A process for the isolation and purification of substantially pure chemicals, including silica gel, sodium silicate, aluminum silicate, iron oxide, and rare earth elements (or rare earth metals, REEs), from massive industrial waste coal ash including a plurality of caustic extractions of coal ash at an elevated temperature, followed by an acidic treatment to dissolve aluminum silicate and REEs. Dissolved aluminum silicate is precipitated out by pH adjustment as a solid product while REEs remain in the solution. REEs are captured and enriched using an ion exchange column. Alternatively, the solution containing aluminum silicate and REEs is heated to produce silica gel, which is separated from the enriched REEs solution. REEs are then isolated and purified from the enriched solution to afford substantially pure individual REE by a ligand-assisted chromatography.

A process for the isolation and purification of substantially pure chemicals, including silica gel, sodium silicate, aluminum silicate, iron oxide, and rare earth elements (or rare earth metals, REEs), from massive industrial waste coal ash including a plurality of caustic extractions of coal ash at an elevated temperature, followed by an acidic treatment to dissolve aluminum silicate and REEs. Dissolved aluminum silicate is precipitated out by pH adjustment as a solid product while REEs remain in the solution. REEs are captured and enriched using an ion exchange column. Alternatively, the solution containing aluminum silicate and REEs is heated to produce silica gel, which is separated from the enriched REEs solution. REEs are then isolated and purified from the enriched solution to afford substantially pure individual REE by a ligand-assisted chromatography.

The current invention concerns a method for increasing an iron content of a solution by converting low iron containing solutions into highly concentrated ferric chloride solutions by adding iron containing substances. The invention concerns also methods for transporting and storage of said highly concentrated ferric chloride solutions.

The current invention concerns a method for increasing an iron content of a solution by converting low iron containing solutions into highly concentrated ferric chloride solutions by adding iron containing substances. The invention concerns also methods for transporting and storage of said highly concentrated ferric chloride solutions.

The invention relates to a method and system for phosphate recovery from a stream such as waste flow, sewage or another sludge stream. The method comprises the steps of: providing an incoming stream comprising an initial amount of phosphate; dosing/controlling iron salt to the stream such that precipitates are formed in the stream, wherein the precipitates comprise vivianite like structures comprising more than 60% of the initial amount of phosphate in the incoming stream, and preferably also the steps of: separating the vivianite like structures from the stream; and recovering the phosphates from the separated vivianite like structures.

The invention relates to a method and system for phosphate recovery from a stream such as waste flow, sewage or another sludge stream. The method comprises the steps of: providing an incoming stream comprising an initial amount of phosphate; dosing/controlling iron salt to the stream such that precipitates are formed in the stream, wherein the precipitates comprise vivianite like structures comprising more than 60% of the initial amount of phosphate in the incoming stream, and preferably also the steps of: separating the vivianite like structures from the stream; and recovering the phosphates from the separated vivianite like structures.

An intercalation agent for rapid graphite exfoliation in mass production of high-quality graphene is provided, including a transition metal halide salt, a nitrogen source substance and an organic solvent, and the mass ratio of the transition metal halide salt, the nitrogen source substance and the organic solvent is (1-10):1:(2-10). The transition metal halide salt can form a eutectic with the nitrogen source substance or the organic solvent, and the melting point thereof is lower than that of each component, thereby lowering the reaction temperature, and the preparation cost and difficulty; and a hydrogen bond can also be formed between the nitrogen source substance and the organic solvent, thereby avoiding interlayer stacking of the prepared graphene, thus improving the exfoliation efficiency and the product quality.

An intercalation agent for rapid graphite exfoliation in mass production of high-quality graphene is provided, including a transition metal halide salt, a nitrogen source substance and an organic solvent, and the mass ratio of the transition metal halide salt, the nitrogen source substance and the organic solvent is (1-10):1:(2-10). The transition metal halide salt can form a eutectic with the nitrogen source substance or the organic solvent, and the melting point thereof is lower than that of each component, thereby lowering the reaction temperature, and the preparation cost and difficulty; and a hydrogen bond can also be formed between the nitrogen source substance and the organic solvent, thereby avoiding interlayer stacking of the prepared graphene, thus improving the exfoliation efficiency and the product quality.

Provided is a method for preparing graphene by liquid-phase ball milling exfoliation, including following steps: mixing a transition metal halide salt, a nitrogen source substance and an organic solvent to prepare an intercalation agent; mixing the intercalation agent with graphite, carrying out ball milling, and then performing centrifugation to obtain a graphite intercalation compound; washing and filtering the graphite intercalation compound obtained, adding an expansion agent, and carrying out ultrasonic agitation to obtain a graphene dispersion; and washing, filtering and drying the graphene dispersion to obtain graphene powder.

The invention relates to a method for producing a metal chalcogenide thin film electrode, comprising the steps: (a) contacting a metal or metal oxide with an elementary halogen in a non-aqueous solvent, producing a metal halide compound in the solution, (b) applying a negative electric voltage to an electrically conducting or semiconducting substrate which is in contact with the solution from step (a), and (c) during and/or after step (b) contacting the substrate with an elementary chalcogen forming a metal chalcogenide layer on the substrate. The invention also relates to a metal chalcogenide thin film electrode which can be produced by the method and its use as an anode for releasing oxygen during (photo)electrochemical water splitting.