Method for separating and purifying soluble chlorine salt by washing fly ash with water

The invention discloses a method for separating and purifying soluble chlorine salt by washing fly ash with water, which belongs to the technical field of industrial waste salt treatment. The method comprises the following steps of evaporating and crystallizing fly ash washing brine, separating out calcium chloride, and carrying out solid-liquid separation to obtain mother liquor 1 and calcium chloride dihydrate, removing moisture from the mother liquor 1 to obtain carnallite, mixing carnallite and an alcohol solvent, leaching, and filtering to obtain filter residues and mother liquor 2, distilling the mother liquor 2 to recover methanol to obtain calcium chloride, mixing the filter residue with dilute sulphuric acid, reacting, collecting hydrogen chloride gas in the reaction process, evaporating and crystallizing reaction liquid after the reaction is finished, and separating to obtain potassium sulfate and mixed liquid, freezing and crystallizing the mixed solution, and separating to obtain sodium sulfate de