A method for producing lithium manganese iron phosphate, the method comprising: obtaining first precursor particles by mixing metal powder containing iron and manganese with a phosphate compound, and stirring and pulverizing; obtaining second precursor particles by mixing the first precursor particles with a lithium source, and stirring and pulverizing; and calcining the second precursor particles to obtain lithium manganese iron phosphate.

The present solution provides a preparation method for a three-dimensional structured ferrous phosphate pigment with corrosion early warning capability, including following steps: preparing a ferrous ion-containing solution for providing ferrous ions, where the ferrous ion-containing solution includes a soluble ferrous salt and a surfactant but no oxidizing ions, and the ferrous ion-containing solution is maintained in an acidic environment; preparing an initial mixed solution for providing phosphate ions and ammonium ions; and performing ultrasonic refinement, heating, and holding on the intermediate mixed solution using an auxiliary device with ultrasonic oscillation and microwave heating functions to obtain a final mixed solution; and filtering out precipitates from the final mixed solution, and then transferring the precipitates to a vacuum environment for high-temperature heating treatment to obtain a three-dimensional structured ferrous phosphate pigment with corrosion early warning capability.

The present disclosure belongs to technical field of cathode materials of lithium batteries, and discloses a preparation method of high-safety high-capacity lithium manganese iron phosphate. The method includes the steps: (1) synthesizing a ferrous phosphate precursor through a co-precipitation process, and sintering to obtain an anhydrous ferrous phosphate precursor; (2) synthesizing a manganese phosphate precursor through co-precipitation process, and sintering to obtain an anhydrous manganese phosphate precursor; (3) adding lithium phosphate and deionized water into anhydrous ferrous phosphate precursor, and performing ball milling and wet sanding to obtain slurry A; (4) adding lithium phosphate, an organic carbon source, a dispersant, a dopant and deionized water into anhydrous manganese phosphate precursor, and performing ball milling and wet sanding to obtain slurry B; and (5) mixing slurry A with slurry B, and performing ball milling, spray drying, sintering and air jet pulverization to obtain high-safety high-capacity lithium manganese iron phosphate.

A process for enriching phosphorus and recovering vivianite by a biofilm method includes the following steps: 1) an aerobic phosphorus absorption stage; 2) an anaerobic phosphorus release stage; 3) a cyclic enrichment stage; 4) a seed crystal forming stage; and 5) a crystal forming stage. Phosphorus is enriched by the biofilm method and recovered with vivianite as a recovery product, which solves the problem of phosphorus removal from municipal sewage and improves the economic value; by preparing high dissolved oxygen at the aerobic stage, a high-concentration phosphorus recovery solution can be obtained with a relatively low carbon-phosphorus ratio and relatively high enrichment times, and the consumption of carbon sources can be reduced; since the oxidation-reduction potential is controlled to be less than 100 mv by the biofilm method at the anaerobic phosphorus release stage, the oxidation-reduction potential does not need to be adjusted again during the recovery of vivianite.

In one aspect, a sheet shaped ferric phosphate with a high iron-to-phosphorus ratio has a sheet shaped structure with an iron-to-phosphorus (Fe/P) ratio greater than 0.99, a ratio of length to width to thickness of the sheet shaped structure is (105 to 130):(90 to 100):(10 to 12), 3.5 m.sup.2/ga specific surface area of the sheet shaped structure6.5 m.sup.2/g, and a particle size of the sheet shaped structure<35 m.

A method of manufacturing a positive cathode material with a stable olivine structure, including forming a mixture by combining lithium precursors, iron precursors, and phosphate precursors in an aqueous solution. The method further includes adding two different carbon sources to the mixture during mixing process and evaporating water from the mixture to form a homogeneous precursor mixture. The method further includes annealing the homogeneous precursor mixture to form a carbon-coated lithium iron phosphate cathode material with the stable olivine structure. The use of two different carbon sources in obtaining the carbon coating over lithium-iron-phosphate cathode material in an amorphous form, enhances the stability and performance of the cathode material resulting in an enhanced performance and longevity of rechargeable lithium-iron-phosphate batteries.

Provided is a method for producing an intermediate product of an electrode. The method for producing an intermediate product of an electrode may comprise the steps of: preparing a base particle; forming a coating layer, comprising a first metal, on the surface of the base particle by mixing the base particle with a coating source which comprises the first metal; and forming a molten source, in which is melted a second metal and the base particle on which the coating layer is formed, by heat-treating the second metal and the base particle on which the coating layer is formed.

Provided are a phosphate material with a nanoporous structure, a preparation method therefor and a use thereof. It has a chemical formula of Mn.sub.1-xFe.sub.xPO.sub.4, (0.01x0.99) and has a particle size of at most 50 nm and a porous structure. Also provided is a phosphate material having a general chemical formula of Mn.sub.1-a-bFe.sub.aM.sub.bPO.sub.4, wherein M is one or more selected from the group consisting of Mg, Ti, V, Cr, Co, Ni, Zn, Ga, Al, Zr, Nb, Mo, Sn, Sb, Ca, Ba, Sr, B, Ru, Si, Te, Nb, Cu and Li, and preferably a combination of five or more of the elements, 0.01a0.98, 10.sup.4b10.sup.2, and the phosphate material has a particle size of at least 50 nm and has a porous structure. The material can be used for preparing a manganese iron phosphate battery cathode material, and the specific capacity, rate performance and cycle performance of the obtained anode material are improved.

A method of preparing ferric phosphate from iron-containing waste, including: step a) providing a ferric chloride-containing mixture solution obtained from acidolysis of iron-containing waste; step b) adjusting pH of the ferric chloride-containing mixture solution to satisfy 0<pH2 and Fe.sup.3+ concentration to 10-80 g/L with an alkaline compound and water, to obtain an iron source solution; step c) mixing and reacting the iron source solution obtained from the step b) with a solution of calcium dihydrogen phosphate in a molar ratio of P to Fe of 1:1-1.8, to obtain a slurry with a pH of 0.2-2; and step d) performing aging and crystal transformation on the slurry, to obtain ferric phosphate. A battery-grade ferric phosphate with high purity and good product quality can be obtained without the need for deep purification of raw materials.

Provided are a dehydration method and a dehydration device of an iron phosphate hydrate. The dehydration method includes the following steps: subjecting the iron phosphate hydrate to microwave irradiation dehydration to obtain an anhydrous iron phosphate. The dehydration device includes a microwave heating assembly, a heat receiving assembly, and a transmission assembly; wherein the microwave heating assembly includes a microwave generator and a microwave heater connected to the microwave generator; the heat receiving assembly includes an open material storage device, and the open material storage device is made from a material that is not magnetic substances; and the transmission assembly includes a conveyor belt, and the open material storage device is arranged on a surface of the conveyor belt.