816 results about "Reducing atmosphere" patented technology

The invention belongs to the technical field of powder metallurgy, and particularly relates to high-performance tungsten carbide and a preparation method thereof. A preparation method of medium-coarse tungsten carbide comprises the following steps that tungsten oxide is subjected to high-temperature reduction through a reverse hydrogen reduction method, and tungsten powder is obtained; and the tungsten powder is subjected to carbon blending, uniform mixing and high-temperature carbonization in a reducing atmosphere, a product is pre-crushed and then subjected to airflow crushing, and the tungsten carbide is obtained. According to the preparation method of the medium-coarse tungsten carbide, the particle size of the prepared tungsten carbide is 1-3 microns, the total carbon content is 6.12-6.18%, the combined carbon content is larger than or equal to 6.10%, the free carbon content is smaller than or equal to 0.06%, the oxygen content is smaller than or equal to 0.12%, and the impurity content is smaller than 0.5%; the particle size distribution is narrow, the particles are uniform, and the performance of the tungsten carbide powder is greatly improved.

The invention provides a method for providing composite luminescent particles, comprising: (a) providing (i) a luminescent material, comprising (A1-xBx)3(C1-yDy)5O12 nanoparticles or a precursor therefor, wherein A comprises one or more of yttrium, lutetium, gadolinium, lanthanum; B comprises one or more rare earth elements; C comprises one or more of aluminum, gallium, and scandium; D comprises one or more transition metal ions; and wherein 0≤x≤1, 0≤y≤1, and x+y>0; and (ii) further providing a precursor of an oxide material, wherein said oxide material has a melting point of at least 850°C; (b) mixing said (i) luminescent material comprising (A1-xBx)3(C1-yDy)5O12 nanoparticles or a precursor therefor and (ii) said precursor of an oxide material; (c) curing said precursor of said oxide material to obtain a cured particle, said cured particle comprising said luminescent material, and a coating of said oxide material; (d) heating said cured particle at a first temperature for a first duration, wherein said first temperature is 600 °C or higher, wherein said first duration is 10 minutes or more; and (e) heating said cured particle under a reducing atmosphere comprising carbon monoxide at a second temperature for a second duration, wherein said second temperature is 700 °C or higher, and wherein said second duration is 1 hour or more.

The invention discloses a flash and top blowing coupled molten pool tin smelting device and method, and belongs to the technical field of pyrogenic smelting of crude tin. Tin concentrate, fuming enriched tin middling and powdery tin smoke dust are subjected to ore blending with a flux and then are smelted; adding a carbonaceous reducing agent into the molten pool, and reducing to form a CO reducing atmosphere layer at the upper part of the slag layer; and blowing fluidized bed furnace roasting dry powder to the upper part of the CO reducing atmosphere layer, carrying out flash reduction smelting on the fluidized bed furnace roasting dry powder, enabling the fluidized bed furnace roasting dry powder which is not subjected to flash reduction smelting to enter a molten pool, and continuing to carry out a reduction stage in top-blowing molten pool smelting, so that flash and top-blowing coupling is realized, and crude tin is prepared. According to the invention, flash melting pool smelting and top-blowing melting pool smelting are effectively coupled together, fuel consumption can be reduced by about 20%, and the bed capacity is obviously improved.

The invention provides a production process for stably controlling adhesive force of a DP steel zinc layer. The production process comprises the following steps: step 1, setting a heating section 1, a heating section 2 and a furnace nose section in a total radiation heating annealing furnace; 2, according to the model and thickness of DP steel, target dew points of a first heating section, a second heating section and a furnace nose section are set; 3, according to the target dew points set in the first heating section, the second heating section and the furnace nose section in the step 2, water vapor is put into the protective gas for humidification, and the water vapor reacts with Si, Mn and Cr elements enriched on the surface of the steel plate to generate volatile oxides; the dew point of the annealing furnace is precisely controlled in a segmented mode, different humidification modes are adopted, and the surface state is controlled, so that surface oxide residues are reduced, cleanliness of a steel substrate is guaranteed, and the binding force of a zinc layer is improved; the iron oxide layer formed on the surface of the steel plate enters a reducing atmosphere annealing furnace containing hydrogen, the hydrogen can reduce the iron oxide layer on the surface of the steel plate to form a reduced iron layer, and the adhesive force of a zinc layer is improved.

The invention relates to the technical field of solar cells, in particular to copper-based paste, a TOPCon cell and a preparation method of the TOPCon cell. The copper-based slurry includes: copper powder as main powder densified in a sintering process to form a conductive phase; the hydrogen storage material is used for releasing a hydrogen element in the sintering process and locally forming a reducing atmosphere so as to prevent the copper powder from being oxidized; the hydrogen storage material comprises a liquid hydrogen storage material; and the organic carrier provides fluidity and thixotropy for the slurry. Compared with solid hydrogenated metal particles, the liquid hydrogen storage material can be more uniformly dispersed in the copper-based slurry and can coat the copper powder, so that the hydrogen element released from the copper-based slurry is more uniform, and the oxidation of the copper powder can be comprehensively inhibited. Meanwhile, the dehydrogenation amount of the liquid hydrogen storage material is far higher than that of the solid hydrogenated metal particles, the release amount of hydrogen elements can be increased by multiple times under the same mass, and then more sufficient oxidation protection is provided for the copper powder.

The invention discloses a biological carbon / graphene composite material as well as a preparation method and application thereof. The method comprises the following steps: impregnating a biomass raw material with a copper salt solution to obtain a precursor; the precursor is pyrolyzed to obtain a copper oxide modified biological carbon material, then under the conditions of reducing atmosphere and high temperature, carbon dioxide serves as a carbon source, graphene is generated on the copper oxide modified biological carbon material in situ, the biological carbon / graphene / copper composite material is obtained, and the biological carbon / graphene / copper composite material is subjected to copper leaching treatment to obtain the graphene / copper composite material. Obtaining a finished product. The composite material has excellent electrochemical performance, and has excellent rate capability, capacitance and long cycle service life when being used for preparing a capacitor. The preparation method is simple, low in cost and suitable for industrial production.

The invention relates to the technical field of chemical catalysis, in particular to a copper-silicon catalyzed cyclohexanol gradient dehydrogenation and hydrogen recycling method which comprises the following steps: step 1, preparing a gradient catalyst, namely carrying out surface hydroxyl regulation pretreatment on porous silica gel, and loading a copper salt solution by adopting a step-by-step impregnation method to form gradient distribution with gradually decreased copper loading capacity from outside to inside, carrying out segmented heating reduction in a reducing atmosphere containing 5vol% of H2 / N2; 2, gradient dehydrogenation reaction process control; and 3, hydrogen in-situ separation and cyclic utilization: separating hydrogen from the reaction outlet gas through a palladium alloy membrane, controlling the pressure difference of the two sides of the membrane to maintain the permeation flux, returning the separated hydrogen to the inlet of the reactor to adjust the hydrogen partial pressure, and storing the residual hydrogen. Through gradient catalyst preparation, accurate reaction process control and efficient hydrogen recovery technologies, the cyclohexanone production efficiency is improved, and long-term stability of the catalyst and efficient recycling of hydrogen are achieved.

The invention discloses a nitrogen-doped carbon material composite tin-antimony alloy oxygen reduction reaction catalyst. The nitrogen-doped carbon material composite tin-antimony alloy oxygen reduction reaction catalyst comprises a nitrogen-doped carbon material carrier and tin-antimony alloy particles uniformly loaded on the surface and inside of the nitrogen-doped carbon material carrier. The preparation method comprises the following steps: S1, dissolving a precursor of a nitrogen-containing carbon material in an organic solvent to obtain a precursor solution; s2, adding a template agent into the precursor solution until the template agent is completely dispersed, then adding soluble salt of tin and soluble salt of antimony, and uniformly stirring to obtain a raw material solution; and S3, carrying out freeze drying treatment on the raw material solution, then introducing the raw material solution into a reducing atmosphere, carrying out high-temperature calcination treatment, and then carrying out washing treatment to remove the template agent. The invention discloses a nitrogen-doped carbon material composite tin-antimony alloy oxygen reduction reaction catalyst which is novel in composition, has a good pore structure and a high specific surface area, and not only has excellent oxygen reduction reaction catalytic activity, but also has relatively high stability.

The invention discloses a method for improving corrosion resistance of steel, and belongs to the technical field of metal protection. The method for improving the corrosion resistance of the steel comprises the following procedures of acid pickling, rinsing, drying, reduction, hot dipping, passivation, drying and packaging. Replacing a plating assisting process in the hot dipping process with a thermal reduction process; and in the thermal reduction process, hydrogen with the volume content of 3-25% is adopted for thermal reduction. A plating assisting technology in a traditional hot dipping technology is replaced with a reduction technology, the steel obtained after acid pickling is dried and then fed into the atmosphere box, a small amount of iron oxide remaining on the surface of the steel is reduced into sponge iron in the hydrogen reduction atmosphere, the surface of the steel keeps active, and then a zinc-based or zinc alloy plating layer can be better plated; therefore, the corrosion resistance of the steel is greatly improved, and the service life is prolonged.

The invention belongs to the technical field of ceramic materials, and relates to high-thermal-conductivity silicon nitride ceramic and a preparation method thereof. The invention discloses a preparation method of high-thermal-conductivity silicon nitride ceramic, which comprises the following steps: (1) uniformly mixing silicon powder and a sintering aid to obtain mixed powder, and carrying out compression molding on the mixed powder to obtain a silicon blank; the sintering aid is a rare earth metal oxide; (2) placing the silicon blank in a nitrogen-containing reducing atmosphere environment, pre-treating at 600-1180 DEG C, heating to 1350-1700 DEG C, and carrying out nitriding treatment to obtain a silicon nitride blank; and (3) placing the silicon nitride green body in an inert atmosphere, and sintering at 1800-2200 DEG C to obtain the silicon nitride ceramic. The pretreatment step is added before the nitridation reaction, so that silicon dioxide impurities wrapped on the surface of the silicon powder are effectively eliminated, and the oxygen content in a liquid phase is reduced on the basis of not reducing the total content of a sintering aid, so that a silicon nitride blank with low lattice oxygen content is more easily prepared, and the heat conductivity of the silicon nitride ceramic is improved.

The invention relates to a process for extracting iron from red mud by using hydrogen reduction and electrolysis technologies, the red mud is a by-product generated in the industrial production process of aluminum, the environmental burden caused by the by-product can be solved, the carbon emission can be reduced, and the development of a green metallurgical technology can be promoted. Comprising the following steps: conveying red mud serving as a raw material into a rotary furnace, conveying hydrogen serving as a reducing medium into the rotary furnace, enabling iron oxide in the red mud to form hydrogen reduced iron in a furnace heating state and a hydrogen reducing atmosphere, conveying the red mud containing the hydrogen reduced iron into a sulfuric acid solution, the hydrogen reduced iron is dissolved in the sulfuric acid solution to form a sulfuric acid solution containing iron ions, the sulfuric acid solution containing the iron ions serves as an electrolyte in an electrolysis device, and electrolytic pure iron formed by electrolytic deposition of the iron ions is obtained through the electrolysis device.

The invention relates to a nano silicon carbide whisker and a preparation method thereof, and the preparation method comprises the following steps: (1) carrying out acid process treatment on fly ash by using an acid solution, so that the content of key impurity elements in the fly ash accounts for 2-11% of the total mass of the treated fly ash, and obtaining acid-treated fly ash; (2) mixing the acid-treated fly ash with a first carbon source to obtain a mixture; and (3) covering the mixture with a second carbon source, roasting in a reducing atmosphere to obtain a roasted material which comprises a nano silicon carbide whisker layer and a total impurity layer positioned below the silicon carbide whisker layer, and removing the total impurity layer to obtain the nano silicon carbide whisker. According to the preparation method, the low-cost fly ash is taken as a raw material, the advantages of low preparation cost and relatively high product yield can be taken into account through the synergistic effect of moderate acid treatment, raw material position setting and roasting in the reducing atmosphere, and good morphology and relatively high purity of the nano silicon carbide crystal whiskers are ensured.

The application discloses a platinum-based high-entropy intermetallic compound and a preparation method and application thereof as a hydrogen fuel cell cathode catalyst, and belongs to the field of fuel cells.The preparation method comprises the following steps: S01, adding platinum salt, at least five other metal salts and a nitrogen-rich organic compound into an organic solvent, uniformly mixing, and obtaining a metal precursor mixed solution; S02, adding a carbon carrier into the metal precursor mixed solution, fully mixing, drying, collecting, and obtaining a precursor; and S03, heat treating the dried precursor under a reducing atmosphere, and performing heat preservation treatment, so as to obtain the platinum-based high-entropy intermetallic compound.The preparation method is simple, low in cost and good in repeatability, the prepared catalyst has the advantages of uniform particle size and high oxygen reduction activity, and has a good development prospect in the field of hydrogen fuel cell catalyst applications.

The invention belongs to the technical field of catalytic materials and hydrocarbon reforming, and particularly relates to a high-entropy catalyst as well as a preparation method and application thereof. The preparation method comprises the following steps: mixing a metal salt solution containing lanthanum, chromium, copper, zinc, manganese, nickel, iron and cobalt ions with a chelating agent and a dispersing agent for reaction, carrying out ultrasonic cavitation treatment to obtain sol, adjusting the pH value, gelatinizing under an oil bath heating condition to obtain a colloidal precursor, drying, and calcining in an air atmosphere to obtain a perovskite type high-entropy oxide precursor; and then treating in a reducing atmosphere to obtain the FeZnCuNiCo perovskite type high-entropy alloy catalyst which contains metal components of La, Cr, Ni, Mn, Fe, Zn, Cu and Co and takes a multi-metal alloy active center of Fe-Zn-Cu-Ni-Co as a main component. The high-entropy catalyst can meet the harsh requirements of high temperature, strong carbon deposition driving force and long-period operation in a propane dry reforming reaction, and is suitable for industrial application scenarios of continuous production of high-temperature synthesis gas.

The invention provides a preparation method of a high-entropy alloy catalyst, which comprises the following steps: weighing at least five metal precursors such as iron, nickel, cobalt, magnesium, aluminum, niobium and tungsten according to a certain molar ratio, premixing solid powder by a mechanical ball milling method, filling the mixed powder into a crucible of an electric arc melting furnace, placing a reaction device in an inert atmosphere, and carrying out ball milling to obtain the high-entropy alloy catalyst. And material oxidation is prevented. Through arc discharge, the raw materials are melted in a rapid heating mode, and meanwhile in the melting process, electromagnetic stirring is used for ensuring that the materials are fully mixed and homogenized. And after smelting is completed, a melt is rapidly cooled and solidified under the action of a cooling system, after a sample is completely cooled, the crucible is taken out, thermal reduction is conducted in a reducing atmosphere, and the ammonia decomposition high-entropy alloy catalyst is obtained. The catalyst prepared by the invention has the characteristics of high activity, short preparation process time and high homogenization degree.

A manufacturing method for a non-oriented silicon steel sheet, comprising the working procedures of slab continuous casting, slab heating, intermediate slab manufacturing, surface treatment, slab assembly, heating, hot rolling, no normalizing, acid pickling, cold rolling, annealing, coating and the like, and further comprising a coiling procedure before or after the cold rolling procedure. In the surface treatment procedure, the intermediate slab enters a tunnel furnace to be subjected to high-temperature reduction heat treatment in a reducing atmosphere of 90％H2+10％H2S, the temperature is maintained at 950-1000℃, and the temperature is maintained for15-30 min; and a single-layer non-oriented silicon steel finished product having a thickness of 0.15-0.30 mm is manufactured without normalizing.

The invention relates to the technical field of coal gangue resource utilization, in particular to a magnetic coal series kaolin hydrogel adsorbing material as well as a preparation method and application thereof. The preparation method of the material specifically comprises the following steps: carrying out ultrafine grinding, sieving and grading on coal gangue ore to obtain a coal series kaolinite material; further performing magnetic separation to obtain coal series kaolinite iron-rich tailings; further performing magnetizing roasting in a reducing atmosphere to obtain magnetic coal series kaolin; the preparation method comprises the following steps: compounding magnetic coal series kaolin with sodium alginate and chitosan by adopting a gel coating method, dropwise adding a calcium chloride solution for crosslinking, and freeze-drying to obtain the magnetic coal series kaolin hydrogel material. The preparation method is simple, and the obtained adsorption material has the characteristics of low cost, large adsorption capacity, high adsorption rate, high selectivity, excellent cyclic utilization performance and the like.

The present invention relates to a method of producing a catalyst structure comprising molybdenum carbide on a porous carrier compound, comprising preparing a mixture comprising a porous carrier compound and a molybdenum oxide; shaping the mixture into a porous green body by a 3D-printing technique; and carburizing the porous green body by exposing the mixture to a reducing atmosphere comprising a carbon-comprising gas at a temperature between 650 °C and 1000 °C, thereby converting at least a portion of the molybdenum oxide into molybdenum carbides and obtaining a catalyst structure having an elevated temperature; cooling the catalyst structure having an elevated temperature to room temperature in an atmosphere which is inert with respect to molybdenum oxide, thereby obtaining the catalyst structure; wherein the concentration of molybdenum oxide in the mixture is such that a ratio of the molybdenum content in the mixture to the BET surface area of the porous carrier compound in the mixture is equal to or lower than 2.5 * 10-5 molMo / m², wherein the molybdenum content in the mixture is measured by ICP-OES and the BET surface area is measured by multi-point BET analysis of a N2 adsorption isotherm. The invention further relates to a catalyst structure obtained by the methods of the invention.

The invention belongs to the technical field of catalysts, and discloses an ammonia decomposition hydrogen production catalyst and a preparation method and application thereof. The preparation method of the catalyst for hydrogen production through ammonia decomposition comprises the following steps: in an inert atmosphere, successively carrying out calcination and acid treatment on a carbon carrier to prepare an acid-treated graphitized carbon carrier; adding a ruthenium precursor, a rare earth element precursor and an alkali metal precursor into ethanol, and mixing to prepare a mixed solution; then adding a graphitized carbon carrier into the mixed solution, and mixing; then adding urea and a surfactant, continuously mixing, and standing to obtain a solid precipitate; and finally, carrying out heat treatment on the solid precipitate in a reducing atmosphere. The catalyst takes a highly graphitized carbon material as a carrier, an alkali metal is doped to provide an alkaline environment, and a rare earth metal oxide and Ru form dual-assistant synergistic regulation of an interface, so that low-temperature high-activity ammonia decomposition hydrogen production and long-acting stable operation are realized.

The invention provides a preparation method of spherical iridium powder, and relates to the field of iridium powder preparation. The method comprises the following steps: mixing an iridium raw material and an alkaline reagent to obtain a mixture, and performing first roasting on the mixture to obtain a roasted product; pickling the roasted product to obtain a pickled product; under the mixed atmosphere of argon and hydrogen, plasma spheroidizing is conducted on the product obtained after acid pickling, and a plasma spheroidized product is obtained; the plasma spheroidized product is subjected to atomization treatment, and an atomized product is obtained; the atomized product is subjected to multi-stage cooling, and cooled iridium powder is obtained; and grading the cooled iridium powder, performing secondary roasting in a reducing atmosphere, and cooling to obtain the spherical iridium powder. The spherical iridium powder is uniform in particle size and high in sphericity degree, and the compactness and stability of the spherical iridium powder are improved.

The invention relates to an electrode with an adjustable component structure and a preparation method and application thereof. The method comprises the following steps: mixing and ball-milling high-catalysis powder and active corrosion powder to obtain mixed powder; the high catalytic powder is one or more of Ni powder, Fe powder, Co powder and Mo powder, and the active corrosion powder is one or more of Al powder, Zn powder and Mg powder; depositing the mixed powder on the surface of a pretreated substrate by utilizing a directional energy deposition process to obtain a deposited electrode; carrying out heat treatment on the deposition electrode in an inert atmosphere and / or a reducing atmosphere to obtain a heat treatment electrode; and performing electrochemical corrosion on the heat treatment electrode by taking alkali liquor as electrolyte to prepare the electrode with an adjustable component structure. According to the method, additive manufacturing (directional energy deposition) and subtractive manufacturing (electrochemical corrosion) are combined, the components and the microstructure of the prepared electrode can be accurately regulated and controlled, and the prepared electrode is excellent in catalytic hydrogen evolution performance.

The invention discloses a method for separating valuable metal in a waste photovoltaic welding strip through reduction smelting-vacuum gasification-vulcanization, and belongs to the technical field of resource recycling. The method comprises the steps that the waste photovoltaic welding strip is placed in a reducing atmosphere and heated for reduction smelting, so that carbon impurities on the surface of the waste photovoltaic welding strip are removed, tin, lead, silver and copper oxides on the surface are reduced, and a copper-tin-lead-silver alloy is obtained; then, heating the decarbonized and deoxidized photovoltaic welding strip under a vacuum condition, and carrying out vacuum gasification separation to obtain condensed metal lead and a copper-tin-silver alloy; and finally, sulfur is added into the copper-tin-silver alloy for vacuum vulcanization-separation, and volatile matter stannous sulfide and residual copper-silver alloy are obtained. According to the method, valuable metals in the waste photovoltaic solder strip can be efficiently separated, and the method has the advantages of being green and economical.

The invention belongs to the technical field of solid waste resource utilization, and particularly relates to a process suitable for roasting activation of coal gangue. The process comprises the following steps: crushing and screening coal gangue to obtain a raw material; preheating at the temperature of 200-750 DEG C to extract volatile components; an inert or micro-reducing atmosphere is introduced at the temperature of 400-600 DEG C for phase control treatment; roasting and activating at 900-1200 DEG C in a mixed atmosphere of nitrogen, carbon dioxide and water vapor in a segmented heating manner; after roasting, slowly cooling and stabilizing in an atmosphere containing CO2 and water vapor; and finally, alkali leaching is adopted for desilicication, so that the aluminum-silicon ratio of the coal gangue is increased to 4-8. Through the process, local overburning and unfavorable crystal phase transformation can be effectively avoided, excessive generation of mullite is inhibited, and the separation state of aluminum oxide and silicon dioxide is kept, so that the desilicication efficiency and the dissolution rate of aluminum oxide are remarkably improved, and a feasible path is provided for efficient utilization of coal gangue resources.

A curing roasting-water leaching-normal pressure acid leaching treatment method for a lateritic nickel ore, relating to the technical field of metal smelting. The treatment method comprises the following steps: uniformly mixing lateritic nickel ore dry powder, concentrated sulfuric acid and sodium fluoride, and then carrying out curing roasting in a reducing atmosphere to obtain a cured material; carrying out water leaching on the cured material, and filtering to obtain a water leaching solution and water leaching residues; and carrying out normal-pressure acid leaching on the water leaching residues, and filtering to obtain an acid leaching solution and acid leaching residues. The treatment method has the characteristics of controllable reaction, short reaction period, low reaction energy consumption and relatively low production cost; and compared with a conventional high-pressure acid leaching treatment process, the treatment method can significantly reduce the acid consumption, reduce the loss of valuable metals such as cobalt and nickel, increase the metal recovery rate and improve the economic benefit of production. The treatment method can reduce the corrosion of a strong oxidant to equipment, reduce the emission of a waste liquid in the leaching process and reduce the production cost while effectively guaranteeing the cobalt-nickel leaching rate.

The invention relates to the technical field of catalysis, in particular to a Ru / WO3-x heterojunction catalyst, the chemical formula of the catalyst is Ru / WO3-x, and x represents oxygen vacancy; ru is loaded on the surface of a WO3-x support in the form of a metal simple substance, and the preparation method comprises the following steps: by taking tungstate as a tungsten source, ammonium sulfate as a morphology adjuvant and ruthenium trichloride as a ruthenium source, adjusting the pH value to 0-2, adding deionized water to prepare a hydrothermal reaction solution, performing hydrothermal reaction with a current collector, washing with deionized water, and drying, thereby obtaining the WO3-x support. And calcining in a reducing gas atmosphere to obtain the Ru / WO3-x heterojunction catalyst integrated electrode. Under the same test condition, nitrate can be effectively inhibited from being excessively hydrogenated into the final product ammonia, so that the product stays in the intermediate hydroxylamine.

The present invention discloses a gas low-nitrogen burner and a combustion method that couples barrier wind with staged combustion. Through the three-dimensional arrangement of gas, air and barrier wind nozzles, air, gas and 20% to 25% of recycled flue gas are evenly divided into three stages as barrier wind and delivered into the furnace. The barrier wind can delay the direct contact between air and gas, so that the gas is fully mixed with the air before ignition and is evenly diluted by the barrier wind, thereby achieving uniform combustion and uniform temperature field in the space. At the same time, the barrier wind can also reduce the oxygen partial pressure, absorb the released heat, and reduce local high-temperature areas; in addition, through the three-dimensional arrangement of gas and air and the reasonable step-by-step distribution of gas and air into the furnace, the high-temperature combustion area is controlled to create a reducing atmosphere, even in the presence of NO x The present invention couples the barrier wind and staged combustion technology to reduce the NO x The emission concentration is reduced to less than 30mg / Nm 3 It is suitable for newly built or existing low-nitrogen gas boiler projects and has broad application prospects.

The invention provides a method for preparing ferrous sulfate from iron-containing solid waste, and relates to the field of solid waste treatment. The method for preparing ferrous sulfate from the iron-containing solid waste comprises the following steps: mixing concentrated sulfuric acid and the iron-containing solid waste, and curing in a reducing atmosphere or a protective atmosphere to obtain a cured material; the cured material is subjected to water leaching and centrifugal separation, and silicon-containing slag and leachate are obtained; carrying out deepening treatment on the silicon-containing slag to obtain white carbon black; the leachate and iron powder are mixed for a reduction reaction, then a vulcanizing agent is added for vulcanization, precipitation and impurity removal, and copper sulfide slag and a ferrous sulfate solution are obtained through solid-liquid separation; treating the copper sulfide slag to recover valuable metals; and crystallizing the ferrous sulfate solution to obtain ferrous sulfate crystals. According to the method for preparing the ferrous sulfate from the iron-containing solid waste, low-cost, short-process and high-efficiency treatment of the iron-containing solid waste is achieved, and the ferrous sulfate product is obtained.

The invention discloses a method for inhibiting abnormal expansion of ultrahigh-grade pellets through gradient heating reduction of a hydrogen-based shaft furnace, and belongs to the technical field of direct reduction iron production. The method comprises the following steps: continuously adding ultrahigh-grade pellets from the top of a hydrogen-based shaft furnace, and sequentially passing through a first heating reduction zone (the heating speed is 10-20 DEG C / min, and the temperature reaches 900-930 DEG C), a second heating reduction zone (the heating speed is not less than 30 DEG C / min, and the temperature reaches 990-1020 DEG C), a constant-temperature reduction zone and a cooling zone of the hydrogen-based shaft furnace to obtain the direct reduction iron. The method is suitable for the hydrogen-based shaft furnace with various reducing atmospheres, the maximum reduction expansion rate of the ultrahigh-grade pellets in the reduction process of the hydrogen-based shaft furnace can be smaller than 15% on the premise that the original iron grade of the pellets is not reduced, high-purity direct reduction iron with qualified production indexes is produced, and reduction of follow-up electric furnace smelting energy consumption and the molten iron refining process are facilitated.

The invention discloses a layered, zoned and differentiated CO2 injection system and method for a blast furnace, and belongs to the technical field of ferrous metallurgy low carbon. The system comprises a CO2 supply and distribution system, a tuyere area injection module, a furnace body middle-lower part injection module and a furnace body upper part injection module. And according to the temperature gradient and atmosphere layering characteristics in the blast furnace, a differential CO2 distribution proportion and a collaborative thermal compensation strategy are adopted. An oxygen-CH4 synergistic injection device is arranged in a tuyere area, and rapid conversion of CO2 is promoted by using a high-temperature strong reducing atmosphere; a biomass charcoal synergistic injection device and an angle-adjustable nozzle are arranged at the middle lower part of the furnace body, so that efficient gasification reaction is realized; and low-concentration CO2 mixed injection is adopted at the upper part of the furnace body, so that indirect reduction reaction is promoted. According to the invention, the CO2 conversion rate is 65-80%, the coke ratio is reduced by 15-25%, the consumption of CO2 per ton of iron is 260-90Nm < 3 >, the carbon emission is obviously reduced, and the ironmaking efficiency is improved.

A molecular sieve catalytic slag melting agent for high-iron coal liquid slag removal comprises 10-20 parts of a loosening and expanding agent, 10-20 parts of a molecular sieve catalyst and 30-60 parts of a fluxing reducing agent, and has the beneficial effects that the loosening and expanding agent can crack and expand ash; vanadium anhydride added in the fluxing reducing agent can promote generation of low-temperature eutectic substances in the ash residues when the mass fraction is lower than 5%. And further, under the action of the molecular sieve catalyst enhanced reaction, the fluxing reducing agent can enhance the reducing atmosphere, promote the conversion of ferric iron in the slag body to ferrous iron, reduce the melting point of an iron-containing compound, promote the conversion of the solid slag body at the slag discharge port to low-melting-point liquid-phase flow slag, and ensure that ash in the furnace is smoothly discharged out of the furnace body. Through reasonable preparation, the slag melting agent developed by the invention can realize fluidization of slag at a slag discharge port within a temperature range of 900 DEG C, avoids unplanned furnace shutdown or safety problems caused by slag blockage, and also can realize the effect of replacing the existing natural gas heating fluxing anti-slag-blocking technology.