50 results about "Oxidation process" patented technology

The invention discloses a numerical calculation method for simulating combustion of iron powder group particles, belongs to the field of numerical simulation calculation of iron powder combustion, can perform numerical simulation on single-particle and iron powder group combustion under a microgravity condition, quantitatively analyzes the influence of differential diffusion on single-particle iron powder and iron powder group combustion flame temperature, and improves the calculation accuracy of the single-particle and iron powder group combustion flame temperature. And meanwhile, the influence of iron powder combustion characteristics and flame propagation speeds under different iron powder and oxygen concentration conditions is considered. The method has a certain guiding significance in research on low-propagation-speed lean-burn iron powder flames and subsequent application of iron powder fuel. The microgravity environment can eliminate the influence of convection and buoyancy, so that the combustion process is more stable and predictable, and the basic mechanisms of iron powder combustion, including combustion rate, oxidation process, phase change and the like, can be deeply researched.

The invention relates to the technical field of non-ferrous metal metallurgy, in particular to a comprehensive recovery method for low-grade lead-zinc oxidized ore resources. According to the method, through a side-blown smelting furnace oxidation process and a fuming furnace reduction process, firstly, pyrometallurgy oxygen-enriched smelting is carried out, high-lead smoke dust and zinc-germanium-containing slag are produced, zinc oxide smoke dust is obtained through fuming reduction volatilization, then the zinc oxide smoke dust enters a zinc hydrometallurgy process, the high-lead smoke dust enters a pyrometallurgy lead smelting process for batching, and the zinc-germanium-containing slag is obtained. And finally, lead metal (rich in silver), zinc metal, germanium concentrate and tailings are generated. The method aims at achieving comprehensive recovery of low-grade lead-zinc oxidized ore resources by improving the recovery rate of lead and zinc in the low-grade lead-zinc oxidized ore and conducting cooperative treatment on silver, germanium and cadmium at the same time, and a new thought is provided for comprehensive recovery and large-scale industrial production of the low-grade lead-zinc oxidized ore resources.

The application discloses a method for repairing chlorinated groundwater pollution based on carbon dioxide nanobubbles, and the method is characterized in that nZVI, H2O2 and EDDS reagents are injected in a time sequence at different stages, and CO2 nanobubbles are used as a multifunctional medium throughout the process. The CO2 nanobubbles not only continuously remove the passivation layer through in-situ acidification, thereby fundamentally promoting the reduction effect of nZVI on chlorinated organic matter, but also couple a subsequent Fenton oxidation process, thereby greatly promoting the complete oxidation effect of toxic intermediates, effectively inhibiting the conversion of the final reaction product Fe 2+ Into secondary minerals, and controlling the risk of blockage from the source. Through the design of in-situ generation of catalyst Fe 2+ And the final removal of iron ions, the application maximizes the dosage of exogenous chemicals and the final residual, overcomes the environmental risks that may be introduced by traditional technologies or cause permanent physical damage, and realizes efficient, complete and sustainable repair of chlorinated organic pollutants in groundwater. 3+ ​

The invention relates to the technical field of high-pigment carbon black, in particular to a production method and application of medium-high-pigment carbon black. Raw oil, air and natural gas are introduced into the carbon black reaction furnace for secondary combustion; quenching for four times at the outlet of the reaction furnace after combustion; and arranging a main bag filter at an outlet of the reaction furnace to collect carbon black, and granulating by using a dry granulator to obtain the medium-high pigment carbon black. By optimizing the carbon black production process, on the premise of not using strong acid oxidation, the oxygen-containing functional group can be efficiently introduced on the surface of the carbon black only by accurately regulating and controlling the air inlet amount, the reaction temperature and the retention time. According to the method, the problems of pH imbalance and activity reduction caused by traditional acid treatment are avoided, the surface polarity of the carbon black can be remarkably enhanced, meanwhile, a low pH value of 6-7 and high surface activity are kept, the iodine absorption value is increased, the coloring power is enhanced, and the contradiction of activity loss and performance reduction existing in a traditional oxidation process is effectively solved.

Disclosed is methodology for controlling the H2:CO ratio of the product produced in a partial oxidation reactor, by adjusting the properties of the product formed in the partial oxidation.

The invention relates to a magnetic water supply sludge catalytic material and a preparation method thereof.The preparation method comprises the steps that water supply sludge, cement, water glass and sodium bicarbonate are mixed according to a first proportion on the basis of the ultrasonic condition, and a first sample is obtained; drying, granulating and carbonizing the first sample to obtain a second sample; mixing the second sample with an iron-containing compound to obtain a third sample, and performing reduction reaction and washing on the third sample to obtain the magnetic water supply sludge catalytic material. According to the scheme provided by the invention, waste utilization of the sludge can be realized, the recycling rate of the sludge is increased, and the nano-scale magnetite on the surface of the generated material has a high specific surface area and can provide a catalytic action for a subsequent oxidation process of water treatment.

The invention belongs to the field of metal object oxidation data judgment methods in the electroplating process, and particularly relates to an information judgment method in the metal object oxidation process in the electroplating process. The method comprises the steps of firstly collecting oxidation process information and identifying an oxidation abnormity type; then selecting a key reference index, and obtaining feature data; and arranging the data by using the performance index matrix, and carrying out normalization processing through a minimum-maximum standardization method. And further setting a standard performance index matrix, and calculating the cosine similarity between the target matrix and the standard matrix to identify the oxidation anomaly. Through systematic data analysis, automatic monitoring of the oxidation process is achieved, and the production efficiency and the reliability of metal objects in the electroplating process are improved.

The application provides a method for efficiently recycling valuable elements by synergistically smelting neodymium iron boron waste and electronic waste, which comprises the following steps: preparing a mixture of powdered neodymium iron boron waste, fine-grained electronic waste, a slagging agent and a solid reducing agent; and using a top-blown smelting furnace to oxidize and reduce the mixture; by controlling the conditions of the oxidation process, the iron and rare earth in the mixture are oxidized into oxides and enter the slag, copper is not oxidized and captures rare and precious metals such as gold and silver to form crude copper and sink to the bottom of the furnace and is discharged; by controlling the conditions of the reduction process, the iron oxide in the mixed rare earth slag is reduced to metallic iron, and the rare earth oxide is not reduced and remains in the slag layer; the iron with a larger density than the rare earth slag sinks to the bottom of the furnace, and after static stratification, the iron and the rare earth slag are discharged from the metal outlet and the slag outlet respectively, so that the separation of the rare earth and the iron is realized; and finally, the synchronous recovery of the rare earth, the iron in the neodymium iron boron waste and the copper, gold and silver in the electronic waste is realized; the method has a short process flow, low energy consumption and good economic and environmental benefits.

The invention discloses an in-situ curing method for heavy metals in entrained-flow bed coal gasification fine slag based on potassium permanganate oxidation, and belongs to the technical field of harmless treatment of solid wastes. According to the method, the reducibility of residual carbon in the fine slag is utilized, the residual carbon and potassium permanganate (KMnO4) are subjected to an oxidation-reduction reaction, a reducing agent does not need to be additionally added, and multivalent manganese oxide with heavy metal fixing capacity is generated on the surface of the fine slag in situ. The generated manganese oxide can be loaded on stable silicon-aluminum glass microspheres in fine slag to form a stable composite structure. Meanwhile, a large number of functional groups such as carboxyl are introduced into the carbon component in the oxidation process, the aroma degree of the carbon structure is improved, and the complexing ability on heavy metal ions and the cation-pi effect are effectively improved. Manganese oxide and a carbon component have a synergistic effect, so that the weak acid extraction state content of heavy metal in the fine slag is remarkably reduced, and the environmental migration risk is remarkably reduced. The method is mild in process and simple and convenient to operate, and provides a new technical path and support for innocent treatment of the coal gasification fine slag.

This invention discloses a method for oxidative leaching of selenium and mercury from copper smelting acid sludge, belonging to the field of solid waste comprehensive utilization technology. The leaching system in the oxidative leaching is a ternary synergistic oxidative leaching system of "sulfuric acid-sodium chloride-oxidant". Under the action of the synergistic leaching system, efficient and selective leaching of selenium and mercury from copper smelting acid sludge is achieved. This method avoids the corrosion of equipment by volatile acids and the problem of excessive oxidation of the nitric acid system, and significantly improves the stability of the oxidation process and the efficiency of reagent utilization, ultimately achieving multiple goals such as efficient recovery of valuable metals, low-carbon and energy-saving process flow, and compliant and harmless treatment of hazardous waste.

A precious metal leaching method includes providing a slurried feed, comprising (i) in the solid phase, a refractory sulfide-containing material, the material comprising at least about 0.05 oz / tonne of a precious metal, at least about 0.75 wt. % sulfides, optionally at least about 0.1 wt. % feldspar (i.e., muscovite), and at least 0.3 wt. % preg-robbing carbonaceous material; and oxidizing the sulfide-containing material at more than about 240° C. and super-atmospheric pressure to oxidize at least most of the carbonaceous material and optionally convert at least most of the sulfide sulfur to sulfate sulfur and form an oxidized precious metal-containing material, wherein at least one of the following is performed during oxidizing: maintaining a pH of at least about pH 1.5; maintaining at least about 98.5% of the feldspar (i.e., muscovite) in the solid phase; maintaining a dissolved cupric ion concentration of at least about 0.25 g / L; and maintaining the slurried feed under subcritical or supercritical water operating conditions.

The application discloses a kind of high oxidation process catalysts for low-cost treatment of industrial organic wastewater and its preparation method and application, belong to environmental remediation material preparation and water pollution control field.The preparation of the catalyst is based on biochar, natural iron manganese mineral, first, after screening, natural magnetite and soft manganese ore are fully mixed in a certain proportion and are subjected to ball milling treatment, and the biochar doped with impurity elements is obtained by pyrolysis method, the impurity element doped biochar, iron manganese mineral composite catalyst is fully mixed, and then ball milling treatment is carried out under the protection of inert atmosphere, and the catalyst is obtained.The impurity element doped biochar contained in the catalyst promotes the aggregation of pollutants and electron transfer, and the iron manganese bimetallic elements can be used as active sites, and the synergistic effect between them significantly increases the activation efficiency and improves the degradation efficiency of pollutants.

The application discloses a method for reducing lime consumption in smelting stainless steel from ferro-nickel water, and belongs to the technical field of stainless steel smelting. The method mainly comprises nine steps of iron adding, desiliconizing period, main decarburization period, secondary decarburization period, side gun decarburization first stage, side gun decarburization second stage, side gun decarburization third stage, reduction stage and adjustment stage. The method can significantly reduce lime consumption, indirectly reduce ferrosilicon and fluorite consumption, and reduce production cost by stabilizing the alkalinity and silicon content in the desiliconizing period, improving the carbon content at the end of the main decarburization period and the secondary decarburization period, and reducing the oxygen supply intensity in the secondary decarburization period and the oxidation of Cr elements in the oxidation process.

The invention relates to the field of iron phosphate production, and discloses a method and a system for preparing iron phosphate by continuous feeding, and the method is characterized in that reaction kettles are connected in series, and continuous feeding is performed at different points to realize continuous oxidation of iron-process iron phosphate. Firstly, a certain amount of ferrous liquid is supplemented into the first reaction kettle to serve as a reaction base solution, a PH buffer system is provided for the whole reaction, and the whole continuous feeding oxidation process is more controllable. By adjusting the parameters such as the feeding speed, the feeding proportion of each point, the temperature and the like in the oxidation process, the particle size-controllable iron phosphate dihydrate slurry in which coarse and fine particles are mixed can be obtained, so that the particle size distribution, the specific surface and Fe / P of an iron phosphate product are easy to regulate and control.

The application discloses a copper rod smelting anti-oxidation process and belongs to the technical field of copper rod smelting, which comprises the following steps: step one, pretreatment; step two, adding an anti-oxidation agent; step three, adopting an oxidation-reduction reaction; step four, stirring copper liquor; step five, filtering the copper liquor; step six, preventing hot air from being introduced; step seven, controlling the oxygen content of a smelting furnace; step eight, controlling the smelting temperature; step nine, controlling the smelting time; step ten, accelerating the smelting speed; and step eleven, discharging and cooling. The copper rod smelting anti-oxidation process can remove other substances mixed in the smelted copper rod, reduce the viscosity of the copper liquor in the smelting process, reduce the resistance and energy consumption in the smelting furnace, reduce the chance of impurities contacting air and the possibility of oxidation, filter out large-particle impurities, reduce the viscosity of the copper liquor, help to improve the fluidity of the copper liquor and thus reduce the possibility of oxidation.

The invention discloses a method for measuring low-temperature oxidation reaction rate of crude oil by using pressure changes under different atmosphere conditions, and belongs to the technical field of oil reservoir development. According to the technical scheme, a pressure-bearing container is adopted, and an air and high-purity nitrogen parallel contrast experiment is designed, so that the oxidation process of crude oil at low temperature is accurately quantified; the interference of nitrogen on oxygen consumption evaluation is effectively eliminated by accurately monitoring and comparing the change of pressure in the two containers along with time, so that the oxidation reaction of oxygen and crude oil is accurately reflected; and calculating the oxidation reaction rate in combination with a gas state equation. The method has the beneficial effects that the data accuracy can be remarkably improved, the oxidation characteristics of the crude oil can be quickly evaluated, and the production process and safety management are optimized; meanwhile, understanding of an oxidation mechanism is deepened, and development of a kinetic model is promoted. The method is widely applicable to evaluation of oxidation stability of chemicals in the fields of energy, chemical industry and the like, and industrial green transformation and technical innovation are promoted.

The present invention discloses a numerical calculation method for simulating the combustion of iron powder group particles, which belongs to the field of numerical simulation calculation of iron powder combustion. The present invention can perform numerical simulation on the combustion of single particles and iron powder groups under microgravity conditions, quantitatively analyze the influence of differential diffusion on the flame temperature of single iron powder particles and iron powder groups, and consider the influence of iron powder combustion characteristics and flame propagation speed under different iron powder and oxygen concentration conditions. The invention has certain guiding significance for the study of lean-burn iron powder flames with low propagation speeds and the subsequent application of iron powder fuel. The microgravity environment can eliminate the influence of convection and buoyancy, making the combustion process more stable and predictable, and helping to conduct in-depth research on the basic mechanism of iron powder combustion, including combustion rate, oxidation process and phase change.

A method for extracting copper from sulphide mineral ore, comprising the following steps: stacking the ore to form a pile (heap), a leaching step, irrigating the pile with a first irrigating solution containing an acidic nitrate solution and nitrite, thereby causing the oxidation of sulfide minerals inside the pile, oxidation of gaseous nitrogen oxide released during the oxidation of sulfide minerals inside the pile with oxygen to form nitrogen dioxide, and hydrolysis of nitrogen dioxide to form nitric acid and / or nitrous acid in the first irrigating solution inside the pile, to continue the leaching stage and reduce nitrogen oxide losses from the pile.

The present invention provides an application of Aspergillus in inhibiting coal spontaneous combustion. An Aspergillus is obtained from a collected coal sample through enrichment, extraction, separation, and domestication. The domesticated Aspergillus is mixed and reacted with pulverized coal to delay the oxidation process of pulverized coal spontaneous combustion, delay the spontaneous combustion characteristic temperature point of pulverized coal, and inhibit the spontaneous combustion of pulverized coal. The method for mixing and reacting the domesticated Aspergillus with pulverized coal is as follows: inoculate the domesticated Aspergillus into a modified inorganic salt medium, then place it in the sterilized pulverized coal and react under oscillation at a temperature of 28-30 °C for 12-15 days. Wash, filter by suction, and dry the reacted pulverized coal to obtain the treated coal sample. The Aspergillus before domestication is obtained from the collected coal sample through enrichment, extraction, and separation. In the present invention, the treated coal sample obtained by treating the coal sample with the domesticated Aspergillus can effectively delay the oxidation process of coal spontaneous combustion, delay the spontaneous combustion characteristic temperature point of coal, reduce the heat release of coal, and inhibit the occurrence of coal spontaneous combustion fires.

The application discloses a kind of pressure control condition under the oxidation testing device of coal body around borehole, including test tank body, gas supply device is arranged at the bottom of test tank body, gas detection device is arranged at the top of test tank body, the porous supporting plate is fixedly connected at the bottom of test tank body, the porous top plate is fixedly connected at the top of test tank body, heat shrink tube is arranged between porous top plate and porous supporting plate, coal sample is arranged in heat shrink tube, pressure cavity is formed between the outer wall of heat shrink tube and the inner wall of test tank body, the sliding groove is arranged in porous top plate, the sliding block is slidably connected in sliding groove, the drill rod is rotatably connected to sliding block, the drill sleeve is fixedly connected to the lower end of drill rod, the pre-charged inflatable rubber membrane elastic pipe column is arranged outside drill rod, and the lancet is fixedly connected to sliding block. On the one hand, the pipe column is broken and shrinks, the internal pore of coal sample collapses, the effect of borehole surrounding coal body breaking under the action of simulated test pressure is simulated, and the test working condition is consistent with the actual situation. On the other hand, the application can simulate the actual coal oxidation process under different gas environments.

The present application belongs to the field of preparation of cracking furnace tube, and particularly relates to an anti-coking furnace tube with an oxidation layer with good high-temperature stability and a preparation method thereof. The present application generates a complete and dense, single and uniformly distributed Al2O3 oxidation layer on the surface of the furnace tube by optimizing the alloy composition and adopting a two-step low-temperature and high-temperature pre-oxidation process, i.e. after low-temperature heat treatment of the furnace tube in a low-oxygen partial pressure atmosphere, the furnace tube is heated to high temperature at a constant heating rate for heat treatment, and the oxidation layer can exhibit excellent high-temperature stability and adhesion during high-temperature cyclic oxidation at 1000 DEG C for 460 h.

The present application relates to a kind of phosphogypsum method and system of sulfuric acid.The method includes the following steps: (a) phosphogypsum and reducing agent are mixed granulation, and raw material particle is obtained;(b) raw material particle is treated by reduction, and after reduction material is obtained, after reduction material is treated by oxidation, and calcium oxide and flue gas are obtained;(c) flue gas is carried out gas-solid separation, after heat exchange of gas phase and oxygen-containing gas, preheated oxygen-containing gas and heat exchanged flue gas are obtained;(d) after heat exchanged flue gas is treated by impurity removal, sulfur dioxide in converted impurity-removed flue gas is converted into sulfur trioxide, and converted flue gas is obtained;(e) converted flue gas is absorbed by sulfuric acid with mass fraction of more than 98%, and sulfuric acid product and absorption tail gas are obtained;Wherein, preheated oxygen-containing gas is divided into two, and is respectively introduced into reduction process and oxidation process.The method of the present application can greatly reduce production cost, improve calcium sulfate decomposition rate, improve flue gas sulfur dioxide concentration and product quality.

The invention belongs to the technical field of preparation of iron oxide red, and discloses a preparation method of high-purity iron oxide red, which comprises the following specific steps: step 1, preparing a refined ferrous iron source solution, and accurately weighing industrial-grade ferrous sulfate heptahydrate (FeSO4. 7H2O) crystals; a low-defect alpha-FeC2O4 precursor is constructed by utilizing a hydrothermal crystallization technology, so that the risk that impurity ions are introduced in traditional acid pickling is fundamentally avoided, meanwhile, self-purification of the precursor is realized, the oxidation process at the initial stage of calcination is accurately controlled through a nitrogen and carbon dioxide mixed atmosphere, lattice distortion is effectively inhibited, and the preparation method is simple and convenient to operate. Lattice oxygen dynamic reconstruction is achieved through oxygen-argon alternate treatment, surface hydroxyl adsorption is thoroughly eliminated, the thermal stability and weather resistance of the product are greatly enhanced, supercritical CO2 flow state purification is adopted to replace water washing, residual impurities are efficiently removed, meanwhile, the risks of powder agglomeration and secondary pollution are avoided, and the method is suitable for industrial production. And high fluidity and excellent dispersibility of the product are ensured.

The application discloses a COD degradation treatment method and system for industrial wastewater, and relates to the field of wastewater treatment, which comprises the following steps: introducing the industrial wastewater into a micro-electrolysis unit, monitoring water quality parameters in real time, dynamically setting the pH value of the micro-electrolysis unit according to the water quality parameters and a preset optimization algorithm model, and obtaining pretreated effluent; introducing the pretreated effluent into a heterogeneous Fenton treatment unit, adding hydrogen peroxide and a heterogeneous Fenton catalyst composed of iron and carbon to the pretreated effluent, dynamically controlling the oxidation process based on real-time monitoring data, and obtaining oxidized effluent; adding reagents to the oxidized effluent, intelligently controlling the flocculation and sludge discharge process based on real-time monitoring data, realizing solid-liquid separation, and obtaining purified effluent. By combining micro-electrolysis treatment with heterogeneous Fenton treatment, the working efficiency and quality of the degradation treatment of industrial wastewater are improved, and a large amount of hazardous waste iron sludge is reduced, thereby reducing the secondary pollution risk of industrial wastewater treatment.

The invention discloses a method for reducing consumption of lime for smelting stainless steel by using molten nickel iron through AOD (argon oxygen decarburization), and belongs to the technical field of stainless steel smelting. The method mainly comprises nine steps of iron adding, a desilicication period, a main decarburization period, a secondary decarburization period, a first stage of side gun decarburization, a second stage of side gun decarburization, a third stage of side gun decarburization, a reduction stage and an adjustment stage. The oxygen supply intensity in the secondary decarburization period is reduced, oxidation of the Cr element in the oxidation process is reduced, lime consumption can be remarkably reduced, consumption of silicon iron and fluorite is indirectly reduced, and the production cost is reduced.

The invention provides a method for calculating the oxidation rates of S, As and Fe in a biological oxidation process, and belongs to the technical field of process mineralogy. According to the method, MLA is introduced to detect the change of the relative content of minerals before and after biological oxidation of the gold concentrate, the oxidation rate of the biological oxidation process is measured, and the technical problem that toxic and harmful gas can be generated when iron, sulfur and arsenic phases are detected through a traditional acid-base chemical leaching method is solved; by pretreating the oxidizing slag, the influence of an oxidation film on the outer ring of sulfide in the oxidizing slag is eliminated, and the measurement error of the relative content of the sulfide is reduced; according to the method, the correction coefficient is introduced for measurement and calculation, and measurement and calculation errors caused by irregular shapes and too small particle sizes of mineral particles are reduced, so that the real mass closer to the reality is obtained, and the measured mineral content is more accurate. Compared with a traditional method, the method is easy to operate, simple and convenient in process, accurate in data and high in timeliness.

This invention discloses a modular, controllable atmosphere high-temperature oxidation device for the recovery of substandard sponge zirconium, relating to the fields of nuclear fuel cycle and materials technology. The device includes: a furnace body system, comprising, from the outside to the inside, a steel outer shell, a refractory insulation layer, and a detachable furnace liner; multiple independently controlled heating zones arranged along the furnace body axis, each equipped with an independent heating element and thermocouple; an atmosphere control system including nitrogen and oxygen sources, an inert gas source, a mass flow controller, and a mixer; a sealing and cooling system employing a high-temperature sealing ring and a double-layer furnace shell design, with circulating cooling water flowing through the interlayer; and an automatic control system equipped with a temperature-atmosphere-time automated control program for fully automated operation and remote monitoring of the oxidation process. The device provided by this invention can achieve efficient and uniform oxidation treatment of irregular porous sponge zirconium within the range of 500-1000℃, transforming it into zirconium oxide with consistent physical properties.

The invention discloses a coal flame retardant based on calcium salt substances, which consists of the following components in percentage by weight: 50-90% of a main flame retardant which is one or more calcium salt substances; 5%-30% of a catalytic synergist which is a metal oxide or hydroxide; the surfactant is used for improving the wettability and adhesiveness of the flame retardant on the surface of coal; and the balance of a filler. According to the coal flame retardant based on the calcium salt substances, the characteristic that calcium salt (such as calcium carbonate and calcium hydroxide) is decomposed and releases carbon dioxide and water when heated is utilized, the oxygen concentration on the surface of coal can be effectively reduced, a large amount of heat is absorbed, and therefore the oxidation process of coal is efficiently inhibited from the two aspects of the gaseous state and the heat source.

The invention provides a deep trench isolation structure and a manufacturing method thereof, and the method comprises the steps: providing a substrate, and forming a deep trench in the substrate; a first oxidation process and a second oxidation process are sequentially executed, a first oxidation layer and a second oxidation layer are sequentially formed on the side wall and the bottom of the deep trench, the first oxidation process is oxidation in the atmosphere of chlorine-containing gas, and the second oxidation process is wet oxidation; executing a high-density plasma chemical vapor deposition process, and forming a third oxide layer on the side wall and the bottom of the deep trench; and filling polycrystalline silicon in the deep trench. According to the invention, through the combination of the two oxidation processes and the chemical vapor deposition process, under the condition of not changing the film thickness of the traditional oxidation layer, an outward concave sharp corner which is easy to appear after the oxidation layer is grown at the bottom of the deep trench in the traditional process can be eliminated, so that filling material cracks caused by stress accumulation during filling of polycrystalline silicon are reduced, and the quality of the polycrystalline silicon is improved. And meanwhile, the process compatibility is improved, and the performance and the reliability of the device are improved.

The invention discloses a method for multi-stage remediation of chlorine-containing groundwater pollution based on carbon dioxide nanobubbles, nZVI, H2O2 and EDDS reagents are injected in different stages in a sequential manner, the CO2 nanobubbles are used as a multifunctional mediator penetrating through all the time, the CO2 nanobubbles continuously remove a passivation layer through in-situ acidification, and the CO2 nanobubbles are used for repairing the chlorine-containing groundwater pollution through in-situ acidification. According to the present invention, the reduction effect of the nZVI on the chlorine-containing organic matter is fundamentally promoted, and the by-product Fe < 2 + > of the nZVI reaction is coupled with the subsequent Fenton oxidation process, such that the complete oxidation effect on the toxic intermediate product is substantially promoted, the final reaction product Fe < 3 + > can be effectively inhibited from being converted into the secondary mineral, and the blocking risk is controlled from the source. Through the design of in-situ generation of the catalyst Fe < 2 + > and final removal of iron ions, the dosage and final residues of exogenous chemicals are reduced to the maximum extent, and the environmental risk that exogenous pollution is possibly introduced or permanent physical damage is caused in a traditional technology is overcome; the efficient, thorough and sustainable remediation of the chlorine-containing organic pollutants in the underground water is realized.