MHP precipitation method based on compound alkali precipitant and application of MHP precipitation method

Abstract

The invention provides an MHP precipitation method based on a compound alkali precipitator and application of the MHP precipitation method, and the MHP precipitation method comprises the following steps: mixing laterite-nickel ore iron and aluminum removed liquid and a compound alkali solution for precipitation reaction to obtain cobalt nickel hydroxide slurry; the compound alkali in the compound alkali solution comprises a mixture of sodium carbonate and sodium hydroxide; and carrying out post-treatment on the cobalt nickel hydroxide slurry, and separating to obtain the MHP. According to the method, a sodium hydroxide and sodium carbonate compounded system is used as a precipitator, the MHP is prepared under the cooperation of sodium carbonate and sodium hydroxide, the content of manganese in the obtained MHP is remarkably reduced, the content of nickel and cobalt in the MHP is increased, the method has important significance for reducing the cost for preparing crystals through subsequent MHP refining, meanwhile, the reaction rate is more controllable, the obtained MHP is better in filtering performance, and the method is suitable for industrial production. The water content is lower.

Description

Technical Field

[0001] The invention belongs to the technical field of laterite nickel ore hydrometallurgy and relates to an MHP precipitation method based on a composite alkali precipitant and application thereof. Background Art

[0002] MHP is a mixed nickel-cobalt hydroxide precipitate. As an intermediate product of laterite nickel ore hydrometallurgy, its main metal elements are Ni, Co, Mn and Mg. The content of these metal elements directly determines the quality of MHP, affecting the transportation cost of MHP and the cost of subsequent extraction and refining. In the process of preparing MHP intermediate products by laterite nickel ore hydrometallurgy, sodium hydroxide and magnesium oxide are commonly used precipitants.

[0003] Sodium hydroxide is widely used as a precipitant in the preparation of MHP because it has a wide range of sources, a fast reaction speed when precipitating MHP, and does not introduce additional harmful impurities. It is currently the most common precipitant in industrialization. However, when sodium hydroxide is used to prepare MHP, the precipitation rate of metal ions such as nickel and cobalt is too fast, resulting in a high nucleation rate of MHP, and thus a small particle size of the prepared MHP, which makes it difficult for MHP to be effectively precipitated and filtered, resulting in a high moisture content of the filter cake. In addition, we must note that the manganese content in the MHP currently prepared by sodium hydroxide is relatively high, which significantly increases the cost of subsequent extraction and refining processes, especially the cost of using P204 extractant to extract impurities (calcium, copper, manganese, zinc, etc.) to separate the nickel and cobalt sections. Specifically, compared with other impurities, P204 has a poor separation ability for manganese and nickel and cobalt. Therefore, in the P204 extraction stage, the nickel and cobalt loss rate is high, which greatly increases the alkali consumption, acid consumption, and the amount of extractant used in the preparation of nickel, cobalt, and manganese crystals, as well as the various labor, water, and electricity costs brought about by this.

[0004] The price of magnesium oxide precipitant is relatively low, making it the second largest precipitant in the industry to replace sodium hydroxide for the preparation of MHP. However, magnesium oxide is difficult to dissolve in water, so the prepared MHP has a high magnesium content and a low nickel content, which increases the transportation cost of MHP and the cost of the P507 extraction and magnesium removal stage during subsequent extraction and refining.

[0005] Based on the above research, it is necessary to provide an effective MHP precipitation method, wherein the MHP obtained by the method has a low manganese content and a high nickel and cobalt content, and the MHP is easy to filter and has a low water content. Summary of the invention

[0006] The object of the present invention is to provide an MHP precipitation method based on a composite alkali precipitant and an application thereof. The MHP precipitation method adopts sodium hydroxide and sodium carbonate as precipitants, which can solve the problem that the MHP product obtained by the existing preparation technology has a high manganese content, a low nickel and cobalt content, and a high water content, and greatly reduces the manganese content in MHP and increases the nickel and cobalt content.

[0007] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0008] In a first aspect, the present invention provides a MHP precipitation method based on a composite alkali precipitation agent, the MHP precipitation method comprising the following steps:

[0009] (1) mixing a laterite nickel ore liquid after iron and aluminum removal with a composite alkali solution to perform a precipitation reaction to obtain a nickel-cobalt hydroxide slurry; the composite alkali in the composite alkali solution comprises a mixture of sodium carbonate and sodium hydroxide;

[0010] (2) Post-treating the nickel-cobalt hydroxide slurry described in step (1) to separate and obtain MHP.

[0011] In the prior art, when preparing MHP, sodium hydroxide is used as a precipitant, which easily introduces more manganese into MHP and reduces the content of nickel and cobalt therein. In view of the above defects, the present invention provides an MHP precipitation method based on a composite alkali precipitant, in which a composite system of sodium hydroxide and sodium carbonate is used instead of single sodium hydroxide as a precipitant to prepare MHP, thereby increasing the content of nickel and cobalt in the obtained MHP and reducing the content of other components, especially manganese, which is of great significance for reducing the cost of preparing crystals in the subsequent MHP refining and extraction stage; and the reaction rate is controllable, and the obtained MHP has better filtration performance and low water content.

[0012] In addition, the laterite nickel ore iron and aluminum removal liquid used in the present invention is a liquid phase obtained after the laterite nickel ore is subjected to acid leaching and two-stage iron and aluminum removal. Therefore, the laterite nickel ore iron and aluminum removal liquid is subjected to MHP precipitation, and the impurities such as aluminum impurities and iron impurities are less, which can further increase the nickel and cobalt content in MHP and improve the quality of the MHP product. At the same time, the system pH of the laterite nickel ore iron and aluminum removal liquid is conducive to the precipitation reaction, which can reduce the use of the precipitant.

[0013] In addition, the MHP precipitation method of the present invention can directly produce a product that meets the nickel, cobalt and manganese ratio of the ternary precursor to be prepared through laterite nickel ore.

[0014] Preferably, the laterite nickel ore liquid after iron and aluminum removal in step (1) includes 2-7 g / L of Ni, for example, 2 g / L, 3 g / L, 4 g / L, 5 g / L, 6 g / L or 7 g / L, 0.15-0.8 g / L of Co, for example, 0.15 g / L, 0.25 g / L, 0.35 g / L, 0.45 g / L, 0.55 g / L, 0.65 g / L, 0.75 g / L or 0.8 / L, and 1-5 g / L of Mn, for example, 1 g / L, 2 g / L, 3 g / L, 4 g / L or 5 g / L, but is not limited to the listed values, and other values ​​not listed within the numerical range are equally applicable.

[0015] The laterite nickel ore de-ironized and de-aluminized liquid of the present invention preferably contains a laterite nickel ore de-ironized and de-aluminized liquid solution with a lower nickel and cobalt concentration to prepare MHP, which can increase the nickel and cobalt content of the obtained product.

[0016] Preferably, in the laterite nickel ore liquid after iron and aluminum removal in step (1), the Al content is below 0.03 g / L, for example, it can be 0.03 g / L, 0.02 g / L, 0.01 g / L, 0.008 g / L, 0.006 g / L, 0.004 g / L, 0.002 g / L or 0.001 g / L, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0017] Preferably, in the laterite nickel ore liquid after iron and aluminum removal in step (1), the Fe content is below 0.002 g / L, for example, it can be 0.002 g / L, 0.001 g / L, 0.0008 g / L, 0.0006 g / L, 0.0004 g / L, 0.0002 g / L or 0.0001 g / L, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0018] Preferably, in the laterite nickel ore liquid after iron and aluminum removal in step (1), the Zn content is below 0.03 g / L, for example, it can be 0.03 g / L, 0.02 g / L, 0.01 g / L, 0.008 g / L, 0.006 g / L, 0.004 g / L, 0.002 g / L or 0.001 g / L, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0019] Preferably, in the laterite nickel ore liquid after iron and aluminum removal in step (1), the Ca content is below 0.7 g / L, for example, it can be 0.7 g / L, 0.6 g / L, 0.4 g / L, 0.2 g / L or 0.1 g / L, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0020] The laterite nickel ore liquid after iron and aluminum removal used in the present invention has a low content of impurity ions, which can increase the nickel and cobalt content in MHP and improve its quality.

[0021] Preferably, the precipitation reaction time is 0.5 to 10 h, for example, 1 h, 3 h, 5 h, 7 h, 9 h or 10 h, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable, preferably 0.5-6 h.

[0022] If the precipitation reaction time of the present invention is too short, the obtained MHP particles are small, the filtration performance is poor, and the water content is high. If the reaction time is too long, the manganese in the nickel-cobalt solution will be oxidized, thereby accelerating the hydrolysis of manganese and causing a significant increase in the manganese content in the MHP. In addition, the nickel-cobalt precipitation rate will also decrease, thereby increasing the amount of alkali used.

[0023] Preferably, the precipitation reaction temperature is 55-75°C, for example, 55°C, 60°C, 65°C, 70°C or 75°C, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0024] When the temperature of the precipitation reaction of the present invention is too low, the crystal growth is slow, the obtained MHP particle size is small, the filtration performance is poor, and the water content is high. When the reaction temperature is too high, it is necessary to increase the temperature by introducing steam or the like, which will increase the cost.

[0025] Preferably, the composite alkali comprises 15-95wt% of sodium carbonate, for example, 15wt%, 25wt%, 35wt%, 45wt%, 55wt%, 65wt%, 75wt%, 85wt% or 95wt%, and 5-85wt% of sodium hydroxide, for example, 5wt%, 15wt%, 25wt%, 35wt%, 45wt%, 55wt%, 65wt%, 75wt% or 85wt%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are equally applicable.

[0026] The greater the proportion of sodium carbonate in the composite alkali of the present invention, the lower the manganese content in the obtained MHP, the higher the nickel and cobalt content, and the lower the moisture content of the MHP. However, when the proportion of sodium carbonate in the composite alkali is too large, it is not conducive to the increase of the nickel and cobalt content, and the manganese content will increase.

[0027] Preferably, the content of the composite alkali in the composite alkali solution is 1 to 20 wt%, for example, it can be 1 wt%, 3 wt%, 5 wt%, 7 wt%, 9 wt%, 11 wt%, 13 wt%, 15 wt%, 17 wt%, 19 wt% or 20 wt%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0028] The mass fraction of the composite alkali solution of the present invention is not easy to be too high, which is easy to form local over-alkali; when the proportion of sodium carbonate in the composite alkali solution increases, the concentration of the composite alkali solution can be appropriately increased. The mass fraction of the composite alkali solution is also not easy to be too low, and the nickel-cobalt solution will be seriously diluted, which will not only increase the amount of alkali used in the MHP precipitation process, but also reduce production efficiency.

[0029] Preferably, the ratio of the total molar amount of the composite alkali to the total molar amount of nickel and cobalt in the laterite nickel ore after iron and aluminum removal is 1.4 to 2.5, for example, it can be 1.4, 1.6, 1.8, 2.0, 2.2, 2.4 or 2.5, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0030] When the molar ratio of the present invention is too low, although the MHP quality is high, the nickel-cobalt precipitation rate is low, resulting in a significant decrease in equipment utilization and product production efficiency. When the molar ratio is too high, the MHP quality will be reduced.

[0031] Preferably, the composite alkali solution is obtained by adding composite alkali into water or industrial water and mixing.

[0032] Preferably, the post-processing includes thickening and solid-liquid separation performed sequentially.

[0033] Preferably, part of the underflow material after the thickening treatment is reused in the precipitation reaction as seed crystals.

[0034] In the present invention, part of the concentrated underflow is returned to the MHP precipitation reaction system as a crystal seed to promote the growth of MHP crystals and thus improve the filtering performance of MHP.

[0035] Preferably, the solid-liquid separation comprises vacuum filtration or filter press filtration.

[0036] Preferably, during the solid-liquid separation, the MHP filter cake is washed with distilled water or industrial water.

[0037] The present invention adopts distilled water or industrial water to wash the MHP filter cake, which can remove soluble impurity components such as sulfate and improve the purity of MHP.

[0038] The present invention adopts distilled water or industrial water to wash the MHP filter cake, which can remove soluble impurity components such as sulfate and improve the purity of MHP.

[0039] In a second aspect, the present invention provides an MHP, wherein the MHP is obtained by precipitation using the MHP precipitation method as described in the first aspect.

[0040] Preferably, in the MHP, the Ni content is 40-43wt%, for example, 40wt%, 40.5wt%, 41wt%, 41.5wt%, 42wt%, 42.5wt% or 43wt%, and the Co content is 3.2-4.3wt%, for example, 3.2wt%, 3.3wt%, 3.4wt%, 3.5wt%, 3.6wt%, 3.7wt%, 3.8wt%, 3.9wt%, 4.0wt%, 4.1 wt%, 4.2wt% or 4.3wt%, the Mn content is 2.5-6.5wt%, for example, it can be 2.5wt%, 3.5wt%, 4.5wt%, 5.5wt% or 6.5wt%, the Mg content is 0.4-1.5wt%, for example, it can be 0.4wt%, 0.6wt%, 0.8wt%, 1.0wt%, 1.2wt% or 1.5wt%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are equally applicable.

[0041] In the MHP prepared by the preparation method of the present invention, the Mn content can be reduced to less than 3wt%, and the nickel and cobalt contents can be increased to more than 42wt% and 4wt%, respectively, indicating that the use of a composite system of sodium hydroxide and sodium carbonate as a precipitant can greatly reduce the manganese content and increase the nickel and cobalt contents, and can significantly reduce the cost of subsequent MHP refining and preparing crystals, while making the reaction rate more controllable, and the obtained MHP has better filtration performance and lower water content.

[0042] The application of the MHP of the present invention includes the application for preparing ternary precursor materials.

[0043] Compared with the prior art, the present invention has the following beneficial effects:

[0044] The invention uses a sodium hydroxide and sodium carbonate compound system as a precipitant to prepare MHP, wherein sodium carbonate is used as a strong electrolyte and a strong base and weak acid salt. The MHP is prepared under the coordination of sodium carbonate and sodium hydroxide, which significantly reduces the content of Mn in the obtained MHP and increases the content of nickel and cobalt therein, and is of great significance for reducing the cost of subsequent MHP extraction and refining to prepare crystals; and the reaction rate is controllable, the obtained MHP has better filterability, and the water content is lower than 50%. DETAILED DESCRIPTION

[0045] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0046] The laterite nickel ore iron-aluminum-removed liquid used in the following examples and comparative examples is a liquid phase obtained after the laterite nickel ore is subjected to acid leaching and two-stage iron-aluminum-removal. The main components of the laterite nickel ore iron-aluminum-removed liquid are shown in Table 1 below:

[0047] Table 1

[0048]

[0049] Example 1

[0050] This embodiment provides a MHP precipitation method based on a composite alkali precipitation agent, which specifically includes the following steps:

[0051] (1) preparing a composite alkali solution: adding 38.37 g of a composite alkali as a precipitant into industrial water and stirring for 10 min to obtain a composite alkali solution, wherein the mass fraction of the composite alkali solution is 10%, and the composite alkali comprises 10 wt % of sodium carbonate and 90 wt % of sodium hydroxide;

[0052] (2) Precipitating MHP: Add the prepared composite alkali solution to 10 L of laterite nickel ore after iron and aluminum removal to react at a temperature of 60° C. for 2 h to obtain MHP slurry;

[0053] (3) Thickening: The MHP slurry is thickened to obtain a thickened supernatant and an MHP underflow;

[0054] (4) Filtration: Filter the MHP underflow and wash the MHP filter cake with industrial water.

[0055] Example 2

[0056] This embodiment provides a MHP precipitation method based on a composite alkali precipitation agent. The MHP precipitation method is the same as that of Embodiment 1 except that the composite alkali is 15 wt % sodium carbonate and 85 wt % sodium hydroxide.

[0057] Example 3

[0058] This embodiment provides a MHP precipitation method based on a composite alkali precipitation agent. The MHP precipitation method is the same as that of Embodiment 1 except that the composite alkali is 20 wt % sodium carbonate and 80 wt % sodium hydroxide.

[0059] Example 4

[0060] This embodiment provides a MHP precipitation method based on a composite alkali precipitation agent. The MHP precipitation method is the same as that of Embodiment 1 except that the composite alkali is 35 wt % sodium carbonate and 65 wt % sodium hydroxide.

[0061] Example 5

[0062] This embodiment provides a MHP precipitation method based on a composite alkali precipitation agent. The MHP precipitation method is the same as that of Embodiment 1 except that the composite alkali is 60 wt % of sodium carbonate and 40 wt % of sodium hydroxide.

[0063] Example 6

[0064] This embodiment provides a MHP precipitation method based on a composite alkali precipitation agent. The MHP precipitation method is the same as that of Embodiment 1 except that the composite alkali is 85 wt % sodium carbonate and 15 wt % sodium hydroxide.

[0065] Comparative Example 1

[0066] This comparative example provides an MHP precipitation method, which is the same as Example 1 except that the mass of sodium carbonate in the composite alkali is replaced by sodium hydroxide and pure sodium hydroxide is used as the precipitant.

[0067] Comparative Example 2

[0068] This comparative example provides an MHP precipitation method, which is the same as Example 1 except that the mass of sodium hydroxide in the composite alkali is replaced by sodium carbonate and pure sodium carbonate is used as the precipitant.

[0069] Comparative Example 3

[0070] This comparative example provides an MHP precipitation method, which is the same as Example 1 except that the sodium hydroxide in the composite alkali is replaced by sodium carbonate with 1.5 times its mass and pure sodium carbonate is used as the precipitant.

[0071] The MHP components obtained in the above embodiments and comparative examples were tested by ICP method. The results are shown in Table 2 below. Table 2 also includes the content of sodium carbonate in the precipitant. At the same time, the MHP filter cakes obtained in each embodiment and comparative example were dried to test their moisture content.

[0072] Table 2

[0073]

[0074]

[0075] From the above table we can see that:

[0076] (1) Compared with Example 1, the Mn content of Example 1 is 6.02wt%. The addition of sodium carbonate has an important influence on the precipitation rate of nickel, cobalt and manganese and the composition of MHP. Within a certain range, as the mass fraction of sodium carbonate in the compound alkali increases (10%-85wt%), the nickel content and cobalt content in the prepared MHP continue to increase, the manganese content continues to decrease, and the magnesium content does not change much. In addition, the method of the present invention uses the compound alkali as a precipitant to prepare high-quality MHP, and the moisture content of the MHP filter cake can be optimized to about 46%, which shows that the MHP particles prepared by the present invention have good filtration performance and are conducive to reducing the moisture content.

[0077] (2) It can be seen from Example 6 and Comparative Examples 2-3 that sodium carbonate is used in all of Comparative Example 2, and when the amount of sodium carbonate is increased to 1.5 times the theoretical amount of sodium hydroxide used to precipitate MHP, the manganese content in MHP increases rapidly to 9.21%, which causes the nickel content in the precipitate to drop rapidly to 31.17%, and the cobalt content also decreases accordingly. Obviously, the manganese and magnesium contents in the MHP prepared using sodium carbonate alone as a precipitant are significantly increased, and the nickel and cobalt contents are obviously lower. Therefore, the quality of MHP prepared using only sodium carbonate as a precipitant is significantly worse than that prepared using a composite system of sodium hydroxide and sodium carbonate as a precipitant.

[0078] In summary, the present invention provides an MHP precipitation method based on a composite alkali precipitant and an application thereof. The MHP precipitation method can significantly reduce the manganese content in MHP and increase the nickel and cobalt contents by using sodium hydroxide and sodium carbonate as precipitants, which is of great significance for reducing the cost of subsequent MHP refining and preparing crystals. At the same time, the reaction rate is more controllable, and the obtained MHP has better filtration performance and lower water content.

[0079] The above description is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention are within the protection scope and disclosure scope of the present invention.

Claims

1. A MHP precipitation method based on a composite alkali precipitant, characterized in that: The MHP precipitation method comprises the following steps: (1) mixing a laterite nickel ore liquid after iron and aluminum removal with a composite alkali solution to perform a precipitation reaction to obtain a nickel-cobalt hydroxide slurry; the composite alkali in the composite alkali solution comprises a mixture of sodium carbonate and sodium hydroxide; (2) Post-treating the nickel-cobalt hydroxide slurry described in step (1) to separate and obtain MHP.

2. The MHP precipitation method according to claim 1, characterized in that: The laterite nickel ore liquid after iron and aluminum removal in step (1) comprises 2-7 g / L Ni, 0.15-0.8 g / L Co, and 1-5 g / L Mn.

3. The MHP precipitation method according to claim 1 or 2, characterized in that: In the laterite nickel ore liquid after iron and aluminum removal in step (1), the Al content is below 0.03 g / L; Preferably, in the laterite nickel ore liquid after iron and aluminum removal in step (1), the Fe content is less than 0.002 g / L; Preferably, the Zn content in the laterite nickel ore liquid after iron and aluminum removal in step (1) is less than 0.03 g / L; Preferably, in the laterite nickel ore liquid after iron and aluminum removal in step (1), the Ca content is below 0.7 g / L.

4. The MHP precipitation method according to any one of claims 1 to 3, characterized in that: The precipitation reaction time in step (1) is 0.5 to 10 hours, preferably 0.5 to 6 hours; Preferably, the temperature of the precipitation reaction in step (1) is 55-75°C.

5. The MHP precipitation method according to any one of claims 1 to 4, characterized in that: The composite alkali in step (1) comprises 15-95wt% of sodium carbonate and 5-85wt% of sodium hydroxide; Preferably, the content of the composite alkali in the composite alkali solution in step (1) is 1 to 20 wt%.

6. The MHP precipitation method according to any one of claims 1 to 5, characterized in that: The ratio of the total molar amount of the composite alkali in step (1) to the total molar amount of nickel and cobalt in the laterite nickel ore after iron and aluminum removal is 1.4 to 2.5; Preferably, the composite alkali solution in step (1) is obtained by adding composite alkali into water or industrial water and mixing.

7. The MHP precipitation method according to any one of claims 1 to 6, characterized in that: The post-treatment in step (2) includes sequential thickening and solid-liquid separation.

8. The MHP precipitation method according to claim 7, characterized in that: Part of the underflow material after the thickening treatment is reused in the precipitation reaction as seed crystals; Preferably, the solid-liquid separation comprises vacuum filtration or filter press filtration; Preferably, during the solid-liquid separation, the MHP filter cake is washed with distilled water or industrial water.

9. An MHP, characterized in that The MHP is obtained by precipitation using the MHP precipitation method according to any one of claims 1 to 8.

10. The MHP according to claim 9, characterized in that In the MHP, the Ni content is 40-43wt%, the Co content is 3.2-4.3wt%, the Mn content is 2.5-6.0wt%, and the Mg content is 0.4-1.5wt%.

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