119 results about "Iron reduction" patented technology

The invention relates to a co-treatment process for high-iron red mud and various carbon-containing solid wastes. The co-treatment process comprises the working procedures of raw material preparation, ball pressing, drying and pre-reduction, iron reduction, titanium-silicon reduction, tailing treatment and the like. According to the method, the problems of low iron grade and high impurity aluminum content of a red mud iron recovery process are solved, the comprehensive utilization problem of other solid wastes and the utilization problem of tailings after extraction are synchronously realized, and the purpose of treating wastes with wastes is realized.

The invention provides a high-crystallinity modified iron oxide as well as a preparation method and application thereof, and relates to the technical field of organic solid waste treatment. The preparation method comprises the following steps: preparing a precursor MIL-88B by utilizing a hydrothermal method; the precursor MIL-88B is subjected to calcination treatment, and an iron oxide with the MIL-88B as the precursor is obtained; the temperature condition of the calcination treatment is 550-850 DEG C. The high-crystallinity modified iron oxide prepared by the preparation method improves methane production efficiency and stability, avoids competition of iron reducing bacteria, is stable in long-term operation and low in cost, and has both environmental and economic benefits.

The invention discloses an organic wastewater advanced treatment method and device with low agent input. The method comprises the following steps: an anaerobic biological iron-sulfur reduction reaction process: fully mixing elemental sulfur, ferric iron, iron-sulfur reduction sludge and wastewater containing organic carbon and organic pollutants with electronegative groups, carrying out anaerobic biological elemental sulfur reduction and iron reduction reactions, and directionally generating polysulfide and ferrous sulfide in situ; a nucleophilic substitution reaction process: carrying out nucleophilic substitution reaction on the organic pollutants with the electronegative groups and the polysulfide, and removing the electronegative groups to generate a reduced organic product; in the oxidation reaction process, ferrous sulfide reacts with dissolved oxygen to generate hydroxyl free radicals, the reduction state organic product is oxidized and degraded, and elemental sulfur and ferric iron are generated; and a sludge precipitation process: refluxing the precipitate to the anaerobic biological iron-sulfur reduction reaction zone, and discharging clarified water. The method provided by the invention realizes deep degradation and detoxification of refractory organic pollutants, and has the advantages of low agent investment, low cost and no secondary pollution.

The invention belongs to the technical field of electroplating wastewater treatment, and particularly relates to acidic electroplating wastewater treatment equipment and process based on combination of Fenton oxidation and acid-resistant nanofiltration membrane separation. Considering that the acidic nickel plating wastewater not only can provide acidic conditions, but also has ferrous ions, based on this, the acidic nickel plating wastewater is used as a raw material and is mixed with the ferrous ions and hydrogen peroxide for a Fenton reaction, and then iron ions and nickel ions are separated by adopting a PP precision filter and an anti-high-turbidity ultrafiltration system. According to the method, iron ions are recycled after being reduced by an iron reduction reactor, nickel ions are separated by adopting an acid-resistant nanofiltration system, and the obtained nickel ions are subjected to electroplating and water recycling again, so that the technical defects existing in the traditional nickel plating wastewater treatment are overcome, and the utilization of the acidic nickel plating wastewater is realized.

The present invention provides a Fenton iron sludge treatment method and device, comprising the following steps: allowing the Fenton iron sludge to enter an iron reduction unit, undergoing reduction treatment under the action of dissimilatory iron-reducing bacteria, reducing the trivalent iron in the Fenton iron sludge to divalent iron through the reduction treatment to obtain reduced iron sludge; allowing at least a portion of the reduced iron sludge to enter a bioleaching unit, undergoing bioleaching treatment under the action of specific microorganisms to obtain a first mixed liquid; dehydrating the first mixed liquid to obtain an aqueous phase and dehydrated sludge, respectively; and returning the aqueous phase to the bioleaching system to participate in the bioleaching treatment. The present invention can solve technical problems existing in the prior art, such as the need for additional acid, the generation of a large amount of strongly acidic water, the susceptibility to environmental pollution, the inability to recycle iron, and high costs.

The invention discloses an organophosphorus degradation and synchronous recovery system based on a double-cathode induced electro-Fenton reaction. An induced iron electrode plate and an electrochemical assembly with double cathode plates are arranged in an electrolytic tank; the double cathode plates are a gas diffusion cathode plate and an iron reduction cathode plate; the gas diffusion cathode is used for reducing oxygen to generate hydrogen peroxide, the induction iron electrode releases ferrous ions under the action of an electric field, the ferrous ions and the hydrogen peroxide are subjected to a Fenton reaction, organic phosphorus is degraded into PO4 < 3->, Fenton reaction by-products Fe < 3 + > and PO4 < 3-> form iron phosphorus precipitates, and degradation of the organic phosphorus and synchronous recovery of orthophosphate are realized; excessive Fe < 3 + > is adsorbed by the iron reduction cathode and is further reduced into Fe < 2 + > which enters the solution again to participate in the Fenton reaction, so that the reaction efficiency is improved, and Fe < 3 + > / Fe < 2 + > circulation is promoted while slow release of iron is realized. The device is simple in structure, low in maintenance cost and high in operability, and the purpose of efficiently recycling phosphorus resources is achieved.

The invention discloses a method for efficiently extracting iron from copper slag through non-molten hydrogen reduction, and belongs to the technical field of green resource utilization of metallurgical solid waste. Hydrogen is introduced to carry out reduction roasting on copper slag pellets, and a reduction auxiliary is added in a matched mode to dissociate fayalite in the copper slag; the purposes of strengthening the hydrogen reduction effect and improving the metal iron reduction rate are achieved, magnetite, fayalite and iron elements in other iron-containing silicate phases in the copper slag are reduced into metal iron, meanwhile, reduction products are treated through ore grinding and magnetic separation, and the iron ore concentrate grade is effectively improved. The method has the characteristics of simple reduction process and low carbon emission, and has high economic benefits.

The invention discloses a mariculture area bottom mud aging degree identification and restoration method, belongs to the technical field of aged bottom mud restoration, can quantitatively evaluate the aging degree of mariculture bottom mud by using sulfide, heavy metal and organic carbon as indexes, and solves the problem that the current aging judgment standard does not have a unified standard. A scientific basis is provided for repairing the aged bottom mud and evaluating the repairing effect; meanwhile, the developed iron-reducing flora loaded nZVI / S composite material (DIRB at nZVI / S) can be used for removing sulfides, heavy metals and organic matters in the mariculture bottom mud in an immobilization manner by utilizing a physical-chemical-biological combined effect, so that effective repair of the aged mariculture bottom mud is realized.

This application proposes a method for enhancing the smelting of iron-based minerals in a molten pool. The method includes introducing a first reducing agent, fuel, and oxygen-enriched gas into a jet melting zone to melt the added iron-based minerals and flux, and partially pre-reducing the molten slag, with weakly reducing flue gas being discharged. The molten slag then enters a jet reduction zone, where a second reducing agent is added, and fuel and oxygen-enriched gas are submerged and injected into the zone, initially reducing the molten slag to produce molten iron, iron-containing slag, and strongly reducing flue gas. The strongly reducing flue gas is treated to obtain CO gas, which is then pressurized and introduced into the jet melting zone; and / or, the CO gas is pressurized and introduced into the jet reduction zone. This application can effectively process iron-containing minerals and low-sulfur iron-containing slag, and features efficient iron reduction, efficient energy recycling, and low cost.

The present application relates to the technical field of soil remediation, and discloses a composite microbial inoculum for activating reverse conversion of oxidized iron in dry land soil and application thereof.The composite microbial inoculum comprises aerobic iron-reducing bacteria and phenazine electron shuttles.The present application mediates the aerobic iron-reducing process of the aerobic iron-reducing bacteria strain through the phenazine electron shuttles, significantly improves the electron transfer efficiency, enhances the iron-reducing capacity, and can efficiently generate high-activity weak-crystalline iron oxide under aerobic conditions, thereby breaking through the limitation of traditional iron reduction relying on anaerobic environment;by promoting the reverse conversion of high-crystalline oxidized iron to weak-crystalline oxidized iron, the mineral interface activity is improved, the fixation capacity for Cd, Pb, As and other multi-metals in dry land soil is significantly enhanced, the biological availability thereof is reduced, the biological toxicity and migration risk thereof are greatly weakened, the remediation process is stable, the risk of secondary pollution is low, and the present application has good application prospect and popularization value in the field of heavy metal contaminated soil remediation.

The invention relates to the technical field of preparation of environmental functional materials, and discloses a directional synthesis method of magnetic porous iron-doped graphitized biochar, which is realized by the following steps: cooperatively inducing low-temperature graphitization by utilizing a biomass endogenous S < 2 > self-template and nano-diamond; performing double-complexing ultrasonic impregnation on the iron precursor to realize nanoscale dispersion; performing staged pyrolysis, pre-carbonizing in an inert atmosphere to construct a carbon skeleton, and synchronously completing iron reduction and graphitization in a reducing atmosphere; performing mixed pickling to synchronously remove the template and construct a passivation layer; and finally, carrying out magnetic separation to obtain the high-porosity and uniformly iron-doped magnetic graphitized charcoal. A graphitized porous structure is realized through cooperation of a low-temperature self-template and nano-diamond, iron agglomeration is inhibited through a double-complexing ultrasonic technology, a protective layer and active sites are synchronously constructed through mixed pickling and passivation, and three technical barriers of high-temperature collapse, iron particle inactivation and short cycle life of a traditional process are broken through.

The invention discloses an advanced treatment and recycling method for lead-zinc beneficiation wastewater based on biological reduction, and belongs to the technical field of beneficiation wastewater treatment.The method comprises the following steps that the lead-zinc beneficiation wastewater is sequentially subjected to flocculent precipitation and CO2 hardness reduction pretreatment, heavy metal and COD removal through a bioelectrochemical system, methanol generation and advanced oxidation deep COD removal; and neutralizing, precipitating and removing iron and sulfate radicals to obtain treated water, and carrying out dissimilatory iron reduction treatment on the water-containing iron sludge for advanced oxidation. According to the method, CO2 and iron resources can be recycled, COD and heavy metal in the wastewater are deeply removed, the hardness and sulfate radicals are remarkably reduced, and the treated water can be completely recycled to a mineral separation procedure or discharged after reaching the standard.

The present application belongs to the technical field of soil environment regulation, and particularly relates to a paddy soil carbon fixation and emission reduction regulation method based on a ferrihydrite-organic matter complex. The ferrihydrite-organic matter complex is prepared through coprecipitation, the mineral combination degree of organic carbon in soil is improved, and the biological availability thereof is reduced, so as to alleviate the process of organic carbon decomposition and greenhouse gas emission mediated by microorganisms. Under the condition of redox fluctuation, the complex can maintain good structural stability, slow down the process of iron reduction and dissolution and the process of organic carbon release accompanying the same. In addition, the ferrihydrite as an electron acceptor can participate in the electron competition process under anaerobic conditions, so as to inhibit the production of methane to a certain extent. Therefore, the ferrihydrite-organic matter complex can realize the synergistic regulation of organic carbon stabilization and greenhouse gas emission reduction in paddy soil.

The invention discloses a preparation method and application of an electrode of bioelectrochemical equipment. The method comprises the following steps: S1, pretreatment; s2, preparing a polyvinyl alcohol solution; s3, preparing electrode slurry; s4, coating is carried out; and S5, drying. The electrode is used for treating chlorophenol wastewater. The electrode provided by the invention is prepared by modifying zero-valent iron, is arranged in an anode region of a bioelectrochemical reactor, and can effectively regulate and control oxidation-reduction potential, strengthen electron transfer between iron reducing bacteria and acetogenic bacteria at an anode and enrich acetogenic flora by loading trace zero-valent iron, so that the yield of acetic acid in an acidogenic phase is increased; the synchronous pollutant removal and methane yield increase are realized, and the economic benefit is improved.

The application discloses a method for promoting paddy field biological nitrogen fixation based on long-distance electron transfer, and comprises the following steps: S1, soil pretreatment, establishing a flooding system; S2, pre-incubation to form a stable redox stratification; S3, constructing a long-distance electron transfer channel; S4, cultivation: under the conditions of flooding and a certain temperature, continue to cultivate to promote the paddy field biological nitrogen fixation in the flooding system. The application does not need an external power supply, only by arranging a graphite rod in the flooded paddy field soil, making it span the surface layer oxidation zone and the lower layer reduction zone, forming a long-distance electron transfer channel, thereby realizing the directional transport and utilization of the lower layer reduction equivalent to the surface layer, providing continuous support for the surface layer nitrogen fixation process from the electron supply end, promoting the nitrogen fixation process, and also promoting the enrichment of paddy field biological nitrogen fixation related microbial groups in the surface layer oxidation zone and changing the iron valence state distribution, promoting the transformation of Fe(III) into Fe(II), and enhancing the coupling of iron reduction and nitrogen fixation process.

The invention provides a composite repairing agent capable of synchronously removing heavy metal cadmium and neonicotinoid pesticides and a preparation method and application of the composite repairing agent. The composite repairing agent comprises a functional fungicide and iron minerals, and the ratio of the dry weight of the iron minerals to the volume of a fungicide liquid of the functional fungicide is 1: (1-10); the functional microbial agent is a viable bacterium culture of dissimilatory iron reducing bacteria, the thallus concentration of the functional microbial agent is not lower than 1 * 10 < 8 > CFU / mL, and the iron mineral is Fe2O3.nH2O. According to the method, an iron reducing bacteria-ferrihydrite mixed system formed by in-situ active minerals is constructed, efficient treatment of combined pollution is achieved through an adsorption-conversion-degradation synergistic mechanism, and ferrihydrite is converted into magnetite in situ within 24-72 hours through iron reducing bacteria in the iron reducing bacteria-ferrihydrite; the new magnetite shows excellent dual functions, and the removal rate of Cd can be increased to gt by crystal lattices of the new magnetite through obligate adsorption and coprecipitation; meanwhile, structural ferrous iron is used as a strong reducing agent and can efficiently attack nitryl in imidacloprid molecules, and gt, gt, gt, gt, gt, gt and gt are achieved; the degradation rate is 90%.

The invention relates to the technical field of nano zero-valent iron wastewater treatment, and discloses a method for in-situ regeneration and inactivation of nZVI through electron beam irradiation and a nano zero-valent iron membrane, the electron beam irradiation and the nano zero-valent iron (nZVI) membrane are cooperated to construct a green long-acting treatment system for Cr (VI)-containing wastewater: the wastewater is controlled to flow through a high-dispersion nZVI membrane in a thin-layer advection mode, and the Cr (VI)-containing wastewater is subjected to in-situ regeneration and inactivation; and meanwhile, electron beam irradiation is received, strong reducing particles such as hydration electrons (eaq-) and hydrogen free radicals (. H) generated by irradiation can carry out in-situ reduction on inactivated nZVI, Fe (0) or part of Fe (II) can continuously play a reducing role, and the long-acting effect of the system for treating Cr (VI)-containing wastewater is achieved together with synchronous intensified reduction of irradiation on Cr (VI). According to the method, the wastewater treatment capacity in unit time can be remarkably improved, meanwhile, the irradiation energy consumption and the nZVI use amount are reduced, efficient circulation of the iron reduction effect is achieved, and iron sludge pollution is greatly reduced.

The present invention discloses a method for preparing an iron-based catalyst, comprising the following steps: (1) drying, grinding, and screening a red mud raw material and a biochar raw material; (2) mixing the red mud particles obtained in step (1) with the biochar particles in a certain proportion; (3) charging the mixture in step (2) into a fixed bed reactor, introducing a gas containing carbon dioxide into the reactor, and performing an activation treatment; (4) cooling the reactor to room temperature, removing the mixture after the reaction, washing it with water, and drying it to obtain an iron-based catalyst. The present invention treats two solid waste materials, red mud and biochar, together, expands and modifies the biochar at high temperature using red mud, and reduces and loads iron onto the modified biochar. The method has low cost, a simple preparation method, and can be produced on a large scale.

The present invention relates to iron removal from silica sand, and specifically to a biological reduction method and system for iron removal from silica sand. By using Shewanella sp. bacteria to reduce crystalline iron, and simultaneously improving the iron removal rate through the synergistic effect of sodium lactate, sulfur-containing compounds and electron mediators, and accelerating the iron removal speed by washing with organic acids. Compared with the existing methods, the biological reduction method for iron removal from silica sand of the present invention can not only effectively remove crystalline iron in silica sand, but also recycle Shewanella sp. bacterial liquid and organic acid solution.

The application discloses a PRB magnetic bioactive carbon permeable wall electrode plate carbon felt adsorption layer double adsorption structure and application, and relates to an electrode plate carbon felt adsorption layer double adsorption structure and application. The application is aimed at solving the problems of limited soil quantity for processing each time and high cost of existing soil heavy metal removal methods, and the structure of the application comprises a first polyethylene net fixed layer, an activated carbon zero-valent iron reduction layer, a magnetic biochar adsorption layer and a second polyethylene net fixed layer, wherein one side of the second polyethylene net fixed layer is connected with the magnetic biochar adsorption layer, and the other side is connected with the electrode plate surface carbon felt adsorption layer. The application is applied to an electrolyte circulation technology reinforced electromotive force soil heavy metal removal device. The application has the characteristics of no secondary pollution and simple operation, has good removal efficiency for heavy metals and organic pollutants in low-permeability and multi-phase inhomogeneous soil media, and has low overall cost. The application belongs to the field of soil heavy metal remediation.

The invention provides a geotrophic bacterium SG265 and application thereof, and belongs to the technical field of microbial agents. The geotrophic bacteria SG265 disclosed by the invention is preserved in Guangdong Microbial Culture Collection Center on May 7, 2025, the preservation number is GDMCC No: 66266, and the geotrophic bacteria SG265 is named as Geotalea sp. In taxonomy. The terrestrial nutrient bacteria SG265 are anaerobic nitrogen-fixing bacteria, have iron reduction and nitrogen fixation functions at the same time, can reduce nitrogen into nitrogen fertilizer available for crops under the anaerobic condition, can greatly increase the content of available nitrogen in soil, can effectively promote rice growth, can reduce the application amount of the nitrogen fertilizer, can reduce environmental pollution, and can improve the yield of rice. The method has a good application prospect in agricultural production.

The present application belongs to the technical field of comprehensive utilization of waste lithium-ion power battery, and particularly relates to a method for obtaining battery-grade iron phosphate from waste lithium iron phosphate battery. After acid leaching of the waste battery, the divalent iron is completely converted into trivalent iron by an oxidizing agent, and then an ether extractant is added for multiple extractions. The organic phase after extraction is calcined in a furnace. The ether extractant in the reaction can be used as an extractant to extract iron from the aqueous phase, and can also generate reducing carbon monoxide or carbon at high temperature to reduce part of the iron, so as to obtain magnetite. The magnetite is calcined in a tube furnace, the iron is first converted into magnetite, and then the separation of iron and other metal impurities is realized by a magnet, so that more pure battery-grade iron phosphate is obtained.

The application relates to the field of solid pollutant treatment, in particular to a desulfurizer and a method for solid-state desulfurization treatment of high-sulfur pyrite; the desulfurizer comprises desulfurization ash and coal, and the mass ratio of the desulfurization ash and the coal is 1.5-2.5:1; the method comprises the following steps: roasting high-sulfur pyrite and the desulfurizer in the first aspect to simultaneously perform desulfurization and iron reduction of the high-sulfur pyrite, so as to obtain an iron-containing mixture; performing magnetic separation on the iron-containing mixture to obtain metallic iron; by means of the combination of the desulfurization ash and the coal, CaSO4 in the desulfurization ash serves as an oxygen carrier to oxidize and desulfurize S in the low-valence state in the high-sulfur pyrite, meanwhile, the coal can perform a reduction reaction with the iron ore after desulfurization, and the ratio of the desulfurization ash and the coal is controlled, so that sufficient coal participates in the reduction reaction under the premise of sufficient desulfurization, thereby realizing the synchronous performance of the desulfurization and reduction of the high-sulfur pyrite only by means of the desulfurizer.

The invention belongs to the field of rare earth resource recovery, and particularly relates to a method for selectively leaching scandium in rare earth iron-rich minerals, which comprises the following steps: adding a reducing agent A and a sodium-based activator B into the rare earth iron-rich minerals, and then carrying out heat preservation roasting treatment at the temperature T for the heat preservation time t, so that iron in the rare earth iron-rich minerals is reduced into metal iron; the activation of scandium and the conversion of rare earth to an insoluble double salt form are synchronously realized; the reducing agent A can be lignite and the like; the sodium-based activating agent can be sodium carbonate and the like; the temperature T ranges from 950 DEG C to 1100 DEG C; the time t is 1 to 2 hours. The invention further comprises a scheme of roasting mineral grinding-magnetic separation of iron and an acid leaching scheme of the activated scandium-containing rare earth material. According to the activation method, reduction of iron and efficient leaching of scandium can be achieved, meanwhile, rare earth elements are promoted to be converted into an indissolvable form, and therefore efficient separation of scandium and other rare earth is achieved, and the follow-up separation difficulty is remarkably reduced.

The application discloses a system and method for purifying biogas based on Fenton iron sludge anaerobic digestion, and belongs to the technical field of solid waste resource utilization in wastewater treatment processes. The application utilizes the fact that Fenton iron sludge can produce fermentation iron sludge rich in Fe(II) through dissimilatory iron reduction in an anaerobic environment, and biogas to be purified is introduced into the fermentation iron sludge, so that CO2 in the biogas penetrates into the liquid phase and reacts with Fe(II) to produce FeCO3, while the CO2 is fixed in the form of carbonate, and the biogas is purified and the CO2 impurities are removed. Meanwhile, FeCO3 as a cheap iron salt can be recycled in the process of industrial production, such as participating in sewage coagulation and improving sludge activity, and can also be used as a soil conditioner and an iron fertilizer to improve soil structure and be used in agricultural production, so that the problem of resource utilization of Fenton iron sludge is solved.

The present invention provides a method for resource recovery of chromium-containing electroplating sludge, including the process steps of pigment preparation and metal recovery. Among them, the ceramic pigment is prepared by a solid-phase method using chromium-containing electroplating sludge and calcium-silicon substances as raw materials. The waste liquid generated during the preparation process realizes the cascade recovery of metals through the methods of adding iron powder to reduce and precipitate copper, hydrogen peroxide to oxidize and precipitate iron, and reduction and flocculation to precipitate chromium. The recovered chromium hydroxide can be returned to the raw material electroplating sludge for secondary utilization. The present invention prepares a ceramic pigment with good color rendering effect and excellent acid and alkali resistance through a simple solid-phase reaction method. Moreover, the purity of the grossularite phase Ca3Cr2(SiO4)3 is relatively high, with stable properties, acid and alkali resistance, and at the same time realizes the cascade recovery of metals. The present invention realizes the resource utilization of chromium-containing sludge, a solid hazardous waste, in the field of ceramic pigments. The process is simple, easy to control, environmentally friendly, and the raw materials are cheap and easily available, greatly reducing the production cost and having good economic and environmental benefits.

The present invention provides a strain of geotrophic bacteria SG265 and its application, belonging to the technical field of microbial agents. The geotrophic bacteria SG265 of the present invention was deposited in Guangdong Province Microbiological Culture Collection Center on May 7, 2025, with the deposit number GDMCC No: 66266, and its taxonomic name is Geolocation sp. The geotrophic bacteria SG265 of the present invention is an anaerobic nitrogen-fixing bacterium with both iron reduction and nitrogen fixation functions. It can reduce nitrogen gas into nitrogen fertilizer that can be used by crops under anaerobic conditions. It can significantly increase the content of available nitrogen in the soil, effectively promote rice growth, reduce the amount of nitrogen fertilizer applied, and reduce environmental pollution. It has good application prospects in agricultural production.

This invention belongs to the field of wastewater treatment technology, specifically relating to a method for preparing a sponge iron-based ferrous silicate reducing agent for wastewater treatment. Sponge iron is activated in a dilute phosphoric acid solution to obtain activated sponge iron; the activated sponge iron is washed and then immersed in a ferrous solution, removed and washed, and then matured in a sodium silicate solution to obtain matured sponge iron; the matured sponge iron is washed and freeze-dried to obtain the sponge iron-based ferrous silicate reducing agent. The sponge iron-based ferrous silicate reducing agent prepared by this invention is easily separated from the effluent and has excellent and long-lasting reducing performance. It solves the problems of high reducing agent dosage, high salinity of the treated effluent, generation of large amounts of iron sludge, and the need for continuous addition of reducing agent in traditional reduction processes. Furthermore, the preparation method is simple, requiring no complex equipment or catalysts, and the raw material, sponge iron, is inexpensive and widely available, resulting in low production costs and suitability for large-scale preparation and engineering applications.

The invention provides a method and a device for multi-stage reduction of iron by utilizing natural gas graded reforming, and belongs to the technical field of energy conservation, emission reduction and hydrogen energy ironmaking. The method for multi-stage reduction of iron by using natural gas fractional reforming comprises the following steps: performing natural gas fractional reforming in a gas production unit, wherein hydrogen and carbon monoxide are produced step by step by using a methane cracking reaction and a carbon-carbon dioxide neutralization reaction; according to the reaction characteristics of different reduction stages of the original iron oxide, hydrogen and mixed gas of hydrogen and carbon monoxide in different proportions are supplied to different reduction stages of the original iron oxide so as to carry out a multi-stage iron reduction reaction, and elemental iron is obtained; wherein in the multi-stage reduced iron reaction, the valence state of the original iron oxide is gradually reduced until zero-valence-state elemental iron is obtained.

The present application belongs to the technical field of water pollution treatment, and relates to microbial treatment, in particular to an aged iron filings promoted aerobic iron-reducing fungi for denitrification and application thereof. Aspergillus The aerobic iron-reducing fungi is classified and named as sp. R4, and is preserved in China Center for Type Culture Collection on February 13, 2025, with a preservation number of CCTCC NO: M 2025217. Aquabacter cavernae 1-5 are products obtained by iron filings oxidation in the process of denitrification. The present application provides a new insight for the repair of low carbon-nitrogen ratio water body.