1. The alkaline hydroxide ore is crushed and passed through a 200-mesh sieve; then the sieved alkaline hydroxide ore is mixed with ammonium chloride and water at a mass ratio of 1:7:10 and allowed to react fully to obtain a reaction slurry. S2: Sodium dodecyl sulfonate was added to the reaction slurry obtained in step S1 under heating and stirring conditions. The reaction temperature was 50℃, the reaction time was 90 min, and the stirring speed was 450 rpm. After the reaction was completed, solid-liquid separation was performed to obtain leachate one and leach residue one. The total mass of cobalt, manganese, and nickel metal elements in the leachate was equal to that in NH4. + The mass ratio is 1:8.

[0062] Second leaching process: S3: Mix leaching residue 1 and water at a mass ratio of 1:8 to form a slurry, and obtain leaching residue slurry; S4: Under heating and stirring conditions, sulfuric acid and sodium bisulfite are added to the leaching residue slurry to carry out the second stage leaching reaction. The reaction temperature is 30℃, the reaction time is 120min, and the stirring speed is 400rpm. The mass ratio of leaching residue one: hydrochloric acid: sodium bisulfite is 1:0.13:0.004. After the reaction is completed, solid-liquid separation is carried out to obtain leaching solution two and leaching residue two.

[0063] Example 3 A selective leaching method for alkaline hydroxide ores includes the following steps: First stage of leaching process: S1. The alkaline hydroxide ore is crushed and passed through a 200-mesh sieve; then the sieved alkaline hydroxide ore is mixed with ammonium carbonate and water at a mass ratio of 1:4:11 and allowed to react fully to obtain a reaction slurry. S2: Polyvinylpyrrolidone was added to the reaction slurry obtained in step S1 under heating and stirring conditions. The reaction temperature was 55℃, the reaction time was 150 min, and the stirring speed was 350 rpm. After the reaction was completed, solid-liquid separation was performed to obtain leaching solution one and leaching residue one. The total mass of cobalt, manganese, and nickel metal elements in the leaching solution was equal to that in NH4+. + The mass ratio is 1:5.

[0064] Second leaching process: S3: Mix the leaching residue and water at a mass ratio of 1:7 to form a slurry, and obtain the leaching residue slurry. S4: Under heating and stirring conditions, nitric acid and ammonium sulfite were added to the leaching residue slurry for the second stage leaching reaction. The reaction temperature was 35℃, the reaction time was 60 min, and the stirring speed was 550 rpm. The mass ratio of leaching residue one: hydrochloric acid: sodium sulfite was 1:0.15:0.008. After the reaction was completed, solid-liquid separation was performed to obtain leaching solution two and leaching residue two.

[0065] Example 4 The difference between Example 4 and Example 1 is that sodium hexametaphosphate is not added to the reaction slurry in Example 4. The reaction slurry obtained in step S1 is directly subjected to solid-liquid separation to obtain leachate 1 and leach residue 1. Other process steps are the same as in Example 1.

[0066] Example 5 The difference between Example 5 and Example 1 is that the reaction temperature in step S2 of Example 5 is 10°C, while the other conditions are the same as in Example 1.

[0067] Example 6 The difference between Example 6 and Example 1 is that the reaction temperature in step S2 of Example 6 is 120°C, while the other conditions are the same as in Example 1.

[0068] Example 7 The difference between Example 7 and Example 1 is that the mass ratio of alkaline hydroxide mineral to sodium hexametaphosphate in Example 7 is 1:0.0002, while other conditions are the same as in Example 1.

[0069] Comparative Example 1 The difference between Comparative Example 1 and Example 1 is that in Comparative Example 1, the mass ratio of alkaline hydroxide mineral, ammonium sulfate and water is 1:2:2, and other conditions are the same as in Example 1.

[0070] Comparative Example 2 The difference between Comparative Example 2 and Example 1 is that in Comparative Example 2, the mass ratio of alkaline hydroxide mineral, ammonium sulfate and water is 1:9:15, and other conditions are the same as in Example 1.

[0071] Comparative Example 3 The difference between Comparative Example 3 and Example 1 is that in Comparative Example 3, the mass ratio of leaching residue 1: hydrochloric acid: sodium sulfite is 1:0.05:0.001, and other conditions are the same as in Example 1.

[0072] Comparative Example 4 The difference between Comparative Example 4 and Example 1 is that in Comparative Example 4, the mass ratio of leaching residue 1: hydrochloric acid: sodium sulfite is 1:0.2:0.08, and other conditions are the same as in Example 1.

[0073] Performance testing Leaching rate test method In this experiment, the precise content of metal elements in the raw materials and leachate was determined by inductively coupled plasma optical emission spectrometry (ICP-OES). The analyzed items were: Co, Mn, K, Na, Fe, Al, Ca, Mg, Cu, Zn, Ni, Pb, and Cd.

[0074] The leaching rate is calculated as follows: The leaching rate of raw material metal (M) is calculated based on the weight of metal elements in the filtrate.

[0075] M (%) = (C2×V2×100) / (W1×X1) (1) In formula (1): W1—Weight of the raw material sample, in grams; X1—Mass percentage of metal (M) in the raw material sample; V2—Volume of filtrate, in liters (L); C2 — Concentration of metal (M) ions in the filtrate, in g / L.

[0076] Table 2 records the relevant metal leaching rates in the first stage leaching process of Examples 1-8 and Comparative Examples 1-4, and the total metal leaching rate after combining the first stage leaching process and the second stage leaching process is also recorded in Table 2.

[0077] Table 2 As can be seen from Examples 1-7 in Table 2, especially Examples 1-3, the first leaching process can selectively leach large amounts of cobalt, manganese, and nickel metals with low impurity content, and even the leaching rate of impurities such as iron and aluminum is zero. The combination of the first leaching process and the second leaching process can greatly improve the total leaching rate of cobalt, nickel, and manganese metals, so that the total leaching rate can reach 99.87%, 99.71%, and 99.06% respectively, which is higher than other leaching methods.

[0078] A comparison between Example 1 and Example 4 shows that the addition of active additives can improve the leaching rate of cobalt, manganese and nickel metals without causing the dissolution and leaching of impurity metals. However, a comparison between Example 1 and Example 7 shows that when the amount of active additives added is too small, the leaching rate of cobalt, manganese and nickel metals will be reduced.

[0079] A comparison of Example 1 and Examples 5-6 shows that the reaction temperature of the first leaching process affects the leaching rate of cobalt, manganese, and nickel metals.

[0080] As can be seen from the comparison between Example 1 and Comparative Examples 1-2, when the amount of ammonium leaching agent added is too small, the selective leaching of cobalt, manganese and nickel metals will be greatly reduced, affecting the final total leaching rate. When the amount of ammonium leaching agent added is too large, it will lead to an increase in the leaching rate of impurities.

[0081] As can be seen from the comparison between Example 1 and Comparative Examples 3-4, when the amount of acid leaching agent and reducing agent added is too small, the leaching rate of cobalt, manganese and nickel metals will be greatly reduced. When the amount of acid leaching agent and reducing agent added reaches a certain proportion, the leaching rate of cobalt, manganese and nickel metals remains constant and it is difficult to continue to increase.

[0082] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. A selective leaching method for alkaline hydroxide minerals, characterized in that, Includes the following steps: First stage of leaching process: S1. Thoroughly mix and react the alkaline hydroxide ore, ammonium leaching agent, and water. After the reaction is complete, a reaction slurry is obtained. S2. Perform solid-liquid separation on the obtained reaction slurry to obtain leachate 1 and leach residue 1, and collect leachate 1; Second leaching process: S3. Mix the leaching residue 1 with water to make a slurry, and obtain the leaching residue slurry; S4. Under heating and stirring conditions, add acid leaching agent and reducing agent to the leachate slurry. After the reaction is complete, perform solid-liquid separation to obtain leachate 2 and leachate 2. Collect leachate 2.

2. The selective leaching method for alkaline hydroxide ore according to claim 1, characterized in that, The alkaline hydroxide ore includes at least one metallic element selected from cobalt, manganese, and nickel; wherein, based on the total mass of the alkaline hydroxide ore, the mass fraction of cobalt is 5-25%; the mass fraction of manganese is 10-40%; and the mass fraction of nickel is 5-30%.

3. The selective leaching method for alkaline hydroxide ores according to claim 1, characterized in that, In step S1, before the alkaline hydroxide ore is mixed with ammonium leaching agent and water, the alkaline hydroxide ore is crushed and then screened through a 100-200 mesh sieve.

4. The selective leaching method for alkaline hydroxide ore according to claim 1, characterized in that, The mass ratio of the alkaline hydroxide ore, ammonium leaching agent, and water is 1:(2.5-8):(3-12).

5. The selective leaching method for alkaline hydroxide ore according to claim 1, characterized in that, The ammonium leaching agent is a solution containing ammonium ions.

6. The selective leaching method for alkaline hydroxide ore according to claim 5, characterized in that, The ammonium leaching agent is at least one of ammonium chloride, ammonium sulfate, ammonium carbonate, ammonium bicarbonate, ammonium nitrate, ammonium phosphate, ammonium hydrogen phosphate, and ammonium dihydrogen phosphate.

7. The selective leaching method for alkaline hydroxide ores according to claim 1, characterized in that, In step S3, the mass ratio of the leaching residue to water is 1:(3-10).

8. The selective leaching method for alkaline hydroxide ore according to claim 1, characterized in that, In step S4, the heating temperature is 30-90℃, the stirring speed is 300-600rpm, and the reaction time is 60-480min; And / or, the mass ratio of the leaching residue, acid leaching agent and reducing agent is 1:(0.09-0.18):(0.002-0.05).

9. The selective leaching method for alkaline hydroxide ore according to claim 1, characterized in that, The acid leaching agent is at least one of sulfuric acid, hydrochloric acid, nitric acid, and citric acid; And / or, the reducing agent is at least one of ammonium sulfite, sodium sulfite, sodium bisulfite, and ferrous sulfate.

10. The selective leaching method for alkaline hydroxide ores according to any one of claims 1-9, characterized in that, In step S2, before solid-liquid separation of the reaction slurry, the following step is also included: Under the conditions of heating and stirring the reaction slurry, an active additive is added to the reaction slurry, and after the reaction is completed, the slurry is subjected to solid-liquid separation.

11. The selective leaching method for alkaline hydroxide ore according to claim 10, characterized in that, The reaction conditions for adding the active additive to the reaction slurry are: heating temperature of 30-100℃, stirring speed of 300-600rpm, and reaction time of 60-480min; And / or, the mass ratio of the alkaline hydroxide mineral to the active additive is 1:(0.0005-0.003); And / or, the active additive is at least one of TW-20, sodium hexametaphosphate, polyvinylpyrrolidone, ethylenediaminetetraacetic acid, and sodium dodecyl sulfonate.

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