Method for activating and precipitating MHP through magnesium

Abstract

The invention discloses a method for activating and precipitating MHP through magnesium, and belongs to the technical field of hydrometallurgy. The method comprises the following steps: S1, mixing a magnesium-containing solution with a sodium hydroxide solution, and carrying out precipitation reaction for 3-5 minutes to obtain a precipitator; s2, immediately mixing a precipitator with the laterite-nickel ore iron and aluminum removed liquid, and then carrying out first-stage nickel and cobalt precipitation reaction to obtain first-stage nickel and cobalt precipitation slurry; s3, performing first thickening treatment on the first-section nickel and cobalt deposited slurry to obtain first dense underflow and first dense overflow; and S4, filtering the first dense underflow to obtain an MHP product. According to the method, after the magnesium-containing solution and the sodium hydroxide solution are mixed, the magnesium solution and the sodium hydroxide solution are controlled to be mixed and react for 3-5 min, then the nickel and cobalt precipitation reaction is immediately carried out, the MHP product with high purity and quality can be obtained, and the whole method is simple and convenient for large-scale industrial application.

Description

Technical Field

[0001] The present application belongs to the technical field of hydrometallurgy, and specifically relates to a method for magnesium activated precipitation of MHP. Background Art

[0002] MHP (nickel cobalt hydroxide) is an intermediate product of laterite nickel ore hydrometallurgy. It can be used to make nickel sulfate, refined nickel cobalt hydroxide, nickel plates and other products, and has good application prospects.

[0003] At present, in the hydrometallurgical process of laterite nickel ore, a one-stage nickel-cobalt precipitation process is mostly used to prepare MHP products. However, the existing technology mostly uses sodium hydroxide solution as a precipitant for nickel-cobalt precipitation treatment, and the problem of local over-alkalinity will occur during the addition of the precipitant; and local over-alkalinity will cause the pH value in the local aqueous solution to be too high, thereby causing multiple metal ions (mainly including nickel ions, cobalt ions, magnesium ions and manganese ions) to precipitate simultaneously, which makes the precipitated product contain more impurity ions, resulting in poor quality of the prepared MHP product.

[0004] Therefore, it is urgent to propose a new processing method to solve the above problems existing in the prior art. Summary of the invention

[0005] The purpose of this application is to provide a method for magnesium activated precipitation of MHP, aiming to solve the problems of local over-alkalinity in the existing one-stage nickel-cobalt precipitation process for preparing MHP products, which leads to high impurity content and poor quality of MHP products.

[0006] In a first aspect, the present application provides a method for magnesium-activated precipitation of MHP, comprising the following steps: S1, mixing a magnesium-containing solution with a sodium hydroxide solution, and subjecting the mixture to a precipitation reaction for 3 to 5 minutes to obtain a precipitant; S2, immediately mixing the precipitant with a laterite nickel ore solution after iron and aluminum removal, and subjecting the solution to a nickel-cobalt precipitation reaction to obtain a nickel-cobalt precipitation slurry; S3, subjecting the nickel-cobalt precipitation slurry to a first thickening treatment to obtain a first thickened underflow and a first thickened overflow; S4, filtering the first thickened underflow to obtain an MHP product.

[0007] In the present application, the inventors have found that mixing a magnesium-containing solution with a sodium hydroxide solution can reduce the alkalinity of the solution, thereby solving the problem of local over-alkalinity when directly using a sodium hydroxide solution to precipitate nickel and cobalt to prepare an MHP product. Therefore, the method of the present application can improve the purity and quality of the MHP product.

[0008] And the inventor further found that the time of the mixed reaction of magnesium solution and sodium hydroxide solution has an important influence on the quality of MHP products. If the reaction time is too short, the alkalinity of the mixed solution will not change significantly, and there will still be a problem of local over-alkali in the subsequent nickel-cobalt precipitation reaction; if the reaction time is too long, the magnesium hydroxide precipitate formed will agglomerate, crystallize and grow, forming crystals with too large particle size. When a nickel-cobalt precipitation reaction is carried out, the magnesium hydroxide crystals are difficult to be quickly dissolved, so they are easily wrapped by the nickel-cobalt hydroxide crystals formed during the nickel-cobalt precipitation process, so that the impurity content of the MHP product is increased. Therefore, after the magnesium solution and the sodium hydroxide solution are mixed and reacted for 3 to 5 minutes, a nickel-cobalt precipitation reaction is immediately carried out. Since the reaction time of magnesium and sodium hydroxide is slow, the crystals formed are small. In the process of a nickel-cobalt precipitation reaction, they are quickly dissolved by the laterite nickel ore after iron and aluminum removal, so that they will not be coated in the nickel-cobalt hydroxide precipitation, so that a better quality MHP product can be obtained.

[0009] In some embodiments, in step S1, the concentration of magnesium ions in the magnesium-containing solution is 4 to 6 g / L, for example, 4 g / L, 4.5 g / L, 5 g / L, 5.5 g / L, 6 g / L or other values ​​within the range; the mass fraction of the sodium hydroxide solution is 10 to 13%, for example, 10%, 11%, 12%, 13% or other values ​​within the range; the volume ratio of the magnesium-containing solution to the sodium hydroxide solution is (8 to 15):100, for example, 8:100, 9:100, 10:100, 11:10 The precipitation reaction further comprises: carrying out the precipitation reaction at a temperature of 50-65°C (for example, 50°C, 55°C, 60°C, 65°C or other values ​​within the range), a stirring speed of 1-2r / min (for example, 1r / min, 1.2r / min, 1.4r / min, 1.6r / min, 1.5r / min, 2r / min or other values ​​within the range) and a pressure of normal pressure.

[0010] In some embodiments, in step S2, the laterite nickel ore liquid after iron and aluminum removal includes the following components: 2-6 g / L nickel, 0.1-0.5 g / L cobalt, 2-3 g / L manganese, and 4-10 g / L magnesium.

[0011] In the laterite nickel ore liquid after iron and aluminum removal provided in the present application, nickel can be, for example, 2g / L, 3g / L, 4g / L, 5g / L, 6g / L or other values ​​within this range, cobalt can be, for example, 0.1g / L, 0.2g / L, 0.3g / L, 0.4g / L, 0.5g / L or other values ​​within this range, manganese can be, for example, 2g / L, 2.2g / L, 2.4g / L, 2.6g / L, 2.8g / L, 3g / L or other values ​​within this range, and magnesium can be, for example, 4g / L, 6g / L, 8g / L, 10g / L or other values ​​within this range.

[0012] In some embodiments, in step S2, the pH value of the nickel-cobalt precipitation reaction is 6.8-7.2, for example, it can be 6.8, 6.9, 7, 7.1, 7.2 or other values ​​within this range; the time is 4-6h, for example, it can be 4h, 4.5h, 5h, 5.5h, 6h or other values ​​within this range.

[0013] In some embodiments, step S3 further includes the steps of performing a second-stage nickel-cobalt precipitation reaction on the first concentrated overflow to obtain a second-stage nickel-cobalt precipitation slurry, and then performing a second thickening treatment on the second-stage nickel-cobalt precipitation slurry to obtain a second concentrated overflow, and continuing to perform a manganese precipitation treatment on the second concentrated overflow to obtain a laterite nickel ore liquid after manganese removal; wherein the laterite nickel ore liquid after manganese removal is reused as a magnesium-containing solution.

[0014] In the present application, the liquid after manganese removal from laterite nickel ore is reused as a magnesium-containing solution to improve the utilization rate of raw materials.

[0015] In some embodiments, the magnesium ion concentration in the laterite nickel ore liquid after manganese removal is 4-6 g / L, for example, it can be 4 g / L, 4.5 g / L, 5 g / L, 5.5 g / L, 6 g / L or other values ​​within this range.

[0016] In some embodiments, the pH value of the second-stage nickel-cobalt precipitation reaction is 7.8-8.2, for example, it can be 7.8, 7.9, 8, 8.2 or other values ​​within the range.

[0017] In some embodiments, the pH value of the manganese precipitation treatment is 10.0-10.5, for example, it can be 10.0, 10.1, 10.2, 10.3, 10.4, 10.5 or other values ​​within the range.

[0018] In some embodiments, step S3 further includes recycling a portion of the first concentrated underflow to a first nickel-cobalt precipitation reaction step.

[0019] In some preferred embodiments, the portion of the first thick underflow that is recycled accounts for 4 / 5 to 9.5 / 10 of the total amount of the first thick underflow.

[0020] In the present invention, by recycling part of the first dense underflow as a crystal seed to the first nickel-cobalt precipitation reaction step, better crystallization of nickel-cobalt hydroxide can be promoted.

[0021] In some embodiments, in step S4, the filtration treatment includes vacuum filtration or filter press filtration, and the filter cake is washed with distilled water during filtration.

[0022] The beneficial effects of the present application are as follows: different from the prior art, the present application can reduce the alkalinity of the solution by mixing the magnesium-containing solution with the sodium hydroxide solution, thereby solving the problem of local over-alkalinity generated when the sodium hydroxide solution is directly used to carry out a one-stage nickel-cobalt precipitation to prepare the MHP product; further, after controlling the magnesium solution and the sodium hydroxide solution to mix and react for 3 to 5 minutes, a one-stage nickel-cobalt precipitation reaction is immediately carried out, so that an MHP product with higher purity and quality can be obtained, and the whole method is simple and convenient for large-scale industrial application. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 The flowchart of the method for magnesium-activated precipitation of MHP in this application is shown in FIG. DETAILED DESCRIPTION

[0024] The following will be combined with the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0025] The experimental methods without specific conditions in the examples are usually carried out according to conventional conditions and conditions described in the manual, or according to conditions recommended by the manufacturer. The general equipment, materials, reagents, etc. used are all available from commercial channels unless otherwise specified.

[0026] See also Figure 1 , which is a method flow chart in the present application. Specifically, the method comprises the following steps: mixing a magnesium-containing solution with a sodium hydroxide solution, and subjecting the mixture to a precipitation reaction to obtain a precipitant; mixing the precipitant with a laterite nickel ore solution after iron and aluminum removal, and subjecting the solution to a first nickel-cobalt precipitation reaction to obtain a first nickel-cobalt precipitation slurry; subjecting the first nickel-cobalt precipitation slurry to a first thickening treatment to obtain a first thickened underflow and a first thickened overflow, wherein the first thickened overflow is subjected to a second nickel-cobalt precipitation reaction to obtain a second nickel-cobalt precipitation slurry, and then subjecting the second nickel-cobalt precipitation slurry to a second thickening treatment to obtain a second thickened overflow, and further subjecting the second thickened overflow to a manganese precipitation treatment to obtain a laterite nickel ore solution after manganese removal, and reusing the laterite nickel ore solution after manganese removal as a magnesium-containing solution; reusing part of the first thickened underflow to the first nickel-cobalt precipitation reaction step; filtering the remaining first thickened underflow to obtain an MHP product.

[0027] The laterite nickel ore de-ironized and de-aluminized liquid used in the examples and comparative examples is the liquid phase obtained after acid leaching and two-stage de-ironization and de-aluminization of the laterite nickel ore, which mainly includes the following components: 3.87 g / L nickel, 0.41 g / L cobalt, 2.73 g / L manganese, and 6.44 g / L magnesium.

[0028] Example 1

[0029] A method for magnesium activated precipitation of MHP comprises the following steps:

[0030] S1. Mixing the liquid after manganese removal from laterite nickel ore with a sodium hydroxide solution having a mass fraction of 12% in a volume ratio of 11:100, and subjecting the mixture to a precipitation reaction for 4 minutes at a temperature of 55° C., a stirring speed of 1.5 r / min, and a pressure of normal pressure to obtain a precipitant;

[0031] S2, immediately mixing the precipitant obtained in step S1 with the laterite nickel ore after iron and aluminum removal, and carrying out a nickel-cobalt precipitation reaction for 5 hours at a pH value of 7 to obtain a nickel-cobalt precipitation slurry;

[0032] S3, performing a first thickening treatment on the first stage nickel-cobalt precipitation slurry obtained in step S2 to obtain a first thickened underflow and a first thickened overflow, wherein the first thickened overflow is subjected to a second stage nickel-cobalt precipitation reaction (pH value is 8.0) to obtain a second stage nickel-cobalt precipitation slurry, and then the second stage nickel-cobalt precipitation slurry is subjected to a second thickening treatment to obtain a second thickened overflow, and the second thickened overflow is further subjected to a manganese precipitation treatment (pH value is 10.3) to obtain a laterite nickel ore manganese-free liquid, and the laterite nickel ore manganese-free liquid is reused in step S1; 9 / 10 of the first thickened underflow is reused in step S2;

[0033] S4. Filter the remaining 1 / 10 of the first dense underflow by vacuum filtration, and wash the filter cake with distilled water during filtration to obtain an MHP product.

[0034] Example 2

[0035] A method for magnesium activated precipitation of MHP comprises the following steps:

[0036] S1, mixing the liquid after manganese removal from laterite nickel ore with a sodium hydroxide solution having a mass fraction of 13% in a volume ratio of 15:100, and performing a precipitation reaction for 3 minutes at a temperature of 50° C., a stirring speed of 2 r / min, and a pressure of normal pressure to obtain a precipitant;

[0037] S2, immediately mixing the precipitant obtained in step S1 with the laterite nickel ore liquid after iron and aluminum removal, and carrying out a nickel-cobalt precipitation reaction for 6 hours at a pH value of 7.2 to obtain a nickel-cobalt precipitation slurry;

[0038] S3, performing a first thickening treatment on the first stage nickel-cobalt precipitation slurry obtained in step S2 to obtain a first thickened underflow and a first thickened overflow, wherein the first thickened overflow is subjected to a second stage nickel-cobalt precipitation reaction (pH value is 8.2) to obtain a second stage nickel-cobalt precipitation slurry, and then the second stage nickel-cobalt precipitation slurry is subjected to a second thickening treatment to obtain a second thickened overflow, and the second thickened overflow is further subjected to a manganese precipitation treatment (pH value is 10.5) to obtain a laterite nickel ore manganese-free liquid, and the laterite nickel ore manganese-free liquid is reused in step S1; 9 / 10 of the first thickened underflow is reused in step S2;

[0039] S4. Filter the remaining 1 / 10 of the first dense underflow by vacuum filtration, and wash the filter cake with distilled water during filtration to obtain an MHP product.

[0040] Example 3

[0041] A method for magnesium activated precipitation of MHP comprises the following steps:

[0042] S1, mixing the liquid after manganese removal from laterite nickel ore with a sodium hydroxide solution having a mass fraction of 10% in a volume ratio of 10:100, and performing a precipitation reaction for 5 minutes at a temperature of 65° C., a stirring speed of 1 r / min, and a pressure of normal pressure to obtain a precipitant;

[0043] S2, immediately mixing the precipitant obtained in step S1 with the laterite nickel ore liquid after iron and aluminum removal, and carrying out a nickel-cobalt precipitation reaction for 4 hours at a pH value of 6.8 to obtain a nickel-cobalt precipitation slurry;

[0044] S3, performing a first thickening treatment on the first stage nickel-cobalt precipitation slurry obtained in step S2 to obtain a first thickened underflow and a first thickened overflow, wherein the first thickened overflow is subjected to a second stage nickel-cobalt precipitation reaction (pH value is 7.8) to obtain a second stage nickel-cobalt precipitation slurry, and then the second stage nickel-cobalt precipitation slurry is subjected to a second thickening treatment to obtain a second thickened overflow, and the second thickened overflow is further subjected to a manganese precipitation treatment (pH value is 10.0) to obtain a laterite nickel ore manganese-free liquid, and the laterite nickel ore manganese-free liquid is reused in step S1; 9 / 10 of the first thickened underflow is reused in step S2;

[0045] S4. Filter the remaining 1 / 10 of the first dense underflow by vacuum filtration, and wash the filter cake with distilled water during filtration to obtain an MHP product.

[0046] Comparative Example 1

[0047] The method of magnesium-activated precipitation of MHP in this comparative example is basically the same as that in Example 1, except that in step S1, the precipitation reaction is performed for 1 min.

[0048] Comparative Example 2

[0049] The method of magnesium-activated precipitation of MHP in this comparative example is basically the same as that in Example 1, except that in step S1, the precipitation reaction lasts for 7 minutes.

[0050] Performance Testing

[0051] The nickel content, magnesium content and moisture content of the MHP products prepared in Examples 1 to 3 and Comparative Examples 1 to 2 were tested, and the results are shown in Table 1.

[0052] Table 1 Nickel content, magnesium content and moisture content of MHP products

[0053] Ni content (%) Mg content (%) Moisture content (%) Example 1 41.12 1.62 48.46 Example 2 41.29 2.08 49.29 Example 3 41.4 1.99 49.65 Comparative Example 1 39.85 2.78 57.6 Comparative Example 2 39.55 2.61 62.37

[0054] It can be seen from the data in Table 1 that the MHP products prepared by the methods in Examples 1-3 of the present application have better quality (higher nickel content, lower magnesium content and lower water content); while in Comparative Examples 1 and 2, the precipitation reaction time is shorter or longer, and it is found that the quality of the prepared MHP product has decreased to a certain extent (decreased nickel content, increased magnesium content and increased water content). The results show that in the present application, by controlling the time of the mixed reaction of the magnesium solution and the sodium hydroxide solution within a specific range, a better quality MHP product can be prepared.

[0055] In summary, in the present application, by controlling the mixing reaction of the magnesium solution and the sodium hydroxide solution for 3 to 5 minutes, and then immediately carrying out a nickel-cobalt precipitation reaction, a MHP product with higher purity and quality can be obtained.

[0056] It should be noted that the above embodiments all belong to the same inventive concept, and the description of each embodiment has its own focus. For matters that are not described in detail in some embodiments, reference may be made to the description in other embodiments.

[0057] The above-mentioned embodiments only express the implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the attached claims.

Claims

1. A method for magnesium activated precipitation of MHP, characterized in that: The steps include: S1. Mixing the magnesium-containing solution with the sodium hydroxide solution and subjecting the mixture to precipitation reaction for 3 to 5 minutes to obtain a precipitant; S2, immediately mixing the precipitant with the laterite nickel ore after iron and aluminum removal, and then performing a nickel-cobalt precipitation reaction to obtain a nickel-cobalt precipitation slurry; S3, performing a first thickening treatment on the first stage nickel-cobalt precipitation slurry to obtain a first thickened underflow and a first thickened overflow; S4. Filter the first dense underflow to obtain an MHP product.

2. The method for magnesium activated precipitation of MHP according to claim 1, characterized in that: In step S1, the concentration of magnesium ions in the magnesium-containing solution is 4-6 g / L; the mass fraction of the sodium hydroxide solution is 10-13%; the volume ratio of the magnesium-containing solution to the sodium hydroxide solution is (8-15):100; The precipitation reaction further comprises: performing the precipitation reaction at a temperature of 50-65° C., a stirring speed of 1-2 r / min, and a pressure of normal pressure.

3. The method for magnesium activated precipitation of MHP according to claim 1, characterized in that: In step S2, the laterite nickel ore liquid after iron and aluminum removal includes the following components: Nickel 2-6g / L, cobalt 0.1-0.5g / L, manganese 2-3g / L, magnesium 4-10g / L.

4. The method for magnesium activated precipitation of MHP according to claim 1, characterized in that: In step S2, the pH value of the nickel-cobalt precipitation reaction is 6.8-7.2, and the time is 4-6 hours.

5. The method for magnesium activated precipitation of MHP according to claim 1, characterized in that: Step S3 further includes the steps of performing a second-stage nickel-cobalt precipitation reaction on the first concentrated overflow to obtain a second-stage nickel-cobalt precipitation slurry, further performing a second thickening treatment on the second-stage nickel-cobalt precipitation slurry to obtain a second concentrated overflow, and continuing to perform a manganese precipitation treatment on the second concentrated overflow to obtain a laterite nickel ore liquid after manganese removal; Wherein, the liquid after manganese removal from the laterite nickel ore is reused as a magnesium-containing solution.

6. The method for magnesium activated precipitation of MHP according to claim 5, characterized in that: The magnesium ion concentration in the laterite nickel ore liquid after manganese removal is 4-6 g / L.

7. The method for magnesium activated precipitation of MHP according to claim 5, characterized in that: The pH value of the second-stage nickel-cobalt precipitation reaction is 7.8-8.

2.

8. The method for magnesium activated precipitation of MHP according to claim 5, characterized in that: The pH value of the manganese precipitation treatment is 10.0-10.

5.

9. The method for magnesium activated precipitation of MHP according to claim 1, characterized in that: Step S3 also includes recycling part of the first concentrated underflow to the first stage nickel-cobalt precipitation reaction step.

10. The method for magnesium activated precipitation of MHP according to claim 1, characterized in that: In step S4, the filtration treatment includes using vacuum filtration or filter press filtration, and washing the filter cake with distilled water during filtration.

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