Method for preparing MHP based on oxidation precipitation method

Abstract

The invention provides a method for preparing MHP based on an oxidation precipitation method, and the method comprises the following steps: (1) mixing laterite-nickel ore iron and aluminum removed liquid, a composite oxidant and a magnesium oxide precipitator, and carrying out precipitation reaction to obtain MHP slurry; and (2) carrying out post-treatment on the MHP slurry to obtain an MHP product. According to the method, the iron and aluminum removed liquid obtained after laterite-nickel ore acid leaching is used, the manganese content in the obtained MHP can be adjusted and controlled by adding the composite oxidizing agent and the magnesium oxide precipitating agent, and the quality of the prepared MHP is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of hydrometallurgy and relates to a method for preparing MHP based on an oxidation precipitation method. Background Art

[0002] With the rapid development of the new energy industry, the demand for nickel in power batteries has skyrocketed. The hydrometallurgical production of nickel-cobalt hydroxide (MHP) from nickel ore, a key method for obtaining nickel, plays a crucial role in the entire industry chain. MHP is not only a fundamental raw material for nickel alloys but also has widespread applications in electroplating, catalysts, batteries, and other fields.

[0003] Currently, the process of preparing MHP from laterite nickel ore using hydrometallurgical methods has been widely used, but many problems remain to be solved. In terms of manganese content, existing processes are often unable to fully recover the manganese element from laterite nickel ore. Taking the common limonite-type laterite nickel ore as an example, after high-pressure leaching, two-stage neutralization and iron and aluminum removal, the manganese precipitation rate in the first nickel and cobalt precipitation process is usually only around a dozen percent. Most of the manganese is precipitated with lime milk and then treated as waste landfill, which not only results in a huge waste of resources but also increases the cost and environmental pressure of subsequent waste treatment. From the perspective of the entire industry, increasing the manganese content in MHP and achieving efficient recovery of manganese are of great significance for improving the comprehensive utilization rate of resources and reducing production costs.

[0004] CN114854987A discloses a nickel-cobalt precipitation method for a laterite nickel ore acid leaching solution for removing iron and aluminum. The precipitation method comprises: S100, adding a reducing agent to the laterite nickel ore acid leaching solution for removing iron and aluminum; S200, continuously passing the mixed solution into a reactor for a alkali-transfer precipitation reaction; S300, continuously performing a thickening separation treatment on the precipitated slurry; S400, adding a precipitation inducer to a portion of the overflow for a alkali-transfer reaction to obtain an alkali-transfer overflow, and mixing and homogenizing the alkali-transfer overflow with a first portion of underflow to form an alkali-transfer slurry; alternatively, adding a precipitation inducer to the first portion of the underflow for a alkali-transfer reaction to form an alkali-transfer slurry; S500, continuously passing the alkali-transfer slurry into a reactor for a alkali-transfer precipitation reaction; and S600, filtering and washing the second portion of the underflow to obtain an MHP product.

[0005] CN116806272A discloses a comprehensive utilization method of laterite nickel ore, comprising the following steps: (1) beneficiating the laterite nickel ore to obtain chromium concentrate, low-nickel and low-magnesium ore, and high-nickel and high-magnesium ore; (2) pulping the low-nickel and low-magnesium ore to obtain ore pulp, leaching the ore pulp, neutralizing, continuously countercurrent washing, and solid-liquid separation to obtain filtrate and filter residue, neutralizing and removing impurities from the filtrate to obtain iron-aluminum slag and a solution containing nickel and cobalt, and precipitating nickel and cobalt to obtain nickel cobalt hydroxide.

[0006] Although the above scheme recovers nickel and cobalt from laterite nickel ore, the quality of the obtained MHP is low. Summary of the Invention

[0007] The present invention aims to provide a method for preparing MHP based on an oxidation precipitation method. The method uses the iron-deoxidized aluminum solution obtained by acid leaching laterite nickel ore. By adding a composite oxidant and a magnesium oxide precipitant, the manganese content in the obtained MHP can be adjusted and the quality of the obtained MHP can be improved.

[0008] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0009] In a first aspect, the present invention provides a method for preparing MHP based on an oxidative precipitation method, the method comprising the following steps:

[0010] (1) mixing a laterite nickel ore liquid after iron and aluminum removal, a composite oxidant, and a magnesium oxide precipitant to perform a precipitation reaction to obtain an MHP slurry;

[0011] (2) Post-processing the MHP slurry to obtain an MHP product.

[0012] The present invention uses a solution obtained by acid leaching laterite nickel ore to obtain a de-ironized and aluminum-free solution to prepare MHP. During the precipitation reaction to prepare MHP, a composite oxidant is added in combination with a magnesium oxide precipitant. The magnesium oxide precipitant slowly dissolves in the solution to generate Mg(OH)2, gradually releasing OH-, causing the pH of the system to rise gently. The reaction is stable and highly controllable, reducing the participation of impurities in the reaction. The composite oxidant has a wide oxidation potential range and is applicable over a wide pH range. It can oxidize divalent manganese in the solution to a higher valence state, forming insoluble MnOOH or MnO2. These high-valent manganese compounds are more easily removed from the liquid phase by adsorption or coprecipitation under weakly alkaline conditions and incorporated into the MHP. The method of the present invention can effectively regulate the manganese content in the MHP for manganese recovery, while further reducing the moisture content of the MHP.

[0013] In the method of the present invention, magnesium oxide is precipitated into MHP by the principle of dissolution and ionization (MgO+H2O→Mg(OH)2,Mg(OH)2→Mg 2+ +2OH - ), where magnesium oxide has a very low solubility, eliminating the problem of localized over-alkalinity. In the magnesium oxide-based MHP precipitation reaction system, nickel, cobalt, manganese, and magnesium tend to precipitate according to their hydrolysis order. Therefore, compared to liquid caustic soda, MHP prepared from magnesium oxide has a larger particle size and significantly improved filterability. Furthermore, MHP has higher nickel and cobalt content, lower magnesium impurity content, and lower moisture content.

[0014] The present invention promotes the oxidation of Mn by using a composite oxidant in the process of magnesium oxide precipitation of MHP.2+ Rapid oxidation to better crystallized MnO2, while recovering manganese, solves the current MHP precipitation process of Mn 2+ The conversion to MnOOH and amorphous MnO2 brings problems of impurities and moisture entrainment to MHP.

[0015] Preferably, the laterite nickel ore liquid after iron and aluminum removal in step (1) is prepared by the following method:

[0016] The laterite nickel ore is subjected to acid leaching treatment to obtain a laterite nickel ore acid leaching solution, the laterite nickel ore acid leaching solution is mixed with a neutralizing agent for neutralization reaction, and then subjected to solid-liquid separation treatment to obtain a laterite nickel ore liquid after iron and aluminum removal.

[0017] Preferably, the neutralizing agent includes any one of sodium hydroxide, sodium carbonate, magnesium oxide, potassium hydroxide or calcium carbonate, or a combination of at least two thereof. Typical but non-limiting combinations include a combination of sodium carbonate and magnesium carbonate, a combination of sodium hydroxide and potassium hydroxide, or a combination of sodium carbonate and calcium carbonate.

[0018] Preferably, the temperature of the neutralization reaction is 60°C to 80°C, for example, 60°C, 65°C, 70°C, 75°C or 80°C, etc., and is not limited to the listed values. Other values not listed within the numerical range are also applicable.

[0019] Preferably, the endpoint pH of the neutralization reaction is 2 to 6, for example, 2, 3, 4, 5 or 6, etc., and is not limited to the listed values. Other values not listed within the numerical range are also applicable.

[0020] Preferably, the neutralization reaction time is 4 h to 8 h, for example, 4 h, 5 h, 6 h, 7 h or 8 h, etc., and is not limited to the listed values. Other values not listed within the numerical range are also applicable.

[0021] Preferably, after the neutralization reaction, iron-aluminum slag sedimentation treatment is further performed before solid-liquid separation treatment.

[0022] Preferably, the composite oxidant in step (1) comprises a primary oxidant and a secondary oxidant.

[0023] Preferably, the primary oxidant comprises a solid peroxide oxidant and / or a manganese-containing oxidant.

[0024] In the composite oxidant of the present invention, if a solid peroxide oxidant is selected as the main oxidant, the sodium hydroxide and hydrogen peroxide generated by the reaction of the two peroxides with water can simultaneously provide OH-precipitated manganese and nickel-cobalt ions while oxidizing divalent manganese ions. If a manganese-containing oxidant is selected as the main oxidant, it can oxidize manganese ions, and the manganese dioxide formed after its reduction can provide the crystal nuclei required for the precipitation of nickel-cobalt ions.

[0025] Preferably, the solid peroxide oxidant comprises Na2O2 and / or K2O2.

[0026] Preferably, the manganese-containing oxidant comprises K2MnO4 and / or KMnO4.

[0027] Preferably, the secondary oxidant comprises NaClO and / or H2O2.

[0028] Preferably, the Mn in the liquid after the iron and aluminum removal of the laterite nickel ore in step (1) 2+ Oxidized to Mn 4+ The molar amount of the required composite oxidant is 100%, and the added amount of the composite oxidant is 0.01% to 100%, for example: 0.01%, 0.5%, 1%, 10% or 100%, etc., not limited to the listed values, and other values not listed within the numerical range are also applicable.

[0029] The Mn in the laterite nickel ore after iron and aluminum removal of the present invention 2+ Oxidized to Mn 4+ The molar amount of the required composite oxidant needs to be determined according to the properties of the oxidant itself. For example, the solution after iron and aluminum removal from nickel ore contains 1 mol of Mn 2+ If potassium permanganate is used as an oxidant, 1 mol of KMnO4 can oxidize 2 mol of Mn2 + to Mn 4+ , then the required molar amount of potassium permanganate is 0.5 mol, then the amount of potassium permanganate added is 0.00005 mol~0.5 mol, and using H2O2 as the oxidant, 1 mol of Na2O2 can oxidize 0.5 mol of Mn2 + to Mn 4+ , then the required molar amount of Na2O2 is 2 mol, and the added amount of Na2O2 is 0.0002 mol to 2 mol, that is, the added amount of the composite oxidant of the present invention is one ten-thousandth to one of the amount required to oxidize divalent manganese to tetravalent manganese (this is just an example, so only a single oxidant is used).

[0030] Preferably, the temperature of the precipitation reaction in step (1) is 40°C to 85°C, for example, 40°C, 45°C, 50°C, 60°C or 85°C, etc., and is not limited to the listed values. Other values not listed within the numerical range are also applicable.

[0031] Preferably, the endpoint pH of the precipitation reaction in step (1) is 6.8 to 7.5, for example, 7.3, 7.35, 7.4, 7.45 or 7.5, etc., and is not limited to the listed values. Other values not listed within the numerical range are also applicable.

[0032] Preferably, the precipitation reaction time in step (1) is 2 h to 8 h, for example, 2 h, 3 h, 5.5 h, 6 h or 8 h, etc., and is not limited to the listed values. Other values not listed within the numerical range are also applicable.

[0033] Preferably, the post-treatment in step (2) includes thickening the MHP slurry and then performing solid-liquid separation on the bottom flow obtained by the thickening treatment.

[0034] Preferably, the solid-liquid separation treatment includes pressure filtration and / or suction filtration.

[0035] Compared with the prior art, the present invention has the following beneficial effects:

[0036] (1) The method of the present invention uses the iron-deoxidized aluminum solution obtained after acid leaching of laterite nickel ore. By adding a composite oxidant and a magnesium oxide precipitant, the manganese content in the obtained MHP can be adjusted to improve the quality of the obtained MHP.

[0037] (2) In the MHP prepared by the method of the present invention, the nickel content is guaranteed to be above 42.6% and the cobalt content is guaranteed to be above 4.1%. The manganese content can reach above 6.8%, the impurity magnesium content can reach below 1.63%, and the moisture content can reach below 45%. By adjusting the parameters in the preparation process, the manganese content in the MHP can be achieved to be above 8.3%, the impurity magnesium content can be achieved to be below 1.02%, and the moisture content can be achieved to be below 40.2%. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 Schematic diagram of the process for preparing MHP based on oxidation precipitation method provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0039] The technical solution of the present invention is further described below by way of specific embodiments. It should be understood by those skilled in the art that the embodiments are merely to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0040] The iron-aluminum-removed liquid from laterite nickel ore in the examples of the present invention and the comparative examples was prepared by the following method:

[0041] The laterite nickel ore is subjected to acid leaching to obtain a laterite nickel ore acid leaching solution, which is mixed with sodium hydroxide and subjected to a neutralization reaction at 70° C. for 6 hours. After the end point pH of the neutralization reaction is 4, the material obtained by the neutralization reaction is subjected to an iron-aluminum slag sedimentation treatment and then to a solid-liquid separation treatment to obtain a laterite nickel ore liquid after iron and aluminum removal.

[0042] The main ion composition of the laterite nickel ore after iron and aluminum removal is as follows:

[0043] Nickel is 3.87g / L, cobalt is 0.41g / L, manganese is 2.73g / L, and magnesium is 6.44g / L.

[0044] Example 1

[0045] This embodiment provides a method for preparing MHP based on oxidation precipitation method. The process flow diagram of the method is shown in FIG. Figure 1 As shown, the method includes the following steps:

[0046] (1) A magnesium oxide precipitant is added to the liquid after iron and aluminum removal of laterite nickel ore to carry out a precipitation reaction, and a composite oxidant is added during the precipitation reaction. The precipitation reaction temperature is 60° C., the precipitation reaction time is 6 h, and the end point pH of the precipitation reaction is 7.2. After the precipitation reaction, an MHP slurry is obtained, wherein the composite oxidant includes Na2O2 and NaClO in a molar ratio of 1:1, and the addition amount of the composite oxidant is 1:1 of the Mn in the liquid after iron and aluminum removal of laterite nickel ore. 2+ Oxidized to Mn 4+ 0.05% of the theoretical molar amount of the required complex oxidant;

[0047] (2) The MHP slurry is thickened and the bottom flow product of the thickening treatment is subjected to filter press treatment to obtain the MHP product.

[0048] Example 2

[0049] This embodiment provides a method for preparing MHP based on oxidation precipitation method. The process flow diagram of the method is shown in FIG. Figure 1 As shown, the method includes the following steps:

[0050] (1) A magnesium oxide precipitant is added to the liquid after iron and aluminum removal of laterite nickel ore to carry out a precipitation reaction, and a composite oxidant is added during the precipitation reaction. The precipitation reaction temperature is 40°C, the precipitation reaction time is 8 hours, and the end point pH of the precipitation reaction is 6.8. After the precipitation reaction, MHP slurry is obtained, wherein the composite oxidant includes Na2O2 and H2O2 with a molar ratio of 1:1, and the addition amount of the composite oxidant is 1:1. 2+ Oxidized to Mn 4+ 0.01% of the theoretical molar amount of the required complex oxidant;

[0051] (2) The MHP slurry is subjected to a thickening treatment, and the material obtained from the thickening underflow is subjected to a filter press treatment to obtain an MHP product.

[0052] Example 3

[0053] This embodiment provides a method for preparing MHP based on oxidation precipitation method. The process flow diagram of the method is shown in FIG. Figure 1 As shown, the method includes the following steps:

[0054] (1) A magnesium oxide precipitant is added to the liquid after iron and aluminum removal of laterite nickel ore to carry out a precipitation reaction, and a composite oxidant is added during the precipitation reaction. The precipitation reaction temperature is 85° C., the precipitation reaction time is 2 h, and the end point pH of the precipitation reaction is 7.5. After the precipitation reaction, an MHP slurry is obtained, wherein the composite oxidant includes KMnO4 and NaClO in a molar ratio of 2:1, and the addition amount of the composite oxidant is the amount of Mn in the liquid after iron and aluminum removal of laterite nickel ore. 2+ Oxidized to Mn 4+ 0.1% of the theoretical molar amount of the required complex oxidant;

[0055] (2) The MHP slurry is subjected to a thickening treatment, and the material obtained from the thickening underflow is subjected to a filter press treatment to obtain an MHP product.

[0056] Example 4

[0057] The only difference between this embodiment and embodiment 1 is that the endpoint pH of the precipitation reaction is 6.5, and the other conditions and parameters are exactly the same as those in embodiment 1.

[0058] Example 5

[0059] The only difference between this embodiment and embodiment 1 is that the endpoint pH of the precipitation reaction is 7.8, and the other conditions and parameters are exactly the same as those in embodiment 1.

[0060] Example 6

[0061] The only difference between this embodiment and embodiment 1 is that the precipitation reaction time is 1 hour, and the other conditions and parameters are exactly the same as those in embodiment 1.

[0062] Example 7

[0063] The only difference between this embodiment and embodiment 1 is that the precipitation reaction time is 10 hours, and the other conditions and parameters are exactly the same as those in embodiment 1.

[0064] Comparative Example 1

[0065] The only difference between this comparative example and Example 1 is that magnesium oxide is replaced with an equal mass of sodium hydroxide, and other conditions and parameters are exactly the same as those in Example 1.

[0066] Comparative Example 2

[0067] The only difference between this comparative example and Example 1 is that only Na2O2 is added as the oxidant, and the other conditions and parameters are exactly the same as those in Example 1.

[0068] Test results:

[0069] The manganese content, impurity magnesium content and moisture content of the MHP prepared in the examples and comparative examples were tested. The test results are shown in Table 1:

[0070] Table 1

[0071]

[0072]

[0073] As can be seen from Table 1, according to Examples 1-7, in the MHP prepared by the method of the present invention, the nickel content is ensured to be above 42.6% and the cobalt content is above 4.1%, the manganese content can reach above 6.8%, the impurity magnesium content can reach below 1.63%, and the moisture content can reach below 45%. By adjusting the conditions and parameters in the preparation process, the manganese content in the prepared MHP can reach above 8.3%, the impurity magnesium content can reach below 1.02%, and the moisture content can reach below 40.2%.

[0074] A comparison of Example 1 and Examples 4-5 shows that in the method for preparing MHP based on the oxidative precipitation method of the present invention, the endpoint pH of the precipitation reaction affects the quality of the MHP produced. Controlling the endpoint pH of the precipitation reaction between 6.8 and 7.5 produces higher-quality MHP. If the endpoint pH of the precipitation reaction is too low, the reaction is incomplete, resulting in a low manganese content in the MHP and reduced quality. If the endpoint pH of the precipitation reaction is too high, the reaction is excessive, and although the manganese content in the MHP is slightly increased, the impurities and water content are significantly increased, resulting in reduced quality.

[0075] A comparison of Example 1 and Examples 6-7 shows that in the method for preparing MHP based on the oxidative precipitation method of the present invention, the precipitation reaction time affects the quality of the MHP produced. Controlling the precipitation reaction time to 2 to 8 hours produces higher-quality MHP. If the precipitation reaction time is too short, the reaction is incomplete, resulting in a low manganese content in the MHP and reduced quality. If the precipitation reaction time is too long, the reaction is excessive, and although the manganese content in the MHP is slightly increased, the impurities and moisture content are significantly increased, resulting in reduced quality.

[0076] As can be seen from the comparison between Example 1 and Comparative Examples 1-2, the present invention adds a composite oxidant and an oxide precipitant in the method. The oxide precipitant slowly dissolves in the solution to generate Mg(OH)2, gradually releasing OH-, causing the pH of the system to rise gently. The reaction is stable and highly controllable, and the participation of impurities in the reaction can be reduced. The composite oxidant has a wide oxidation potential range and a wide applicable pH range. It can oxidize divalent manganese in the solution to a higher valence state to form insoluble MnOOH or MnO2. These high-valent manganese compounds are more easily removed from the liquid phase by adsorption or coprecipitation under weakly alkaline conditions and are doped into the MHP. However, when conventional sodium hydroxide is used as a precipitant, the pH in the system changes rapidly, and local overalkalinity is difficult to control, resulting in a decrease in the quality of the MHP. If a single oxidant is used, the applicable pH range of the oxidant is small, the oxidation potential range is limited, and it is difficult to completely oxidize the manganese, resulting in a decrease in the manganese doping amount and a lower quality of the obtained MHP.

[0077] The applicant declares that the above is only a specific embodiment of the present invention, but the scope of protection 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 fall within the scope of protection and disclosure of the present invention.

Claims

1. A method for preparing MHP based on oxidation precipitation method, characterized in that: The method comprises the following steps: (1) mixing a laterite nickel ore liquid after iron and aluminum removal, a composite oxidant, and a magnesium oxide precipitant to perform a precipitation reaction to obtain an MHP slurry; (2) Post-processing the MHP slurry to obtain an MHP product.

2. The method according to claim 1, wherein The composite oxidant in step (1) includes a main oxidant and a secondary oxidant.

3. The method according to claim 2, wherein The primary oxidant includes a solid peroxide oxidant and / or a manganese-containing oxidant. Preferably, the solid peroxide oxidant comprises Na2O2 and / or K2O2; Preferably, the manganese-containing oxidant comprises K2MnO4 and / or KMnO 4。 4. The method according to claim 2, wherein The secondary oxidant includes NaClO and / or H2O2.

5. The method according to any one of claims 1 to 4, characterized in that Mn in the liquid after removing iron and aluminum from the laterite nickel ore in step (1) 2+ Oxidized to Mn 4+ Based on the molar amount of the required composite oxidant being 100%, the added amount of the composite oxidant is 0.01% to 100%.

6. The method according to any one of claims 1 to 5, wherein: The temperature of the precipitation reaction in step (1) is 40°C to 85°C.

7. The method according to any one of claims 1 to 6, wherein: The endpoint pH of the precipitation reaction in step (1) is 6.8-7.

5.

8. The method according to any one of claims 1 to 7, wherein: The precipitation reaction time in step (1) is 2h to 8h.

9. The method according to any one of claims 1 to 8, wherein The post-treatment in step (2) includes thickening the MHP slurry and then performing solid-liquid separation on the bottom flow obtained from the thickening treatment.

10. The method according to claim 9, wherein The solid-liquid separation process includes pressure filtration and / or suction filtration.

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