This method recycles iron phosphate slag, which is produced as waste during lithium iron phosphate battery recycling processes that contain leaching or crushing for the sole extraction of lithium. This method extracts aluminum phosphate, iron phosphate, and lithium phosphate from the waste slag. The recycling process comprises these steps: (a) extraction of aluminum phosphate through addition of sodium hydroxide; (b) removal of carbon additives, graphite and other organic compounds through solvation of solely lithium, iron, and phosphate compounds through addition of sulfuric acid; (c) precipitation of iron phosphate by addition of hydrogen peroxide; (d) extraction of lithium phosphate from the mother liquor; (e) recycling of mother liquor into water and sodium sulfate. This process wastes few chemicals while still having a high reclamation efficiency in terms of purity and quantity. Furthermore, due to its relatively low costs, the profit margin of this process is very good.

The present disclosure relates to the technical field of ferric phosphate, in particular to a process and a system for preparing ferric phosphate by mixing and stirring in a reactor with external circulation. Disclosed is a process for preparing ferric phosphate by mixing and stirring in a reactor with external circulation, comprising the following steps: adding a ferric salt solution, a monoammonium phosphate solution, and a protective agent into the reactor, and subjecting the resulting mixed liquid to a preliminary reaction at 90-100? C.; after the completion of the preliminary reaction, carrying out an external circulation reaction at 85-90? C. The process described in the present disclosure has a high reaction speed, and the obtained ferric phosphate has a high yield and low content of impurity in the ferric phosphate.

A preparation method of battery composite material includes steps of providing a manganese-contained compound, phosphoric acid, a lithium-contained compound, a carbon source, and deionized water; processing a reaction of the manganese-contained compound, the phosphoric acid, and a portion of the deionized water to produce a first product; placing the first product at a first temperature for at least a first time period to produce a first precursor, wherein the chemical formula of the first precursor is written by Mn.sub.5(HPO.sub.4).sub.2(PO.sub.4).sub.2(H.sub.2O).sub.4; and processing a reaction of at least the first precursor, the lithium-contained compound, and another portion of the deionized water, adding the carbon source, and then calcining to produce battery composite material. Therefore, the preparation time is shortened, the energy consuming is reduced, the phase forming of the precursor is more stable, and the advantages of reducing the cost of preparation and enhancing the quality of products are achieved.

The present invention discloses a preparation method for iron phosphate powder by microporous filtration and concentration and a preparation device thereof. The preparation method includes: putting raw materials into a reactor to react for nucleation, a mother liquor generated after raw materials reaction entering the filter concentrator, and controlling and starting a stirring shaft for driving an upper stirring blade and a lower stirring blade to rotate for grinding and scaling; when a mother solution level exceeds an upper liquid inlet end of lower microporous filtration tube groups, controlling and starting a filtrate valve of a filtrate tube of the lower microporous filtration tube groups, and when the mother solution level exceeds the upper liquid inlet end of upper microporous filtration tube groups, controlling and starting a filtrate valve of a filtrate tube of the upper microporous filtration tube groups. The present invention has small instantaneous flow fluctuation, has the characteristic of good accuracy of a reaction system, and integrates a filtration system and an intermediate tank to effectively reduce the volume and shorten the reaction process.

The present invention relates to the field of lithium battery material preparation technologies, particularly to a method for preparing lithium iron phosphate using the by-product ferrous sulfate from titanium dioxide. The method comprises the following steps: dissolving by-product ferrous sulfate from titanium dioxide in acidic aqueous solution, stirring with iron powder for reaction; adding iron phosphate or lithium iron phosphate waste powder to the solution, heating and stirring the mixture, allowing the mixture to settle and cool, and filtering the cooled mixture to obtain a purified ferrous sulfate solution; and adding phosphoric acid and a lithium hydroxide solution in an autoclave, and finally adding the purified ferrous sulfate solution, heating the mixture under stirring, then filtering, washing, and drying the mixture to obtain lithium iron phosphate powder; Using it as an iron source to prepare positive electrode materials for lithium-ion batteries has excellent electrochemical performance.

The invention relates to a method of recycling lithium iron phosphate batteries with the aim of enabling the isolated recovery of elements from black mass. Black mass comprising at least cathodic and anodic components is immersed in a pH 13-14 solution to obtain a first leachate and first solid residue. The first leachate is immersed in a 4-6M acid solution to obtain a second leachate. The second leachate is passed through a first ion-exchange column where fluoride ions are retained and a second ion-exchange column where copper ions are to obtain a second eluate. The pH of the second eluate is adjusted to about 2.5-5 and a quantity of phosphoric acid that is sufficient to achieve an equivalent stoichiometric ratio of ferric iron and phosphate anions is added to obtain a first solution and an iron (III) phosphate precipitate. The first solution is combined with the first leachate to obtain a second solution. The pH of the second solution is adjusted to about 6.5 to a residual precipitate and a lithium solution.

The present invention provides a cost-effective method of synthesizing phosphate salt of a metal such as Fe and Mn that can be used for electrode active material of a lithium secondary battery. A precipitation reaction is first carried out to produce a solid salt of the metal having a lower valence value, e.g. Fe(II) and Mn(II). The solid salt is then purified before it is oxidized to form the target phosphate salt of the metal having a higher valence value, e.g. Fe(III) and Mn(III). The invention exhibits numerous technical merits such as easier operation, higher purity, and less consumption of washing water, among others.

The present disclosure provides a method and a system for efficient and selective recovery of a ferric phosphate product from a leachate. The method includes the following steps: adjusting a pH value of a phosphorus-containing leachate to obtain an acidic phosphorus-containing leachate, heating the acidic phosphorus-containing leachate, adding an iron salt to precipitate a phosphorus element in the acidic phosphorus-containing leachate in the form of a ferric phosphate hydrate, and recovering an obtained ferric phosphate hydrate precipitate. In the present disclosure, production of a phosphorus product requires a certain amount of iron element added into the leachate. Iron widely distributed on the earth is low in cost and easily available, thereby facilitating large-scale applications of the method. An initial leachate after acid leaching shows acidic, and only a slight pH adjustment is required to achieve a target pH value of the leachate.

Methods of producing cathode material precursors from metal carbonyl complexes are described.

A method for production of phosphate compounds comprises dissolving of a raw material comprising phosphorus, aluminium and iron, in a mineral acid. Insoluble residues from the dissolving step are separated. Iron hydroxide is added causing precipitation of phosphate compounds. The precipitated phosphate compounds are removed. The phosphate compounds are dissolved by an alkaline solution. Iron hydroxide is filtered out. Lime is added, causing precipitation of calcium phosphate. The precipitated calcium phosphate is separated. The leach solution after the separating of precipitated calcium phosphate is recycled to be used for dissolving phosphate compounds by an alkaline solution.