Method for preparing high-pressure leachate and method for preparing nickel cobalt hydroxide

Abstract

The invention discloses a method for preparing a high-pressure leachate and a method for preparing nickel cobalt hydroxide, and the method comprises the following steps: carrying out high-pressure acid leaching treatment on reduced laterite-nickel ore pulp to obtain the high-pressure leachate, mixing the reduced laterite-nickel ore pulp with an oxidizing agent before the high-pressure acid leaching treatment, and / or adding the high-pressure leachate to the reducing laterite-nickel ore pulp to obtain the high-pressure leachate, the oxidizing agent is added in the high-pressure acid leaching treatment process. The method is simple in production process, and the smelting cost of the reduced laterite-nickel ore is reduced.

Description

Technical Field

[0001] The present application relates to the field of metallurgical technology, and in particular, to a method for preparing a high-pressure leaching solution using laterite nickel ore and a method for preparing nickel cobalt hydroxide. Background Art

[0002] Nickel and cobalt are very important basic raw materials for modern industry. With the rapid increase in the consumption ratio of nickel and cobalt in new energy batteries and other fields, the development and utilization of nickel and cobalt mines have become more important in reality. Laterite nickel ore is an important nickel ore resource, mainly formed by long-term weathering of ultrabasic rocks. The nickel in laterite nickel ore is mainly composed of nickel oxides, hydroxides and silicate minerals, but the nickel content in laterite nickel ore is relatively low, usually between 1% and 3%, which makes its mining and smelting costs relatively high. At the same time, a large amount of tailings and wastewater may be generated during the mining and smelting of laterite nickel ore, and its production and application technology needs further research and development and improvement. Summary of the invention

[0003] In a first aspect of the present application, the present application proposes a method for preparing a high-pressure leaching solution, comprising: subjecting a reduced laterite nickel ore slurry to a high-pressure acid leaching treatment to obtain a high-pressure leaching solution, wherein the reduced laterite nickel ore slurry and an oxidant are mixed before the high-pressure acid leaching treatment, and / or the oxidant is added during the high-pressure acid leaching treatment.

[0004] The method for preparing a high-pressure leaching solution is used to treat reduced laterite nickel ore. An oxidant is introduced before and / or during high-pressure acid leaching. The oxidant fully oxidizes reducing substances in the reduced laterite nickel ore slurry during the acid leaching process, thereby reducing interference of the reducing substances on subsequent processes. The formed high-pressure leaching solution can be processed more conveniently to fully separate metal elements. The production process is simple and the smelting cost of the reduced laterite nickel ore is reduced.

[0005] In some embodiments, the high-pressure leaching solution includes sulfuric acid with a mass concentration of 15 g / L-60 g / L.

[0006] In some embodiments, the dry weight ratio of the oxidant to the reduced laterite nickel ore slurry is less than or equal to 0.05. The dry weight ratio is the dry basis mass ratio of the oxidant to the reduced laterite nickel ore slurry. Within the aforementioned dry weight ratio range, the addition of the oxidant can achieve the effect of oxidizing the reducing substances in the reduced laterite nickel ore slurry and reduce the waste of the oxidant.

[0007] In some embodiments, the average valence of the manganese element in the oxidant is higher than +2, thereby achieving a better oxidation effect.

[0008] In some embodiments, the molar ratio of tetravalent manganese in the manganese element in the oxidant is greater than or equal to 90%.

[0009] In some embodiments, the oxidant includes at least one of pyrolusite and manganite. Using manganese-containing minerals as oxidants can achieve better oxidation effects and can be recycled and reused in subsequent processing.

[0010] In some embodiments, the particle size of the oxide is less than or equal to 3 mm, thereby facilitating a relatively fast and controllable oxidation reaction.

[0011] In some embodiments, the temperature of the high pressure acid leaching treatment is 240° C.-280° C., and the pressure of the high pressure acid leaching treatment is 3.0 MPa-6.0 MPa. Within the above temperature and pressure ranges, more nickel and cobalt elements in the reduced laterite nickel ore slurry can enter the high pressure leaching solution.

[0012] In some embodiments, the high pressure acid leaching treatment lasts for 0.5 h to 2 h. Within the aforementioned time range, the leaching of nickel and cobalt elements in the reduced laterite nickel ore slurry is relatively sufficient.

[0013] In the second aspect of the present application, the present application proposes a method for preparing nickel cobalt hydroxide, wherein a high-pressure leachate is subjected to an iron-aluminum removal treatment to obtain an iron-aluminum precipitate and an iron-aluminum removal leachate, wherein the high-pressure leachate is prepared by the method proposed in the present application; the iron-aluminum removal leachate is subjected to a nickel-cobalt precipitation treatment to obtain a nickel-cobalt product and a nickel-cobalt leachate, wherein the nickel-cobalt product includes nickel cobalt hydroxide.

[0014] By removing iron and aluminum from the high-pressure leaching solution, the iron and aluminum impurities in the reduced laterite nickel ore can be removed; and the iron and aluminum leaching solution is then subjected to nickel and cobalt precipitation treatment to extract the nickel and cobalt elements in the reduced laterite nickel ore and improve the metal purity of the prepared nickel-cobalt product.

[0015] In some embodiments, the method further comprises: pre-neutralizing the high-pressure leaching solution so that the pH value of the high-pressure leaching solution is 1.5-2.0. This helps to control the pH value of the high-pressure leaching solution, so that the pH value of the high-pressure leaching solution is closer to the pH value range of the iron and aluminum removal treatment, reduces the amount of neutralizer required to be added for adjusting the pH value in the subsequent iron and aluminum removal treatment, is conducive to controlling the pH value change, and shortens the time of the iron and aluminum removal treatment.

[0016] In some embodiments, the iron removal and aluminum removal treatment includes a first iron removal and aluminum removal treatment and a second iron removal and aluminum removal treatment, wherein the first iron removal and aluminum removal treatment is performed on the high-pressure leachate to obtain a first iron and aluminum precipitate and a first iron removal and aluminum removal leachate, wherein the pH value of the first iron removal and aluminum removal leachate is 3.5-4.0; the second iron removal and aluminum removal treatment is performed on the first iron removal and aluminum removal leachate to obtain a second iron and aluminum precipitate and a second iron removal and aluminum removal leachate, wherein the pH value of the second iron removal and aluminum removal leachate is 4.5-5.0. Thus, by adjusting the pH value, the iron and aluminum elements are separated from the iron removal and aluminum removal leachate in the form of precipitation through solid-liquid separation to achieve the removal of the iron and aluminum elements.

[0017] In some embodiments, the nickel-cobalt precipitation treatment includes a first nickel-cobalt precipitation treatment and a second nickel-cobalt precipitation treatment, wherein the first nickel-cobalt precipitation treatment is performed on the iron-aluminum-removed leachate to obtain the nickel-cobalt product and the first nickel-cobalt leachate, wherein the pH value of the first nickel-cobalt leachate is 7.0-7.6; the second nickel-cobalt precipitation treatment is performed on the first nickel-cobalt leachate to obtain a second nickel-cobalt precipitate and a second nickel-cobalt leachate, wherein the pH value of the second nickel-cobalt leachate is 7.6-8.2. Thus, by adjusting the pH value, nickel and cobalt elements are separated from the cobalt-nickel leachate in the form of precipitation through solid-liquid separation to achieve the extraction of nickel and cobalt elements.

[0018] In some embodiments, the method further comprises: mixing the second nickel-cobalt precipitate with the high-pressure leaching solution, thereby recovering the oxidant and the unseparated metal elements.

[0019] In some embodiments, the method further comprises: introducing air into the high-pressure leaching solution, thereby further oxidizing the high-pressure leaching solution.

[0020] In some embodiments, the method further comprises: introducing air into the iron-removing aluminum leaching solution, thereby further oxidizing the iron-removing aluminum leaching solution. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0022] Figure 1 This is a schematic diagram of the process of preparing high-pressure leaching solution and nickel-cobalt products according to one embodiment of the present application. DETAILED DESCRIPTION

[0023] The embodiments of the present application are described in detail below. Examples of the embodiments are shown in the drawings, but unnecessary detailed descriptions may be omitted. For example, detailed descriptions of well-known matters and repeated descriptions of actually identical structures may be omitted. This is to avoid the following description from becoming unnecessarily lengthy and to facilitate understanding by those skilled in the art. In addition, the drawings and the following description are provided for those skilled in the art to fully understand the present application and are not intended to limit the subject matter described in the claims.

[0024] Unless otherwise defined, all technical and scientific terms used in this application have the same meanings as those commonly understood by technicians in the technical field to which this application belongs; the terms used in this application are only for the purpose of describing specific embodiments and are not intended to limit this application; unless otherwise specified, the numerical values ​​of the parameters mentioned in this application can be measured using various measurement methods commonly used in the art (for example, they can be tested according to the methods given in the embodiments of this application).

[0025] The terms "including" and "having" in the specification and claims of the present application and any modifications thereof are open expressions, that is, including the contents specified in the present application but not excluding other contents.

[0026] In the description of this application, regardless of whether the words "about" or "approximately" are used, all the numbers disclosed herein are approximate values. The value of each number may differ by less than 10% or a reasonable difference considered by those skilled in the art, such as 1%, 2%, 3%, 4% or 5%.

[0027] "Scope" disclosed in the present application is limited in the form of lower limit and upper limit, and a given range is limited by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundary of a special range. The scope limited in this way can be including end values ​​or not including end values, and can be arbitrarily combined, that is, any lower limit can be combined with any upper limit to form a scope. For example, if the scope of 60-120 and 80-110 is listed for a specific parameter, it is understood that the scope of 60-110 and 80-120 is also expected. In addition, if the minimum range values ​​1 and 2 are listed, and if the maximum range values ​​3, 4 and 5 are listed, the following scope can be all expected: 1-3, 1-4, 1-5, 2-3, 2-4 and 2-5. In the present application, unless otherwise specified, the numerical range "ab" represents the abbreviation of any real number combination between a and b, wherein a and b are real numbers. For example, the numerical range "0-5" means that all real numbers between "0-5" are listed in this document, and "0-5" is just an abbreviation of these numerical combinations. In addition, when a parameter is expressed as an integer ≥ 2, it is equivalent to disclosing that the parameter is, for example, an integer of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0028] Unless otherwise specified, all embodiments and optional embodiments of the present application can be combined with each other to form a new technical solution.

[0029] Unless otherwise specified, all technical features and optional technical features of this application can be combined with each other to form a new technical solution.

[0030] The reductive laterite nickel ore smelting process includes two major directions: pyrometallurgy and hydrometallurgy. In the hydrometallurgy process, compared with ammonia leaching and atmospheric pressure acid leaching, high pressure acid leaching (HPAL) has a higher recovery rate for nickel and cobalt, and is the mainstream direction of the development of the hydrometallurgy. HPAL generally uses dilute sulfuric acid as the leaching solvent. Under a high temperature and high pressure environment of about dozens of times the standard atmospheric pressure, by adjusting the process parameters, the nickel and cobalt in the raw material slurry enter the leaching solvent to form a leachate, and then the subsequent neutralization and impurity removal precipitation obtains nickel cobalt hydroxide (MHP) or nickel cobalt sulfide (MSP), and most of the iron and silicon are formed into slag through the post-treatment process. After years of development, the HPAL process has improved the recovery rate of nickel and cobalt in the whole process, but a large amount of oxidant needs to be added in the recovery process of the leachate to achieve the recovery of nickel and cobalt, which makes the production cost high. At the same time, the laterite nickel ore leachate also contains a large amount of iron and manganese elements, which are also worth recycling. Only simple sediment treatment not only consumes a lot of sedimentation agents, resulting in increased production costs, but also fails to fully utilize resources. The method proposed by the present invention can reduce the addition of auxiliary agents in the production process and realize the recovery of oxidants, so as to reduce production costs and improve the utilization ratio of metal elements in the reducing laterite ore.

[0031] In a first aspect of the present application, the present application proposes a method for preparing a high-pressure leaching solution, comprising: subjecting a reduced laterite nickel ore slurry to a high-pressure acid leaching treatment to obtain a high-pressure leaching solution, wherein the reduced laterite nickel ore slurry and an oxidant are mixed before the high-pressure acid leaching treatment, and / or the oxidant is added during the high-pressure acid leaching treatment.

[0032] The reduced laterite nickel ore contains reducing substances such as organic matter and ferrous ions. At the same time, affected by the origin and grade of the laterite nickel ore, the content of reducing substances and the content of metal elements such as cobalt and nickel will also vary within a certain range. The method for preparing a high-pressure leaching solution introduces an oxidant before and / or during high-pressure acid leaching. The oxidant can react with the reducing impurities contained in the reduced laterite nickel ore slurry and fully oxidize the low-valent metal ions to a high-valent state, so that the metal elements in the prepared high-pressure leaching solution are more fully oxidized. Among them, the iron element contained in the reduced laterite nickel ore slurry can enter the high-pressure leaching solution in the form of divalent iron and trivalent iron during the high-pressure leaching process. The reaction of the iron element entering the high-pressure leaching solution includes: 2FeO(OH)+3H2SO4→Fe2(SO4)3+4H2O, FeO+H2SO4→FeSO4+H2O. Among them, most of the trivalent iron is further converted into Fe2O3 in the autoclave and enters the slag. The main reaction is: Fe2(SO4)3+3H2O→Fe2O3+3H2SO4. However, the divalent iron cannot be precipitated into the slag in the autoclave, and all the divalent iron in the leachate is retained in the liquid phase and enters the subsequent process. Therefore, the oxidation of divalent iron in the high-pressure acid leaching reaction stage can reduce the content of divalent iron ions in the high-pressure leachate, thereby reducing the total iron ion content in the high-pressure leachate.

[0033] In the subsequent process of separating elements such as cobalt, nickel, and iron, the precipitation pH range of trivalent iron ions is lower than that of divalent iron ions, and it can precipitate to form iron hydroxide at a relatively low pH value, thereby achieving separation from valuable metals such as nickel and cobalt; while the precipitation pH value of divalent iron ions is close to that of valuable metal ions such as nickel and cobalt, and it is impossible to achieve separation from valuable metals such as nickel and cobalt by adjusting the pH value. Therefore, the high-cost oxidant such as hydrogen peroxide needs to be added to the high-pressure leaching liquid out of the autoclave in the neutralization process to convert divalent iron into trivalent iron and remove it. However, this will increase the amount of iron hydroxide in the system, increase the consumption of neutralizers, and affect the sedimentation and filtration performance of the slurry, thereby affecting the production efficiency of equipment such as thickeners and filter presses, and increasing production costs.

[0034] In some embodiments, the high-pressure leaching solution includes sulfuric acid with a mass concentration of 15 g / L-60 g / L.

[0035] In some embodiments, the dry weight ratio of the oxidant to the reduced laterite nickel ore slurry is less than or equal to 0.05. The dry weight ratio is the dry basis mass ratio of the oxidant to the reduced laterite nickel ore slurry. Within the aforementioned dry weight ratio range, the addition of the oxidant can achieve an oxidation effect, so that the oxidant in the prepared high-pressure leaching solution is reacted as much as possible, and the waste of the oxidant is reduced.

[0036] In some embodiments, the average valence of the manganese element in the oxidant is higher than +2. Thus, the manganese element that plays an oxidizing role has a strong oxidizing ability as a whole, and a unit amount of manganese element can oxidize more divalent iron, reducing the amount of oxidant added to achieve a better oxidation effect. The manganese element can be precipitated by pH control in the subsequent treatment to achieve the recovery of the manganese element, thereby reducing the comprehensive cost on the oxidant, which helps to reduce production costs.

[0037] In some embodiments, the molar proportion of tetravalent manganese in the manganese element in the oxidant is greater than or equal to 90%. Thus, the oxidant can fully exert its oxidizing effect, further improve the utilization rate of the oxidant, and reduce the oxidation cost.

[0038] In some embodiments, the oxidant includes at least one of pyrolusite and manganite. The use and treatment process of the manganese-containing mineral as the oxidant is simple, wherein the manganese element includes tetravalent manganese, which has strong oxidizing properties and can achieve a good oxidation effect. At the same time, the manganese element can be recycled and reused in the subsequent processing process.

[0039] In some embodiments, the particle size of the oxide is less than or equal to 3 mm, thereby facilitating a relatively fast and controllable oxidation reaction.

[0040] In some embodiments, in the high pressure acid leaching treatment, the amount of sulfuric acid added per 1000 kg of reduced laterite nickel ore slurry is 180 kg-450 kg. Within the above range, there is sufficient sulfuric acid in the reactor for high pressure acid leaching treatment, and a relatively stable acidic environment and sulfuric acid concentration can be maintained during the leaching of elements such as cobalt and nickel in the reduced laterite nickel ore slurry, which is conducive to the stable and continuous leaching of metal elements.

[0041] In some embodiments, the temperature of the high-pressure acid leaching treatment is 240°C-280°C, and the pressure of the high-pressure acid leaching treatment is 3.0MPa-6.0MPa. Within the aforementioned temperature and pressure range, the nickel and cobalt elements in the reduced laterite nickel ore slurry enter the high-pressure leaching solution in the form of metal ions to form metal sulfates for subsequent precipitation and recovery. The reactions of nickel and cobalt elements entering the high-pressure leaching solution include: NiO+H2SO4→NiSO4+H2O, Co2O3+2FeSO4+3H2SO4→2CoSO4+Fe2(SO4)3+3H2O.

[0042] In some embodiments, the high pressure acid leaching treatment time is 0.5h-2h. Within the aforementioned time range, the leaching process of nickel and cobalt elements in the reduced laterite nickel ore slurry can be fully completed and mixed in the high pressure leaching solution in the form of metal salts.

[0043] In some embodiments, the content of divalent iron ions in the high-pressure leaching solution obtained after the high-pressure acid leaching treatment is less than or equal to 1.5 g / L. As a result, the total content of iron ions in the high-pressure leaching solution is reduced, the consumption of neutralizing agent is reduced, and the sedimentation and filtration performance of the slurry are improved, thereby improving the production efficiency of equipment such as thickeners and filter presses and reducing production costs.

[0044] In the second aspect of the present application, the present application proposes a method for preparing nickel cobalt hydroxide, wherein a high-pressure leachate is subjected to an iron-aluminum removal treatment to obtain an iron-aluminum precipitate and an iron-aluminum removal leachate, wherein the high-pressure leachate is prepared by the method proposed in the present application; the iron-aluminum removal leachate is subjected to a nickel-cobalt precipitation treatment to obtain a nickel-cobalt product and a nickel-cobalt leachate, wherein the nickel-cobalt product includes nickel cobalt hydroxide.

[0045] In the high-pressure leachate prepared by the method proposed in the present application, the content of divalent iron ions is relatively small, and thus by adjusting the pH value of the high-pressure leachate, for example, adding an alkaline neutralizing agent to carry out iron-aluminum removal treatment, and controlling its pH value within the precipitation range of trivalent iron ions and aluminum ions, the iron and aluminum metals in the reduced laterite nickel ore can be removed well. Further, an alkaline neutralizing agent is added to the iron-aluminum removal leachate obtained by the iron-aluminum removal treatment to carry out nickel-cobalt precipitation treatment. Because the oxidant has relatively fully oxidized the ferrous ions in the high-pressure leachate to trivalent ferrous ions, the nickel-cobalt precipitation treatment stage is reduced, and the phenomenon of co-precipitation of ferrous ions and cobalt and nickel ions due to the close precipitation pH value of ferrous ions, thereby reducing the iron content in the nickel-cobalt precipitation and improving the purity of the nickel-cobalt precipitation. Therefore, by continuing to add the alkaline neutralizing agent and changing the pH value of the iron and aluminum removal leaching solution, the cobalt and nickel elements reach the precipitation pH range and then precipitate to obtain the nickel-cobalt product, thereby realizing the extraction of nickel and cobalt elements in the reduced laterite nickel ore, improving the purity of the prepared nickel-cobalt product, and reducing the difficulty and cost of subsequent treatment of the nickel-cobalt product.

[0046] In some embodiments, the method further comprises: pre-neutralizing the high-pressure leaching solution so that the pH value of the high-pressure leaching solution is 1.5-2.0. Thus, by adding an alkaline neutralizing agent, the sulfuric acid in the high-pressure leaching solution can be partially neutralized, so that the acidity of the high-pressure leaching solution is reduced and is closer to the pH value of the iron and aluminum removal treatment, making it easier to adjust the pH value of the subsequent iron and aluminum removal treatment, which helps to control the change process of the pH value of the high-pressure leaching solution more accurately.

[0047] In some embodiments, the neutralizing agent that can be used in the pre-neutralization treatment includes at least one of quicklime and calcium carbonate.

[0048] In some embodiments, the pre-neutralization treatment, iron and aluminum removal treatment, and nickel and cobalt precipitation treatment can all be separated into solid and liquid by a thickener.

[0049] In some embodiments, the iron-aluminum removal treatment includes a first iron-aluminum removal treatment and a second iron-aluminum removal treatment, wherein the first iron-aluminum removal treatment is performed on the high-pressure leachate to obtain a first iron-aluminum precipitate and a first iron-aluminum removal leachate, wherein the pH value of the first iron-aluminum removal leachate is 3.5-4.0; the second iron-aluminum removal treatment is performed on the first iron-aluminum removal leachate to obtain a second iron-aluminum precipitate and a second iron-aluminum removal leachate, wherein the pH value of the second iron-aluminum removal leachate is 4.5-5.0.

[0050] Thus, by further subdividing the pH value control process in the iron and aluminum removal process, iron and aluminum precipitation and iron and aluminum removal leachate can be obtained at multiple pH value stages. Because different metal ions reach the maximum precipitation efficiency at different pH values, the components of the iron and aluminum precipitation and iron and aluminum removal leachate at different stages may be different, which is conducive to controlling the components of the precipitation, so that elements such as iron and aluminum can be collected more accurately and more completely, so that the iron and aluminum elements are separated from the iron and aluminum removal leachate in the form of precipitation through solid-liquid separation to achieve the removal of iron and aluminum elements.

[0051] In some embodiments, the content of divalent iron ions in the second iron-removing aluminum leachate is less than or equal to 0.01 g / L.

[0052] In some embodiments, the neutralizing agent used in the iron and aluminum removal treatment includes at least one of quicklime, calcium carbonate, sodium hydroxide, and potassium hydroxide.

[0053] In some embodiments, the second iron removal and aluminum precipitation is mixed with the high pressure leaching solution to recover the nickel and cobalt elements precipitated in the second iron removal and aluminum removal process, thereby improving the overall nickel and cobalt recovery rate.

[0054] In some embodiments, the nickel-cobalt precipitation treatment includes a first nickel-cobalt precipitation treatment and a second nickel-cobalt precipitation treatment, wherein the iron-aluminum-removing leaching solution is subjected to a first nickel-cobalt precipitation treatment to obtain the nickel-cobalt product and a first nickel-cobalt leaching solution, wherein the pH value of the first nickel-cobalt leaching solution is 7.0-7.6; the first nickel-cobalt leaching solution is subjected to a second nickel-cobalt precipitation treatment to obtain a second nickel-cobalt precipitate and a second nickel-cobalt leaching solution, wherein the pH value of the second nickel-cobalt leaching solution is 7.6-8.2.

[0055] After the iron and aluminum removal treatment, the pH value is adjusted by continuing to add a neutralizer so that the pH value changes to the precipitation pH range of cobalt and nickel elements. By controlling the range of pH value changes, the nickel and cobalt precipitation treatment can be divided into multiple stages, such as the first nickel and cobalt precipitation treatment and the second nickel and cobalt precipitation treatment, so that cobalt and nickel elements can be precipitated in the form of hydroxides and separated from the nickel and cobalt leaching solution through solid-liquid separation to achieve the extraction of nickel and cobalt elements.

[0056] In some embodiments, the method may further include: subjecting the nickel-cobalt leaching solution to manganese precipitation treatment. By further adding an alkaline neutralizing agent, the pH value of the nickel-cobalt leaching solution is adjusted to 6.0-12.0, so that manganese elements are precipitated and can be separated and recovered, and can be sold as a by-product after recovery, thereby reducing the production cost of producing nickel-cobalt products.

[0057] In some embodiments, the method may further include: mixing the second nickel-cobalt precipitate with the high-pressure leaching solution. Since the second nickel-cobalt precipitate may contain a certain amount of oxidizing manganese elements, mixing the second nickel-cobalt precipitate with the high-pressure leaching solution can not only allow the manganese elements therein to oxidize the reducing substances that may remain in the high-pressure leaching solution, but also recover the unseparated nickel and cobalt elements in the second nickel-cobalt precipitate. Thus, the second nickel-cobalt precipitate can be subjected to another round of treatment to prepare nickel-cobalt hydroxide, thereby improving the overall recovery rate of metal elements.

[0058] In some embodiments, the method may further include: introducing air into the high-pressure leaching solution, so that oxygen in the air can be used as an oxidant to further oxidize the high-pressure leaching solution, thereby reducing the content of reducing substances in the high-pressure leaching solution.

[0059] In some embodiments, the method may further include: introducing air into the de-ironification and de-aluminumization leachate, so that the oxygen in the air can further oxidize the de-ironification and de-aluminumization leachate, thereby reducing the content of reducing substances in the de-ironification and de-aluminumization leachate, which is beneficial to the precipitation of iron elements.

[0060] The scheme of the present application is described below by specific examples. It should be noted that the following examples are only used to illustrate the present application and should not be considered as limiting the scope of the present application. If no specific technology or conditions are specified in the examples, the technology or conditions described in the literature in this area or the product instructions are used. The reagents or instruments used are not specified by the manufacturer, and are all conventional products that can be obtained commercially.

[0061] Example 1

[0062] A certain reducing laterite nickel ore pulp was subjected to high-pressure acid leaching treatment, wherein the reaction temperature was 250°C, the reaction pressure was 4.6MPa, the reaction time was 1 hour, and the acid-ore ratio was 300kg / t dry ore; an oxidant was added to the feed slurry of the autoclave, wherein the oxidant was pyrolusite with a manganese content of 40% and tetravalent manganese accounting for 95% of the total manganese, and the amount of the oxidant added was 15kg / t dry ore.

[0063] The ferrous ion content in the prepared high-pressure leaching solution is 1.2 g / L.

[0064] The prepared high-pressure leaching solution was treated to remove iron and aluminum, and no ferrous ions were detected in the obtained iron- and aluminum-removed leaching solution.

[0065] Comparative Example 1

[0066] Comparative Example 1 is consistent with Example 1, except that no oxidant is added during the high pressure acid leaching treatment. The ferrous ion content in the prepared high pressure leaching solution is 6.2 g / L.

[0067] Example 2

[0068] A certain reducing laterite nickel ore pulp was subjected to high-pressure acid leaching treatment, wherein the reaction temperature was 250°C, the reaction pressure was 4.6MPa, the reaction time was 1 hour, and the acid-ore ratio was 330kg / t dry ore; an oxidant was added to the feed slurry of the autoclave, wherein the oxidant was pyrolusite with a manganese content of 45% and tetravalent manganese accounting for 95% of the total manganese, and the amount of the oxidant added was 13kg / t dry ore.

[0069] The ferrous ion content in the prepared high-pressure leaching solution is 0.9 g / L.

[0070] The prepared high-pressure leaching solution was subjected to iron and aluminum removal treatment, and no ferrous ions were detected in the obtained iron and aluminum removal leaching solution.

[0071] Comparative Example 2

[0072] Comparative Example 2 is consistent with Example 2, except that no oxidant is added during the high pressure acid leaching treatment. The ferrous ion content in the prepared high pressure leaching solution is 5.7 g / L.

[0073] In the description of the present application, “plurality” means two or more.

[0074] In the description of the present application, "A and / or B" may include the case of A alone, the case of B alone, or any of the cases of A and B, where A and B are only used for examples and may be any technical feature connected by "and / or" in the present application.

[0075] In the present application, the writing order of each step does not mean a strict execution order and does not constitute any limitation on the implementation process. The specific execution order of each step should be determined by its function and possible internal logic. If there is no special explanation, all steps of the present application can be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, or may include steps (b) and (a) performed sequentially. For example, the method may also include step (c), indicating that step (c) can be added to the method in any order, for example, the method may include steps (a), (b) and (c), or may include steps (a), (c) and (b), or may include steps (c), (a) and (b), etc.

[0076] It should be noted that the present application is not limited to the above-mentioned embodiments. The above-mentioned embodiments are only examples, and the embodiments having the same structure as the technical idea and exerting the same effect within the scope of the technical solution of the present application are all included in the technical scope of the present application. In addition, without departing from the scope of the main purpose of the present application, various modifications that can be thought of by those skilled in the art to the embodiments and other methods of combining some of the constituent elements in the embodiments are also included in the scope of the present application.

Claims

1. A method for preparing a high-pressure leaching solution, characterized in that: include: The reduced laterite nickel ore slurry is subjected to high pressure acid leaching to obtain a high pressure leaching solution. Wherein, the reducing laterite nickel ore slurry and the oxidant are mixed before the high pressure acid leaching treatment, and / or the oxidant is added during the high pressure acid leaching treatment.

2. The method according to claim 1, characterized in that The high-pressure leaching solution comprises sulfuric acid with a mass concentration of 15 g / L-60 g / L; and / or, The dry weight ratio of the oxidant to the reduced laterite nickel slurry is less than or equal to 0.05; and / or, The average valence of the manganese element in the oxidant is higher than +2.

3. The method according to claim 2, characterized in that The molar proportion of tetravalent manganese in the manganese element in the oxidant is greater than or equal to 90%; and / or, The oxidant comprises at least one of pyrolusite and manganite; and / or, The particle size of the oxidant is less than or equal to 3 mm.

4. The method according to claim 1 or 2, characterized in that: The temperature of the high pressure acid leaching treatment is 240°C-280°C. The pressure of the high pressure acid leaching treatment is 3.0 MPa-6.0 MPa; and / or, The high pressure acid leaching treatment time is 0.5h-2h.

5. A method for preparing nickel cobalt hydroxide, characterized in that: The high-pressure leaching solution is subjected to a de-iron-aluminum treatment to obtain an iron-aluminum precipitate and a de-iron-aluminum leaching solution, wherein the high-pressure leaching solution is prepared by the method according to any one of claims 1 to 4; The iron-removed aluminum leaching solution is subjected to nickel-cobalt precipitation treatment to obtain a nickel-cobalt product and a nickel-cobalt leaching solution, wherein the nickel-cobalt product includes nickel-cobalt hydroxide.

6. The method according to claim 5, characterized in that Further including: The high-pressure leaching solution is pre-neutralized to make the pH value of the high-pressure leaching solution be 1.5-2.

0.

7. The method according to claim 5 or 6, characterized in that: The iron removal and aluminum removal treatment includes a first iron removal and aluminum removal treatment and a second iron removal and aluminum removal treatment, wherein: Performing the first iron-aluminum removal treatment on the high-pressure leachate to obtain a first iron-aluminum precipitate and a first iron-aluminum removal leachate, wherein the pH value of the first iron-aluminum removal leachate is 3.5-4.0; The first iron-removal aluminum leachate is subjected to the second iron-removal aluminum treatment to obtain a second iron-aluminum precipitate and a second iron-removal aluminum leachate, wherein the pH value of the second iron-removal aluminum leachate is 4.5-5.

0.

8. The method according to claim 5 or 6, characterized in that: The nickel-cobalt precipitation treatment includes a first nickel-cobalt precipitation treatment and a second nickel-cobalt precipitation treatment, wherein: Performing a first nickel-cobalt precipitation treatment on the iron-removed aluminum leaching solution to obtain the nickel-cobalt product and a first nickel-cobalt leaching solution, wherein the pH value of the first nickel-cobalt leaching solution is 7.0-7.6; The first nickel-cobalt leaching solution is subjected to a second nickel-cobalt precipitation treatment to obtain a second nickel-cobalt precipitate and a second nickel-cobalt leaching solution, wherein the pH value of the second nickel-cobalt leaching solution is 7.6-8.

2.

9. The method according to claim 8, characterized in that Further including: The second nickel-cobalt precipitate is mixed with the high-pressure leaching solution.

10. The method according to claim 5 or 6, characterized in that: Further including: introducing air into the high-pressure leaching solution; and / or, Air is introduced into the iron-removing aluminum leaching solution.

Images