A method for treating nickel-cobalt hydroxide

Abstract

The invention belongs to the field of hydrometallurgy or chemical technology, and particularly relates to a method for treating nickel-cobalt hydroxide, wherein nickel-cobalt hydroxide is reduced by sulfuric acid to leach nickel, cobalt and other elements, so that the direct yield of nickel-cobalt is greatly improved, and then the leached filtrate is neutralized with nickel-cobalt hydroxide or recycled NiCO3 to reach a certain pH, so that elements such as iron and aluminum are precipitated, and a nickel-cobalt solution and a first-stage iron-aluminum slag are obtained by filtration, thereby realizing the separation of nickel-cobalt and iron-aluminum, and the first-stage iron-aluminum slag is leached by acid leaching and ripening to obtain a desiliconized filtrate, which well solves the problem of excessive silicon content in the solution, and then Na2CO3 is used for two-stage iron-aluminum removal and nickel precipitation to obtain filter residue NiCO3 and filtrate Na2SO4 solution. NiCO3 can be recycled to a first-stage iron-aluminum removal process, and Na2SO4 can be evaporated and crystallized to produce by-products, which can save resources and reduce processing costs.

Description

Technical Field

[0001] The invention belongs to the technical field of hydrometallurgy or chemical engineering, and particularly relates to a method for treating nickel-cobalt hydroxide. Background Art

[0002] Nickel cobalt hydroxide is a kind of product made from laterite nickel ore through high pressure acid leaching technology (HPAL). However, in addition to nickel and cobalt, nickel cobalt hydroxide also contains impurities such as iron, aluminum, manganese, and silicon. The current treatment method for nickel cobalt hydroxide is to slurry and dissolve the nickel cobalt hydroxide material, extract and remove impurities, and purify it for reuse. However, flocculants are often added during the front-end treatment of nickel cobalt hydroxide produced from laterite nickel ore, resulting in a large amount of flocculants in the nickel cobalt hydroxide product; and a large amount of reducing agent sodium pyrosulfite is added in the leaching process of nickel cobalt hydroxide, resulting in too high COD concentration in the pre-extraction liquid, which seriously affects the quality of subsequent products; at the same time, in order to remove iron and aluminum, the pH value of the solution in the impurity removal process will be adjusted to 5.0-5.2 or higher, resulting in a large amount of nickel precipitation and reducing the nickel recovery rate.

[0003] Patent CN110551905A discloses a method for treating nickel-cobalt hydroxide, which mainly carries out aging and reduction leaching processes, and only describes the removal methods of Si, Na, and COD, without removing impurities such as aluminum and iron. In addition, the patent removes silicon at the front end of the nickel-cobalt hydroxide, the amount of material is large, and the removed silica gel is viscous and difficult to filter. Patent CN 112359225A discloses a selective leaching process for crude cobalt hydroxide ore, which uses manganese dioxide for pre-oxidation treatment to avoid the repeated use of reducing agents and oxidizing agents, but it adds sodium pyrosulfite to increase the COD content in the solution, and the resulting solution is a crude solution with a high impurity content.

[0004] Therefore, it is particularly important to propose a new method for treating nickel-cobalt hydroxide. Summary of the invention

[0005] In order to solve the above technical problem or at least partially solve the above technical problem, the present invention provides a method for treating nickel cobalt hydroxide, comprising the following steps:

[0006] The nickel-cobalt hydroxide raw material is sequentially subjected to reduction leaching and a first-stage iron and aluminum removal, and a first-stage iron and aluminum slag and a nickel-cobalt solution are obtained after solid-liquid separation;

[0007] The first stage of iron-aluminum slag is ripened and leached, and the leached liquid is solid-liquid separated to obtain silicon slag and desiliconized filtrate;

[0008] Adding a neutralizing agent to the desiliconization filtrate to perform two-stage iron and aluminum removal, and obtaining two-stage iron and aluminum slag and impurity-removed filtrate after solid-liquid separation;

[0009] The impurity-removed filtrate is subjected to nickel precipitation treatment to obtain filter residue NiCO3 and filtrate Na2SO4 after solid-liquid separation;

[0010] The filter residue NiCO3 is recycled to the first iron and aluminum removal step, and the filtrate Na2SO4 is evaporated and crystallized to obtain the by-product Glauber's salt.

[0011] Further, the reduction leaching comprises the following steps:

[0012] The nickel-cobalt hydroxide raw material is made into slurry, wherein the liquid-solid ratio of the slurry is 6-10:1 and the reaction temperature is 60-90°C;

[0013] Inject concentrated sulfuric acid into the slurry to dissolve the slurry and stir for 0.2-0.5h. The amount of concentrated sulfuric acid added is 600-900kg / t. 干矿料 ;

[0014] Then, dilute sulfuric acid with a concentration of 10-40 wt% is added dropwise to the slurry to adjust the pH to 1.2-2.5, and stirring is continued at 300-800 r / min for 1-2 hours;

[0015] Then, a first reducing agent is added to the slurry, and after reacting for 0.5-1h, the reaction liquid is separated into a solid-liquid state to obtain a filter residue and a filtrate.

[0016] Furthermore, the first reducing agent is any one of H2O2 and SO2 or a mixture of the two, and the first reducing agent usage coefficient: the amount of the first reducing agent / the Mn content of the nickel cobalt hydroxide is 0.2-1 mol / mol.

[0017] Furthermore, the first stage of iron and aluminum removal is specifically:

[0018] Adding a first neutralizing agent to the filtrate separated in the reduction leaching step to adjust the pH to 4.5-5.2;

[0019] Then add an oxidant to the filtrate, and react at 60-90°C and 300-800 r / min for 3-5 hours;

[0020] The oxidized reaction liquid is subjected to solid-liquid separation to obtain a section of iron-aluminum slag and nickel-cobalt solution.

[0021] Furthermore, the first neutralizing agent is a nickel cobalt hydroxide raw material or NiCO3; the first neutralizing agent is prepared into a slurry for use, and the solid content in the slurry is 30-50%;

[0022] The oxidant is air or H2O2; when the oxidant is air, the air flow rate is 50-200 mL / min, and when the oxidant is H2O2, the amount of H2O2 is 1.4 kg / t liquid.

[0023] Furthermore, the first stage of iron-aluminum slag aging and leaching is specifically performed as follows:

[0024] The first-stage iron-aluminum slag is mixed with concentrated sulfuric acid at a concentration of 500-900 kg / t, stirred for 1-3 hours, and then water is added to a liquid-to-solid ratio of 3-10:1, and a second reducing agent is added to reduce at 80-95° C. for 0.3-1 hour.

[0025] Furthermore, the second reducing agent is any one of H2O2 and SO2 or a mixture of the two, and the coefficient of the second reducing agent: the amount of the second reducing agent / the amount of Mn in the nickel-cobalt hydroxide is 0.5-1.5 mol / mol.

[0026] Furthermore, a neutralizing agent is added to the desiliconization filtrate to carry out two-stage iron and aluminum removal: the neutralizing agent is NaCO3, the pH is adjusted to 4.5-5.2, and the reaction time is 3-5h.

[0027] Furthermore, the impurity removal filtrate is subjected to nickel precipitation treatment as follows: a neutralizing agent NaCO3 is added to the impurity removal filtrate, the pH is adjusted to 7-8, and the reaction is carried out at 40-70°C for 2-4h.

[0028] Furthermore, the method also includes extracting the nickel-cobalt solution.

[0029] Beneficial effects of the present invention:

[0030] The present invention reduces nickel cobalt hydroxide with sulfuric acid to leach nickel, cobalt and other elements, so that the direct yield of nickel cobalt is greatly improved, and then the leached filtrate is neutralized with nickel cobalt hydroxide or recycled NiCO3 to reach a certain pH value, so that elements such as iron and aluminum are precipitated, and a nickel cobalt solution and a section of iron aluminum slag are obtained by filtration, thereby realizing the separation of nickel cobalt and iron aluminum. The section of iron aluminum slag is acid-leached, ripened and leached to obtain a desiliconized filtrate, which well solves the problem of excessive silicon content in the solution, and then Na2CO3 is used to perform two-stage iron and aluminum removal and nickel precipitation to obtain filter residue NiCO3 and filtrate Na2SO4 solution. NiCO3 can be recycled to a first-stage iron and aluminum removal process, and Na2SO4 can be evaporated and crystallized to produce by-products, which can save resources and reduce processing costs.

[0031] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures pointed out in the description, claims and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0033] Figure 1 The flowchart of the method for treating nickel-cobalt hydroxide proposed by the present invention is shown;

[0034] Figure 2 A detailed flow chart of the method for treating nickel cobalt hydroxide proposed in an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0035] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0036] The method for treating nickel-cobalt hydroxide proposed by the present invention is to reduce nickel-cobalt hydroxide with sulfuric acid to leach nickel, cobalt and other elements, then use nickel-cobalt hydroxide or reuse NiCO3 to neutralize the leached filtrate to a certain pH, so that elements such as iron and aluminum are precipitated, and obtain nickel-cobalt solution and a first-stage iron-aluminum slag after filtration, thereby achieving the separation of nickel-cobalt and iron-aluminum. The first-stage iron-aluminum slag is acid-leached and ripened to obtain a desiliconized filtrate, and then Na2CO3 is used for two-stage iron-aluminum removal and nickel precipitation to obtain filter residue NiCO3 and filtrate Na2SO4 solution. NiCO3 can be reused in the first-stage iron-aluminum removal process, and Na2SO4 can be evaporated and crystallized to produce by-products.

[0037] The main process is as follows Figure 1 As shown:

[0038] Step 1: performing reduction leaching and a first stage of iron and aluminum removal on the nickel-cobalt hydroxide raw material in sequence, and obtaining a first stage of iron-aluminum slag and a nickel-cobalt solution after solid-liquid separation; the obtained nickel-cobalt solution can be further extracted and separated to obtain nickel and cobalt;

[0039] The reduction leaching process includes the following steps: preparing the nickel-cobalt hydroxide raw material into a slurry, wherein the liquid-to-solid ratio in the slurry is 6-10:1; then injecting concentrated sulfuric acid into the slurry to dissolve the slurry, stirring for 0.2-0.5h, and the amount of concentrated sulfuric acid added is 600-900kg / t 干矿料That is, 600-900kg of concentrated sulfuric acid needs to be added to each ton of nickel cobalt hydroxide raw material; then dilute sulfuric acid with a concentration of 10-40wt% is added dropwise to the slurry, the pH of the slurry is adjusted to 1.2-2.5, and stirring is continued at 300-800r / min for 1-2h; then the first reducing agent is added to the slurry, and after reacting for 0.5-1h, the reaction liquid is separated into solid and liquid to obtain filter residue and filtrate. The first reducing agent can be a single H2O2 or SO2, or a mixture of the two. The first reducing agent coefficient: the amount of the first reducing agent / the Mn content of the nickel cobalt hydroxide is 0.2-1mol / mol, and the temperature during the entire reduction leaching process is 60-90°C.

[0040] The first-stage iron and aluminum removal is specifically as follows: a first neutralizing agent is added to the filtrate separated in the reduction leaching step to adjust the pH to 4.5-5.2; the first neutralizing agent can be a nickel-cobalt hydroxide raw material or NiCO3 needs to be adjusted into a slurry for use, and the solid content in the slurry is 30-50%; an oxidant is then added to the filtrate, and the reaction is carried out at a speed of 300-800r / min for 3-5h at 60-90°C; the reaction liquid is subjected to solid-liquid separation to obtain a first-stage iron-aluminum slag and a nickel-cobalt solution, wherein the oxidant used is air or H2O2; when the oxidant is air, the air flow rate of the air is 50-200mL / min, and when the oxidant is H2O2, the amount of H2O2 used is 1.4kg / t liquid.

[0041] Step 2: Ripening the first section of ferroaluminum slag, separating the leaching liquid into solid and liquid to obtain silicon slag and desiliconization filtrate; specifically: mixing the first section of ferroaluminum slag with concentrated sulfuric acid at a rate of 500-900 kg / t, stirring for 1-3 hours, adding water to a liquid-solid ratio of 3-10:1, adding a second reducing agent and reducing at 80-95°C for 0.3-1 hour; the second reducing agent is any one of H2O2 and SO2 or a mixture of the two, and the second reducing agent coefficient: the amount of the second reducing agent / the Mn content of the nickel cobalt hydroxide is 0.5-1.5 mol / mol.

[0042] Step 3: Add a neutralizing agent to the desiliconization filtrate to perform two-stage iron and aluminum removal, and obtain two-stage iron and aluminum slag and impurity-removed filtrate after solid-liquid separation; the neutralizing agent is NaCO3, the pH is adjusted to 4.5-5.2, and the reaction time is 3-5h.

[0043] Step 4: subjecting the impurity-removing filtrate to nickel precipitation treatment, and obtaining filter residue NiCO3 and filtrate Na2SO4 after solid-liquid separation; specifically, adding neutralizing agent NaCO3 to the impurity-removing filtrate, adjusting the pH to 7-8, and reacting at 40-70°C for 2-4h.

[0044] Step 5: The filter residue NiCO3 is recycled to the first iron and aluminum removal step, and the filtrate Na2SO4 is evaporated and crystallized to obtain the by-product Glauber's salt.

[0045] The following is combined with specific embodiments and Figure 2 The above method and the reaction conditions of each step are described in detail, which mainly includes reduction leaching, primary iron and aluminum removal, aging leaching, secondary iron and aluminum removal and nickel precipitation.

[0046] Example 1

[0047] The method for processing nickel cobalt hydroxide in this embodiment is as follows:

[0048] Reduction leaching: nickel cobalt hydroxide raw material is made into slurry, concentrated sulfuric acid is injected into the slurry to dissolve the slurry, the acid-ore ratio is 800kg / t, stirring for 0.5h, reaction temperature is 80℃, 30wt.% dilute sulfuric acid is added dropwise, pH is adjusted to 1.5, stirring is continued for 1.5h, reducing agent H2O2 is added, the amount of reducing agent / Mn content of nickel cobalt hydroxide is 0.8mol / mol, reaction is continued for 0.5h. After solid-liquid separation, filtrate and filter residue are obtained.

[0049] The leaching rates of various components of nickel-cobalt hydroxide after reduction leaching are shown in Table 1:

[0050] Table 1

[0051]

[0052] One-stage iron and aluminum removal: Add the neutralizing agent nickel-cobalt hydroxide raw material to the filtrate, adjust the pH to 4.8, the reaction temperature is 80°C, the oxidant is air, and the reaction is carried out for 4 hours. After solid-liquid separation, a first-stage iron-aluminum slag and a nickel-cobalt solution are obtained. The components of the nickel-cobalt solution obtained after the first-stage iron and aluminum removal are shown in Table 2:

[0053] Table 2

[0054]

[0055] Ripening leaching: Mix a section of iron-aluminum slag with concentrated sulfuric acid, with an acid-ore ratio of 750kg / t, stir for 2 hours, then add water to a liquid-solid ratio of 7:1, add reducing agent H2O2, with a reducing agent dosage / Mn content of nickel-cobalt hydroxide of 1.5mol / mol, stir for 0.5 hours. Then separate the solid and liquid to obtain silicon slag and desiliconization filtrate.

[0056] The components of the desiliconized filtrate obtained after ripening and leaching are shown in Table 3:

[0057] Table 3

[0058]

[0059] The composition of silicon slag obtained after ripening and leaching is shown in Table 4:

[0060] Table 4

[0061]

[0062] Second stage iron and aluminum removal: add neutralizing agent NaCO3 to the desiliconization filtrate, adjust the pH to 4.8, react for 4 hours, and then separate the solid and liquid to obtain iron and aluminum slag and impurity removal filtrate.

[0063] Nickel precipitation: add neutralizing agent NaCO3 to the impurity removal filtrate, adjust the pH to 7.8, react for 3 hours, and the reaction temperature is 60°C. After solid-liquid separation, filter residue NiCO3 and filtrate Na2SO4 are obtained. The filter residue NiCO3 is reused, and the filtrate Na2SO4 is evaporated and crystallized to obtain the by-product Glauber's salt. The whole test is stirred at 500r / min.

[0064] Example 2

[0065] The difference from Example 1 is that the acid-ore ratio in the reduction leaching step is 600 kg / t, and the other conditions remain unchanged. The leaching rate after reduction leaching is shown in Table 5:

[0066] Table 5

[0067]

[0068] Example 3

[0069] The difference from Example 1 is that the amount of reducing agent / Mn content of nickel-cobalt hydroxide in the reduction leaching step is 0.2 mol / mol, and the other conditions remain unchanged. The leaching rate after reduction leaching is shown in Table 6:

[0070] Table 6

[0071]

[0072]

[0073] Example 4

[0074] The difference from Example 1 is that the acid-ore ratio in the mature leaching step is 500 kg / t, and the other conditions remain unchanged. The components of the desiliconized filtrate obtained after mature leaching are shown in Table 7:

[0075] Table 7

[0076]

[0077] The composition of silicon slag obtained after ripening and leaching is shown in Table 8:

[0078] Table 8

[0079]

[0080] Example 5

[0081] The difference from Example 1 is that the amount of the second reducing agent / the amount of Mn in the nickel-cobalt hydroxide in the ripening leaching step is 1 mol / mol, and the operation is performed under the other conditions unchanged. The components of the desiliconized filtrate obtained after ripening leaching are shown in Table 9:

[0082] Table 9

[0083]

[0084] The composition of the silicon slag obtained after ripening and leaching is shown in Table 10:

[0085] Table 10

[0086]

[0087] Example 6

[0088] The difference from Example 1 is that the pH is adjusted to 5.2 in the first iron and aluminum removal step, and the operation is performed under the other conditions unchanged. The components of the nickel-cobalt solution obtained after the first iron and aluminum removal are shown in Table 11:

[0089] Table 11

[0090]

[0091] Comparative Example 1

[0092] The difference from Example 1 is that the amount of concentrated sulfuric acid used in the reduction leaching step is 400 kg / t, and the other conditions remain unchanged. The leaching rate after reduction leaching is shown in Table 12:

[0093] Table 12

[0094]

[0095] Comparative Example 2

[0096] The difference from Example 1 is that the acid-ore ratio in the mature leaching step is 400 kg / t, and the other conditions remain unchanged. The components of the desiliconized filtrate obtained after mature leaching are shown in Table 13:

[0097] Table 13

[0098]

[0099] The composition of the silicon slag obtained after ripening and leaching is shown in Table 14:

[0100] Table 14

[0101]

[0102] Comparative Example 3

[0103] The difference from Example 1 is that the amount of the second reducing agent / the amount of Mn in the nickel-cobalt hydroxide in the ripening leaching step is 0.2 mol / mol, and the other conditions remain unchanged. The components of the desiliconized filtrate obtained after ripening leaching are shown in Table 15:

[0104] Table 15

[0105]

[0106] The composition of the silicon slag obtained after ripening and leaching is shown in Table 16:

[0107] Table 16

[0108]

[0109] Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent substitutions for some of the technical features therein; and these modifications or substitutions do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for treating nickel cobalt hydroxide, characterized in that: The following steps are involved: The nickel-cobalt hydroxide raw material is subjected to reduction leaching and a stage of iron and aluminum removal in sequence, and a stage of iron-aluminum slag and a nickel-cobalt solution are obtained after solid-liquid separation; the reduction leaching comprises the following steps: the nickel-cobalt hydroxide raw material is made into a slurry, the liquid-solid ratio in the slurry is 6-10:1, and the reaction temperature is 60-90°C; concentrated sulfuric acid is injected into the slurry to dissolve the slurry, and stirred for 0.2-0.5h, and the amount of concentrated sulfuric acid added is 600-900kg / t 干矿料 ; Then, dilute sulfuric acid with a concentration of 10-40wt% is added dropwise to the slurry, the pH is adjusted to 1.2-2.5, and stirring is continued at 300-800r / min for 1-2h; Then, a first reducing agent is added to the slurry, and after reacting for 0.5-1h, the reaction liquid is separated into a solid-liquid state to obtain a filter residue and a filtrate; The first stage of iron and aluminum removal is specifically as follows: a first neutralizing agent is added to the filtrate separated in the reduction leaching step to adjust the pH to 4.5-5.2; Then, an oxidant is added to the filtrate, and the reaction is carried out at a speed of 300-800r / min at 60-90°C for 3-5h; After solid-liquid separation of the oxidized reaction liquid, a first stage of iron and aluminum slag and a nickel-cobalt solution is obtained; The first-stage iron-aluminum slag is ripened and leached, and the leachate is solid-liquid separated to obtain silicon slag and desiliconized filtrate; the first-stage iron-aluminum slag is ripened and leached specifically as follows: the first-stage iron-aluminum slag is mixed with concentrated sulfuric acid at a rate of 500-900 kg / t, stirred for 1-3 hours, and then water is added to a liquid-solid ratio of 3-10:1, and a second reducing agent is added to reduce at 80-95° C. for 0.3-1 hour; Adding a neutralizing agent to the desiliconization filtrate to perform two-stage iron and aluminum removal, and obtaining two-stage iron and aluminum slag and impurity removal filtrate after solid-liquid separation; wherein the neutralizing agent is Na2CO3, adjusting the pH to 4.5-5.2, and the reaction time is 3-5h; The impurity-removing filtrate is subjected to nickel precipitation treatment, and after solid-liquid separation, filter residue NiCO3 and filtrate Na2SO4 are obtained; the impurity-removing filtrate is subjected to nickel precipitation treatment specifically as follows: adding a neutralizing agent Na2CO3 to the impurity-removing filtrate, adjusting the pH to 7-8, and reacting at 40-70°C for 2-4h; The filter residue NiCO3 is recycled to the first iron and aluminum removal step, and the filtrate Na2SO4 is evaporated and crystallized to obtain the by-product Glauber's salt.

2. The method for treating nickel-cobalt hydroxide according to claim 1, characterized in that: The first reducing agent is any one of H2O2 and SO2 or a mixture of the two, and the first reducing agent usage coefficient: the first reducing agent usage / Mn content of nickel cobalt hydroxide is 0.2-1 mol / mol.

3. The method for treating nickel-cobalt hydroxide according to claim 1, characterized in that: The first neutralizing agent is a nickel cobalt hydroxide raw material or NiCO3; the first neutralizing agent is prepared into a slurry for use, and the solid content in the slurry is 30-50%; The oxidant is air or H2O2; when the oxidant is air, the air flow rate is 50-200 mL / min, and when the oxidant is H2O2, the amount of H2O2 is 1.4 kg / t liquid.

4. The method for treating nickel-cobalt hydroxide according to claim 1, characterized in that: The second reducing agent is any one of H2O2 and SO2 or a mixture of the two, and the coefficient of the second reducing agent is: the amount of the second reducing agent / the amount of Mn contained in the nickel-cobalt hydroxide is 0.5-1.5 mol / mol.

5. The method for treating nickel-cobalt hydroxide according to claim 1, characterized in that: The method further comprises extracting the nickel-cobalt solution.

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