Preparation method of high-cobalt spherical nickel hydroxide

Abstract

The invention relates to a preparation method of high-cobalt spherical nickel hydroxide, which is characterized in that nickel sulfate, ionic membrane alkali and liquid ammonia are used as raw materials, pure water is adopted to prepare a solution, a sodium hydroxide solution, ammonia water and water in a certain proportion are added into a reaction kettle to serve as a base solution during reaction, stirring is started, the temperature is kept at 50-60 DEG C, and stirring is performed for 2-3 hours; and continuously adding a nickel sulfate solution, a sodium hydroxide solution and ammonia water into the reaction kettle according to a certain proportion for reaction to prepare high-cobalt spherical nickel hydroxide, and washing, centrifuging and drying the prepared high-cobalt spherical nickel hydroxide to obtain the high-cobalt spherical nickel hydroxide product. The high-cobalt spherical nickel hydroxide prepared by the method is spherical in microstructure, and has the advantages of high purity, good fluidity, controllable granularity, easiness in continuous production and the like.

Description

Technical Field

[0001] The invention belongs to the technical field of nickel hydroxide production, and particularly relates to a method for preparing high-cobalt spherical nickel hydroxide. Background Art

[0002] Nickel hydroxide is the positive active material of nickel-based batteries (Ni / MH, Ni / Cd, Ni / Zn, etc.), and its performance directly affects the performance of the battery. The preparation and research of high-performance spherical nickel hydroxide is the focus of attention of domestic and foreign peers. At present, the methods for producing nickel hydroxide at home and abroad include: liquid phase precipitation method, homogeneous precipitation method, hydrothermal method, oxidation method, high-pressure hydrolysis method, ion exchange resin method, microemulsion method, electrolysis method, mechanochemical synthesis method, etc. The crystal forms of nickel hydroxide materials are α-type, β-type and γ-type, and the morphology is irregular, spherical, lamellar, tubular, hollow spherical, etc. γ-Ni(OH)2 is an overcharge product of the battery, which will cause the electrode to expand; α-Ni(OH)2 is unstable in an alkaline environment. The tap density of spherical nickel hydroxide is large, which is conducive to improving the electrode capacity. Therefore, alkaline nickel-based batteries usually use β-Ni(OH)2, which can work stably and discharge at high power in an alkaline environment. Patent CN103204554A adds nickel salt, anionic active agent and cationic active agent into the solution, dissolves and mixes with alkaline reagent in autoclave, reacts at 80-100°C for 1-10h, filters and washes to obtain nickel hydroxide. This method has a high reaction temperature and a long reaction time, and requires the introduction of additives. Patent CN104319394A uses 100-140g / L NiSO4 solution, 6-8mol / L NaOH solution and liquid ammonia with a specific gravity of 0.9-0.95 as raw materials, adds these three into the reactor in a certain proportion, reacts for 6-12h, washes and dries to obtain nickel hydroxide. The disadvantage of this method is that the reaction time is long and the introduction of ammonia water needs to be controlled separately. Patent CN1467160A injects three solutions, including a mixed solution of inorganic salts containing metal elements and nickel salts, a coordination mixture solution and an alkaline solution, into a reactor filled with oil base liquid in parallel, and controls the Ni 2+ The concentration, pH value and stirring speed of the reaction product are treated with hot alkali to obtain spherical nickel hydroxide. The disadvantage of this method is that the pH needs to be controlled and the reaction time is 10h~12h; Patent CN102664266A proposes a method for preparing spherical nickel hydroxide by doping zinc, manganese and aluminum, and a mixed aqueous solution of nickel sulfate salt, zinc sulfate salt, manganese sulfate salt and aluminum sulfate salt, ammonia water, and sodium hydroxide aqueous solution are continuously injected into the reactor through a precision flow control system, and the temperature, pH value and stirring intensity of the reaction system are controlled. The reaction generates spherical nickel hydroxide, which then flows out continuously through the overflow port of the reactor, and is aged, washed and dried. The disadvantage of this method is that the pH needs to be controlled, and the nickel hydroxide slurry needs to be aged, which prolongs the time for preparing nickel hydroxide. Summary of the invention

[0003] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a production method for high-cobalt nickel hydroxide with a spherical micromorphology. The method has a short process flow, low energy consumption, and a friendly production environment. The product produced has high purity, good fluidity, and controllable particle size.

[0004] The present invention adopts the following technical solution: 1) Raw material solution configuration: prepare nickel sulfate solution with nickel concentration of 120-140g / L, cobalt concentration of 8-12g / L and zinc concentration of 6-8g / L, sodium hydroxide solution with concentration of 6-8mol / L and ammonia water with specific gravity of 0.9-1.0 for standby use; (the zinc content can increase the cycle life of the battery, the concentration of the solution in the product is 6-8g / L, which can meet 2.5-3.5% in the product) 2) Synthesis: Add pure water, sodium hydroxide solution and ammonia water into the reactor, and prepare them according to the volume ratio of pure water: sodium hydroxide solution: ammonia water = 1: (0.01-0.03): (0.1-0.3); after the preparation is qualified, start stirring and heat up to 50-60°C; start the metering pump and continuously inject nickel sulfate solution, sodium hydroxide solution and ammonia water into the reactor for synthesis reaction, and the flow ratio is nickel sulfate solution: sodium hydroxide solution: ammonia water = 1: (0.4-0.6): (0.1-0.3); 3) The high-cobalt spherical nickel hydroxide material prepared in step 2) is put into a washing kettle and washed with deionized water until the pH of the washing water is 9; 4) Drying: The product obtained in step 3) is transferred to a centrifuge for solid-liquid separation, and the obtained solid product is dried at 90-110° C. for 10-15 hours to obtain the high-cobalt spherical nickel hydroxide product of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0005] Figure 1 This is the SEM image of the spherical nickel hydroxide product prepared in Example 1.

[0006] Figure 2 This is the SEM image of the spherical nickel hydroxide product prepared in Example 3. DETAILED DESCRIPTION

[0007] The present invention is further explained below with reference to specific embodiments.

[0008] Example 1: A method for producing high-cobalt spherical nickel hydroxide, the specific steps of which are as follows: (1) Preparation of raw material solution: prepare nickel sulfate solution with nickel concentration of 120g / L, cobalt concentration of 12g / L, and zinc concentration of 6g / L. Prepare sodium hydroxide solution with a concentration of 6mol / L and ammonia water with a specific gravity of 0.9 for later use; (2) Synthesis: pure water, sodium hydroxide solution and ammonia water are added to the reaction kettle, and the volume ratio is pure water: sodium hydroxide solution: ammonia water = 1: 0.01: 0.1; after the preparation is qualified, stirring is started and the temperature is raised to 50°C; the metering pump is turned on to continuously inject nickel sulfate solution, sodium hydroxide solution and ammonia water into the reaction kettle for synthesis reaction, and the flow ratio is nickel sulfate solution: sodium hydroxide solution: ammonia water = 1: 0.4: 0.1; (3) Washing: The high-cobalt spherical nickel hydroxide material prepared in step (2) is placed in a washing kettle and washed with deionized water until the pH of the washing water reaches 9; (4) Drying: The product obtained in step (3) is transferred to a centrifuge for solid-liquid separation, and the obtained solid product is dried at 90° C. for 15 hours to obtain the high-cobalt spherical nickel hydroxide product of the present invention.

[0009] The obtained high-cobalt spherical nickel hydroxide is a light green powder with a bulk density of 1.70 g / cm 3 The microstructure is spherical and the median diameter is 10.0μm.

[0010] Example 2: A method for producing high-cobalt spherical nickel hydroxide, the specific steps of which are as follows: (1) Preparation of raw material solution: prepare nickel sulfate solution with nickel concentration of 130g / L, cobalt concentration of 10g / L, and zinc concentration of 6g / L. Prepare sodium hydroxide solution with a concentration of 7mol / L and ammonia water with a specific gravity of 0.92 for later use; (2) Synthesis: pure water, sodium hydroxide solution and ammonia water are added to the reaction kettle, and the volume ratio is pure water: sodium hydroxide solution: ammonia water = 1: 0.02: 0.2; after the preparation is qualified, stirring is started and the temperature is raised to 55°C; the metering pump is turned on to continuously inject nickel sulfate solution, sodium hydroxide solution and ammonia water into the reaction kettle for synthesis reaction, and the flow ratio is nickel sulfate solution: sodium hydroxide solution: ammonia water = 1: 0.5: 0.15; (3) Washing: The high-cobalt spherical nickel hydroxide material prepared in step (2) is placed in a washing kettle and washed with deionized water until the pH of the washing water reaches 9; (4) Drying: The product obtained in step (3) is transferred to a centrifuge for solid-liquid separation, and the obtained solid product is dried at 100° C. for 12 hours to obtain the high-cobalt spherical nickel hydroxide product of the present invention.

[0011] The obtained high-cobalt spherical nickel hydroxide is a light green powder with a bulk density of 1.71 g / cm 3 The microscopic morphology is spherical and the median diameter is 10.3μm.

[0012] Example 3: A method for producing high-cobalt spherical nickel hydroxide, the specific steps of which are as follows: (1) Preparation of raw material solution: prepare nickel sulfate solution with nickel concentration of 140g / L, cobalt concentration of 8g / L, and zinc concentration of 6g / L. Prepare 8mol / L sodium hydroxide solution and ammonia water with a specific gravity of 0.95 for later use; (2) Synthesis: pure water, sodium hydroxide solution and ammonia water are added to the reaction kettle, and the volume ratio is pure water: sodium hydroxide solution: ammonia water = 1: 0.017: 0.18; after the preparation is qualified, stirring is started and the temperature is raised to 60°C; the metering pump is turned on to continuously inject nickel sulfate solution, sodium hydroxide solution and ammonia water into the reaction kettle for synthesis reaction, and the flow ratio is nickel sulfate solution: sodium hydroxide solution: ammonia water = 1: 0.55: 0.18; (3) Washing: The high-cobalt spherical nickel hydroxide material prepared in step (2) is placed in a washing kettle and washed with deionized water until the pH of the washing water reaches 9; (4) Drying: The product obtained in step (3) is transferred to a centrifuge for solid-liquid separation, and the obtained solid product is dried at 110° C. for 10 hours to obtain the high-cobalt spherical nickel hydroxide product of the present invention.

[0013] The obtained high-cobalt spherical nickel hydroxide is a light green powder with a bulk density of 1.74 g / cm 3 The microscopic morphology is spherical and the median diameter is 10.9μm.

[0014] The composition and content determination data of the high-cobalt spherical nickel hydroxide products prepared in the above Examples 1-3 are shown in Table 1.

[0015] Table 1 Determination data of composition and content of high-cobalt spherical nickel hydroxide products prepared in Examples 1-3 .

Claims

1. A method for preparing high-cobalt spherical nickel hydroxide, characterized in that: The following steps are involved: 1) Raw material solution preparation: prepare nickel sulfate solution with nickel concentration of 120-140g / L, cobalt concentration of 8-12g / L and zinc concentration of 6-8g / L, sodium hydroxide solution with concentration of 6-8mol / L and ammonia water with specific gravity of 0.9-1.0 for standby use; 2) Synthesis: Add pure water, sodium hydroxide solution and ammonia water into the reactor, and prepare them according to the volume ratio of pure water: sodium hydroxide solution: ammonia water = 1: (0.01-0.03): (0.1-0.3); after the preparation is qualified, start stirring and heat up to 50-60°C; start the metering pump and continuously inject nickel sulfate solution, sodium hydroxide solution and ammonia water into the reactor for synthesis reaction, and the flow ratio is nickel sulfate solution: sodium hydroxide solution: ammonia water = 1: (0.4-0.6): (0.1-0.3); 3) The high-cobalt spherical nickel hydroxide material prepared in step 2) is put into a washing kettle and washed with deionized water until the pH of the washing water is 9; 4) Drying: The product obtained in step 3) is transferred to a centrifuge for solid-liquid separation, and the obtained solid product is dried at 90-110° C. for 10-15 hours to obtain the high-cobalt spherical nickel hydroxide product.

2. The method for preparing a high-cobalt spherical nickel hydroxide according to claim 1, characterized in that: The composition and content of the high-cobalt spherical nickel hydroxide product prepared in step 4) are nickel: 52-53%, cobalt: 4.5%-5.5%, and zinc: 2.5-3.5%.

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