阅读说明：本技术 一种氢氧化镍及其制备方法 (Nickel hydroxide and preparation method thereof ) 是由 王博宇 刘增威 胡石春 肖超 訚硕 于 2021-09-28 设计创作，主要内容包括：本申请提供一种氢氧化镍及其制备方法,该氢氧化镍的制备方法沉镍碱源辅料采用低活性氧化镁,低活性氧化镁通过球料体积比(30～50)：1,液固体积比(2～5)：1,湿磨时间0.5～3.0h,湿磨预处理提高低活性氧化镁的活性,使其能够达到高活性氧化镁的沉镍效果,相比高活性氧化镁辅料,低活性氧化镁的成本低廉,该工艺流程简单、产品含镍高。(The application provides nickel hydroxide and a preparation method thereof, the nickel hydroxide precipitation alkali source auxiliary material adopts low-activity magnesium oxide, and the volume ratio of the low-activity magnesium oxide to a ball material is (30-50): 1, liquid-solid volume ratio (2-5): 1, wet-milling time is 0.5-3.0 h, the activity of low-activity magnesium oxide is improved by wet-milling pretreatment, so that the high-activity magnesium oxide can reach the nickel precipitation effect, compared with high-activity magnesium oxide auxiliary materials, the low-activity magnesium oxide is low in cost, the process flow is simple, and the product contains high nickel.)

1. A method for preparing nickel hydroxide, comprising:

the laterite-nickel ore is subjected to high-pressure acid leaching to obtain a nickel sulfate solution;

carrying out wet grinding treatment on low-activity magnesium oxide by using a ball mill to obtain magnesium oxide slurry, wherein the ball material volume ratio (30-50) in the wet grinding process is as follows: 1, liquid-solid volume ratio (2-5): 1, wet grinding for 0.5-3.0 h;

adding the magnesium oxide slurry into the nickel sulfate solution to react to obtain nickel precipitation slurry;

carrying out solid-liquid separation on the nickel precipitation slurry to obtain a nickel precipitation solution and a nickel hydroxide filter cake;

and drying the nickel hydroxide filter cake to obtain the nickel hydroxide.

2. The method of claim 1, wherein the low-activity magnesium oxide is an active-60 and/or active-40 magnesium oxide.

3. The method of claim 2, wherein the low-activity magnesium oxide has an iodine absorption value of 40 to 80 (mgI)₂/gMgO), the bulk density is less than or equal to 0.12g/mL, and the MgO is more than or equal to 92 percent.

4. The method for preparing nickel hydroxide according to claim 1, wherein the step of adding the magnesium oxide slurry into the nickel sulfate solution to react to obtain the precipitated nickel slurry specifically comprises:

and adding the magnesium oxide slurry into the nickel sulfate solution to adjust the pH value to 7.5-9.0, and reacting for 1-5 h.

5. The method according to claim 4, wherein the pH is 7.5 to 8.0 and the reaction time is 3 to 4 hours.

6. The method for preparing nickel hydroxide according to claim 1, wherein the ball volume ratio in the wet grinding process (35-40): 1, liquid-solid volume ratio (4-5): 1, wet grinding time is 2.0-3.0 h.

7. The method for preparing nickel hydroxide according to any one of claims 1 to 6, wherein the post-nickel-precipitation solution is treated with a heavy metal scavenger having a volume concentration of 15 to 50%.

8. The method for preparing nickel hydroxide according to claim 7, wherein the heavy metal trapping agent is a composite organic matter LD-1MS, and the mass ratio of the composite organic matter LD-1MS to Ni, Co and Mn in the nickel-precipitated solution is (1.01-1.1): 1.

9. the method for preparing nickel hydroxide according to claim 8, wherein the mass ratio of the composite organic matter LD-1MS to Ni, Co and Mn in the nickel precipitation solution is (1.01-1.05): 1.

10. a nickel hydroxide, characterized by being produced by the method for producing a nickel hydroxide according to any one of claims 1 to 9.

Technical Field

The application relates to the technical field of hydrometallurgy, in particular to nickel hydroxide and a preparation method thereof.

Background

Along with the gradual depletion of nickel sulfide ore resources, the efficient development of the laterite-nickel ore which accounts for 60 percent of the global nickel resources is increasingly urgent. The hydrometallurgy of the laterite-nickel ore generally adopts sulfuric acid leaching, the metals such as Ni, Co, Mn, Al, Mg and the like are extracted into solution, and then a series of impurity removal processes are carried out to obtain preliminarily purified nickel sulfate solution; at present, the sodium hydroxide is generally adopted for recovering nickel in a nickel sulfate solution for precipitation, but the alkalinity of the sodium hydroxide is too high, so that the phenomenon of over-alkali in a precipitation tank is easily caused in the actual production, most impurities are precipitated together and brought into a product, the main content of nickel in the nickel hydroxide is reduced, and the defects of small particle size and difficult filtration of precipitates exist simultaneously.

In the prior art, magnesium oxide is adopted for precipitation to produce nickel hydroxide, but the magnesium oxide has high cost, so that the production cost of the nickel hydroxide is high, and the industrial application is not facilitated.

Disclosure of Invention

The application aims to provide nickel hydroxide and a preparation method thereof, and aims to solve the problem that the existing magnesium oxide precipitated nickel hydroxide is high in cost.

To achieve the above object, the present application provides a method for preparing nickel hydroxide, comprising:

the laterite-nickel ore is subjected to high-pressure acid leaching to obtain a nickel sulfate solution;

carrying out wet grinding treatment on low-activity magnesium oxide by using a ball mill to obtain magnesium oxide slurry, wherein the ball material volume ratio (30-50) in the wet grinding process is as follows: 1, liquid-solid volume ratio (2-5): 1, wet grinding for 0.5-3.0 h;

adding magnesium oxide slurry into a nickel sulfate solution to react to obtain nickel precipitation slurry;

carrying out solid-liquid separation on the nickel precipitation slurry to obtain a nickel precipitation solution and a nickel hydroxide filter cake;

and drying the nickel hydroxide filter cake to obtain the nickel hydroxide.

Preferably, the low activity magnesium oxide is an active-60 and/or an active-40 magnesium oxide.

Preferably, the iodine absorption value of the low-activity magnesium oxide is 40-80 (mgI)₂/gMgO), the bulk density is less than or equal to 0.12g/mL, and the MgO is more than or equal to 92 percent.

Preferably, the step of adding the magnesium oxide slurry into the nickel sulfate solution to react to obtain the nickel precipitation slurry specifically comprises the following steps:

adding magnesium oxide slurry into the nickel sulfate solution to adjust the pH value to 7.5-9.0, and reacting for 1-5 h.

Preferably, the pH value is 7.5-8.0, and the reaction time is 3-4 h.

Preferably, the volume ratio of the ball materials in the wet grinding process is (35-40): 1, liquid-solid volume ratio (4-5): 1, wet grinding time is 2.0-3.0 h.

Preferably, the liquid after nickel deposition is treated by a heavy metal capture agent with the volume concentration of 15-50%.

Preferably, the heavy metal trapping agent is a composite organic matter LD-1MS, and the mass ratio of the composite organic matter LD-1MS to Ni, Co and Mn in the nickel-precipitated solution is (1.01-1.1): 1.

preferably, the mass ratio of the composite organic matter LD-1MS to Ni, Co and Mn in the nickel-precipitated liquid is (1.01-1.05): 1.

the application also provides nickel hydroxide prepared by the preparation method of nickel hydroxide.

Compared with the prior art, the beneficial effect of this application includes:

the preparation method of nickel hydroxide provided by the application adopts low-activity magnesium oxide as the alkali source auxiliary material, the cost of the low-activity magnesium oxide is only 2500 yuan/ton, the cost of the high-activity magnesium oxide reaches 4000-8000 yuan/ton, the activity of the low-activity magnesium oxide is improved through wet grinding pretreatment, the nickel precipitation effect of the high-activity magnesium oxide can be achieved, and compared with the high-activity magnesium oxide auxiliary material, the preparation method is low in cost, simple in process flow and high in nickel content of the product.

Drawings

To more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are required to be used in the embodiments are briefly described below, and it should be understood that the following drawings only illustrate some embodiments of the present application and therefore should not be considered as limiting the scope of the present application.

FIG. 1 is a schematic flow diagram of a process for preparing nickel hydroxide in accordance with the present invention;

FIG. 2 is a schematic view of a specific process flow of the method for preparing nickel hydroxide according to the present invention.

Detailed Description

The terms as used herein:

"prepared from … …" is synonymous with "comprising". The terms "comprises," "comprising," "includes," "including," "has," "having," "contains," "containing," or any other variation thereof, as used herein, are intended to cover a non-exclusive inclusion. For example, a composition, process, method, article, or apparatus that comprises a list of elements is not necessarily limited to only those elements but may include other elements not expressly listed or inherent to such composition, process, method, article, or apparatus.

The conjunction "consisting of … …" excludes any unspecified elements, steps or components. If used in a claim, the phrase is intended to claim as closed, meaning that it does not contain materials other than those described, except for the conventional impurities associated therewith. When the phrase "consisting of … …" appears in a clause of the subject matter of the claims rather than immediately after the subject matter, it defines only the elements described in the clause; other elements are not excluded from the claims as a whole.

When an amount, concentration, or other value or parameter is expressed as a range, preferred range, or as a range of upper preferable values and lower preferable values, this is to be understood as specifically disclosing all ranges formed from any pair of any upper range limit or preferred value and any lower range limit or preferred value, regardless of whether ranges are separately disclosed. For example, when the range "1 ~ 5" is disclosed, the ranges described should be construed to include the ranges "1 ~ 4", "1 ~ 3", "1 ~ 2 and 4 ~ 5", "1 ~ 3 and 5", and the like. When a range of values is described herein, unless otherwise stated, the range is intended to include the endpoints thereof and all integers and fractions within the range.

In these examples, the parts and percentages are by mass unless otherwise indicated.

"part by mass" means a basic unit of measure indicating a mass ratio of a plurality of components, and 1 part may represent any unit mass, for example, 1g or 2.689 g. If we say that the part by mass of the component A is a part by mass and the part by mass of the component B is B part by mass, the ratio of the part by mass of the component A to the part by mass of the component B is a: b. alternatively, the mass of the A component is aK and the mass of the B component is bK (K is an arbitrary number, and represents a multiple factor). It is unmistakable that, unlike the parts by mass, the sum of the parts by mass of all the components is not limited to 100 parts.

"and/or" is used to indicate that one or both of the illustrated conditions may occur, e.g., a and/or B includes (a and B) and (a or B).

The present application provides a method for preparing nickel hydroxide, referring to fig. 1 and 2, comprising:

the first step is as follows: and (3) leaching the laterite-nickel ore by high-pressure acid to obtain a nickel sulfate solution.

Specifically, the laterite-nickel ore is subjected to steps of crushing, ore washing, ore pulp concentration and the like, and then concentrated sulfuric acid is used for high-pressure acid leaching and neutralizing iron and aluminum removal to obtain a nickel sulfate solution, wherein the nickel sulfate solution mainly contains nickel ions, cobalt ions and manganese ions.

The second step is that: carrying out wet grinding treatment on low-activity magnesium oxide by using a ball mill to obtain magnesium oxide slurry, wherein the ball material volume ratio (30-50) in the wet grinding process is as follows: 1, liquid-solid volume ratio (2-5): 1, wet grinding time is 0.5-3.0 h.

Specifically, the indexes of the active magnesium oxide such as chemical composition, physical form and the like are not greatly different from those of the common magnesium oxide, but part of the indexes of the active magnesium oxide are different from those of the common magnesium oxide in requirements, for example, the active magnesium oxide has proper particle size distribution, and the micro form is irregular particles or nearly spherical particles or flaky crystals. The active magnesium oxide of the embodiment of the invention meets the standards of HG/T3928-.

Specifically, the low-activity magnesium oxide in the embodiment of the present invention is defined as "activity-60" and "activity-40" in HG/T3928-2012 standard, and the low-activity magnesium oxide may be, for example, "activity-60" active magnesium oxide, or "activity-40" active magnesium oxide, or "activity-60" and "activity-40" active magnesium oxide. And the active magnesium oxide of the HG/T3928-2012 standard is high-activity magnesium oxide of 'activity-80', 'activity-120', 'activity 150' and 'activity-180'.

Specifically, the iodine absorption value of the low-activity magnesium oxide is 40-80 (mgI)₂/gMgO), in which "active-40" is presentThe iodine absorption value of the active magnesium oxide is 40.1-60 (mgI)₂(gMgO), the iodine absorption value of the active magnesium oxide of active-60 is 60.1-80 (mgI)₂/gMgO)。

The bulk density of the low-activity magnesium oxide in the embodiment of the invention is less than or equal to 0.12g/mL, and the MgO is more than or equal to 92%.

The activity of the low-activity magnesium oxide is not as good as that of the high-activity magnesium oxide, but the price of the low-activity magnesium oxide is more advantageous than that of the high-activity magnesium oxide, the low-activity magnesium oxide only needs 2500 yuan/ton, the price of the high-activity magnesium oxide reaches 4000-8000 yuan/ton, and the price difference is larger.

The preparation method of the nickel hydroxide adopts the low-activity magnesium oxide to precipitate the nickel, has low cost, and can improve the activity of the low-activity magnesium oxide through pretreatment so as to achieve the nickel precipitation effect of the high-activity magnesium oxide in order to ensure the nickel precipitation effect.

The preparation method of the nickel hydroxide adopts a ball mill to carry out wet milling treatment to improve the activity of magnesium oxide, and the volume ratio of ball materials in the wet milling process is (30-50): 1, for example, (30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, or 50): 1.

liquid-solid volume ratio (2-5): 1, for example, (2, 2.1, 2.2, 2.3, 2.5, 2.8, 2.9, 3.0, 3.2, 3.4, 3.6, 3.8, 4.0, 4.3, 4.6, 4.7, 4.8, 4.9 or 5): 1.

the wet milling time is 0.5 to 3.0 hours, and may be (0.5, 0.6, 0.8, 0.9, 1.0, 1.2, 1.4, 1.5, 1.7, 1.8, 2.0, 2.3, 2.4, 2.6, 2.7, 2.9, or 3.0) hours, for example.

Preferably, the volume ratio of the ball materials in the wet grinding process is (35-40): 1, liquid-solid volume ratio (4-5): 1, wet grinding time is 2.0-3.0 h.

Experiments show that the low-activity magnesium oxide is subjected to mechanical grinding and activation aiming at specific ball-material ratio, liquid-solid ratio and grinding time, the mechanical activation process is improperly controlled, and the activity excitation and nickel precipitation effects of the magnesium oxide can be greatly reduced. And the magnesium oxide is activated by mechanical grinding without adding a modifier, so that the nickel hydroxide product is not influenced.

The third step: adding magnesium oxide slurry into the nickel sulfate solution to react to obtain the nickel precipitation slurry.

Specifically, magnesium oxide slurry is added into a 40-60 ℃ precipitation tank filled with a nickel sulfate solution to adjust the pH value of the nickel sulfate solution to 7.5-9.0, and the stable reaction is carried out for 1-5 hours.

For example, the pH may be 7.5, 7.6, 7.8, 8.0, 8.2, 8.3, 8.5, 8.6, 8.8, 8.9 or 9.0, reaction (1, 2, 3, 4 or 5) h.

Preferably, magnesium oxide slurry is added to adjust the pH value of the nickel sulfate solution to 7.5-8.0, and the reaction time is 3-4 h.

The fourth step: and carrying out solid-liquid separation on the nickel precipitation slurry to obtain a nickel precipitation solution and a nickel hydroxide filter cake.

Specifically, the nickel precipitation slurry is subjected to filter pressing and solid-liquid separation to obtain a nickel precipitation solution and a nickel hydroxide filter cake.

Further, the liquid after nickel precipitation is treated by a heavy metal capturing agent with the volume concentration of 15-50%, the heavy metal capturing agent is commonly used for industrial wastewater and solid waste treatment, can be strongly chelated with heavy metal ions, the molecular weight is generally hundreds, and the chelating groups of the heavy metal capturing agent and the heavy metal ions can form stable and water-insoluble chelated precipitates, so that the purpose of separating the heavy metal ions is achieved, and the heavy metal ions Ni, Co and Mn in the liquid after nickel precipitation are recovered. The heavy metal scavenger can be, for example, a complex organic substance LD-1MS, which is a complex organic sulfur mixture available from Linovi Biotech, Inc., Nanjing.

Preferably, the mass ratio of the composite organic matter LD-1MS to Ni, Co and Mn in the nickel-precipitated liquid is (1.01-1.1): 1.

more preferably, the mass ratio of the composite organic matter LD-1MS to Ni, Co and Mn in the nickel-precipitated solution is (1.01-1.05): 1.

the fifth step: and drying the nickel hydroxide filter cake to obtain the nickel hydroxide.

The preparation method of nickel hydroxide provided by the application adopts low-activity magnesium oxide as the alkali source auxiliary material, the cost of the low-activity magnesium oxide is only 2500 yuan/ton, the cost of the high-activity magnesium oxide reaches 4000-8000 yuan/ton, the activity of the low-activity magnesium oxide is improved through wet grinding pretreatment, the nickel precipitation effect of the high-activity magnesium oxide can be achieved, and compared with the high-activity magnesium oxide auxiliary material, the preparation method is low in cost, simple in process flow and high in nickel content of the product.

The application also provides nickel hydroxide prepared by the preparation method of nickel hydroxide.

Embodiments of the present application will be described in detail below with reference to specific examples, but those skilled in the art will appreciate that the following examples are only illustrative of the present application and should not be construed as limiting the scope of the present application. The examples, in which specific conditions are not specified, were conducted under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products available commercially.

Example 1

The components of the nickel sulfate solution obtained by carrying out high-pressure acid leaching and iron and aluminum removal on the laterite-nickel ore are shown in the following table 1.

TABLE 1 ingredient table of nickel sulfate solution to be precipitated

Ni g/L	Fe g/L	Al	Co	Mn	pH
						3.51	0.002	0.003g/L	0.42	0.57	4.4

Adding "active-40" magnesium oxide (iodine absorption value of 66 mgI)₂MgO, bulk density 0.10g/mL, MgO92.3%) is wet-milled by a ball mill, and the liquid-solid volume ratio is 4: 1, ball material volume ratio of 40: and 1, grinding for 2h to obtain magnesium oxide slurry.

Slowly pumping the magnesium oxide slurry into a nickel precipitation tank filled with a nickel sulfate solution, adjusting the pH value of the nickel precipitation tank to 7.5, and stably stirring for reaction for 3 hours to obtain the nickel precipitation slurry.

And (3) after the reaction, carrying out filter pressing solid-liquid separation on the nickel precipitation slurry to obtain a nickel precipitation solution and a nickel hydroxide filter cake, and sending the nickel hydroxide filter cake to a drying process to obtain the nickel hydroxide product in the embodiment 1.

And (3) carrying out mixed reaction on a composite organic matter LD-1MS with the volume concentration of 20% and a nickel-precipitated solution, wherein the mass ratio of the LD-1MS to (Ni + Co + Mn) is 1.03: 1, filtering after reaction to obtain filter residue and filtrate, and returning the filter residue to high-pressure acid leaching for recycling; and (3) precipitating magnesium from the filtrate by using lime cream, discarding magnesium precipitation slag, and returning the magnesium precipitation liquid to a workshop for recycling.

Through detection, the nickel precipitation rate in the process of precipitating the nickel by the active-40 magnesium oxide in the example 1 reaches 99.76 percent, and the comprehensive recovery rate of (Ni + Co + Mn) reaches 99.93 percent.

Example 2

The nickel sulfate solution of example 1 was treated.

Adding "active-60" magnesium oxide (iodine absorption value of 69 mgI)₂MgO/gMgO, bulk density 0.14g/mL, MgO 92.47%) is wet-milled by a ball mill, and the liquid-solid volume ratio is 5: 1, ball material volume ratio 35: and (1) grinding for 3h to obtain magnesium oxide slurry.

Slowly pumping the magnesium oxide slurry into a nickel precipitation tank filled with a nickel sulfate solution, adjusting the pH value of the nickel precipitation tank to 8.0, and stably stirring for reaction for 4 hours to obtain the nickel precipitation slurry.

And (3) after the reaction, carrying out filter pressing solid-liquid separation on the nickel precipitation slurry to obtain a nickel precipitation solution and a nickel hydroxide filter cake, and sending the nickel hydroxide filter cake to a drying process to obtain the nickel hydroxide product of the embodiment 2.

And (3) carrying out mixed reaction on a composite organic matter LD-1MS with the volume concentration of 30% and a nickel-precipitated solution, wherein the mass ratio of the LD-1MS to (Ni + Co + Mn) is 1.04: 1, filtering after reaction to obtain filter residue and filtrate, and returning the filter residue to high-pressure acid leaching for recycling; and (3) precipitating magnesium from the filtrate by using lime cream, discarding magnesium precipitation slag, and returning the magnesium precipitation liquid to a workshop for recycling.

Through detection, the nickel deposition rate in the magnesium oxide nickel deposition reaches 99.81%, and the comprehensive recovery rate of (Ni + Co + Mn) reaches 99.96%.

Comparative example 1

The nickel sulfate solution of example 1 was treated.

Adding "active-40" magnesium oxide (iodine absorption value of 66 mgI)₂gMgO, bulk density 0.10g/mL, MgO92.3%) is processed by dry milling in a ball mill, and the volume ratio of ball materials is 40: 1, grinding for 2h, wherein the magnesium oxide after grinding is mixed according to a liquid-solid volume ratio of 4: 1, mixing to obtain magnesium oxide slurry.

Slowly pumping the magnesium oxide slurry into a nickel precipitation tank filled with a nickel sulfate solution, adjusting the pH value of the nickel precipitation tank to 7.5, and stably stirring for reaction for 3 hours to obtain the nickel precipitation slurry.

And (3) after the reaction, carrying out filter pressing solid-liquid separation on the nickel precipitation slurry to obtain a nickel precipitation solution and a nickel hydroxide filter cake, and sending the nickel hydroxide filter cake to a drying procedure to obtain the nickel hydroxide product of the comparative example 1.

And (3) carrying out mixed reaction on a composite organic matter LD-1MS with the volume concentration of 20% and a nickel-precipitated solution, wherein the mass ratio of the LD-1MS to (Ni + Co + Mn) is 1.03: 1, filtering after reaction to obtain filter residue and filtrate, and returning the filter residue to high-pressure acid leaching for recycling; and (3) precipitating magnesium from the filtrate by using lime cream, discarding magnesium precipitation slag, and returning the magnesium precipitation liquid to a workshop for recycling.

The detection proves that the nickel precipitation rate in the magnesium oxide nickel precipitation is only 83.54 percent. The magnesium oxide pretreatment is proved to be required to be wet grinding treatment, the materials are bonded with the grinding balls in the dry grinding process, the modification effect is poor, the dry grinding pretreatment does not accord with the actual production condition, and the nickel precipitation rate is poor.

Comparative example 2

For the nickel sulfate solution of example 1, the "active-80" magnesium oxide (iodine absorption number 103 mgI) was used₂MgO, bulk density 0.10g/mL, MgO 92.1%), magnesium oxide in a liquid-solid volume ratio of 4: 1, mixing to obtain magnesium oxide slurry.

Slowly pumping the magnesium oxide slurry into a nickel precipitation tank filled with a nickel sulfate solution, adjusting the pH value of the nickel precipitation tank to 7.5, and stably stirring for reaction for 3 hours to obtain the nickel precipitation slurry.

And (3) after the reaction, carrying out filter pressing solid-liquid separation on the nickel precipitation slurry to obtain a nickel precipitation solution and a nickel hydroxide filter cake, and sending the nickel hydroxide filter cake to a drying procedure to obtain the nickel hydroxide product of the comparative example 2.

And (3) carrying out mixed reaction on a composite organic matter LD-1MS with the volume concentration of 20% and a nickel-precipitated solution, wherein the mass ratio of the LD-1MS to (Ni + Co + Mn) is 1.03: 1, filtering after reaction to obtain filter residue and filtrate, and returning the filter residue to high-pressure acid leaching for recycling; and (3) precipitating magnesium from the filtrate by using lime cream, discarding magnesium precipitation slag, and returning the magnesium precipitation liquid to a workshop for recycling.

The detection shows that the nickel deposition rate in the nickel deposition of the active-80 magnesium oxide reaches 99.80 percent, but the cost of the active-80 magnesium oxide is higher. The nickel deposition results and the consumption of auxiliary materials were compared between example 1 and comparative example 2, and the results are shown in table 2.

Table 2 nickel deposition results and auxiliary material consumption costs for example 1 and comparative example 2

As can be seen from the data in Table 2, the nickel precipitation effect of the magnesium oxide of "active-40" is not much different from that of the magnesium oxide of "active-80" by the method of the present application, but the nickel precipitation cost of the magnesium oxide of "active-40" is lower than that of the magnesium oxide of "active-80".

Comparative example 3

The only difference from example 2 is: the liquid after nickel precipitation is not subjected to LD-1MS treatment, lime cream is directly adopted for magnesium precipitation, magnesium precipitation slag is scrapped, and the magnesium precipitation liquid is returned to a workshop for recycling, wherein the comprehensive recovery rate of (Ni + Co + Mn) is 98.31%.

After nickel precipitation, Ni, Co and Mn in the liquid enter the magnesium precipitation slag, the recovery rate is low, and if the magnesium precipitation slag returns to a high-pressure acid leaching system, a large amount of calcium and magnesium impurities are introduced into the system.

Finally, it should be noted that: the above embodiments are only used for illustrating the technical solutions of the present application, and not for limiting the same; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present application.

Moreover, those skilled in the art will appreciate that while some embodiments herein include some features included in other embodiments, rather than other features, combinations of features of different embodiments are meant to be within the scope of the application and form different embodiments. For example, in the claims above, any of the claimed embodiments may be used in any combination. The information disclosed in this background section is only for enhancement of understanding of the general background of the application and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.