Method for ensuring up-to-standard emission of chlorine in discharged flue gas in comprehensive utilization process of aluminum ash

The invention discloses a method for ensuring up-to-standard emission of chlorine in discharged flue gas in a comprehensive utilization process of aluminum ash, which comprises the following steps: conveying aluminum ash dissolved slurry to a filter for liquid-solid separation, conveying filtrate into a filtrate tank, conveying the filtrate into an evaporation stock solution tank of an aluminum oxide production system by using a pump, washing a filter cake, conveying the washed filter cake into a raw slurry blending tank, mixing the above with alkali and lime according to a certain alkali ratio and calcium ratio to obtain qualified raw slurry, sending the qualified raw slurry to a firing kiln for clinker sintering, sending the sintered clinker to an alumina system after entering a clinker dissolution process for dissolution, and discharging flue gas of the firing kiln after dust collection. After the filter cake of the slurry dissolved out of the aluminum ash is washed, chloride ions in attached liquid of the