A nickel-cobalt hydroxide slurry leaching apparatus and leaching method

Abstract

This invention provides a nickel-cobalt hydroxide slurry leaching apparatus and method. The nickel-cobalt hydroxide slurry leaching method includes: separately conveying nickel-cobalt hydroxide material and a mixed liquid to a slurry preparation tank for slurry preparation to obtain a homogenized slurry; subsequently, leaching the homogenized slurry to obtain a leachate, and recirculating a portion of the leachate back to the slurry preparation process; the slurry preparation includes sequential primary and secondary agitated slurry preparation, with the primary agitated slurry preparation rate being lower than the secondary agitated slurry preparation rate; the liquid-to-solid ratio in the slurry preparation tank is (1~1.5):1. This invention achieves high-speed, continuous slurry preparation by optimizing the slurry preparation process and process parameters, greatly improving the uniformity and stability of the slurry.

Description

Technical Field

[0001] This invention belongs to the field of hydrometallurgical technology, and relates to hydrometallurgical refining of nickel, and particularly to a nickel-cobalt hydroxide slurry leaching apparatus and leaching method. Background Technology

[0002] Hydrometallurgical processes are typically conducted under low-temperature and low-pressure conditions, enabling highly selective leaching and separation of specific metals. This method is effective for recovering metal elements from low-grade ores, complex polymetallic ores, and lateritic nickel ores. Nickel-cobalt hydroxide (MHP) is an intermediate product of lateritic nickel ore hydrometallurgy and an important precursor for battery materials. In nickel refining, MHP needs to be pulped, selectively precipitated, and then impurities removed to extract the useful metals.

[0003] CN109797283A discloses a hydrochloric acid leaching method for silicon-containing nickel-cobalt hydroxide. The method involves slurrying, pre-leaching, and pressure filtration of silicon-containing nickel-cobalt hydroxide with sodium hydroxide solution to obtain pre-leaching filtrate and desiliconized nickel-cobalt hydroxide. These are then subjected to industrial water washing and hydrochloric acid leaching in sequence, which improves the nickel leaching rate and ensures the appearance quality of the electrolytic nickel products produced in the electrolytic nickel production system.

[0004] CN118726761A discloses a method for selective leaching of nickel-cobalt hydroxide to remove impurities. The method involves preparing a slurry of nickel-cobalt hydroxide raw material, then sequentially adding acid and nickel-cobalt hydroxide to adjust the pH value. This is followed by multiple acid leaching processes and pH adjustments, and the addition of a reducing agent to obtain the desired leachate and leaching residue. This method reduces metal loss in solid waste residue and improves metal recovery rate.

[0005] CN111826523A discloses a method for refining nickel-cobalt hydroxide. The method involves preparing nickel-cobalt hydroxide into a slurry, heating it, adding an acid solution to adjust the pH, reacting to obtain a pre-impregnated slurry, and then repeatedly adding an alkaline solution to adjust the pH, reacting, and filtration to obtain a nickel sulfate solution. This method optimizes the smelting of nickel-cobalt hydroxide with high efficiency, reduces the loss rate of nickel, cobalt, and manganese and the introduction of impurity elements, reduces energy consumption, and lowers production costs.

[0006] However, existing nickel-cobalt hydroxide pulping processes suffer from poor micro-dispersion of materials, leading to agglomeration, decreased pulp consistency, and reduced pulping quality and efficiency. Furthermore, continuous production is difficult to achieve for systems with large density differences or wide particle size distributions, increasing process complexity, poor controllability, and high energy consumption. Therefore, it is necessary to optimize the pulping process and overcome the bottlenecks of existing nickel-cobalt hydroxide pulping methods. Summary of the Invention

[0007] To address the shortcomings of existing technologies, the present invention aims to provide a nickel-cobalt hydroxide slurry leaching device and leaching method. By optimizing the slurry preparation process and process parameters, high-speed and continuous slurry preparation is achieved, resulting in a uniform and stable slurry, which provides a strong guarantee for efficient leaching in subsequent processes.

[0008] To achieve this objective, the present invention adopts the following technical solution: In a first aspect, the present invention provides a method for slurry leaching of nickel-cobalt hydroxide, the method comprising: conveying nickel-cobalt hydroxide material and a mixed liquid to a slurry tank for slurry preparation to obtain a homogenized slurry; subsequently leaching the homogenized slurry to obtain a leachate, and returning a portion of the leachate to the slurry preparation process.

[0009] The pulping process includes a first-stage agitated pulping and a second-stage agitated pulping performed sequentially, wherein the speed of the first-stage agitated pulping is less than the speed of the second-stage agitated pulping.

[0010] The liquid-to-solid ratio in the pulping tank is (1~1.5):1, for example, it can be 1.00:1, 1.05:1, 1.10:1, 1.15:1, 1.20:1, 1.25:1, 1.30:1, 1.35:1, 1.40:1, 1.45:1 or 1.50:1, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0011] As a preferred embodiment of the present invention, the conveying flow rate of the nickel-cobalt hydroxide material is 20t / h to 25t / h, for example, it can be 20t / h, 20.5t / h, 21t / h, 21.5t / h, 22t / h, 22.5t / h, 23t / h, 23.5t / h, 24t / h, 24.5t / h or 25t / h, but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0012] As a preferred embodiment of the present invention, the pulping process takes 8 to 10 minutes, for example, 8 minutes, 8.5 minutes, 9 minutes, 9.5 minutes or 10 minutes, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0013] The homogenized slurry concentration is 20% to 25%, for example, it can be 20%, 20.5%, 21%, 21.5%, 21.8%, 22%, 22.5%, 22.7%, 23%, 23.5%, 23.6%, 24%, 24.5% or 25%, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0014] The viscosity of the homogenized slurry is 14cp to 35cp, for example, it can be 14cp, 15cp, 16cp, 20cp, 23cp, 25cp, 28cp, 30cp, 32cp or 35cp, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable, preferably 25 to 35cp.

[0015] As a preferred embodiment of the present invention, a portion of the leachate is recycled to the primary stirring and slurrying process.

[0016] In the mixture, the proportion of the leachate returned to the primary stirred pulping process is 50% to 55%, for example, it can be 50%, 51%, 52%, 53%, 54% or 55%, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0017] As a preferred embodiment of the present invention, the speed of the primary stirring and slurrying is 200 r / min to 250 r / min, for example, it can be 200 r / min, 205 r / min, 210 r / min, 215 r / min, 220 r / min, 225 r / min, 230 r / min, 235 r / min, 240 r / min, 245 r / min or 250 r / min, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0018] The speed of the secondary stirring and slurrying is 350 r / min to 450 r / min, for example, it can be 350 r / min, 355 r / min, 360 r / min, 370 r / min, 380 r / min, 390 r / min, 400 r / min, 410 r / min, 420 r / min, 430 r / min, 440 r / min or 450 r / min, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0019] In a second aspect, the present invention provides a nickel-cobalt hydroxide slurry leaching apparatus for the nickel-cobalt hydroxide slurry leaching method described in the first aspect. The nickel-cobalt hydroxide slurry leaching apparatus includes a feeding assembly, a slurry preparation tank, a slurry storage tank, and a leaching tank connected sequentially along the material direction. The leaching tank is also connected to the slurry preparation tank.

[0020] The pulping tank is equipped with a homogenizing and stirring assembly and a disperser.

[0021] The homogenizing and stirring assembly is located on the central axis of the slurry tank and is used for primary stirring and slurrying of the material.

[0022] The disperser includes an inner tank, which is disposed on the inner side wall of the pulping tank. After primary stirring and pulping, the material flows upward into the inner tank.

[0023] The inner tank is equipped with a dispersion and stirring assembly for secondary stirring and slurrying of materials.

[0024] The inner tank is also provided with an overflow port, which is connected to the slurry storage tank.

[0025] As a preferred embodiment of the present invention, the feeding assembly includes a shaftless screw conveyor, and the inlet end of the shaftless screw conveyor is further provided with a metering component for weighing the material.

[0026] As a preferred embodiment of the present invention, a first flow meter is provided on the connecting pipeline between the leaching tank and the pulping tank.

[0027] The pulping tank is provided with a washing liquid inlet, and a second flow meter is installed at the washing liquid inlet.

[0028] The first flow meter and the second flow meter are independently electrically connected to the metering component.

[0029] This invention weighs the feed material and controls the flow rate of the mixed liquor and the flow rate of the reflux leachate. At the same time, it interlocks the metering component with the flow detection to control the liquid-solid ratio and pulping time, ensuring uniform and stable pulp concentration, thereby obtaining high-quality pulp.

[0030] As a preferred embodiment of the present invention, the homogenizing and stirring assembly includes a first driving component, a first rotating shaft, and stirring blades.

[0031] The first drive unit is located at the top of the pulping tank and is connected to the first rotating shaft. The first rotating shaft extends into the inner cavity of the pulping tank, and the stirring blade is provided at the end of the first rotating shaft away from the first drive unit.

[0032] The stirring blades include two cross-arranged guide blades.

[0033] The dispersion and stirring assembly includes a second drive element, a second rotating shaft, and at least one dispersion disc.

[0034] The second driving member is located at the top of the inner tank and is connected to the second rotating shaft. The second rotating shaft extends into the inner cavity of the inner tank, and the dispersing disk is provided at the end of the second rotating shaft away from the second driving member.

[0035] The dispersion disk includes a dispersion body, on which a plurality of upper guide protrusions and a plurality of lower guide protrusions are provided. The protrusion directions of the upper guide protrusions and the lower guide protrusions are opposite, and the upper guide protrusions and the lower guide protrusions are alternately arranged along the circumference of the dispersion body.

[0036] As a preferred embodiment of the present invention, the volume ratio of the pulping tank to the inner tank is (25~40):1, for example, it can be 25:1, 27:1, 28:1, 30:1, 32:1, 34:1, 35:1, 36:1, 38:1 or 40:1, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0037] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention employs multi-stage stirring and slurry preparation of nickel-cobalt hydroxide, and optimizes process parameters to avoid problems such as insufficient stirring and residual particulate impurities in the slurry. This improves the uniformity of the slurry, ensuring efficient leaching in subsequent processes and increasing leaching efficiency. At the same time, some of the generated leachate is reused, improving material utilization, reducing material consumption, and lowering slurry preparation costs. Attached Figure Description

[0038] Figure 1 This is a schematic diagram of the pulping tank provided in Example 1.

[0039] Figure 2 This is a schematic diagram of the structure of the first rotating shaft and the stirring component provided in Example 1.

[0040] Figure 3 This is a schematic diagram of the guide vane provided in Example 1.

[0041] Figure 4 This is a schematic diagram of the inner tank provided in Example 1.

[0042] Figure 5 This is a schematic diagram of the structure of the dispersion disk provided in Example 1.

[0043] Figure 6 The flowchart is for the nickel-cobalt hydroxide slurry leaching method provided in Example 1.

[0044] Among them, 1-slurry tank; 2-shaftless screw conveyor; 3-first rotating shaft; 4-guide vane; 5-inner tank body; 6-second rotating shaft; 7-dispersion disc; 71-dispersion body; 72-upper guide protrusion; 73-lower guide protrusion; 8-overflow port. Detailed Implementation

[0045] It should be understood that in the description of this invention, the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0046] It should be noted that, in the description of this invention, unless otherwise explicitly specified and limited, the terms "set," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0047] Those skilled in the art should understand that the present invention necessarily includes the necessary pipelines, conventional valves and general pump equipment for achieving complete process, but the above content is not the main inventive point of the present invention. Those skilled in the art can add layouts based on process flow and equipment structure selection, and the present invention does not make any special requirements or specific limitations in this regard.

[0048] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0049] In one specific embodiment, the present invention provides a method for nickel-cobalt hydroxide slurry leaching, which specifically includes the following steps: Step (1) The nickel-cobalt hydroxide material and the mixed liquid are respectively transported to the pulping tank for pulping treatment to obtain homogenized slurry.

[0050] The nickel-cobalt hydroxide material is first unpacked using a packaging machine, and then injected into a pulping tank at a conveying flow rate of 20t / h to 25t / h. The mixture includes a refluxed leachate and an additional washing solution, which can be tap water and / or process washing water.

[0051] The liquid-to-solid ratio in the slurry tank is (1~1.5):1, which is the ratio of the volume of the mixed liquid (mL) to the mass (g) of nickel-cobalt hydroxide material. If the concentration of nickel-cobalt hydroxide material is too high, it will increase the deposition of nickel and easily lead to pipe blockage; if the concentration of nickel-cobalt hydroxide material is too low, the introduced water will exceed the limit and the required material concentration cannot be met.

[0052] The pulping process takes 8 to 10 minutes to fully mix and homogenize the nickel-cobalt hydroxide material with the mixed solution, thereby improving the stability of the pulp. The homogenized slurry has a concentration of 20% to 25% and a viscosity of 14 to 35 cp, preferably 25 to 35 cp. This avoids high viscosity of the homogenized slurry, which would increase mass transfer resistance and reduce the leaching rate. On the other hand, it also prevents excessively low viscosity, which would reduce leaching efficiency and increase the burden on post-processing.

[0053] The pulping process includes sequential primary and secondary stirring pulping to achieve continuous pulping. The speed of the primary stirring pulping is lower than that of the secondary stirring pulping. The primary stirring pulping process efficiently homogenizes the nickel-cobalt hydroxide material after mixing with the mixed liquid. The secondary stirring pulping process disperses the pulped material at high speed, improving the uniformity of the slurry and thus enhancing the leaching efficiency.

[0054] Specifically, the speed of the primary stirring and slurrying is 200 r / min to 250 r / min, and the speed of the secondary stirring and slurrying is 350 r / min to 450 r / min.

[0055] Step (2) The homogenized slurry is then leached to obtain leachate, and a portion of the leachate is returned to the pulping process.

[0056] The nickel-cobalt hydroxide material contains high concentrations of pollutants such as iron, aluminum, manganese, silicon, and chromium, requiring leaching treatment for subsequent impurity removal before further utilization or preparation. The leaching treatment can be acidic or alkaline, with a pH of 1.0–1.5, a time of 1.5–2 hours, and a temperature of 60–80°C, to ensure the complete dissolution of metal ions in the homogenized slurry.

[0057] Specifically, a portion of the leachate is recycled back to the primary stirred pulping process as a makeup liquid for the preparation of nickel-cobalt hydroxide slurry, achieving internal circulation and reducing the amount of mixed liquor used. The proportion of the leachate recycled back to the primary stirred pulping process in the mixed liquor is 50% to 55%.

[0058] This invention also includes the removal of impurities, such as iron, aluminum, and silicon, from the remaining leachate during the leaching process. Furthermore, the impurity removal methods include, but are not limited to, any one or a combination of at least two of the commonly used precipitation, washing, or adsorption methods in the art. This invention does not specifically limit the operating procedures and process parameters of the above methods; those skilled in the art can adjust them according to actual conditions.

[0059] In another specific embodiment, the present invention provides a nickel-cobalt hydroxide slurry leaching apparatus for the nickel-cobalt hydroxide slurry leaching method described in one embodiment. The apparatus includes a feeding assembly, a slurry preparation tank, a slurry storage tank, and a leaching tank connected sequentially along the material direction. The leaching tank is also connected to the slurry preparation tank. A homogenizing and stirring assembly and a disperser are disposed within the slurry preparation tank. The homogenizing and stirring assembly is located on the central axis of the slurry preparation tank and is used for primary slurry mixing and stirring of the material. The disperser includes an inner tank body disposed on the inner wall of the slurry preparation tank. After primary slurry mixing and stirring, the material flows upwards into the inner tank body. A dispersing and stirring assembly is disposed within the inner tank body for secondary slurry mixing and stirring of the material. The inner tank body also has an overflow port connected to the slurry storage tank to overflow the homogenized slurry into the slurry storage tank.

[0060] The pulping tank is cylindrical or columnar, and is preferably made of stainless steel.

[0061] The volume ratio of the pulping tank to the inner tank is (25~40):1.

[0062] The top of the inner tank is flush with the top of the pulping tank and has a segmented structure, including a first tank and a second tank that are coaxial and connected. The size of the first tank is larger than that of the second tank. The first tank has an overflow channel, and the dispersing and stirring assembly extends into the second tank for secondary stirring and pulping.

[0063] The feeding assembly includes a shaftless screw conveyor that transports nickel-cobalt hydroxide material into the slurry tank at a certain speed. The inlet end of the shaftless screw conveyor is also equipped with a metering component for weighing the material and adjusting the material flow rate.

[0064] A first flow meter is installed on the connecting pipe between the leaching tank and the pulping tank to measure the flow rate of the portion of the leaching solution returning to the pulping tank. The pulping tank has a washing solution inlet, and a second flow meter is installed at the washing solution inlet to measure the flow rate of any additional washing solution added. The first and second flow meters are independently and electrically connected to the metering assembly to adjust the liquid-to-solid ratio of the nickel-cobalt hydroxide material injected into the pulping tank and the mixed solution.

[0065] The homogenizing and stirring assembly includes a first driving component, a first rotating shaft, and stirring blades. The first driving component is located at the top of the slurry tank and is connected to the first rotating shaft, which extends into the inner cavity of the slurry tank. The stirring blades are located at the end of the first rotating shaft away from the first driving component. The stirring blades include two cross-arranged guide vanes. In this invention, the stirring blades are located below the inner tank body to avoid collisions during stirring.

[0066] The dispersion and stirring assembly includes a second drive member, a second rotating shaft, and at least one dispersion disc. The second drive member is located at the top of the inner tank and is connected to the second rotating shaft, which extends into the inner cavity of the inner tank. The dispersion disc is disposed at the end of the second rotating shaft away from the second drive member. Preferably, the number of dispersion discs is at least two, and the at least two dispersion discs are spaced apart along the second rotating shaft.

[0067] The dispersion disk includes a dispersion body, which can be made of sheet metal. The dispersion body has a plurality of upper guide protrusions and a plurality of lower guide protrusions, the upper and lower guide protrusions protruding in opposite directions, and the upper and lower guide protrusions are alternately arranged along the circumference of the dispersion body. The shapes of the upper and lower guide protrusions can be rectangular, trapezoidal, triangular, or other polygonal. In this invention, the edges of the dispersion body can be laser-cut or wire-cut, and then bent to form the upper and lower guide protrusions with opposite directions.

[0068] It should be noted that the nickel-cobalt hydroxide slurry leaching device is also equipped with necessary connecting pipelines and switch control valves. This invention does not impose any special limitations on these. Those skilled in the art should reasonably adjust, add, or delete them according to actual production needs. It should be clarified that new technical solutions generated by deleting some unnecessary connecting pipelines and switch control valves, or replacing single-function switch control valves with multi-function integrated control valves, or using external automatic control systems electrically connected to the switch control valves to control the opening of the corresponding valves, etc., which are common and well-known technical means by those skilled in the art, also fall within the scope of disclosure and protection of this invention.

[0069] Example 1 This embodiment provides a nickel-cobalt hydroxide slurry leaching apparatus and leaching method, wherein the nickel-cobalt hydroxide slurry leaching apparatus includes a shaftless screw conveyor, a slurry tank, a slurry storage tank and a leaching tank connected in sequence along the material direction.

[0070] like Figure 1 As shown, the material inlet of the pulping tank is connected to a shaftless screw conveyor. The inlet end of the shaftless screw conveyor is also equipped with a metering component for weighing the material.

[0071] The pulping tank has a washing liquid inlet for injecting washing liquid, and a second flow meter is installed at the washing liquid inlet. A homogenizing and stirring assembly and a disperser are installed inside the pulping tank. The homogenizing and stirring assembly includes a first drive unit, a first rotating shaft, and stirring blades. The first drive unit is located at the top of the pulping tank and is connected to the first rotating shaft, which extends into the inner cavity of the pulping tank and is positioned on the central axis of the pulping tank. Figure 2 and Figure 3 As shown, a stirring blade is provided at the end of the first rotating shaft away from the first driving member. The stirring blade is composed of two cross-arranged guide vanes. The disperser includes, as shown... Figure 4 The inner tank shown is located on the inner wall of the pulping tank. After primary stirring and pulping, the material rises into the inner tank. The volume ratio of the pulping tank to the inner tank is 1:34. A dispersion and stirring assembly is installed inside the inner tank, including a second drive unit, a second rotating shaft, and two dispersion discs. The second drive unit is located at the top of the inner tank and connected to the second rotating shaft, which extends into the inner cavity of the inner tank and is positioned on its central axis. Figure 5 As shown, two dispersing discs are spaced apart at the end of the second rotating shaft away from the second driving component. Each dispersing disc includes a dispersing body, the surface of which is provided with a plurality of upper guiding protrusions and a plurality of lower guiding protrusions. The upper and lower guiding protrusions protrude in opposite directions and are alternately arranged along the circumference of the dispersing body. An overflow port is also provided in the inner tank, connecting to a slurry storage tank.

[0072] The leaching tank is also connected to the pulping tank via a return branch pipe, and a first flow meter is installed on the return branch pipe. The first flow meter and the second flow meter are independently electrically connected to the metering assembly and are used to adjust the liquid-solid ratio in the pulping tank.

[0073] In this embodiment, the nickel-cobalt hydroxide slurry leaching method is as follows: Figure 6 As shown, the specific steps include the following: (1) The nickel-cobalt hydroxide material is fed into the pulping tank at a flow rate of 23t / h using a shaftless screw conveyor, and washing liquid is injected into the pulping tank. At the same time, part of the leachate in the leaching tank is returned to the pulping tank to ensure that the liquid-solid ratio of the nickel-cobalt hydroxide material in the pulping tank to the mixed liquid is 1.5:1, and the volume ratio of the leachate in the mixed liquid is 55%.

[0074] (2) Start the homogenizing and stirring assembly to perform primary stirring and slurrying, and control the stirring speed to 220 r / min.

[0075] (3) The slurry after primary stirring and pulping flows upward into the inner tank and undergoes secondary stirring and pulping under the stirring of the dispersion stirring component. The stirring speed is controlled at 400 r / min and the total time of the entire stirring and pulping process is 8 min, resulting in a homogenized slurry with a slurry concentration of 20%.

[0076] (4) The homogenized slurry in the inner tank overflows into the slurry storage tank, and then the homogenized slurry is sent into the leaching tank for leaching treatment to obtain leachate, and part of the leachate is returned to the primary stirring and slurrying process.

[0077] The leaching process involves acid-base treatment with a pH of 1.0, a duration of 2 hours, and a temperature of 70°C to ensure that the metal ions in the homogenized slurry are fully dissolved.

[0078] Example 2 This embodiment provides a nickel-cobalt hydroxide slurry leaching apparatus and method, which is the same as that used in Embodiment 1. The nickel-cobalt hydroxide slurry leaching method in this embodiment specifically includes the following steps: (1) The nickel-cobalt hydroxide material is fed into the pulping tank at a flow rate of 25t / h using a shaftless screw conveyor, and washing liquid is injected into the pulping tank. At the same time, part of the leachate in the leaching tank is returned to the pulping tank to ensure that the liquid-solid ratio of the nickel-cobalt hydroxide material in the pulping tank to the mixed liquid is 1.2:1, and the volume ratio of the leachate in the mixed liquid is 53%.

[0079] (2) Start the homogenizing and stirring assembly to perform primary stirring and slurrying, and control the stirring speed to 200 r / min.

[0080] (3) The slurry after primary stirring and pulping flows upward into the inner tank and undergoes secondary stirring and pulping under the stirring of the dispersion stirring component. The stirring speed is controlled at 380 r / min and the total time of the entire stirring and pulping process is 10 min, resulting in a homogenized slurry with a slurry concentration of 22.7%.

[0081] (4) The homogenized slurry in the inner tank overflows into the slurry storage tank, and then the homogenized slurry is sent into the leaching tank for leaching treatment to obtain leachate, and part of the leachate is returned to the primary stirring and slurrying process.

[0082] The leaching process involves acid-base treatment with a pH of 1.0, a duration of 1.5 hours, and a temperature of 80°C to ensure that the metal ions in the homogenized slurry are fully dissolved.

[0083] Example 3 This embodiment provides a nickel-cobalt hydroxide slurry leaching apparatus and method, which is the same as that used in Embodiment 1. The nickel-cobalt hydroxide slurry leaching method in this embodiment specifically includes the following steps: (1) The nickel-cobalt hydroxide material is fed into the pulping tank at a flow rate of 20t / h using a shaftless screw conveyor, and washing liquid is injected into the pulping tank. At the same time, part of the leachate in the leaching tank is returned to the pulping tank to ensure that the liquid-solid ratio of the nickel-cobalt hydroxide material in the pulping tank to the mixed liquid is 1:1, and the volume ratio of the leachate in the mixed liquid is 50%.

[0084] (2) Start the homogenizing and stirring assembly to perform primary stirring and slurrying, and control the stirring speed to 250 r / min.

[0085] (3) The slurry after primary stirring and pulping flows upward into the inner tank and is stirred by the dispersion stirring component for secondary stirring and pulping. The stirring speed is controlled at 450 r / min and the total time of the entire stirring and pulping process is 9 min, resulting in a homogenized slurry with a slurry concentration of 25%.

[0086] (4) The homogenized slurry in the inner tank overflows into the slurry storage tank, and then the homogenized slurry is sent into the leaching tank for leaching treatment to obtain leachate, and part of the leachate is returned to the primary stirring and slurrying process.

[0087] The leaching process involves acid-base treatment with a pH of 1.5, a duration of 2 hours, and a temperature of 70°C to ensure that the metal ions in the homogenized slurry are fully dissolved.

[0088] Example 4 This embodiment provides a nickel-cobalt hydroxide slurry leaching apparatus and leaching method. The difference from Embodiment 1 is that the flow rate of the shaftless screw conveyor conveying the nickel-cobalt hydroxide material is 30t / h, while the rest of the method steps and apparatus are the same as in Embodiment 1.

[0089] Example 5 This embodiment provides a nickel-cobalt hydroxide slurry leaching apparatus and leaching method. The difference from Embodiment 1 is that the flow rate of the shaftless screw conveyor conveying the nickel-cobalt hydroxide material is 18t / h, while the rest of the method steps and apparatus are the same as in Embodiment 1.

[0090] Example 6 This embodiment provides a nickel-cobalt hydroxide slurry leaching apparatus and leaching method. The difference from Embodiment 1 is that the total time of the entire stirring slurry process is 6 minutes, while the remaining methods, steps and apparatus are the same as in Embodiment 1.

[0091] Example 7 This embodiment provides a nickel-cobalt hydroxide slurry leaching apparatus and leaching method. The difference from Embodiment 1 is that the volume ratio of the leaching solution in the mixed solution is 45%, while the remaining method steps and apparatus are the same as in Embodiment 1.

[0092] Example 8 This embodiment provides a nickel-cobalt hydroxide slurry leaching apparatus and leaching method. The difference from Embodiment 1 is that the volume ratio of the leaching solution in the mixed solution is 60%, while the remaining method steps and apparatus are the same as in Embodiment 1.

[0093] Comparative Example 1 This comparative example provides a nickel-cobalt hydroxide slurry leaching apparatus and leaching method. The difference from Example 1 is that the liquid-solid ratio of nickel-cobalt hydroxide material to the mixed solution is 2:1, while the remaining method steps and apparatus are the same as in Example 1.

[0094] Comparative Example 2 This comparative example provides a nickel-cobalt hydroxide slurry leaching apparatus and leaching method. The difference from Example 1 is that the stirring speed in both the primary and secondary stirring slurry processes is 220 r / min, while the remaining methods, steps, and apparatus are the same as in Example 1.

[0095] Comparative Example 3 This comparative example provides a nickel-cobalt hydroxide slurry leaching apparatus and leaching method. The difference from Example 1 is that the stirring speed in both the primary and secondary stirring slurry processes is 400 r / min, while the remaining methods, steps, and apparatus are the same as in Example 1.

[0096] Comparative Example 4 This comparative example provides a nickel-cobalt hydroxide slurry leaching apparatus and leaching method. The difference from Example 1 is that the stirring speed of the first-stage stirring slurry is 400 r / min, and the stirring speed of the second-stage stirring slurry is 220 r / min. The remaining methods, steps and apparatus are the same as in Example 1.

[0097] The particle size distribution and viscosity stability of the homogenized slurry prepared in Examples 1-8 and Comparative Examples 1-4 were tested in this invention, and the results are shown in Table 1.

[0098] Table 1 As can be seen from Table 1, the homogenized slurries prepared in Examples 1-3 have a concentrated particle size distribution, good uniformity, and their viscosity changes little over time, indicating high stability.

[0099] Compared to Example 1, the particle size distribution concentration of Example 4 is reduced. This is mainly because the flow rate of nickel-cobalt hydroxide material is too high, resulting in some materials failing to fully contact the mixture, leading to large particles remaining in the slurry. Meanwhile, the viscosity stability of Example 5 is poor. This is mainly because the flow rate of nickel-cobalt hydroxide material is too low, resulting in a decrease in slurry concentration. After standing for a period of time, the slurry separates severely, resulting in poor viscosity stability and insufficient uniformity.

[0100] In Example 6, the mixing and slurrying time was too short, which failed to fully mix the nickel-cobalt hydroxide material and the washing liquid, resulting in a poor particle size distribution concentration and thus reducing the uniformity of the slurry.

[0101] Compared to Example 1, the particle size distribution concentration in Example 7 is slightly worse. This is because the proportion of recycled leachate is too small, resulting in a lower concentration of H in the leachate.+ A decrease in molar concentration reduces the solubility of minerals; the decreased viscosity stability in Example 8 is due to the excessive proportion of recycled leachate, leading to increased H... + The increased concentration of nickel-cobalt salts in the leachate leads to higher viscosity and poorer stability.

[0102] As shown in Table 1, the liquid-to-solid ratio of nickel-cobalt hydroxide material to the mixture in Comparative Example 1 exceeded the limit, and the moisture content was too high, resulting in the viscosity stability of the homogenized slurry being lower than that in Example 1.

[0103] Compared to Example 1, the particle size distribution concentration in Comparative Examples 2-4 deteriorated. In Comparative Example 2, both stages of stirring and slurrying operated at low speeds, resulting in poor material dispersion and a higher amount of residual particulate material. In Comparative Example 3, both stages of stirring and slurrying operated at high speeds, which improved the dispersion effect but significantly increased energy consumption, thus reducing production efficiency. In Comparative Example 4, the speed of the first-stage stirring and slurrying was too fast, causing unslurried material in the slurry tank to flow directly into the inner tank. At the same time, the speed of the second-stage stirring and slurrying was too slow, failing to effectively disperse the material, leading to an increase in particulate impurities and reducing the uniformity of the slurry.

[0104] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A method for slurry leaching of nickel-cobalt hydroxide, characterized in that, The nickel-cobalt hydroxide slurry leaching method includes: Nickel-cobalt hydroxide material and the mixed liquid are separately transported to a pulping tank for pulping treatment to obtain homogenized slurry; The homogenized slurry is then leached to obtain a leachate, and a portion of the leachate is recycled back to the pulping process. The pulping process includes a first-stage agitated pulping and a second-stage agitated pulping performed sequentially, wherein the speed of the first-stage agitated pulping is less than the speed of the second-stage agitated pulping; The liquid-to-solid ratio in the pulping tank is (1~1.5):

1.

2. The nickel-cobalt hydroxide slurry leaching method according to claim 1, characterized in that, The conveying flow rate of the nickel-cobalt hydroxide material is 20t / h to 25t / h.

3. The nickel-cobalt hydroxide slurry leaching method according to claim 1 or 2, characterized in that, The pulping process takes 8 to 10 minutes. The homogenized slurry has a slurry concentration of 20% to 25%; The viscosity of the homogenized slurry is 14cp~35cp.

4. The nickel-cobalt hydroxide slurry leaching method according to claim 1, characterized in that, Part of the leachate is recycled to the primary stirred pulping process; In the mixture, the proportion of the leachate that is returned to the primary stirred pulping process is 50% to 55%.

5. The nickel-cobalt hydroxide slurry leaching method according to claim 1 or 4, characterized in that, The speed of the primary stirring and slurrying is 200 r / min to 250 r / min; The speed of the secondary stirring and slurrying is 350 r / min to 450 r / min.

6. A nickel-cobalt hydroxide slurry leaching apparatus for the nickel-cobalt hydroxide slurry leaching method according to any one of claims 1-5, characterized in that, The nickel-cobalt hydroxide slurry leaching apparatus includes a feeding assembly, a slurry tank, a slurry storage tank, and a leaching tank connected sequentially along the material direction, and the leaching tank is also connected to the slurry tank; The pulping tank is equipped with a homogenizing and stirring assembly and a disperser. The homogenizing and stirring assembly is located on the central axis of the slurry tank and is used for primary stirring and slurrying of the material. The disperser includes an inner tank, which is disposed on the inner wall of the pulping tank. After primary stirring and pulping, the material flows upward into the inner tank. The inner tank is equipped with a dispersion and stirring assembly for secondary stirring and slurrying of materials; The inner tank is also provided with an overflow port, which is connected to the slurry storage tank.

7. The nickel-cobalt hydroxide slurry leaching apparatus according to claim 6, characterized in that, The feeding assembly includes a shaftless screw conveyor, and the inlet end of the shaftless screw conveyor is also equipped with a metering component for weighing the material.

8. The nickel-cobalt hydroxide slurry leaching apparatus according to claim 7, characterized in that, A first flow meter is installed on the connecting pipe between the leaching tank and the pulping tank; The pulping tank is provided with a washing liquid inlet, and a second flow meter is installed at the washing liquid inlet; The first flow meter and the second flow meter are independently electrically connected to the metering component.

9. The nickel-cobalt hydroxide slurry leaching apparatus according to any one of claims 6-8, characterized in that, The homogenizing and stirring assembly includes a first driving component, a first rotating shaft, and stirring blades; The first driving member is located at the top of the pulping tank and is connected to the first rotating shaft. The first rotating shaft extends into the inner cavity of the pulping tank, and the stirring blade is provided at the end of the first rotating shaft away from the first driving member. The stirring blade includes two guide blades arranged in a cross configuration; The dispersion and stirring assembly includes a second driving component, a second rotating shaft, and at least one dispersion disk; The second driving member is located at the top of the inner tank and is connected to the second rotating shaft. The second rotating shaft extends into the inner cavity of the inner tank, and the dispersing disk is provided at the end of the second rotating shaft away from the second driving member. The dispersion disk includes a dispersion body, on which a plurality of upper guide protrusions and a plurality of lower guide protrusions are provided. The protrusion directions of the upper guide protrusions and the lower guide protrusions are opposite, and the upper guide protrusions and the lower guide protrusions are alternately arranged along the circumference of the dispersion body.

10. The nickel-cobalt hydroxide slurry leaching apparatus according to any one of claims 6-8, characterized in that, The volume ratio of the pulping tank to the inner tank is (25~40):1.

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