Method for precipitating nickel and cobalt in nickel-cobalt-containing solution and nickel-cobalt hydroxide product

Abstract

The present invention provides a method for precipitating nickel and cobalt in a nickel-cobalt-containing solution and a nickel-cobalt hydroxide product. The method comprises: step S100, using a first nickel-cobalt precipitation underflow to perform a seed pretreatment reaction on the nickel-cobalt-containing solution to form a pretreated nickel-cobalt ore pulp; step S200, adding an alkaline precipitation inducing agent to the second nickel-cobalt precipitation underflow or the first nickel-cobalt precipitation overflow to perform an alkali conversion reaction to form an alkali conversion crystal slurry; step S300, continuously passing the pretreated nickel-cobalt ore pulp and the alkali conversion crystal slurry into a reactor to perform a nickel-cobalt precipitation reaction to obtain a nickel-cobalt precipitated ore pulp; step S400, continuously performing a dense separation treatment on the nickel-cobalt precipitated ore pulp; step S500, filtering and washing the third nickel-cobalt precipitation underflow in sequence to obtain a nickel-cobalt hydroxide product, which solves the problems of small MHP particle size and difficulty in sedimentation, high filter cake moisture content, or poor precipitation rate, and high magnesium content before technical improvement when precipitating nickel and cobalt from a nickel-cobalt-containing solution in the prior art.

Description

Technical Field

[0001] The invention relates to the technical field of laterite nickel ore hydrometallurgy, and in particular to a method for precipitating nickel and cobalt in a nickel-cobalt-containing solution and a nickel-cobalt hydroxide product. Background Art

[0002] Nickel-cobalt-containing solutions, such as laterite nickel ore acid leaching iron-aluminum removal solution, are obtained through the hydrometallurgy of laterite nickel ore. The main processes include atmospheric pressure leaching and high-pressure leaching, usually sulfuric acid leaching. The high-pressure acid leaching process is used to treat limonite-type laterite nickel ore. It has the advantages of short leaching time, low iron leaching rate, high nickel-cobalt leaching rate and recovery rate, and low production cost. In recent years, it has become the preferred process for most new laterite nickel ore hydrometallurgy projects. The high-pressure leaching process of laterite nickel ore mainly includes high-pressure acid leaching, slurry neutralization, countercurrent washing, neutralization and impurity removal, nickel-cobalt precipitation and other processes. The nickel-cobalt precipitation process is the solution of the laterite nickel ore high-pressure acid leaching solution after neutralization and impurity removal, also known as the laterite nickel ore acid leaching iron-aluminum removal solution.

[0003] The nickel-cobalt precipitation process in the prior art mostly adopts the method of sodium hydroxide or sulfide precipitation, such as:

[0004] Patent CN101575676A proposes a method for precipitation iron removal and nickel-cobalt enrichment, in which the nickel-cobalt enrichment process uses a sulfiding agent for sulfidation precipitation. The patent uses a sulfiding agent, such as one or more of hydrogen sulfide, hydrogen persulfide, sodium hydrosulfide, sodium sulfide, potassium sulfide, ammonium sulfide, magnesium sulfide, and zinc sulfide, during nickel-cobalt precipitation enrichment. Hydrogen sulfide precipitation has the best effect, but hydrogen sulfide is highly toxic, has high requirements for operation and system, and the subsequent treatment of the intermediate product of sulfidation precipitation is difficult.

[0005] Patent CN102061387A discloses a two-stage nickel precipitation method, in which NaOH solution is added to a nickel sulfate solution containing magnesium, the pH is adjusted to 7.5-8.5, the reaction temperature is 20-80°C, the reaction time is 0.5-3 hours, and the obtained precipitate is separated from the mother liquor. The precipitate enters the next step, NaOH solution is added to the mother liquor, the pH is adjusted to 9-10, the reaction temperature is 20-80°C, the reaction time is 0.5-3 hours, and the final precipitate is separated from the mother liquor and returned to the stirring leaching system for circulation. This patent directly uses sodium hydroxide or mixed alkali solution to precipitate nickel and cobalt, and the product is small and difficult to precipitate, resulting in a high water content of the product.

[0006] Patent CN101921001A proposes a process for preparing cobalt hydroxide from a cobalt sulfate solution. First, magnesium hydroxide slurry is used to precipitate cobalt in a cobalt precipitation tank for the first time. After the cobalt precipitation slurry obtained by the reaction passes through a cobalt precipitation buffer tank, 30% to 50% of the slurry is returned to the cobalt precipitation tank for the first time. The remaining slurry is filtered, and the filter cake obtained by the filter pressing is sent to a drying process. The dried cobalt hydroxide is the product, and the filtrate is subjected to a second cobalt precipitation with magnesium hydroxide. This technology directly uses magnesium hydroxide as a precipitant, but its alkalinity is limited. Although it avoids the generation of local over-alkalinity, the activity of magnesium hydroxide is reduced after slurrying, resulting in the adverse effect of a low cobalt precipitation rate.

[0007] In summary, the process of nickel-cobalt precipitation by hydrogen sulfide is widely used, with the advantages of high precipitation rate, low precipitation pH, and the ability to recover nickel-cobalt without purification under acidic conditions of the leaching solution. However, hydrogen sulfide is highly toxic, which poses great safety and environmental risks, and the subsequent treatment process of the intermediate products obtained by precipitation is also extremely cumbersome. The process of nickel-cobalt precipitation by sodium hydroxide is simple, and the equipment investment is small. However, the direct use of strongly alkaline sodium hydroxide as a precipitate will result in a small particle size and poor sedimentation ability of the nickel-cobalt hydroxide (MHP) precipitation product, which is not conducive to the liquid-solid separation process, and the filter cake has a high water content, which causes difficulties for subsequent transportation and treatment. In addition, the direct use of magnesium hydroxide as a precipitant is prone to low precipitation rate due to its limited alkalinity and low activity.

[0008] In view of this, the present invention is proposed. Summary of the invention

[0009] The main purpose of the present invention is to provide a method for precipitating nickel and cobalt from a nickel-cobalt solution and a nickel-cobalt hydroxide product, so as to solve the problems in the prior art of precipitating nickel and cobalt from a nickel-cobalt solution, such as small MHP particle size and difficulty in sedimentation, high filter cake moisture content, or poor precipitation rate, and high magnesium content before technical improvement.

[0010] To achieve the above object, according to one aspect of the present invention, a method for precipitating nickel and cobalt in a nickel-cobalt-containing solution is provided, wherein the cations in the nickel-cobalt-containing solution include nickel ions, cobalt ions, magnesium ions and manganese ions, and the method comprises: step S100, using a first nickel-cobalt precipitation underflow to perform a seed pretreatment reaction on the nickel-cobalt-containing solution to form a pretreated nickel-cobalt ore slurry; step S200, adding an alkaline precipitation inducer to the second nickel-cobalt precipitation underflow to perform a alkali conversion reaction to form an alkali conversion slurry; or, adding an alkaline precipitation inducer to the first nickel-cobalt precipitation overflow to perform a alkali conversion reaction, Forming alkali-converting slurry; step S300, continuously introducing the pretreated nickel-cobalt slurry and the alkali-converting slurry into the reactor for nickel-cobalt precipitation reaction to obtain nickel-cobalt precipitated slurry; step S400, continuously performing dense separation treatment on the nickel-cobalt precipitated slurry to obtain nickel-cobalt precipitation underflow and nickel-cobalt precipitation overflow; the nickel-cobalt precipitation underflow is composed of a first nickel-cobalt precipitation underflow, a second nickel-cobalt precipitation underflow and a third nickel-cobalt precipitation underflow; the nickel-cobalt precipitation overflow includes the first nickel-cobalt precipitation overflow; step S500, filtering and washing the third nickel-cobalt precipitation underflow in sequence to obtain a nickel-cobalt hydroxide product.

[0011] Furthermore, in the above step S100, the temperature of the seed crystal pretreatment reaction is 25°C to 100°C, preferably 50°C to 80°C, and the time of the seed crystal pretreatment reaction is 0.1h to 10h, preferably 1h to 5h.

[0012] Furthermore, in the above step S100, the mass of the first nickel-cobalt precipitation underflow is 1% to 99% of the total mass of the nickel-cobalt precipitation underflow.

[0013] Furthermore, in the above step S200, the total mass concentration of the alkaline precipitation inducer is 0.1% to 60%, preferably 3% to 20%, and further preferably 3% to 15%.

[0014] Furthermore, in the above step S200, the alkaline precipitation inducing agent is a mixed solution formed by an alkaline substance and water, wherein the alkaline substance is selected from any one or more of sodium hydroxide, potassium hydroxide, calcium hydroxide, magnesium hydroxide, calcium oxide, magnesium oxide and carbonate.

[0015] Furthermore, in the above step S200, the alkaline substance is a mixture of sodium hydroxide and potassium hydroxide, and the mass ratio of sodium hydroxide to potassium hydroxide is (1-4):(1-4).

[0016] Furthermore, based on the theoretical total molar amount of hydroxide and carbonate required for nickel-cobalt precipitation in the nickel-cobalt slurry after the above pretreatment, the total molar amount of hydroxide and / or carbonate in the alkaline precipitation inducer is 0.5 to 1.5 times the theoretical total molar amount, preferably 0.8 to 0.9 times.

[0017] Furthermore, in the above step S200, the temperature of the alkali transfer reaction is 25-100°C, preferably 50-60°C, and the time of the alkali transfer reaction is 0.1-30 min, preferably 1 min-10 min, and further preferably 3 min-5 min.

[0018] Furthermore, in the above step S200, the mass of the first nickel-cobalt precipitation overflow is 1% to 99% of the total mass of the nickel-cobalt precipitation overflow, and preferably 5% to 30%.

[0019] Furthermore, in the above step S200, the mass of the second nickel-cobalt precipitation underflow is 1% to 99% of the total mass of the nickel-cobalt precipitation underflow.

[0020] Furthermore, when an alkaline precipitation inducer is added to the above-mentioned first nickel-cobalt precipitation overflow to carry out a alkali conversion reaction to form an alkali conversion slurry, the mass ratio of the first nickel-cobalt precipitation underflow, the second nickel-cobalt precipitation underflow and the third nickel-cobalt precipitation underflow is (55%~89%): (10%~40%): (1%~5%).

[0021] Furthermore, the temperature of the nickel-cobalt precipitation reaction is 50° C. to 70° C., the time of the nickel-cobalt precipitation reaction is 0.5 h to 5 h, and the nickel-cobalt precipitation rate in the nickel-cobalt precipitation reaction is 70% to 98%.

[0022] Furthermore, the cationic components in the above-mentioned nickel-cobalt solution are as follows: nickel ions 0.1g / L~120g / L, cobalt ions 0.1g / L~120g / L, magnesium ions 0.5g / L~25g / L, divalent manganese ions 0.5g / L~10g / L, and further, preferably nickel ions 3g / L~5g / L, cobalt ions 0.2g / L~0.5g / L, magnesium ions 5g / L~8g / L, and divalent manganese ions 2g / L~4g / L.

[0023] According to one aspect of the present invention, a nickel-cobalt hydroxide product is provided. The nickel-cobalt hydroxide product is prepared by the above-mentioned method of precipitating nickel-cobalt from a nickel-cobalt solution.

[0024] Furthermore, the D50 particle size of the above-mentioned nickel cobalt hydroxide product is 20μm~60μm, the moisture content is 45%~55%, the nickel content is 39%~44%, the manganese content is 2%~4%, and the magnesium content is 0.05%~1.0%.

[0025] By applying the technical solution of the present application, the present invention provides a method for precipitating nickel and cobalt in a nickel-cobalt solution and a nickel-cobalt hydroxide product. The present invention effectively solves the problems of poor environmental protection, small particle size of nickel-cobalt hydroxide, and difficulty in sedimentation, high moisture content of the filter cake, or poor sedimentation rate when nickel and cobalt are precipitated from a laterite nickel ore acid leaching iron-removing aluminum solution in the prior art. By adopting the above-mentioned nickel-cobalt precipitation method, the auxiliary agent used is more environmentally friendly, the sedimentation rate is high, and the nickel-cobalt hydroxide has a better morphology, a larger particle size, and good sedimentation ability, which is beneficial to the subsequent liquid-solid separation process, thereby also reducing the moisture content of the nickel-cobalt hydroxide product. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The drawings constituting a part of the present application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0027] Figure 1 A process flow chart of a method for precipitating nickel and cobalt from a nickel and cobalt-containing solution according to an embodiment of the present invention is shown;

[0028] Figure 2 A process flow chart of a method for precipitating nickel and cobalt from a nickel and cobalt-containing solution according to another embodiment of the present invention is shown. DETAILED DESCRIPTION

[0029] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0030] As described in the background technology section, in the prior art, when nickel and cobalt are precipitated from the acid leaching solution for removing iron and aluminum from laterite nickel ore, the environmental protection is poor, the particle size of nickel and cobalt hydroxide is small, the water content of the filter cake is high, or the precipitation rate is low. In order to solve the above problems, the present invention provides a method for precipitating nickel and cobalt in a nickel-cobalt-containing solution and a nickel and cobalt hydroxide product.

[0031] In a typical embodiment of the present application, a method for precipitating nickel and cobalt in a nickel-cobalt solution is provided, wherein the cations in the nickel-cobalt solution include nickel ions, cobalt ions, magnesium ions and manganese ions, wherein Figure 1 and Figure 2As shown, the method includes: step S100, using the first nickel-cobalt precipitation underflow to perform seed pretreatment reaction on the nickel-cobalt solution to form a pretreated nickel-cobalt slurry; step S200, adding an alkaline precipitation inducer to the second nickel-cobalt precipitation underflow to perform a alkali conversion reaction to form an alkali conversion crystal slurry; or, adding an alkaline precipitation inducer to the first nickel-cobalt precipitation overflow to perform a alkali conversion reaction to form an alkali conversion crystal slurry; step S300, continuously passing the pretreated nickel-cobalt slurry and the alkali conversion crystal slurry into a reactor for a nickel-cobalt precipitation reaction to obtain a nickel-cobalt precipitated slurry; step S400, continuously performing a dense separation treatment on the nickel-cobalt precipitated slurry to obtain a nickel-cobalt precipitation underflow and a nickel-cobalt precipitation overflow; the nickel-cobalt precipitation underflow is composed of the first nickel-cobalt precipitation underflow, the second nickel-cobalt precipitation underflow and the third nickel-cobalt precipitation underflow; the nickel-cobalt precipitation overflow includes the first nickel-cobalt precipitation overflow; step S500, filtering and washing the third nickel-cobalt precipitation underflow in sequence to obtain a nickel-cobalt hydroxide product.

[0032] The method for precipitating nickel and cobalt in the present application includes adding a first nickel and cobalt precipitate underflow to a nickel and cobalt-containing solution to carry out a seed pretreatment reaction, that is, a portion of the nickel and cobalt hydroxide precipitate is pre-mixed with the nickel and cobalt-containing solution as a seed, so that the magnesium and manganese in the nickel and cobalt hydroxide precipitate are fully replaced with the nickel and cobalt in the nickel and cobalt solution, the manganese and magnesium in the nickel and cobalt hydroxide precipitate are removed to a great extent, the aggregation and precipitation of nickel and cobalt ions in the solution are promoted, and a larger and more stable precipitation structure is formed, the particle size and sedimentation properties of the precipitate are improved, and finally a nickel and cobalt hydroxide product with better quality is obtained.

[0033] After the magnesium and manganese in the nickel-cobalt hydroxide precipitate and the nickel-cobalt in the nickel-cobalt solution have fully undergone a replacement reaction, the pretreated nickel-cobalt ore pulp and the alkali-transforming crystal slurry are continuously introduced into the reactor for nickel-cobalt precipitation reaction. In this process, the present invention does not use sulfide or sodium hydroxide as a strong base in the traditional precipitation reaction, nor does it directly use magnesium hydroxide with low activity. The precipitant used in the present invention is the alkali-transforming crystal slurry formed after the second nickel-cobalt precipitation underflow or the first nickel-cobalt precipitation overflow undergoes an alkali-transforming reaction with an alkaline precipitation inducer. As mentioned above, it is obtained by the alkali-transforming reaction of the second nickel-cobalt precipitation underflow or the first nickel-cobalt precipitation overflow obtained by the continuous precipitation reaction with an alkaline precipitation inducer. Specifically, an alkaline precipitation inducer is added to a part of the overflow obtained in the previous step (i.e., the first nickel-cobalt precipitation overflow) to undergo an alkali-transforming reaction to obtain an alkali-transforming crystal slurry; or, an alkaline precipitation inducer is added to a part of the underflow obtained in the previous step (i.e., the second nickel-cobalt precipitation underflow) to undergo an alkali-transforming reaction to form an alkali-transforming crystal slurry.

[0034] As mentioned above, in addition to the nickel ions and cobalt ions to be precipitated, the nickel-cobalt solution also contains a large amount of magnesium ions and divalent manganese ions. Accordingly, the nickel-cobalt precipitation underflow and the nickel-cobalt precipitation overflow generated in the previous process also contain a large amount of magnesium ions and divalent manganese ions. Adding an alkaline precipitation inducer to the second nickel-cobalt precipitation underflow or the first nickel-cobalt precipitation overflow can convert these magnesium ions and divalent manganese ions into magnesium hydroxide and manganese hydroxide. At the same time, since the present invention uses an alkaline precipitation inducer to prepare the alkali-transfer crystal slurry online during continuous alkali-transfer precipitation and continuous dense separation, the alkali-transfer crystal slurry with higher activity can be returned to the previous process in time to participate in the nickel-cobalt precipitation reaction, and it is also ensured that the alkali-transfer crystal slurry has a high precipitation activity. In addition, the alkali-transfer crystal slurry also contains a portion of the nickel-cobalt hydroxide generated in the previous process (from the second nickel-cobalt precipitation underflow), which can also play the role of a seed template in the nickel-cobalt precipitation reaction process to promote the precipitation and crystal growth of nickel-cobalt hydroxide.

[0035] Based on the above reasons, the present invention effectively solves the problems of small particle size of nickel cobalt hydroxide that is not easy to settle, high water content of filter cake, or poor precipitation rate when nickel cobalt is precipitated from nickel cobalt solution in the prior art, and high magnesium content before technical improvement. The method of precipitating nickel cobalt from the above nickel cobalt solution uses more environmentally friendly additives, has a high precipitation rate, and the nickel cobalt hydroxide product has a better morphology, a larger particle size, and good sedimentation ability, which is beneficial to the subsequent liquid-solid separation process, thereby reducing the water content of the nickel cobalt hydroxide product, and the obtained nickel cobalt hydroxide product has a lower content of magnesium ions and manganese ions.

[0036] In a preferred embodiment, in order to maintain better precipitation activity of the alkali-converted slurry and prevent it from aging after being left alone for a long time, the alkali-converted slurry is placed in step S300 to participate in the nickel-cobalt precipitation reaction within 5 minutes, more preferably within 3 minutes.

[0037] In one embodiment of the present application, in the above step S100, the temperature of the seed pretreatment reaction is 25°C to 100°C, preferably 50°C to 80°C, and the time of the seed pretreatment reaction is 0.1h to 10h, preferably 1h to 5h.

[0038] The optimal reaction temperature range can ensure the rate and conversion rate of the seed pretreatment reaction, so that the nickel and cobalt ions can be quickly and efficiently precipitated on the surface of the seed to form a precipitate with a larger particle size, thereby improving the efficiency of nickel and cobalt precipitation and product quality, and reducing energy consumption. Among them, the temperature of the seed pretreatment reaction can be 25°C, 30°C, 35°C, 40°C, 45°C, 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, 80°C, 85°C, 90°C, 95°C or 100°C, and is certainly not limited to any value between 25°C and 100°C. The time of the seed pretreatment reaction can be 0.1h, 1h, 1.5h, 2h, 3h, 4h, 5h, 6h, 8h, 9h or 10h, and is certainly not limited to any value between 0.1h and 10h.

[0039] In one embodiment of the present application, in the above step S100, the mass of the first nickel-cobalt precipitation underflow is 0.1% to 99% of the total mass of the nickel-cobalt precipitation underflow.

[0040] The quality of the first nickel-cobalt precipitation underflow is the ratio of the total mass of the nickel-cobalt precipitation underflow, which directly affects the effect of the seed pretreatment reaction. An appropriate amount of the first nickel-cobalt precipitation underflow can promote the formation of seed and the growth of precipitate, and improve the sedimentation performance of precipitate. By adjusting the ratio of the first nickel-cobalt precipitation underflow in the total mass of the nickel-cobalt precipitation underflow, the precipitation process can be optimized, the precipitation efficiency can be improved, and the flexibility of the process can be ensured at the same time, and the nickel-cobalt solution of different concentrations can be adapted. Wherein, the quality of the first nickel-cobalt precipitation underflow can be 0.1%, 1%, 2%, 3%, 4%, 5%, 6%, 8%, 10%, 12%, 15%, 18%, 20%, 25%, 28%, 30%, 35%, 35%, 40%, 45%, 50%, 55%, 60%, 70%, 80%, 90% or 99% of the total mass of the nickel-cobalt precipitation underflow, and is certainly not limited to any one value in 0.1%~99%.

[0041] The alkaline precipitation inducing agent is added in the form of an aqueous solution or a slurry. In order to make the alkali transfer reaction more stable and the formed alkali transfer slurry more active, in a preferred embodiment, in the above step S200, the total mass concentration of the alkaline precipitation inducing agent is 0.1% to 60%, preferably 3% to 20%, and further preferably 3% to 15%. The concentration is controlled within the above range, on the one hand, the alkali transfer reaction is more stable, and on the other hand, the concentration of the alkali transfer slurry is more suitable, thereby promoting the nickel-cobalt precipitation reaction to be more efficient and stable. Specifically, the concentration of the alkaline precipitation inducing agent directly affects the pH value in the solution. Selecting a reasonable concentration range helps to promote the effective precipitation of nickel-cobalt, avoid the coprecipitation of other impurity ions, and improve the efficiency of nickel-cobalt precipitation, thereby improving the purity of the product, while controlling the cost and reducing the impact on the environment. Among them, the total mass concentration of the alkaline precipitation inducer can be 0.1%, 1%, 2%, 3%, 4%, 5%, 6%, 8%, 10%, 12%, 15%, 18%, 20%, 25%, 28%, 30%, 35%, 35%, 40%, 45%, 50%, 55% or 60%, and is certainly not limited to any value between 0.1% and 60%.

[0042] In a preferred embodiment, in the above step S200, the alkaline precipitation inducing agent is a mixture of an alkaline substance and water, wherein the alkaline substance is selected from any one or more of sodium hydroxide, potassium hydroxide, calcium hydroxide, magnesium hydroxide, calcium oxide, magnesium oxide and carbonate.

[0043] By using the above precipitation inducer, the precipitation activity of the alkali-transformed slurry is more suitable, which can not only make the nickel and cobalt precipitate more stably, but also is beneficial to the better morphology of the nickel and cobalt hydroxide precipitate particles, easier liquid-solid separation, lower water content and lower manganese content in the final product.

[0044] Furthermore, in the above step S200, the alkaline substance is preferably a mixture of sodium hydroxide and potassium hydroxide, and the mass ratio of sodium hydroxide to potassium hydroxide is (1~4):(1~4). Compared with other alkaline precipitation inducers such as calcium oxide, calcium hydroxide or sodium hydroxide, the use of the composite precipitation inducer under the above weight ratio has a better effect on the alkali conversion slurry, and the combination with the seed template has a better promoting effect on improving the morphology, precipitation rate, particle size, etc. of nickel cobalt hydroxide during the alkali conversion precipitation process. Among them, the mass ratio of sodium hydroxide to potassium hydroxide can be 1:1, 1:4, 1:2 or 4:1, and of course it is not limited to any ratio of 1~4:1~4 for the mass ratio of sodium hydroxide to potassium hydroxide.

[0045] In order to make the nickel ions and cobalt ions in the mixed solution precipitate more fully, in a preferred embodiment, the total number of moles of hydroxide and carbonate required for nickel and cobalt precipitation in the nickel-cobalt slurry after the above pretreatment is used as a benchmark, and the total number of moles of hydroxide and / or carbonate in the alkaline precipitation inducer is 0.5 to 1.5 times the theoretical total number of moles. In the actual operation process, in order to further reduce the impurity content in the nickel-cobalt hydroxide product, such as magnesium, manganese, etc., it is preferred that the molar number of hydroxide in the precipitation inducer is 0.8 to 0.9 times the theoretical molar number. In such an operation, a part of the direct yield of nickel-cobalt hydroxide may be lost, but the product is purer.

[0046] In one embodiment of the present application, in the above step S200, the temperature of the alkali transfer reaction is 25°C~100°C, preferably 50°C~60°C, and the time of the alkali transfer reaction is 0.1min~30min, preferably 1min~10min, and further preferably 3min~5min.

[0047] Based on the kinetics of the alkali-transfer reaction, controlling the temperature and time of the alkali-transfer reaction within the above range is helpful to carry out the reaction under suitable conditions, improve the efficiency and quality of nickel-cobalt precipitation, and reduce energy consumption. Among them, the temperature of the alkali-transfer reaction can be 25°C, 30°C, 35°C, 40°C, 45°C, 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, 80°C, 85°C, 90°C, 95°C or 100°C, and is certainly not limited to any one of 25°C to 100°C. The time of the alkali-transfer reaction can be 0.1min, 1min, 2min, 3min, 4min, 5min, 6min, 8min, 10min, 12min, 14min, 16min, 18min, 20min, 23min, 25min, 28min or 30min, and is certainly not limited to any one of 0.1min to 30min.

[0048] In one embodiment of the present application, in the above step S200, the mass of the first nickel-cobalt precipitation overflow is 1% to 99% of the total mass of the nickel-cobalt precipitation overflow, and preferably 5% to 30%.

[0049] The control of the first nickel-cobalt precipitation overflow is based on the consideration of the logistics balance of the precipitation process. An appropriate amount of the first nickel-cobalt precipitation overflow helps to maintain the growth and sedimentation of the precipitate. Too much or too little overflow will affect the precipitation effect. Adjusting the mass proportion of the first nickel-cobalt precipitation overflow in the nickel-cobalt precipitation overflow helps to optimize the nickel-cobalt precipitation process, improve the nickel-cobalt precipitation efficiency, and achieve the flexibility and stability of the nickel-cobalt precipitation process, and adapt to nickel-cobalt solutions of different concentrations. Among them, the mass of the first nickel-cobalt precipitation overflow can be 1%, 2%, 3%, 4%, 5%, 6%, 8%, 10%, 12%, 15%, 18%, 20%, 25%, 28%, 30%, 35%, 35%, 40%, 45%, 50%, 55%, 60%, 70%, 80%, 90% or 99% of the total mass of the nickel-cobalt precipitation overflow, of course, not limited to any value between 1% and 99%.

[0050] In one embodiment of the present application, in the above step S200, the mass of the second nickel-cobalt precipitation underflow is 1% to 99% of the total mass of the nickel-cobalt precipitation underflow.

[0051] By controlling the mass proportion of the second nickel-cobalt precipitation underflow in the nickel-cobalt precipitation underflow, it is beneficial to optimize the nickel-cobalt precipitation process, improve the nickel-cobalt precipitation efficiency and product quality, and ensure the flexibility and stability of the nickel-cobalt precipitation process to adapt to nickel-cobalt solutions of different concentrations. Among them, the mass of the second nickel-cobalt precipitation underflow can be 1%, 2%, 3%, 4%, 5%, 6%, 8%, 10%, 12%, 15%, 18%, 20%, 25%, 28%, 30%, 35%, 35%, 40%, 45%, 50%, 55%, 60%, 70%, 80%, 90% or 99% of the total mass of the nickel-cobalt precipitation underflow, and of course is not limited to any value between 1% and 99%.

[0052] The active ingredients of the alkali-transforming slurry are mainly nickel cobalt hydroxide, magnesium hydroxide and manganese hydroxide. In order to make the alkali-transforming slurry have higher precipitation activity, in a preferred embodiment, when an alkaline precipitation inducing agent is added to the first nickel cobalt precipitation overflow to carry out alkali-transforming reaction and form alkali-transforming slurry, the mass ratio of the first nickel cobalt precipitation underflow, the second nickel cobalt precipitation underflow and the third nickel cobalt precipitation underflow is (55%~89%): (10%~40%): (1%~5%). By adjusting the mass ratio between the first nickel cobalt precipitation underflow, the second nickel cobalt precipitation underflow and the third nickel cobalt precipitation underflow, it is helpful to optimize the precipitation process, maintain the best growth state of the precipitate, optimize the sedimentation performance of the precipitate, improve the precipitation efficiency and product quality, and ensure the stability and operability of the process. Among them, the mass ratio of the first nickel-cobalt precipitation underflow, the second nickel-cobalt precipitation underflow and the third nickel-cobalt precipitation underflow can be 85%:10%:5%, 55%:40%:5% or 65%:30%:5%, and of course is not limited to any one value of (55%~89%):(10%~40%):(1%~5%).

[0053] In actual operation, the third nickel-cobalt precipitation underflow can be directly filtered and washed to obtain a nickel-cobalt hydroxide product with a low manganese content. When the first nickel-cobalt precipitation overflow participates in the alkali conversion reaction, the remaining nickel-cobalt precipitation overflow can be directly used for the second stage of nickel-cobalt precipitation. When the nickel-cobalt precipitation overflow does not participate in the alkali conversion reaction, it can be directly opened out for the second stage of nickel-cobalt precipitation (such as returning to the previous process such as the high-pressure acid leaching process of laterite nickel ore).

[0054] In order to make the magnesium ions and divalent manganese ions in the second nickel-cobalt precipitation underflow or the first nickel-cobalt precipitation overflow more fully converted into magnesium hydroxide and manganese hydroxide, in a preferred embodiment, the temperature of the above nickel-cobalt precipitation reaction is 50°C~70°C, and the time of the nickel-cobalt precipitation reaction is 0.5h~5h. Under this process condition, the alkali-transfer slurry finally formed has better nickel-cobalt precipitation activity and higher nickel-cobalt precipitation rate, reduces resource waste, and has a better promoting effect on the nickel-cobalt precipitation process in the mixed solution. By optimizing the precipitation conditions, including using seed pretreatment reaction and controlling the concentration and composition of the alkaline precipitation inducer, the precipitation rate of nickel-cobalt ions and the stability of the precipitate can be increased, so that the nickel-cobalt precipitation rate in the nickel-cobalt precipitation reaction is 70%~98%. Among them, the temperature of the nickel-cobalt precipitation reaction can be 50°C, 55°C, 60°C, 65°C or 70°C, of ​​course not limited to any one value of 50°C~70°C. The time of the nickel-cobalt precipitation reaction can be 0.5h, 1h, 1.2h, 1.5h, 1.8h, 2h, 2.5h, 3h, 3.5h, 4h, 4.5h or 5h, and is certainly not limited to any value between 0.5h and 5h. The nickel-cobalt precipitation rate in the nickel-cobalt precipitation reaction can be 70%, 72%, 74%, 76%, 78%, 80%, 82%, 83%, 85%, 86%, 87%, 88%, 90%, 95% or 98%, and is certainly not limited to any value between 70% and 98%.

[0055] The above-mentioned method for precipitating nickel and cobalt provided by the present invention can be carried out continuously. After the fresh nickel-cobalt-containing solution (such as the iron-aluminum removal solution of laterite nickel ore acid leaching) continuously enters the seed pretreatment reaction, it continuously enters the reactor and performs a nickel-cobalt precipitation reaction with the alkali-converting slurry returned from the later process. The obtained precipitation slurry continuously enters the liquid-solid separation stage to form an underflow and an overflow. Part of the underflow and the optional part of the overflow continuously participate in the alkali-converting reaction, and continuously forms the alkali-converting slurry to return to the previous process to participate in the nickel-cobalt precipitation reaction. In the initial stage of the operation of this method, the mixed solution can be first precipitated with sodium hydroxide. After the initial underflow and overflow are formed, the alkali-converting slurry of the present invention is prepared by the above-mentioned preparation process as a precipitant after stable operation.

[0056] The precipitation method of the present invention is used for nickel-cobalt solution, such as nickel-cobalt precipitation of laterite nickel ore acid leaching iron-aluminum removal solution, and is particularly suitable for the following solution, wherein the cationic components in the nickel-cobalt solution are as follows: nickel ion 0.1g / L~120g / L, cobalt ion 0.1g / L~120g / L, magnesium ion 0.5g / L~25g / L, divalent manganese ion 0.5g / L~10g / L, and further, preferably nickel ion 3g / L~5g / L, cobalt ion 0.2g / L~0.5g / L, magnesium ion 5g / L~8g / L, divalent manganese ion 2g / L~4g / L. By controlling the concentration range of metal ions in the solution, combined with seed pretreatment and alkali conversion reaction, the precipitation conditions can be optimized, the effective separation and recovery of nickel and cobalt can be achieved, and the co-precipitation risk of impurities such as magnesium and manganese can be reduced.

[0057] According to one aspect of the present invention, a nickel-cobalt hydroxide product is provided. The nickel-cobalt hydroxide product is prepared by the above-mentioned method of precipitating nickel-cobalt from a nickel-cobalt solution.

[0058] The nickel-cobalt hydroxide product prepared by the above method has an optimized nickel-cobalt precipitation process, avoiding the co-precipitation of other impurities, thereby ensuring the high purity and high nickel-cobalt content of the product, making it more suitable for battery materials and other industrial applications.

[0059] In one embodiment of the present application, the D50 particle size of the nickel cobalt hydroxide product is 20μm~60μm, the water content is 45%~55%, the nickel content is 39%~44%, the manganese content is 2%~4%, and the magnesium content is 0.05%~1.0%.

[0060] The nickel cobalt hydroxide product of the present invention has moderate D50 particle size and moisture content, a nickel content of up to 39% to 44%, a manganese content of no more than 4%, and a magnesium content of no more than 1.0%. These characteristics enable it to have good sedimentation performance and filter cake performance, and is suitable for the needs of battery materials and other industrial applications.

[0061] The present application is further described in detail below in conjunction with specific embodiments. These embodiments should not be construed as limiting the scope of protection claimed in the present application.

[0062] The object of treatment in the following examples is a laterite nickel ore acid leaching iron and aluminum removal solution (aqueous solution), the anion of which is sulfate ion, and the cation components are as follows:

[0063]

[0064] Example 1

[0065] Reference Figure 1The process flow chart of the method for precipitating nickel and cobalt in a nickel-cobalt-containing solution is shown, wherein the first nickel-cobalt precipitation underflow (i.e., the underflow after nickel and cobalt precipitation accounting for 85% of the total nickel-cobalt precipitation underflow in the back-end process) is added to the above laterite nickel ore acid leaching iron and aluminum removal solution, and the mixture is stirred and mixed at 70°C for 3.0h to complete the seed pretreatment reaction and form a pretreated nickel-cobalt ore slurry.

[0066] The pretreated nickel-cobalt slurry and the alkali-converting slurry prepared in the back-end process are continuously added to the reactor by convection to carry out nickel-cobalt precipitation reaction. The reaction time is 3.0 hours and the reaction temperature is 60°C to obtain nickel-cobalt precipitated slurry; the nickel-cobalt precipitated slurry is continuously sent to the thickener for thickening and separation treatment to obtain nickel-cobalt precipitation underflow and nickel-cobalt precipitation overflow. The nickel-cobalt precipitation underflow consists of the first nickel-cobalt precipitation underflow, the second nickel-cobalt precipitation underflow and the third nickel-cobalt precipitation underflow. The third nickel-cobalt precipitation underflow is filtered and washed to obtain the nickel-cobalt hydroxide product.

[0067] Prepare an alkaline precipitation inducer with a total mass concentration of 20%, which is a slurry formed by dissolving sodium hydroxide and potassium hydroxide in water at a mass ratio of 4:4; continuously pass the second nickel-cobalt precipitation underflow, which accounts for 10% of the nickel-cobalt precipitation underflow, into the alkali conversion reactor, add an alkaline precipitation inducer thereto for alkali conversion reaction, and take the theoretical molar number of hydroxide required for nickel-cobalt precipitation in the mixed solution as the benchmark, and the molar number of hydroxide in the precipitation inducer is 0.9 times the theoretical molar number. The temperature of the above alkali conversion reaction is 50°C, and the reaction time is 3 minutes to obtain alkali conversion slurry. The formed alkali conversion slurry is continuously returned to the nickel-cobalt precipitation reaction step to obtain nickel-cobalt precipitated ore slurry.

[0068] According to the test, the nickel-cobalt precipitation rate in the nickel-cobalt precipitation reaction was 85%, the D50 particle size of the nickel-cobalt hydroxide product was 45-55μm, the water content was 55%, the nickel content was 43%, the manganese content was 2%, and the magnesium content was 0.1%.

[0069] Example 2

[0070] Reference Figure 2 The process flow chart of the method for precipitating nickel and cobalt in a nickel-cobalt-containing solution is shown, wherein 30% of the underflow after nickel and cobalt precipitation in the back-end process is added to the above laterite nickel ore acid leaching iron and aluminum removal solution, and the mixture is stirred and mixed at 40°C for 10.0h to complete the seed pretreatment reaction and form a pretreated nickel-cobalt ore slurry.

[0071] The pretreated nickel-cobalt slurry and the alkali-converting slurry prepared in the back-end process are continuously added to the reactor by convection to carry out nickel-cobalt precipitation reaction. The reaction time is 1.0h and the reaction temperature is 70°C to obtain nickel-cobalt precipitated slurry; the nickel-cobalt precipitated slurry is continuously sent to the thickener for thickening and separation treatment to obtain nickel-cobalt precipitation underflow and nickel-cobalt precipitation overflow. The nickel-cobalt precipitation underflow consists of the first nickel-cobalt precipitation underflow, the second nickel-cobalt precipitation underflow and the third nickel-cobalt precipitation underflow, and the second nickel-cobalt precipitation underflow accounts for 0 in the nickel-cobalt precipitation underflow. The third nickel-cobalt precipitation underflow is filtered and washed to obtain a nickel-cobalt hydroxide product.

[0072] Prepare an alkaline precipitation inducer with a total mass concentration of 20%, which is a slurry formed by dissolving sodium hydroxide and potassium hydroxide in water at a mass ratio of...:4; continuously pass the first nickel-cobalt precipitation overflow accounting for 10% of the nickel-cobalt precipitation overflow into the alkali conversion reactor, add an alkaline precipitation inducer thereto for alkali conversion reaction, and take the theoretical molar number of hydroxide required for nickel-cobalt precipitation in the mixed solution as the basis, and the molar number of hydroxide in the precipitation inducer is 0.9 times the theoretical molar number. The temperature of the above alkali conversion reaction is 50°C, the reaction time is 3min, and the alkali conversion slurry is obtained. The formed alkali conversion slurry is continuously returned to the nickel-cobalt precipitation reaction step to obtain the nickel-cobalt precipitated ore slurry.

[0073] According to the test, the nickel-cobalt precipitation rate in the nickel-cobalt precipitation reaction was 86%, the D50 particle size of the nickel-cobalt hydroxide product was 45-55μm, the water content was 54%, the nickel content was 44%, the manganese content was 2.2%, and the magnesium content was 0.15%.

[0074] Example 3

[0075] The only difference between this embodiment and embodiment 1 is that the mass ratio of sodium hydroxide to potassium hydroxide is 1:4, the total mass concentration of the precipitation inducer is 25%, and finally a nickel cobalt hydroxide product is obtained.

[0076] According to the test, the nickel-cobalt precipitation rate in the nickel-cobalt precipitation reaction was 85%, the D50 particle size of the nickel-cobalt hydroxide product was 45-50μm, the water content was 56%, the nickel content was 43%, the manganese content was 2%, and the magnesium content was 0.1%.

[0077] Example 4

[0078] The only difference between this embodiment and embodiment 1 is that the mass ratio of sodium hydroxide to potassium hydroxide is 0.6:4, and a nickel cobalt hydroxide product is finally obtained.

[0079] According to the test, the nickel-cobalt precipitation rate in the nickel-cobalt precipitation reaction was 85%, the D50 particle size of the nickel-cobalt hydroxide product was 40~45μm, the water content was 58%, the nickel content was 43%, the manganese content was 2%, and the magnesium content was 0.1%.

[0080] Example 5

[0081] The only difference between this embodiment and embodiment 1 is that the precipitation inducer is magnesium oxide with a mass concentration of 10%, and a nickel cobalt hydroxide product is finally obtained.

[0082] According to the test, the nickel-cobalt precipitation rate in the nickel-cobalt precipitation reaction was 85%, the D50 particle size of the nickel-cobalt hydroxide product was 45-55μm, the water content was 53%, the nickel content was 41%, the manganese content was 3%, and the magnesium content was 0.5%.

[0083] Example 6

[0084] This embodiment is different from Embodiment 1 in that: the first nickel-cobalt precipitation underflow accounts for 55% of the total nickel-cobalt precipitation underflow, the mass ratio of the first nickel-cobalt precipitation underflow, the second nickel-cobalt precipitation underflow and the third nickel-cobalt precipitation underflow is 55:40:5, and a nickel-cobalt hydroxide product is finally obtained.

[0085] According to the test, the nickel-cobalt precipitation rate in the nickel-cobalt precipitation reaction was 85%, the D50 particle size of the nickel-cobalt hydroxide product was 45-55μm, the water content was 55%, the nickel content was 43%, the manganese content was 3%, and the magnesium content was 0.4%.

[0086] Example 7

[0087] This embodiment is different from Embodiment 1 in that: the first nickel-cobalt precipitation underflow accounts for 90% of the total nickel-cobalt precipitation underflow, the mass ratio of the first nickel-cobalt precipitation underflow, the second nickel-cobalt precipitation underflow and the third nickel-cobalt precipitation underflow is 90:5:5, and a nickel-cobalt hydroxide product is finally obtained.

[0088] According to the test, the nickel-cobalt precipitation rate in the nickel-cobalt precipitation reaction was 85%, the D50 particle size of the nickel-cobalt hydroxide product was 20-25μm, the water content was 65%, the nickel content was 43%, the manganese content was 2%, and the magnesium content was 0.1%.

[0089] Example 8

[0090] This embodiment is different from Embodiment 1 in that the temperature of the seed pretreatment reaction is 80° C., the time of the seed pretreatment reaction is 5 h, and finally a nickel cobalt hydroxide product is obtained.

[0091] According to the test, the nickel-cobalt precipitation rate in the nickel-cobalt precipitation reaction was 85%, the D50 particle size of the nickel-cobalt hydroxide product was 45-55μm, the water content was 55%, the nickel content was 44%, the manganese content was 1.5%, and the magnesium content was 0.05%.

[0092] Example 9

[0093] This embodiment is different from embodiment 1 in that the temperature of the alkali conversion reaction is 40° C., the time of the alkali conversion reaction is 10 min, and finally a nickel cobalt hydroxide product is obtained.

[0094] According to the test, the nickel-cobalt precipitation rate in the nickel-cobalt precipitation reaction was 78%, the D50 particle size of the nickel-cobalt hydroxide product was 45-55μm, the water content was 52%, the nickel content was 39%, the manganese content was 4%, and the magnesium content was 0.8%.

[0095] Example 10

[0096] This embodiment is different from embodiment 1 in that the temperature of the nickel-cobalt precipitation reaction is 50° C., the time of the nickel-cobalt precipitation reaction is 5 hours, and a nickel-cobalt hydroxide product is finally obtained.

[0097] According to the test, the nickel-cobalt precipitation rate in the nickel-cobalt precipitation reaction was 83%, the D50 particle size of the nickel-cobalt hydroxide product was 40~53μm, the water content was 56%, the nickel content was 42%, the manganese content was 4%, and the magnesium content was 1%.

[0098] Embodiment 11

[0099] This embodiment is different from Embodiment 1 in that: based on the theoretical molar number of hydroxide required for nickel-cobalt precipitation in the mixed solution, the molar number of hydroxide in the alkaline precipitation inducer is 0.8 times the theoretical molar number.

[0100] According to the test, the nickel-cobalt precipitation rate in the nickel-cobalt precipitation reaction was 80%, the D50 particle size of the nickel-cobalt hydroxide product was 45-55μm, the water content was 54%, the nickel content was 43.1%, the manganese content was 2.1%, and the magnesium content was 0.12%.

[0101] Example 12

[0102] This embodiment is different from Embodiment 1 in that: based on the theoretical molar number of hydroxide required for nickel-cobalt precipitation in the mixed solution, the molar number of hydroxide in the alkaline precipitation inducer is 1.2 times the theoretical molar number.

[0103] According to the test, the nickel-cobalt precipitation rate in the nickel-cobalt precipitation reaction was 98%, the D50 particle size of the nickel-cobalt hydroxide product was 45-55μm, the water content was 55%, the nickel content was 41%, the manganese content was 4%, and the magnesium content was 1%.

[0104] Example 13

[0105] This embodiment is different from embodiment 1 in that the alkali-converting slurry is continuously returned to the nickel-cobalt precipitation reaction step within 5 minutes to carry out the nickel-cobalt precipitation reaction.

[0106] According to the test, the nickel-cobalt precipitation rate in the nickel-cobalt precipitation reaction was 83%, the D50 particle size of the nickel-cobalt hydroxide product was 55-60μm, the water content was 53%, the nickel content was 42%, the manganese content was 2.5%, and the magnesium content was 0.4%.

[0107] Comparative Example 1

[0108] The first nickel-cobalt precipitation underflow (i.e., the underflow after nickel-cobalt precipitation accounting for 30% of the total nickel-cobalt precipitation underflow in the back-end process) was added to the above laterite nickel ore acid leaching iron-aluminum removal solution, and the mixture was stirred and mixed at 70°C for 3.0h to complete the seed pretreatment reaction and form a pretreated nickel-cobalt ore slurry.

[0109] The pretreated nickel-cobalt slurry and the pre-configured 20% sodium hydroxide aqueous solution are continuously added to the reactor by convection to directly carry out nickel-cobalt precipitation reaction. The reaction time is 3.0 hours and the reaction temperature is 60°C to obtain nickel-cobalt precipitated slurry; the nickel-cobalt precipitated slurry is continuously sent to the thickener for thickening and separation treatment to obtain nickel-cobalt precipitation underflow and nickel-cobalt precipitation overflow. The nickel-cobalt precipitation underflow consists of the first nickel-cobalt precipitation underflow, the second nickel-cobalt precipitation underflow and the third nickel-cobalt precipitation underflow. The third nickel-cobalt precipitation underflow is filtered and washed to obtain a nickel-cobalt hydroxide product.

[0110] According to the test, the nickel-cobalt precipitation rate in the nickel-cobalt precipitation reaction was 85%, the D50 particle size of the nickel-cobalt hydroxide product was 3~5μm, the water content was 75%, the nickel content was 36%, the manganese content was 5%, and the magnesium content was 1.2%.

[0111] Comparative Example 2

[0112] The above laterite nickel ore acid leaching iron and aluminum removal solution and the alkali conversion slurry prepared in the back-end process are continuously added to the reactor by convection to directly carry out nickel-cobalt precipitation reaction. The reaction time is 3.0 hours and the reaction temperature is 60°C to obtain nickel-cobalt precipitated slurry; the nickel-cobalt precipitated slurry is continuously sent to the thickener for thickening and separation treatment to obtain nickel-cobalt precipitation underflow and nickel-cobalt precipitation overflow. The nickel-cobalt precipitation underflow consists of the first nickel-cobalt precipitation underflow, the second nickel-cobalt precipitation underflow and the third nickel-cobalt precipitation underflow. The third nickel-cobalt precipitation underflow is filtered and washed to obtain a nickel-cobalt hydroxide product.

[0113] Prepare an alkaline precipitation inducer with a total mass concentration of 20%, which is a slurry formed by dissolving sodium hydroxide and potassium hydroxide in water at a mass ratio of 4:4; continuously pass the second nickel-cobalt precipitation underflow, which accounts for 5% of the nickel-cobalt precipitation underflow, into the alkali conversion reactor, add an alkaline precipitation inducer thereto for alkali conversion reaction, and take the theoretical molar number of hydroxide required for nickel-cobalt precipitation in the mixed solution as the benchmark, and the molar number of hydroxide in the precipitation inducer is 0.9 times the theoretical molar number. The temperature of the above alkali conversion reaction is 70°C, and the reaction time is 1min to obtain alkali conversion slurry. The formed alkali conversion slurry is continuously returned to the nickel-cobalt precipitation reaction step to obtain nickel-cobalt precipitated ore slurry.

[0114] According to the test, the nickel-cobalt precipitation rate in the nickel-cobalt precipitation reaction was 89%, the D50 particle size of the nickel-cobalt hydroxide product was 45~55μm, the water content was 55%, the nickel content was 39%, the manganese content was 7%, and the magnesium content was 2.5%.

[0115] From the above description, it can be seen that the above embodiments of the present invention achieve the following technical effects:

[0116] The method for precipitating nickel and cobalt in the present application includes adding a first nickel and cobalt precipitate underflow to a nickel and cobalt-containing solution to carry out a seed pretreatment reaction, that is, a portion of the nickel and cobalt hydroxide precipitate is pre-mixed with the nickel and cobalt-containing solution as a seed, so that the magnesium and manganese in the nickel and cobalt hydroxide precipitate are fully replaced with the nickel and cobalt in the nickel and cobalt solution, the manganese and magnesium in the nickel and cobalt hydroxide precipitate are removed to a great extent, the aggregation and precipitation of nickel and cobalt ions in the solution are promoted, and a larger and more stable precipitation structure is formed, the particle size and sedimentation properties of the precipitate are improved, and finally a nickel and cobalt hydroxide product with better quality is obtained.

[0117] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for precipitating nickel and cobalt from a nickel-cobalt solution, wherein the cations in the nickel-cobalt solution include nickel ions, cobalt ions, magnesium ions and manganese ions, characterized in that: The method comprises: Step S100, using a first nickel-cobalt precipitation underflow to perform a seed pretreatment reaction on the nickel-cobalt-containing solution to form a pretreated nickel-cobalt slurry; Step S200, adding an alkaline precipitation inducing agent to the second nickel-cobalt precipitation underflow to perform a alkali conversion reaction to form an alkali conversion slurry; or, adding an alkaline precipitation inducing agent to the first nickel-cobalt precipitation overflow to perform a alkali conversion reaction to form an alkali conversion slurry; Step S300, continuously introducing the pretreated nickel-cobalt slurry and the alkali-converted crystal slurry into a reactor to perform a nickel-cobalt precipitation reaction to obtain a nickel-cobalt precipitated slurry; Step S400, continuously performing a thickening and separation treatment on the nickel-cobalt precipitated slurry to obtain a nickel-cobalt precipitated underflow and a nickel-cobalt precipitated overflow; the nickel-cobalt precipitated underflow is composed of the first nickel-cobalt precipitated underflow, the second nickel-cobalt precipitated underflow and the third nickel-cobalt precipitated underflow; the nickel-cobalt precipitated overflow includes the first nickel-cobalt precipitated overflow; Step S500, filtering and washing the third nickel-cobalt precipitate underflow in sequence to obtain a nickel-cobalt hydroxide product; The cationic components in the nickel-cobalt solution are as follows: nickel ions 3g / L-5g / L, cobalt ions 0.2g / L-0.5g / L, magnesium ions 5g / L-8g / L, and divalent manganese ions 2g / L-4g / L.

2. The method for precipitating nickel and cobalt from a nickel-cobalt solution according to claim 1, characterized in that: In the step S100, the temperature of the seed crystal pretreatment reaction is 25° C. to 100° C., and the time of the seed crystal pretreatment reaction is 0.1 h to 10 h.

3. The method for precipitating nickel and cobalt from a nickel and cobalt-containing solution according to claim 1 or 2, characterized in that: In the step S100, the mass of the first nickel-cobalt precipitation underflow is 1% to 99% of the total mass of the nickel-cobalt precipitation underflow.

4. The method for precipitating nickel and cobalt from a nickel and cobalt-containing solution according to claim 1 or 2, characterized in that: In the step S200, the total mass concentration of the alkaline precipitation inducer is 0.1% to 60%.

5. The method for precipitating nickel and cobalt from a nickel-cobalt solution according to claim 4, characterized in that: In step S200, the alkaline precipitation inducing agent is a mixed solution formed by an alkaline substance and water, wherein the alkaline substance is selected from any one or more of sodium hydroxide, potassium hydroxide, calcium hydroxide, magnesium hydroxide, calcium oxide, magnesium oxide and carbonate.

6. The method for precipitating nickel and cobalt from a nickel and cobalt-containing solution according to claim 5, characterized in that: In step S200, the alkaline substance is a mixture of the sodium hydroxide and the potassium hydroxide, and the mass ratio of the sodium hydroxide to the potassium hydroxide is (1-4):(1-4).

7. The method for precipitating nickel and cobalt from a nickel and cobalt-containing solution according to claim 1 or 2, characterized in that: Based on the theoretical total number of moles of hydroxide and / or carbonate required for nickel-cobalt precipitation in the pretreated nickel-cobalt slurry, the total number of moles of hydroxide and carbonate in the alkaline precipitation inducer is 0.5 to 1.5 times the theoretical total number of moles.

8. The method for precipitating nickel and cobalt from a nickel and cobalt-containing solution according to claim 1 or 2, characterized in that: In the step S200, the temperature of the alkali transfer reaction is 25-100° C., and the time of the alkali transfer reaction is 0.1-30 min.

9. The method for precipitating nickel and cobalt from a nickel-cobalt solution according to claim 1 or 2, characterized in that: In the step S200, the mass of the first nickel-cobalt precipitation overflow is 1% to 99% of the total mass of the nickel-cobalt precipitation overflow.

10. The method for precipitating nickel and cobalt from a nickel and cobalt-containing solution according to claim 1 or 2, characterized in that: In the step S200, the mass of the second nickel-cobalt precipitation underflow is 1% to 99% of the total mass of the nickel-cobalt precipitation underflow.

11. The method for precipitating nickel and cobalt from a nickel and cobalt-containing solution according to claim 1 or 2, characterized in that: When the alkaline precipitation inducer is added to the first nickel-cobalt precipitation overflow to carry out the alkaline conversion reaction and form the alkaline conversion slurry, the mass ratio of the first nickel-cobalt precipitation underflow, the second nickel-cobalt precipitation underflow and the third nickel-cobalt precipitation underflow is (55%~89%): (10%~40%): (1%~5%).

12. The method for precipitating nickel and cobalt from a nickel and cobalt-containing solution according to claim 1 or 2, characterized in that: The temperature of the nickel-cobalt precipitation reaction is 50-70° C., the time of the nickel-cobalt precipitation reaction is 0.5 h-5 h, and the nickel-cobalt precipitation rate in the nickel-cobalt precipitation reaction is 70%-98%.

13. The method for precipitating nickel and cobalt from a nickel and cobalt-containing solution according to claim 1 or 2, characterized in that: The nickel cobalt hydroxide product has a D50 particle size of 20-60 μm, a moisture content of 45-55%, a nickel content of 39-44%, a manganese content of 2-4%, and a magnesium content of 0.05-1.0%.

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