Method for recovering mn, mg, ni, and co from laterite-nickel ore tailings

Abstract

Disclosed in the present invention is a method for recovering Mn, Mg, Ni, and Co from laterite-nickel ore tailings. The method comprises the following steps: adding concentrated sulfuric acid to an underflow from thickened laterite-nickel ore tailings for first-stage leaching to obtain a magnesium sulfate solution and tailings with magnesium preliminarily removed; slurrying the tailings with magnesium preliminarily removed and then adding concentrated sulfuric acid and hydrogen peroxide for second-stage leaching to obtain a crude manganese solution; adjusting the pH of the solution to 5-7 to undergo a reaction to remove impurities such as Fe, Al, Sc, and Si from the crude manganese solution, and carrying out pressure filtration to obtain a manganese solution subjected to preliminary impurity removal; and then adding a sulfide for deep impurity removal to remove Ni and Co, and carrying out filtration to obtain a qualified manganese electrolyte solution and cobalt nickel sulfide residue. The present invention creatively proposes a method for recovering Mn, Mg, Ni, and Co from laterite-nickel ore tailings. The recovery process does not need heating and has a small consumption of auxiliary materials, and a low cost. The extracted manganese sulfate solution can completely meet the requirements for electrolytic manganese.

Description

A method for recovering Mn, Mg, Ni and Co from laterite nickel ore tailings Technical Field

[0001] The invention belongs to the field of metallurgy, and in particular relates to a method for recovering Mn, Mg, Ni and Co from laterite nickel ore tailings. Background Art

[0002] Currently, the tailings generated after alkaline precipitation of nickel ore to produce MHP are often landfilled due to their low content of valuable metals such as Mn, Mg, Ni, and Co, and the presence of various impurities, making them difficult to recycle as resources. This results in a significant waste of metal resources. The manganese content in laterite nickel ore is nearly equivalent to that of nickel. During the alkaline precipitation of nickel and cobalt, less than 20% of the manganese enters the MHP, while the remaining manganese is precipitated after precipitation and enters the discharged slag. However, the recovery and extraction of manganese resources from laterite nickel ore tailings has been a neglected issue. As is well known, the raw materials for electrolytic manganese are currently manganese ores such as manganese carbonate and rhodochrosite. Manganese carbonate and rhodochrosite are not only in short supply in my country, but also have high mining costs and complex composition. This not only results in low manganese ore utilization but also compromises the quality of the resulting manganese electrolyte. Furthermore, manganese ores such as manganese carbonate and rhodochrosite present the following challenges: 1. Their prices are influenced by supply and demand and market fluctuations. Insufficient raw material supply or rising prices will increase electrolytic manganese production costs. Second, supply may be affected by factors such as geological resource distribution and mining environmental regulations. Unstable raw material supply can lead to production disruptions or increased costs. Therefore, recovering Mn from laterite nickel ore tailings would not only solve the problem of tailings being landfilled, but also alleviate the aforementioned issues with manganese ore resources.

[0003] Summary of the Invention

[0004] In view of the shortcomings of the prior art, the object of the present invention is to provide a method for recovering Mn, Mg, Ni and Co from laterite nickel ore tailings.

[0005] The process of the present invention does not require heating, consumes less auxiliary materials, and has low cost. The two-stage leaching not only realizes the recovery of magnesium but also improves the purity of the manganese electrolyte. The extracted manganese sulfate solution can fully meet the requirements of electrolytic manganese.

[0006] The purpose of the present invention is achieved through the following technical solutions:

[0007] A method for recovering Mn, Mg, Ni and Co from laterite nickel ore tailings comprises the following steps:

[0008] (1) adding concentrated sulfuric acid in the underflow after the laterite nickel ore tailings are dense, carrying out one-stage leaching at normal temperatures, and filtering after leaching to obtain the tailings after magnesium sulfate solution and pre-magnesium removal;

[0009] (2) adding water to the tailings after pre-magnesium removal to slurry it, adding concentrated sulfuric acid after stirring, and then adding hydrogen peroxide to carry out two-stage leaching, and filtering after the two-stage leaching to obtain a crude manganese solution;

[0010] (3) adjusting the pH of the crude manganese solution to 5-7, carrying out a reaction, removing impurity elements such as Fe, Al, Sc, and Si in the crude manganese solution, and filtering to obtain a manganese solution after preliminary impurity removal;

[0011] (4) Add sulfide to the manganese solution after preliminary impurity removal to carry out deep impurity removal reaction to remove Ni and Co, and filter to obtain qualified manganese electrolyte and nickel-cobalt sulfide slag.

[0012] Preferably, the initial concentration of sulfuric acid in the underflow of the thickened laterite nickel ore tailings in step (1) is 0.01 to 0.5 mol / L.

[0013] Preferably, the leaching time in step (1) is 1 to 30 minutes.

[0014] Preferably, water is added to the tailings after pre-magnesium removal in step (2), and the liquid-to-solid ratio is 0.5-5m 3 / t.

[0015] Preferably, concentrated sulfuric acid is added after stirring for 1 min in step (2).

[0016] Preferably, the liquid-to-solid ratio of the concentrated sulfuric acid in step (2) to the tailings after pre-magnesium removal is 0.1 to 1:1.

[0017] Preferably, the liquid-to-solid ratio of the hydrogen peroxide in step (2) to the tailings after pre-magnesium removal is 0.05-0.15:1.

[0018] Preferably, the concentration of the hydrogen peroxide in step (2) is 5-30%.

[0019] Preferably, the second leaching time in step (2) is 5 minutes to 60 minutes.

[0020] Preferably, the concentration of the concentrated sulfuric acid in step (1) and step (2) is both 98% concentrated sulfuric acid.

[0021] Preferably, the pH of the crude manganese solution is adjusted in step (3) by adding at least one of aqueous ammonia and sodium hydroxide.

[0022] Preferably, the reaction time in step (3) is 10 to 60 minutes.

[0023] Preferably, the solid-to-liquid ratio of the sulfide in step (4) to the manganese solution after preliminary impurity removal is 0.2-0.8 kg / m 3 .

[0024] Preferably, the sulfide in step (4) is at least one of hydrogen sulfide, sodium sulfide, manganese sulfide and sodium thiamethoxam.

[0025] Preferably, the reaction time in step (4) is 0.25 to 3 hours.

[0026] Preferably, the nickel-cobalt sulfide slag in step (4) subsequently enters the high-grade nickel matte line for nickel and cobalt recovery.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] The present invention proposes a new process for comprehensively recovering various valuable metals, including Mn, Mg, Ni and Co, from laterite nickel ore tailings. The entire process does not require heating, consumes less auxiliary materials, and is low in cost. The two-stage leaching not only achieves magnesium recovery but also improves the purity of the manganese electrolyte. The extracted manganese sulfate solution can fully meet the requirements of electrolytic manganese. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] FIG1 is a flow chart of the method for recovering Mn, Mg, Ni and Co from laterite nickel ore tailings according to the present invention. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0031] The concentration of the hydrogen peroxide in the embodiment is 30%, and the concentration of the concentrated sulfuric acid is 98%.

[0032] Example 1

[0033] A method for recovering Mn, Mg, Ni and Co from laterite nickel ore tailings, comprising the following steps:

[0034] The solid content of the tailings underflow after thickening by the thickener of the laterite nickel ore tailings is 31.9%, and the slag phase composition is shown in Table 1.

[0035] Table 1 List of tailings components

[0036] (1) Concentrated sulfuric acid was added to the underflow of the laterite nickel ore tailings after the tailings were thickened to make the initial sulfuric acid concentration in the underflow reach 0.09 mol / L. After stirring and reacting for 5 minutes, the solution was washed with a filter press to obtain a magnesium sulfate solution and a tailing after pre-magnesium removal. The components of the leachate and the tailing after pre-magnesium removal are shown in Table 2 and Table 3, respectively.

[0037] Table 2 List of ingredients of magnesium sulfate solution

[0038] Table 3 List of tailings components after pre-magnesium removal

[0039] (2) Add water to the tailings after pre-magnesium removal and stir to slurry them at room temperature, with a liquid-to-solid ratio of 1.33m 3 / t, stirred and reacted for 1 minute, then concentrated sulfuric acid was added, wherein the liquid-to-solid ratio was 0.27, and finally hydrogen peroxide was added, wherein the liquid-to-solid ratio was 0.08, stirred and reacted for 15 minutes, and filtered to obtain a crude manganese solution after leaching of laterite nickel ore tailings. The composition is shown in Table 4:

[0040] Table 4 Composition of crude manganese sulfate solution

[0041] (3) The pH of the crude manganese sulfate solution was adjusted to 5.5, the reaction time was 20 min, and the manganese sulfate solution was obtained by filter pressing after removing iron, aluminum, and other trace impurities such as Sc and Si. The composition is shown in Table 5.

[0042] Table 5 Composition of manganese sulfate solution after iron and aluminum removal

[0043] (4) Add sodium fumarate to the manganese sulfate solution obtained in step (3) with a solid-liquid ratio of 0.5 kg / m 3 The reaction time was 2 h, and the manganese sulfate solution and nickel-cobalt sulfide slag after nickel and cobalt precipitation were obtained by filter pressing. The compositions of the two solutions are shown in Table 6 and Table 7, respectively.

[0044] Table 6 List of ingredients of qualified manganese sulfate solution

[0045] Table 7 Composition of nickel-cobalt sulfide slag

[0046] As shown in Tables 6 and 7, the manganese sulfate solution, after dilution with water, fully meets the requirements of electrolysis. Furthermore, the nickel-cobalt sulfide contains very low levels of other impurities, allowing it to be directly fed into the production line's high-grade nickel matte autoclave for nickel and cobalt recovery.

[0047] Example 2

[0048] In order to obtain a manganese sulfate electrolyte with a target concentration without dilution, the following adjustments were made based on Example 1.

[0049] (1) After pre-leaching and magnesium removal, the volume of water in the slurry of the laterite nickel ore tailings after pre-magnesium removal in step (2) of Example 1 was increased to a liquid-to-solid ratio of 1.81m 3 / t, other process parameters remain unchanged, the composition of the crude manganese solution obtained by filter pressing is shown in Table 8:

[0050] Table 8 Composition of crude manganese sulfate solution

[0051] (2) The pH of the crude manganese sulfate solution was adjusted to 5.5, and the reaction time was reduced to 15 min. The manganese sulfate solution after removing iron, aluminum, and other trace impurities such as Sc and Si was obtained by filter pressing. The composition is shown in Table 9 below.

[0052] Table 9 Composition of manganese sulfate solution after iron and aluminum removal

[0053] (3) Sodium fumarate was added to the manganese sulfate solution obtained in step (3) to reduce the solid-liquid ratio to 0.37 kg / m 3 The reaction time is 1.5 h. The manganese sulfate solution obtained by filter pressing can be directly supplied to the electrolytic cell without dilution, as shown in Table 10.

[0054] Table 10 Composition of undiluted manganese sulfate solution

[0055] Example 3

[0056] The solid content of the tailings underflow after thickening by the thickener of the laterite nickel ore tailings is 38%, and the slag phase composition is shown in Table 11.

[0057] Table 11 List of tailings components

[0058] (1) Concentrated sulfuric acid was added to the underflow of the laterite nickel ore tailings after the tailings were thickened to make the initial sulfuric acid concentration in the underflow reach 0.107 mol / L. After stirring and reacting for 5 minutes, the solution was washed with a filter press to obtain a magnesium sulfate solution and a tailing after pre-magnesium removal. The components of the leachate and the tailing after pre-magnesium removal are shown in Table 12 and Table 13, respectively.

[0059] Table 12: Composition of magnesium sulfate solution

[0060] Table 13 List of tailings components after pre-magnesium removal

[0061] (2) Add water to the tailings after pre-magnesium removal and stir to slurry them at room temperature, with a liquid-to-solid ratio of 1.33m 3 / t, stirred and reacted for 1 minute, then concentrated sulfuric acid was added, wherein the liquid-to-solid ratio was 0.32, and finally hydrogen peroxide was added, wherein the liquid-to-solid ratio was 0.096, stirred and reacted for 15 minutes, and filtered to obtain a crude manganese solution after leaching of laterite nickel ore tailings. The composition is shown in Table 14:

[0062] Table 14 Composition of crude manganese sulfate solution

[0063] (3) The pH of the crude manganese sulfate solution was adjusted to 6, the reaction time was 20 min, and the manganese sulfate solution was obtained by filter pressing after removing iron, aluminum, and other trace impurities such as Sc and Si. The composition is shown in Table 15.

[0064] Table 15 Composition of manganese sulfate solution after iron and aluminum removal

[0065] (4) Add sodium fumarate to the manganese sulfate solution obtained in step (3) with a solid-liquid ratio of 0.6 kg / m 3 The reaction time was 2 h, and the manganese sulfate solution and nickel-cobalt sulfide slag after the nickel and cobalt were precipitated were obtained by filter pressing. The compositions of the two solutions are shown in Table 16 and Table 17, respectively.

[0066] Table 16 List of ingredients of qualified manganese sulfate solution

[0067] Table 17 Composition of nickel-cobalt sulfide slag

[0068] The specific embodiments of the present invention described above do not limit the scope of protection of the present invention. Any other corresponding changes and modifications made based on the technical concept of the present invention should be included in the scope of protection of the claims of the present invention.

Claims

1. A method for recovering Mn, Mg, Ni and Co from laterite nickel ore tailings, It is characterized in that The steps include: (1) adding concentrated sulfuric acid to the underflow after the laterite nickel ore tailings are dense, performing a leaching step at room temperature, and performing filter pressing after the leaching is completed to obtain a magnesium sulfate solution and a tailings after pre-magnesium removal; (2) adding water to the tailings after pre-magnesium removal to slurry it, adding concentrated sulfuric acid after stirring, and then adding hydrogen peroxide to carry out two-stage leaching, and filtering after the two-stage leaching to obtain a crude manganese solution; (3) adjusting the pH of the crude manganese solution to 5-7, performing a reaction, removing impurity elements such as Fe, Al, Sc and Si in the crude manganese solution, and filtering to obtain a manganese solution after preliminary impurity removal; (4) adding sulfide to the manganese solution after preliminary impurity removal to carry out deep impurity removal reaction, remove Ni and Co, and filter to obtain qualified manganese electrolyte and nickel-cobalt sulfide slag.

2. The method for recovering Mn, Mg, Ni and Co from laterite nickel ore tailings according to claim 1, It is characterized in that In the underflow after the thickening of the laterite nickel ore tailings in step (1), the initial concentration of sulfuric acid is 0.01 to 0.5 mol / L; In step (2), water is added to the tailings after pre-magnesium removal, and the liquid-to-solid ratio is 0.5-5m 3 / t.

3. The method for recovering Mn, Mg, Ni and Co from laterite nickel ore tailings according to claim 1, It is characterized in that The liquid-to-solid ratio of the hydrogen peroxide solution to the pre-magnesium-removed tailings in step (2) is 0.05-0.15:1; The liquid-to-solid ratio of the concentrated sulfuric acid to the tailings after pre-magnesium removal in step (2) is 0.1 to 1:1; The solid-to-liquid ratio of the sulfide in step (4) to the manganese solution after preliminary impurity removal is 0.2 to 0.8 kg / m 3 .

4. A method for recovering Mn, Mg, Ni and Co from laterite nickel ore tailings according to any one of claims 1 to 3, It is characterized in that The concentration of the hydrogen peroxide in step (2) is 5 to 30%; The concentration of the concentrated sulfuric acid in step (1) and step (2) is both 98% concentrated sulfuric acid.

5. The method for recovering Mn, Mg, Ni and Co from laterite nickel ore tailings according to claim 1, It is characterized in that The leaching time in step (1) is 1 to 30 minutes; The time of the second stage leaching in step (2) is 5 min to 60 min.

6. The method for recovering Mn, Mg, Ni and Co from laterite nickel ore tailings according to claim 5, It is characterized in that The reaction time of step (3) is 10 to 60 minutes.

7. The method for recovering Mn, Mg, Ni and Co from laterite nickel ore tailings according to any one of claims 1 to 3, It is characterized in that The method of adjusting the pH of the crude manganese solution in step (3) is to adjust the pH by adding at least one of ammonia water and sodium hydroxide.

8. The method for recovering Mn, Mg, Ni and Co from laterite nickel ore tailings according to any one of claims 1 to 3, It is characterized in that The sulfide in step (4) is at least one of hydrogen sulfide, sodium sulfide, manganese sulfide and sodium thiram.

9. The method for recovering Mn, Mg, Ni and Co from laterite nickel ore tailings according to claim 1, It is characterized in that The reaction time of step (4) is 0.25 to 3 hours.

10. The method for recovering Mn, Mg, Ni and Co from laterite nickel ore tailings according to claim 1, It is characterized in that The nickel-cobalt sulfide slag in step (4) subsequently enters the high-grade nickel matte line for nickel and cobalt recovery.

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