868 results about "Ferromanganese" patented technology

The invention discloses a preparation method of a high-compaction lithium manganese iron phosphate positive electrode material, which comprises the following steps: placing a manganese source, an iron source and a phosphorus source in deionized water, stirring, carrying out primary high-speed ball milling, carrying out constant-temperature water bath, adding an oxidizing agent, stirring and oxidizing, and drying the slurry to obtain manganese iron phosphate precursor powder; carrying out primary sintering on the ferromanganese phosphate precursor powder to obtain a ferromanganese phosphate primary sintering material; putting the ferromanganese phosphate primary sintering material into deionized water, adding a lithium source and a carbon source at the same time, and performing stirring, secondary high-speed ball milling and drying to obtain lithium ferromanganese phosphate precursor powder; and carrying out secondary sintering on the lithium manganese iron phosphate precursor powder to obtain the high-compaction lithium manganese iron phosphate positive electrode material. The void ratio is well reduced and good carbon coating is realized by means of secondary grinding and secondary sintering, and compared with the prior art, the method has the advantages that good capacity can be maintained, the powder compaction density of the material can be improved, the conductivity can be improved, and the specific surface area of the material can be effectively reduced.

The invention relates to the technical field of electrochemistry, and particularly discloses a positive pole piece, an electrochemical device comprising the positive pole piece and an electric device. The positive pole piece comprises a first active material with a particle size of 4-20 [mu] m and a second active material with a particle size of 200-600 nm, the first active material comprises lithium manganese iron phosphate with the manganese content of m%, the second active material comprises lithium manganese iron phosphate and / or lithium iron phosphate with the manganese content of n%, and m and n meet the condition that m-n is larger than or equal to 15 and smaller than or equal to 85. According to the invention, by controlling the particle size distribution in the positive electrode active material and the manganese content relationship, the electrochemical device containing the positive electrode plate has excellent fast charging performance and energy density.

The invention discloses a modified carbon-coated sodium manganese ferric phosphate pyrophosphate / sodium ferric phosphate pyrophosphate positive electrode material as well as a preparation method and application thereof, and relates to the technical field of new energy materials. The preparation method comprises the following steps: preparing MnFe-MOF from a manganese source, a first iron source and a first organic ligand under a hydrothermal reaction; a second iron source, the MnFe-MOF and a second organic ligand are subjected to a hydrothermal reaction, and MnFe-MOF / Fe-MOF is obtained; uniformly mixing with a sodium source and a phosphorus source, and sintering to obtain a positive electrode material; and carrying out high-temperature gas-phase etching treatment to obtain the fluorine-doped carbon-coated modified sodium manganese ferric phosphate pyrophosphate / sodium ferric phosphate pyrophosphate positive electrode material. The material disclosed by the invention has a coating modified structure, so that an interface side reaction caused by direct contact between sodium ferromanganese phosphate and an electrolyte can be effectively avoided, a manganese dissolution phenomenon is reduced, and the structural stability of the material is improved; and meanwhile, the material has high conductivity, excellent structural stability, excellent long cycle life and excellent rate capability.

The invention discloses a method for preparing a manganese iron phosphate precursor by recycling waste lithium manganese iron phosphate, and belongs to the technical field of lithium ion batteries. The invention provides a method for preparing a manganese iron phosphate precursor by recycling waste lithium manganese iron phosphate, which comprises the following steps: by taking waste lithium manganese iron phosphate battery powder as a raw material, carrying out acid dissolution and filtration to remove graphite and part of impurities; adjusting the pH value of the filtrate to obtain a lithium-ion-rich solution and a ferromanganese precipitate, and adding sodium carbonate into the lithium-ion-rich solution for concentration and crystallization to obtain battery-grade lithium carbonate; carrying out acid dissolution on the ferromanganese precipitate, removing copper and aluminum impurities in the solution, adjusting the ratio of ferromanganese to phosphorus, and mixing with liquid caustic soda in a nitrogen atmosphere to obtain a ferromanganese phosphate precursor; according to the method, the problems of incomplete recovery and insufficient impurity removal of the manganese iron phosphate lithium battery are solved, the battery-grade lithium carbonate and the manganese iron phosphate precursor are prepared during recovery, the value of the recovered product is improved, and the production requirement of the lithium ion battery is met.

The invention discloses a direct-current hollow electrode hydrogen plasma furnace mineral powder smelting system and method and application, and belongs to the technical field of hydrogen metallurgy. The system comprises a hollow electrode gas powder injection hydrogen plasma gun system, a direct current bottom electrode ore-smelting electric furnace system, a fine ore and hydrogen supply system and the like. The hollow electrode and the furnace bottom electrode form a direct-current arc, hydrogen carrying mineral powder is sprayed into an arc area to generate high-temperature hydrogen plasma, mineral powder reduction is achieved, and metal and slag are separated. According to the method, hydrogen serves as a reducing agent, carbon emission is reduced, the reaction efficiency is high, energy consumption is low, and the method can be used for steelmaking, smelting of micro-carbon ferromanganese and titanium slag and recovery of valuable metal in nonferrous smelting waste slag and has good green metallurgy application prospects.

The invention discloses a preparation method of a lithium manganese iron phosphate precursor, which comprises the following steps: mixing a manganese source and an iron source according to the molar ratio of Mn < 2 + > to Fe < 2 + > of (1.5-4): 1, adding water to prepare a manganese and iron ion mixed solution with the total concentration of Mn < 2 + > and Fe < 2 + > of 1-2mol / L, then dropwise adding the manganese and iron ion mixed solution and a precipitator into a base solution at the same time to obtain a reaction mixed solution, carrying out heat preservation and aging on the reaction mixed solution, then carrying out solid-liquid separation to obtain a filter cake, sequentially washing, drying and calcining the filter cake to obtain ferromanganese oxide, and then preparing a lithium iron manganese phosphate material by taking the obtained ferromanganese oxide as a lithium iron manganese phosphate precursor; according to the method, the soluble manganese source and the iron source are adopted for coprecipitation, and the manganese-iron ratio, the reaction rate, the pH and the reaction temperature are controlled, so that stable manganese-iron oxide with uniformly mixed manganese and iron is prepared, the stability of the further prepared lithium manganese-iron phosphate material is higher, and the electrochemical performance of the lithium manganese-iron phosphate material is effectively improved.

The present invention relates to a new method for preparing a ferromanganese oxalate precursor. The method comprises the following steps: mixing a water-soluble manganese salt, a water-soluble iron salt, a doping auxiliary agent 1 and a water-soluble oxalate in a water-organic solvent system, and subjecting same to a coprecipitation reaction. The present invention further relates to a method for preparing a lithium iron manganese phosphate positive electrode material. The method comprises the following steps: mixing the ferromanganese oxalate precursor with a lithium source, a phosphorus source and a doping auxiliary agent 2, drying same, then subjecting same to low-temperature roasting to obtain a lithium iron manganese phosphate precursor, mixing the precursor with an organic carbon source, then drying the mixture, and subjecting the mixture to high-temperature sintering, so as to obtain a carbon-coated lithium iron manganese phosphate positive electrode material. The present invention further relates to the ferromanganese oxalate precursor and the lithium iron manganese phosphate positive electrode material prepared by these methods.

The invention provides a lithium manganese iron phosphate material and a preparation method and application thereof.The preparation method comprises the steps that firstly, an iron source, a manganese source, a phosphorus source and a fluorine source are mixed and react to prepare a manganese iron phosphate precursor; and then preparing the lithium manganese iron phosphate material through double-step compounding of a carbon source and operations such as multiple times of grinding and sintering of an intermediate mixed material in the preparation process. According to the preparation method, firstly, a fluorine source is added into a ferromanganese phosphate precursor, and then substances such as a lithium source are added into the prepared ferromanganese phosphate precursor, so that the obtained lithium ferromanganese phosphate material can give full play to the current transmission effect of lithium in the material on the basis of inheriting the performance of the ferromanganese phosphate precursor material. The compaction performance and the cycle performance of the lithium manganese iron phosphate material are further improved through double-step carbon source compounding and repeated grinding, sintering and other operations of an intermediate mixture in the preparation process. In addition, the preparation method is simple in process and convenient to operate, and the obtained composite material is stable in performance and high in repeatability.

The invention provides a positive electrode active material as well as a preparation method and application thereof. The positive electrode active material comprises secondary particles consisting of primary particles, each primary particle comprises an inner core and a carbon coating layer arranged on at least part of the surface of the inner core; the inner core comprises a solid solution formed by lithium iron manganese phosphate and lithium manganate; the primary particles comprise primary particles A and primary particles B, the particle size of the primary particles A is 50-200nm, and the median particle size D50 is 80-120nm; the particle size of the primary particles B is 400-800 nm, and the median particle size D50 is 500-600 nm. The positive electrode active material has relatively high powder compaction density and ion transmission capability, and the electrochemical performance and energy density of the lithium ion battery can be effectively improved.

The invention provides a preparation method of a lithium manganese iron phosphate material, and relates to the technical field of positive electrode materials. The preparation method of the lithium manganese iron phosphate material comprises the following steps: mixing a first raw material component consisting of ferromanganese oxalate, a first lithium source, a first phosphorus source, a first carbon source and a first doping agent, adding deionized water, grinding, and then carrying out spray drying to obtain a precursor A; mixing a second raw material component consisting of carbon-coated ferromanganese oxalate, a second lithium source, a second phosphorus source, a second carbon source and a second doping agent, adding deionized water, grinding, and performing spray drying to obtain a precursor B; and uniformly mixing the precursor A and the precursor B, sintering in an inert atmosphere, and crushing to obtain the lithium manganese iron phosphate material. According to the lithium manganese iron phosphate material, on the premise of ensuring high specific capacity, relatively high compaction density and relatively high rate capability are realized at the same time.

The preparation method comprises the following steps: (1) taking a manganese source, an iron source, a phosphorus source and a lithium source according to the molar ratio of Mn: Fe: P: Li = x: (1-x): 1: (1.0-1.1), x is more than or equal to 0.3 and less than or equal to 0.7, and taking 15-25% of a carbon source according to the mass of the product lithium manganese iron phosphate; the lithium source comprises a first lithium source and a second lithium source, and the melting point of the first lithium source is lower than that of the second lithium source; (2) grinding and mixing the manganese source, the iron source, the phosphorus source, the first phosphorus source and half of the carbon source, drying, and carrying out a first sintering reaction at a temperature higher than the melting point of the first lithium source and lower than a second sintering reaction temperature to obtain a sintered material; and (3) grinding and mixing the sintered material, a second lithium source and the remaining half part of the carbon source, drying, and carrying out a second sintering reaction to obtain the lithium manganese iron phosphate positive electrode material at a second sintering temperature lower than the melting point of the second lithium source. According to the method, lithium sources with different melting points are added in batches, the sintering temperature is controlled, lithium manganese iron phosphate phases are sequentially generated and mutually restricted, the particle size difference is formed, and the compaction density and capacity are improved.

A preparation method for a lithium manganese iron phosphate positive electrode material, comprising the following steps: (1) uniformly stirring an iron source, a phosphorus source, a lithium source and a dispersing agent in water, adding a manganese source, and uniformly mixing same to obtain a precursor pre-slurry; and (2) adjusting the solid content of the precursor pre-slurry to reach a target solid content A, the target solid content A satisfying 30 wt% ≤ A ≤ 60 wt%; (3) carrying out primary grinding treatment on the precursor slurry obtained in step (2); and (4) adding an organic phosphine scale and corrosion inhibitor to the precursor slurry, dissolving same, then drying the obtained slurry, and performing sintering and crushing to obtain the lithium manganese iron phosphate positive electrode material. Also provided is a positive electrode material prepared by the method.

According to the impurity removal method for the ferrophosphorus slag, impurities such as Al, Cu, Ti, carbon and organic electrolyte in the ferrophosphorus slag can be effectively removed through the method. The method comprises the following steps: (1) carrying out high-temperature calcination on ferrophosphorus slag A and chloride under a reduction condition to obtain ferrophosphorus slag B; (2) leaching the ferrophosphorus slag B to obtain ferrophosphorus liquid A and filter slag A; (3) adding sodium fluoride into the ferrophosphorus liquid A to obtain ferrophosphorus liquid B and filter residues B; and (4) adding iron powder into the ferrophosphorus liquid B, and carrying out solid-liquid separation to obtain the high-purity ferrophosphorus liquid. Meanwhile, the invention provides a method for preparing a ferromanganese phosphate precursor and an iron phosphate precursor by adopting the high-purity ferrophosphorus liquid obtained by the method.

The invention provides a lithium manganese iron phosphate precursor hydrate which comprises a mixture of manganese phosphorus ore phase manganese manganese phosphate and ammonium manganese iron phosphate, and the molar ratio of the manganese phosphorus ore phase manganese manganese phosphate to the ammonium manganese iron phosphate is (1: 9)-(1: 1). A precursor material obtained by roasting the precursor hydrate is uniform in manganese and iron element distribution and good in processability, and lithium manganese iron phosphate with relatively high compaction density, relatively high capacity and better comprehensive performance can be prepared. The invention also provides a preparation method of the lithium iron manganese phosphate precursor hydrate, a lithium iron manganese phosphate precursor, lithium iron manganese phosphate and a secondary battery.

The invention discloses a metal composite lithium iron phosphate solid-phase deposition coated lithium manganese iron phosphate positive electrode material and a preparation method thereof, and belongs to the technical field of lithium ion battery positive electrode materials. The preparation method of the metal composite lithium iron phosphate solid-phase deposition coated lithium iron manganese phosphate positive electrode material comprises the following steps: S1, preparing a lithium iron manganese phosphate material and sintering; s2, grinding lithium iron phosphate into nano particles, and mixing the nano particles with a sugar source to form lithium iron phosphate nano slurry; s3, transferring into a CVD (Chemical Vapor Deposition) fluidized bed in the lithium manganese iron phosphate cooling and sintering stage, spraying lithium iron phosphate nano slurry, gasifying and drying the lithium iron phosphate material, and coating the surface of the lithium manganese iron phosphate with the lithium iron phosphate material through solid-phase deposition; and S4, carrying out composite coating of carbon and metal oxide on the lithium manganese iron phosphate coated with the lithium iron phosphate to obtain the lithium manganese iron phosphate coated with the lithium iron phosphate. According to the invention, the problem of poor uniformity of lithium iron phosphate coated lithium iron manganese phosphate is solved, the electrical property of lithium iron manganese phosphate is improved, the ferromanganese dissolution is improved, and the cycle performance is improved.

The invention discloses a carbon-loaded high-entropy oxide and a preparation method thereof, the carbon-loaded high-entropy oxide is of a core-shell structure formed by coating carbon with a high-entropy oxide, and the high-entropy oxide comprises at least five metal elements of chromium, manganese, iron, cobalt, nickel and copper. The carbon-loaded high-entropy oxide has the advantages of low density, high dielectric loss and excellent wave-absorbing performance, and is expected to be widely applied to electromagnetic absorption and elimination in the fields of electronics, communication civil affairs and aerospace military.

The invention discloses a high-compaction lithium manganese iron phosphate material as well as a preparation method and application thereof. The preparation method comprises the following steps: firstly, respectively preparing large-particle-size ferromanganese phosphate and small-particle-size ferromanganese phosphate through an oxidation-reduction reaction, then compounding the large-particle-size ferromanganese phosphate and the small-particle-size ferromanganese phosphate to serve as a precursor for synthesizing the lithium ferromanganese phosphate, and reacting the precursor with raw materials such as a lithium source to prepare the lithium ferromanganese phosphate. The two precursors with specific particle sizes are compounded, so that the small-particle-size precursor can effectively fill gaps of the large-particle-size precursor, the compaction density of the lithium manganese iron phosphate product is further improved, and meanwhile, excellent electrical properties can be realized.

The invention belongs to the technical field of magnetite beneficiation, and particularly relates to a method for removing iron impurities in minerals through manual and automatic three-stage combination in magnet beneficiation, a three-stage iron removal system is arranged, the iron impurities and ferromanganese are detected step by step according to the size of the iron impurities and the property of magnets or ferromanganese, and a detected magnetic field is cooperatively calibrated step by step; and iron impurities in the ores are removed in a classified manner. Compared with the prior art, the system has the beneficial effects that a manual and automatic three-stage combined iron removal solution is adopted, large magnetic iron impurities, small magnetic iron impurities and ferromanganese impurities in the process are efficiently classified and removed in a targeted manner, damage of the iron impurities to equipment such as an ore crusher and a belt conveyor is avoided, the operation efficiency of the process is improved, and the production cost is reduced. And the problem of removing iron impurities in magnet beneficiation is solved.

The invention provides an iron manganese phosphate precursor and a preparation method thereof, a lithium iron manganese phosphate positive electrode material and a preparation method thereof, a lithium ion battery and electric equipment, and relates to the technical field of new energy. The ferromanganese phosphate precursor provided by the invention comprises secondary particles composed of a plurality of primary particles, the primary particles are nano dotted particles, the diameter of the primary particles is 20-300nm, the secondary particles are of a blocky structure, and the morphology of the ferromanganese phosphate precursor can improve the electrochemical performance and the compaction density of the material. According to the preparation method of the ferromanganese phosphate precursor provided by the invention, a salt solution is taken as a base solution, and a phosphorus source solution, an oxidizing agent and a pH regulator are jointly fed, so that uniform precipitation of Mn and Fe is realized; regulation and control of nucleation, growth process, crystallinity and dotted primary particle size are realized by regulating and controlling the reaction temperature, the adding rate of the oxidant and the phosphorus source and the reaction pH value.

The invention discloses a high-compaction-density ferromanganese phosphate precursor and a preparation method thereof, and belongs to the technical field of lithium batteries, and the provided preparation method comprises the following steps: step 1, respectively dissolving a manganese source, an iron source and a phosphorus source in water to form solutions; 2, adding a complexing agent into the iron source solution to form a complexing iron salt solution; step 3, mixing the complexing ferric salt solution, the manganese source solution and the phosphorus source solution, adding an oxidizing agent and alkali liquor, keeping the pH value of the system to be 5.5-8, heating and stirring for reaction, and synchronously introducing oxygen for bubbling during reaction; and 4, after the reaction is finished, carrying out solid-liquid separation, and drying and roasting to obtain the ferromanganese phosphate precursor. According to the method, under the action of the complexing agent, the homogeneity of iron-manganese coprecipitation is improved, oxygen is introduced for bubbling in the reaction process, and excessive growth of crystals is inhibited while the oxidation condition is ensured, so that the ferromanganese phosphate precursor is proper in particle size and uniform in distribution, and the positive electrode material prepared from the precursor has high compaction density and excellent electrochemical performance.

The present invention discloses a method for producing manganese monohydrogen phosphate trihydrate, a method for recycling Mn-containing mother liquor, and a cathode material, relating to the technical field of lithium-ion batteries. In the present invention, a solid manganese carbonate slurry is used as a bottom liquid to synthesize manganese monohydrogen phosphate. Through precipitation solid-phase transformation, an octahedral morphology feature is constructed, which has a larger specific surface area. During the subsequent synthesis of lithium iron manganese phosphate, it helps to improve the reactivity of Mn and form a more uniform lithium iron manganese phosphate cathode material, thereby improving the compaction capacity and electrochemical performance of the cathode material.

The invention discloses a preparation method of a multi-element doped ferromanganese oxide positive electrode precursor, and belongs to the technical field of lithium ion battery positive electrode material preparation. The molar ratio of manganese to iron in the multi-element doped ferromanganese oxide positive electrode precursor is x: (1-x), 0.2 lt; xlt; and the doping element accounts for 0.1-10% of the total mole number of manganese and iron. According to the multi-element doped ferromanganese oxide positive electrode precursor prepared by the invention, the coprecipitation intermediates are manganese carbonate and ferrous carbonate, and Ksp of the manganese carbonate and the ferrous carbonate are relatively close, so that the uniformity of ferromanganese can be ensured, meanwhile, metal ion doping is carried out in a liquid phase synthesis precursor stage, and the probability that doped ions enter compound lattices is greatly improved. The multi-element doped ferromanganese oxide positive electrode precursor has relatively high stability and good conductivity, and is beneficial to improving the capacity, the cycle life and the compaction density of a lithium iron manganese phosphate positive electrode material.

The invention relates to the technical field of electrode materials, and discloses a preparation method of a lithium iron manganese phosphate material and a lithium ion battery. The lithium iron manganese phosphate material is prepared by the following steps: performing in-situ growth in a cavity of polyethylene glycol-sucrose hybrid aerogel with a three-dimensional porous network structure to form a manganese iron phosphate precursor; the hybrid aerogel can control excessive agglomeration and disordered growth of ferromanganese phosphate precursor particles and avoid particle agglomeration, so that the finally formed lithium ferromanganese phosphate material particles are finer and more uniformly distributed, and an amorphous carbon-aluminum layer is formed during later calcination, so that the performance of the material is improved. The surface of lithium manganese iron phosphate particles is tightly coated with the composite material, electron transmission can be accelerated, particle pulverization can be reduced, meanwhile, corrosion of corrosive components in electrolyte can be inhibited, interface side reactions such as transition metal ion dissolution can be reduced, and finally the conductivity and cycling stability of the lithium ion battery are remarkably improved.

The invention provides a lithium manganese iron phosphate positive electrode material and a preparation method and application thereof. The method comprises the following steps: mixing manganese metal and iron metal, heating, melting and uniformly mixing in an inert gas atmosphere, and grinding into powder; adding an ammonium salt solution, continuously adding the ground manganese-iron alloy powder under heating to form a suspension, introducing compressed air and stirring, reacting, filtering, washing, drying, crushing and grinding to obtain a manganese-iron oxide precursor, feeding the manganese-iron oxide precursor, a lithium source, a phosphorus source and doped metal elements into pure water, adding a carbon source, mixing to form a suspension, and grinding and drying to obtain the lithium-phosphorus-doped manganese-iron composite material. And carrying out carbon thermal reduction in an inert gas atmosphere, and crushing to obtain the lithium manganese iron phosphate positive electrode material. The ferromanganese oxide precursor prepared by heating the metal manganese and the metal iron to a molten state and mixing the metal manganese and the metal iron realizes uniform dispersion of the manganese and the iron at an atomic level, avoids the problems of nonuniform mixing of the manganese and the iron and dissolution of the manganese, and improves the conductivity and the electrochemical performance of the material.

The application relates to a method for smelting high-manganese steel in a converter, and belongs to the technical field of steelmaking. The technical problem to be solved by the application is that the manganese content of end-point molten steel produced by a converter in the prior art is low. The technical solution provided by the application for solving the above technical problem is that carbon balls and high-carbon ferromanganese are added in stages according to oxygen supply amount in the smelting process of the converter, when the oxygen supply amount is within 0-10% and 10-80%, 30% and 70% of manganese alloy are respectively added; and when the oxygen supply amount is within 0-10%, 10-50%, 50-80% and 80-100%, 20%, 40%, 30% and 10% of carbonaceous raw materials are respectively added. Compared with the current process for producing high-manganese steel in a converter, the application reduces the investment of alloy heating furnaces and other equipment, meets the production requirements of more varieties of high-manganese steel, improves the metal yield of manganese, shortens the production cycle, and reduces the production cost of high-manganese steel.

The invention discloses a high-entropy doped manganese / iron-based layered material and a preparation method thereof, a pole piece and a battery, the material contains six different metal cations of manganese, iron, copper, titanium, lithium and magnesium in a transition metal layer, the material contains two different metal cations of sodium and calcium in a sodium layer, the chemical formula of the layered material is Na < 0.62 > Ca < 0.03 > Mn < 0.58 > Fe < 0.23 > Cu < 0.085 > Mg < 0.01 > Ti < 0.015 > Li < 0.08 > O < 2 >, the problem that the specific capacity is reduced and unstable in the prior art is solved.

The invention provides a modified biochar and ferromanganese double-metal hydroxide composite material and a preparation method thereof, and relates to the technical field of adsorption materials.The preparation method comprises the steps that straw is subjected to pyrolysis treatment, and biochar is obtained; and then loading the ferromanganese bimetal hydroxide on the surface of the biochar by using a chemical method. The preparation process comprises a plurality of steps of mixing, stirring, precipitating, washing, drying and the like, so that the ferromanganese double-metal hydroxide can be uniformly and firmly attached to the biochar; according to the scheme, the adsorption performance of the biochar (BC) and the catalytic performance of the ferromanganese bimetal hydroxide (MnFe-LDH) are combined, and the high removal efficiency on heavy metal ions and organic pollutants is achieved. In addition, the composite material also has good stability and renewability, and is beneficial to reducing the wastewater treatment cost and improving the treatment efficiency.

The invention belongs to the technical field of recycling of positive electrode materials of waste lithium ion batteries, and particularly discloses a method for quickly upgrading and regenerating lithium iron manganese phosphate by utilizing waste lithium iron phosphate powder. According to the method, the inherent characteristics of a leaching agent and an oxidizing agent are utilized, mechanical activation is combined with high-temperature sintering, and the waste lithium iron phosphate positive electrode active material is quickly regenerated into the lithium iron manganese phosphate material. Solid-liquid separation and impurity removal are not needed in the whole process, the obtained precursor can be directly used for preparing lithium manganese iron phosphate, compared with existing recycling, economic benefits can be improved to the maximum extent, influences on the environment can be reduced, and the additional value of recycled products is effectively improved.

The invention provides a preparation method of a lithium iron manganese phosphate positive electrode material, the positive electrode material and a lithium ion battery. The preparation method comprises the following steps: (1) sanding first slurry to obtain second slurry; and (2) carrying out spray drying and three-stage sintering on the second slurry to obtain the lithium iron manganese phosphate positive electrode material, the first slurry comprises a lithium source, a manganese source, an iron source, a phosphorus source and a solvent. According to the preparation method provided by the invention, the lithium manganese iron phosphate positive electrode material with wide distribution of large and small particles, high conductivity and high compaction density is obtained.

The invention relates to the field of material science and mechanical engineering, in particular to a high-strength aluminum-magnesium-silicon material bolt for a new energy automobile and a preparation method of the high-strength aluminum-magnesium-silicon material bolt. The bolt is made of an aluminum-magnesium-silicon alloy, and the alloy contains magnesium, silicon, manganese, iron, chromium, titanium, scandium, rare earth elements and the balance of aluminum. By optimizing the proportion of rare earth elements (yttrium, lanthanum and cerium) and scandium, grains are effectively refined, the tensile strength, the yield strength and the ductility are improved, and meanwhile the corrosion resistance and the fatigue resistance are enhanced. The preparation method comprises the steps that vacuum melting is combined with the ultrasonic-assisted technology, alloy elements are evenly distributed, and then the material structure is optimized through solution treatment at the temperature of 540 DEG C for 1.5 h and aging treatment at the temperature of 160 DEG C for 8 h. And the surface of the bolt is subjected to anodic oxidation and coated with a composite coating containing silicon dioxide nanoparticles, so that the wear resistance and the corrosion resistance are improved. Through verification, the bolt has the excellent performance that the tensile strength is larger than or equal to 490 MPa, the yield strength is larger than or equal to 440 MPa, the ductility is larger than or equal to 8.5%, and the salt spray test time is larger than or equal to 1500 hours, and the fastening requirement of the new energy automobile under the complex working condition is met.