Method for preparing MHP from composite precipitant

Abstract

The invention relates to a method for preparing MHP by using a composite precipitator. The method comprises the following steps: firstly, mixing the laterite-nickel ore iron and aluminum removed liquid, a magnesium precipitator and bicarbonate for precipitation reaction to obtain MHP slurry; the bicarbonate is ammonium bicarbonate; the MHP slurry is subjected to thickening treatment, obtained thick underflow is subjected to solid-liquid separation, and an MHP product is obtained; according to the method, the content proportion of nickel, cobalt and manganese in an MHP product is regulated and controlled by controlling the crystallization process of the MHP, the content of Ni is preferably as high as 38.0 wt% or above, the content of Co is preferably as high as 1.4 wt% or above, the content of Mn is controllable in the range of 3.0-9.5 wt%, meanwhile, the content of Mg is reduced to 1.4 wt% or below, the content of water is preferably as low as 43.0% or below, and the content of Co is preferably as low as 9.0% or below. And high-quality MHP products with different Mn contents are obtained.

Description

Technical Field

[0001] The invention relates to the technical field of hydrometallurgy, in particular to a method for preparing MHP using a composite precipitant. Background Art

[0002] Nickel cobalt hydroxide (MHP) is an intermediate product in the hydrometallurgical process of laterite nickel ore. It is an important raw material for cathode materials in lithium-ion batteries and nickel-cobalt-manganese (NCM) batteries. It can also be used to produce products such as nickel sulfate, refined nickel cobalt hydroxide, and nickel plate, and has promising application prospects. Currently, methods for producing MHP in the hydrometallurgical process of laterite nickel ore mainly include seed growth and direct precipitation reaction. However, existing seed growth processes generally require recycling approximately 90% of the seed crystals for regrowth, resulting in only about 10% growth each time. This long seed growth process leads to low production efficiency. Existing direct precipitation methods for producing MHP products are also prone to localized overalkalinity (i.e., excessively high pH in the aqueous solution). This leads to the simultaneous precipitation of multiple metal ions (primarily nickel, cobalt, magnesium, and manganese) in the precipitation system, resulting in poor quality of the resulting MHP precipitate, high levels of impurities, and a high water content. Therefore, researchers are committed to developing high-quality MHP products that meet market demand.

[0003] For example, CN119571083A discloses a method for precipitating nickel and cobalt from a nickel-cobalt solution and a nickel-cobalt hydroxide product. This method uses a seed crystal growth process that requires pretreatment of the seed crystals and multiple cycles of growth, which is time-consuming and has low production efficiency. In addition, the nickel-cobalt hydroxide product obtained by this method has a high Mg content and water content, and a narrow controllable range of Mn, which cannot meet the market demand for MHP products with different Mn contents.

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

[0005] In view of this, how to provide a method for preparing MHP with a composite precipitant to solve the problems of low production efficiency of MHP prepared by the traditional seed crystal growth process and the existing direct precipitation reaction that easily leads to local over-alkalinity, resulting in uneven ratios of nickel, cobalt and manganese elements in the product, high magnesium content and water content, so as to obtain high-quality MHP products, is an urgent problem to be solved in this field. Summary of the Invention

[0006] To solve the above technical problems, the present invention provides a method for preparing MHP using a composite precipitant, which achieves precise control of the MHP crystallization process, thereby achieving control of the nickel, cobalt and manganese content ratio in the MHP product, and reducing its Mg content and moisture content. This avoids the problem of low production efficiency caused by the need for recycled seed growth in the traditional seed growth process for preparing MHP, as well as the problem of local over-alkalinity in the existing non-seed growth process, i.e., the direct precipitation reaction process, which leads to uneven distribution of nickel, cobalt and manganese and high Mg content and moisture content, thereby ultimately obtaining a high-quality MHP product.

[0007] To achieve this object, the present invention adopts the following technical solutions:

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

[0009] (1) mixing a laterite nickel ore solution after iron and aluminum removal, a magnesium precipitant, and a bicarbonate to perform a precipitation reaction to obtain an MHP slurry; the bicarbonate is ammonium bicarbonate;

[0010] (2) The MHP slurry in step (1) is subjected to a thickening treatment, and the obtained thick bottom flow is subjected to solid-liquid separation to obtain the MHP product.

[0011] The method of the present invention is to compound a magnesium precipitant with bicarbonate, and select ammonium bicarbonate as the bicarbonate, and utilize the OH released by the magnesium precipitant in the precipitation system to - The ammonium bicarbonate ionizes slowly to produce OH - The synergistic effect can regulate the pH of the precipitation system during the entire precipitation reaction process, which is more conducive to avoiding the occurrence of local over-alkalinity, thereby obtaining high-quality MHP products. Compared with the traditional precipitation system of directly adding sodium hydroxide solution, it effectively avoids the occurrence of local over-alkalinity problems, avoids the precipitation of a large amount of magnesium ions, and makes the precipitated grains more uniform, and the water content is also reduced accordingly. Compared with the traditional method of preparing MHP products by seed crystal growth process, it avoids the problem of low production efficiency caused by the need for recycled seed crystal growth, thereby saving production costs.

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

[0013] Preferably, the laterite nickel ore liquid after iron and aluminum removal in step (1) comprises 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, 2-6 g / L nickel can be, for example, 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; 0.1-0.6 g / L cobalt can be, for example, 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; 1-6 g / L manganese can be, for example, 1.0 g / L, 1. 4g / L, 1.8g / L, 2.2g / L, 2.6g / L, 3.0g / L, 3.4g / L, 3.8g / L, 4.0g / L, 4.4g / L, 4.8g / L, 5.2g / L, 5.6g / L or 6.0g / L, etc.; 4-12g / L magnesium, for example, can be 4g / L, 5g / L, 6g / L, 7g / L, 8g / L, 9g / L, 10g / L, 11g / L or 12g / 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 the ammonium bicarbonate in step (1) to the magnesium compound in the 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, in the present invention, the pH of the precipitation system is ensured to be 6.5-7.5 by regulating the molar ratio of the ammonium bicarbonate in step (1) to the magnesium compound in the magnesium precipitant to (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 carry out a alkali conversion reaction.

[0019] Preferably, the magnesium-containing solution comprises the liquid after manganese precipitation of laterite nickel ore.

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

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

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

[0023] Preferably, the amount of alkaline substance added to the alkaline solution is 10wt% to 100wt% of the theoretical amount required for all 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-transfer reaction is 30-70°C, for example, 30°C, 35°C, 40°C, 45°C, 50°C, 55°C, 60°C, 65°C or 70°C.

[0025] Preferably, the time of the base transfer reaction is 2 min to 10 min, for example, 2 min, 4 min, 6 min, 8 min or 10 min.

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

[0027] The present invention further adds a composite oxidant, and uses the composite oxidant to remove the iron and aluminum from the laterite nickel ore. 2+ Oxidized to Mn 3+ , to promote the precipitation of manganese ions, thereby further increasing the Mn content in the MHP product. By further regulating the amount of the composite oxidant added, the Mn content in the MHP product can be regulated, thereby meeting the market demand for MHP products with different Mn contents.

[0028] The present invention further preferably comprises the step (1) wherein the mixing further comprises the addition of a composite oxidant. Advantages of the composite oxidation include the rapid formation of some high-valent manganese oxides in the early stage of the precipitation reaction, providing nucleation and crystallization sites for MHP, thereby improving the problems 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, and solving the problem that manganese is oxidized into colloidal MnOOH and amorphous manganese dioxide due to the difficulty in controlling the process conditions in a simple air oxidation process, resulting in the MHP product being easily entrained with impurities, having a high water content and being difficult to filter.

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

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

[0031] Among them, the present invention further preferably comprises a combination of a solid peroxide oxidant and a manganese-containing oxidant, wherein sodium hydroxide and hydrogen peroxide generated by the reaction of peroxide with water are used to oxidize Mn. 2+ At the same time, OH - To precipitate manganese and nickel-cobalt ions; and further oxidize Mn using the manganese-containing oxidant 2+ , and the MnO2 formed after its reduction can provide the crystal nuclei required for the precipitation of nickel and cobalt ions. The two work synergistically to increase the ratio of nickel, cobalt and manganese in the MHP product.

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

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

[0034] Preferably, the secondary oxidant comprises 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 the composite oxidant added in step (1) is equal to the amount of Mn in the laterite nickel ore after iron and aluminum removal. 2+ All oxidized to Mn 3+ The molar ratio of the theoretical amount of the composite oxidant required is (0.0001-1):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 (0.0001-0.001:1).

[0037] Preferably, the temperature of the precipitation reaction in step (1) is 30-85°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, it can be 0.5 hours, 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, 7 hours or 8 hours, etc., preferably 2 to 6 hours.

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

[0040] Preferably, the mixing in step (1) further comprises adding 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 laterite nickel ore after iron and aluminum removal is (0.1-0.9):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 comprises a complexing agent and / or a surfactant.

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

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

[0045] Preferably, based on the total mass of the MHP product being 100 wt%, the Mg content in the MHP product is ≤ 2.4 wt%, for example, it may be 2.4 wt%, 2.2 wt%, 2.0 wt%, 1.8 wt%, 1.5 wt%, 1.3 wt% or 1.1 wt%.

[0046] Preferably, based on the total mass of the MHP product as 100wt%, the Mn content in the MHP product is 3.0-9.5wt%, for example, 3.0wt%, 4.0wt%, 5.0wt%, 6.0wt%, 7.0wt%, 8.0wt%, 9.0wt% or 9.5wt%.

[0047] Preferably, the moisture content of the MHP product is ≤47.0%, for example, it can be 47.0%, 46.5%, 46.0%, 45.5%, 45.0%, 44.5%, 44.0%, 43.5%, 43.0%, 42.5%, 42.0%, 41.5%, 41.0% or 40.5%.

[0048] As a further preferred technical solution of the present invention, according to Figure 1 The process flow shown in FIG. 1 is carried out, and the method comprises the following steps:

[0049] (1) mixing a laterite nickel ore solution after iron and aluminum removal, a magnesium precipitant, a bicarbonate, a composite oxidant and an auxiliary precipitant, and performing a precipitation reaction at 30-85° C. and a pH of 6.5-7.5 for 0.5-10 h to obtain an MHP slurry; the bicarbonate is ammonium bicarbonate; the molar ratio of the ammonium bicarbonate to the magnesium compound in the magnesium precipitant is (0.0001-5):1; the amount of the composite oxidant added is the same as the amount of Mn in the laterite nickel ore solution after iron and aluminum removal. 2+ All oxidized to Mn 3+ The molar ratio of the theoretical amount of the required 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 laterite nickel ore after iron and aluminum removal is (0.1-0.9):1;

[0050] (2) The MHP slurry in step (1) is subjected to a thickening treatment, and the obtained thick bottom flow is subjected to solid-liquid separation to obtain the MHP product;

[0051] Wherein, the laterite nickel ore liquid after iron and aluminum removal in step (1) comprises 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) comprises a main oxidant and a secondary oxidant; the main oxidant comprises a solid peroxide oxidant and / or a manganese-containing oxidant; the solid peroxide oxidant comprises Na2O2 and / or K2O2; the manganese-containing oxidant comprises K2MnO4 and / or KMnO4; the secondary oxidant comprises NaClO and / or H2O2; the auxiliary precipitant comprises a complexing agent and / or a surfactant;

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

[0053] The preparation method of the magnesium precipitant in step (1) comprises: mixing a magnesium-containing solution and an alkaline solution with a mass concentration of 0.5 to 30 wt%, and performing a alkali conversion reaction at 30 to 70° C. for 2 to 10 minutes to obtain the magnesium precipitant, wherein the magnesium-containing solution comprises a solution after manganese precipitation from laterite nickel ore; the amount of alkaline substance added to the alkaline solution is 10 to 100 wt% of the theoretical amount required for all magnesium precipitation in the magnesium-containing solution; the alkaline solution comprises any one or a combination of at least two of ammonium bicarbonate, ammonium carbonate or sodium hydroxide; and the magnesium compound in the magnesium precipitant comprises 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 with a composite precipitant provided by the present invention comprises compounding a magnesium precipitant with ammonium bicarbonate, and utilizing the OH released by the magnesium precipitant in the precipitation system. - The ammonium bicarbonate ionizes slowly to produce OH - The pH of the precipitation system is regulated synergistically throughout the precipitation reaction process to avoid the problem of poor quality of the MHP product caused by local over-alkalinity, so that the Ni content is preferably as high as 38.0wt% or more, the Co content is preferably as high as 3.0wt% or more, the Mg content is reduced to 1.4wt% or more, and the water content is preferably as low as 43.0% or less.

[0056] (2) The method for preparing MHP with the composite precipitant provided by the present invention is further preferably compounded with the composite oxidant, a magnesium precipitant and ammonium bicarbonate, and using the composite oxidant to remove Mn in the laterite nickel ore after iron and aluminum removal. 2+ Oxidation is performed to achieve regulation of the Mn content in the MHP product. Mn is controllable within the range of 3.0 to 9.5 wt%, meeting the market demand for high-quality MHP products with different Mn contents. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] Figure 1 The figure is a process flow chart of the method for preparing MHP using the composite precipitant provided by the present invention. DETAILED DESCRIPTION

[0058] The technical solution of the present invention will be further described below with reference to the accompanying drawings and through 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 shall be subject to the claims.

[0059] 1. Implementation

[0060] Example 1

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

[0062] (1) mixing a laterite nickel ore de-ironized and aluminum-removed liquid (comprising 4 g / L nickel, 0.3 g / L cobalt, 3 g / L manganese and 8 g / L magnesium), a magnesium precipitant, ammonium bicarbonate, Na2O2, K2MnO4, hydrogen peroxide (12 wt%) and ethylenediaminetetraacetic acid, and carrying out a precipitation reaction at 50° C. and pH 7.0 for 6 h to obtain an MHP slurry; the molar ratio of the ammonium bicarbonate to the magnesium compound in the magnesium precipitant is 3:1; the mass ratio of the Na2O2, K2MnO4 and H2O2 in the hydrogen peroxide is 1:1:0.5, and the sum of the added amounts of the Na2O2, K2MnO4 and hydrogen peroxide is equal to the amount of Mn in the laterite nickel ore de-ironized and aluminum-removed liquid. 2+ All oxidized to Mn3+ The molar ratio of the theoretical amount of the composite oxidant required is 0.0005:1; the molar ratio of the amount of ethylenediaminetetraacetic acid added to the total amount of nickel and cobalt in the laterite nickel ore after iron and aluminum removal is 0.5:1;

[0063] (2) The MHP slurry in step (1) is concentrated and filtered to obtain a concentrated underflow, which is then filtered to obtain the MHP product;

[0064] The magnesium precipitant of step (1) is prepared by mixing a solution obtained after manganese precipitation of laterite nickel ore (with a magnesium concentration of 5 g / L) and a sodium hydroxide solution having a mass concentration of 15 wt%, and performing a base conversion reaction at 50° C. for 8 min to obtain the magnesium precipitant (wherein the magnesium compound is magnesium hydroxide), wherein the sodium hydroxide in the sodium hydroxide solution is 50 wt% of the theoretical amount required for the complete precipitation of magnesium in the solution obtained after manganese precipitation of laterite 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) mixing a laterite nickel ore de-ironized and de-aluminized solution (comprising 2 g / L nickel, 0.1 g / L cobalt, 1 g / L manganese and 4 g / L magnesium), a magnesium precipitant, ammonium bicarbonate, K2O2, KMnO4, NaClO and aqueous ammonia, and performing a precipitation reaction at 40°C and pH 6.5 for 10 hours to obtain an MHP slurry; the molar ratio of the ammonium bicarbonate to the magnesium compound in the magnesium precipitant is 1:1; the mass ratio of the K2O2, KMnO4 and NaClO is 1:1:0.2, and the sum of the added amounts of the K2O2, KMnO4 and NaClO is equal to the Mn content in the laterite nickel ore de-ironized and de-aluminized solution. 2+ All oxidized to Mn 3+ The molar ratio of the theoretical amount of the required 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 laterite nickel ore after iron and aluminum removal is 0.1:1;

[0068] (2) The MHP slurry in step (1) is concentrated and filtered to obtain a concentrated underflow, which is then filtered to obtain the MHP product;

[0069] The preparation method of the magnesium precipitant in step (1) is as follows: mixing a liquid obtained after manganese precipitation of laterite nickel ore (with a magnesium concentration of 4 g / L) and a sodium carbonate solution with a mass concentration of 8 wt%, and performing a base 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 for the complete precipitation of magnesium in the liquid obtained after manganese precipitation of laterite 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) mixing a laterite nickel ore de-ironized and aluminum-removed liquid (comprising 6 g / L nickel, 0.6 g / L cobalt, 6 g / L manganese and 12 g / L magnesium), a magnesium precipitant, ammonium bicarbonate, Na2O2, KMnO4, hydrogen peroxide (30 wt%) and sodium dodecylbenzene sulfonate, and carrying out a precipitation reaction at 70° C. and a pH of 7.5 for 3 h to obtain an MHP slurry; the molar ratio of the ammonium bicarbonate to the magnesium compound in the magnesium precipitant is 5:1; the mass ratio of the Na2O2, KMnO4 and H2O2 in the hydrogen peroxide is 1:1:0.6, and the sum of the added amounts of the Na2O2, KMnO4 and hydrogen peroxide is equal to the amount of Mn in the laterite nickel ore de-ironized and aluminum-removed liquid. 2+ All oxidized to Mn 3+ The molar ratio of the theoretical amount of the composite oxidant required is 0.001:1; the molar ratio of the amount of sodium dodecylbenzenesulfonate added to the total amount of nickel and cobalt in the laterite nickel ore after iron and aluminum removal is 0.9:1;

[0073] (2) The MHP slurry in step (1) is concentrated and filtered to obtain a concentrated underflow, which is then filtered to obtain the MHP product;

[0074] The preparation method of the magnesium precipitant in step (1) is as follows: mixing a liquid obtained after manganese precipitation of laterite nickel ore (with a magnesium concentration of 6 g / L) and an ammonium carbonate solution with a mass concentration of 30 wt%, and performing a base 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 for the complete precipitation of magnesium in the liquid obtained after manganese precipitation of laterite nickel ore.

[0075] Example 4

[0076] This embodiment provides a method for preparing MHP using a composite precipitant. The method is the same as that of Example 1 except that the molar ratio of the ammonium bicarbonate to the magnesium compound in the magnesium precipitant in step (1) is 0.05:1.

[0077] Example 5

[0078] This embodiment provides a method for preparing MHP using a composite precipitant. The method is the same as that of Example 1 except that the molar ratio of the ammonium bicarbonate to the magnesium compound in the magnesium precipitant in step (1) is 5.2:1.

[0079] Example 6

[0080] This embodiment provides a method for preparing MHP using a composite precipitant. The method is the same as that of Example 1 except that K2MnO4 is not added in step (1) and the amounts of Na2O2 and hydrogen peroxide added are the same as the total amounts of Na2O2, K2MnO4 and hydrogen peroxide added in Example 1.

[0081] Example 7

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

[0083] Example 8 to Example 11

[0084] Examples 8 to 11 provide a method for preparing MHP with a composite precipitant. The method is as follows: except that the amount of Na2O2, K2MnO4 and hydrogen peroxide added in step (1) is the same as that of Mn in the laterite nickel ore after iron and aluminum removal. 2+ All oxidized to Mn 3+ The molar ratios of the theoretical amounts of the composite oxidants required are 0.0003:1, 0.0008:1, 0.001:1 and 0.0015:1, respectively, and the rest are the same as in Example 1.

[0085] Real and Real

[0086] Example 12

[0087] This embodiment provides a method for preparing MHP using a composite precipitant. The method is the same as that of Example 1, except that in step (1), the magnesium precipitant is not prepared by a alkali-transfer reaction, but is directly mixed with a hydrogen-containing magnesium solution and other raw materials, and the amount of the hydrogen-containing magnesium solution added is the same as the content of the hydrogen-containing magnesium solution in the magnesium precipitant obtained by the alkali-transfer reaction.

[0088] Example 13

[0089] This embodiment provides a method for preparing MHP using a composite precipitant. The method is the same as that of Example 1 except that the auxiliary precipitant (ethylenediaminetetraacetic acid) is not added in step (1).

[0090] 2. Comparative Example

[0091] Comparative Example 1

[0092] This comparative example provides a method for preparing MHP using a composite precipitant. The method is the same as Example 1 except that ammonium bicarbonate is not added in step (1).

[0093] Comparative Example 2

[0094] This comparative example provides a method for preparing MHP using a composite precipitant. The method is the same as Example 1 except that ammonium bicarbonate in step (1) is replaced by sodium bicarbonate.

[0095] 3. Test and its results

[0096] The Ni content, Co content, Mg content, Mn content and moisture content of the MHP products prepared by the methods described in the above examples or comparative examples are shown in Table 1.

[0097] Table 1

[0098]

[0099]

[0100] From the data in Table 1 we can see that:

[0101] (1) From Examples 1 to 3, it can be seen that the method for preparing MHP using a composite precipitant provided by the present invention successfully prepares a high-quality MHP product by compounding the magnesium precipitant, bicarbonate, composite oxidant and auxiliary precipitant, and selecting ammonium bicarbonate as the bicarbonate. The MHP product has a Ni content of more than 38.0 wt%, a Co content of more than 3.0 wt%, a Mn content controllable within the range of 3.0 to 9.5 wt%, a Mg content as low as less than 1.4 wt%, and a water content preferably as low as less than 43.0%, thereby meeting the market demand for high-quality MHP products with different Mn contents.

[0102] (2) Combining Examples 1, 4 and 5, it can be seen that the method of the present invention regulates the molar ratio of the ammonium bicarbonate in step (1) to the magnesium compound in the magnesium precipitant to be (0.0001-5):1, thereby regulating the C in the precipitation system. Mg and C OH - , further regulating the precipitation process of nickel, cobalt, manganese and magnesium, thereby achieving the regulation of MHP product quality.

[0103] (3) From Example 1 and Examples 6 to 7, it can be seen that the method of the present invention selects to compound a composite oxidant with the magnesium precipitant and ammonium bicarbonate, 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; while ensuring sufficient precipitation of nickel and cobalt, the precipitation process of Mn is also regulated, thereby achieving controllable Mn content in the MHP product to meet market demand for MHP products with different Mn contents.

[0104] (4) From Example 1 and Examples 8 to 11, it can be seen that the Mn contents in the MHP products obtained in Example 1 and Examples 8 to 11 are 6.5 wt%, 5.5 wt%, 8.8 wt%, 9.5 wt%, and 9.8 wt%, 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.

[0105] (5) From the combination of Example 1, Example 12 and Example 13, it can be seen that the method of the present invention further preferably adopts the alkali conversion reaction, and the free OH in the obtained magnesium precipitant is - , which is beneficial to promote the slow release of OH in the magnesium hydroxide - The precipitation reaction begins before the reaction is carried out; and further preferably, an auxiliary precipitant is additionally added, which is beneficial to the precipitation reaction and further improves the quality of the MHP product.

[0106] (6) It can be seen from Example 1, Comparative Examples 1 and 2 that the present invention uses ammonium bicarbonate as the bicarbonate salt and compounds it with the magnesium precipitant. The two work synergistically to accurately control the pH of the precipitation system, which is more conducive to effectively avoiding the problem of local over-alkalinity and obtaining a high-quality MHP product.

[0107] 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 using a composite precipitant, characterized in that: The method comprises the following steps: (1) mixing a laterite nickel ore solution after iron and aluminum removal, a magnesium precipitant, and a bicarbonate to perform a precipitation reaction to obtain an MHP slurry; the bicarbonate is ammonium bicarbonate; (2) The MHP slurry in step (1) is subjected to a thickening treatment, and the obtained thick bottom flow is subjected to solid-liquid separation to obtain the MHP product.

2. The method according to claim 1, characterized in that The laterite nickel ore liquid after iron and aluminum removal in step (1) contains nickel, cobalt, manganese and magnesium; Preferably, the laterite nickel ore liquid after iron and aluminum removal in step (1) comprises 2-6 g / L nickel, 0.1-0.6 g / L cobalt, 1-6 g / L manganese and 4-12 g / L magnesium.

3. The method according to claim 1 or 2, characterized in that The magnesium compound in the magnesium precipitant in step (1) includes magnesium hydroxide and / or magnesium carbonate; Preferably, the molar ratio of the ammonium bicarbonate in step (1) to the magnesium compound in the magnesium precipitant is (0.0001-5):

1.

4. The method according to any one of claims 1 to 3, characterized in that The magnesium precipitant in step (1) is obtained by mixing a magnesium-containing solution and an alkaline solution to perform a alkali conversion reaction; Preferably, the magnesium-containing solution comprises a solution obtained after manganese precipitation in laterite nickel ore; Preferably, the alkaline solution comprises any one of ammonium bicarbonate, ammonium carbonate or sodium hydroxide, or a combination of at least two of them.

5. The method according to claim 4, characterized in that The mass concentration of the alkaline solution is 0.5 to 30 wt%; Preferably, the amount of alkaline substance added to the alkaline solution is 10 wt% to 100 wt% of the theoretical amount required for all precipitation of magnesium in the magnesium-containing solution, preferably 50 wt% to 60 wt%.

6. The method according to claim 4 or 5, characterized in that The temperature of the alkali conversion reaction is 30 to 70° C. Preferably, the alkali transfer reaction time is 2 min to 10 min.

7. The method according to any one of claims 1 to 6, characterized in that The mixing in step (1) further comprises adding a composite oxidant; Preferably, the composite oxidant comprises a primary oxidant and a secondary oxidant; Preferably, the primary oxidant comprises a solid peroxide oxidant and / or a manganese-containing oxidant, preferably a combination of a solid peroxide oxidant and the manganese-containing oxidant; Preferably, the solid peroxide oxidant comprises Na2O2 and / or K2O2; Preferably, the manganese-containing oxidant comprises K2MnO4 and / or KMnO4; Preferably, the secondary oxidant comprises NaClO and / or H2O2; Preferably, the amount of the composite oxidant added in step (1) is equal to the amount of Mn in the laterite nickel ore after iron and aluminum removal. 2+ All oxidized to Mn 3+ The molar ratio of the required theoretical amount of the composite oxidant is (0.0001-1):

1.

8. The method according to any one of claims 1 to 7, characterized in that The temperature of the precipitation reaction in step (1) is 30-85° C.; Preferably, the precipitation reaction time in step (1) is 1 to 8 hours, preferably 2 to 6 hours; Preferably, the pH of the precipitation reaction in step (1) is 6.8 to 7.

5.

9. The method according to any one of claims 1 to 8, characterized in that The mixing in step (1) further comprises adding an auxiliary precipitant; Preferably, the molar ratio of the amount of the auxiliary precipitant added to the total amount of nickel and cobalt in the laterite nickel ore after iron and aluminum removal is (0.1-0.9):1; Preferably, the auxiliary precipitant comprises a complexing agent and / or a surfactant; Preferably, the complexing agent comprises ethylenediaminetetraacetic acid and / or ammonia; Preferably, the surfactant includes any one of cetyltrimethylammonium bromide, sodium dodecylbenzenesulfonate or polyethylene glycol, or a combination of at least two thereof.

10. The method according to any one of claims 1 to 9, characterized in that: Based on the total mass of the MHP product being 100 wt%, the Mg content in the MHP product is ≤ 2.4 wt%; Preferably, based on the total mass of the MHP product being 100 wt%, the Mn content in the MHP product is 3.0 to 9.5 wt%; Preferably, the moisture content of the MHP product is ≤47.0%.

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