Resource treatment method for manganese-containing wastewater

Abstract

The invention provides a resource treatment method for manganese-containing wastewater, which comprises the following steps: S1, adding an alkaline regulator into the manganese-containing wastewater to obtain a first treatment solution with the pH value of 9.3-9.65; the manganese-containing wastewater contains manganese ions, calcium ions and magnesium ions, the concentration of the manganese ions is 80-500 mg / L, and the mass of the manganese ions is smaller than that of the calcium ions and that of the magnesium ions; s2, adding a flocculating agent into the first treatment liquid, and carrying out first mixing, so as to obtain a second treatment liquid with the pH value of 9.0-9.5; and S3, adding pypocholoride into the second treatment liquid, carrying out second mixing, and carrying out solid-liquid separation to obtain manganese-containing final precipitate and a manganese-removed water body. According to the invention, calcium and magnesium coprecipitation can be inhibited, and meanwhile, the dosage of the medicament is reduced; and the manganese ions can be selectively and efficiently precipitated, the grade of the manganese precipitate is high, the pH value of the manganese-removed water body is less than 9, and both the manganese ions and residual chlorine do not exceed the standard.

Description

Technical Field

[0001] The present invention relates to the field of wastewater treatment, and in particular to a method for resource treatment of manganese-containing wastewater. Background Art

[0002] The discharge of manganese ore drainage is extremely large, and it shows the characteristics of high-concentration manganese pollution (manganese ion concentration 80-500 mg / L). At the same time, it is rich in calcium, magnesium and other ions, forming a complex multi-ion system. At present, the main method for removing manganese in manganese-containing wastewater is the chemical precipitation method; for example: by adding alkaline regulators such as sodium hydroxide to the manganese-containing wastewater, the precipitation and separation of manganese can be achieved.

[0003] Although the existing chemical precipitation method can achieve the precipitation of manganese ions in manganese-containing wastewater, this method has significant defects under the water quality conditions of typical manganese ore drainage; since the total amount of calcium, magnesium and other ions in manganese ore drainage is usually much larger than that of manganese ions, and they are all prone to form precipitates under alkaline conditions, it is necessary to overdose the alkaline regulator to maintain the precipitation environment in order to maintain a high removal rate of manganese ions.

[0004] However, in this case, a large amount of alkaline regulator will be used, resulting in the synchronous precipitation of a large amount of calcium and magnesium ions. Not only is the waste of reagents serious, but also manganese ions cannot be separated alone, generating solid waste containing calcium and magnesium impurities, presenting a risk of secondary pollution, and affecting the grade of manganese in the precipitate, making it difficult to utilize resources; although sodium fluoride can be used to pre-remove calcium and magnesium, it will further increase the comprehensive cost. At the same time, this method will introduce F - residue, and an additional defluorination process needs to be added in the later stage of treatment, further increasing the comprehensive cost.

[0005] In view of this, it is necessary to provide a method for resource treatment of manganese-containing wastewater to solve or at least alleviate the technical problems of how to inhibit the co-precipitation of calcium and magnesium, reduce the dosage of reagents, and efficiently precipitate manganese ions. Summary of the Invention

[0006] The main object of the present invention is to provide a method for resource treatment of manganese-containing wastewater, aiming to solve the technical problems of inhibiting the co-precipitation of calcium and magnesium, reducing the dosage of reagents, and efficiently precipitating manganese ions.

[0007] To achieve the above object, the present invention provides a method for resource treatment of manganese-containing wastewater, including the steps of: S1, adding an alkaline regulator to the manganese-containing wastewater to obtain a first treatment liquid with a pH of 9.3-9.65; The manganese-containing wastewater contains manganese ions, calcium ions, and magnesium ions; in the manganese-containing wastewater, the concentration of the manganese ions is 80-500 mg / L; the mass of the manganese ions is less than the mass of the calcium and magnesium ions, and the mass of the calcium and magnesium ions is the sum of the masses of the calcium ions and the magnesium ions; S2. Add a flocculant to the first treatment liquid and perform a first mixing to obtain a second treatment liquid with a pH of 9.0 - 9.5; S3. Add a hypochlorite to the second treatment liquid and perform a second mixing, then perform solid - liquid separation to obtain a manganese - containing final precipitate and a manganese - removed water body.

[0008] Further, the alkaline regulator includes one or more of sodium hydroxide, potassium hydroxide, and calcium oxide.

[0009] Further, the flocculant includes one or more of polyacrylamide, polyaluminum chloride, and polyferric sulfate; the mass percentage of the flocculant and the manganese - containing wastewater is 0.1 - 1‰.

[0010] Further, the hypochlorite includes one or more of sodium hypochlorite, potassium hypochlorite, and calcium hypochlorite; the molar ratio of the hypochlorite to the manganese ions in the second treatment liquid is 1.1 - 3.2:1.

[0011] Further, the duration of the first mixing is 40 - 80 min.

[0012] Further, the duration of the second mixing is not less than 20 min.

[0013] Further, step S2 further includes: performing solid - liquid separation on the second treatment liquid to obtain a manganese - containing intermediate precipitate and the second treatment liquid after solid - liquid separation.

[0014] Further, step S3 further includes: after completing the second mixing, adding a part of the manganese - containing intermediate precipitate, and then performing a third mixing; the mass percentage of the part of the manganese - containing intermediate precipitate in the manganese - containing intermediate precipitate is 10 - 30%; the duration of the third mixing is not less than 5 min.

[0015] Further, the molar ratio of the hypochlorite to the manganese ions in the second treatment liquid is 1.1 - 1.8:1.

[0016] Further, in step S2, solid - liquid separation is not performed; the molar ratio of the hypochlorite to the manganese ions in the second treatment liquid is 2.3 - 3.2:1.

[0017] Compared with the prior art, the present invention has at least the following advantages: The present invention can selectively and efficiently precipitate manganese ions, reduce the dosage of chemicals, achieve a high grade of manganese precipitation, maintain the pH of the water body after manganese removal below 9, and ensure that both manganese ions and residual chlorine do not exceed the standards. Specifically, in the chemical precipitation stage, based on the difference in solubility products of manganese, calcium, and magnesium ions, the present invention can inhibit the co-precipitation of calcium and magnesium while reducing the dosage of alkaline regulators, and can efficiently and selectively precipitate manganese ions with a high grade of manganese precipitation. By precisely controlling the pH, the present invention selectively precipitates manganese ions, causing dissolved manganese to mainly form manganese hydroxide while avoiding the simultaneous precipitation of calcium and magnesium. This significantly reduces the dosage of alkaline regulators and remarkably increases the proportion of manganese hydroxide in the precipitate, resulting in a higher grade of manganese that can be recycled.

[0018] In the subsequent oxidation stage, based on the difference in oxidation characteristics of multivalent manganese and calcium / magnesium, the present invention mainly uses hypochlorite for directional deep oxidation of manganese removal. On the one hand, this process hardly produces precipitates of calcium and magnesium but mainly forms manganese oxide, thus obtaining a high-grade manganese precipitate. On the other hand, due to the substantial removal of manganese in the chemical precipitation, the amount of residual manganese ions is small during the oxidation of manganese removal, so the dosage of hypochlorite can be significantly reduced, further avoiding a large increase in the total amount of chemicals and effectively controlling the generation of new pollution during the oxidation treatment process.

[0019] By using hypochlorite as an oxidant, the present invention realizes the synergistic enhancement of the precipitation-oxidation reaction, avoids the step of adding alkali to adjust the solution pH in the traditional oxidation process, and can spontaneously callback the pH to reduce the effluent pH. Since the present invention precisely regulates the pH of the precipitation reaction in the early stage, the oxidation reaction of hypochlorite is in the optimal solution pH condition, improving the oxidation activity without the need to separately adjust the solution pH, and ensuring that both manganese ions and residual chlorine in the effluent meet the standards. At the same time, the oxidation process of hypochlorite can effectively callback the pH, realizing the front-back linkage control of pH, and the acid addition callback link for the effluent of the traditional precipitation process can be cancelled.

[0020] Furthermore, after oxidation, the present invention can recycle through trace manganese-containing intermediate precipitates (manganese hydroxide) for the reuse of oxidation effluent, control the amount of residual chlorine, and improve the effluent quality. In the present invention, since only the manganese-containing intermediate precipitate is reused for the oxidation effluent, there will be no situation where the dosage of hypochlorite increases due to the manganese-containing intermediate precipitate, and it has little impact on the grade of the manganese-containing final precipitate and the process.

[0021] The present invention innovatively establishes a synergistic system of "pH regulation - directional oxidation" and incorporates the idea of "manganese hydroxide internal circulation for chlorine control", achieving the efficient precipitation of manganese ions and the deep purification of manganese in wastewater under the condition of no secondary pollution. Brief Description of the Drawings

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the accompanying drawings required for the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on the structures shown in these drawings.

[0023] Figure 1 XRD pattern of the manganese-containing intermediate precipitate in Embodiment 1 of the present invention; Figure 2 XRD pattern of the manganese-containing final precipitate in Embodiment 1 of the present invention; Figure 3 XRD pattern of the manganese-containing final precipitate in Embodiment 3 of the present invention.

[0024] The realization of the object of the present invention, functional features and advantages will be further described in conjunction with the embodiments with reference to the accompanying drawings. Specific embodiments

[0025] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0026] Moreover, the technical solutions between the various embodiments of the present invention can be combined with each other, but it must be based on the ability of those of ordinary skill in the art to implement. When the combination of technical solutions results in contradictions or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0027] When the embodiment gives a numerical range, it should be understood that unless otherwise specified in the present invention, both endpoints of each numerical range and any value between the two endpoints can be selected. Unless otherwise defined, all technical and scientific terms used in the present invention, based on the understanding of those of ordinary skill in the art of the prior art and the description of the present invention, can also use any methods, devices and materials similar or equivalent to the methods, devices and materials described in the embodiments of the present invention to implement the present invention.

[0028] The present invention provides a method for resource treatment of manganese-containing wastewater, including the steps of: S1, adding an alkaline regulator to the manganese-containing wastewater to obtain a first treatment solution with a pH of 9.3 - 9.65.

[0029] In the present invention, the pH of the first treatment liquid is further 9.3 - 9.6 or 9.55 - 9.65 or 9.55 - 9.62 or 9.58 - 9.62 or 9.3 - 9.5 or 9.3 - 9.4 or 9.4 - 9.5; in the present invention, an alkaline regulator is added to the manganese-containing wastewater to directly adjust the pH of the first treatment liquid.

[0030] In the present invention, the manganese-containing wastewater contains manganese ions, calcium ions, and magnesium ions; in the manganese-containing wastewater, the concentration of the manganese ions is 80 - 500 mg / L, further 80 - 300 mg / L, further 100 - 300 mg / L, further 100 - 200 mg / L or 100 - 150 mg / L or 200 - 300 mg / L; the mass of the manganese ions is less than the mass of the calcium and magnesium ions, and the mass of the calcium and magnesium ions is the sum of the masses of the calcium ions and the magnesium ions; further, the mass ratio of the manganese ions to the calcium and magnesium ions is 1:3 - 10, further 1:6 - 8 or 1:3 - 4.

[0031] Specifically, the manganese-containing wastewater in the present invention is manganese ore water inrush; in the manganese-containing wastewater, the concentration of the calcium ions is 200 - 600 mg / L, further 400 - 600 mg / L, further 400 - 500 mg / L; the concentration of the magnesium ions is 100 - 500 mg / L, further 300 - 500 mg / L, further 300 - 400 mg / L.

[0032] In the present invention, since the manganese ore water inrush contains a large amount of calcium ions and magnesium ions, during the precipitation process using an alkaline regulator, if efficient precipitation of manganese ions is to be achieved, it will inevitably lead to a large amount of precipitation of calcium ions and magnesium ions; therefore, it is necessary to find a suitable reaction point to ensure the preliminary precipitation of manganese ions while not causing a large amount of precipitation of calcium and magnesium ions and being able to adapt to the oxidation process of hypochlorite. In this case, when using hypochlorite for the deep removal of manganese ions, it will not cause excessive use of hypochlorite and excessive residual chlorine, and can adjust the pH back.

[0033] In the present invention, the alkaline regulator includes one or more of sodium hydroxide, potassium hydroxide, and calcium oxide; further, the alkaline regulator includes sodium hydroxide. The molar ratio of the alkaline regulator to the manganese ions in the manganese-containing wastewater is 2.5 - 3.1:1, further 2.6 - 3:1 or 2.6 - 2.8:1 or 2.8 - 3:1 or 2.9 - 3:1 or 2.9 - 3.1:1.

[0034] S2. Add a flocculant to the first treatment liquid and then conduct a first mixing to obtain a second treatment liquid with a pH of 9.0 - 9.5; the pH of the second treatment liquid is further 9.1 - 9.4, further 9.1 - 9.3 or 9.3 - 9.4.

[0035] In the present invention, after obtaining the first treatment liquid, directly add the flocculant to the first treatment liquid and then conduct a first mixing.

[0036] In the present invention, the flocculant includes one or more of polyacrylamide, polyaluminum chloride, and polyferric sulfate; further, the flocculant includes polyacrylamide (PAM). The mass percentage of the flocculant and the manganese-containing wastewater is 0.1 - 1‰, further 0.4 - 1‰, further 0.5 - 1‰ or 0.4 - 0.6‰. In the specific implementation process, the flocculant is added to the first treatment liquid in the form of a flocculant liquid; the mass concentration of the flocculant in the flocculant liquid can be 0.01 - 1%, further 0.05 - 0.15%; the volume percentage of the flocculant liquid and the first treatment liquid can be 0.1 - 5%, further 0.1 - 1%.

[0037] In the present invention, in order to achieve the selective removal of manganese and be more compatible with the subsequent oxidation, the duration of the first mixing is 40 - 80 min, further 50 - 70 min.

[0038] S3. Add hypochlorite to the second treatment liquid and then conduct a second mixing, followed by solid-liquid separation to obtain a manganese-containing final precipitate and a manganese-removed water body (effluent); in the manganese-containing final precipitate of the present invention, manganese mainly exists in the form of an oxide; the pH of the manganese-removed water body is less than 9, further 8.1 - 8.9, further 8.2 - 8.8, further 8.2 - 8.3 or 8.3 - 8.5 or 8.5 - 8.7 or 8.7 - 8.8.

[0039] In the manganese-removed water body, the content of manganese ions is less than 2 mg / L, further less than 0.6 mg / L, further less than 0.5 mg / L; the residual chlorine is less than 0.5 mg / L, further less than 0.3 mg / L, further less than 0.2 mg / L, further less than 0.15 mg / L.

[0040] In the present invention, after obtaining the second treatment liquid, the hypochlorite is directly added to the second treatment liquid and then the second mixing is carried out. In the present invention, the hypochlorite includes one or more of sodium hypochlorite, potassium hypochlorite, and calcium hypochlorite; further, the hypochlorite includes sodium hypochlorite. In the present invention, by using the hypochlorite, the callback of the pH of the water body can be realized, so that the alkalinity of the water body is reduced. In the present invention, the molar ratio of the hypochlorite to the manganese ions in the second treatment liquid is 1.1-3.2:1, further 1.3-3.2:1, further 1.5-3:1 or 1.1-1.8:1 or 1.3-1.8:1 or 2.3-3.2:1 or 1.5-1.6:1 or 2.5-3:1.

[0041] In the present invention, the duration of the second mixing is not less than 20 min; further, the duration of the second mixing is 20-60 min, further 20-40 min or 30-60 min or 30-40 min.

[0042] It should be noted that although the oxidation with hypochlorite can remove manganese; however, if only hypochlorite oxidation is used to remove manganese, the dosage of hypochlorite will be too high, resulting in a sharp increase in chemical agent costs and energy consumption, the high-concentration manganese ions are difficult to be deeply purified, the effluent concentration is likely to exceed the standard, and new pollution risks will be generated, such as excessive residual chlorine. And only using the chemical precipitation method of adding alkali to remove manganese from wastewater containing a large amount of calcium and magnesium at the same time will not only face the problem of a large amount of chemical agents added, but also lead to calcium-magnesium coprecipitation.

[0043] If the two are directly used in combination, it is necessary to overcome the calcium-magnesium coprecipitation during the precipitation process and the problem of how to connect the precipitation manganese removal and the oxidation manganese removal; it should be noted that if the pH after chemical precipitation cannot be adapted to the oxidation of hypochlorite, it will also cause manganese ions and residual chlorine to exceed the standard.

[0044] It should be noted that if there is no difference in removing manganese, calcium, and magnesium, the amount of the alkaline regulator will be inevitably large; since the present invention selectively removes manganese in the early stage, the usage amount of the alkaline regulator can be reduced, and the dosage of the hypochlorite is related to the manganese ion content during deep manganese removal; therefore, the present invention realizes the manganese removal effect under a large amount of chemical agents with a smaller total amount of chemical agents, and can also overcome the problem of calcium-magnesium coprecipitation, improve the grade of manganese precipitation, and callback the pH, and avoid excessive residual chlorine.

[0045] The present invention adopts a precipitation-oxidation synergistic process, firstly, by adding an appropriate amount of alkali and accurately controlling the pH of the solution, the selective precipitation of manganese ions is achieved, and then a small amount of hypochlorite is added to oxidize and remove the residual manganese ions, and the residual chlorine is controlled by coupling "manganese hydroxide internal circulation chlorine control". This method greatly reduces the dosage of the reagent, has low cost, and can simultaneously realize the resource utilization and deep purification of manganese in wastewater such as manganese mine water; the manganese ion recovery rate is large, the recovered manganese is of high purity, and the effluent meets the discharge standards, which has a good industrial application prospect.

[0046] As a supplementary explanation of the present invention: In the step S2 of the present invention, after obtaining the second treatment liquid, solid-liquid separation may be performed or not; if solid-liquid separation is performed, after completing the second mixing, the manganese-containing intermediate precipitate obtained after solid-liquid separation may be partially reused or not reused; the specific analysis is as follows: 1. The second treatment liquid is not subjected to solid-liquid separation; at this time, the second treatment liquid contains manganese-containing intermediate precipitates (manganese exists in the form of manganese hydroxide, and manganese exists mainly in the form of manganese hydroxide); during the oxidation process, when hypochlorite is subjected to deep manganese precipitation, it will also react with manganese hydroxide, which to a certain extent leads to an increase in the amount of hypochlorite added; however, not performing solid-liquid separation can save process flow and has certain advantages in simplicity.

[0047] 2. The second treatment liquid is subjected to solid-liquid separation, but the manganese-containing intermediate precipitate is not recycled; at this time, due to the solid-liquid separation, the second treatment liquid will not contain the manganese-containing intermediate precipitate; therefore, when hypochlorite is added subsequently, the amount of hypochlorite added will not be increased.

[0048] 3. The second treated liquid is subjected to solid-liquid separation, and after the third mixing, part of the manganese-containing intermediate precipitate is recycled; at this time, the recycled manganese-containing intermediate precipitate can reduce the residual chlorine content in the final water body; and, in the present invention, the manganese-containing intermediate precipitate is recycled only partially after the second mixing is completed, which will not interfere with the deep removal of manganese, will not increase the amount of hypochlorite added, and has little effect on the manganese precipitation in the oxidation process.

[0049] Based on the above supplementary explanation, as a preferred embodiment, the step S2 also includes: performing solid-liquid separation on the second treatment liquid to obtain a manganese-containing intermediate precipitate and the second treatment liquid after solid-liquid separation; that is, before executing the step S3, performing solid-liquid separation on the second treatment liquid to separate the manganese-containing intermediate precipitate.

[0050] Further, the step S3 further comprises: after completing the second mixing, adding part of the manganese-containing intermediate precipitate to the second treatment liquid after solid-liquid separation, and then performing a third mixing; the mass proportion of part of the manganese-containing intermediate precipitate in the intermediate precipitate is 10-30%, further 10-20% or 20-30%; the duration of the third mixing is not less than 5 minutes, further 5-15 minutes or 10-15 minutes. Alternatively, in the step S3, the manganese-containing intermediate precipitate is not added to the second treatment liquid.

[0051] In the above case, the molar ratio of the hypochlorite to the manganese ions in the second treatment solution is 1.1-1.8:1, further 1.3-1.8:1, further 1.4-1.7:1, further 1.5-1.6:1.

[0052] As another embodiment, solid-liquid separation is not performed in step S2 (in this case, the second treatment liquid is not subjected to solid-liquid separation, and the hypochlorite is directly added); the molar ratio of the hypochlorite to the manganese ions in the second treatment liquid is 2.3-3.2:1, further 2.5-3:1 or 2.8-3.2:1 or 2.3-2.7:1.

[0053] As a further explanation of the present invention: The present invention constructs a process system for treating manganese-containing wastewater such as manganese mine water based on the synergistic effect of "pH regulation-directional oxidation". By accurately controlling the pH value of the system in the manganese precipitation stage, the co-precipitation of calcium and magnesium ions is effectively suppressed while achieving efficient precipitation of manganese ions, breaking through the technical bottleneck of simultaneous precipitation of calcium and magnesium metal ions in traditional processes. For the trace manganese ions remaining after precipitation, hypochlorite oxidation is used to selectively convert dissolved manganese into manganese oxide precipitate. This process not only ensures the deep purification of manganese, but also realizes the resource utilization of manganese through the recyclability of the product, and finally simultaneously achieves the dual goals of resource utilization of manganese elements in wastewater and deep purification of water quality.

[0054] The present invention realizes ultra-efficient recovery and purification of manganese ions in wastewater by constructing a "precipitation-oxidation" two-stage synergistic system. In the precipitation stage, the pH is precisely controlled to allow manganese ions to preferentially form manganese hydroxide precipitates; in the oxidation stage, the residual manganese ions are directionally converted into manganese oxide products, breaking through the technical bottleneck of the difficulty in achieving both manganese recovery rate and purity in traditional processes. The present invention ultimately achieves a high recovery rate of manganese ions and a high purity of manganese precipitates, reducing costs by more than 40% compared to existing technologies, forming a full-chain closed-loop solution of "pollution control-resource regeneration-high-value utilization".

[0055] The present invention uses "precipitation-oxidation" to synergistically treat manganese mine water, and by constructing a process system that precisely controls pH and links hypochlorite oxidation reaction, it overcomes the industry problem of low efficiency of deep removal of manganese ions in traditional treatment processes. In the precipitation stage, the present invention forms a manganese-dominant precipitation zone by precisely controlling pH, and preferentially forms manganese-based precipitates (manganese hydroxide); in the oxidation enhancement stage, hypochlorite is used to deeply oxidize the residual manganese ions to stable MnO2 at room temperature, so that the manganese concentration of the effluent is stable <2mg / L, meeting the 2mg / L limit specified in the "Comprehensive Sewage Discharge Standard" (GB8978-1996).

[0056] The present invention develops a technical system of "manganese hydroxide internal circulation and coordinated chlorine control". By constructing a dynamic coupling mechanism between precipitation product and oxidation reaction, the industry problem of excessive residual chlorine and waste of reagents in the traditional hypochlorite oxidation process is overcome. The manganese hydroxide precipitate generated in the precipitation stage is innovatively quantitatively returned to the oxidation reaction unit to form a " "The self-purification reaction chain is formed to realize the in-situ reduction of residual chloride ions. The present invention uses the self-sustaining chlorine metabolism mechanism of the internal circulation system to achieve the goal of deep purification of effluent manganese concentration while simultaneously meeting the strict requirements of the "Pollutant Discharge Standard for Urban Sewage Treatment Plants" (GB18918-2002) on residual chlorine.

[0057] The present invention has constructed a breakthrough "precipitation-oxidation" process system. Through the innovative design of the reagent dosing optimization model and the coordinated control mechanism of the reaction path, it has successfully solved the technical dilemma of excessive consumption of chemical reagents in the traditional single treatment process. In view of the characteristics of high-manganese wastewater, the synergistic enhancement mechanism of alkaline regulator and hypochlorite is first created: in the pre-precipitation stage, pH control is used to achieve preferential precipitation of manganese ions and reduce manganese concentration; in the oxidation enhancement stage, manganese ions are converted into high-valent oxides to achieve deep purification of manganese.

[0058] The following are specific examples of the present invention: Example 1 At room temperature, sodium hydroxide was added to the manganese ore water (the molar ratio of sodium hydroxide to manganese ions in the manganese ore water was 3:1), and the pH was controlled to be 9.6 to obtain a first treatment liquid; 0.5% of the volume of the manganese ore water and 0.1% PAM (polyacrylamide) was added to the first treatment liquid, and the reaction was stirred for 60 minutes (at this time, the pH was 9.4, and the concentrations of manganese, calcium and magnesium were 9.5, 460.3 and 369.5 mg / L respectively after sampling and separation of the precipitate), and precipitate 1 (intermediate precipitate containing manganese) and the second treatment liquid were separated.

[0059] Table 1 Main ions and concentrations in manganese mine water in a mining area (mg / L) At room temperature, according to the molar ratio of sodium hypochlorite to residual manganese ions of 1.5:1, a sodium hypochlorite solution with a concentration of 10,000 mg / L was added to the second treatment solution. After stirring and reacting for 30 min, precipitate 2 (manganese-containing final precipitate) and manganese-removed water body (effluent) were separated; in the manganese-removed water body, the concentrations of manganese, calcium, and magnesium were 1.7, 458.0, and 365.3 mg / L respectively, the residual chlorine was 0.46 mg / L, and the pH was 8.7.

[0060] After drying the precipitate 1 (manganese-containing intermediate precipitate) of this example, the contents of manganese, calcium, and magnesium were 34.45%, 5.68%, and 3.91% respectively. As shown in Figure 1 shown, it mainly exists in the form of hydroxides.

[0061] After drying the precipitate 2 (manganese-containing final precipitate) of this example, the contents of manganese, calcium, and magnesium were 50.83%, 0.59%, and 0.28% respectively. As shown in Figure 2 shown, it mainly exists in the form of oxides.

[0062] Example 2 At room temperature, sodium hydroxide was added to the manganese ore water inrush (the same as in Example 1) to control the pH to 9.6 to obtain the first treatment solution; to the first treatment solution, PAM with a mass concentration of 0.1% and a volume of 0.5% of the manganese ore water inrush was added, and the mixture was stirred and reacted for 60 min (at this time, after sampling and separating the precipitate for detection, the concentrations of manganese, calcium, and magnesium were 9.5, 460.3, and 369.5 mg / L respectively), and precipitate 1 (manganese-containing intermediate precipitate) and the second treatment solution were separated.

[0063] At room temperature, according to the molar ratio of sodium hypochlorite to residual manganese ions of 1.6:1, a sodium hypochlorite solution with a concentration of 10,000 mg / L was added to the second treatment solution. After stirring and reacting for 30 min, 20% of precipitate 1 (manganese-containing intermediate precipitate) was refluxed, and then after continuing to react for 10 min, precipitate 2 (manganese-containing final precipitate) and manganese-removed water body (effluent) were separated; in the manganese-removed water body, the concentrations of manganese, calcium, and magnesium were 1.8, 454.7, and 368.1 mg / L respectively, the residual chlorine was 0.13 mg / L, and the pH was 8.8.

[0064] After drying the precipitate 2 (manganese-containing final precipitate) of this example, the contents of manganese, calcium, and magnesium were 45.83%, 1.02%, and 0.76% respectively.

[0065] Example 3 At room temperature, sodium hydroxide was added to the manganese ore effluent (the same as in Example 1), and the pH was controlled to 9.6 to obtain the first treatment solution; to the first treatment solution, PAM with a mass concentration of 0.1% and a volume of 0.5% of the manganese ore effluent was added, and the mixture was stirred and reacted for 60 min to obtain the second treatment solution; after sampling and separating the precipitate for detection, the concentrations of manganese, calcium, and magnesium were 9.5, 460.3, and 369.5 mg / L, respectively.

[0066] At room temperature, according to the molar ratio of sodium hypochlorite to residual manganese ions of 2.5:1, a sodium hypochlorite solution with a concentration of 10000 mg / L was added to the second treatment solution. After stirring and reacting for 30 min, the precipitate (manganese-containing final precipitate) and manganese-removed water body (effluent) were separated; in the manganese-removed water body, the concentrations of manganese, calcium, and magnesium were 0.51, 453.5, and 366.8 mg / L, respectively, the residual chlorine was 0.13 mg / L, and the pH was 8.5.

[0067] After drying the manganese-containing final precipitate of this example, the contents of manganese, calcium, and magnesium were 29.33%, 5.16%, and 3.57%, respectively. See Figure 3 As shown, it mainly exists in the form of hydroxides and oxides.

[0068] Example 4 At room temperature, sodium hydroxide (the molar ratio of sodium hydroxide to manganese ions in the manganese ore effluent was 2.6:1) was added to the manganese ore effluent (the same as in Example 1), and the pH was controlled to 9.3 to obtain the first treatment solution; to the first treatment solution, PAM with a mass concentration of 0.1% and a volume of 0.5% of the manganese ore effluent was added, and the mixture was stirred and reacted for 60 min to obtain the second treatment solution, and the pH of the second treatment solution was 9.1; after sampling and separating the precipitate for detection, the concentrations of manganese, calcium, and magnesium were 17.1, 475.3, and 370.5 mg / L, respectively.

[0069] At room temperature, according to the molar ratio of sodium hypochlorite to residual manganese ions of 2.5:1, a sodium hypochlorite solution with a concentration of 10000 mg / L was added to the second treatment solution. After stirring and reacting for 30 min, the precipitate (manganese-containing final precipitate) and manganese-removed water body (effluent) were separated; in the manganese-removed water body, the concentrations of manganese, calcium, and magnesium were 1.9, 472.8, and 367.3 mg / L, respectively, the residual chlorine was 0.21 mg / L, and the pH was 8.2.

[0070] After drying the manganese-containing final precipitate of this example, the contents of manganese, calcium, and magnesium were 36.18%, 4.86%, and 3.39%, respectively.

[0071] Example 5 At room temperature, sodium hydroxide (the molar ratio of sodium hydroxide to manganese ions in the manganese ore effluent is 2.8:1) was added to the manganese ore effluent (the same as in Example 1), and the pH was controlled at 9.5 to obtain the first treatment solution; to the first treatment solution, PAM with a mass concentration of 0.1% and a volume of 0.5% of the manganese ore effluent was added, and the mixture was stirred and reacted for 60 min to obtain the second treatment solution. The pH of the second separation solution was 9.3; after sampling and separating the precipitate for detection, the concentrations of manganese, calcium, and magnesium were 12.3, 466.5, and 365.2 mg / L, respectively.

[0072] At room temperature, according to the molar ratio of sodium hypochlorite to residual manganese ions of 3:1, a sodium hypochlorite solution with a concentration of 10,000 mg / L was added to the second treatment solution. After stirring and reacting for 30 min, the precipitate (manganese-containing final precipitate) and manganese-removed water body (effluent) were separated; in the manganese-removed water body, the concentrations of manganese, calcium, and magnesium were 0.40, 465.7, and 363.0 mg / L, respectively, the residual chlorine was 0.28 mg / L, and the pH was 8.3.

[0073] After drying the manganese-containing final precipitate of this example, the contents of manganese, calcium, and magnesium were 33.38%, 5.12%, and 3.65%, respectively.

[0074] Example 6 At room temperature, sodium hydroxide was added to the manganese ore effluent in another mining area (manganese concentration was 261.38 mg / L, calcium concentration was 491.75 mg / L, and magnesium concentration was 381.00 mg / L), and the pH was controlled at 9.5 to obtain the first treatment solution; to the first treatment solution, PAM with a mass concentration of 0.1% and a volume of 0.5% of the manganese ore effluent was added, and the mixture was stirred and reacted for 60 min to obtain the second treatment solution; after sampling and separating the precipitate for detection, the concentrations of manganese, calcium, and magnesium were 12.8, 444.8, and 336.0 mg / L, respectively.

[0075] At room temperature, according to the molar ratio of sodium hypochlorite to residual manganese ions of 2.5:1, a sodium hypochlorite solution with a concentration of 10,000 mg / L was added to the second treatment solution. After stirring and reacting for 30 min, the precipitate (manganese-containing final precipitate) and manganese-removed water body (effluent) were separated; in the manganese-removed water body, the concentrations of manganese, calcium, and magnesium were 1.36, 440.9, and 333.4 mg / L, respectively, the residual chlorine was 0.22 mg / L, and the pH was 8.3.

[0076] After drying the manganese-containing final precipitate of this example, the contents of manganese, calcium, and magnesium were 42.81%, 3.28%, and 2.40%, respectively.

[0077] Comparative Example 1 At room temperature, sodium hydroxide was added to the manganese ore effluent (same as in Example 1), and the pH was controlled to be 9.7 or 9.9 to obtain the first treatment solution; to the first treatment solution, PAM with a mass concentration of 0.1% and a volume of 0.5% of the manganese ore effluent was added, and the mixture was stirred and reacted for 60 min, and the final manganese-containing precipitate and the second treatment solution (effluent) were separated.

[0078] In this comparative example, when the pH of the first treatment solution reached 9.7, the molar ratio of sodium hydroxide to manganese ions in the manganese ore effluent was 5:1; when the pH of the first treatment solution reached 9.9, the molar ratio of sodium hydroxide to manganese ions in the manganese ore effluent was 8:1.

[0079] In this comparative example, only when a large amount of sodium hydroxide was added, the manganese ion concentration in the effluent could be lower than 2 mg / L, but at this time, a large amount of calcium and magnesium had precipitated, which would greatly reduce the purity of the recovered manganese hydroxide.

[0080] When the pH of the first treatment solution was 9.9, after drying the final manganese-containing precipitate in this comparative example, the contents of manganese, calcium, and magnesium were 15.57%, 2.04%, and 18.96% respectively.

[0081] Table 2 Experimental results at different pH values Comparative Example 2 At room temperature, in the manganese ore effluent (same as in Example 1), sodium hypochlorite solution with a concentration of 10000 mg / L was added according to the molar ratio of sodium hypochlorite to manganese ions of 1:1 or 1.2:1 or 1.4:1; after stirring and reacting for 1 h, the precipitate and the manganese-removed water body (effluent) were separated.

[0082] In this comparative example, when the molar ratio of sodium hypochlorite to manganese ions was 1:1, 1.2:1, and 1.4:1, the manganese concentrations in the manganese-removed water body were 19.80, 6.38, and 1.69 mg / L respectively.

[0083] In this comparative example, when the molar ratio of sodium hypochlorite to manganese ions was 1.4:1, the manganese ion content could meet the standard. However, a large amount of sodium hypochlorite was added, resulting in a significant increase in cost, and the residual chlorine content in the effluent was 8.22 mg / L, seriously exceeding the standard and unable to meet the discharge standard.

[0084] Comparative Example 3 At room temperature, sodium hydroxide was added to the manganese ore effluent (same as in Example 1), and the pH was controlled to be 9.5 to obtain the first treatment solution; to the first treatment solution, PAM with a mass concentration of 0.1% and a volume of 0.5% of the manganese ore effluent was added, and the mixture was stirred and reacted for 180 min to obtain the second treatment solution, and the pH of the second treatment solution was 8.7; after sampling and separating the precipitate for detection, the concentrations of manganese, calcium, and magnesium were 10.6, 461.1, and 354.8 mg / L respectively.

[0085] At room temperature, according to the molar ratio of sodium hypochlorite to residual manganese ions of 3:1, a sodium hypochlorite solution with a concentration of 10,000 mg / L was added to the second treatment liquid. After stirring and reacting for 30 minutes, the precipitate (final manganese-containing precipitate) and manganese-removed water body (effluent) were separated. In the manganese-removed water body, the concentrations of manganese, calcium, and magnesium were 5.3, 458.6, and 353.5 mg / L respectively, the residual chlorine was 1.84 mg / L, the pH was 7.6, and both manganese and residual chlorine exceeded the standards.

[0086] In this comparative example, when the pH of the second treatment liquid was too low, the oxidation effect of adding sodium hypochlorite on manganese was significantly reduced, the deep purification of manganese could not be achieved, and the residual chlorine content was relatively high.

[0087] In the above technical solutions of the present invention, the above are only the preferred embodiments of the present invention, and do not limit the patent scope of the present invention accordingly. Any equivalent structural transformation made by using the content of the specification and drawings of the present invention under the technical concept of the present invention, or direct / indirect application in other related technical fields, is included in the patent protection scope of the present invention.

Claims

1. A resource treatment method for manganese-containing wastewater, characterized in that, Including the steps: S1. Add an alkaline regulator to the manganese-containing wastewater to obtain a first treatment liquid with a pH of 9.3 - 9.

65. The manganese-containing wastewater contains manganese ions, calcium ions, and magnesium ions; in the manganese-containing wastewater, the concentration of the manganese ions is 80 - 500 mg / L; the mass of the manganese ions is less than the mass of the calcium and magnesium ions, and the mass of the calcium and magnesium ions is the sum of the masses of the calcium ions and the magnesium ions. S2. Add a flocculant to the first treatment liquid and then conduct a first mixing to obtain a second treatment liquid with a pH of 9.0 - 9.

5. S3. Add a hypochlorite to the second treatment liquid and then conduct a second mixing, followed by solid-liquid separation to obtain a manganese-containing final precipitate and a manganese-removed water body.

2. The resource treatment method for manganese-containing wastewater according to claim 1, wherein The alkaline regulator includes one or more of sodium hydroxide, potassium hydroxide, and calcium oxide.

3. The resource treatment method for manganese-containing wastewater according to claim 1, characterized in that The flocculant includes one or more of polyacrylamide, polyaluminum chloride, and polyferric sulfate; the mass percentage of the flocculant and the manganese-containing wastewater is 0.1 - 1‰.

4. The resource treatment method for manganese-containing wastewater according to claim 1, characterized in that, The hypochlorite includes one or more of sodium hypochlorite, potassium hypochlorite, and calcium hypochlorite; the molar ratio of the hypochlorite to the manganese ions in the second treatment liquid is 1.1 - 3.2:

1.

5. The resource treatment method for manganese-containing wastewater according to claim 1, characterized in that, The duration of the first mixing is 40 - 80 min.

6. The resource treatment method for manganese-containing wastewater according to claim 1, wherein The duration of the second mixing is not less than 20 min.

7. The resource treatment method for manganese-containing wastewater according to claim 1, characterized in that, Step S2 further includes: conducting solid-liquid separation on the second treatment liquid to obtain a manganese-containing intermediate precipitate and the second treatment liquid after solid-liquid separation.

8. The resource treatment method for manganese-containing wastewater according to claim 7, characterized in that, Step S3 further includes: after completing the second mixing, adding a part of the manganese-containing intermediate precipitate, and then conducting a third mixing; the mass proportion of the part of the manganese-containing intermediate precipitate in the manganese-containing intermediate precipitate is 10 - 30%; the duration of the third mixing is not less than 5 min.

9. The resource treatment method for manganese-containing wastewater according to claim 7 or 8, characterized in that, The molar ratio of the hypochlorite to the manganese ions in the second treatment liquid is 1.1 - 1.8:

1.

10. The resource treatment method for manganese-containing wastewater according to claim 1, characterized in that, In step S2, no solid-liquid separation is conducted; the molar ratio of the hypochlorite to the manganese ions in the second treatment liquid is 2.3 - 3.2:1.

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