Method for deep desiliconization of coal ash and recovery of silicon resources

Abstract

A method for deep desiliconization of coal ash and recovery of silicon resources includes: ball-milling and drying decarburized coal ash; adding calcium oxide into a salt to obtain a mixture, and heating the mixture to a molten state under an inert atmosphere to obtain a molten salt, a molar ratio of the calcium oxide to the salt ranging from 0.5% to 18%; placing the ball-milled and dried coal ash into the molten salt, performing reaction under an atmospheric pressure, separating a reaction product from the molten salt, cooling the separated reaction product under an inert atmosphere, washing the cooled reaction product and drying the washed reaction product to obtain desiliconized coal ash; and cooling the molten salt under an inert atmosphere, washing the cooled salt and filtering the washed salt to recover calcium silicate and a filtrate.

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