MHP short-process nickel-cobalt-manganese purification liquid preparation technology

Abstract

The invention discloses an MHP short-process nickel-cobalt-manganese purification liquid preparation technology, and belongs to the technical field of hydrometallurgy. Comprising the following steps: drying a cobalt nickel hydroxide raw material; carrying out size mixing, reduction leaching and separation to obtain a primarily purified nickel-cobalt-manganese solution and manganese-containing slag; carrying out acidification leaching on the manganese-containing slag, and separating to obtain manganese-silicon slag and a nickel-containing pickling solution; adding a neutralizing agent into the primarily purified nickel-cobalt-manganese solution to adjust the pH value, adding an oxidizing agent, and separating to obtain filtrate and filter residues; concentrated sulfuric acid is added into the filter residues for curing and leaching, and cured leaching residues and desiliconized filtrate are obtained through separation; cured leaching residues are returned for reduction leaching; adding a second neutralizer into the desiliconized filtrate to adjust the pH value, reacting, and separating to obtain iron-aluminum slag and nickel-containing impurity-removed filtrate; adding a third neutralizer into the nickel-containing impurity-removed filtrate to adjust the pH and precipitate nickel, and separating to obtain a nickel-containing alkaline substance; and removing impurities in the filtrate to obtain the nickel-cobalt-manganese purified liquid. According to the method, the nickel-cobalt-manganese purified liquid, the scandium-containing iron-aluminum slag, the by-product manganese-silicon slag and the like can be obtained, solid waste reduction and high value are achieved, and the method is more economical, more efficient and more environmentally friendly.

Description

Technical Field

[0001] The present invention relates to the technical field of hydrometallurgy, and particularly to a process for preparing a purified solution of nickel, cobalt and manganese by a short process of MHP. Background Art

[0002] Laterite nickel ore has become the main ore resource of nickel raw materials due to its rich reserves, easy mining, low mining cost and other advantages. Nickel-cobalt hydroxide transformed from laterite nickel ore has gradually become the main raw material for producing ternary precursor products for batteries (such as cathode composite materials) because of its lower price than nickel raw materials produced from sulfide nickel ore. This nickel-cobalt hydroxide contains impurities such as iron, aluminum, manganese, magnesium, silicon, etc. in addition to nickel and cobalt.

[0003] At present, the traditional treatment method is to slurry and dissolve the nickel-cobalt hydroxide material, extract and purify it, and then reuse it. However, the leaching process of nickel-cobalt hydroxide is long and complex (requiring multiple steps such as leaching, extraction, stripping, precipitation, etc.), resulting in a production cycle as long as 10 days and a high equipment investment cost (investment per ton exceeds 16,000 yuan); at the same time, it relies on a large amount of chemical reagents (such as extractant P204), which not only keeps the operating cost high, but also generates high-concentration phosphorus-containing wastewater (8 tons / ton of product), and the environmental protection treatment cost is as high as 200 yuan / ton. Moreover, a large amount of silicon is dissolved during the treatment process, affecting the subsequent extraction process, resulting in low nickel-cobalt recovery rate and difficult to meet the strict purity requirements of high-nickel ternary materials (such as NCM811). With the growth of ternary power batteries, the application of nickel in power batteries shows an explosive trend. How to process nickel-cobalt hydroxide intermediate products through a more economical and efficient hydrometallurgy process has attracted the attention of the industry.

[0004] Chinese application CN112210679A discloses a method for preparing nickel sulfate from nickel-cobalt hydroxide. Different from the traditional nickel-cobalt separation process, after the reduction acid leaching process, it uses catalytic oxidation to separate cobalt, manganese, iron from nickel, and at the same time uses neutralization reaction to separate impurity elements such as scandium, aluminum, chromium, etc. By separating the variable-valence metals such as manganese, cobalt, and iron by chemical precipitation at the front end, the obtained first purified solution is almost pure and the impurity content is very low, which reduces the amount of the subsequent extraction purification and nickel-cobalt separation extraction systems a lot, and effectively simplifies the preparation process of nickel sulfate. However, there is still an extraction process, using organic solvents, which pollutes the environment.

[0005] Chinese application CN116334389A discloses a method for leaching and purifying nickel-cobalt-manganese hydroxide intermediate products of laterite nickel ore. By specific acid leaching and pH adjustment steps, the recovery rate of valuable metals is improved, the acid-base consumption and treatment cost are reduced, and the material loss is reduced. The subsequent extraction process is also required.

[0006] Therefore, how to process nickel-cobalt hydroxide intermediate products more economically, efficiently and environmentally friendly still needs to be further improved. Summary of the Invention

[0007] The inventors of the present application have discovered and recognized that the existing nickel-cobalt hydroxide (MHP) raw material treatment process has at least the following problems: the leaching behavior of manganese is uncontrollable during the leaching process, and filtration is difficult; it is difficult to directionally separate the silicon-containing components; the traditional calcium-based neutralization process produces iron-aluminum slag with a high nickel content, resulting in high solid waste treatment costs and low resource utilization rates; it is difficult to efficiently remove impurity ions (such as calcium, magnesium, copper, zinc, silicon, etc.) during the extraction and purification process, which affects the product quality, and the flow rate of the extraction and impurity removal system is large; the process flow is long, the efficiency is low, and the environmental pollution is serious. The present application is made based on the inventors' discovery and recognition of the above facts and problems. The present invention aims to solve at least one of the above technical problems in the related art to a certain extent.

[0008] To this end, according to an embodiment of the present invention, a process for preparing a purified nickel-cobalt-manganese solution with a short MHP process is proposed, and the process includes the following steps: Drying the nickel-cobalt hydroxide raw material with high-temperature steam; Slurrying the dried nickel-cobalt hydroxide raw material, performing reduction leaching after slurrying, controlling the addition amount of the reducing agent, controlling the leaching rate of manganese, performing solid-liquid separation, and obtaining a preliminarily purified nickel-cobalt-manganese solution and manganese-containing slag; Performing acid leaching on the manganese-containing slag, performing solid-liquid separation, and obtaining manganese-silicon slag and a nickel-containing acid washing solution; Adding a first neutralizing agent to the preliminarily purified nickel-cobalt-manganese solution to adjust the pH, adding an oxidizing agent to react, performing solid-liquid separation, and obtaining a filtrate and a filter residue; Adding concentrated sulfuric acid to the filter residue for aging leaching, performing solid-liquid separation, and obtaining an aging leaching residue and a silicon-removing filtrate; returning the aging leaching residue to the reduction leaching stage; Adding a second neutralizing agent to the silicon-removing filtrate to adjust the pH, reacting, performing solid-liquid separation, and obtaining iron-aluminum slag and a nickel-containing impurity-removing filtrate; adding a third neutralizing agent to the nickel-containing impurity-removing filtrate to adjust the pH for nickel precipitation reaction, and performing solid-liquid separation to obtain a nickel-containing basic substance; Removing calcium, magnesium, silicon, copper, and zinc impurities from the filtrate to obtain a purified nickel-cobalt-manganese solution.

[0009] Optionally, when drying the nickel-cobalt hydroxide raw material with high-temperature steam, dry it until the water content is lower than 10%.

[0010] Optionally, in the step of slurrying the dried nickel-cobalt hydroxide raw material and performing reduction leaching after slurrying, the reducing agent is one of H2O2, SO2, and Na2SO3.

[0011] Optionally, the dosage of the reducing agent is controlled such that the ratio of the dosage of the reducing agent to the Mn content in the ore is 0.2 - 1 mol / mol.

[0012] Optionally, after drying the nickel cobalt hydroxide raw material, in the steps of slurrying and then reducing leaching, the slurrying process: the liquid-solid ratio is 2 - 4:1, the reaction temperature is 60 - 90 °C, the final pH is 4.0 - 5.5, the stirring speed is 300 - 800 r / min, and the reaction time is 2 - 4 h.

[0013] Optionally, after drying the nickel cobalt hydroxide raw material, in the steps of slurrying and then reducing leaching, the reducing leaching process: the liquid-solid ratio is 4 - 6:1, the reaction temperature is 60 - 90 °C, the final pH is 1 - 2, the stirring speed is 300 - 800 r / min, and the reaction time is 1.5 - 3 h.

[0014] Optionally, when acid leaching the manganese-containing slag, the liquid-solid ratio is 4 - 6:1, the temperature is 70 - 90 °C, the pH is adjusted to 0.8 - 1.5, and the reaction is carried out for 3 - 5 h; Optionally, it further includes: returning the nickel-containing acid washing solution to the reduction leaching stage.

[0015] Optionally, a first neutralizing agent is added to adjust the pH to 4.5 - 5.2.

[0016] Optionally, the first neutralizing agent is the nickel cobalt hydroxide raw material, or the nickel cobalt hydroxide raw material and the nickel-containing basic substance obtained after the nickel precipitation reaction. Preferably, the first neutralizing agent is the nickel cobalt hydroxide raw material and the nickel-containing basic substance obtained after the nickel precipitation reaction.

[0017] Optionally, when reacting with an oxidizing agent, the temperature is 60 - 90 °C, the stirring speed is 300 - 800 r / min, and the reaction time is 3 - 5 h.

[0018] Optionally, the oxidizing agent is air or H2O2.

[0019] Optionally, the aging leaching process: the acid-ore ratio is 500 - 900 kg / t, stirring is carried out for 1 - 3 h, then water is added to make the liquid-solid ratio 3 - 10:1, the temperature is 80 - 95 °C, and the stirring speed is 300 - 800 r / min.

[0020] Optionally, a second neutralizing agent is added to adjust the pH to 3.5 - 4.0, the reaction time is 3 - 5 h, and the reaction temperature is 40 - 70 °C.

[0021] Optionally, the second neutralizing agent is the nickel cobalt hydroxide raw material and / or Na2CO3. Preferably, the second neutralizing agent is the nickel cobalt hydroxide raw material and Na2CO3.

[0022] Optionally, the third neutralizing agent is Na2CO3. Further optionally, the pH is adjusted to 7-8 by adding the third neutralizing agent for nickel precipitation reaction, the reaction temperature is 40-70 °C, and the reaction time is 2-4 h to obtain a Na2SO4 solution and a nickel-containing basic substance NiCO3.

[0023] Optionally, the Na2SO4 solution is subjected to evaporation crystallization treatment to obtain by-product mirabilite.

[0024] Optionally, calcium, magnesium, silicon, copper, and zinc impurities in the filtrate are removed in sequence to obtain a purified nickel-cobalt-manganese solution; among them, manganese fluoride is used to remove calcium and magnesium; polyferric sulfate is used to remove silicon; manganese powder or iron powder is used to remove copper; nickel sulfide is used to remove zinc.

[0025] Optionally, removing calcium, magnesium, silicon, copper, and zinc impurities in the filtrate in sequence includes the following steps: Removing calcium and magnesium: Mix the filtrate with MnF, stir for 0.5-1 h, the reaction temperature is 60-80 °C, the dosage coefficient of MnF is 1-3 mol / mol, and after the reaction, solid-liquid separation is carried out to obtain a calcium and magnesium-removed filtrate and calcium and magnesium slag; Removing silicon: Mix the calcium and magnesium-removed filtrate with polyferric sulfate, stir for 0.5-2 h, the reaction temperature is 40-60 °C, the dosage coefficient of polyferric sulfate PFS / SiO2 is 80-120 wt% / wt.%, and then solid-liquid separation is carried out to obtain silicon slag and desilicified filtrate; Removing copper: Feed the desilicified filtrate into a copper-removing tank, heat to 40-60 °C, the dosage coefficient of manganese powder is 1-2 mol / mol, react for 1-3 h, and after the reaction, solid-liquid separation is carried out to obtain copper slag and copper-removed filtrate; Removing zinc: Feed the copper-removed filtrate into a zinc-removing tank, heat to 40-50 °C, adjust the pH to 4-6 with sulfuric acid, the reaction time is 1-2 h, the dosage coefficient of nickel sulfide is 1-1.2 mol / mol, and then solid-liquid separation is carried out to obtain zinc slag and a purified nickel-cobalt-manganese solution.

[0026] Optionally, for the process, the nickel and cobalt leaching rate ≥ 98%, and the controllable range of the manganese leaching rate is 35%-99%.

[0027] Optionally, the average concentration of key impurities in the purified nickel-cobalt-manganese solution is less than 50 ppm; the key impurities include calcium, magnesium, copper, zinc, and silicon.

[0028] Beneficial effects: According to an embodiment of the present invention, a process for preparing purified nickel-cobalt-manganese solution by a short MHP process is provided. Through an innovative short process technology of leaching-neutralization-precipitation, directly using MHP as a raw material, the efficient dissolution of nickel, cobalt, and manganese is achieved by precisely controlling the leaching conditions. Combining neutralization and directional precipitation technologies to remove impurities synchronously, high-purity nickel-cobalt-manganese solution is prepared in one step. The present invention completely abandons the traditional extraction link, promotes the upgrading of nickel-cobalt resource development in China towards short processes and high added value, and provides core support for cost reduction and efficiency improvement in the new energy industry chain.

[0029] Compared with the prior art, some embodiments of the present invention also have the following advantages: 1. The present invention adopts a high-temperature pretreatment-segmented acid control-redox synergistic leaching technology. By using high-temperature pretreatment to achieve the transformation of the silicon crystal form, the filtration performance of the leaching solution is significantly improved. By using segmented acid control to regulate the valence state of manganese and controlling the dosage of the reducing agent, while improving the leaching of nickel and cobalt, the controllable leaching of manganese is achieved, providing conditions for different market demands of nickel-cobalt-manganese ratios.

[0030] 2. The present invention adopts a slag acid ripening and two-stage gradient neutralization precipitation process to selectively precipitate iron and aluminum ions, obtaining scandium-containing iron-aluminum slag and recyclable high-nickel alkaline substances, etc., realizing the resource utilization of waste. In some embodiments, by utilizing the alkaline characteristics of nickel-cobalt hydroxide in MHP and NiCO3 generated in subsequent processes, the selective precipitation of iron and aluminum ions is achieved, effectively suppressing the introduction of calcium and magnesium ions. Through secondary removal of silicon impurities and an innovative two-stage gradient neutralization process, scandium-containing iron-aluminum slag, recyclable high-nickel alkaline substances, and high-purity mirabilite are obtained, realizing the resource utilization of waste.

[0031] 3. In some embodiments of the present invention, for the obtained filtrate, a process of removing calcium and magnesium with manganese fluoride, removing copper with manganese powder and iron powder, removing zinc with nickel sulfide, and removing silicon with polyferric sulfate is used for purification, breaking through the limit of traditional purification processes for the removal of trace impurities, making the concentration of key impurities in the nickel-cobalt-manganese purified solution lower than 50 ppm, and it can be directly used for the preparation of ternary precursors.

[0032] 4. The process for preparing nickel-cobalt-manganese purified solution by the short MHP process proposed by the present invention has the advantages of being more economical, more efficient, and more environmentally friendly. High efficiency: The leaching rate of nickel and cobalt is ≥98%, and the controllable range of the manganese leaching rate is 35% - 99%. Environmental protection: Resource utilization of solid waste, reducing environmental pollution. Economy: Short process design, reducing production costs. Description of the Drawings

[0033] Figure 1 is a flow chart of the process for preparing nickel-cobalt-manganese purified solution by the short MHP process in an embodiment of the present invention. Detailed Embodiments

[0034] To better illustrate the present application and facilitate the understanding of the technical solution of the present invention, the present invention will be further described in detail below. Obviously, the following embodiments are only a part of the embodiments of the present invention, rather than all embodiments. The description of at least one exemplary embodiment below is actually only illustrative and in no way limits the present invention and its application or use. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts belong to the scope of protection of the present invention.

[0035] In an embodiment of the present application, a process for preparing a purified nickel-cobalt-manganese solution by a short MHP process is provided, including the following steps: (1) Drying the nickel-cobalt hydroxide raw material with high-temperature steam; (2) Pulping the dried nickel-cobalt hydroxide raw material, performing reduction leaching after pulping, controlling the addition amount of the reducing agent, controlling the leaching rate of manganese, and performing solid-liquid separation to obtain a preliminarily purified nickel-cobalt-manganese solution and a manganese-containing slag; (3) Acidifying and leaching the manganese-containing slag, and performing solid-liquid separation to obtain a manganese-silicon slag and a nickel-containing pickling solution; (4) Adding a first neutralizing agent to the preliminarily purified nickel-cobalt-manganese solution to adjust the pH, adding an oxidizing agent to react, and performing solid-liquid separation to obtain a filtrate and a filter residue; (5) Adding concentrated sulfuric acid to the filter residue for aging leaching, performing solid-liquid separation to obtain an aging leaching residue and a desiliconized filtrate; returning the aging leaching residue to step (2); (6) Adding a second neutralizing agent to the desiliconized filtrate to adjust the pH, reacting, and performing solid-liquid separation to obtain an iron-aluminum slag and a nickel-containing impurity-removing filtrate; adding a third neutralizing agent to the nickel-containing impurity-removing filtrate to adjust the pH for nickel precipitation reaction to obtain a nickel-containing basic substance; (7) Removing impurities such as calcium, magnesium, silicon, copper, and zinc in the filtrate to obtain a purified nickel-cobalt-manganese solution.

[0036] In some embodiments of the present invention, through the silica crystallization - segmented acid control - redox synergistic leaching technology, a preliminarily purified nickel-cobalt-manganese impurity-containing solution that is easy to filter and a high-manganese slag are obtained. During the post-neutralization iron-aluminum removal and the harmless treatment of the iron-aluminum slag, an MHP self-circulation neutralization control system is constructed, and processes such as slag acid aging - secondary precipitation are adopted to obtain a scandium-containing iron-aluminum slag, a recyclable high-nickel basic substance, and high-purity mirabilite, realizing solid waste reduction and high value-added. Finally, during the deep purification and impurity removal of the neutralized solution, precise targeted removal of impurity ions is achieved through multi-scale interface control, and a nickel-cobalt-manganese solution with a key impurity concentration lower than 50 ppm that can be directly used for the preparation of ternary precursors is obtained.

[0037] Step (1) of the present invention realizes the transformation of the silicon crystal form through high-temperature pretreatment, significantly improving the filtration performance of the subsequent leaching solution. Further, the nickel-cobalt hydroxide raw material is dried by high-temperature steam until the water content is less than 10%. Further still, it can be dried to have no moisture at all to maximize the improvement of the filtration performance of the leaching solution. In addition, the high-temperature steam can be the residual high-temperature steam in the three-stage preheating and three-stage flash evaporation process in the laterite nickel ore leaching plant area or the high-temperature steam generated in the sulfuric acid production process. In this way, the excess high-temperature steam is recycled; the nickel-cobalt hydroxide raw material dried in the step is transported over a long distance, reducing the transportation cost.

[0038] Based on the raw material after high-temperature pretreatment in step (2) of the present invention, sectional acid control (pulping and reduction) is used to control the manganese leaching, obtaining a high-manganese slag (the high-manganese slag is further acidified and treated to be converted into a manganese-silicon slag product that can be sold externally), and at the same time obtaining a preliminarily purified and easily filtered nickel-cobalt-manganese impurity-containing solution. Subsequently, selective precipitation of iron and aluminum ions is carried out based on this nickel-cobalt-manganese solution.

[0039] In some preferred embodiments, in the pulping process: first, water is added to the dried nickel-cobalt hydroxide raw material, the liquid-solid ratio is adjusted to 2-4:1, then concentrated sulfuric acid is added, the end-point pH is adjusted to 4.0-5.5, the reaction temperature is 60-90 °C, the stirring speed is 300-800 r / min, and the reaction time is 2-4 h.

[0040] In some preferred embodiments, in the reduction leaching process: the liquid-solid ratio is 4-6:1, the reaction temperature is 60-90 °C, the end-point pH is 1-2, the stirring speed is 300-800 r / min, and the reaction time is 1.5-3 h. Among them, the reducing agent is one of H2O2, SO2, and Na2SO3. Preferably, the reducing agent usage coefficient: the amount of reducing agent used / the Mn content in the ore is 0.2-1 mol / mol.

[0041] In the above preferred embodiments, based on sectional acid control, by precisely controlling sectional acid control (that is, adjusting the pH to 4.0-5.5 in the pulping stage and then adjusting the pH to 1-2 in the reduction leaching stage), the conditions of pulping and reduction leaching are precisely controlled, further improving the nickel-cobalt leaching rate while realizing controllable manganese leaching. The controllable range of the manganese leaching rate is 35%-99%, providing conditions for different market demands of nickel-cobalt-manganese ratios.

[0042] Based on the high-manganese slag obtained by the above pulping + reduction in step (3) of the present invention, through the use of an acid leaching process, a manganese-silicon slag that can be directly sold as a product and a nickel-containing acid washing solution are obtained. The nickel-containing acid washing solution can be returned for utilization, and in addition, nickel can be further recovered.

[0043] In some preferred embodiments, the acid leaching conditions are as follows: the liquid-solid ratio is 4-6:1, the temperature is 70-90 °C, the pH is adjusted to 0.8-1.5, and the reaction lasts for 3-5 h. By adopting the above acid leaching conditions, the leaching rate of manganese and silicon can be further improved.

[0044] Steps (4)-(6) of the present invention are based on the preliminarily purified and easily filterable nickel-cobalt-manganese impurity-containing solution obtained in step (2), and adopt a process combining aging leaching and secondary precipitation (iron and aluminum removal in the first stage - aging leaching - iron and aluminum removal in the second stage) to selectively precipitate iron and aluminum ions, obtaining a scandium-containing iron and aluminum slag, and further recovering nickel to obtain a highly nickel-containing alkaline substance that can be recycled, etc., realizing solid waste reduction and high value utilization.

[0045] In some preferred embodiments, in step 4), a first neutralizing agent is added to the preliminarily purified nickel-cobalt-manganese solution to adjust the pH to 4.5-5.2. Among them, the first neutralizing agent is a nickel-cobalt hydroxide raw material, or a nickel-cobalt hydroxide raw material and a nickel-containing alkaline substance obtained after the nickel precipitation reaction, which can avoid the introduction of impurity ions.

[0046] In addition, the inventors of the present application noticed that: when the pH is above 2, the nickel-cobalt hydroxide raw material is not easily dissolved. (When using nickel-cobalt hydroxide alone as the first neutralizing agent), a large amount of raw materials are required for pH adjustment, and it will enter the iron and aluminum slag, increasing the nickel and cobalt loss rate; while the highly nickel-containing alkaline substance obtained by the nickel precipitation reaction of the present invention is easy to adjust the pH, but its amount is small.

[0047] Based on this, preferably, a nickel-cobalt hydroxide raw material and a nickel-containing alkaline substance obtained after the nickel precipitation reaction are used as the first neutralizing agent. According to the design calculation, first, the nickel-cobalt hydroxide raw material is used to adjust the pH to a certain value (the pH range can be 1-2), and then all the highly nickel-containing alkaline substances obtained after the subsequent nickel precipitation reaction are used to adjust to the required pH. By using the alkaline properties of nickel-cobalt hydroxide in MHP and NiCO3 generated in the subsequent process to adjust the pH in turn, the selective precipitation of iron and aluminum ions is realized, effectively suppressing the introduction of calcium and magnesium ions, saving costs and reducing the nickel and cobalt loss rate.

[0048] Further, when adding an oxidant for reaction, the reaction temperature is 60-90 °C, the stirring speed is 300-800 r / min, and the reaction time is 3-5 h to further improve the reaction efficiency of the first precipitation. Among them, the oxidant is air or H2O2. Further, the amount of the oxidant is controlled during the reaction, the air flow rate is 50-200 mL / min, and the H2O2 dosage is 1.4 kg / t 液量 。

[0049] In some preferred embodiments, in step 5), when the filter residue obtained from the first-stage iron and aluminum removal is mixed with concentrated sulfuric acid for aging leaching, the aging leaching process is as follows: the acid-to-ore ratio is 500 - 900 kg / t, stirring is carried out for 1 - 3 h, then water is added to make the liquid-solid ratio 3 - 10:1, the temperature is 80 - 95 °C, and the stirring speed is 300 - 800 r / min. By adding concentrated sulfuric acid and carrying out aging leaching on the filter cake obtained from the first-stage iron and aluminum removal under the above conditions, nickel and cobalt in the filter residue obtained in step 4) can be further recovered, and the overall leaching efficiency can be improved. After solid-liquid separation, a desiliconized filtrate and an aging leaching residue are obtained. The removal of silicon in the desiliconized filtrate reduces the influence of the generation of silica gel on subsequent processes (such as the precipitation of nickel and cobalt, the filtration rate, etc.).

[0050] The so-called aging leaching is that the material and concentrated acid are subjected to intense leaching (without adding water). This leaching will change the form of silicon, thus converting the difficult-to-filter silica gel form into an easy-to-filter silica form. By returning the aging leaching residue after aging leaching to the pulping + leaching stage, that is, returning the aging leaching residue containing easy-to-filter silica to the leaching stage, the filtration of the leaching slurry can be further improved, and silicon enters the slag in the leaching stage and forms a manganese-silicon slag that can be sold externally after treatment.

[0051] In some preferred embodiments, in step 6), a second neutralizing agent is added to the desiliconized filtrate to adjust the pH to 3.5 - 4.0, the reaction time is 3 - 5 h, and the reaction temperature is 40 - 70 °C. Under the above conditions, second-stage iron and aluminum removal is carried out, further improving the reaction efficiency of secondary precipitation, and obtaining a scandium-containing iron and aluminum slag and a nickel-containing impurity-removing filtrate.

[0052] Among them, the second neutralizing agent can be a nickel-cobalt hydroxide raw material, can be Na2CO3, or can be a nickel-cobalt hydroxide raw material and Na2CO3.

[0053] The inventors of the present application found that: if sodium carbonate is added alone as the second neutralizing agent, the content of nickel and cobalt in the iron and aluminum slag will be reduced, and the nickel and cobalt loss rate will be reduced. However, the dosage of sodium carbonate will increase, increasing the cost. If nickel-cobalt hydroxide is added alone and used as the second neutralizing agent, the cost can be saved. However, when the nickel-cobalt hydroxide raw material has a pH value above 2, it is not easily soluble, and a large amount of nickel-cobalt hydroxide is required for pH adjustment, and it will enter the iron and aluminum slag, increasing the nickel and cobalt loss rate.

[0054] Based on this, preferably, nickel-cobalt hydroxide can be added first to appropriately adjust the pH, and then sodium carbonate can be added to adjust to the required pH, saving sodium carbonate and reducing the cost. Specifically, it can be calculated according to the design. First, the nickel-cobalt hydroxide raw material is used to adjust the pH to a value, such as adjusting the pH to the range of 1 - 2, and then sodium carbonate is used to adjust to the required pH. By adjusting with the two in sequence, not only the selective precipitation of iron and aluminum ions is realized, effectively inhibiting the introduction of calcium and magnesium ions, but also the cost is saved and the nickel and cobalt loss rate is reduced.

[0055] In some preferred embodiments, a third neutralizing agent Na2CO3 is added to the nickel-containing impurity-removing filtrate obtained by solid-liquid separation after secondary precipitation to adjust the pH to 7-8, and a nickel precipitation reaction is carried out. The reaction time is 2-4 h, the reaction temperature is 40-70 °C. After the reaction, solid-liquid separation is carried out to obtain a filter residue of high-nickel basic substance NiCO3 and a filtrate of Na2SO4. Among them, as described above, all the filter residue NiCO3 can be recycled, and the filtrate Na2SO4 is evaporated and crystallized to obtain a by-product mirabilite. By adopting processes such as slag acid ripening-secondary precipitation, a scandium-containing iron-aluminum slag, a recyclable high-nickel basic substance, and a by-product high-purity mirabilite are obtained, realizing solid waste reduction and high value-added.

[0056] In step (7) of the present invention, the neutralized solution obtained by solid-liquid separation after iron and aluminum removal in the first stage is deeply purified to remove impurities such as calcium, magnesium, silicon, copper, and zinc, so as to obtain a purified nickel-cobalt-manganese solution and a nickel-cobalt-manganese purified solution.

[0057] In some preferred embodiments, processes such as manganese fluoride for removing calcium and magnesium, manganese powder and iron powder for removing copper, nickel sulfide for removing zinc, and polyferric sulfate for removing silicon are successively adopted to treat the neutralized solution. Through multi-scale interface regulation, precise targeted removal of impurity ions is achieved, breaking through the limit of traditional purification processes for removing trace impurities, and making the concentration of key impurities in the nickel-cobalt-manganese purified solution lower than 50 ppm, which can be directly used for the preparation of ternary precursors.

[0058] Specifically, it may include the following steps: Manganese fluoride for removing calcium and magnesium: The filtrate is mixed with MnF, stirred for 0.5-1 h, the reaction temperature is 60-80 °C, the dosage coefficient of MnF is 1-3 mol / mol. After the reaction, solid-liquid separation is carried out to obtain a calcium and magnesium-removed filtrate and a calcium and magnesium slag.

[0059] Polyferric sulfate for removing silicon: The calcium and magnesium-removed filtrate is mixed with polyferric sulfate PFS, stirred for 0.5-2 h, the reaction temperature is 40-60 °C, the dosage coefficient of polyferric sulfate PFS / SiO2 is 80-120 wt% / wt.%. Then solid-liquid separation is carried out to obtain a silicon slag and a silicon-removed filtrate. Among them, after adding polyferric sulfate, the pH drops, and the pH needs to be adjusted to 4.5-5.0 within 8 min and maintained. The agent for adjusting the pH is a 90-98 wt.% NaOH solution. The removal of silicon can be more efficient through the flocculation of polyferric sulfate, reducing the silicon content in the solution. The operation is easy and no new impurities are brought to the system. After polyferric sulfate hydrolyzes in water, it will generate polynuclear complexes, which have an electro-neutralization effect. The positively charged groups can adsorb negatively charged silica colloids (such as silicic acid colloids), and at the same time form large flocs through bridging flocculation, wrapping and precipitating the silicon particles to remove them. Utilizing the high-molecular flocculation performance and strong electro-neutralization ability of polyferric sulfate, other pollutants such as Pb 2+ 、Cu 2+Heavy metal ions such as, organic matters such as COD, phosphorus, etc. Compared with traditional iron salts or aluminum salts, the high molecular structure of polyferric sulfate makes its adsorption of silicon more efficient, and the silicon removal rate can be increased by 10% - 30%.

[0060] Copper removal by manganese powder and iron powder: The desiliconized filtrate is pumped into the copper removal tank, heated to 40 - 60 °C, the dosage coefficient of Mn powder is 1 - 2 mol / mol, react for 1 - 3 h, and after solid-liquid separation, copper slag and copper-removed filtrate are obtained.

[0061] Zinc removal by nickel sulfide: The copper-removed filtrate is pumped into the zinc removal tank, heated to 40 - 50 °C, adjust the pH to 4 - 6 with sulfuric acid, the reaction time is 1 - 2 h, the dosage coefficient of nickel sulfide is 1 - 1.2 mol / mol, and after solid-liquid separation, zinc slag and nickel-cobalt-manganese purified liquid are obtained.

[0062] The technical solutions in the present invention will be further described below in conjunction with specific embodiments and the accompanying drawings: Example 1

[0063] High-temperature pretreatment: The nickel cobalt hydroxide raw material is dried with high-temperature steam.

[0064] Slurrying + leaching: The dried nickel cobalt hydroxide raw material is slurried. First, add water, the liquid-solid ratio is 3:1, the temperature is 80 °C, add concentrated sulfuric acid to adjust the pH to 4.8, and the reaction time is 3 h; after slurrying, reduction leaching is carried out, the liquid-solid ratio is 5:1, the temperature is 80 °C, add concentrated sulfuric acid to adjust the pH to 1.5, the reducing agent is H2O2, the dosage / Mn content in the ore is 0.2 mol / mol, and after filtration, a preliminarily purified nickel-cobalt-manganese solution and a high-manganese slag are obtained.

[0065] Acid leaching of the high-manganese slag: The liquid-solid ratio is 5:1, the temperature is 90 °C, adjust the pH to 1, react for 3 h, and after filtration, a manganese-silicon slag and a nickel-containing acid leaching solution are obtained. Among them, the nickel-containing acid leaching solution can be returned to the slurrying + leaching step.

[0066] First-stage iron and aluminum removal: Add the first neutralizing agent, nickel cobalt hydroxide raw material, to the preliminarily purified nickel-cobalt-manganese solution to adjust the pH to 4.5 (or first add the neutralizing agent nickel cobalt hydroxide raw material to adjust the pH to a value, and then use NiCO3 obtained from the subsequent process to adjust the pH to 4.5), the oxidant is air, react for 4 h, and after solid-liquid separation, a filtrate and a filter residue (i.e., filter cake) are obtained.

[0067] Aging leaching: Mix the filter residue with concentrated sulfuric acid, the acid-ore ratio is 800 kg / t, stir for 3 h, then add water to make the liquid-solid ratio 6:1, the test temperature is 90 °C, and the stirring speed is 500 r / min; after solid-liquid separation, an aging leaching residue and a desiliconized filtrate are obtained, and the aging leaching residue is returned to the slurrying + leaching stage.

[0068] Two-stage iron and aluminum removal: Add the second neutralizing agent, nickel-cobalt hydroxide raw material, to the desilication filtrate to adjust the pH to 3.5 (alternatively, first add the nickel-cobalt hydroxide raw material as the neutralizing agent to adjust the pH to a certain value, and then add Na2CO3 to adjust the pH to 3.5). The reaction time is 4 h, the reaction temperature is 70 °C, and then solid-liquid separation is carried out to obtain the iron-aluminum slag and the impurity-removed filtrate.

[0069] Nickel precipitation: Add the third neutralizing agent, Na2CO3, to the impurity-removed filtrate to adjust the pH to 8, react for 3 h, and the reaction temperature is 60 °C. After nickel precipitation, solid-liquid separation is carried out to obtain the filter residue NiCO3 and the filtrate Na2SO4; the filter residue NiCO3 can be recycled to the first-stage iron and aluminum removal, and the filtrate Na2SO4 is evaporated and crystallized to obtain the by-product mirabilite.

[0070] Impurity removal: Add MnF with a dosage coefficient of 2 mol / mol to the filtrate obtained from the neutralization of iron and aluminum removal, i.e., the first-stage iron and aluminum removal step, stir for 1 h, and the reaction temperature is 70 °C. Then solid-liquid separation is carried out to obtain the calcium and magnesium removal filtrate and the calcium and magnesium slag; add polyferric sulfate with a dosage coefficient of PFS / SiO2 of 80 wt% / wt.% to the calcium and magnesium removal filtrate, stir for 0.5 h, and the reaction temperature is 50 °C to obtain the silicon slag and the desilication filtrate; add Mn powder with a dosage coefficient of 1.5 mol / mol to the desilication filtrate, heat to 50 °C, stir for 1 h, and carry out solid-liquid separation to obtain the copper slag and the copper removal filtrate; adjust the pH of the copper removal filtrate to 5, then add nickel sulfide with a dosage coefficient of 1 mol / mol, heat to 45 °C, stir for 1 h, and carry out solid-liquid separation to obtain the zinc slag and the purified nickel-cobalt-manganese solution; The test results are as follows: The nickel-cobalt leaching rate is 98%, the manganese leaching rate is 45%, the nickel content in the iron-aluminum slag is 0.5%, and the silicon removal rate is 95%. In the purified nickel-cobalt-manganese solution, the residual calcium and magnesium content is 30 ppm, the residual copper and zinc content is 0.8 ppm, and the silicon content is 30 ppm.

[0071] The description of the present invention is given for purposes of illustration and description, and is not intended to be exhaustive or to limit the invention to the disclosed form. Many modifications and variations are obvious to those of ordinary skill in the art. The embodiments are chosen and described in order to best explain the principles of the invention and its practical application, and to enable those of ordinary skill in the art to understand the invention so as to design various embodiments with various modifications suitable for specific purposes.

Claims

1. A process for preparing a purified solution of nickel, cobalt and manganese by a short MHP process, characterized in that, Including: Drying the nickel cobalt hydroxide raw material with high-temperature steam; Slurrying the dried nickel cobalt hydroxide raw material, subjecting it to reduction leaching after slurrying, controlling the addition amount of the reducing agent, controlling the leaching rate of manganese, and performing solid-liquid separation to obtain a preliminarily purified nickel cobalt manganese solution and a manganese-containing residue; Subjecting the manganese-containing residue to acid leaching, and performing solid-liquid separation to obtain a manganese silicon residue and a nickel-containing pickling solution; Adding a first neutralizing agent to the preliminarily purified nickel cobalt manganese solution to adjust the pH, adding an oxidizing agent for reaction, and performing solid-liquid separation to obtain a filtrate and a filter residue; Adding concentrated sulfuric acid to the filter residue for aging leaching, performing solid-liquid separation to obtain an aging leaching residue and a silicon-removing filtrate; returning the aging leaching residue to the reduction leaching stage; Adding a second neutralizing agent to the silicon-removing filtrate to adjust the pH, reacting, and performing solid-liquid separation to obtain an iron-aluminum residue and a nickel-containing impurity-removing filtrate; adding a third neutralizing agent to the nickel-containing impurity-removing filtrate to adjust the pH for nickel precipitation reaction, and performing solid-liquid separation to obtain a nickel-containing basic substance; Removing impurities such as calcium, magnesium, silicon, copper, and zinc in the filtrate to obtain a purified nickel cobalt manganese solution.

2. The process for preparing a purified nickel-cobalt-manganese solution by the MHP short process according to claim 1, characterized in that, When drying the nickel cobalt hydroxide raw material with high-temperature steam, drying it until the water content is lower than 10%.

3. The process for preparing a purified nickel-cobalt-manganese solution by the MHP short process according to claim 1, characterized in that, In the step of slurrying the dried nickel cobalt hydroxide raw material and subjecting it to reduction leaching after slurrying, The reducing agent is one of H2O2, SO2, and Na2SO3; the dosage of the reducing agent is controlled as: the dosage of the reducing agent / the Mn content in the ore is 0.2 - 1 mol / mol; Slurrying process: the liquid-solid ratio is 2 - 4:1, the reaction temperature is 60 - 90 °C, the end-point pH is 4.0 - 5.5, the stirring speed is 300 - 800 r / min, and the reaction time is 2 - 4 h; Reduction leaching process: the liquid-solid ratio is 4 - 6:1, the reaction temperature is 60 - 90 °C, the end-point pH is 1 - 2, the stirring speed is 300 - 800 r / min, and the reaction time is 1.5 - 3 h.

4. The process for preparing a purified solution of nickel, cobalt and manganese by the MHP short process according to claim 1, characterized in that, When subjecting the manganese-containing residue to acid leaching, the liquid-solid ratio is 4 - 6:1, the temperature is 70 - 90 °C, the pH is adjusted to 0.8 - 1.5, and the reaction is carried out for 3 - 5 h; It also includes: returning the nickel-containing pickling solution to the reduction leaching stage.

5. The process for preparing a purified nickel-cobalt-manganese solution by the MHP short process according to claim 1, characterized in that, Adding a first neutralizing agent to adjust the pH to 4.5 - 5.2; when adding an oxidizing agent for reaction, the temperature is 60 - 90 °C, the stirring speed is 300 - 800 r / min, and the reaction time is 3 - 5 h; The first neutralizing agent is the nickel cobalt hydroxide raw material, or the nickel cobalt hydroxide raw material and the nickel-containing basic substance obtained after the nickel precipitation reaction; the oxidizing agent is air or H2O2.

6. The process for preparing a purified nickel-cobalt-manganese solution by the MHP short process according to claim 1, characterized in that, Aging leaching process: the acid-ore ratio is 500 - 900 kg / t, stirring for 1 - 3 h, then adding water to make the liquid-solid ratio 3 - 10:1, the temperature is 80 - 95 °C, and the stirring speed is 300 - 800 r / min; Adding a second neutralizing agent to adjust the pH to 3.5 - 4.0, the reaction time is 3 - 5 h, and the reaction temperature is 40 - 70 °C; the second neutralizing agent is the nickel cobalt hydroxide raw material and / or Na2CO3.

7. The process for preparing a purified nickel-cobalt-manganese solution by the MHP short process according to claim 6, characterized in that, The third neutralizing agent is Na2CO3; adding the third neutralizing agent to adjust the pH to 7-8 for the nickel precipitation reaction, the reaction temperature is 40-70 °C, and the reaction time is 2-4 h to obtain a Na2SO4 solution and a nickel-containing basic substance NiCO3; Perform evaporation crystallization treatment on the Na2SO4 solution to obtain the by-product mirabilite.

8. The process for preparing a purified nickel-cobalt-manganese solution by the MHP short process according to any one of claims 1-7, characterized in that, Remove calcium, magnesium, silicon, copper, and zinc impurities in the filtrate in sequence to obtain a nickel-cobalt-manganese purification solution; among them, manganese fluoride is used to remove calcium and magnesium; polyferric sulfate is used to remove silicon; manganese powder or iron powder is used to remove copper; nickel sulfide is used to remove zinc.

9. The process for preparing a purified nickel-cobalt-manganese solution by the MHP short process according to claim 8, characterized in that, Removing calcium, magnesium, silicon, copper, and zinc impurities in the filtrate in sequence includes the following steps: Removing calcium and magnesium: Mix the filtrate with MnF, stir for 0.5-1 h, the reaction temperature is 60-80 °C, the dosage coefficient of MnF is 1-3 mol / mol, and after the reaction, solid-liquid separation is carried out to obtain a calcium and magnesium-removed filtrate and calcium and magnesium slag; Removing silicon: Mix the calcium and magnesium-removed filtrate with polyferric sulfate, stir for 0.5-2 h, the reaction temperature is 40-60 °C, the dosage coefficient of polyferric sulfate PFS / SiO2 is 80-120 wt% / wt.%, and then solid-liquid separation is carried out to obtain silicon slag and desiliconized filtrate; Removing copper: Pump the desiliconized filtrate into a copper removal tank, heat it to 40-60 °C, the dosage coefficient of manganese powder is 1-2 mol / mol, react for 1-3 h, and after the reaction, solid-liquid separation is carried out to obtain copper slag and copper-removed filtrate; Removing zinc: Pump the copper-removed filtrate into a zinc removal tank, heat it to 40-50 °C, add sulfuric acid to adjust the pH to 4-6, the reaction time is 1-2 h, the dosage coefficient of nickel sulfide is 1-1.2 mol / mol, and then solid-liquid separation is carried out to obtain zinc slag and nickel-cobalt-manganese purification solution.

10. The process for preparing a purified nickel-cobalt-manganese solution by the MHP short process according to claim 9, characterized in that, The nickel-cobalt leaching rate ≥ 98%, and the controllable range of the manganese leaching rate is 35%-99%; The average concentration of key impurities in the nickel-cobalt-manganese purification solution is less than 50 ppm; the key impurities include calcium, magnesium, copper, zinc, and silicon.

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