In one aspect, a preparation method for ferric phosphate includes the following steps: (a) feeding a ferrous sulfate solution and a phosphate solution including hydrogen peroxide simultaneously into a first reactor for mixing and reacting to obtain nucleated ferric phosphate; wherein a molar ratio of iron element to phosphorus element in the feeding process is 1:1, and a stirring speed is 500-600 r/min; (b) discharging the nucleated ferric phosphate to a second reactor for growth to obtain amorphous ferric phosphate slurry, and post-processing the amorphous ferric phosphate slurry to obtain the high tap density ferric phosphate; wherein a stirring speed is 120-150 r/min. The first reactor is a small-volume reactor, and the second reactor is a large-volume reactor.

In one aspect, the disclosure relates to system for recovering ammonia and phosphorus from a waste stream, methods of using the system to precipitate phosphorus as vivianite and to separate ammonia from total organic carbon in the waste stream, methods of modifying a nanofiltration membrane to exhibit selectivity for ammonia passage relative to total organic carbon passage, and compositions including fertilizers produced using recovered ammonia, phosphorus, and optionally potassium from the waste stream. This abstract is intended as a scanning tool for purposes of searching in the particular art and is not intended to be limiting of the present disclosure.

In one aspect, a preparation method of iron phosphate includes: mixing pyrite cinder and an sulfite evenly in water to obtain a first mixed system; adding phosphoric acid and a buffer to the first mixed system to perform a leaching reaction; performing a first solid-liquid separation on a slurry obtained from the leaching reaction to obtain a first filtrate and a first residue; introducing air into the first filtrate and then performing a first stirring reaction on the first filtrate; performing a second solid-liquid separation on a slurry obtained from the first stirring reaction to obtain a second filtrate and a second residue; and calcining the second residue to obtain iron phosphate.

An LFP electrode material is provided which has improved impedance, power during cold cranking, rate capacity retention, charge transfer resistance over the current LFP based cathode materials. The electrode material comprises crystalline primary particles and secondary particles, where the primary particle is formed from a plate-shaped single-phase spheniscidite precursor and a lithium source. The LFP includes an LFP phase behavior where the LFP phase behavior includes an extended solid-solution range.

A process for producing a phosphate by: introducing oxidic metal(II)-, metal(III)- metal(IV) or compounds with mixed oxide stages selected from hydroxides, oxides, oxide-hydroxides, oxide-hydrates, carbonates and hydroxide carbonates, of at least one of the metals Mn, Fe, Co and Ni with the elemental forms or alloys of at least one of the metals Mn, Fe, Co and/or Ni into an aqueous medium containing phosphoric acid, and reacting the oxidic metal compounds with elemental forms or alloys of the metals to obtain divalent metal ions, removing solid substances, producing an alkali metal phosphate receiver solution with a pH-value of 5 to 8 and metering the aqueous solution into the receiver solution and at the same time metering a basic aqueous alkali hydroxide solution that the pH-value of the resulting reaction mixture is kept in the region of 5 to 8 to precipitate the desired phosphate.

The present invention relates to a method for recycling LiFePO.sub.4, which is an olivine-based cathode material for a lithium secondary battery. The present invention is characterized in that a cathode material including LiFePO.sub.4 is synthesized using, as precursors, amorphous FePO.sub.4.XH.sub.2O and crystalline FePO.sub.4.2H.sub.2O (metastrengite) obtained by chemically treating LiFePO.sub.4 as an olivine-based cathode material for a lithium secondary battery, which is produced from a waste battery. Since a cathode fabricated from the LiFePO.sub.4 cathode material synthesized according to the present invention does not deteriorate the capacity, output characteristics, cycle efficiency and performance of the secondary battery and the cathode material of the lithium secondary battery may be recycled, the secondary battery is economically efficient.

A process for the preparation of carbon-coated lithium transition metal phosphate having the formula Li.sub.0.9+xM.sub.yMn.sub.1yPO.sub.4 and its use as cathode material in secondary lithium-ion batteries wherein the process includes few synthesis steps which can be conducted easily, therefore providing a low cost process and results in a complete reaction of the starting material compounds or the mixtures thereof. At least one starting material compound is dispersed or dissolved in an essentially aqueous medium and heated to a temperature between 50 C. and 100 C. prior to addition of the remaining starting material compounds.

A regular octahedral iron phosphate, a preparation method thereof, a lithium iron phosphate cathode material, and a lithium iron phosphate battery are disclosed. The method for preparing the regular octahedral iron phosphate includes: obtaining a mixed solution A containing a phosphate and a ferrous salt, in which, the mixed solution A is an acidic solution; mixing the mixed solution A with an oxidant, during which, ferrous ions in the mixed solution A are oxidized into ferric ions, whereby obtaining a slurry A; mixing the slurry A with a phosphoric acid solution and enabling reaction under a heating condition, whereby obtaining a slurry B; and subjecting the slurry B to solid-liquid separation treatment, washing treatment, drying treatment, and calcination treatment, whereby obtaining the regular octahedral iron phosphate.

The present disclosure relates to a method for preparing ferroboron alloy-coated lithium iron phosphate, comprising: preparing ferrous phosphate and lithium phosphate, then mixing ferrous phosphate and lithium phosphate and adding a hydrazine hydrate solution to obtain a mixture which is then subjected to grinding, drying and then calcining to obtain a calcined material, adding pure water to the calcined material and grinding the calcined material in water to obtain a slurry, to which PEG, ferrous sulfate crystals and disodium EDTA are added and stirred to dissolve, then adding a sodium borohydride solution and a sodium hydroxide solution while stirring and maintaining a pH in the process at 8.5-10.5, reacting for 15-30 min to obtain a product, and filtering, washing and vacuum drying the product to obtain the ferroboron alloy-coated lithium iron phosphate. The method may reduce interface resistance while improving conductivity, corrosion resistance, oxidation resistance and density of the product.

The present application discloses a method for preparing ferric phosphate, including the following steps: mixing a surfactant with a first metal liquid containing iron and phosphorus elements, adding with adding seed crystal, aging under heating and stirring, filtering the aged solution to obtain a filter residue, and drying and sintering the filter residue, thereby obtaining the ferric phosphate; the seed crystal is ferric phosphate dihydrate or basic ammonium ferric phosphate. In the present application, the surfactant is used for modification of the seed crystal, secondary crystal nucleus is generated, which induces the formation of the basic framework of the product particles. Through the aging process, the deposition of the crystal nucleus on the surface of the seed crystal makes the framework of the crystal grain more complete, so that the primary particles are arranged more densely and orderly and tend to constitute spherical secondary particles.