Method for selectively removing manganese in hydrometallurgy process

Abstract

The invention discloses a method for selectively removing manganese in a hydrometallurgy process. The method comprises the following steps: 1) introducing an SO2 / O2 mixed oxidant into a manganese-containing solution to carry out aeration oxidation on the manganese-containing solution; (2) one or more of oxides, hydroxides or carbonates corresponding to alkali metal elements in the manganese-containing solution are used as neutralizers, the pH value of the manganese-containing solution is adjusted, and the pH value is controlled within the acid environment; (3) stirring is controlled, and the SO2 / O2 mixed oxidizing agent and the manganese-containing solution are fully mixed; and 4) controlling the reaction temperature to be room temperature, reacting for a preset time, and filtering to obtain manganese-removed liquid and manganese slag. According to the method, the selectivity of the oxidizing agent is guaranteed to the maximum extent, the reaction conditions are improved on the basis, the reaction conditions are milder, the manganese removal efficiency is high, and the problem that the selectivity and the manganese removal efficiency of an existing manganese removal process cannot be achieved at the same time is solved.

Description

Technical Field

[0001] The invention relates to the technical field of hydrometallurgy, and in particular to a method for selectively removing manganese in a hydrometallurgical process. Background Art

[0002] Manganese is a reddish-grey metal with an abundance of about 0.095% in the earth's crust, ranking 12th among all elements. Manganese is often associated with metals such as nickel and cobalt, and because of its similar chemical properties to the latter, it is easy to enter the leachate together with valuable metals such as nickel and cobalt in the hydrometallurgical leaching process, becoming a common impurity element. Although the hydrometallurgical processes of different metals have different requirements for the manganese content, for example, in the hydrometallurgical process of zinc, appropriate manganese can extend the life of the electrode and improve the electrode efficiency of the electrolytic process. However, in the hydrometallurgy of nickel-cobalt ore, the manganese concentration needs to be strictly controlled to reduce its impact on precipitation, extraction and other processes.

[0003] Commonly used manganese removal methods include two categories, namely physical methods and chemical methods. Solvent extraction, sulfide precipitation, hydroxide precipitation and oxidation precipitation are common chemical manganese removal methods, while physical manganese removal methods mainly include ion exchange, coagulation / flocculation, membrane separation and adsorption. Physical manganese removal methods can generally reduce Mn to extremely low levels and are widely used in wastewater or groundwater treatment, but they are not very suitable for hydrometallurgical systems with Mn concentrations of more than 10g / L. Hydrometallurgy mainly uses chemical methods to remove Mn. Among them, hydroxide precipitation often requires a higher pH to ensure that Mn is reduced to a lower level. At this time, the loss of valuable metals is very large, and it is generally not used as the main means. Sulfide precipitation mainly uses MnS and other metal ions (Cu 2+ 、Ni 2+ 、Co 2+ 、Zn 2+ The process involves sulfides (H2S, Na2S or (NH4)2S), so the process has high requirements for equipment and safety, resulting in high costs. The reaction is very rapid, and the amount of sulfide needs to be precisely controlled, so it also has high requirements for operation. Solvent extraction uses the difference in the solubility of different ions in the liquid phase and the extractant to achieve the separation purpose. Solvent extraction can quickly separate impurity metal ions, but it often requires the selection of specific extractants and strict extraction conditions to obtain better separation effects. In addition, this process faces the problem of poor stability of the extractant when extracting high-valent metal ions. Therefore, it is necessary to add a reduction step before manganese removal, which increases costs and equipment investment. The oxidative manganese removal process uses the characteristic of lower pH of high-valent manganese ion precipitation to reduce the Mn 2+Oxidizing to a higher valence state can achieve the purpose of removing manganese under acidic conditions (pH 3.0-5.0). It not only greatly reduces the amount of neutralizer used but also prevents the co-precipitation loss of valuable metals. It is one of the most promising processes among many manganese removal processes.

[0004] With the development trend of low-carbon, environmental protection, energy conservation and consumption reduction in hydrometallurgy, the requirements for manganese removal technology have become more stringent. It needs to meet the characteristics of low investment and operating costs, high manganese removal efficiency, less loss of valuable metals, and user and environmental friendliness in order to better serve the metallurgical industry. Therefore, it is imperative to develop a new process for highly selective and efficient manganese removal.

[0005] The patent (application publication number CN 110438339 A) proposes a method for removing manganese from nickel-cobalt hydroxide solution, which uses SO2 as a manganese precipitation reagent and nickel carbonate as a neutralizer. After manganese precipitation, air is used to remove free SO2, and the manganese-removed liquid and manganese slag are filtered to effectively remove manganese from the nickel-cobalt hydroxide solution. However, the reaction temperature of this process is relatively high (90-110°C) and the reaction time is relatively long (4-6h). There is still much room for improvement in terms of operating cost and manganese removal efficiency.

[0006] The patent (application publication number CN 111018178 A) discloses a method for removing manganese ions from an acidic solution using ozone. By adding a hydroxyl radical inhibitor before the introduction of ozone, the utilization rate of ozone is increased to achieve the effect of oxidative manganese removal. The oxidizing property of ozone is very strong, so the rate of oxidative manganese removal is very fast, but it is necessary to ensure that there are no other elements that compete with manganese for oxidation, that is, variable valence metal elements, in the solution, and common valuable elements such as nickel and cobalt are all variable valence elements. Therefore, it is foreseeable that in a system where multiple elements coexist in hydrometallurgy, selectivity problems are likely to be faced. In addition, the preparation of ozone requires a special generator, and the process cost is also an important problem that needs to be solved.

[0007] The patent (patent publication number US 6391270B1) provides a method for removing manganese from zinc leachate using a sulfite and O2 composite oxidant, wherein the manganese in the solution is oxidized to a high-valent manganese hydroxide or oxide in a reactor with a good stirring effect at a temperature of 60-90°C and a pH of 4.0-4.6, and then liquid-solid separation is performed to finally achieve the effect of removing manganese from the leachate. Although the patent fully considers the production conditions on site and selects a process that is highly adaptable to the on-site slurry state, the applicability of temperature and pH to non-ferrous metal impurity removal systems other than zinc is questionable, and selectivity is still an issue that needs to be fully considered.

[0008] It can be seen that the above methods have their own advantages, but they all have some limitations to a greater or lesser extent. Therefore, it is particularly important to develop new and efficient manganese removal technologies. Summary of the invention

[0009] The present invention aims to provide a method for selective manganese removal in a hydrometallurgical process, so as to solve the technical problem that the selectivity and manganese removal efficiency of the existing manganese removal process cannot be taken into account at the same time.

[0010] In order to achieve the above-mentioned object, according to one aspect of the present invention, a method for selective manganese removal in a hydrometallurgical process is provided. The method comprises the following steps: 1) introducing a SO2 / O2 mixed oxidant into a manganese-containing solution to aerate and oxidize the manganese-containing solution; 2) using one or more oxides, hydroxides or carbonates corresponding to the alkali metal elements in the manganese-containing solution as a neutralizer to adjust the pH of the manganese-containing solution, and the pH value is controlled within an acidic environment; 3) controlling stirring to fully mix the SO2 / O2 mixed oxidant with the manganese-containing solution; and 4) controlling the reaction temperature to room temperature, and filtering to obtain a manganese-removed liquid and manganese slag after a predetermined reaction time.

[0011] Furthermore, in step 1), the SO2 of the SO2 / O2 mixed oxidant is provided in one or more forms of pure SO2 gas, flue gas containing SO2, sulfite, pyrosulfite or bisulfite.

[0012] Furthermore, in step 1), O2 of the SO2 / O2 mixed oxidant is provided in one or more forms of pure oxygen, air or flue gas.

[0013] Furthermore, in step 1), SO2 and O2 are added in a mixed manner or separately.

[0014] Furthermore, when SO2 and O2 are added in the form of gas, the SO2 flow rate / O2 flow rate ratio is less than 1 / 5.

[0015] Furthermore, in step 2), the neutralizing agent is an alkali metal oxide, hydroxide powder or an aqueous solution thereof; preferably, the neutralizing agent is an active magnesium oxide slurry and / or a sodium hydroxide solution.

[0016] Further, in step 3), the propeller used for stirring is a turbine propeller, a flat-blade propeller, a pitched-blade propeller or a propeller; preferably, the rotation speed of the turbine propeller is 1000-1200 rpm rpm; preferably, the selective manganese removal is carried out in a reactor, and the reactor includes an aeration disk, a baffle and a stirring propeller, and more preferably, the stirring propeller is a downward pressure stirring propeller.

[0017] Furthermore, in step 4), the predetermined time is 1 to 2 hours.

[0018] Further, in step 3), the pH of the manganese-containing solution is controlled at ˜3.5.

[0019] Furthermore, the liquid after manganese removal enters the hydrometallurgical process, and the manganese slag is deeply utilized as a secondary resource for extracting manganese elements.

[0020] The technical solution of the present invention is applied, SO2 / O2 is used as an oxidant, and the oxide, hydroxide or carbonate corresponding to the alkali metal of the solution is used as a neutralizer, and the manganese-containing solution is aerated and oxidized at room temperature and in an acidic environment. The oxidized solution is subjected to liquid-solid separation to obtain a manganese-removed liquid and manganese slag, so that the manganese in the solution can be removed. The present application guarantees the selectivity of the oxidant to the maximum extent, and on this basis improves the reaction conditions, making the reaction conditions milder and the manganese removal efficiency higher, solving the problem that the selectivity and manganese removal efficiency of the existing manganese removal process cannot be achieved at the same time. DETAILED DESCRIPTION

[0021] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be described in detail below in conjunction with the embodiments.

[0022] As described in the background technology, manganese, as a common impurity element in hydrometallurgy, has always been an important topic of hydrometallurgical impurity removal process. The chemical properties of manganese are very similar to those of the main valuable metals nickel, cobalt, copper, and zinc, so that the manganese removal process is often accompanied by the loss of the main metal, and the selectivity of the process is often poor, the main valuable metal loss is large, and the recovery rate is not ideal. The oxidative manganese removal process with gas participation has shown great potential in terms of economy, operability, manganese removal efficiency, and manganese removal depth. It is currently the most ideal existing manganese removal process, but in the manganese removal process, it is limited by factors such as gas dissolution rate, oxidant oxidation capacity, reaction temperature, solution pH, etc., and the manganese removal rate is far from reaching the expected effect, and it is difficult to meet actual production needs.

[0023] In response to the above technical problems, the present application provides a hydrometallurgical manganese removal process with easily available oxidants, relatively mild reaction conditions (can be carried out at room temperature), considerable manganese removal efficiency and good selectivity, which solves the problem that the selectivity and manganese removal efficiency of existing manganese removal processes cannot be taken into account at the same time. At the same time, the manganese removal product obtained can be used as an important secondary resource, creating favorable conditions for the recycling of manganese.

[0024] According to a typical embodiment of the present application, a method for selective manganese removal in a hydrometallurgical process is provided. The method comprises the following steps: 1) introducing a SO2 / O2 mixed oxidant into a manganese-containing solution to aerate and oxidize the manganese-containing solution; 2) using one or more oxides, hydroxides or carbonates corresponding to the alkali metal elements in the manganese-containing solution as a neutralizer to adjust the pH of the manganese-containing solution, and the pH value is controlled within an acidic environment; 3) controlling stirring to fully mix the SO2 / O2 mixed oxidant with the manganese-containing solution; and 4) controlling the reaction temperature to room temperature, and filtering to obtain a manganese-removed liquid and manganese slag after a predetermined reaction time.

[0025] By using the technical solution of the present invention, SO2 / O2 is used as an oxidant, and the oxide, hydroxide or carbonate corresponding to the alkali metal in the solution is used as a neutralizer, and aeration oxidation is performed on the manganese-containing solution at room temperature and in an acidic environment, Mn can be efficiently converted to 2+ Oxidized to MnO2, and then by adjusting the pH value and adding a neutralizing agent, the precipitation of MnO2 is promoted, thereby achieving effective manganese removal from a manganese-containing solution. This process is not only simple to operate, but also has a high processing efficiency, and can achieve an ideal manganese removal effect in a relatively short period of time. The present application guarantees the selectivity of the oxidant to the greatest extent, and on this basis improves the reaction conditions, making the reaction conditions milder, and the manganese removal efficiency is higher, solving the problem that the selectivity and manganese removal efficiency of the existing manganese removal process cannot be achieved at the same time. This process can be widely used in water treatment and metal refining industries, can effectively remove manganese ions in water, improve water quality, and at the same time in the metal refining process, help to improve metal purity.

[0026] In one embodiment of the application, a manganese-containing solution is aerated using a SO2 / O2 mixed oxidant, SO2 can be a gas or flue gas that directly provides SO2, or a compound that provides sulfite ions or bisulfite ions in the solution; O2 can be pure oxygen, or oxygen-enriched or air, flue gas, etc. that can provide O2. Typically, in step 1), SO2 of the SO2 / O2 mixed oxidant is provided in the form of one or more of pure SO2 gas, flue gas containing SO2, sulfite, pyrosulfite, or bisulfite, and O2 of the SO2 / O2 mixed oxidant is provided in the form of one or more of pure oxygen, air, or flue gas.

[0027] In one embodiment of the application, SO2 and O2 can be added in step 1) by mixing or separately. When added in the form of gas, the SO2 flow rate / O2 flow rate ratio is less than 1 / 5, and the introduction can be carried out by or without enhanced dispersion. Among them, the enhanced dispersion method refers to mixing the gas with the solution in the form of tiny and dispersed bubbles, which can generally be achieved by aeration plates, venturi tubes, micro-nano bubble generators and other devices that can obtain tiny bubbles. The present application can achieve Mn by optimizing the flow ratio of SO2 to O2. 2+Efficient oxidation of SO2 can be achieved while avoiding excessive use of SO2 and reducing pollution to the environment. In areas with strict environmental protection requirements, this flow ratio control can help industrial wastewater treatment meet more stringent emission standards. Among them, in one embodiment of the application, SO2 and O2 can be added to the manganese-containing solution uniformly after mixing. This mixing method can ensure the uniform distribution of the oxidant and improve the uniformity and efficiency of the reaction. In industrial scenarios where a large amount of manganese-containing solution needs to be treated, such as smelting wastewater treatment, this mixing method can improve the continuity and stability of the treatment. In another embodiment of the application, SO2 and O2 can also be added to the manganese-containing solution separately using independent pipes. The use of independent pipes can more flexibly control the flow of the two gases to meet the treatment requirements of manganese-containing solutions of different concentrations. In scenarios where fine control of gas flow is required, this independent pipe design can provide higher operating accuracy.

[0028] According to a typical embodiment of the present application, in step 2), the neutralizing agent is an alkali metal oxide, hydroxide powder or an aqueous solution thereof; for example, the neutralizing agent is an active magnesium oxide slurry and / or a sodium hydroxide solution, and its concentration is determined according to the initial pH value of the manganese-containing solution and the Mn 2+ The concentration can be adjusted. By precisely controlling the concentration of the neutralizer, the precipitation of MnO2 can be more effectively promoted, unnecessary chemical consumption can be reduced, and the treatment efficiency can be improved. In one embodiment of the present application, sodium hydroxide is used as a neutralizer, which can not only effectively adjust the pH value and promote the precipitation of MnO2, but also has a strong buffering capacity, can maintain the stability of the pH value, and improve the treatment effect. In scenarios where a stable pH value is required, the use of sodium hydroxide can ensure the safety and stability of water quality.

[0029] According to a typical embodiment of the present application, in step 3), the propeller type used for stirring is a turbine propeller, a flat-blade propeller, a pitched-blade propeller or a propeller; preferably, the speed of the turbine propeller is 1000-1200rpm. High-speed stirring can further enhance the gas-liquid mixing effect, improve the reaction rate and manganese removal efficiency. In scenarios where a large amount of manganese-containing solution needs to be quickly processed, such as industrial wastewater treatment plants, this stirring device can significantly improve the processing capacity. However, individual higher speeds such as 1500rpm will lead to a deterioration in the manganese removal effect. At too low a speed, such as below 500rpm, the gas cannot be well dispersed, and the manganese removal effect is not good.

[0030] Preferably, the selective manganese removal is carried out in a reactor, the reactor includes an aeration disk, a baffle and a stirring paddle, and more preferably, the stirring paddle is a downward pressure stirring paddle; in one embodiment of the present application, the reactor is a stirring tank with efficient gas-liquid mixing ability, and the efficient gas-liquid mixing ability can ensure that the SO2 / O2 mixed oxidant is fully in contact with the manganese-containing solution, improve the oxidation efficiency, and shorten the processing time. This reactor has significant advantages in the chemical industry for treating wastewater containing high concentrations of manganese ions.

[0031] According to a typical implementation of the present application, in step 4), the predetermined time is 1 to 2 hours, and the reaction temperature is room temperature. Under mild reaction conditions, not only can the manganese removal effect be guaranteed, but also energy consumption can be reduced and economic benefits can be improved. Such mild reaction conditions are easy to implement in water treatment facilities of various sizes, reducing the difficulty and cost of operation.

[0032] According to a typical embodiment of the present application, in step 3), the pH of the manganese-containing solution is controlled at 3.5 to 4.5. Within this pH range, the precipitation effect of MnO2 is optimal, and effective removal of manganese ions can be achieved while avoiding interference with other metal ions. In the hydrometallurgical process of metal minerals, this pH control can improve the recovery rate and purity of the metal.

[0033] Centrifugal separation technology can efficiently separate solid particles in the solution, improve the recovery rate of manganese slag, and reduce solid waste in the treatment process. In the scenario where manganese slag needs to be recycled as a resource for reuse, the application of centrifugal separation technology can improve the recycling rate of resources. According to a typical implementation of the present application, the liquid after manganese removal enters the hydrometallurgical process, and the manganese slag is deeply utilized as a secondary resource for extracting manganese elements. In an embodiment of the present application, the manganese slag recycling step includes converting MnO2 in the manganese slag into high-purity MnO by high-temperature calcination. The recycling of manganese slag can not only reduce waste emissions, but also convert MnO2 into high-purity MnO, which can be used as a raw material for catalysts or battery materials to achieve the recycling of resources. Driven by resource recovery and circular economy, this manganese slag recycling step can bring new economic benefits and environmental protection value to industrial wastewater treatment.

[0034] The beneficial effects of the present invention will be further described below in conjunction with embodiments.

[0035] Example 1

[0036] The SO2 / O2 oxidation and manganese removal process of this embodiment is as follows:

[0037] The copper extraction liquid (hereinafter referred to as the extracting mother liquid) of a copper smelter was used as the object for manganese removal, in which Co 2+ 2.39g / L, Mn 2+ 2.23g / L, except Co 2+ , Mn 2+ Other elements are hardly oxidized; the raffinate mother liquor itself contains Mg 2+ Therefore, 10% active magnesium oxide slurry was used as a neutralizer to control the influence of impurity ions on the test results.

[0038] Take 1L of the raffinate mother liquor and place it in a beaker. Put a baffle to make the solution in the beaker mix more fully. Use a turbine propeller to stir at a speed of 1200 rpm. Pass SO2 / O2 mixed gas into the solution, control the SO2 flow rate to 30mL / min, and the O2 flow rate to 200mL / min. During the reaction, control the temperature to room temperature and pH 3.5. React for 2h, then filter, and measure the filtrate Co 2+ Content 2.17g / L, Mn 2+ Content 0.60g / L, washing liquid Co 2+ Content 0.10g / L, Mn 2+ Content 0.04g / L, get Co 2+ The liquid meter loss rate is only about 1.85%, while Mn 2+ The liquid meter removal rate is as high as 70.56%, and the average manganese removal rate is as high as 0.79g / (L·h).

[0039] Example 2

[0040] Use Co 2+ 2.39g / L, Mn 2+ 2.22g / L of a copper smelter's raffinate mother liquor, control the SO2 and O2 flow rates to 20mL / min and 200mL / min respectively, and control the solution pH 3.5, time 2h, temperature room temperature, 10wt% active magnesium oxide as a neutralizer during the reaction process, and then filter it. The filtrate Co 2+ Content 2.11g / L, Mn 2+ Content 0.97g / L, washing liquid Co 2+ Content 0.08g / L, Mn 2+ Content 0.05g / L, Co 2+ The liquid meter loss rate is ~1.56%, and Mn 2+ The liquid meter removal rate is 50.92%, and the average manganese removal rate is as high as 0.57g / (L·h).

[0041] Example 3

[0042] Use Co 2+ 2.21g / L, Mn 2+ 2.07g / L of a copper smelter's raffinate mother liquor 1L, using sodium pyrosulfite + air mixed solution treatment, sodium pyrosulfite dosage 10g, air flow 1L / min, control the solution pH 3.5, time 1h, temperature room temperature, 10wt% active magnesium oxide as a neutralizer during the reaction process, and then filtered, measured, the filtrate Co 2+ Content 2.00g / L, Mn 2+ Content 1.11g / L, washing liquid Co 2+ Content 0.08g / L, Mn 2+Content 0.05g / L, Co 2+ There is almost no loss, and Mn 2+ The liquid meter removal rate is high, 40.27%, and the average manganese removal rate is as high as 0.83g / (L·h).

[0043] Example 4

[0044] Use Co 2+ 2.21g / L, Mn 2+ 2.07g / L of a copper smelter's raffinate mother liquor 1L, using sodium pyrosulfite + air mixed solution treatment, sodium pyrosulfite dosage 15g, air flow 1L / min, control the solution pH 3.5, time 1h, temperature room temperature, 10wt% active magnesium oxide as a neutralizer during the reaction process, and then filtered, measured, the filtrate Co 2+ Content 1.95g / L, Mn 2+ Content 1.03g / L, washing liquid Co 2+ Content 0.08g / L, Mn 2+ Content 0.05g / L, Co 2+ The liquid meter loss rate is 0.11%, and Mn 2+ The liquid meter removal rate is high, 42.96%, and the average manganese removal rate is as high as 0.89g / (L·h).

[0045] Comparative Example 1

[0046] Use Co 2+ 2.30g / L, Mn 2+ 2.11g / L of a copper smelter's raffinate mother liquor 1L, use SO2 / air mixed solution treatment, SO2 flow rate 100mL / min, air flow rate 1L / min, at this time SO2 / O2 is about 1 / 2, control the solution pH 3.5, time 2h, temperature room temperature, 10wt% active magnesium oxide as neutralizer during the reaction process, and then filter, measured, filtrate Co 2+ Content 1.65g / L, Mn 2+ Content 0.50g / L, washing liquid Co 2+ Content 0.09g / L, Mn 2+ Content 0.04g / L, Co 2+ The liquid meter loss rate is as high as 5.97%, and Mn 2+ The liquid meter removal rate is 68.60%, and the average manganese removal rate is as high as 0.73g / (L·h).

[0047] Comparative Example 2

[0048] Use Co 2+ 2.21g / L, Mn 2+2.03g / L of a copper smelter's raffinate mother liquor was treated with a SO2 / O2 mixed solution, with a SO2 flow rate of 30mL / min and an O2 flow rate of 200mL / min. The pH of the solution was controlled at 3.5, the reaction time was 6h, the temperature was room temperature, and 10wt% active magnesium oxide was used as a neutralizer. The filtrate was then filtered and measured to be Co 2+ Content 1.43g / L, Mn 2+ Content 0.048g / L, washing liquid Co 2+ Content 0.08g / L, Mn 2+ Content 0.0046g / L, Co 2+ The liquid meter loss rate is as high as 23.16%, and Mn 2+ The liquid meter removal rate is 97.12%, and the average manganese removal rate is as high as 0.33g / (L·h).

[0049] Comparative Example 3

[0050] Use Co 2+ 2.37g / L, Mn 2+ 2.14g / L of a copper smelter's raffinate mother liquor 1L, use SO2 / O2 mixed solution treatment, SO2 flow rate 20mL / min, O2 flow rate 200mL / min, control the solution pH 2.5, time 2h, temperature room temperature, 10wt% active magnesium oxide as neutralizer during the reaction process, and then filter, measured, filtrate Co 2+ Content 1.91g / L, Mn 2+ Content 1.27g / L, washing liquid Co 2+ Content 0.046g / L, Mn 2+ Content 0.036g / L, Co 2+ The liquid meter loss rate is as high as 19.23%, and Mn 2+ The liquid meter removal rate is 40.30%, and the average manganese removal rate is as high as 0.43g / (L·h).

[0051] Comparative Example 4

[0052] Use Co 2+ 2.39g / L, Mn 2+ 2.11g / L of a copper smelter's raffinate mother liquor 1L, using sodium pyrosulfite / air mixed solution treatment, sodium pyrosulfite dosage 15g, air flow 1L / min, control the solution pH 3.5, time 1h, temperature 80℃, 10wt% active magnesium oxide as neutralizer during the reaction process, and then filtered, measured, filtrate Co 2+ Content 1.97g / L, Mn 2+ Content 1.40g / L, washing liquid Co 2+ Content 0.07g / L, Mn 2+ Content 0.05g / L, Co2+ The liquid meter loss rate is as high as 12.60%, and Mn 2+ The liquid meter removal rate is 34.41%, and the average manganese removal rate is as high as 0.78g / (L·h).

[0053] Comparative Example 5

[0054] The same as Example 1, except that O2 was introduced into the manganese-containing solution as an oxidant, and the O2 flow rate was 1000 mL / min. The filtrate Co 2+ Content 2.09g / L, Mn 2+ Content 1.95g / L, washing liquid Co 2+ Content 0.05g / L, Mn 2+ Content 0.05g / L, get Co 2+ The liquid meter loss rate is about 0.81%, while Mn 2+ The liquid meter removal rate is 1.34%, and the average manganese removal rate is 0.03g / (L·h).

[0055] Comparative Example 6

[0056] The same as Example 1, except that the neutralizer is 10wt% sodium hydroxide solution, and the filtrate Co is measured. 2+ Content 1.36g / L, Mn 2+ Content 0.11g / L, washing liquid Co 2+ Content 0.08g / L, Mn 2+ Content 0.01g / L, get Co 2+ The liquid meter loss rate is about 22.82%, and Mn 2+ The liquid meter removal rate is 93.17%, and the average manganese removal rate is 0.33g / (L·h).

[0057] Comparative Example 7

[0058] The same as Example 1, except that the reaction temperature was controlled at room temperature and pH 5.0, the reaction was carried out for 2 h, and then filtered to obtain the filtrate Co 2+ Content 0.32g / L, Mn 2+ Content 0.02g / L, washing liquid Co 2+ Content 0.01g / L, Mn 2+ Content 0.0003g / L, get Co 2+ The liquid meter loss rate is about 87.28%, while Mn 2+ The liquid meter removal rate is as high as 98.96%, and the average manganese removal rate is as high as 1.09g / (L·h).

[0059] Comparative Example 8

[0060] The same as Example 1, except that the reaction temperature was controlled at room temperature and pH 4.0, the reaction was carried out for 2 h, and then filtered to obtain the filtrate Co 2+ Content 1.76g / L, Mn 2+ Content 0.02g / L, washing liquid Co 2+ Content 0.18g / L, Mn 2+ Content 0.002g / L, get Co 2+ The liquid meter loss rate is about 26.53%, and Mn 2+ The liquid meter removal rate is as high as 99.39%, and the average manganese removal rate is as high as 1.10g / (L·h).

[0061] Comparison of Examples 1 to 4 with Comparative Examples 1 to 4:

[0062] 1. The flow ratio of SO2 to O2 mainly affects the strength and rate of oxidation. When the SO2 / O2 ratio is small, the oxidation is strong, but the oxidation rate is slow. When the SO2 / O2 ratio is large, the oxidation becomes weaker, but the oxidation rate may increase. 2+ The oxidation requires more oxidizing properties than Co 2+ Slightly lower, so the main purpose of controlling the SO2 / O2 ratio is to find a solution that can effectively oxidize Mn 2+ Co is less oxidized or even not oxidized 2+ The oxidation capacity can be improved while obtaining a high oxidation rate.

[0063] 2. Reaction time is crucial to manganese removal efficiency. Although a long reaction time (such as 6 h in Comparative Example 2) can improve the removal rate of manganese, it will also lead to a large loss of cobalt, which is contrary to the goal of pursuing high efficiency and selectivity in actual production.

[0064] 3. The pH at which metal ions in the solution begin to precipitate is fixed (value or range). This application mainly utilizes the characteristic that the pH at which high-valent metal ions begin to precipitate is significantly lower than that of low-valent metal ions. An oxidant is added to oxidize low-valent metal ions into high-valent ones, and the pH is controlled at the same time to achieve the purpose of removing precipitated ions from the solution.

[0065] 4. Temperature has an effect on the reaction rate, but high temperature (such as 80° C. in Comparative Example 4) may aggravate the side reactions of valuable metals, resulting in increased loss of cobalt.

[0066] From the above description, it can be seen that the above embodiments of the present invention achieve the following technical effects: using SO2 / O2 as an oxidant and the oxide or hydroxide or carbonate corresponding to the alkali metal of the solution as a neutralizer, aeration oxidation is performed on the manganese-containing solution at room temperature and in an acidic environment, and the oxidized solution is subjected to liquid-solid separation to obtain a manganese-free liquid and manganese slag, so that the manganese in the solution can be removed. The present application guarantees the selectivity of the oxidant to the maximum extent, and on this basis improves the reaction conditions, making the reaction conditions milder and the manganese removal efficiency higher, solving the problem that the selectivity and manganese removal efficiency of the existing manganese removal process cannot be achieved at the same time.

[0067] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for selectively removing manganese in a hydrometallurgical process, characterized in that: The following steps are involved: 1) introducing a mixed oxidant of SO2 / O2 into a manganese-containing solution to aerate and oxidize the manganese-containing solution; 2) using one or more oxides, hydroxides or carbonates corresponding to the alkali metal element in the manganese-containing solution as a neutralizing agent to adjust the pH of the manganese-containing solution, wherein the pH value is controlled within an acidic environment; 3) controlling stirring to fully mix the SO2 / O2 mixed oxidant with the manganese-containing solution; and 4) Controlling the reaction temperature to be room temperature, and after the reaction time is set, filtering to obtain the manganese-free liquid and manganese slag.

2. The method according to claim 1, characterized in that In the step 1), the SO2 of the SO2 / O2 mixed oxidant is provided in one or more forms of pure SO2 gas, flue gas containing SO2, sulfite, pyrosulfite or bisulfite.

3. The method according to claim 1, characterized in that In the step 1), the O2 of the SO2 / O2 mixed oxidant is provided in one or more forms of pure oxygen, air or flue gas.

4. The method according to any one of claims 1 to 3, characterized in that In the step 1), SO2 and O2 are added in a mixed manner or separately.

5. The method according to claim 4, characterized in that When the SO2 and O2 are added in the form of gas, the SO2 flow rate / O2 flow rate ratio is less than 1 / 5.

6. The method according to any one of claims 1 to 3, characterized in that In the step 2), the neutralizing agent is an alkali metal oxide, hydroxide powder or an aqueous solution thereof; Preferably, the neutralizing agent is active magnesium oxide slurry and / or sodium hydroxide solution.

7. The method according to any one of claims 1 to 3, characterized in that In the step 3), the propeller used for stirring is a turbine propeller, a flat-blade propeller, a pitched-blade propeller or a propeller; Preferably, the speed of the turbine propeller is 1000-1200 rpm; Preferably, the selective manganese removal is carried out in a reactor, and the reactor comprises an aeration plate, a baffle and a stirring paddle. More preferably, the stirring paddle is a downward pressure stirring paddle.

8. The method according to any one of claims 1 to 3, characterized in that In the step 4), the predetermined time is 1 to 2 hours.

9. The method according to any one of claims 1 to 3, characterized in that In the step 3), the pH of the manganese-containing solution is controlled at ∼3.

5.

10. The method according to any one of claims 1 to 3, characterized in that The liquid after manganese removal enters the hydrometallurgical process, and the manganese slag is deeply utilized as a secondary resource for extracting manganese elements.