NOVELTY - Recycling of desulfurized waste liquid of sulfate involves: desulfurization of waste liquid by completely using air after oxidation, depositing and removing impurities, entering into reaction kettle heating by concentrating, supersaturating, stopping heating, cooling to 60 degrees C, carrying out centrifugal dewatering, obtaining solid sulfate crystal and drying.    USE - For recycling of desulfurized waste liquid of sulfate (claimed) e.g. ammonium sulfate, magnesium sulfate as fertilizer.    ADVANTAGE - The method desulfurizes waste liquid provides as a flue gas waste heat as the heat source of waste water for treating and recovering ammonia desulfurization waste liquid, and used in desulfurizing system in the waste liquid without waste liquid discharge and protects the environment. The obtained recycled ammonium sulfate, magnesium sulfate can be used as fertilizer to improve comprehensive utilization value of the waste liquid, the device system is featured with simple structure and less investment.    DETAILED DESCRIPTION - Recycling of desulfurized waste liquid of sulfate involves: desulfurization of waste liquid by completely using air after oxidation, depositing and removing impurities, entering into reaction kettle heating by concentrating, supersaturating, stopping heating, cooling to 60 degrees C, carrying out centrifugal dewatering, obtaining solid sulfate crystal and drying. An INDEPENDENT CLAIM is included for a device system comprising reaction kettle (1), centrifugal machine (2), where reaction kettle is set smoke inlet (3), flue gas outlet (4), cooling water inlet (5) and a cooling water outlet (6), where the centrifuge (2) is connected with the reaction kettle which is connected with a pipeline; and further comprising collecting tank (7), where the reaction kettle, the centrifuge is connected with the collecting tank.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic diagram of device system.    Reaction kettle (1)    Centrifugal machine (2)    set smoke inlet (3)    Flue gas outlet (4)    Cooling water inlet (5)    Cooling water outlet (6)    Collecting tank (7)