Manganese-containing metallurgical wastewater treatment method based on iron mineral-based material catalytic oxidation self-precipitation technology

Abstract

The invention discloses a manganese-containing ore metallurgical wastewater treatment method based on an iron mineral-based material catalytic oxidation self-precipitation technology, and the treatment method comprises the following steps: pre-adjusting the pH value of the manganese-containing ore metallurgical wastewater, and removing non-complexed divalent manganese ions and coexisting pollutants; an iron mineral-based catalyst is added, ozone is introduced to form strong oxidizing free radicals, the iron mineral-based catalyst is subjected to mineral phase reconstruction and homogeneous dissolution, and iron atoms are converted and released into high-valence iron; the ozone, the strong-oxidizing free radicals and the high-valence iron cooperate to catalyze and oxidize complex-state and non-complex-state divalent manganese ions, and the manganese ions are subjected to form transformation to generate self-precipitation; high-valence iron is bridged to form a net, iron self-flocculation occurs, and ferromanganese ions are subjected to a flocculation-co-precipitation reaction to obtain a flocculation-co-precipitate; and separating through an inclined tube sedimentation tank. By introducing the iron mineral-based catalyst, efficient conversion of ozone and oxidation and deep removal of complexing state and non-complexing state manganese ions are realized, the cost is reduced, and the purpose of treating waste with waste is realized.

Description

Technical Field

[0001] This invention relates to the field of industrial wastewater treatment methods, and more particularly to a method for treating manganese-containing mining and metallurgical wastewater based on catalytic oxidation self-precipitation technology using iron mineral-based materials. Background Technology

[0002] Wastewater discharged from the mining and metallurgical industries (such as manganese mining, hydrometallurgy, electrolytic manganese production, and battery material processing) often contains high concentrations of Mn. 2+ Its concentration ranges from 50 to 2000 mg / L, far exceeding the limit of 0.1 mg / L in the "Emission Standard of Pollutants for Copper, Nickel and Cobalt Industry" (GB25467-2010) and the emission requirements of the "Integrated Wastewater Discharge Standard" (GB 8978-1996).

[0003] Traditional methods for removing manganese ions include chemical precipitation, adsorption, biological methods, and advanced oxidation processes (AOPs). However, all traditional methods have significant drawbacks, such as: (1) Chemical precipitation method: This requires adding an excess of oxidant (such as potassium permanganate or chlorine) or alkali (such as NaOH) to precipitate Mn. 2+ Oxidation to MnO2 precipitate is costly (accounting for more than 60% of the treatment cost) and easily introduces heavy metal impurities; (2) Adsorption method: Relying on adsorbents such as activated carbon and molecular sieves, for high concentrations of Mn 2+ (>500 mg / L) Insufficient adsorption capacity (<50 mg / g), high regeneration frequency leads to increased operating costs; (3) Biological method: limited by the sensitivity of microorganisms to pH (requires 6.5-8.5) and temperature (20-30℃), and also by the coexistence of Fe 2+ It has poor tolerance to inhibitory substances such as COD and is difficult to consistently meet the standards; (4) Advanced oxidation methods (AOPs): such as the Fenton process and photocatalytic oxidation, although highly efficient, require the addition of H2O2, ultraviolet light sources, etc., resulting in significant energy consumption and reagent costs; ozone oxidation of Mn alone 2+ At that time, because Mn 2+ High reduction potential (E) 0 =1.23 V), direct oxidation efficiency <30%, requiring catalyst enhancement.

[0004] Existing ozone catalytic oxidation catalysts are mostly made of precious metals (Pt, Pd) or artificially synthesized materials, which suffer from problems such as complex preparation, high cost, and easy deactivation. In contrast, low-grade iron minerals (such as magnetite, hematite, goethite, and limonite) are abundant and inexpensive, and contain Fe... 2+ / Fe 3+The active sites can catalyze the decomposition of ozone into strong oxidizing species such as hydroxyl radicals (·OH), and can also participate in the oxidation-flocculation process. However, existing studies have mostly focused on the degradation of organic matter, and lack a systematic analysis of the synergistic mechanism of "catalytic oxidation-mineral phase reconstruction-self precipitation" for the deep removal of manganese ions. Furthermore, the relationship between process parameters and resource recovery has not been clarified.

[0005] Therefore, there is an urgent need to develop a method for removing manganese ions from mining and metallurgical wastewater that uses iron mineral-based materials as catalysts and combines ozone oxidation with self-precipitation. Summary of the Invention

[0006] In view of the above-mentioned shortcomings of current methods for removing manganese ions from mining and metallurgical wastewater, this invention provides a method for treating manganese-containing mining and metallurgical wastewater based on catalytic oxidation and self-precipitation technology using iron mineral-based materials. By introducing an iron mineral-based catalyst, the method achieves efficient conversion of ozone and oxidation and deep removal of complexed and non-complexed manganese ions, reducing costs while realizing waste treatment from waste.

[0007] To achieve the above objectives, embodiments of the present invention employ the following method: A method for treating manganese-containing mining and metallurgical wastewater based on catalytic oxidation and self-precipitation technology using iron mineral-based materials, wherein the manganese-containing mining and metallurgical wastewater includes manganese ions, and the steps of the method include: The pH of manganese-containing mining and metallurgical wastewater is pre-adjusted to 6-9 to remove non-complexed divalent manganese ions and coexisting pollutants under weakly alkaline conditions. An iron mineral-based catalyst is added to pre-treated manganese-containing mining wastewater and ozone is introduced. The ozone forms a strong oxidizing free radical under the action of the iron mineral-based catalyst. At the same time, the mineral phase of the iron mineral-based catalyst undergoes homogeneous dissolution due to reconstruction, and iron atoms are converted and released into high-valent iron. The ozone, the strong oxidizing free radical, and the high-valent iron synergistically catalyze the oxidation of complexed and non-complexed divalent manganese ions, causing the manganese ion form to transform and undergo self-precipitation. The high-priced iron bridges are connected into a network, and iron self-flocculation occurs. Manganese and iron ions undergo flocculation-coprecipitation reaction to obtain flocculated-coprecipitates. The flocculated-coprecipitate is separated in an inclined tube sedimentation tank.

[0008] According to one aspect of the present invention, the water quality conditions of the manganese-containing mining and metallurgical wastewater are: Mn 2+ Concentrations range from 50 to 2000 mg / L, pH ranges from 2.0 to 7.0, water temperatures range from 10 to 35℃, and coexisting pollutants include Al. 3+ Fe 2+ SS and COD.

[0009] According to one aspect of the invention, the pre-adjusted pH to 6-9 non-complexed divalent manganese ions react with OH- under weakly alkaline conditions.- Mn(OH)2 flocs are generated, and at the same time, Fe in the wastewater is reacted. 2+ Al 3+ and Ca 2+ Coexisting metal ions undergo co-precipitation removal reactions, reducing the downstream oxidation load.

[0010] According to one aspect of the present invention, the iron mineral-based catalyst is a low-grade porous iron mineral-based catalyst, which is obtained by crushing and ball milling to a particle size of 50-200 mesh, followed by calcination at 300-500°C for 1-2 hours, and the specific surface area of ​​the low-grade porous iron mineral-based catalyst is 10-50 m². 2 / g, total iron content ≥40%, of which active Fe 2+ It accounts for 10%-30%.

[0011] According to one aspect of the present invention, the formation of strongly oxidizing free radicals by ozone under the action of an iron mineral-based catalyst is the formation of Fe radicals by ozone on the iron mineral-based catalyst. 2+ / Fe 3+ Under the influence of the active site, a chain decomposition occurs, which is directionally transformed into hydroxyl radicals, superoxide radicals and singlet oxygen.

[0012] According to one aspect of the present invention, the homogeneous dissolution of the iron mineral-based catalyst phase reconstruction refers to the heterogeneous dissolution of the original crystalline phase of the catalyst under the continuous action of ozone / free radicals. During the reconstruction process, Fe on the catalyst surface dissolves in ionic or colloidal state and dissociates into amorphous Fe(OH)3 and γ-FeOOH.

[0013] According to one aspect of the invention, the iron atoms that are converted and released into high-valence iron refer to Fe. 3+ The high-valence iron includes: free Fe 3+ Fe(OH)3 colloid and amorphous iron oxides, wherein the amorphous iron oxides include γ-FeOOH and FeOOH·nH2O, and the Fe in the iron mineral-based catalyst 2+ Under the action of ozone / free radicals, it is preferentially released and oxidized to Fe. 3+ .

[0014] According to one aspect of the present invention, the manganese ion speciation conversion refers to Mn2 + Under the synergistic effect of ozone and free radicals, it is oxidized to MnO2 and permanganate (MnO4). - The MnO2 exists in the form of amorphous nanoparticles with a particle size of 10-50 nm and undergoes initial self-precipitation.

[0015] According to one aspect of the present invention, the high-priced iron bridging network is formed by hydroxyl bridging to form "-Fe-O-Fe-", and the "-Fe-O-Fe-" network traps MnO2 particles, heavy metal ions and residual suspended matter generated by oxidation to form a three-dimensional network aggregate flocculent, in which iron self-flocculation occurs and manganese iron ions undergo flocculation-coprecipitation reaction.

[0016] According to one aspect of the present invention, the method for treating manganese-containing mining and metallurgical wastewater based on catalytic oxidation self-precipitation technology using iron mineral-based materials is carried out in an integrated baffled reactor.

[0017] Advantages of this invention: The above method achieves the following effects: (1) High removal efficiency: Fe in low-grade porous iron mineral-based catalysts 2+ / Fe 3+ The active sites can catalyze the decomposition of ozone into strong oxidizing species such as hydroxyl radicals, significantly improving oxidation efficiency; through O3 / radical / Fe 3+ Synergistic oxidation and iron flocculation self-precipitation, Mn 2+ The removal rate is over 99.95% (effluent ≤ 0.1 mg / L when influent is 800 mg / L), and the total iron removal rate is > 99%; the catalyst undergoes mineral phase reconstruction during the reaction process, and the released iron ions achieve co-precipitation removal of manganese and iron ions through self-flocculation. (2) Low cost: Low-grade iron minerals with a cost of less than 200 yuan / ton, such as tailings and waste rock, are used as catalysts to replace precious metal catalysts, reducing the treatment cost by more than 60%. (3) Achieve resource recycling: The flocculation-coprecipitate contains MnO2 (15%-30% manganese) and Fe(OH)3 (20%-35% iron). After dehydration, it can be used to fill mines or make compound fertilizer, thus achieving waste treatment and resource recycling. (4) Environmentally friendly: Only ozone needs to be added, no additional oxidant is required, and the water content of the flocculated-coprecipitate is ≤70%, reducing secondary pollution; (5) Strong stability: After the catalyst mineral phase is reconstructed, the active sites are regenerated, the proportion of amorphous iron is >50%, and the activity decreases by <10% after 30 days of continuous operation. Attached Figure Description

[0018] To more clearly illustrate the method solutions in the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1This is a schematic diagram of the process flow for a manganese-containing mining and metallurgical wastewater treatment method based on catalytic oxidation and self-precipitation technology using iron mineral-based materials, as described in this invention. Figure 2 This is a schematic diagram illustrating the mechanism of the iron mineral-based catalyst catalytic ozone decomposition of free radicals in a manganese-containing mining and metallurgical wastewater treatment method based on iron mineral-based material catalytic oxidation self-precipitation technology, as described in this invention. Figure 3 This is a schematic diagram of the iron dissolution and flocculation mechanism during the mineral phase reconstruction process of a manganese-containing mining and metallurgical wastewater treatment method based on catalytic oxidation self-precipitation technology of iron mineral-based materials, as described in this invention. Figure 4 In an embodiment of the manganese-containing mining and metallurgical wastewater treatment method based on catalytic oxidation and self-precipitation technology of iron mineral-based materials according to the present invention, Mn 2+ Concentration versus time curve; Figure 5 In an embodiment of the manganese-containing mining and metallurgical wastewater treatment method based on catalytic oxidation and self-precipitation technology of iron mineral-based materials according to the present invention, Mn 4+ Concentration versus time curve. Detailed Implementation

[0020] The method solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0021] like Figure 1-3 As shown, a method for treating manganese-containing mining and metallurgical wastewater based on catalytic oxidation and self-precipitation technology using iron mineral-based materials includes the following steps: The pH of manganese-containing mining and metallurgical wastewater is pre-adjusted to 6-9 to remove non-complexed divalent manganese ions and coexisting pollutants under weakly alkaline conditions. An iron mineral-based catalyst is added to pre-treated manganese-containing mining wastewater and ozone is introduced. The ozone forms a strong oxidizing free radical under the action of the iron mineral-based catalyst. At the same time, the mineral phase of the iron mineral-based catalyst undergoes homogeneous dissolution due to reconstruction, and iron atoms are converted and released into high-valent iron. The ozone, the strong oxidizing free radical, and the high-valent iron synergistically catalyze the oxidation of complexed and non-complexed divalent manganese ions, causing the manganese ion form to transform and undergo self-precipitation. The high-priced iron bridges are connected into a network, and iron self-flocculation occurs. Manganese and iron ions undergo flocculation-coprecipitation reaction to obtain flocculated-coprecipitates. The flocculated-coprecipitate is separated in an inclined tube sedimentation tank.

[0022] In practical applications, the influent water quality conditions for manganese-containing mining and metallurgical wastewater are: Mn 2+ Concentrations range from 50 to 2000 mg / L, pH ranges from 2.0 to 7.0, water temperatures range from 10 to 35℃, and coexisting pollutants include Al. 3+ (≤100 mg / L), Fe 2+ (≤100 mg / L) and other metal ions (≤50 mg / L), SS (≤300 mg / L) and COD ≤400 mg / L.

[0023] In practical applications, the steps for pre-adjusting the pH of manganese-containing mining and metallurgical wastewater are as follows: add acid or alkali to the manganese-containing mining and metallurgical wastewater to adjust the pH to 6-9. When the original water pH is <6, add sodium hydroxide, calcium hydroxide, or sodium carbonate; when the original water pH is >9, add sulfuric acid, hydrochloric acid, or nitric acid.

[0024] In practical applications, the pH of the original manganese-containing mining and metallurgical wastewater is pre-adjusted to achieve a Mn content of 50%-60%. 2+ Under weakly alkaline conditions, it reacts with OH-. - Mn(OH)2 flocs are generated, and at the same time, Fe in the wastewater is reacted. 2+ Al 3+ Ca 2+ Co-precipitation of coexisting metal ions reduces the oxidation load at the downstream stage.

[0025] In practical applications, the composition of low-grade porous iron mineral-based catalysts is magnetite (Fe3O4, containing Fe). 2+ / Fe 3+ Hematite (α-Fe₂O₃, containing Fe) 3+ Goethite (α-FeOOH, containing Fe) 3+ ) or goethite (containing Fe2O3·nH2O, Fe 2+ / Fe 3+ One or more of the following (mixtures).

[0026] In practical applications, the iron mineral-based catalyst is a low-grade porous iron mineral-based catalyst, which is obtained by crushing and ball milling to a particle size of 50-200 mesh, followed by calcination at 300-500℃ for 1-2 hours. The specific surface area of ​​the low-grade porous iron mineral-based catalyst is 10-50 m². 2 / g, total iron content ≥40%, of which active Fe 2+ It accounts for 10%-30%.

[0027] In practical applications, ozone is introduced into manganese-containing mining wastewater with pre-adjusted pH. Ozone molecules undergo directional and efficient conversion under the action of iron mineral-based catalysts, forming strong oxidizing free radicals, which significantly improves ozone utilization efficiency and extends the half-life oxidation time.

[0028] In practical applications, the conversion of ozone into strong oxidizing free radicals is the process of ozone (O3) reacting with iron-based mineral catalysts in the Fe... 2+ / Fe 3+ Under the influence of the active site, a chain reaction occurs, resulting in the directional conversion of hydroxyl radicals (·OH, E). 0 =2.80V), superoxide radicals (·O2) - E 0 =-0.33V), singlet oxygen ( 1 O2, E 0 =2.42V).

[0029] In practical applications, the strong oxidizing free radicals converted from ozone are mainly hydroxyl radicals (·OH), which contribute to prolonging the half-life, increasing the oxidation potential, and achieving the desired effect on Mn. 2+ It is effective in highly efficient oxidation.

[0030] In practical applications, ozone is introduced as follows: an ozone generator produces O3 gas with a concentration of 30-100 mg / L, which is continuously introduced into the reaction system through a titanium alloy microporous aeration head at a flow rate of 0.5-2 L / (min·L wastewater) for 20-60 minutes, so that the dissolved oxygen concentration in the reaction system is maintained at 5-8 mg / L, and the ozone utilization rate is ≥85%.

[0031] In practical applications, the conversion and release of iron into ferric iron (Fe3+) results in ferric ions, including free Fe2+. 3+ Fe(OH)3 colloids and amorphous iron oxides, such as γ-FeOOH and FeOOH·nH2O.

[0032] In practical applications, Fe in catalysts 2+ Under the action of ozone / free radicals, it is preferentially released and oxidized to Fe. 3+ The amount released accounts for 20%-40% of the total iron content of the catalyst.

[0033] In practical applications, the conditions for synergistic catalytic oxidation reaction are: reaction temperature 25-40℃, stirring rate 100-180 r / min, and reaction time 30-60 minutes.

[0034] In practical applications, the transformation of manganese ion speciation refers to the transformation of Mn ions. 2+ Under the synergistic effect of ozone and free radicals, it is oxidized to tetravalent manganese oxide, namely MnO2, accounting for ≥85%, with a small amount of permanganate, namely MnO4. - The proportion is ≤15%, of which MnO2 exists in the form of amorphous nanoparticles with a particle size of 10-50nm and is initially precipitated.

[0035] In practical applications, homogeneous reconstruction of iron mineral-based catalysts refers to the heterogeneous dissolution of the original crystalline phase of the catalyst, such as Fe3O4 and α-Fe2O3, under the continuous action of ozone / free radicals. During the reconstruction process, Fe on the catalyst surface dissolves in ionic or colloidal form and dissociates into amorphous Fe(OH)3 and γ-FeOOH. After reconstruction, the proportion of amorphous iron increases to more than 50%.

[0036] In practical applications, the high-priced iron bridging network refers to the following: multi-form Fe leached from the homogeneous dissolution of the mineral phase is bridged by hydroxyl groups to form "-Fe-O-Fe-". The "-Fe-O-Fe-" network traps MnO2 particles, heavy metal ions and residual suspended matter generated by oxidation, forming a three-dimensional network aggregate floc. After trapping the MnO2 particles, heavy metal ions and residual suspended matter generated by oxidation, the average particle size of the floc increases to 0.5-2 mm, and the settling velocity is ≥1.5 cm / min.

[0037] In practical applications, the treatment method for manganese-containing mining and metallurgical wastewater based on the catalytic oxidation self-precipitation technology of iron mineral-based materials is completed in an integrated baffled reactor.

[0038] In practical applications, the integrated baffled reactor is divided into a premixing zone, a catalytic oxidation zone, and a flocculation and sedimentation zone.

[0039] In practical applications, the premixing zone of the integrated baffle reactor is used for pH adjustment, with a hydraulic retention time of 10-20 minutes.

[0040] In practical applications, ozone is introduced into the catalytic oxidation zone of the integrated baffle reactor, with a catalyst dosage of 0.5-1 g / L.

[0041] In practical applications, the hydraulic retention time for mineral phase reconstruction and self-precipitation reactions in integrated baffled reactors is 40-80 minutes.

[0042] In practical applications, the volume ratio of the premixing zone, catalytic oxidation zone, and flocculation sedimentation zone in an integrated baffled reactor is 1:3:2.

[0043] In practical applications, the final effluent from the manganese-containing mining and metallurgical wastewater treatment method, which utilizes catalytic oxidation and self-precipitation technology based on iron mineral-based materials, after reaction in an integrated baffled reactor, contains Mn. 2+ Concentration ≤ 0.1 mg / L, total iron concentration ≤ 0.3 mg / L.

[0044] In practical applications, the flocculated-coprecipitate after reaction in an integrated baffled reactor using a manganese-containing mining and metallurgical wastewater treatment method based on iron mineral-based catalytic oxidation self-precipitation technology passes through a surface loading of 1.0-1.5 m. 3 / (m 2The flocculated-coprecipitate is separated in an inclined tube sedimentation tank (h). The main components of the flocculated-coprecipitate are MnO2, with a manganese content of 15%-30%, Fe(OH)3, and an iron content of 20%-35%, with a water content of ≤70%.

[0045] Example 1 Using Mn 2+ The concentration was 800 mg / L, the initial pH was 3.5, the water temperature was 25℃, and the coexisting Fe... 2+ 50 mg / L, Al 3+ Wastewater with a concentration of 20 mg / L, SS of 150 mg / L, and COD of 200 mg / L was treated.

[0046] The pH was pre-adjusted to 7.5 by adding calcium hydroxide with a purity ≥90%, and then hydraulically retained for 15 minutes in a premixed zone (1 / 6 volume). Reaction results showed that 35% Mn... 2+ Mn(OH)2 flocculent precipitate is formed, and the supernatant contains Mn 2+ Reduced to 520 mg / L; Fe 2+ Removal rate 40%, remaining 30 mg / L; Al 3+ Removal rate 50%, remaining 10 mg / L.

[0047] Add limonite-based catalyst, crush and ball-mill to 100 mesh, calcine at 400℃ for 1.5 hours; Characterization: specific surface area 32 m² 2 / g, total iron 48%, active Fe 2+ The proportion is 22%, the dosage is 0.8 g / L; O3 gas is introduced: concentration 60 mg / L, titanium alloy microporous aerator head, flow rate 1 L / (min·L wastewater), aeration time 40 minutes, DO maintained at 6 mg / L.

[0048] The catalytic oxidation reaction was carried out in a catalytic oxidation zone comprising 3 / 6 of the total volume, at a reaction temperature of 30℃, a stirring rate of 150 r / min, and a reaction time of 45 minutes. The reaction results were observed using TEM. 2+ Oxidation to MnO2, comprising 90% amorphous nanoparticles with a particle size of 30nm, with an initial sedimentation efficiency of 45%, resulted in effluent Mn... 2+ It is 286 mg / L.

[0049] After ore phase reconstruction, XRD analysis showed that amorphous iron accounted for 58%, and Fe... 3+ The dissolution rate was 0.12 mg / (g catalyst·min). MnO2 was captured by a three-dimensional flocculent network, and the final effluent contained Mn. 2+ The concentration of total iron was 0.08 mg / L, and the concentration of total iron was 0.25 mg / L. The reaction was carried out in a flocculation and sedimentation zone accounting for 2 / 6 of the volume, with a hydraulic retention time of 60 minutes.

[0050] Flocculation-coprecipitate was subjected to a surface loading of 1.2 m. 3 / (m 2 The mixture was separated in an inclined tube sedimentation tank (h), with a water content of 65%. The composition analysis showed that it contained MnO2 (25% manganese) and Fe(OH)3 (30% iron), with a Mn / Fe molar ratio of 1:2.5. The mixture was then returned to the mine for backfilling.

[0051] Example 2 Using Mn 2+ The concentration was 1500 mg / L, the initial pH was 5.0, the water temperature was 30℃, and the coexisting Ca... 2+ Wastewater with a concentration of 40 mg / L, SS of 200 mg / L, and COD of 350 mg / L was treated.

[0052] Sodium hydroxide was added to pre-adjust the pH to 8.0, and the mixture was hydraulically retained for 20 minutes in a premixed zone with a volume ratio of 1 / 6. Reaction results showed that 40% Mn... 2+ Mn(OH)2 flocculent precipitate is formed, and the supernatant contains Mn 2+ Reduced to 900 mg / L; Ca 2+ Removal rate 30%, remaining 28 mg / L.

[0053] Add magnetite-hematite composite catalyst (magnetite:hematite = 1:1), crush and ball-mill to 150 mesh, calcine at 450℃ for 1 hour; Characterization: specific surface area 40 m² 2 / g, total iron 52%, active Fe 2+ The proportion is 25%, the dosage is 1.0 g / L; O3 gas is introduced: concentration 80 mg / L, flow rate 1.5 L / (min·L wastewater), aeration time 50 minutes, DO is maintained at 7 mg / L, and ozone utilization rate is 90%.

[0054] The catalytic oxidation reaction was carried out in a catalytic oxidation zone comprising 3 / 6 of the total volume, at a reaction temperature of 35℃, a stirring rate of 180 r / min, and a reaction time of 50 min. The reaction results were observed using TEM. 2+ Oxidation to MnO2, comprising 88% amorphous nanoparticles with a particle size of 40 nm, resulted in an initial precipitation efficiency of 48%, with effluent containing Mn. 2+ It is 468 mg / L.

[0055] After ore phase reconstruction, XRD analysis showed that amorphous iron accounted for 60%, and Fe... 3+ The dissolution rate was 0.18 mg / (g catalyst·min). The reaction was carried out in a flocculation sedimentation zone comprising 2 / 6 of the total volume, with a hydraulic retention time of 30 minutes. MnO2 was captured by a three-dimensional flocculent network, and the final effluent contained Mn. 2+The concentration was 0.09 mg / L, and the total iron concentration was 0.28 mg / L.

[0056] Flocculation-coprecipitate was subjected to a surface loading of 1.2. m3 / (m 2 The flocculated-coprecipitate was separated in an inclined tube sedimentation tank (h). The water content of the flocculated-coprecipitate was 68%. The composition analysis showed that it contained MnO2 (manganese content 28%) and Fe(OH)3 (iron content 32%), with a Mn / Fe molar ratio of 1:2.8. It can be used as a raw material for iron-manganese compound fertilizer and can be compounded with phosphate rock powder (NPK=5-10-5).

[0057] Example 3 Using Mn 2+ At a concentration of 50 mg / L, an initial pH of 6.5, and a water temperature of 15℃, coexisting Fe... 2+ Wastewater with a concentration of 10 mg / L and an SS concentration of 50 mg / L was treated.

[0058] No pH pre-adjustment is required, or a small amount of sodium carbonate can be added to adjust the pH to 6.8. The mixture should be hydraulically retained for 30 minutes in a premixing zone that accounts for 1 / 6 of the volume.

[0059] Add goethite-based catalyst, magnetite:hematite = 1:1, goethite, 100 mesh, roasted at 300℃ for 2 hours; total iron 42%, active Fe 2+ The proportion is 10%, the dosage is 0.5 g / L; O3 gas is introduced: concentration 30 mg / L, flow rate 0.5 L / (min·L wastewater), aeration time 20 minutes, DO is maintained at 5 mg / L.

[0060] The catalytic oxidation reaction was carried out in a catalytic oxidation zone that accounted for 3 / 6 of the volume, at a reaction temperature of 25°C, a stirring rate of 100 r / min, and a reaction time of 30 minutes.

[0061] Mn was finally extracted from the water 2+ The concentration of total iron was 0.2 mg / L, and the water content of the flocculated-coprecipitate was 70%, achieving the discharge standard.

[0062] The above examples demonstrate that the method of the present invention exhibits high efficiency in removing manganese ions from mining and metallurgical wastewater with different concentrations (50-2000 mg / L) and different initial pH values ​​(2.0-7.0). Furthermore, by utilizing a low-grade iron mineral catalyst and a self-precipitation mechanism, it achieves low-cost, resource-efficient deep removal of manganese ions.

[0063] Advantages of this invention: The above method achieves the following effects: (1) High removal efficiency: Fe in low-grade porous iron mineral-based catalysts 2+ / Fe 3+The active sites can catalyze the decomposition of ozone into strong oxidizing species such as hydroxyl radicals, significantly improving oxidation efficiency; through O3 / radical / Fe 3+ Synergistic oxidation and iron flocculation self-precipitation, Mn 2+ The removal rate is over 99.95% (effluent ≤ 0.1 mg / L when influent is 800 mg / L), and the total iron removal rate is > 99%; the catalyst undergoes mineral phase reconstruction during the reaction process, and the released iron ions achieve co-precipitation removal of manganese and iron ions through self-flocculation. (2) Low cost: Low-grade iron minerals with a cost of less than 200 yuan / ton, such as tailings and waste rock, are used as catalysts to replace precious metal catalysts, reducing the treatment cost by more than 60%. (3) Realize resource recycling: The flocculation-coprecipitate contains MnO2 (15%-30% manganese) and Fe(OH)3 (20%-35% iron). After dehydration, it can be used to fill mines or make compound fertilizer, realizing waste treatment and resource recycling. (4) Environmentally friendly: Only ozone needs to be added, no additional oxidant is required, and the water content of the flocculated-coprecipitate is ≤70%, reducing secondary pollution; (5) Strong stability: After the catalyst mineral phase is reconstructed, the active sites are regenerated, the proportion of amorphous iron is >50%, and the activity decreases by <10% after 30 days of continuous operation.

[0064] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the methods disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for treating manganese-containing mining and metallurgical wastewater based on catalytic oxidation and self-precipitation technology using iron mineral-based materials, wherein the manganese-containing mining and metallurgical wastewater comprises manganese ions, characterized in that, The steps of the manganese-containing mining and metallurgical wastewater treatment method based on iron mineral-based material catalytic oxidation self-precipitation technology include: The pH of manganese-containing mining and metallurgical wastewater is pre-adjusted to 6-9 to remove non-complexed divalent manganese ions and coexisting pollutants under weakly alkaline conditions. An iron mineral-based catalyst is added to pre-treated manganese-containing mining wastewater and ozone is introduced. The ozone forms a strong oxidizing free radical under the action of the iron mineral-based catalyst. At the same time, the mineral phase of the iron mineral-based catalyst undergoes homogeneous dissolution due to reconstruction, and iron atoms are converted and released into high-valent iron. The ozone, the strong oxidizing free radical, and the high-valent iron synergistically catalyze the oxidation of complexed and non-complexed divalent manganese ions, causing the manganese ion form to transform and undergo self-precipitation. The high-priced iron bridges are connected into a network, and iron self-flocculation occurs. Manganese and iron ions undergo flocculation-coprecipitation reaction to obtain flocculated-coprecipitates. The flocculated-coprecipitate is separated in an inclined tube sedimentation tank.

2. The method for treating manganese-containing mining and metallurgical wastewater based on catalytic oxidation and self-precipitation technology using iron mineral-based materials according to claim 1, characterized in that, The water quality conditions of the manganese-containing mining wastewater are: Mn 2+ Concentrations ranged from 50 to 2000 mg / L, pH from 2.0 to 7.0, water temperatures from 10 to 35℃, and coexisting pollutants included Al. 3+ Fe 2+ SS and COD.

3. The method for treating manganese-containing mining and metallurgical wastewater based on catalytic oxidation and self-precipitation technology using iron mineral-based materials according to claim 1, characterized in that, The pre-adjusted pH to 6-9 non-complexed divalent manganese ions react with OH- under weakly alkaline conditions. - Mn(OH)2 flocs are generated, and at the same time, Fe in the wastewater is reacted. 2+ Al 3+ and Ca 2+ Coexisting metal ions undergo co-precipitation removal reactions, reducing the downstream oxidation load.

4. The method for treating manganese-containing mining and metallurgical wastewater based on catalytic oxidation and self-precipitation technology using iron mineral-based materials according to claim 1, characterized in that, The iron mineral-based catalyst is a low-grade porous iron mineral-based catalyst, which is obtained by crushing and ball milling to a particle size of 50-200 mesh, followed by calcination at 300-500℃ for 1-2 hours. The specific surface area of ​​the low-grade porous iron mineral-based catalyst is 10-50 m². 2 / g, total iron content ≥40%, of which active Fe 2+ It accounts for 10%-30%.

5. The method for treating manganese-containing mining and metallurgical wastewater based on catalytic oxidation and self-precipitation technology using iron mineral-based materials according to claim 1, characterized in that, The ozone, under the action of an iron-based catalyst, forms a strong oxidizing free radical, which is the result of the ozone reacting with the Fe atoms in the iron-based catalyst. 2+ / Fe 3+ Under the influence of the active site, a chain decomposition occurs, which is directionally transformed into hydroxyl radicals, superoxide radicals and singlet oxygen.

6. The method for treating manganese-containing mining and metallurgical wastewater based on catalytic oxidation and self-precipitation technology using iron mineral-based materials according to claim 1, characterized in that, The homogeneous dissolution of the mineral phase reconstruction of the iron mineral-based catalyst refers to the heterogeneous dissolution of the original crystalline phase of the catalyst under the continuous action of ozone / free radicals. During the reconstruction process, Fe on the catalyst surface dissolves in ionic or colloidal state and dissociates into amorphous Fe(OH)3 and γ-FeOOH.

7. The method for treating manganese-containing mining and metallurgical wastewater based on catalytic oxidation and self-precipitation technology using iron mineral-based materials according to claim 1, characterized in that, The iron atoms are transformed and released into high-valence iron, which refers to Fe. 3+ The high-valence iron includes: free Fe 3+ Fe(OH)3 colloid and amorphous iron oxides, wherein the amorphous iron oxides include γ-FeOOH and FeOOH·nH2O, and the Fe in the iron mineral-based catalyst 2+ Under the action of ozone / free radicals, it is preferentially released and oxidized to Fe. 3+ .

8. The method for treating manganese-containing mining and metallurgical wastewater based on catalytic oxidation and self-precipitation technology using iron mineral-based materials according to claim 1, characterized in that, The manganese ion speciation refers to Mn 2+ Under the synergistic effect of ozone and free radicals, it is oxidized to MnO2 and permanganate (MnO4). - The MnO2 exists in the form of amorphous nanoparticles with a particle size of 10-50 nm and undergoes initial self-precipitation.

9. The method for treating manganese-containing mining and metallurgical wastewater based on catalytic oxidation and self-precipitation technology using iron mineral-based materials according to claim 1, characterized in that, The high-priced iron bridging network is formed by hydroxyl bridging to form "-Fe-O-Fe-". The "-Fe-O-Fe-" network traps MnO2 particles, heavy metal ions and residual suspended matter generated by oxidation to form a three-dimensional network aggregate flocculent, in which iron self-flocculation occurs and manganese iron ions undergo flocculation-coprecipitation reaction.

10. The method for treating manganese-containing mining and metallurgical wastewater based on catalytic oxidation self-precipitation technology using iron mineral-based materials according to any one of claims 1-9, characterized in that, The method for treating manganese-containing mining and metallurgical wastewater based on catalytic oxidation and self-precipitation technology using iron mineral-based materials is carried out in an integrated baffled reactor.

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