Method for solid-liquid separation of waste incineration fly ash water washing slurry

The invention discloses a method for solid-liquid separation of a waste incineration fly ash water washing slurry. The method comprises the following steps: 1, adding water to waste incineration fly ash to be processed, and carrying out stirring water washing to obtain a primary fly ash water washing slurry to be processed by adopting two horizontal screw discharge decanter centrifuges; 2, carrying out primary centrifuge separation on the primary fly ash water washing slurry by adopting a first horizontal screw discharge decanter centrifuge to obtain solid fly ash and a secondary fly ash water washing slurry; 3, simultaneously pumping a flocculating agent and the secondary fly ash water washing slurry into a second horizontal screw discharge decanter centrifuge; and 4, carrying out secondary centrifuge separation on the flocculated secondary fly ash water washing slurry by adopting a second horizontal screw discharge decanter centrifuge to obtain a solid phase and a liquid phase. The method can effectively remove salt substances in the waste incineration fly ash water washing slurry, and controls the fly ash loss amount of the waste incineration fly ash water washing slurry in an allowed loss amount range.