Method for recovering manganese from laterite-nickel ore

Abstract

The invention relates to a method for recovering manganese from laterite-nickel ore, which comprises the following steps: introducing CO2 gas into nickel and cobalt precipitation supernatant of the laterite-nickel ore, adjusting the pH value of the solution to 6.0-7.0, carrying out precipitation reaction, and carrying out solid-liquid separation to obtain a precipitate containing manganese carbonate; mixing the precipitate containing manganese carbonate with water to obtain a turbid liquid, adjusting the pH value of the turbid liquid to 0.5-6.0, carrying out a leaching reaction, and carrying out solid-liquid separation to obtain a manganese-containing leachate; and different sulfides are jointly added into the manganese-containing lixivium for impurity removal treatment, and manganese recovery liquid is obtained through solid-liquid separation. The manganese recovery liquid can be directly applied to manganese electrodeposition, and compared with the prior art, the method has the advantages that the preparation process flow of the manganese electrodeposition liquid is greatly simplified, the production cost is reduced, and the quality of the obtained manganese electrodeposition liquid is high.

Description

Technical Field

[0001] The invention relates to the technical field of heavy metal recovery, and in particular to a method for recovering manganese from laterite nickel ore. Background Art

[0002] After the laterite nickel ore is prepared into nickel cobalt hydroxide (MHP) by the hydrometallurgical process, a large amount of manganese liquid will be produced. At present, these manganese liquids are directly discharged, or these manganese liquids are precipitated into manganese slag by natural precipitation means, and finally landfilled. This not only poses a potential threat to the environment, but also leads to the waste of manganese resources. Assuming that the annual output of nickel recovered from the laterite nickel ore by an enterprise is 100,000 gold tons, then 40,000-65,000 gold tons of manganese resources will be wasted in a year. Manganese is an important strategic resource, and its grade is also rapidly declining while the manganese ore in the world is being mined in large quantities. Therefore, it has become a problem that needs to be solved urgently to effectively develop methods and technologies for extracting and recovering secondary manganese resources from a large amount of manganese liquid produced after the laterite nickel ore is precipitated into MHP. Summary of the invention

[0003] In view of the problems existing in the existing industry, the purpose of the present invention is to provide a method for recovering manganese from laterite nickel ore, utilizing the difference in the solubility product of metal carbonates to preferentially precipitate manganese elements, and then efficiently leaching manganese through acidification treatment. Finally, different sulfides are added to the manganese-containing leaching solution for impurity removal. The manganese recovery solution obtained by solid-liquid separation can be directly used for manganese electrowinning to prepare manganese plates. The present invention proposes a method and application for recovering manganese from the manganese solution after MHP precipitation from laterite nickel ore. Compared with the prior art, the manganese recovery method of the present invention not only greatly simplifies the preparation process of manganese electrowinning solution and reduces production costs, but also the obtained manganese electrowinning solution has high quality.

[0004] To achieve this object, the present invention adopts the following technical solutions:

[0005] The present invention provides a method for recovering manganese from laterite nickel ore, comprising the following steps:

[0006] (1) introducing CO2 gas into the supernatant of nickel-cobalt precipitation of laterite nickel ore, adjusting the pH of the solution to 6.0-7.0 for precipitation reaction, and after the precipitation reaction is completed, obtaining a precipitate containing manganese carbonate by solid-liquid separation;

[0007] (2) mixing the precipitate containing manganese carbonate with water to obtain a suspension, adjusting the pH of the suspension to 0.5 to 6.0 for leaching reaction, and after the leaching reaction is completed, obtaining a manganese-containing leaching solution by solid-liquid separation;

[0008] (3) adding different sulfides to the manganese-containing leaching solution for impurity removal, controlling the pH value during the impurity removal process not to exceed 7.0, and obtaining a manganese recovery solution through solid-liquid separation after the impurity removal process is completed.

[0009] The present invention provides a method for recovering manganese from laterite nickel ore, which utilizes the difference in solubility product of metal carbonates to preferentially precipitate manganese elements, and then efficiently recovers manganese through acidification treatment. Finally, different sulfides are added to remove impurities from the manganese leaching solution, and the purified manganese recovery solution can be directly used for manganese electrowinning. The present invention proposes a method and application for recovering manganese from manganese solution after MHP precipitation from laterite nickel ore. Compared with the prior art, the manganese recovery method of the present invention not only greatly simplifies the preparation process of manganese electrowinning solution and reduces production costs, but also the obtained manganese electrowinning solution has high quality.

[0010] It should be noted that the combined addition of different sulfides in step (3) of the present invention refers to the selection of the type of sulfide according to the specific use requirements of the final manganese recovery liquid, and the combined addition can be selected to be added simultaneously or sequentially.

[0011] In step (1) of the present invention, the pH of the solution is adjusted to 6.0-7.0, for example, 6.0, 6.1, 6.2, 6.3, 6.4, 6.5, 6.6, 6.7, 6.8, 6.9 or 7.0.

[0012] In step (2) of the present invention, the pH of the suspension is adjusted to 0.5-6.0, for example, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0, 5.5 or 6.0.

[0013] In step (3) of the present invention, the pH value during the impurity removal treatment is controlled not to exceed 7.0, for example, 6.8, 6.7, 6.5, 6.3, 6.0, 5.7, 5.5 or 5.0.

[0014] As a preferred technical solution of the present invention, in the supernatant of nickel and cobalt precipitated into laterite nickel ore in step (1), Mn 1-2 g / L, Ni 0-0.003 g / L, Co 0-0.004 g / L, Fe 0-0.001 g / L, Al 0-0.0015 g / L, Cu 0-0.002 g / L, Zn 0-0.003 g / L, Ca 0.5-0.7 g / L, and Mg 5-7 g / L.

[0015] As a preferred technical solution of the present invention, the flow rate of CO2 gas introduced in step (1) is 10 to 300 L / h, for example, 10 L / h, 50 L / h, 100 L / h, 120 L / h, 150 L / h, 200 L / h, 250 L / h or 300 L / h, etc.

[0016] As a preferred technical solution of the present invention, the specific step of adjusting the pH of the solution to 6.0-7.0 in step (1) includes: adjusting the pH of the solution by adding an alkaline substance, wherein the alkaline substance includes at least one of calcium carbonate, calcium oxide, calcium hydroxide or sodium hydroxide.

[0017] As a preferred technical solution of the present invention, in step (1), the precipitation reaction time is 0.5 to 8 h, for example, 0.5 h, 1 h, 2 h, 3 h, 4 h, 5 h, 6 h, 7 h or 8 h, and the precipitation reaction temperature is 25 to 90 ° C, for example, 25 ° C, 35 ° C, 45 ° C, 55 ° C, 65 ° C, 75 ° C, 85 ° C or 90 ° C, etc.

[0018] As a preferred technical solution of the present invention, the precipitate containing manganese carbonate and water in step (2) are mixed at a solid-to-liquid mass ratio of 1:1 to 10, for example, 1:1, 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9 or 1:10.

[0019] As a preferred technical solution of the present invention, the specific step of adjusting the pH of the suspension to 0.5-6.0 in step (2) includes: adjusting the pH of the suspension by adding an acidic substance, wherein the acidic substance includes at least one of hydrochloric acid, sulfuric acid or nitric acid.

[0020] As a preferred technical solution of the present invention, in step (2), the temperature of the leaching reaction is 25-90°C, for example, 25°C, 35°C, 45°C, 55°C, 65°C, 75°C, 85°C or 90°C, and the time of the leaching reaction is 0.1-6h, for example, 0.1h, 0.5h, 1h, 2h, 3h, 4h, 5h or 6h, etc.

[0021] As a preferred technical solution of the present invention, in step (3), each of the sulfides is mixed with the manganese-containing leaching solution in a solid-liquid mass ratio of 1 to 5000:100000, for example, 1:100000, 100:100000, 500:100000, 1000:100000, 3000:100000 or 5000:100000, etc., and the sulfide includes at least one of sodium thiamethoxam, manganese sulfide, ammonium sulfide or barium sulfide.

[0022] Preferably, if the manganese recovery liquid is used for manganese electrowinning to obtain a manganese plate, in step (3), at least one of manganese sulfide, ammonium sulfide or barium sulfide is first added at 0.01 to 1 g / L, for example, 0.01 g / L, 0.05 g / L, 0.1 g / L, 0.3 g / L, 0.5 g / L, 0.7 g / L or 1 g / L, and then sodium thiocarbamide is added at 0.01 to 1 g / L, for example, 0.01 g / L, 0.05 g / L, 0.1 g / L, 0.3 g / L, 0.5 g / L, 0.7 g / L or 1 g / L, to remove various impurity ions of Fe, Al, Ni, Co, Zn and Cu in the manganese liquid, and the impurity removal effect is better.

[0023] As a preferred technical solution of the present invention, the time for the impurity removal treatment in step (3) is 0.1 to 10 hours, for example, 0.1 h, 0.5 h, 1 h, 2 h, 3 h, 4 h, 5 h, 6 h, 7 h, 8 h, 9 h or 10 h.

[0024] Compared with the prior art solutions, the present invention has at least the following beneficial effects:

[0025] (1) The present invention proposes a method for recovering manganese from a manganese solution after precipitation of MHP from laterite nickel ore and its application. The difference in solubility products of metal carbonates is utilized to preferentially precipitate manganese, and then manganese is efficiently leached by acidification. Finally, different sulfides are added to the manganese-containing leaching solution for impurity removal. The manganese recovery solution obtained by solid-liquid separation can be directly used for manganese electrowinning to prepare manganese plates.

[0026] (2) The manganese recovery solution of the present invention can be directly applied to manganese electrolysis. Compared with the existing preparation process of manganese electrolysis solution, the method of the present invention can save two steps of neutralization and impurity removal, greatly simplifying the preparation process of manganese electrolysis solution and reducing production costs.

[0027] (3) Compared with the existing manganese electrolytic solution preparation process, the manganese electrolytic solution prepared by the method of the present invention has higher quality, especially lower magnesium and sodium concentrations and can remove heavy metal impurities more cleanly. Therefore, the manganese electrolytic solution prepared by the method can effectively improve the electrolytic efficiency and manganese plate purity in the manganese electrolytic process, and can greatly reduce the problem of diaphragm bag blockage caused by magnesium crystallization in the manganese electrolytic process. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 The present invention is a process flow chart of the method for recovering manganese from laterite nickel ore. DETAILED DESCRIPTION

[0029] The technical solution of the present invention is further described below with reference to the accompanying drawings and through specific implementation methods.

[0030] The present invention provides a method for recovering manganese from laterite nickel ore, such as Figure 1As shown, the following steps are included:

[0031] (1) introducing CO2 gas into the supernatant of nickel-cobalt precipitation of laterite nickel ore, and adjusting the pH of the solution to 6.0-7.0 to carry out precipitation reaction, and after the precipitation reaction is completed, obtaining a precipitate containing manganese carbonate by solid-liquid separation;

[0032] (2) mixing the precipitate containing manganese carbonate with water to obtain a suspension, adjusting the pH of the suspension to 0.5 to 6.0 for leaching reaction, and after the leaching reaction is completed, obtaining a manganese-containing leaching solution by solid-liquid separation;

[0033] (3) adding different sulfides to the manganese-containing leaching solution for impurity removal, controlling the pH value during the impurity removal process not to exceed 7.0, and obtaining a manganese recovery solution through solid-liquid separation after the impurity removal process is completed.

[0034] To better illustrate the present invention and facilitate understanding of the technical solution of the present invention, typical but non-limiting embodiments of the present invention are as follows:

[0035] Example 1

[0036] This embodiment provides a method for recovering manganese from laterite nickel ore, comprising the following steps:

[0037] (1) Manganese precipitation

[0038] 1L of nickel-cobalt supernatant (Mn 1.43g / L, Ni 0.002g / L, Co 0.004g / L, Fe0.001g / L, Al 0.001g / L, Cu 0.0015g / L, Zn 0.002g / L, Ca 0.55g / L, Mg 6g / L) was introduced with CO2 gas at a flow rate of 50L / h, and then a calcium hydroxide solution with a concentration of 20wt% was added to adjust the solution pH to 6.9 for precipitation reaction. The precipitation reaction temperature was 50°C and the reaction was carried out for 1.5h. A precipitate containing manganese carbonate was obtained by filtration. The composition of the precipitate was as follows: Mn: 24.58wt%, Ni: 0.004wt%, Co: 0.007wt%, Fe: 0.009wt%, Al: 0.009wt%, Cu: 0.015wt%, Zn: 0.012wt%, Ca: 1.62wt%, and Mg: 0.45wt%.

[0039] (2) Manganese leaching

[0040] Take 240g of the above-mentioned precipitate containing manganese carbonate, add 1L of water to mix and obtain a suspension, then add sulfuric acid to the suspension and adjust its pH to 4.5 for leaching reaction. The leaching reaction temperature is 50°C, the reaction time is 30min, and the manganese-containing leachate and filter residue are obtained by filtration. The components of the manganese-containing leachate are as follows: Mn: 42.56g / L, Ni: 0.006g / L, Co: 0.008g / L, Fe: 0.003g / L, Al: 0.009g / L, Cu: 0.012g / L, Zn: 0.014g / L, Ca: 0.54g / L, Mg: 0.83g / L.

[0041] (3) Manganese liquid impurity removal:

[0042] Take 1L of the above manganese-containing leachate, add 0.13g / L barium sulfide, and then carry out impurity removal treatment at 50°C for 1.5h. After testing, the endpoint pH of the reaction system is stable at 6.5. After the reaction is completed, continue to add 0.05g / L sodium fumei to react for 2h. After the reaction is completed, filter and let the filtrate stand for 12h to obtain manganese recovery liquid and filter residue. After testing, the pH of the manganese recovery liquid is 6.8, and its components are: Mn: 41.65g / L, Ni / Co / Fe / Al / Cu / Zn: 0g / L, Ca: 0.54g / L, Mg: 0.83g / L, Ba: 0.001g / L, Na: 0.013g / L.

[0043] Example 2

[0044] This embodiment provides a method for recovering manganese from laterite nickel ore. Compared with Example 1, the only difference is that the flow rate of CO2 gas in step (1) is increased to 120L / h; the relevant test results are as follows:

[0045] (1) Manganese precipitation:

[0046] The composition of the precipitate is as follows: Mn: 23.01wt%, Ni: 0.005wt%, Co: 0.008wt%, Fe: 0.011wt%, Al: 0.012wt%, Cu: 0.019wt%, Zn: 0.016wt%, Ca: 1.79wt%, Mg: 0.56wt%.

[0047] (2) Manganese leaching:

[0048] The composition of the manganese-containing leaching solution is as follows: Mn: 39.85 g / L, Ni: 0.006 g / L, Co: 0.008 g / L, Fe: 0.003 g / L, Al: 0.009 g / L, Cu: 0.012 g / L, Zn: 0.014 g / L, Ca: 0.56 g / L, Mg: 0.97 g / L. Since the pH of the system during manganese leaching is the same as that in Case 1, according to the ion balance relationship, the impurities in the obtained manganese filtrate are

[0049] (3) Manganese liquid impurity removal:

[0050] Take 1L of the above manganese-containing leachate, add 0.13g / L barium sulfide, and then carry out impurity removal treatment at 50°C for 1.5h. After testing, the endpoint pH of the reaction system is stable at 6.5. After the reaction is completed, continue to add 0.05g / L sodium fumei to react for 2h. After the reaction is completed, filter and let the filtrate stand for 12h to obtain manganese recovery liquid and filter residue. After testing, the manganese recovery liquid has a pH of 6.8, and its components are: Mn: 38.90g / L, Ni / Co / Fe / Al / Cu / Zn: 0g / L, Ca: 0.56g / L, Mg: 0.97g / L, Ba 0.001g / L, Na0.013g / L.

[0051] Example 3

[0052] This embodiment provides a method for recovering manganese from laterite nickel ore. Compared with Embodiment 1, the only difference is that in step (2), the pH of the solution is adjusted to 2.5 during manganese leaching; the process adjustment and related test results are as follows:

[0053] (2) Manganese leaching:

[0054] The composition of the manganese-containing leaching solution is as follows: Mn: 44.10 g / L, Ni: 0.008 g / L, Co: 0.009 g / L, Fe: 0.010 g / L, Al: 0.014 g / L, Cu: 0.014 g / L, Zn: 0.018 g / L, Ca: 0.55 g / L, Mg: 0.87 g / L.

[0055] (3) Manganese liquid impurity removal:

[0056] Take 1L of the above manganese-containing leaching solution, add 0.2g / L barium sulfide, and then carry out impurity removal treatment at 50°C for 1.5h. After testing, the endpoint pH of the reaction system is stable at 5.9. After the reaction is completed, continue to add 0.05g / L sodium fumei to react for 2h. After the reaction is completed, filter and let the filtrate stand for 12h to obtain manganese recovery liquid and filter residue. After testing, the pH of the manganese recovery liquid is 6.8, and its components are: Mn: 43.02g / L, Ni / Co / Fe / Al / Cu / Zn: 0g / L, Ca: 0.57g / L, Mg: 0.87g / L, Ba: 0.001g / L, Na 0.013g / L.

[0057] It can be seen that if the pH is lower during manganese leaching, the concentration of impurity elements in the manganese filtrate will be higher, which will increase the amount of sulfide used in the impurity removal stage, increase the impurity removal cost and affect the quality of the manganese recovery liquid.

[0058] Example 4

[0059] The present embodiment provides a method for recovering manganese from laterite nickel ore. Compared with Example 1, the only difference is that: in step (3), the amount of barium sulfide is reduced to 0.1 g / L when removing impurities from the manganese solution, and the amount of sodium fumei needs to be increased to 0.2 g / L; after testing, the pH value of the obtained manganese recovery solution is 6.1, and the manganese recovery solution contains Mn: 41.75 g / L, Ni / Co / Fe / Al / Cu / Zn: 0 g / L, Ca: 0.54 g / L, Mg: 0.83 g / L, Ba: 0.001 g / L, and Na 0.038 g / L.

[0060] It can be seen that as long as the dosage of barium sulfide and sodium fumer is well matched in the impurity removal stage, a manganese recovery liquid with Fe, Al, Ni, Co, Cu and Zn removed can be obtained. If the manganese recovery liquid is to be used for manganese electrowinning, in the electrowinning process section, add more ammonia water to adjust the pH of the manganese liquid to the reaction pH 6.8-7.2 required for manganese electrowinning. In addition, for manganese plates with relatively high quality requirements, the influence of sodium ions circulating on the purity of the electrowinning manganese plates in the entire process system should also be considered. Of course, in the case of facilitating production operations while taking into account product quality, it is necessary to balance the cost of each process section in order to reduce the cost of the final product.

[0061] Comparative Example 1

[0062] This comparative example provides a method for recovering manganese from laterite nickel ore. Compared with Example 1, the only difference is that in step (3) of removing impurities from the manganese solution, only barium sulfide is added, and the composition of the manganese recovery solution is, Mn: 41.98 g / L, Fe / Al / Cu / Zn: 0 g / L, Ni: 0.0013 g / L, Co: 0.0008 g / L, Ca: 0.54 g / L, Mg: 0.83 g / L, Ba: 0.001 g / L.

[0063] By comparing the solubility products of different sulfides, it can be seen that barium sulfide is weaker in removing Ni and Co than Zn and Cu. If barium sulfide is to be used to remove Ni and Co as much as possible, the amount of barium sulfide used for impurity removal will be multiplied several times, and even so, Ni and Co cannot be completely removed. Of course, this is also related to the fact that the current industrial-grade barium sulfide contains trace or small amounts of Ni and Co impurities. However, the industry has strict monitoring standards for the content of nickel and cobalt in electrolytic manganese plates. At present, the price of industrial-grade barium sulfide is high (60wt% purity), basically close to 10,000 yuan / ton. In actual production, it is necessary to optimize the production process and its parameters to avoid using too much barium sulfide to increase production costs.

[0064] Comparative Example 2

[0065] This comparative example provides a method for recovering manganese from laterite nickel ore. Compared with Example 1, the only difference is that in step (3) of removing impurities from the manganese solution, only sodium fumei is added, and the amount of sodium fumei added is increased to 0.6 g / L. After testing, the pH value of the manganese recovery solution is 5.1, and its components are Mn: 41.27 g / L, Ni / Co / Cu: 0 g / L, Fe: 0.0015 g / L, Al: 0.005 g / L, Zn: 0.002 g / L, Ca: 0.54 g / L, Mg: 0.83 g / L, 0.001 g / L Ba, and 0.165 g / L Na.

[0066] According to the production process of the manganese electrowinning project, even though sodium fumei has a strong chelating effect on metal ions, even if an excessive amount of sodium fumei is added, the removal effect of Zn is poor, which may be related to the smaller radius of Zn ions relative to other metal ions and the saturation of d-band electrons. However, the industry has strict monitoring standards for the zinc content in electrowinning manganese plates. In addition, it can be found that when barium sulfide is not added, Fe and Al in the manganese recovery liquid cannot be completely removed. This is because the pH is low during the impurity removal process and Fe and Al are not completely hydrolyzed.

[0067] Therefore, in the method described in the present invention, barium sulfide has two effects. On the one hand, it can increase the pH of the manganese filtrate when regulating impurities, and create a more suitable pH environment for continuing to remove heavy metals while removing iron and aluminum. On the other hand, better heavy metal removal effects can be achieved in the impurity removal stage, especially for Zn, and the amount of sodium thiocarbamide can be reduced at the same time to avoid the influence of too many sodium ions on the electrolytic deposition process and the purity of manganese plates after circulation in the entire process system. It should be noted that the barium sulfide currently on the market is very alkaline due to the preparation process, and it is generally believed that this is unfavorable and interferes with the optimization of the industrialization process. However, the relationship between different process sections of the process can be combined to make each component in the barium sulfide reagent play its role as much as possible.

[0068] It can be seen that the combined addition of different sulfides to remove impurities from the manganese filtrate proposed in the present invention not only has good impurity removal effect and low cost, but also can save two steps of neutralization and impurity removal compared to the traditional preparation process of manganese electrolytic solution.

[0069] In the hydrometallurgical process of laterite nickel ore, the temperature of the supernatant after nickel and cobalt precipitation is generally around 50-60°C. In order to avoid the cost caused by the supply of additional energy during manganese recovery, the chemical reactions in the cases of the present invention are all carried out at 50°C.

[0070] The method and ideas of manganese recovery of the present invention are now summarized and concluded, so as to expand the method to various fields of manganese and other metal recovery and application.

[0071] Due to the high total output of manganese in the supernatant (manganese liquid) after the laterite nickel ore is precipitated with MHP, the low concentration leads to difficulty in recovery. If extraction or various ion exchange methods are used to purify and enrich manganese, the manganese liquid needs to be pretreated and the manganese liquid water volume is large, so the equipment investment and process operation costs are both high. Therefore, priority is given to enrichment by chemical precipitation. Since carbon dioxide is abundant and the circulating leaching section of the MHP process of laterite nickel ore production will produce a large amount of carbon dioxide, but no enterprise currently recycles and uses it, based on considerations of the ecological environment and production costs, carbon dioxide is considered to be used for precipitation. In the precipitation process, the price of lime milk is relatively cheap relative to liquid alkali, sodium carbonate, etc., which can reduce the production cost during manganese enrichment. For the manganese filtrate after acid leaching, considering the requirements of the manganese electrolytic application field for electrolytic solution and the relevant industrialization process flow, therefore, the manganese filtrate is designed for impurity removal in a targeted and directional manner. At present, the price of manganese ore is high, but the manganese electrolytic process flow is cumbersome, which makes it difficult to compress the cost of manganese plate. At the same time, in the production process of manganese electrowinning, after magnesium and sodium circulate repeatedly in the entire process system, it is often encountered with magnesium crystallization, which causes pipeline crystallization and diaphragm bag blockage. The purity and quality of manganese plates are not high enough due to the influence of sodium and other heavy metal elements that are sometimes not completely removed, diaphragm bag blockage, and high viscosity of the electrolytic solution. Therefore, improving the quality of manganese electrolytic solution under the premise of reducing the manganese impurity removal process is of great significance for reducing the manganese production process, production costs, and the discharge of wastewater and waste residues in the entire process, as well as improving the quality and application of manganese plates. The following is a necessary introduction to the process described in the method of the present invention and its control direction:

[0072] For the method of the present invention, the manganese precipitation process section has a decisive influence on the recovery cost and recovery rate of manganese. In the manganese precipitation process, by controlling the inlet flow rate of CO2 and the reaction time conditions, it is possible to ensure that the precipitation rate of manganese reaches nearly 100%. However, this process section must pay attention to two aspects of the problem. On the one hand, in order to reduce the content of impurities such as Ni and Co in the obtained manganese carbonate, it is necessary to pay attention to the rate and reaction time of controlling the reaction. Among them, the reaction rate is determined by the type and concentration of the flow rate, pH, reaction temperature and pH regulator of the inlet CO2. It is very important to adjust these process variables so that they can cooperate well with each other. For example, if the reaction temperature of the system is high during manganese precipitation, the flow rate of pH or CO2 should be appropriately reduced. Under the premise of ensuring production efficiency, when other parameters are unchanged, the content of impurities such as Ni and Co in manganese carbonate will be increased if the inlet flow rate of pH is too high, the inlet flow rate of CO2 is too large, the temperature is too high and the reaction time is too long. At the same time, the alkalinity of the pH regulator should be noted, and the concentration of the pH regulator added to the reaction system should be optimized to avoid local over-alkalinity. On the other hand, it is important to control and inhibit the oxidation of manganese during the reaction process. The oxidation of manganese is affected by variables such as reaction temperature, reaction time, and CO2 flow rate. If the reaction time is too long, as the reaction system solution rolls, manganese will be oxidized to a high-valent state by air, which makes it difficult to leach manganese in the subsequent leaching stage, thereby reducing the recovery rate of manganese. In addition, the higher the temperature, the easier it is for manganese to be oxidized.

[0073] The manganese leaching process also has an important impact on the manganese recovery cost. In the manganese leaching process, the higher the amount of sulfuric acid used, the better. With the increase in the amount of sulfuric acid, on the one hand, the content of various impurities in the manganese solution will increase, and on the other hand, this will increase the amount of sulfidizing agent used in the subsequent manganese solution purification process.

[0074] In the impurity removal process of manganese liquid, which sulfiding agent is used and whether one step or multiple steps of impurity removal are used is determined according to the purpose of the manganese liquid. However, it should be noted that the amount of barium sulfide should not be too large, otherwise manganese will be hydrolyzed. The amount of sodium fumer can be determined according to the standards and application fields of manganese-related products. Regarding the impurity removal process, a detailed explanation has been given in the comparative example.

[0075] In all embodiments of the present invention, the recovery rate of manganese can be stabilized at more than 90%, and the process flow is simple and the cost is low.

[0076] The present invention illustrates the detailed structural features of the present invention through the above embodiments, but the present invention is not limited to the above detailed structural features, that is, it does not mean that the present invention must rely on the above detailed structural features to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of the components selected by the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

[0077] The preferred embodiments of the present invention are described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, a variety of simple modifications can be made to the technical solution of the present invention, and these simple modifications all belong to the protection scope of the present invention.

[0078] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0079] In addition, various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A method for recovering manganese from laterite nickel ore, characterized in that: The steps include: (1) introducing CO2 gas into the supernatant of nickel-cobalt precipitation of laterite nickel ore, and adjusting the pH of the solution to 6.0-7.0 to carry out precipitation reaction, and after the precipitation reaction is completed, obtaining a precipitate containing manganese carbonate by solid-liquid separation; (2) mixing the precipitate containing manganese carbonate with water to obtain a suspension, adjusting the pH of the suspension to 0.5 to 6.0 for leaching reaction, and after the leaching reaction is completed, obtaining a manganese-containing leaching solution by solid-liquid separation; (3) adding different sulfides to the manganese-containing leaching solution for impurity removal, controlling the pH value during the impurity removal process not to exceed 7.0, and obtaining a manganese recovery solution through solid-liquid separation after the impurity removal process is completed.

2. The method for recovering manganese from laterite nickel ore according to claim 1, characterized in that: In the supernatant of the laterite nickel ore precipitation of nickel and cobalt in step (1), Mn 1-2 g / L, Ni 0-0.003 g / L, Co 0-0.004 g / L, Fe 0-0.001 g / L, Al 0-0.0015 g / L, Cu 0-0.002 g / L, Zn 0-0.003 g / L, Ca 0.5-0.7 g / L, and Mg 5-7 g / L are contained.

3. The method for recovering manganese from laterite nickel ore according to claim 1, characterized in that: The flow rate of CO2 gas introduced in step (1) is 10 to 300 L / h.

4. The method for recovering manganese from laterite nickel ore according to claim 1, characterized in that: The specific step of adjusting the pH value of the solution to 6.0-7.0 in step (1) comprises: adjusting the pH value of the solution by adding an alkaline substance, wherein the alkaline substance comprises at least one of calcium carbonate, calcium oxide, calcium hydroxide or sodium hydroxide.

5. The method for recovering manganese from laterite nickel ore according to claim 1, characterized in that: In step (1), the precipitation reaction time is 0.5 to 8 hours, and the precipitation reaction temperature is 25 to 90°C.

6. The method for recovering manganese from laterite nickel ore according to claim 1, characterized in that: In step (2), the precipitate containing manganese carbonate and water are mixed in a solid-liquid mass ratio of 1:1 to 10.

7. The method for recovering manganese from laterite nickel ore according to claim 1, characterized in that: The specific step of adjusting the pH of the suspension to 0.5-6.0 in step (2) includes: adjusting the pH of the suspension by adding an acidic substance, wherein the acidic substance includes at least one of hydrochloric acid, sulfuric acid or nitric acid.

8. The method for recovering manganese from laterite nickel ore according to claim 1, characterized in that: In step (2), the temperature of the leaching reaction is 25 to 90° C., and the time of the leaching reaction is 0.1 to 6 hours.

9. The method for recovering manganese from laterite nickel ore according to claim 1, characterized in that: In step (3), each of the sulfides is mixed with the manganese-containing leaching solution in a solid-liquid mass ratio of 1 to 5000:100000, and the sulfide includes at least one of sodium thiamethoxam, manganese sulfide, ammonium sulfide or barium sulfide.

10. The method for recovering manganese from laterite nickel ore according to claim 1, characterized in that: The time for the impurity removal treatment in step (3) is 0.1 to 10 hours.

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