A method for preparing MHP using a composite precipitant

Abstract

This invention relates to a method for preparing MHP using a composite precipitant; the method includes the following steps: first, mixing laterite nickel ore after iron and aluminum removal, magnesium precipitant, and carbonate precipitant to carry out a precipitation reaction to obtain MHP slurry; the carbonate precipitant is sodium carbonate; then, the MHP slurry is thickened, and the resulting thickened underflow is subjected to solid-liquid separation to obtain the MHP product; the method controls the MHP crystallization process to regulate the ratio of nickel, cobalt, and manganese in the MHP product, and reduces its Mg content and water content, wherein the Ni content is preferably as high as 40.0 wt% or more, the Co content is preferably as high as 3.0 wt% or more, and the Mn content is controllable in the range of 3.3 to 10.0 wt%, while reducing the Mg content and water content, with the Mg content preferably as low as 1.5 wt% and the water content preferably as low as 43.2%, to obtain a high-quality MHP product.

Description

Technical Field

[0001] This invention relates to the field of hydrometallurgical technology, and in particular to a method for preparing MHP using a composite precipitant. Background Technology

[0002] Nickel-cobalt hydroxide (MHP) is an intermediate product in the hydrometallurgical process of laterite nickel ore. It is an important raw material for the cathode materials of lithium-ion batteries and nickel-cobalt-manganese (NCM) batteries, and can also be used to produce nickel sulfate, refined nickel-cobalt hydroxide, and nickel plates, showing promising application prospects. Currently, the main methods for preparing MHP products in the hydrometallurgical process of laterite nickel ore include seed growth and direct precipitation reaction. However, existing seed growth processes generally require recycling about 90% of the seed crystals for re-growth, meaning that only about 10% is grown each time, resulting in long seed growth times and low production efficiency. The existing direct precipitation method for preparing MHP products is prone to localized over-alkaliness in the precipitation system, i.e., excessively high pH in the aqueous solution. This leads to the simultaneous precipitation of multiple metal ions (mainly nickel, cobalt, magnesium, and manganese ions), resulting in a poor-quality MHP precipitate with a high content of impurities and high water content. Therefore, researchers are dedicated to studying how to obtain high-quality MHP products that meet market demands.

[0003] For example, CN117120642A discloses a method for the continuous preparation of nickel-cobalt hydroxide by hydrometallurgical process of laterite nickel ore. It uses primary nickel-cobalt hydroxide precipitate particles as crystal nuclei and controls the product quality by controlling the precipitation process conditions. However, this method requires repeated precipitation reactions to make the crystal nuclei grow continuously. It also requires controlling parameters such as the seed return ratio, which is time-consuming and has low production efficiency. Moreover, the nickel-cobalt hydroxide product obtained has a low nickel-cobalt content and a high water content.

[0004] For example, CN119487226A discloses a method for magnesium-activated precipitation of MHP. This method solves the problem of local over-alkaliness when directly using sodium hydroxide solution to prepare MHP products by mixing magnesium-containing solution with sodium hydroxide solution in two-stage nickel-cobalt precipitation. However, this method is difficult to control the specific precipitation process, and there is still much room for improvement in the uniformity of nickel-cobalt element distribution in MHP products. Moreover, the obtained MHP products have high Mg content and high water content.

[0005] Therefore, how to provide a new method for preparing MHP using composite precipitants, and solve the problems of low production efficiency of traditional seed crystal growth process for preparing MHP and uneven nickel, cobalt and manganese ratio, high magnesium content and water content in the product due to local over-alkaliness in the existing direct precipitation reaction, so as to obtain high-quality MHP products, is an urgent problem to be solved in this field. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention provides a method for preparing MHP using a composite precipitant. This method achieves precise control over the MHP crystallization process, thereby controlling the ratio of nickel, cobalt, and manganese in the MHP product and reducing its Mg content and water content. It avoids the problem of low production efficiency caused by the need for cyclic regeneration of crystals in the traditional seed growth process for preparing MHP, as well as the problem of uneven distribution of nickel, cobalt, and manganese and high Mg content and water content caused by local over-alkaliness in the existing non-seed growth process, i.e., the direct precipitation reaction process. Ultimately, a high-quality MHP product is obtained.

[0007] To achieve this objective, the present invention adopts the following technical solution:

[0008] This invention provides a method for preparing MHP using a composite precipitant, the method comprising the following steps:

[0009] (1) Mix laterite nickel ore after iron and aluminum removal liquid, magnesium precipitant and carbonate precipitant to carry out precipitation reaction to obtain MHP slurry; the carbonate precipitant is sodium carbonate.

[0010] (2) The MHP slurry in step (1) is thickened, and the thickened underflow is separated into solid and liquid to obtain the MHP product.

[0011] The method of this invention involves compounding a magnesium precipitant with a carbonate precipitant, and selecting sodium carbonate as the carbonate precipitant. The method utilizes the OH- precipitant slowly released from the magnesium precipitant in the precipitation system. - OH generated by the ionization of sodium carbonate - The synergistic effect regulates the pH of the precipitation system, avoiding local over-alkaliness that leads to uneven nickel and cobalt distribution in MHP products, as well as increased Mg content and water content. This results in high-quality MHP products. Compared with the traditional method of preparing MHP using composite precipitants through seed growth, this method avoids the problem of low production efficiency caused by the need for seed regeneration, thus saving production costs.

[0012] Preferably, the liquid from the laterite nickel ore in step (1) after removing iron and aluminum contains nickel, cobalt, manganese and magnesium.

[0013] Preferably, the liquid obtained after removing iron and aluminum from the laterite nickel ore in step (1) contains 2-6 g / L nickel, 0.1-0.6 g / L cobalt, 1-6 g / L manganese and 4-12 g / L magnesium.

[0014] Among them, nickel is 2-6 g / L, for example, it can be 2 g / L, 2.5 g / L, 3 g / L, 3.5 g / L, 4 g / L, 4.5 g / L, 5 g / L, 5.5 g / L or 6 g / L, etc.; cobalt is 0.1-0.6 g / L, for example, it can be 0.1 g / L, 0.2 g / L, 0.3 g / L, 0.4 g / L, 0.5 g / L or 0.6 g / L, etc.; manganese is 1-6 g / L, for example, it can be 1.0 g / L, 1. 4 g / L, 1.8 g / L, 2.2 g / L, 2.6 g / L, 3.0 g / L, 3.4 g / L, 3.8 g / L, 4.0 g / L, 4.4 g / L, 4.8 g / L, 5.2 g / L, 5.6 g / L, or 6.0 g / L, etc.; 4 to 12 g / L magnesium, for example, 4 g / L, 5 g / L, 6 g / L, 7 g / L, 8 g / L, 9 g / L, 10 g / L, 11 g / L, or 12 g / L, etc.

[0015] Preferably, the magnesium compound in the magnesium precipitant in step (1) includes magnesium hydroxide and / or magnesium carbonate.

[0016] Preferably, the molar ratio of sodium carbonate in step (1) to magnesium compound in magnesium precipitant is (0.0001-5):1, for example, it can be 0.0001:1, 0.0005:1, 0.001:1, 0.005:1, 0.01:1, 0.05:1, 0.1:1, 0.5:1, 1:1, 1.5:1, 2:1, 2.5:1, 3:1, 3.5:1, 4:1, 4.5:1 or 5:1, etc.

[0017] It is worth noting that the present invention can control the pH of the precipitation system to 6.5-7.5 by controlling the molar ratio of sodium carbonate to magnesium compound in the magnesium precipitant in step (1) to be (0.0001-5):1.

[0018] Preferably, the magnesium precipitant in step (1) is obtained by mixing a magnesium-containing solution and an alkaline solution to undergo an alkaline conversion reaction.

[0019] Preferably, the magnesium-containing solution comprises the manganese-precipitated solution from laterite nickel ore.

[0020] Preferably, the concentration of magnesium ions in the magnesium-containing solution is 4 to 6 g / L, for example, it can be 4 g / L, 4.5 g / L, 5 g / L, 5.5 g / L or 6 g / L.

[0021] Preferably, the alkaline solution includes any one or a combination of at least two of sodium carbonate, ammonium carbonate, or sodium hydroxide, wherein typical but non-limiting combinations include combinations of sodium carbonate and ammonium carbonate, combinations of ammonium carbonate and sodium hydroxide, or combinations of sodium carbonate and sodium hydroxide, etc.

[0022] Preferably, the mass concentration of the alkaline solution is 0.5 to 30 wt%, for example, it can be 0.5 wt%, 1 wt%, 3 wt%, 5 wt%, 8 wt%, 10 wt%, 12 wt%, 15 wt%, 18 wt%, 20 wt%, 22 wt%, 25 wt%, 28 wt%, or 30 wt%.

[0023] Preferably, the amount of alkaline substance added to the alkaline solution is 10wt% to 100wt% of the theoretical amount required for complete precipitation of magnesium in the magnesium-containing solution. For example, it can be 10wt%, 20wt%, 30wt%, 40wt%, 50wt%, 60wt%, 70wt%, 80wt%, 90wt%, or 100wt%, etc., preferably 50wt% to 60wt%.

[0024] Preferably, the temperature of the alkali conversion reaction is 30 to 70°C, for example, it can be 30°C, 35°C, 40°C, 45°C, 50°C, 55°C, 60°C, 65°C or 70°C.

[0025] Preferably, the time for the alkali conversion reaction is 2 min to 10 min, for example, it can be 2 min, 4 min, 6 min, 8 min or 10 min.

[0026] Preferably, the mixing in step (1) further includes the addition of a composite oxidant.

[0027] This invention further incorporates a composite oxidant, which is used to remove iron and aluminum from the laterite nickel ore solution containing Mn. 2+ Oxidized to Mn 3+ This promotes the precipitation of manganese ions, thereby further increasing the Mn content in the MHP product. Furthermore, by adjusting the amount of the composite oxidant added, the Mn content in the MHP product can be controlled, thus meeting the market demand for MHP products with different Mn contents.

[0028] The present invention further preferably includes the addition of a composite oxidant in step (1) of the mixing process. The advantages of the composite oxidation include the ability to quickly form some high-valence manganese oxides in the early stage of the precipitation reaction, providing nucleation and crystallization sites for MHP. This improves the problem of explosive nucleation and agglomeration of a large number of crystal nuclei caused by local over-alkali in the early stage of the precipitation reaction. It also solves the problem that the simple air oxidation process is difficult to control the process conditions, which leads to the oxidation of manganese into colloidal MnOOH and amorphous manganese dioxide, resulting in MHP products being prone to impurities, high water content and difficult to filter.

[0029] Preferably, the composite oxidant includes a primary oxidant and a secondary oxidant.

[0030] Preferably, the main oxidant includes a solid peroxide oxidant and / or a manganese-containing oxidant, and more preferably a combination of a solid peroxide oxidant and the manganese-containing oxidant.

[0031] In this invention, the primary oxidant is preferably a combination of a solid peroxide oxidant and a manganese-containing oxidant, utilizing sodium hydroxide and hydrogen peroxide generated from the reaction of the peroxide with water to oxidize Mn. 2+ At the same time, it also provides OH - To precipitate manganese and nickel-cobalt ions; and to further oxidize Mn using the manganese-containing oxidant. 2+ Furthermore, the MnO2 formed after its reduction can provide the crystal nuclei required for nickel-cobalt ion precipitation. The two work synergistically to increase the proportion of nickel, cobalt, and manganese in MHP products.

[0032] Preferably, the solid peroxide oxidant includes Na2O2 and / or K2O2.

[0033] Preferably, the manganese-containing oxidant includes K2MnO4 and / or KMnO4.

[0034] Preferably, the secondary oxidant includes NaClO and / or H2O2.

[0035] Preferably, the mass concentration of the hydrogen peroxide is 5wt% to 30wt%, for example, it can be 5wt%, 8wt%, 10wt%, 12wt%, 15wt%, 18wt%, 20wt%, 22wt%, 25wt%, 28wt%, or 30wt%.

[0036] Preferably, the amount of composite oxidant added in step (1) is related to the amount of Mn in the liquid after iron and aluminum removal from the laterite nickel ore. 2+ All oxidized to Mn 3+ The required molar ratio of the theoretical amount of the composite oxidant is (0.0001 to 1):1, for example, it can be 0.0001:1, 0.0003:1, 0.0005:1, 0.0008:1, 0.001:1, 0.005:1, 0.01:1, 0.05:1, 0.1:1, 0.5:1 or 1:1, etc., preferably (0.0001 to 0.001):1.

[0037] Preferably, the temperature of the precipitation reaction in step (1) is 30 to 85°C, for example, it can be 30°C, 35°C, 40°C, 45°C, 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, 80°C or 85°C.

[0038] Preferably, the precipitation reaction time in step (1) is 1 to 8 hours, for example, 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, 7 hours or 8 hours, preferably 2 to 6 hours.

[0039] Preferably, the pH of the precipitation reaction in step (1) is 6.8 to 7.5, for example, it can be 6.8, 7.0, 7.2 or 7.5.

[0040] Preferably, the mixing in step (1) further includes the addition of an auxiliary precipitant.

[0041] Preferably, the molar ratio of the amount of the auxiliary precipitant added to the total amount of nickel and cobalt in the liquid after iron and aluminum removal from the laterite nickel ore is (0.1 to 0.9):1, for example, it can be 0.1:1, 0.2:1, 0.3:1, 0.4:1, 0.5:1, 0.6:1, 0.7:1, 0.8:1 or 0.9:1, etc.

[0042] Preferably, the auxiliary precipitant includes a complexing agent and / or a surfactant.

[0043] Preferably, the complexing agent comprises ethylenediaminetetraacetic acid and / or ammonia.

[0044] Preferably, the surfactant comprises any one or a combination of at least two of hexadecyltrimethylammonium bromide, sodium dodecylbenzenesulfonate, or polyethylene glycol, wherein typical but non-limiting combinations include combinations of hexadecyltrimethylammonium bromide and sodium dodecylbenzenesulfonate, combinations of hexadecyltrimethylammonium bromide and polyethylene glycol, or combinations of sodium dodecylbenzenesulfonate and polyethylene glycol, etc.

[0045] Preferably, based on the total mass of the MHP product as 100wt%, the Mg content in the MHP product is ≤2.6wt%, for example, it can be 2.6wt%, 2.4wt%, 2.2wt%, 2.0wt%, 1.8wt%, 1.5wt%, or 1.3wt%, etc.

[0046] Preferably, based on the total mass of the MHP product as 100wt%, the Mn content in the MHP product is 3.3 to 10wt%, for example, it can be 3.3wt%, 3.5wt%, 4wt%, 4.5wt%, 5wt%, 5.5wt%, 6wt%, 6.5wt%, 7wt%, 7.5wt%, 8wt%, 8.5wt%, 9wt%, 9.5wt%, or 10wt%, etc.

[0047] Preferably, the moisture content of the MHP product is ≤47.5%, for example, it can be 47.5%, 47.0%, 46.5%, 46.0%, 45.5%, 45%, 43.5%, 43%, 42.5%, 42%, or 41.5%, etc.

[0048] As a further preferred technical solution of the present invention, according to Figure 1 The process flow shown is performed, and the method includes the following steps:

[0049] (1) A mixture of laterite nickel ore de-ferroaluminate solution, magnesium precipitant, carbonate precipitant, composite oxidant, and auxiliary precipitant is prepared and subjected to a precipitation reaction at 30–85°C and pH 6.5–7.5 for 0.5–10 h to obtain MHP slurry; the carbonate precipitant is sodium carbonate; the molar ratio of sodium carbonate to magnesium compounds in the magnesium precipitant is (0.0001–5):1; the amount of composite oxidant added is related to the amount of Mn in the laterite nickel ore de-ferroaluminate solution. 2+ All oxidized to Mn 3+ The required molar ratio of the theoretical amount of the composite oxidant is (0.0001~1):1; the molar ratio of the amount of the auxiliary precipitant added to the total amount of nickel and cobalt in the liquid after iron and aluminum removal from the laterite nickel ore is (0.1~0.9):1;

[0050] (2) The MHP slurry in step (1) is thickened, and the thickened underflow is separated into solid and liquid to obtain the MHP product.

[0051] In step (1), the laterite nickel ore solution after iron and aluminum removal contains 2-6 g / L nickel, 0.1-0.6 g / L cobalt, 1-6 g / L manganese, and 4-12 g / L magnesium; the composite oxidant in step (1) includes a primary oxidant and a secondary oxidant; the primary oxidant includes a solid peroxide oxidant and / or a manganese-containing oxidant; the solid peroxide oxidant includes Na2O2 and / or K2O2; the manganese-containing oxidant includes K2MnO4 and / or KMnO4; the secondary oxidant includes NaClO and / or H2O2; and the auxiliary precipitant includes a complexing agent and / or a surfactant.

[0052] The complexing agent includes ethylenediaminetetraacetic acid and / or ammonia; the surfactant includes any one or a combination of at least two of hexadecyltrimethylammonium bromide, sodium dodecylbenzenesulfonate, or polyethylene glycol.

[0053] The preparation method of the magnesium precipitant in step (1) is as follows: a magnesium-containing solution and an alkaline solution with a mass concentration of 0.5-30 wt% are mixed, and an alkaline conversion reaction is carried out at 30-70°C for 2-10 minutes to obtain the magnesium precipitant. The magnesium-containing solution includes the manganese precipitation solution of laterite nickel ore. The amount of alkaline substance added to the alkaline solution is 10 wt% to 100 wt% of the theoretical amount required for all magnesium to precipitate in the magnesium-containing solution. The alkaline solution includes any one or a combination of at least two of sodium carbonate, ammonium carbonate, or sodium hydroxide. The magnesium compound in the magnesium precipitant includes magnesium hydroxide and / or magnesium carbonate.

[0054] Compared with the prior art, the present invention has at least the following beneficial effects:

[0055] (1) The method for preparing MHP using a composite precipitant provided by the present invention involves compounding a magnesium precipitant with sodium carbonate, and utilizing the OH- precipitant slowly released by the magnesium precipitant in the precipitation system. - OH generated by the ionization of sodium carbonate - The synergistic effect regulates the pH of the precipitation system, avoiding local over-alkaliness that leads to poor product quality of MHP. The preferred Ni content is above 40.0 wt%, the preferred Co content is above 3.0 wt%, the preferred Mg content is below 1.5 wt%, and the preferred moisture content is below 43.2%.

[0056] (2) The method for preparing MHP using a composite precipitant provided by the present invention further optimizes the preparation of the composite oxidant with magnesium precipitant and sodium carbonate, and utilizes the composite oxidant to remove Mn from the liquid after iron and aluminum removal from laterite nickel ore. 2+ Oxidation is performed to control the Mn content in MHP products. The Mn content is controllable within the range of 3.3 to 10.0 wt%, which meets the market demand for high-quality MHP products with different Mn contents. Attached Figure Description

[0057] Figure 1 This is a process flow diagram of the method for preparing MHP using composite precipitants provided by the present invention. Detailed Implementation

[0058] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments. However, the following examples are merely simplified examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention is determined by the claims.

[0059] I. Implementation Examples

[0060] Example 1

[0061] This embodiment provides a method for preparing MHP using a composite precipitant, the method comprising the following steps:

[0062] (1) A mixture of laterite nickel ore de-ferroaluminate solution (containing 4 g / L nickel, 0.3 g / L cobalt, 3 g / L manganese and 8 g / L magnesium), magnesium precipitant, sodium carbonate, Na2O2, K2MnO4, hydrogen peroxide (10 wt%) and ethylenediaminetetraacetic acid (EDTA) was prepared and subjected to a precipitation reaction at 50 °C and pH 7.0 for 6 h to obtain MHP slurry; the molar ratio of sodium carbonate to magnesium compounds in the magnesium precipitant was 3:1; the mass ratio of Na2O2, K2MnO4 and H2O2 in the hydrogen peroxide was 1:1:0.4, and the sum of the amounts of Na2O2, K2MnO4 and hydrogen peroxide added was equal to the amount of Mn in the laterite nickel ore de-ferroaluminate solution. 2+ All oxidized to Mn 3+The required theoretical molar ratio of the composite oxidant is 0.0005:1; the molar ratio of the amount of ethylenediaminetetraacetic acid added to the total amount of nickel and cobalt in the liquid after iron and aluminum removal from laterite nickel ore is 0.5:1.

[0063] (2) The MHP slurry in step (1) is thickened and filtered to obtain a thick underflow, and then pressure filtered to obtain the MHP product.

[0064] The preparation method of the magnesium precipitant in step (1) is as follows: mix the manganese precipitation liquid of lateritic nickel ore (magnesium concentration of 5 g / L) and sodium hydroxide solution with a mass concentration of 15 wt%, and carry out the alkali conversion reaction at 50°C for 8 min to obtain the magnesium precipitant (wherein the magnesium compound is magnesium hydroxide), and the sodium hydroxide in the sodium hydroxide solution is 50 wt% of the theoretical amount required to precipitate all the magnesium in the manganese precipitation liquid of lateritic nickel ore.

[0065] Example 2

[0066] This embodiment provides a method for preparing MHP using a composite precipitant, the method comprising the following steps:

[0067] (1) A mixture of laterite nickel ore solution after iron and aluminum removal (containing 2 g / L nickel, 0.1 g / L cobalt, 1 g / L manganese and 4 g / L magnesium), magnesium precipitant, sodium carbonate, K2O2, KMnO4, NaClO and ammonia water was subjected to a precipitation reaction at 40℃ and pH 6.5 for 10 h to obtain MHP slurry; the molar ratio of sodium carbonate to magnesium compounds in the magnesium precipitant was 1:1; the mass ratio of K2O2, KMnO4 and NaClO was 1:1:0.2, and the sum of the amounts of K2O2, KMnO4 and NaClO added was equal to the amount of MnO in the laterite nickel ore solution after iron and aluminum removal. 2+ All oxidized to Mn 3+ The required theoretical molar ratio of the composite oxidant is 0.0001:1; the molar ratio of the amount of ammonia added to the total amount of nickel and cobalt in the liquid after iron and aluminum removal from laterite nickel ore is 0.1:1.

[0068] (2) The MHP slurry in step (1) is thickened and filtered to obtain a thick underflow, and then pressure filtered to obtain the MHP product.

[0069] The preparation method of the magnesium precipitant in step (1) is as follows: mix the manganese precipitation liquid of lateritic nickel ore (magnesium concentration of 4 g / L) and sodium carbonate solution with a mass concentration of 8 wt%, and carry out the alkali conversion reaction at 30°C for 10 min to obtain the magnesium precipitant (wherein the magnesium compound is magnesium carbonate), and the sodium carbonate in the sodium carbonate solution is 40 wt% of the theoretical amount required to precipitate all the magnesium in the manganese precipitation liquid of lateritic nickel ore.

[0070] Example 3

[0071] This embodiment provides a method for preparing MHP using a composite precipitant, the method comprising the following steps:

[0072] (1) A mixture of laterite nickel ore de-ferroaluminate solution (containing 6 g / L nickel, 0.6 g / L cobalt, 6 g / L manganese and 12 g / L magnesium), magnesium precipitant, sodium carbonate, Na2O2, KMnO4, hydrogen peroxide (30 wt%) and ethylenediaminetetraacetic acid (EDTA) was prepared and subjected to a precipitation reaction at 70 °C and pH 7.5 for 3 h to obtain MHP slurry; the molar ratio of sodium carbonate to magnesium compounds in the magnesium precipitant was 5:1; the mass ratio of Na2O2, KMnO4 and H2O2 in the hydrogen peroxide was 1:1:0.6, and the sum of the amounts of Na2O2, KMnO4 and hydrogen peroxide added was equal to the amount of Mn in the laterite nickel ore de-ferroaluminate solution. 2+ All oxidized to Mn 3+ The required theoretical molar ratio of the composite oxidant is 0.001:1; the molar ratio of the amount of ethylenediaminetetraacetic acid added to the total amount of nickel and cobalt in the liquid after iron and aluminum removal from laterite nickel ore is 0.9:1.

[0073] (2) The MHP slurry in step (1) is thickened and filtered to obtain a thick underflow, and then pressure filtered to obtain the MHP product.

[0074] The preparation method of the magnesium precipitant in step (1) is as follows: mix the manganese precipitation liquid of lateritic nickel ore (magnesium concentration of 6 g / L) and the ammonium carbonate solution with a mass concentration of 30 wt%, and carry out the alkali conversion reaction at 70°C for 2 min to obtain the magnesium precipitant (wherein the magnesium compound is magnesium carbonate), and the ammonium carbonate in the ammonium carbonate solution is 60 wt% of the theoretical amount required to precipitate all the magnesium in the manganese precipitation liquid of lateritic nickel ore.

[0075] Example 4

[0076] This embodiment provides a method for preparing MHP using a composite precipitant. Except for step (1), where the molar ratio of sodium carbonate to magnesium compound in the magnesium precipitant is 0.05:1, the method is the same as in Example 1.

[0077] Example 5

[0078] This embodiment provides a method for preparing MHP using a composite precipitant. Except for step (1), where the molar ratio of sodium carbonate to magnesium compound in the magnesium precipitant is 5.2:1, the method is the same as in Example 1.

[0079] Example 6

[0080] This embodiment provides a method for preparing MHP using a composite precipitant. Except for step (1) where K2MnO4 is not added, and the amount of Na2O2 and hydrogen peroxide added is the same as the total amount of Na2O2, K2MnO4 and hydrogen peroxide added in Example 1, the method is otherwise the same as in Example 1.

[0081] Example 7

[0082] This embodiment provides a method for preparing MHP using a composite precipitant. Except for step (1) where hydrogen peroxide (10 wt%) is not added, and the amount of Na2O2 and K2MnO4 added is the same as the total amount of Na2O2, K2MnO4 and hydrogen peroxide added in Example 1, the method is otherwise the same as in Example 1.

[0083] Examples 8 to 11

[0084] Examples 8-11 provide a method for preparing MHP using a composite precipitant, wherein the method, except for the amount of Na2O2, K2MnO4 and hydrogen peroxide added in step (1) and the amount of Mn in the liquid after iron and aluminum removal from laterite nickel ore, is... 2+ All oxidized to Mn 3+ Except for the required molar ratios of the theoretical amounts of the composite oxidant being 0.0003:1, 0.0008:1, 0.001:1, and 0.0015:1, all other ratios are the same as in Example 1.

[0085] Example 12

[0086] This embodiment provides a method for preparing MHP using a composite precipitant. Except that the magnesium precipitant in step (1) is not prepared by a conversion reaction, but by directly mixing magnesium hydroxide with other raw materials, and the amount of magnesium hydroxide added is the same as the content of magnesium hydroxide in the magnesium precipitant obtained by the conversion reaction, the rest of the method is the same as in Example 1.

[0087] Example 13

[0088] This embodiment provides a method for preparing MHP using a composite precipitant. Except for step (1) where no auxiliary precipitant (ethylenediaminetetraacetic acid) is added, the method is the same as in Example 1.

[0089] II. Comparative Example

[0090] Comparative Example 1

[0091] This comparative example provides a method for preparing MHP using a composite precipitant. The method is the same as in Example 1 except that sodium carbonate is not added in step (1).

[0092] Comparative Example 2

[0093] This comparative example provides a method for preparing MHP using a composite precipitant. The method is the same as in Example 1 except that sodium carbonate is replaced with sodium hydroxide in step (1).

[0094] III. Tests and Results

[0095] The Ni content, Co content, Mg content, Mn content, and moisture content of the MHP products prepared by the methods described in the above embodiments or comparative examples are shown in Table 1.

[0096] Table 1

[0097]

[0098]

[0099] The data in Table 1 shows that:

[0100] (1) As can be seen from Examples 1 to 3, the method for preparing MHP with composite precipitant provided by the present invention successfully prepares high-quality MHP products by compounding the magnesium precipitant, carbonate precipitant, composite oxidant and auxiliary precipitant. The Ni content is as high as 40.0 wt% or more, the Co content is as high as 3.0 wt% or more, the Mn content is controllable in the range of 3.3 to 10.0 wt%, the Mg content is as low as 1.5 wt% or less, and the moisture content is preferably as low as 43.2% or less, which meets the market demand for high-quality MHP products with different Mn contents.

[0101] (2) As can be seen from Examples 1, 4, and 5, the method of the present invention regulates the C content in the precipitation system by adjusting the molar ratio of sodium carbonate to magnesium compound in the magnesium precipitant in step (1) to (0.0001-5):1. Mg and C OH - This further regulated the precipitation process of nickel, cobalt, manganese, and magnesium, thereby achieving control over the quality of MHP products.

[0102] (3) As can be seen from the combined examples 1 and 6 to 7, the method of the present invention selects to combine the composite oxidant with the magnesium precipitant and sodium carbonate, and further preferably the composite oxidant includes a main oxidant and a secondary oxidant, and further preferably the main oxidant is a combination of a solid peroxide oxidant and the manganese-containing oxidant; thus ensuring that nickel and cobalt are fully precipitated while also controlling the precipitation process of Mn, thereby achieving controllable Mn content in MHP products to meet market demand for MHP products with different Mn contents.

[0103] (4) It can be seen from the combined examples 1 and 8 to 11 that the Mn content in the MHP products obtained in examples 1 and 8 to 11 is 7.5wt%, 6.5wt%, 8.5wt%, 10.0wt%, and 10.5wt%, respectively. This shows that the present invention can flexibly adjust the Mn content in the MHP product by adjusting the amount of the composite oxidant added, and can adapt to different product requirements.

[0104] (5) As can be seen from the combined examples 1 and 12 to 13, the method of the present invention, through further optimization of the use of a alkali conversion reaction, produces a magnesium precipitate containing free OH groups. - This is beneficial for the precipitation reaction; and further optimization by adding an auxiliary precipitant is also beneficial for the precipitation reaction, further improving the quality of MHP products.

[0105] (6) As can be seen from the combined example 1 and comparative examples 1 and 2, the present invention selects sodium carbonate as a carbonate precipitant and combines it with the magnesium precipitant. The two work synergistically to precisely control the pH of the precipitation system, effectively avoid the problem of local over-alkaliness, and obtain a high-quality MHP product.

[0106] The applicant declares that the above description is only a specific embodiment 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 conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A method for preparing MHP using a composite precipitant, characterized in that, The method includes the following steps: (1) Mix laterite nickel ore after iron and aluminum removal liquid, magnesium precipitant, composite oxidant and carbonate precipitant to carry out precipitation reaction to obtain MHP slurry; the carbonate precipitant is sodium carbonate; the molar ratio of sodium carbonate to magnesium compound in the magnesium precipitant is (1~5):1; The composite oxidant includes a primary oxidant and a secondary oxidant; the primary oxidant is a combination of a solid peroxide oxidant and a manganese-containing oxidant; the solid peroxide oxidant includes Na2O2 and / or K2O2; the manganese-containing oxidant includes K2MnO4 and / or KMnO4; and the secondary oxidant includes NaClO and / or H2O2. The amount of the composite oxidant added is related to the amount of Mn in the liquid after iron and aluminum removal from the laterite nickel ore. 2+ All oxidized to Mn 3+ The required molar ratio of the theoretical amount of the composite oxidant is (0.0001~0.0015):1; (2) The MHP slurry in step (1) is thickened, and the thickened underflow is separated into solid and liquid to obtain the MHP product.

2. The method according to claim 1, characterized in that, The liquid from the laterite nickel ore in step (1) after removing iron and aluminum contains nickel, cobalt, manganese and magnesium.

3. The 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 2~6 g / L nickel, 0.1~0.6 g / L cobalt, 1~6 g / L manganese and 4~12 g / L magnesium.

4. The method according to claim 1, characterized in that, The magnesium compounds in the magnesium precipitant in step (1) include magnesium hydroxide and / or magnesium carbonate.

5. The method according to claim 1, characterized in that, The magnesium precipitant in step (1) is obtained by mixing a magnesium-containing solution and an alkaline solution to undergo an alkaline conversion reaction.

6. The method according to claim 5, characterized in that, The magnesium-containing solution includes the manganese-precipitated solution from laterite nickel ore.

7. The method according to claim 5, characterized in that, The alkaline solution includes any one or a combination of at least two of sodium carbonate, ammonium carbonate, or sodium hydroxide.

8. The method according to claim 5, characterized in that, The mass concentration of the alkaline solution is 0.5~30wt%.

9. The method according to claim 5, characterized in that, The amount of alkaline substance added to the alkaline solution is 10wt% to 100wt% of the theoretical amount required for complete precipitation of magnesium in the magnesium-containing solution.

10. The method according to claim 9, characterized in that, The amount of alkaline substance added to the alkaline solution is 50wt% to 60wt% of the theoretical amount required for complete precipitation of magnesium in the magnesium-containing solution.

11. The method according to claim 5, characterized in that, The temperature for the alkali conversion reaction is 30~70℃.

12. The method according to claim 5, characterized in that, The time for the alkali conversion reaction is 2 min to 10 min.

13. The method according to claim 1, characterized in that, The precipitation reaction in step (1) is carried out at a temperature of 30~85℃.

14. The method according to claim 1, characterized in that, The precipitation reaction in step (1) takes 1 to 8 hours.

15. The method according to claim 14, characterized in that, The precipitation reaction in step (1) takes 2 to 6 hours.

16. The method according to claim 1, characterized in that, The pH of the precipitation reaction in step (1) is 6.8~7.

5.

17. The method according to claim 1, characterized in that, The mixing in step (1) also includes the addition of an auxiliary precipitant.

18. The method according to claim 17, characterized in that, The molar ratio of the amount of the auxiliary precipitant added to the total amount of nickel and cobalt in the liquid after iron and aluminum removal from the laterite nickel ore is (0.1~0.9):

1.

19. The method according to claim 17, characterized in that, The auxiliary precipitant includes a complexing agent and / or a surfactant.

20. The method according to claim 19, characterized in that, The complexing agent includes ethylenediaminetetraacetic acid and / or ammonia.

21. The method according to claim 19, characterized in that, The surfactant includes any one or a combination of at least two of hexadecyltrimethylammonium bromide, sodium dodecylbenzenesulfonate, or polyethylene glycol.

22. The method according to claim 1, characterized in that, Based on a total mass of 100wt% of the MHP product, the Mg content in the MHP product is ≤2.3wt%.

23. The method according to claim 1, characterized in that, Based on a total mass of 100wt% for the MHP product, the Mn content in the MHP product is 3.3~10wt%.

24. The method according to claim 1, characterized in that, The moisture content of the MHP product is ≤45.2%.

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