443 results about "Ferrous" patented technology

The invention belongs to the technical field of high-purity metal preparation, and particularly discloses a method for preparing 5N-grade ultrapure iron. The method is characterized by comprising the following steps: electrolyzing industrial pure iron to prepare liquid; carrying out ion exchange treatment on the solution to reduce near-iron elements such as Co, Ni, Cu and Zn and impurities in the solution, so that ferrous ions are effectively enriched; then, the solution with the near iron element removed serves as electrolyte for electrolysis to prepare pure iron; in the electrolysis process, a ruthenium-coated titanium plate is used as an anode, and a pure titanium plate is used as a cathode; performing high-temperature vacuum annealing treatment and high-temperature atmosphere reduction on a product obtained by electrolysis to remove free-state and combined-state hydrogen and oxygen elements in the product; the 5N-grade ultrapure iron is prepared by matching the steps with a corresponding process. The method has the advantages that the removal of near-iron elements and gas elements is realized by combining solution purification, electrolysis, vacuum annealing and reduction from enrichment and purification of ferrous ions, and the purpose of preparing 5N-grade ultrapure iron through electrolysis is realized.

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 preparation method and application of high-dispersion small-particle-size iron phosphate. The method comprises the following steps: 1) dissolving an iron source in a phosphoric acid solution to obtain ferrous dihydrogen phosphate; 2) adding a cellulose additive into the solution obtained in the step 1), stirring and heating; 3) heating to 60-95 DEG C, adding hydrogen peroxide, carrying out oxidation reaction, and aging; and 4) filtering the solvent, washing, drying, and roasting to obtain the iron phosphate. The iron phosphate provided by the invention is in a sheet shape, no agglomeration exists between sheets, the particle size can be as low as 1 micron or below, the grinding efficiency of lithium iron phosphate can be effectively improved, and the electrochemical performance of a lithium battery positive electrode material prepared from the lithium iron phosphate can be effectively improved.

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 magnetic biochar-based saline-alkali soil conditioner as well as a preparation method and application thereof, after a biochar material is loaded on ferrous iron, the biochar material is subjected to alkaline oxidation to obtain ferroferric oxide and a porous biochar material in a stable state, and finally activated humic acid, betaine, trehalose and melatonin are combined with magnetic biochar. The magnetic charcoal-based saline-alkali soil conditioner is low in price and easy to obtain and has a good improvement effect on physicochemical properties of saline-alkali soil and promotion of rice growth, and the preparation process is simple and easy to operate.

The invention discloses a method for preparing high-quality iron phosphate in a short process, and belongs to the field of battery material manufacturing. The method comprises the following steps: dissolving iron powder with phosphoric acid to prepare a ferrous phosphate solution, then transferring the solution into a pressurized reaction kettle, blowing high-speed oxygen to oxidize ferrous phosphate into ferric phosphate, adding ammonia water to control the pH value to be 1.5-2.0, and carrying out solid-liquid separation to obtain the water-containing amorphous ferric phosphate, after washing is finished, a water-containing material is fed into a muffle furnace to be subjected to stepped calcination, dehydration and crystal transformation are completed, and the alpha monoclinic system iron phosphate is obtained. The method provided by the invention is short in process flow and low in energy consumption, the oxidant is easy to obtain and safe, the particle size uniformity of reaction materials is good, and the prepared iron phosphate is uniform in particle size, regular in structure and stable in iron-phosphorus ratio and is a high-quality precursor material.

The invention provides a method for preparing an iron-chromium electrolyte and electronic-grade ferrous chloride by using a stainless steel waste liquid. The method comprises the following steps: firstly, adding elemental iron and / or elemental chromium into the stainless steel waste liquid to obtain a chromium-containing ferrous chloride solution; then, sulfide is added, and nickel is removed; adding iron powder to increase the pH value to obtain chromium hydroxide precipitate and a ferrous chloride solution; dissolving chromic hydroxide in hydrochloric acid to obtain a chromic chloride solution; purifying the ferrous chloride solution to obtain an electronic-grade ferrous chloride crystal; and finally, adding a chromium chloride solution, the electronic-grade ferrous chloride crystal and hydrochloric acid according to a certain proportion, and stirring and mixing to obtain the iron-chromium electrolyte. The ferrous chloride prepared by the steps is relatively high in purity and less in waste; meanwhile, the prepared electrolyte is good in electrical property, low in attenuation rate and low in cost, the purpose of comprehensive recycling of resources is achieved, and the general trend of technical improvement is met.

Provided are a preparation method for lithium iron phosphate, a positive electrode active material, a positive electrode plate, a battery, and a power-consuming device. The preparation method for lithium iron phosphate comprises: dissolving a first iron source, a second iron source, a lithium source and a phosphorus source in a solvent to obtain a mixed slurry; and sintering the mixed slurry to obtain lithium iron phosphate, wherein the first iron source comprises at least one of iron oxide or first iron phosphate, and the second iron source comprises at least one of second iron phosphate or ferrous oxalate, the first iron phosphate has an iron to phosphorus ratio of 0.97-0.985, and the second iron phosphate has an iron to phosphorus ratio of 0.93-0.96. The primary particles of lithium iron phosphate, which have different particle sizes, can be mixed and matched, thus improving the compact density of lithium iron phosphate and the energy density of the battery.

The invention discloses a preparation method and application of morphology-compounded iron phosphate. The preparation method comprises the following steps: S1, dissolving an iron source in a phosphoric acid solution to obtain a ferrous dihydrogen phosphate solution; s2, heating and stirring, adding a part of hydrogen peroxide, and carrying out a first-stage oxidation reaction to obtain a turbid liquid; s3, adding maleic anhydride into the obtained turbid liquid, fully mixing and stirring, adding the rest of hydrogen peroxide, carrying out two-stage oxidation reaction, and aging; s4, after the solvent is filtered out, washing, drying and roasting are conducted, and iron phosphate is obtained. The iron phosphate prepared by the method disclosed by the invention has two completely different morphologies, i.e., a sheet shape and a block shape, and the particle sizes of the sheet shape and the block shape are equivalent, so that the lithium iron phosphate does not need to be prepared through large and small particle grading, and meanwhile, the obtained lithium iron phosphate has the advantages of high compaction density and large discharge capacity.

The invention relates to the technical field of pendimethalin wastewater treatment, in particular to a pendimethalin wastewater treatment method which comprises the following steps: step 1, adding ferrous oxide or ferrous hydroxide into wastewater, and adjusting the pH value of the wastewater to be neutral; 2, adjusting the pH value of the primary filtrate to 2-5 by using an inorganic acid, and adding an iron-carbon mixture with the mass ratio of 1: (0.5-2) to carry out an oxidation-reduction reaction; and step 3, introducing the secondary filtrate into 2-5 reaction kettles which are connected in series, and adding hydrogen peroxide for 1-3 times according to the mass ratio of hydrogen peroxide to COD (Chemical Oxygen Demand) of (15-25): 1. According to the pendimethalin wastewater treatment method provided by the invention, the iron-carbon mixture generates a primary battery effect in the solution, nitrate radicals can be quickly reduced into nitrogen oxides or ammonia gas, the nitrate radicals are efficiently and quickly treated, and meanwhile, iron ions and ferrous ions can finally generate corresponding hydroxides to be separated out.

A grey cast iron may have within a ferrous matrix: an amount of carbon between 3.60 and 3.90% by weight; an amount of silicon between 1.40 and 1.90% by weight; an amount of titanium not higher than 0.10% by weight; an amount of boron between 0.04 and 0.07% by weight; an amount of vanadium between 0.07 and 0.14% by weight; an amount of manganese between 0.60% and 0.90% by weight; an amount of nickel not higher than 0.20% by weight; an amount of chromium not higher than 0.35% by weight; an amount of copper not higher than 0.35% by weight; an amount of phosphorus not higher than 0.10% by weight; an amount of sulphur not higher than 0.12% by weight; an amount of tin not higher than 0.10% by weight; an amount of molybdenum not higher than 0.10% by weight.

The invention relates to the technical field of iron ore tailing resource utilization, in particular to a method for preparing iron oxide yellow by leaching iron ore tailings through an advanced oxidation technology, which comprises the following steps: adding a required amount of iron ore tailing powder into a persulfate solution, stirring to react, adding a reducing agent, boiling, filtering, adding alkali liquor to adjust the pH value, and filtering, thereby obtaining the iron oxide yellow. Pure liquid containing ferrous ions is obtained; taking part of the pure solution containing ferrous ions, and adding a potassium hydroxide solution to obtain an iron oxide yellow seed crystal solution; adding a pure solution containing ferrous ions into the iron oxide yellow seed crystal solution, adding an alkali solution to adjust the pH value, reacting, and separating and drying a product to obtain the iron oxide yellow. According to the method, the persulfate is adopted to leach iron from the iron ore tailings, and the iron oxide yellow is prepared from the leachate; harmless treatment of the iron ore tailings and value-added utilization of valuable resources are achieved, the raw material source of the iron oxide yellow industry is widened, and a wider prospect is provided for development of iron oxide yellow.

The present invention provides a glass sheet having soda-lime-silica glass composition with a high visible light transmittance (LtC) of at least 89% with a dominant wavelength (DW) from about 490 to 505 nanometers and purity (Pe) of no more than 1% for control thickness of 5.66 mm and methods of making the same. The glass composition comprising a low iron raw material, a total iron oxide (Fe2O3) of 0.02 to 0.06 wt. %, ferrous (FeO) from 0.006 to 0.02 wt. %, redox (FeO / Fe2O3) from about 0.30 to 0.55, Cr2O3 from about 0.3 to 10 ppm, TiO2 from about 50 to 500 ppm, SnO2 from about 10 to 500 ppm, and a critical amount from about 0.10 to 0.25 wt. % of SO3. The low content of iron oxide is achieved by the partial substitution of regular raw materials by low iron raw materials, with a complete substitution of regular dolomite by a low iron dolomite with a maximum content of 0.020 wt. % Fe2O3.

The invention discloses a precipitation-supported slow-release carbon-based iron fertilizer and a preparation method thereof, and the preparation method specifically comprises the following steps: firstly, putting a biological carapace heavy metal adsorbent into a calcium hydroxide solution for dipping, drying, then putting the biological carapace heavy metal adsorbent into a ferrous sulfate solution for dipping in two times, and finally drying and granulating. Precipitated ferric hydroxide, a ferrous hydroxide mixture and excessive ferric sulfate are uniformly dispersed and attached to the interiors of pore channels of the porous adsorbent, and the excessive ferric sulfate can quickly provide iron ions for antagonistic cadmium and arsenic ion absorption in the early growth stage of rice. Precipitated ferric hydroxide and ferrous hydroxide wrapped by calcium sulfate in the porous adsorbent not only can realize long-acting slow release of iron ions, but also can reduce the oxygen content of soil, and iron ion antagonism and precipitation type adsorption loading modes are carried out in the whole growth process of rice, so that the release period of the iron ions is greatly prolonged, and the soil quality is improved. The iron fertilizer disclosed by the invention has an excellent rice cadmium-arsenic antagonism effect and has an excellent application prospect.

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 an iron removal method for laterite-nickel ore leaching pulp, and relates to the technical field of laterite-nickel ore hydrometallurgy. The iron removal method comprises the following steps that the pH value of laterite-nickel ore leaching ore pulp is adjusted to A1, a first mixture is introduced for a first reaction, and first intermediate liquid is obtained; adjusting the pH value of the first intermediate solution to A2, and introducing the second mixture to carry out a second reaction to obtain a second intermediate solution; adjusting the pH value of the second intermediate solution to A3, and carrying out a third reaction to obtain a third intermediate solution; wherein A1 < A2 < A3 < = 6, the first mixture and the second mixture both comprise SO2-containing substances and O2-containing gas, the ferrous content of leached ore pulp can be effectively reduced, and therefore the purity and quality of nickel-cobalt precipitates are improved.

The invention relates to the technical field of constructed wetlands, in particular to a constructed wetland iron-carbon-manganese composite filler capable of efficiently removing nitrogen and phosphorus. According to the filler, the manganese ore layer is arranged behind the iron-carbon micro-electrolysis layer, the microenvironment in the iron-carbon micro-electrolysis constructed wetland is adjusted through manganese ore, iron and manganese exist at the same time and can serve as electron donors for microbial denitrification, the effect is better than that of single use of iron, meanwhile, the oxidation capacity of high-valence manganese ions is utilized, and the denitrification efficiency is improved. The ammonia nitrogen in the iron oxide carbon wetland is inhibited or re-oxidized, so that the total nitrogen removal capability of the wetland is enhanced, and efficient nitrogen removal is realized; the manganese ore is large in specific surface area and can adsorb iron ions in water, iron and manganese separated out of the water are effectively removed, and the problem that the dissolution concentration of the iron ions is high is solved; phosphate radicals are adsorbed and removed mainly through ligand exchange with hydroxyl on the surface of manganese nodule, iron ions and ferrous ions dissolved out from the scrap iron are combined with influent phosphate to form precipitates such as iron phosphate, and a very good effect on removal of total phosphorus is achieved.

The invention belongs to the technical field of urban water environment treatment and restoration, and discloses a method for improving the micro-ecological environment of bottom mud of an urban black and odorous river. The method specifically comprises the following steps that 1, calcium nitrate with the amount 1.6-1.8 times of theoretical calculation amount is added according to the AVS content in the black and odorous bottom mud to be repaired; 2, after the calcium nitrate reacts, calcium peroxide (CaO2) with the amount 1.3-2.0 times of the theoretical calculation amount is added. According to different reaction processes of AVS and ferrous iron in the black and odorous bottom mud and different oxidation capacities of calcium nitrate and CaO2, calcium nitrate is added firstly, and then CaO2 is added, so that removal of ferrous iron, AVS and organic matters in the black and odorous bottom mud is enhanced, chemical agents are scientifically and efficiently used, and the micro-ecological environment of the black and odorous bottom mud is continuously and effectively improved.

The invention discloses synthesis of a cup crown compound adsorption material and a method for deeply and selectively extracting indium from an acid complex system, and belongs to the technical field of non-ferrous metallurgy. According to the synthesis of the cup-crown compound adsorption material and the method for deeply and selectively extracting indium from the acid complex system, based on the pre-organizability and complementary molecular design principle of subject-object chemistry, a 15-crown-5 ether subunit is introduced into a calix [4] arene structure to form a cup-crown supramolecular compound; and furthermore, the material is loaded on the surface of SiO2 particles to form a stable adsorption material, so that deep selective separation and extraction of indium in an acidic complex system can be realized.

The invention provides a method for preparing high-purity manganese sulfate by taking pyrolusite and pyrite as raw materials, which comprises the following steps: carrying out reduction reaction on the pyrolusite and the pyrite by adopting acid leaching to obtain a manganese sulfate solution, and continuously feeding the pyrolusite until ferrous ions in the system are completely oxidized into iron ions; adding a pH regulator to remove iron, adding a vulcanizing agent to remove heavy metals, adding a pH regulator to remove silicon and aluminum, and carrying out solid-liquid separation to obtain a manganese sulfate solution containing calcium and magnesium; adding a fluorinating agent into the manganese sulfate solution containing calcium and magnesium to remove calcium and magnesium, and carrying out solid-liquid separation to obtain a fluorine-containing high-purity manganese sulfate solution; and extracting the fluorine-containing high-purity manganese sulfate solution to obtain a fluorine-containing organic phase and battery-grade high-purity manganese sulfate. According to the method, the medicament cost in the removal process is greatly reduced, namely, the raw material pyrolusite is used for replacing an external oxidant to oxidize Fe < 2 + > in a system, and a large amount of jarosite and sodium jarosite are generated in situ, so that complete removal of potassium, sodium and iron is realized.

A method for preparing iron phosphate from an iron phosphorus slag includes: adding the iron phosphorus slag into an alkaline solution to carry out a reaction followed by a solid-liquid separation to obtain a residue and a first filtrate containing meta-aluminate ion and phosphate ion; adding an acid solution into the first filtrate to carry out an aluminum-removing reaction followed by a solid-liquid separation to obtain a second filtrate containing phosphate ion; mixing the residue with an acid solution to carry out a carbon-removing reaction followed by a solid-liquid separation to obtain a carbon residue and a third filtrate containing iron ion, titanium ion, and copper ion; adding metallic iron into the third filtrate to carry out a titanium and copper-removing reaction followed by a solid-liquid separation to obtain a fourth filtrate containing ferrous ion; mixing an oxidant, the second filtrate, and the fourth filtrate to carry out a reaction followed by a solid-liquid separation and a sintering process in sequence to obtain the iron phosphate.

The utility model discloses a welding wire copper plating device which comprises a copper plating tank, guide wheels, a lifting plate, a mixing tank, a solute tank, a solvent tank and a sulfuric acid tank, an air cylinder is arranged on the lower portion of the copper plating tank, and the bottom of the copper plating tank is further connected with the mixing tank through a return pipe. And a copper sulfate content detector, a ferrous ion detector and a sulfuric acid concentration meter are respectively arranged on the return pipe and are used for detecting the copper ion concentration, the ferrous ion concentration and the hydrogen ion concentration in the plating solution. A copper sulfate solution and a sulfuric acid solution are added into the mixing pool in time to balance the ion change condition in the solution, it is guaranteed that the ion concentration in the plating solution is in the optimal copper plating state, and the copper plating stability during copper plating can be effectively improved; when the concentration of ferrous ions exceeds the standard, the lifting plate is lifted to divide the copper plating tank into two chambers, and then a new plating solution is added, so that the solution can be replaced without shutdown, and the working efficiency is effectively improved.

Ferrous and non-ferrous materials are identified and classified in a subject using a machine learning model that receives single-energy CT image data as an input. The machine learning model may be trained on single-energy CT image data. Additionally or alternatively, the machine learning model may be trained on dual-energy CT image data, geometrical data about metal objects, CT number data derived from the single-energy and / or dual-energy CT image data, and / or acquisition parameter data pertaining to acquisition parameters used when acquiring the single-energy and / or dual-energy CT image data. Single-energy CT image data acquired from a subject is input to the machine learning model, generating classified feature data as an output. The classified feature data indicate the presence of ferrous metal in the subject.

The invention discloses a method for preparing iron oxide red by using acidic ferrous wastewater, and belongs to the technical field of iron oxide pigments. The method comprises the following steps: by taking acidic ferrous wastewater generated by an iron oxide red factory as a raw material, adjusting the pH value, adding iron powder and phosphate to remove impurities, and carrying out solid-liquid separation to obtain a high-purity ferrous sulfate solution; and concentrating and crystallizing the obtained ferrous sulfate solution, dehydrating and drying, crushing and grinding, calcining at high temperature, and crushing to obtain the high-purity iron oxide red. According to the method, the high-purity iron oxide red pigment is obtained by firstly adjusting the pH value, then adding the iron powder and the phosphate to remove impurities, then separating out FeSO4. 7H2O by utilizing a crystallization technology, dehydrating, drying and then carrying out high-temperature calcination, the process is reasonable, the preparation method is simple and feasible, and the method is suitable for industrial production. Iron oxide red production wastewater can be comprehensively utilized, and the product quality is equivalent to or partially superior to that of precipitated iron oxide red.

The invention relates to an electrolyte and a preparation method thereof, a zinc-iron flow battery, a power utilization device and an energy storage device. The electrolyte comprises the following components: ferrous cyanide salt, alkali, a catalyst and water; the catalyst comprises a compound with the following structural formula: # imgabs0 #, wherein each R is respectively and independently 4-carboxyl phenyl, 4-sulfonyl phenyl, 4-aminophenyl or 4-phosphorous acid; m is iron (III), cobalt (II), manganese (II) or nickel (II). The electrolyte is beneficial to electron and proton transfer and can effectively reduce an electrochemical reaction energy barrier, so that the electrochemical reaction rate and the ionic conductivity are improved, the battery energy efficiency is improved, and the voltage loss is reduced.

The invention discloses a method for preparing iron oxide and calcium chloride by electrochemically recovering iron-containing waste hydrochloric acid, and belongs to the technical field of waste acid treatment. The method comprises the following steps: S1, respectively putting a cathode and an anode at two ends of an electrolytic cell, putting a diaphragm to separate the cathode and the anode, filtering the iron-containing waste hydrochloric acid, removing suspended matters and solid residues, and introducing the iron-containing waste hydrochloric acid into the electrolytic cell; s2, measuring the content of iron element and the content of free acid in the iron-containing waste hydrochloric acid, and adding a neutralizing agent to neutralize redundant free acid; s3, applying voltage between the cathode and the anode according to the content of the iron element, performing electrolytic reaction to generate an oxidation intermediate, and oxidizing the iron element by using the oxidation intermediate to obtain a precipitate iron oxide and a calcium chloride solution; and S4, adding a proper amount of water into the reaction solution for dilution, filtering to obtain iron oxide, and concentrating the filtrate to obtain calcium chloride. According to the method, the oxidation intermediate generated by waste hydrochloric acid electrolysis is used as the oxidizing agent, the ferrous ions in the waste hydrochloric acid are selectively oxidized, other oxidizing agents do not need to be additionally added, new impurities cannot be generated in the oxidation process, the treatment time is short, the product is controllable, and remarkable economic benefits and social benefits are achieved.

The invention provides a preparation method for preparing a high-compaction lithium iron phosphate positive electrode material by utilizing double-iron-source composite grade matching. The preparation method comprises the following steps: adding ferrous sulfate and phosphoric acid into pure water, and fully mixing to obtain a solution; dividing the solution into a solution A and a solution B; adding a certain amount of a metal doping source material, an oxidizing agent and phosphoric acid into the solution A, and controlling the pH to be 1-3 to obtain iron phosphate; adding a certain amount of metal doped source material and ammonia water into the solution B, and controlling the pH to be 5-6 to obtain ferrous phosphate; the preparation method comprises the following steps: respectively sanding and spraying iron phosphate and ferrous phosphate with a lithium source, a carbon source and pure water according to a molar ratio to obtain a lithium iron phosphate yellow material A and a lithium iron phosphate yellow material B; calcining the yellow material A in a furnace to obtain a precursor A, calcining the yellow material B in the furnace to obtain a precursor B, mixing the precursor A and the precursor B according to a certain mass ratio, and calcining to obtain a finished product. The method is simple in technological process, can be combined with actual production, and is very effective for improving the compaction density and the electrical property.

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 discloses a method for recovering fine iron powder, and relates to the technical field of resource recovery. The invention provides a process route of hydrochloric acid leaching, iron powder reduction, sulfuration impurity removal, evaporative crystallization, size washing and roasting, and impurities such as Cu and Co can be removed through iron powder reduction; then the characteristic that Ksp of NiS and CoS is smaller than that of FeS is utilized, FeS is used for sulfuration impurity removal, and precipitation and recovery of Ni and Co can be completed under the condition that Fe is not lost; finally, through evaporative crystallization, residual trace impurity elements in the impurity removal liquid can be enriched in the solution and are prevented from entering ferrous chloride crystals; and ferrous chloride can be efficiently converted into iron oxide red (or iron oxide yellow) through a roasting process, so that the equipment investment is reduced. According to the method, through optimization of the whole process, the fine iron powder generated by high-grade matte nickel hydrometallurgy can be converted into high-purity iron oxide red (or iron oxide yellow) in a recycling mode, and impurities such as Ni, Cu and Co in the fine iron powder can be effectively recycled.

A magnetic-assisted suction cup mounting assembly and method for semi-permanently attaching to a ferrous material surface comprises a suction cup and at least one magnet spatially arranged with respect to the suction cup and providing additional fixturing of the suction cup to the ferrous material surface. One method for semi-permanently attaching the mounting assembly to the ferrous material surface comprises positioning a plurality of magnets in a raised position above a peripheral edge surface of a suction cup, positioning the suction cup on the ferrous material surface and drawing a vacuum between the suction cup and the ferrous material surface. Then repositioning the plurality of magnets to a lowered position in contact with the ferrous material surface.