MHP precipitation method based on complex alkali precipitants and application thereof

Abstract

The application provides a MHP precipitation method based on a compounded alkali precipitant and application thereof, and the MHP precipitation method comprises the following steps: mixing a laterite nickel ore iron and aluminum removal liquid and a compounded alkali solution to carry out a precipitation reaction, and obtaining a nickel cobalt hydroxide slurry; the compounded alkali in the compounded alkali solution comprises a mixture of sodium carbonate and sodium hydroxide; and the nickel cobalt hydroxide slurry is subjected to post-treatment, and MHP is separated and obtained. In the application, a sodium hydroxide and sodium carbonate compounded system is used as a precipitant, and MHP is prepared under the cooperation of sodium carbonate and sodium hydroxide, so that the content of manganese in the obtained MHP is significantly reduced, and the content of nickel and cobalt is increased, which is of great significance for reducing the cost of subsequent MHP refining and preparation of crystals, and at the same time, the reaction rate is more controllable, the filtration performance of the obtained MHP is better, and the water content is lower.

Description

TECHNICAL FIELD

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

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

[0003] Sodium hydroxide is widely used as a precipitant in the preparation of MHP, because it is widely available, has a fast reaction speed when precipitating MHP and does not introduce additional harmful impurities, and is the most common precipitant in the current industry. However, when sodium hydroxide is used to prepare MHP, the precipitation rate of metal ions such as nickel and cobalt is too fast, which leads to a high nucleation rate of MHP, and thus the prepared MHP has a small particle size, which makes it difficult to effectively settle and filter, resulting in a high moisture content of the filter cake. In addition, we must note that the content of manganese in the MHP prepared by sodium hydroxide is relatively high, which significantly increases the cost of the subsequent extraction and refining process, especially the cost of separating nickel and cobalt using P204 extractant to remove impurities (calcium, copper, manganese, zinc, etc.). Specifically, compared with other impurities, P204 has poor separation ability for manganese and nickel-cobalt, so the loss rate of nickel and cobalt is high in the P204 impurity removal stage, which greatly increases the alkali consumption, acid consumption, amount of extractant and various costs such as labor, water and electricity in the preparation process of nickel, cobalt and manganese crystals.

[0004] Magnesium oxide precipitant has a relatively low price, and has become the second largest precipitant for preparing MHP in the industry instead of sodium hydroxide. 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 in the subsequent extraction and refining process.

[0005] Based on the above research, it is necessary to provide an effective MHP precipitation method, which has a low manganese content and a high nickel-cobalt content, and the MHP is easy to filter and has a low moisture content. SUMMARY

[0006] The purpose of the present application is to provide an MHP precipitation method based on a compound alkali precipitant and application thereof, which can solve the problems of high manganese content, low nickel-cobalt content and high moisture content of the MHP product prepared by the existing preparation technology, greatly reduce the manganese content of MHP and increase the nickel-cobalt content by using sodium hydroxide and sodium carbonate as precipitants.

[0007] To achieve the object of the present application, the following technical solutions are adopted:

[0008] In a first aspect, the present application provides a MHP precipitation method based on a compounded alkali precipitant, which comprises the following steps:

[0009] (1) mixing a red soil nickel ore iron and aluminum removal solution and a compounded alkali solution to perform a precipitation reaction, to obtain a nickel-cobalt hydroxide slurry; the compounded alkali in the compounded alkali solution comprises a mixture of sodium carbonate and sodium hydroxide;

[0010] (2) performing post-treatment on the nickel-cobalt hydroxide slurry of step (1) to separate and obtain MHP.

[0011] In the prior art, when MHP is prepared, sodium hydroxide is used as a precipitant, which can easily introduce a large amount of manganese into MHP, thereby reducing the content of nickel and cobalt therein. In view of the above defects, the present application provides a MHP precipitation method based on a compounded alkali precipitant, which uses a sodium hydroxide and sodium carbonate compounded system to replace 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 section. Moreover, the reaction rate is controllable, the obtained MHP has better filtration performance, and the water content is low.

[0012] Furthermore, the red soil nickel ore iron and aluminum removal solution is a liquid phase obtained after red soil nickel ore is subjected to acid leaching and two-stage iron and aluminum removal, and therefore, the red soil nickel ore iron and aluminum removal solution has a low content of impurities such as aluminum impurities and iron impurities, which can further increase the content of nickel and cobalt in MHP and improve the quality of MHP products. Meanwhile, the system pH of the red soil nickel ore iron and aluminum removal solution is conducive to the precipitation reaction, which can reduce the use of precipitants.

[0013] In addition, the MHP precipitation method of the present application can directly prepare a product with a nickel-cobalt-manganese ratio that meets the requirements of the ternary precursor to be prepared, by using red soil nickel ore.

[0014] Preferably, the red soil nickel ore iron and aluminum removal solution in step (1) comprises 2-7 g / L of Ni, such as 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, such as 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, such as 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 within the value range are also applicable.

[0015] The laterite nickel ore iron and aluminum removal liquid preferably contains a low nickel and cobalt concentration, which can improve the content of nickel and cobalt in the prepared MHP.

[0016] Preferably, the Al content in the laterite nickel ore iron and aluminum removal liquid in step (1) 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 in the value range are also applicable.

[0017] Preferably, the Fe content in the laterite nickel ore iron and aluminum removal liquid in step (1) 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 in the value range are also applicable.

[0018] Preferably, the Zn content in the laterite nickel ore iron and aluminum removal liquid in step (1) 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 in the value range are also applicable.

[0019] Preferably, the Ca content in the laterite nickel ore iron and aluminum removal liquid in step (1) 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 in the value range are also applicable.

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

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

[0022] If the precipitation reaction time 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 and cobalt solution will be oxidized, which will accelerate the manganese hydrolysis and cause the manganese content in MHP to increase significantly. In addition, the nickel and cobalt precipitation rate will also decrease, which will increase the amount of alkali used.

[0023] Preferably, the temperature of the precipitation reaction is 55-75℃, for example, it can be 55℃, 60℃, 65℃, 70℃ or 75℃, but is not limited to the listed values, and other values not listed in the value range are also applicable.

[0024] If the temperature of the precipitation reaction is too low, the crystal growth is slow, the particle size of the obtained MHP is small, the filtration performance is poor, and the water content is high. If the reaction temperature is too high, the temperature needs to be increased by passing steam or the like, which will increase the cost.

[0025] Preferably, the complex alkali includes 15-95wt% of sodium carbonate, for example, it can be 15wt%, 25wt%, 35wt%, 45wt%, 55wt%, 65wt%, 75wt%, 85wt% or 95wt%, 5-85wt% of sodium hydroxide, for example, it can be 5wt%, 15wt%, 25wt%, 35wt%, 45wt%, 55wt%, 65wt%, 75wt% or 85wt%, but is not limited to the listed values, and other values not listed in the value range are also applicable.

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

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

[0028] The mass fraction of the complex alkali solution should not be too high, which is easy to form local over-alkalization. When the proportion of sodium carbonate in the complex alkali solution increases, the concentration of the complex alkali solution can be moderately increased. The mass fraction of the complex alkali solution should not be too low, otherwise the nickel and cobalt solution will be severely diluted, which not only increases the amount of alkali used in the MHP precipitation process, but also reduces the production efficiency.

[0029] Preferably, the ratio of the total molar amount of the complex alkali to the total molar amount of nickel and cobalt in the iron and aluminum removed laterite nickel ore solution is 1.4-2.5, 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 values not listed in the value range are also applicable.

[0030] When the above-mentioned molar ratio is too low, the MHP quality is high, but the nickel and cobalt precipitation rate is low, resulting in a significant decrease in equipment utilization and product production efficiency, while when the molar ratio is too high, the MHP quality will be reduced.

[0031] Preferably, the complex alkali solution is mixed by adding the complex alkali into water or industrial water.

[0032] Preferably, the post-treatment comprises a thickening treatment and a solid-liquid separation in sequence.

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

[0034] The part of the underflow after the thickening is returned to the MHP precipitation reaction system as a crystal seed, promoting the growth of MHP crystal grains and thus improving the filtration performance of the MHP.

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

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

[0037] The use of distilled water or industrial water to wash the MHP filter cake can remove soluble sulfate and other impurity components, thereby improving the purity of the MHP.

[0038] The use of distilled water or industrial water to wash the MHP filter cake can remove soluble sulfate and other impurity components, thereby improving the purity of the MHP.

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

[0040] Preferably, in the MHP, the Ni content is 40-43wt%, for example, it can be 40wt%, 40.5wt%, 41wt%, 41.5wt%, 42wt%, 42.5wt% or 43wt%, the Co content is 3.2-4.3wt%, for example, it can be 3.2wt%, 3.3wt%, 3.4wt%, 3.5wt%, 3.6wt%, 3.7wt%, 3.8wt%, 3.9wt%, 4.0wt%, 4.1wt%, 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, other values not listed within the value range are also applicable.

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

[0042] The application of the MHP includes preparing a ternary precursor material.

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

[0044] The present application uses a complex system of sodium hydroxide and sodium carbonate as a precipitant to prepare MHP, wherein sodium carbonate is a strong electrolyte and a strong base weak acid salt, and MHP is prepared under the cooperation 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, which is of great significance to reducing the cost of subsequent MHP extraction refining to prepare crystals; and the reaction rate is controllable, and the obtained MHP has better filtration performance and its water content is less than 50%. DETAILED DESCRIPTION

[0045] The technical solutions of the present application will be further described through specific embodiments. Those skilled in the art should understand that the embodiments are only to help understand the present application and should not be regarded as specific limitations of the present application.

[0046] The following examples and comparative examples use the liquid after removing iron and aluminum from laterite nickel ore, which is obtained after acid leaching and two-stage removal of iron and aluminum from laterite nickel ore, wherein the main components of the liquid after removing iron and aluminum from laterite nickel ore are shown in Table 1:

[0047] Table 1

[0048]

[0049] Example 1

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

[0051] (1) Prepare a complex alkali solution: add 38.37 g of complex alkali as a precipitant to industrial water and stir for 10 min to obtain a complex alkali solution, the mass fraction of the complex alkali solution is 10%, and the complex alkali includes 10 wt% of sodium carbonate and 90 wt% of sodium hydroxide;

[0052] (2) MHP precipitation: The prepared complex alkali solution was added into 10 L of the iron and aluminum removal solution of laterite nickel ore to react, the reaction temperature was 60°C, and the reaction time was 2 h, to obtain MHP slurry;

[0053] (3) Thickening: The MHP slurry was subjected to thickening treatment to obtain thickened supernatant and MHP underflow;

[0054] (4) Filtration: The MHP underflow was filtered, and the MHP filter cake was washed with industrial water.

[0055] Example 2

[0056] The present example provides a MHP precipitation method based on a complex alkali precipitant, which is the same as example 1 except that the complex alkali is 15wt% sodium carbonate and 85wt% sodium hydroxide.

[0057] Example 3

[0058] The present example provides a MHP precipitation method based on a complex alkali precipitant, which is the same as example 1 except that the complex alkali is 20wt% sodium carbonate and 80wt% sodium hydroxide.

[0059] Example 4

[0060] The present example provides a MHP precipitation method based on a complex alkali precipitant, which is the same as example 1 except that the complex alkali is 35wt% sodium carbonate and 65wt% sodium hydroxide.

[0061] Example 5

[0062] The present example provides a MHP precipitation method based on a complex alkali precipitant, which is the same as example 1 except that the complex alkali is 60wt% sodium carbonate and 40wt% sodium hydroxide.

[0063] Example 6

[0064] The present example provides a MHP precipitation method based on a complex alkali precipitant, which is the same as example 1 except that the complex alkali is 85wt% sodium carbonate and 15wt% sodium hydroxide.

[0065] Comparative Example 1

[0066] The present comparative example provides a MHP precipitation method, which is the same as example 1 except that the sodium carbonate in the complex alkali is replaced with sodium hydroxide of the same mass, and pure sodium hydroxide is used as the precipitant.

[0067] Comparative Example 2

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

[0069] Comparative Example 3

[0070] The present comparative example provides a MHP precipitation method which is the same as that of Example 1 except that sodium hydroxide in the compounded alkali is replaced by sodium carbonate with the same mass, and pure sodium carbonate is used as the precipitant.

[0071] The MHP components obtained in the above examples and comparative examples are tested by ICP method, and the results are shown in Table 2 below, which also includes the content of sodium carbonate in the precipitant; at the same time, the MHP filter cakes obtained in each example and comparative example are dried, and the water content is tested.

[0072] Table 2

[0073]

[0074]

[0075] From the above table, it can be seen that:

[0076] (1) Compared with Comparative Example 1, the Mn content of Comparative Example 1 is 6.02wt%, and the addition of sodium carbonate has an important influence on the precipitation rate of nickel, cobalt and manganese and the MHP component. Within a certain range, with the increase of the mass fraction of sodium carbonate in the compounded alkali (10%-85wt%), the nickel content and cobalt content in the prepared MHP increase, the manganese content decreases, and the magnesium content changes little. Moreover, the method of the present application can prepare high-quality MHP using the compounded alkali as the precipitant, and the water content of the MHP filter cake can be optimized to about 46%, which indicates that the MHP particles prepared by the present application have good filtration performance and are beneficial to reduce the water content.

[0077] (2) As can be seen from Example 6 and Comparative Examples 2-3, in Comparative Example 2, all sodium carbonate is used, and when the amount of sodium carbonate is increased to 1.5 times the theoretical amount of sodium hydroxide used for precipitating MHP, the manganese content in MHP rapidly increases to 9.21%, which makes the nickel content in the precipitate rapidly decrease to 31.17% and the cobalt content also decrease accordingly. Obviously, the manganese and magnesium contents in the MHP prepared by using sodium carbonate alone as the precipitant increase significantly, and the nickel and cobalt contents are obviously lower. Therefore, the quality of the MHP prepared by using sodium carbonate alone as the precipitant is obviously poorer than that prepared by using the compounded system of sodium hydroxide and sodium carbonate as the precipitant.

[0078] In summary, the application provides a MHP precipitation method based on a compound alkali precipitant and application thereof, which can greatly reduce the content of manganese in MHP, improve the content of nickel and cobalt, has important significance for reducing the cost of subsequent MHP refining to prepare crystals, and makes the reaction rate more controllable, the obtained MHP has better filtration performance and lower water content.

[0079] The above merely describes a specific implementation of the present application, but the protection scope of the present application is not limited thereto, and those skilled in the art should understand that any changes or replacements within the technical scope disclosed by the present application, which can be easily thought of by any person skilled in the art, falls within the protection scope and disclosure scope of the present application.

Claims

1. A method for MHP precipitation based on a compound alkaline precipitant, characterized in that, The MHP precipitation method includes the following steps: (1) The iron and aluminum removed liquid of laterite nickel ore is mixed with a compound alkaline solution to carry out a precipitation reaction to obtain nickel-cobalt hydroxide slurry; the compound alkaline solution is a mixture of sodium carbonate and sodium hydroxide, and the compound alkaline solution includes 60~85 wt% sodium carbonate and 15~40 wt% sodium hydroxide. (2) The nickel-cobalt hydroxide slurry described in step (1) is post-processed to separate MHP; The ratio of the total molar amount of the compound alkali in step (1) to the total molar amount of nickel and cobalt in the liquid after iron and aluminum removal from laterite nickel ore is 1.4 to 2.5; the content of the compound alkali in the compound alkali solution in step (1) is 9 to 13 wt%.

2. The MHP precipitation method according to claim 1, characterized in that, The liquid obtained after removing iron and aluminum from the laterite nickel ore in step (1) contains 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, characterized in that, In step (1), the Al content in the liquid after removing iron and aluminum from the laterite nickel ore is below 0.03 g / L.

4. The MHP precipitation method according to claim 1, characterized in that, In step (1), the Fe content in the liquid after removing iron and aluminum from the laterite nickel ore is below 0.002 g / L.

5. The MHP precipitation method according to claim 1, characterized in that, In step (1), the Zn content in the liquid after removing iron and aluminum from the laterite nickel ore is below 0.03 g / L.

6. The MHP precipitation method according to claim 1, characterized in that, In step (1), the Ca content in the liquid after removing iron and aluminum from the laterite nickel ore is below 0.7 g / L.

7. The MHP precipitation method according to claim 1, characterized in that, The precipitation reaction in step (1) takes 0.5 to 10 hours.

8. The MHP precipitation method according to claim 7, characterized in that, The precipitation reaction in step (1) takes 0.5-6 hours.

9. The MHP precipitation method according to claim 1, characterized in that, The precipitation reaction in step (1) is carried out at a temperature of 55~75 ℃.

10. The MHP precipitation method according to claim 1, characterized in that, The compound alkali solution in step (1) is obtained by mixing compound alkali with water or industrial water.

11. The MHP precipitation method according to claim 1, characterized in that, The post-processing in step (2) includes a thickening process and a solid-liquid separation performed sequentially.

12. The MHP precipitation method according to claim 11, characterized in that, The concentrated material is partially recycled as seed crystals in the precipitation reaction.

13. The MHP precipitation method according to claim 11, characterized in that, The solid-liquid separation includes vacuum filtration or filter press filtration.

14. The MHP precipitation method according to claim 11, characterized in that, During the solid-liquid separation, the MHP filter cake is washed with distilled water or industrial water.

15. An MHP, characterized in that, The MHP is obtained by precipitation using the MHP precipitation method as described in any one of claims 1-14.

16. The MHP according to claim 15, characterized in that, The MHP contains 42-43 wt% Ni, 4.1-4.3 wt% Co, 2.5-3.5 wt% Mn, and 0.4-0.6 wt% Mg.

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