255 results about "Ferrous" patented technology

The invention provides a dump leaching method for improving the leaching rate of gold ore, and belongs to the technical field of mineral processing. The method comprises the following steps: firstly, separating minerals into oversize products and undersize products; mixing sodium carboxymethyl cellulose, bentonite and ferrous sulfate to obtain a mixture, and granulating the undersize product by using the mixture as a binder; and mixing the undersize product particles with the oversize product, and carrying out cyanide-free dump leaching. According to the method, through graded granulation and heap building, the problem that heap building permeability is poor due to the fact that the gold ore contains many clay minerals is solved. In the granulation stage, ferrous hydroxide colloid generated by hydrolysis of ferrous sulfate in the binder can assist ore particle agglomeration, and particle stability is enhanced; during subsequent cyanide-free dump leaching, ferrous sulfate can be used as an auxiliary reducing agent and a catalyst in a thiourea gold leaching system to promote oxidation and dissolution of gold; meanwhile, ferrous ions can adjust the oxidation-reduction potential of a system, so that the thiourea gold leaching reaction is in a more favorable potential interval, the oxidation efficiency of thiourea is improved, invalid decomposition of thiourea is reduced, and therefore the use amount of thiourea and the use amount of agents are reduced.

The invention discloses a production method of ferrous dihydrogen phosphate, which comprises the following steps of: changing an iron source of iron-process iron phosphate from traditional iron blocks or iron powder into oxide scale, compounding phosphoric acid and sulfuric acid into mixed acid, and controlling the granularity of the oxide scale and the components and acidity of the mixed acid to solve the problems of dissolution and passivation of the oxide scale. According to the method, iron oxide scale can be better dissolved, the residual problem of ferric ions is solved by reducing excessive iron blocks or iron powder, undissolved impurities such as carbon, silicon and iron are removed by filtering, and finally, the stability problem of a reaction system is solved by adjusting the pH value of the system through industrial phosphoric acid and pure water, so that a ferrous dihydrogen phosphate solution required for producing iron phosphate is obtained. The production cost of an iron source required by iron phosphate is greatly reduced, other impurities are not contained, and mixed acid-containing filtrate and washing water generated in the production process can be recycled through an evaporation device.

The invention discloses a preparation method of a lithium iron phosphate positive electrode material, three iron sources with different forms and different particle sizes participate in preparation of the lithium iron phosphate positive electrode material, and gradation is formed to improve the compaction density and rate capability of the material. The EDTMPA reduces the viscosity of the slurry, is anchored on the surface of FePO4 particles through strong adsorption, inhibits particle aggregation through steric hindrance and electrostatic repulsion effect, and introduces hydrophilic groups to enhance wettability, reduce the viscosity of the system, optimize dispersion stability, accelerate particle crushing and refining, reduce the particle size and shorten the grinding time; in the sintering process, a reducing agent is generated through pyrolysis to inhibit too fast oxalic acid decomposition to cooperate with the generated reducing gas, Fe < 3 + > is completely reduced, the reduction temperature is reduced to inhibit grain growth, and the grading effect between large and small particles is improved; in addition, an N-doped carbon coating layer is formed through high-temperature cracking, pores are filled with residual carbon generated through decomposition of ferrous oxalate, the coating density is improved, the carbon-coated graphitization degree is improved, and then the electronic conductivity and the rate capability of the material are improved.

The invention discloses a preparation method and application of a high-density iron-nitrogen-carbon monatomic catalyst. The method specifically comprises the following steps: S1, uniformly mixing nitrogen-doped carbon and ferrous oxalate; s2, in an inert atmosphere, carrying out a first pyrolytic reaction at 340-360 DEG C to obtain an intermediate, and meanwhile, carrying out etching on the carbon carrier by using CO2 gas generated by the reaction, so that a plurality of microporous structures are formed on the carbon carrier; s3, the intermediate continues to be subjected to a second pyrolytic reaction in the inert atmosphere at the temperature of 850-950 DEG C, the FeOx nano-particles are converted into Fe-N4 active sites, and a pyrolytic product is obtained; and S4, naturally cooling to room temperature to obtain the high-density iron-nitrogen-carbon monatomic catalyst. Superfine ferric oxide (FeOx) nano-particles are generated through a precursor to serve as intermediates, carbon defects are created through CO2 gas released in the decomposition process of the FeOx nano-particles, and therefore the oxygen reduction reaction performance of the catalyst is remarkably improved, and the catalyst is applied to fuel cells.

The invention relates to a process for preparing pure iron by using red mud, which is characterized in that the red mud is Bayer process red mud, i.e., solid waste residue formed by solid-liquid separation after aluminum oxide is dissolved out from bauxite through high temperature, high pressure and strong alkali in the process of producing aluminum oxide by adopting a Bayer process, so that the environmental burden caused by the Bayer process red mud can be solved; the method is beneficial for reducing carbon emission in the aspect of iron element extraction and promoting development of a green metallurgical technology, and is characterized by comprising the following steps: taking Bayer process red mud as a raw material, carrying out acid leaching on the Bayer process red mud to obtain a ferrous oxalate extract, calcining the ferrous oxalate to obtain iron oxide, and recycling the iron oxide. And dissolving the ferric oxide into a sulfuric acid solution to obtain a ferric sulfate solution, taking the ferric sulfate solution as an electrolyte in an electrolysis device, and obtaining electrolytic iron through the electrolysis device, so that the pure iron is prepared from the red mud.

The invention discloses a method and system for preparing iron phosphate through an iron powder method based on oxygen micro-nano bubbles and application, and belongs to the technical field of iron phosphate preparation. The method comprises the following steps: pulping iron powder and pure water, injecting the pulped iron powder and pure water into an iron dissolving reaction kettle, adding phosphoric acid, and carrying out a leaching reaction under corresponding preset conditions to obtain a first solution containing ferrous dihydrogen phosphate; after solid-liquid separation, pumping the second filtrate into an oxidation kettle, introducing oxygen micro-nano bubbles by using a micro-nano bubble generator, and carrying out oxidation reaction on the second filtrate and ferrous dihydrogen phosphate under corresponding preset conditions to obtain a third solution containing amorphous hydrated iron phosphate and phosphoric acid; pumping the third solution into an aging kettle, and aging the amorphous ferric phosphate hydrate to generate ferric phosphate dihydrate, so as to obtain a fourth solution; after solid-liquid separation, washing the iron phosphate dihydrate, and carrying out flash evaporation drying on a filter cake to obtain dry powder; and roasting and dehydrating to finally obtain the battery-grade anhydrous iron phosphate. According to the method, reaction conditions are accurately controlled, oxygen micro-nano bubbles are innovatively introduced for oxidation, and a new way is provided for preparing high-performance products.

The invention provides a method for recovering fluorine in tailings containing fluorine, tantalum and niobium. The recovery method comprises the following steps: mixing and leaching the fluorine-containing tantalum-niobium ore tailings and a sulfuric acid solution, and carrying out solid-liquid separation to obtain a leachate; mixing and reacting a reducing agent with the leaching solution to reduce iron ions in the leaching solution into ferrous ions, so as to obtain an extraction material solution; mixing the extraction feed liquid with an organic phase, carrying out extraction treatment, and carrying out phase splitting to obtain a fluorine-containing extraction liquid; the organic phase comprises trioctylamine, an additive and a diluent; and mixing the fluorine-containing extraction liquid with an alkali solution, carrying out reverse extraction treatment, and carrying out phase splitting to obtain a fluorine-containing reverse extraction liquid and a no-load organic phase.

A method for separating iron and phosphorus from an iron phosphate-based material obtainable from a waste water treatment process is disclosed. The method may comprise leaching the iron phosphate-based material with an acid; precipitating at least a part of the iron leached from the iron phosphate-based material as ferrous oxalate, thereby forming a precipitated ferrous oxalate and a first liquid phase comprising at least a part of the phosphate contained in the iron phosphate-based material; separating the precipitated ferrous oxalate from the first liquid phase, thereby obtaining the precipitated ferrous oxalate and the first liquid phase, and collecting the first liquid phase; optionally adding an acid to the precipitated ferrous oxalate, thereby dissolving the ferrous oxalate; and optionally recovering oxalic acid from the dissolved ferrous oxalate at least partially.

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 relates to a method for regulating and deacidifying in a bioleaching process of low-grade copper sulphide ore, aiming at the problem of excessive acid caused by excessive oxidation of pyrite in a dump leaching system, a thiocyanate bactericide is added into the bioleaching system of the low-grade copper sulphide ore, and the thiocyanate bactericide is dissolved in a spray liquid of the bioleaching system, and is added into the spray liquid of the bioleaching system; under the catalytic action of mineral leaching microorganisms, oxidation of ferrous ions is enhanced, so that the oxidation-reduction potential of a solution is increased, oxidation of pyrite is intensified, acid accumulation is excessive, the thiocyanate bactericide can remarkably inhibit the activity of part of sulfur-oxidizing bacteria and even kill part of sulfur-oxidizing bacteria, and therefore the activity of ferrous oxide is reduced; compared with the prior art, the method has the advantages that the sulfur oxidation activity of microorganisms is greatly influenced, but the oxidation influence on iron is relatively small, so that the acid leaching is reduced under the condition that the copper leaching of the copper sulfide ore is not influenced, the copper leaching is not influenced, the acid leaching is reduced, the production cost is reduced, the environmental influence is reduced, and the like.

To provide a heavy metal insolubilizing material for insolubilizing heavy metal contained in a heavy metal contaminant (for example, incineration ash, soil, and drainage water), which can exhibit an excellent insolubilization effect to a plurality of kinds of heave metal (for example, arsenic and hexavalent chromium), in a short time (for example, 2 to 3 hours).SOLUTION: A heavy metal insolubilizing material contains an iron compound composed of either or both of ferrous sulfate monohydrate and ferrous chloride tetrahydrate, and a magnesium compound composed of one or more selected from the group consisting of magnesium sulfate heptahydrate, magnesium sulfate nonhydrate, and magnesium sulfite hexahydrate. A ratio of the iron compound in the total amount of the iron compound and the magnesium compound is 5 to 80 mass%. The heavy metal insolubilizing material can be prepared in a powdery form.SELECTED DRAWING: None

The invention relates to a method and a system for producing an oxidant solution, comprising an electrochemical cell having an anode and a cathode, the method comprising the steps of: (i) supplying a raw electrolyte to a reaction region between the anode and the cathode, the raw electrolyte consisting of sulfate ions (SO42-) and ferrous ions (Fe2 +); (ii) during a run cycle, electrolyzing the feedstock electrolyte to produce an oxidized acid solution comprising peroxydisulfate (S2O8 < 2->) and iron ions (Fe < 3 + >); and (iii) supplying the oxidized acid solution. The oxidant solution is preferably used to leach metals from wastes including electronic wastes and metal-containing ores.

At least one embodiment of the invention provides a preparation method of sponge titanium, which comprises the following steps: pretreating bauxite tailings to obtain a first mixture; carrying out acid treatment on the first mixture, and filtering to obtain a second mixture; putting the second mixture into a reaction kettle containing an alkaline substance to react so as to convert the ferric titanate into titanate and ferric oxide or ferrous hydroxide to obtain a third mixture; carrying out suction filtration treatment on the third mixture to obtain a first solid phase and a first liquid phase, and drying and grinding the first solid phase; roasting the dried and ground first solid phase to form an iron elementary substance, and carrying out magnetic separation to remove the iron elementary substance; adding an acidic material into the first liquid phase for reaction to obtain metatitanic acid colloid, and washing the metatitanic acid colloid; the metatitanic acid colloid is subjected to calcination, chlorination reaction and replacement reaction in sequence to obtain the sponge titanium. The sponge titanium obtained through the preparation method is high in purity.

The invention provides a nickel-iron-manganese-copper-sodium electric precursor material and a preparation method and application thereof, and the preparation method comprises the following steps: carrying out a co-precipitation reaction on a ferrous source solution, a nickel-manganese-copper mixed salt solution, a precipitator solution and a complexing agent solution to obtain the nickel-iron-manganese-copper-sodium electric precursor material, the ferrous source solution comprises inorganic acid; the co-precipitation reaction comprises a seed crystal preparation stage and a particle growth stage which are carried out in sequence, and in the particle growth stage, the rotating speed of the reaction is reduced along with the increase of the particle size. According to the preparation method, the inorganic acid is added into the ferrous source solution, so that oxidation is prevented, the morphology of the precursor material is improved, introduction of excessive impurities is avoided, and material growth is further controlled in combination with the relationship between the particle size and the rotating speed, so that the morphology of the material is further improved, and the electrochemical performance of the material is improved.

This invention provides a method for preparing a tandem catalyst and its application in degrading organic matter in wastewater, belonging to the field of wastewater treatment technology. The tandem catalyst is prepared by co-precipitation of ferrous chloride, ferric chloride, and aluminum nitrate, followed by grinding and calcination with high-temperature kerosene and activated carbon. The tandem catalyst is then applied to degrade organic matter in wastewater. The tandem catalyst prepared by this invention comprises a hierarchical porous carbon support and a co-precipitate of iron(III) oxide and aluminum(III) oxide supported on the surface of the hierarchical porous carbon support. Using hierarchical porous carbon as the support and aluminum(III) oxide and iron(III) oxide in series as the catalyst facilitates the ozone decomposition of organic matter. The tandem catalyst of this invention can effectively degrade organic matter, achieving a degradation rate of over 95% for both total cyanide and ammonia nitrogen.

The invention belongs to the technical field of metallurgical ironmaking, and discloses a high-silicon iron ore pellet as well as a preparation method and application thereof. The preparation method of the high-silicon iron ore pellets comprises the following steps that S1, high-silicon iron ore, a binder and ferrous nitrate are mixed, hydrogen peroxide is added for pelletizing, and green pellets are obtained; and S2, the green pellets are dried, preheated and roasted, and the high-silicon iron ore pellets are obtained. The preparation method of the high-silicon iron ore pellets is high in process compatibility, the consolidation kinetics of the high-silicon iron ore under the low-temperature condition can be effectively enhanced according to the characteristics of the high-silicon iron ore, and the mechanical strength and metallurgical performance of the pellets are remarkably improved on the premise of not depending on high-temperature or long-time roasting; environment protection and efficient utilization of resources are considered, green low-carbon production of high-quality pellets is achieved, and the method is simple in process, controllable in cost and high in adaptability, has large-scale industrial popularization potential and is expected to promote transformation of the iron and steel industry to the green low-carbon direction.

The application provides a method for treating and recycling iron-containing waste sulfuric acid in titanium dioxide production, which is based on screening of a strain capable of treating iron-containing waste water in a low pH environment, and establishes a method for treating iron-containing waste sulfuric acid, which can effectively realize resource recycling. The waste water treatment bacteria used are Bacillus QD-QJ-062 strain, and the preservation number is CGMCC No.33725. The QD-QJ-062 strain of Bacillus screened by the application can effectively treat the iron-containing waste water in a low pH environment, promote the generation of ferrous oxalate precipitation, and generate ferrous oxalate by-products. The generated ferrous oxalate can be converted into ferrous sulfate by sulfuric acid, and oxalic acid can be recycled, thereby reducing the operation cost. The sulfuric acid solution after iron removal can be neutralized by limestone to generate high-purity gypsum, thereby realizing resource recycling and treatment.

The present application relates to the technical field of acid waste gas treatment, and provides a treatment process for acid waste gas, comprising the following steps: S1, absorbing the acid waste gas by a treatment agent; S2, spraying and absorbing the waste gas after S1 by a ferrous chloride solution; and S3, absorbing the waste gas after S2 by a sodium hydroxide absorption solution. Through the above technical scheme, the problems of low acid waste gas treatment rate and insufficient waste gas treatment in the prior art are solved.

The invention discloses a lithium iron phosphate positive electrode material recovery method, which comprises: (1) adding dilute phosphoric acid to positive electrode material powder to prepare a lithium iron phosphate slurry, and carrying out electrolysis extraction to recover the lithium element in the positive electrode material powder so as to obtain an iron phosphate slurry; and (2) adding concentrated sulfuric acid into the iron phosphate slurry obtained in the step (1) to carry out a dissolution reaction, then carrying out solid-liquid separation to obtain a ferric sulfate solution containing phosphoric acid, then adding iron blocks or iron powder to carry out a reaction, and then adjusting the iron-phosphorus ratio and the ferrous ion content of the system to obtain a ferrous solution meeting the requirements of ammonium-process iron phosphate. The recycling method of the lithium iron phosphate positive electrode material is simple in technological process, less in acid and alkali consumption, less in waste liquid and low in cost, valuable elements such as lithium, iron and phosphorus in the lithium iron phosphate positive electrode powder are recycled at low cost and high yield, and the extracted iron and phosphorus elements are presented in a ferrous solution and can be directly grafted with an existing ammonium-process iron phosphate device, so that the recycling method is suitable for industrial production. Good popularization prospects are realized.

The invention provides a ferromanganese oxide and a preparation method and application thereof, and belongs to the technical field of secondary batteries. The molecular formula of the ferromanganese oxide is MnxFeyAaBbO3, A is tetravalent metal, B is divalent metal, 0.19 < = x < = 1.8, 0.19 < = y < = 1.8, 0 < = a < = 0.1, 0 < = b < = 0.1, 1.9 < = x + y + 3 / 2a + 3b < = 2.1, and primary particles of the ferromanganese oxide are sheet-shaped. The ferromanganese oxide provided by the invention is of a sheet structure, and more active sites can be provided to support efficient electrochemical reaction, so that the electrochemical performance of the positive electrode material prepared by taking the ferromanganese oxide as the precursor is improved. According to the preparation method of the ferromanganese oxide, part of the ferrous hydroxide precipitate is dissolved under the overalkaline condition, so that the coprecipitation effect is achieved, and the use of a complexing agent is avoided.

The invention discloses a precipitation-loaded slow-release carbon-based iron fertilizer and a preparation method thereof. The preparation method specifically comprises the following steps: firstly, a biological crustacean heavy metal adsorbent is immersed in a calcium hydroxide solution, dried, and then immersed in a ferrous sulfate solution twice, and finally dried and granulated. The slow-release iron fertilizer is loaded by precipitation, and a precipitated ferric hydroxide, ferrous hydroxide mixture and excess ferric sulfate are uniformly dispersed and attached to the inside of pores of a porous adsorbent. Excess ferric sulfate can quickly provide iron ions to antagonize cadmium and arsenic ion absorption in the early growth stage of rice. Calcium sulfate encapsulates the precipitated ferric hydroxide and ferrous hydroxide in the porous adsorbent, which can achieve long-term slow-release of iron ions and reduce soil oxygen content. Iron ion antagonism is performed throughout the entire rice growth process. The precipitation-type adsorption loading method greatly increases the release cycle of the iron ions. The iron fertilizer of the invention has an excellent cadmium and arsenic antagonistic effect on rice and has excellent application prospects.

The invention discloses a ferrous sulfate purification method and a ferrous sulfate purified product, and the method comprises the following steps: dissolving a titanium dioxide by-product in deionized water to obtain a ferrous sulfate saturated solution; under the condition that reducing gas is introduced into the ferrous sulfate saturated solution, mixing sodium sulfide with the ferrous sulfate saturated solution, and filtering to obtain a first purified solution; mixing sodium sulfide with the first purified solution, and filtering to obtain a second purified solution; and carrying out concentration crystallization on the second purified solution, and carrying out suction filtration and drying to obtain a ferrous sulfate purified product. Iron powder does not need to be added, oxidation of ferrous ions is inhibited through reducing gas, sodium sulfide is added in stages to enable impurities with high activity to react to generate sulfide precipitates, the sulfide precipitates are filtered, the content of impurities such as titanium ions, magnesium ions, manganese ions and calcium ions is greatly reduced, the impurity removal effect is good, and finally concentration and crystallization are conducted through solubility difference. The purification purity of the ferrous sulfate purified product is generally as high as 99% or above.

The application discloses a method for preparing lithium iron phosphate by taking ferrous phosphide as raw material and a product, relates to the technical field of green and sustainable development of the steel industry and new energy materials, and comprises the following steps: preparing ferrous phosphide by taking steel slag and phosphorus tailings as raw materials, using nitric acid to leach the ferrous phosphide, controlling the pH of leaching to be 2.5-3, and controlling the leaching time to be 2-5 hours; adding phosphoric acid in the leaching solution, controlling the Fe / P molar ratio in the solution after adding the phosphoric acid to be 0.6-0.8; filtering the leaching solution, and roasting the filtered precipitate in an air atmosphere at 700-900 DEG C for 10-12 hours; mixing the roasted product with lithium hydroxide and glucose, and mixing the raw materials according to the molar ratio of FePO4:LiOH.H2O:C6H 12 O6 being 1:1.06:0.18-0.21; pressing the mixed raw materials into blocks, and roasting the blocks under an inert atmosphere at 700 DEG C for 10 hours, so that lithium iron phosphate is obtained. The application realizes bidirectional green development of the steel industry and the new energy industry by preparing lithium iron phosphate materials by using steel slag recovery products.

A process for the production of iron phosphate, comprising the following steps: (1) Mixing an iron phosphide waste, an acidic liquid, an oxidizing agent and an adsorbent with stirring, heating to leaching and subjecting the resulting mixture to solid-liquid separation to obtain a first filtrate and a first filter residue; (2) Adding an alkaline liquid to the first filtrate to adjust the pH of the first filtrate, maintaining a temperature of the resulting mixture, and subjecting the resulting mixture to solid-liquid separation to obtain a second filter residue and a second filtrate; and subjecting the second filter residue to heat treatment to obtain iron oxide; (3) Subjecting the iron oxide to high-energy ball milling and adding a surfactant for activation to obtain a slurry; (4) Adding an extraction agent and an acidic liquid to the second filtrate obtained in step (2), carrying out an extraction and separation on a resulting mixture and subjecting a resulting organic phase to back-extraction to obtain phosphoric acid; and (5) Mixing the slurry obtained in step (3) with the phosphoric acid, heating to enable a reaction, subjecting the resulting mixture to solid-liquid separation to obtain a solid, and washing and sintering the solid to obtain the iron phosphate; where in step (1) the iron phosphide waste comprises a mixture of FeP and Fe2P; in step (1) the acidic liquid contains at least two from the following group: nitric acid, sulfuric acid and hydrochloric acid; In step (1) the oxidizing agent is at least one selected from the group consisting of hydrogen peroxide, oxygen, nitric acid and sodium persulfate; wherein in step (2) the alkaline liquid is at least one selected from the group consisting of a NaOH solution, a KOH solution, ammonia water, a urea solution, NH4Cl, NH4HCO3, Na2CO3 and NaHCO3; In step (2) the pH of the first filtrate is adjusted to 2.5 to 5; and In step (5) the molar ratio of Fe in the slurry to P in the phosphoric acid is 1:1–2; heating to enable a reaction is carried out at a temperature of 50 °C to 80 °C for 20 to 60 min; and the iron phosphate has a D 50 from 2 µm to 6 µm, a tapped density of 0.80 g / cm³ 3 up to 1.30 g / cm³ 3 , and a specific surface area of ​​4 m² 2 / g up to 8 m 2 / g indicates.

The invention discloses a titanium dioxide waste acid concentration system and method, and belongs to the technical field of sulfuric acid process titanium dioxide production or similar waste acid concentration. The system comprises a primary concentration and ferrous separation module and a secondary concentration and ferrous separation module. The primary concentration and ferrous separation module realizes primary concentration and solid-liquid separation of waste acid through an evaporation concentration kettle, a flash tank and a primary diaphragm filter press; and the secondary concentration and ferrous separation module is used for carrying out deep concentration and secondary separation on the waste acid through a scraper evaporator and a secondary diaphragm filter press. The system adopts the technologies of ultrasonic descaling, stepped concentration and solid removal, partition temperature control film evaporation and the like, and is matched with a mirror surface level inner wall scraper evaporator and an adjustable rapping device, so that the problem of scaling blockage in the waste acid concentration process is effectively solved. The method can increase the concentration of waste acid to 60% or above, realizes continuous automatic operation, and has the advantages of low equipment investment, low operation cost, environmental friendliness, high resource recovery rate and the like.

The invention provides a preparation method and application of ferrous oxalate, and belongs to the field of comprehensive utilization of solid waste resources, the preparation method of the ferrous oxalate comprises the steps that iron ore waste residues are subjected to acid leaching treatment, and a first iron-containing solution is obtained; performing resin impurity removal on the first iron-containing solution to obtain a second iron-containing solution; and mixing the second iron-containing solution with a compound containing oxalate, and carrying out precipitation reaction to obtain ferrous oxalate. Then, the ferrous oxalate can be used as an iron source to be mixed with a lithium source, a phosphorus source, a carbon source and a solvent to obtain a mixture; and grinding and drying the mixture, and sequentially carrying out primary sintering and secondary sintering to obtain the lithium iron phosphate material. According to the technical scheme provided by the invention, the iron element can be extracted from the iron ore waste residues, the high-purity ferrous oxalate is prepared, and then the lithium iron phosphate material is prepared by taking the ferrous oxalate as an iron source, so that the preparation cost of the lithium iron phosphate material is effectively reduced, and efficient utilization of the iron ore waste residues is realized.

The present application relates to the technical field of abandoned pyrite area treatment, and particularly relates to a kind of abandoned pyrite area acid wastewater anti-silting ditch type processing system and method, including reaction ditch, the reaction ditch is divided into closed water inlet area, anoxic reaction zone, oxidation precipitation zone in sequence along the direction of acid wastewater communication by water distribution flower wall;The anoxic reaction zone is sequentially provided with neutralization reaction layer, barrier layer, cover layer from bottom to top;Water hole is provided on the water distribution flower wall, the water hole is below the top surface of the neutralization reaction layer, the liquid level of the closed water inlet area and the oxidation precipitation zone is higher than the water hole.The present application divides the reaction ditch into closed water inlet area, anoxic reaction zone, oxidation precipitation zone, avoids the oxidation of ferrous iron by anoxic environment of closed water inlet area and anoxic reaction zone, makes ferrous iron concentrated oxidation and precipitation in oxidation precipitation zone, realizes that neutralization, precipitation step subarea is completed, both can effectively treat iron-containing acid wastewater, and can solve the problem of too fast clogging and failure of reaction zone, ensure long-term operation of processing system.

The invention discloses an adsorbent for treating heavy metal ions in industrial wastewater and a preparation method of the adsorbent, and relates to the technical field of adsorbents. The heavy metal ion adsorbent takes ferric chloride hexahydrate and ferrous chloride tetrahydrate as iron sources, and sodium acetate and sodium polyacrylate are added into diethylene glycol; carrying out hydrothermal reaction to obtain carboxylated ferroferric oxide; l-cysteine is grafted to the surface of carboxylated ferroferric oxide in an amidation mode through an EDC.HCl / NHS activation system; 2-aminoethanesulfonic acid is introduced by adopting the same activation grafting strategy, and finally the multifunctional magnetic heavy metal ion adsorbent simultaneously containing three functional groups including carboxyl, sulfydryl and sulfo is prepared. The prepared heavy metal ion adsorbent has the synergistic effect of three functional groups including carboxyl, sulfydryl and sulfo, and broad-spectrum efficient adsorption of various heavy metal ions is achieved.

The application discloses a preparation method of zero-valent iron with a high Fe(II) content magnetite interface by regulating the redox intensity, and belongs to the field of water treatment. The method comprises the following steps: uniformly mixing zero-valent iron particles and ferrous ion solution at 20 DEG C-30 DEG C, regulating the initial pH value to 1-4 by using a sulfuric acid solution, adding a sulfur ion solution after 20 min of reaction and reacting for another 5 min, wherein the mass ratio of the added sulfur ion to the initial ferrous ion is 0.2-0.4:1; after the reaction is completed, the zero-valent iron particles are separated by magnetism, and are dried in a vacuum oven at 40 DEG C-60 DEG C for 4-12 h to obtain Fe3O4@mZVI materials. The zero-valent iron composite material with a high Fe(II) content magnetite interface prepared by the method can be prepared in an open system without controlling the anaerobic reaction atmosphere environment. Meanwhile, the ferrous ion is oxidized by using air, and no external oxidizing agent is needed, so that the method has the advantages of simple and rapid preparation and low cost. In the preparation process, the sulfur ion is added to regulate the redox reaction degree, the proportion of Fe(II) on the material surface is significantly improved, and the zero-valent iron composite material has better reaction activity and durability for pollutant removal.

The present invention provides a printed metal part. The alloy has the following composition: 69.2 to 89.1 wt.% Fe; 7.25 to 16.0 wt.% Cr; 0.01 to 10.0 wt.% Nb; 0.5 to 4.0 wt.% Mo; 0.03 to 0.4 wt.% C; and optionally one or more of Ni, Cu, Si, W, Mn, N, and B. The printed metal part has a tensile strength of at least 1300 MPa, a yield strength of at least 700 MPa, an elongation of at least 4.0%, and a hardness of at least 45 HRC.