A production process of high-quality electroplating grade nickel sulfate large particle crystal

Abstract

The application discloses a production process of high-quality electroplating-grade nickel sulfate large-particle crystals, and relates to the technical field of preparation of nickel sulfate.The process measures, such as precisely controlling the concentration degree of nickel sulfate solution and the crystallization temperature, improving the saturation of the solution, adjusting the crystal structure transformation and the like, are adopted to promote the growth of large particles to form the large-particle crystals.The nickel sulfate crystals can meet the electroplating industry standards.The concentrated nickel sulfate solution is conveyed to a crystallizer through a pipeline, and the crystallizer is cooled by circulating cooling water, so that small crystals are formed by preliminary crystallization, and the small crystals are used as crystal seeds to grow into large particles in the crystallizer.The organic solvent with weak polarity is selected as a crystallizing agent to differentiate the crystal water in the nickel sulfate molecules, promote the generation and precipitation of the crystals, and improve the crystallization rate.The nickel-cobalt hydroxide raw material is subjected to ozone oxidation treatment and pH adjustment, so that the impurities in the nickel solution are separated and graded, and the subsequent wastewater treatment process is simplified.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of preparation of nickel sulfate, in particular to a production process of high-quality electroplating-grade nickel sulfate large-particle crystals. BACKGROUND

[0002] The electroplating-grade nickel sulfate is an indispensable key raw material in the fields of electronic electroplating and chemical nickel plating, and the crystal physical performance and chemical purity of the electroplating-grade nickel sulfate directly affect the smoothness, uniformity and corrosion resistance of the plating layer. With the surging demand for precise electronic components and high-grade decorative plating layers, the market is increasingly demanding large-particle, high-fluidity and low-impurity-content nickel sulfate crystals.

[0003] The traditional evaporation crystallization process controls the crystal nucleus growth through time delay and cooling rate, and is prone to cause the explosive formation of crystal nuclei due to the rapid increase of supersaturation, so that a large number of fine crystals are generated. Such crystals have poor fluidity, are easy to absorb moisture and form agglomerates, need additional granulation treatment, and are difficult to meet the stringent requirements of high-end electroplating on particle size uniformity. When nickel-cobalt hydroxide and other secondary resources are used as raw materials, metal impurities such as Fe 3+ , Cu 2+ , Zn 2+ in the leaching solution are difficult to separate efficiently. The existing process mostly relies on multi-stage precipitation-filtration and p204 organic extraction, and the process is long and easy to introduce organic residues, thereby increasing the burden of subsequent wastewater treatment.

[0004] In order to improve the crystallization rate, high-temperature concentration or the addition of inorganic salts such as ammonium sulfate is often used, but this easily induces crystal type distortion or encapsulates impurities, resulting in the excessive Cl - , Na + , Ca 2+ ions in the product; and although the organic solvent assisted crystallization can improve the saturation degree, improper selection of the solvent will also cause the crystal to be entrained with organic phase or be lost by dissolution, thereby reducing the purity of the product.

[0005] The improvement direction of the existing technology is mostly focused on equipment optimization or single parameter adjustment, and the nucleation-growth kinetics of the crystal and the deep removal mechanism of the impurities cannot be systematically and cooperatively controlled, so that the product is difficult to meet the electroplating-grade standard in terms of particle size, purity, crystallization rate and other core indicators.

[0006] Therefore, it is urgent to develop a low-cost and highly controllable production process of nickel sulfate large-particle crystals, to realize the green preparation of high-quality electroplating-grade nickel sulfate through the integration of nucleation induction mechanism innovation and multi-stage impurity targeted removal technology. SUMMARY

[0007] The purpose of the present application is to provide a production process of high-quality electroplating-grade nickel sulfate large-particle crystals to solve the problems in the prior art.

[0008] To solve the above technical problems, the present application provides the following technical solutions: a high-quality electroplating-grade nickel sulfate large-particle crystal production process, comprising the following production steps:

[0009] (1) A slurry is prepared by mixing nickel-cobalt hydroxide raw material with water at a solid-liquid ratio of 1:2-10, concentrated sulfuric acid is added to the slurry, the pH value of the solution is adjusted to 1.0-1.5, and the solution is reacted at 60-90℃ for 0.5-3h;

[0010] (2) The temperature is kept at 60-70℃, the stirring is started, the rotating speed is controlled at 120-300rpm, an appropriate amount of nickel carbonate is added to the slurry to adjust the pH value to 3.5-4.0, the ozone is passed in for 30-120min, then the solid-liquid separation is carried out, the separated solution is added with nickel carbonate again to increase the pH value to 4.0-5.0, the ozone is passed in for another 30-45min, and the solid-liquid separation is carried out to further precipitate and separate the impurity elements such as cobalt, manganese, iron and aluminum in the nickel solution;

[0011] (3) The nickel solution obtained in step (2) is aged, filtered, and then extracted and separated by using a nickel extractant to obtain an organic phase loaded with nickel;

[0012] (4) The organic phase loaded with nickel is back-extracted with a sulfuric acid solution of a certain concentration to obtain back-extracted nickel sulfate solution;

[0013] (5) The back-extracted nickel sulfate solution is added to a concentration kettle, heated and warmed to 80-90℃, when the solution is concentrated to a nickel content of 300-400g / L, the evaporation is stopped, the solution is delivered to the bottom of a crystallization tank by a pipeline, a crystallization agent is added to a volume of 50%-60% of the volume of the solution, naturally cooled to 35-40℃, and then separated by centrifugation and dried to obtain high-quality electroplating-grade nickel sulfate large-particle crystals.

[0014] Further, the mass percentage of the chemical element composition of the nickel-cobalt hydroxide in step (1) includes: 2-15% of cobalt, 30-40% of nickel, 1-7% of iron, 2-6% of manganese, 0.1-3% of aluminum, 0.1-1% of silicon, 0.2-2% of calcium, and 0.5-5% of magnesium.

[0015] Further, the concentration of the ozone in step (2) is 20-100mg / L, and the flow rate of the ozone is 1-50m 3 / h.

[0016] Further, the nickel extractant in step (3) is HBL110 type.

[0017] Further, the volume ratio of the filtered solution to the nickel extractant HBL110 in step (3) is 1:6.5.

[0018] Further, the volume ratio of the organic phase (extractant) loaded with nickel in step (4) to the sulfuric acid solution is 8.5:1.

[0019] Further, the heating rate in step (5) is 0.5-2℃ / min.

[0020] Further, the outside of the pipeline is circulated with cooling water in step (5) to control the temperature when reaching the crystallization tank to be 53-57℃.

[0021] Further, the crystallization agent in step (5) is one of ethanol, isopropyl alcohol, and ethylene glycol.

[0022] Compared with the prior art, the present application has the following beneficial effects:

[0023] (1) The present application improves the saturation of the nickel sulfate solution by changing the reaction conditions and the crystal form of the solute, and promotes the formation of large particles. By precisely selecting and controlling the key parameters such as the crystallization temperature, concentration, and crystallization aid, the obtained nickel sulfate crystals meet the industry standards in terms of particle morphology and particle size distribution.

[0024] (2) After concentrating the nickel sulfate solution, the present application delivers the liquid to the crystallizer through a pipeline, and circulates cooling water outside the pipeline to cool the concentrated nickel sulfate solution and preliminarily realize crystallization to form small particle crystals, which are used as seeds to further grow in the crystallizer to form large particle crystals.

[0025] (3) The present application selects an organic solvent with weaker polarity than water as a crystallization agent, which can regulate water molecules when combined with Ni 2+ and SO4 2- , thereby weakening the solvation of water molecules to precipitate nickel sulfate crystals. Nickel sulfate is slightly soluble or insoluble in the crystallization agent, and by adding a high concentration of the crystallization agent, the further precipitation of the crystals is promoted, and the crystallization rate is improved.

[0026] (4) The present application uses nickel-cobalt hydroxide as raw material to prepare high-quality nickel sulfate crystals. By ozone oxidation treatment of the nickel-cobalt hydroxide leaching solution, impurity precipitation and separation are realized, and by pH adjustment, multiple impurities are stripped in stages, while reducing the introduction of other impurities and simplifying the subsequent wastewater treatment process. DETAILED DESCRIPTION

[0027] The technical solutions in the embodiments of the present application will be described below in conjunction with the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0028] Example 1

[0029] (1) A slurry was prepared by mixing nickel-cobalt hydroxide with water at a solid-to-liquid ratio of 1:5, and concentrated sulfuric acid was added to the slurry to adjust the pH of the solution to 1.5. The slurry was reacted at 75°C for 2 hours. The main component content of the sulfuric acid leaching solution is shown in Table 1. The mass percentage of the chemical elements in the nickel-cobalt hydroxide includes: cobalt 8%, nickel 35%, iron 4%, manganese 2.3%, aluminum 1.5%, silicon 0.5%, calcium 1%, and magnesium 2.5%;

[0030] Table 1 Main component content of sulfuric acid leaching solution

[0031]

[0032] (2) The temperature was maintained at 65°C, the stirring was started, the stirring speed was set to 300 rpm, and an appropriate amount of nickel carbonate was added to adjust the pH of the solution to 3.5. The ozone concentration was 80 mg / L, the ozone flow rate was 30 m 3 / h, and the ozone was continuously introduced for 60 min. The solution was separated by solid-liquid separation, and nickel carbonate was added to adjust the pH of the solution to 4.5. The ozone concentration was adjusted to 40 mg / L, the ozone flow rate was 15 m 3 / h, and the ozone was continuously introduced for 30 min. The solution was separated by solid-liquid separation to remove the impurity elements of cobalt, iron, manganese, and aluminum. The main component content of the ozone-purified solution is shown in Table 2.

[0033] Table 2 Main component content of ozone-purified solution

[0034]

[0035] (3) The nickel solution obtained in step (2) was placed in an aging tank and aged for 24 hours. The solution was filtered through a filter press / precision filter to obtain a precision-filtered nickel solution. The volume ratio of the solution to the nickel extractant HBL110 was 1:6.5, and the mixture was left to stand for 20 min to separate the phases to obtain a nickel-loaded organic phase.

[0036] (4) The nickel-loaded organic phase was back-extracted with a 2.25 mol / L sulfuric acid solution to obtain a back-extracted nickel sulfate solution. The main component content of the back-extracted solution is shown in Table 3. The volume ratio of the nickel-loaded organic phase to the sulfuric acid solution was 8.5:1, and the solution was left to stand for 35 min to separate the layers.

[0037] Table 3 Main component content of back-extracted solution

[0038]

[0039] (5) to the concentrated kettle, nickel back-extraction solution is added, heating is carried out at a heating rate of 0.5°C / min to 80°C, when the solution is concentrated to a nickel content of 300 g / L, evaporation is stopped, it is delivered to the bottom of the crystallization tank by a pipeline, the outside of the pipeline is circulated with cooling water to control the temperature to 55°C when it reaches the crystallization tank, ethanol is added to an ethanol volume of 55% of the solution volume, cooling is carried out at a rate of 0.3°C / min to 35°C, then centrifugal separation is carried out, drying is carried out at 55°C to a constant weight, high-quality electroplating-grade nickel sulfate large-particle crystals with an average particle size of 2.5-3.5 mm are obtained; the centrifuge rotation speed is 1200 rmp / min, the centrifugal separation time is 3 min.

[0040] Example 2

[0041] The back-extracted nickel sulfate solution obtained in Example 1 is added to a concentrated evaporation kettle, heating is carried out at a heating rate of 1.5°C / min to 85°C, when the solution is concentrated to a nickel content of 300 g / L, evaporation is stopped, it is delivered to the bottom of the crystallization tank by a pipeline, the outside of the pipeline is circulated with cooling water to control the temperature to 55°C when it reaches the crystallization tank, isopropanol is added to an isopropanol volume of 55% of the solution volume, cooling is carried out at a rate of 0.3°C / min to 40°C, then centrifugal separation is carried out, drying is carried out at 55°C to a constant weight, high-quality electroplating-grade nickel sulfate large-particle crystals with an average particle size of 2.5-3.5 mm are obtained; the centrifuge rotation speed is 1200 rmp / min, the centrifugal separation time is 3 min.

[0042] Example 3

[0043] The back-extracted nickel sulfate solution obtained in Example 1 is added to a concentrated evaporation kettle, heating is carried out at a heating rate of 2°C / min to 90°C, when the solution is concentrated to a nickel content of 300 g / L, evaporation is stopped, it is delivered to the bottom of the crystallization tank by a pipeline, the outside of the pipeline is circulated with cooling water to control the temperature to 55°C when it reaches the crystallization tank, ethylene glycol is added to an ethylene glycol volume of 55% of the solution volume, cooling is carried out at a rate of 0.3°C / min to 40°C, then centrifugal separation is carried out, drying is carried out at 60°C to a constant weight, high-quality electroplating-grade nickel sulfate large-particle crystals with an average particle size of 2.5-3.5 mm are obtained; the centrifuge rotation speed is 1200 rmp / min, the centrifugal separation time is 3 min.

[0044] Comparative Example 1

[0045] The back-extracted nickel sulfate solution obtained in Example 1 was added into a concentration evaporator, heated to 90℃ at a heating rate of 2℃ / min, when the solution was concentrated to a nickel content of 300g / L, the evaporation was stopped, directly poured into a crystallization tank, cooled to 55℃ at a cooling rate of 2℃ / min, 55% of ethylene glycol was added based on the volume of the solution, cooled to 40℃ at a cooling rate of 0.3℃ / min, then centrifuged, dried at 60℃ to constant weight, to obtain small particle crystals of electroplating grade nickel sulfate; the centrifuge speed was 1200rmp / min, and the centrifugation time was 3min.

[0046] Comparative Example 2

[0047] The back-extracted nickel sulfate solution obtained in Example 1 was added into a concentration evaporator, heated to 90℃ at a heating rate of 2℃ / min, when the solution was concentrated to a nickel content of 300g / L, the evaporation was stopped, directly poured into a crystallization tank, cooled to 55℃ at a cooling rate of 2℃ / min, 55% of ethylene glycol was added based on the volume of the solution, cooled to 40℃ at a cooling rate of 0.3℃ / min, then centrifuged, dried at 60℃ to constant weight, to obtain small particle crystals of electroplating grade nickel sulfate; the centrifuge speed was 1200rmp / min, and the centrifugation time was 3min.

[0048] Comparative Example 3

[0049] (1) The sulfuric acid leaching solution of Example 1 was taken, the temperature was kept at 65℃, the stirring was started, the speed was set to 300rpm, an appropriate amount of nickel carbonate was added to adjust the pH value of the solution to 3.5, ozone was continuously introduced, the concentration of ozone was 80mg / L, the flow rate of ozone was 30m 3 / h, the ozone introduction time was 90min, after the reaction was completed, solid-liquid separation was carried out, and the main component content of the ozone-purified solution is shown in Table 4;

[0050] Table 4 Main component content of ozone-purified solution

[0051]

[0052] (2) The filtrate obtained in step (1) and nickel extractant HBL110 were mixed at a volume ratio of 1:6.5, and then static phase separation was carried out for 20min to obtain a nickel-loaded organic phase;

[0053] (3) The nickel-loaded organic phase was back-extracted with a 2.25mol / L sulfuric acid solution to obtain a back-extracted nickel sulfate solution, and the main component content of the back-extracted solution is shown in Table 5; the volume ratio of the nickel-loaded organic phase to the sulfuric acid solution was 8.5:1, and the static layer separation time was 35min;

[0054] Table 5 Main component content of back-extracted nickel solution

[0055]

[0056] (4) to the concentrated evaporation kettle, add stripping nickel solution, heating at a rate of 0.5 °C / min to 80 °C, when the solution is concentrated to the nickel content of 300 g / L, stop evaporation, pipe to the bottom of the crystallization tank, the outside of the pipe circulating cooling water to control the temperature to 55 °C when reaching the crystallization tank, add ethanol to the ethanol volume is 55% of the solution volume, cooling to 35 °C at a rate of 0.3 °C / min, then centrifugal separation, drying at 55 °C to constant weight, to get the average particle size of 2.5-3.5 mm of crude nickel sulfate large particle crystals; the centrifuge speed is 1200 rmp / min, centrifugal separation time 3 min.

[0057] Comparative Example 4

[0058] (1) take the sulfuric acid leaching solution of example 1, keep the temperature at 65 °C, open the stirring, set the speed to 300 rpm, add appropriate amount of nickel carbonate to adjust the pH value of the solution to 4.5, the concentration of ozone is 40 mg / L, the flow rate of ozone is 15 m 3 / h, continue to pass ozone for 90 min, solid-liquid separation, the main component content of the ozone purified solution is shown in table 6;

[0059] Table 6 main component content of ozone purified solution

[0060]

[0061] (2) the nickel solution obtained in step (1) is placed in the aging tank and aged for 24 h, and then filtered through a pressure filter / precision filter to obtain a precision filtered nickel solution, the volume ratio of the solution to the nickel extractant HBL110 is 1:6.5, and the static phase separation time after mixing is 20 min to obtain an organic phase loaded with nickel;

[0062] (3) the organic phase loaded with nickel is stripped with 2.25 mol / L sulfuric acid solution to obtain a stripped nickel sulfate solution, the main component content of the stripping solution is shown in table 3; the volume ratio of the organic phase loaded with nickel to the sulfuric acid solution is 8.5:1, and the static layering time is 35 min;

[0063] Table 7 main component content of stripping nickel solution

[0064] Test item Ni Co Fe Al Mn Ca Mg Concentration (g / L) 110.85 0.67 ＜0.001 ＜0.001 0.34 ＜0.01 0.38

[0065] (4) to the concentrated evaporation kettle, stripping nickel liquid is added, heating is carried out at a heating rate of 0.5℃ / min to 80℃, when the solution is concentrated to a nickel content of 300g / L, evaporation is stopped, and the solution is delivered to the bottom of the crystallization tank by a pipeline, the outside of the pipeline is circulated with cooling water to control the temperature of the solution when it reaches the crystallization tank to be 55℃, ethanol is added to a volume of 55% of the solution, cooling is carried out at a rate of 0.3℃ / min to 35℃, then centrifugal separation is carried out, and drying is carried out at 55℃ to a constant weight, to obtain crude nickel sulfate large particle crystals with an average particle size of 2.5-3.0mm; the centrifuge rotates at a speed of 1200rmp / min, and the centrifugal separation time is 3min.

[0066] It will be obvious to a person skilled in the art that the application is not limited to the details of the foregoing exemplary embodiments and can be implemented in other concrete forms without departing from the spirit or essential characteristics of the application. Therefore, the embodiments should be considered in all respects as illustrative and not restrictive, and the scope of the application is defined by the appended claims rather than the foregoing description, and it is intended to embrace all changes falling within the meaning and scope of the equivalent elements of the claims. Any mark in the claims should not be considered as limiting the involved claim.

Claims

1. A process for the production of high quality electroplating grade nickel sulfate large granular crystals, characterized by, The method comprises the following production steps: (1) a slurry is prepared by mixing nickel-cobalt hydroxide raw material with water at a solid-liquid ratio of 1:2-10, concentrated sulfuric acid is added to the slurry, the pH value of the solution is adjusted to 1.0-1.5, and the solution is reacted at 60-90℃ for 0.5-3h; (2) the temperature is kept at 60-70℃, stirring is started, the rotating speed is controlled at 120-300rpm, an appropriate amount of nickel carbonate is added to the slurry to adjust the pH value to 3.5-4.0, the ozone is passed in for 30-120min, then the solid-liquid separation is performed, and the separated solution is added with nickel carbonate again to increase the pH value of the slurry to 4.0-5.0, the ozone is passed in for 30-45min, and the solid-liquid separation is performed to complete the precipitation separation of impurity elements in the acid leaching nickel solution, the impurity elements including cobalt, manganese, iron and aluminum; (3) the filtrate obtained in step (2) is aged, filtered, and separated by using a nickel extractant to obtain an organic phase loaded with nickel; (4) the organic phase loaded with nickel is back-extracted with a sulfuric acid solution of a certain concentration to obtain back-extracted nickel sulfate solution; (5) the back-extracted nickel sulfate solution is added to a concentration kettle, heated to 80-90℃, when the solution is concentrated to a nickel content of 300-400g / L, the evaporation is stopped, the solution is delivered to the bottom of a crystallization tank through a pipeline, a crystallization agent is added to a volume of the crystallization agent being 50%-60% of the volume of the solution, the temperature is naturally reduced to 35-40℃, and then the high-quality electroplating-grade nickel sulfate large-particle crystals are obtained by centrifugal separation and drying.

2. A process for producing high quality electroplating grade nickel sulfate large granular crystals as claimed in claim 1, wherein, The mass percentage of the chemical elements in the nickel-cobalt hydroxide in step (1) comprises: 2-15% of cobalt, 30-40% of nickel, 1-7% of iron, 2-6% of manganese, 0.1-3% of aluminum, 0.1-1% of silicon, 0.2-2% of calcium, and 0.5-5% of magnesium.

3. A process for producing high quality electroplating grade nickel sulfate large size crystals as claimed in claim 1 wherein, The concentration of the ozone in the step (2) is 20-100 mg / L, and the flow rate of the ozone is 1-50 m 3 / h.

4. A process for producing high quality electroplating grade nickel sulfate large size crystals as claimed in claim 1 wherein, The nickel extractant in step (3) is HBL110.

5. A process for producing high quality electroplating grade nickel sulfate large size crystals as claimed in claim 1 wherein, The volume ratio of the filtrate to the nickel extractant HBL110 in step (3) is 1:6.

5.

6. A process for producing high quality electroplating grade nickel sulfate large size crystals as claimed in claim 1 wherein, The volume ratio of the organic phase loaded with nickel to the sulfuric acid solution in step (4) is 8.5:

1.

7. A process for producing high quality electroplating grade nickel sulfate large size crystals as claimed in claim 1 wherein, The heating rate in step (5) is 0.5-2℃ / min.

8. A process for producing high quality electroplating grade nickel sulfate large size crystals as claimed in claim 1 wherein, The outside of the pipeline is circulated with cooling water to control the temperature of the solution reaching the crystallization tank to be 53-57℃.

9. A process for producing high quality electroplating grade nickel sulphate large size crystals as claimed in claim 1 wherein, The crystallization agent in step (5) is one of ethanol, isopropyl alcohol and ethylene glycol. ​

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