The boiler dust removal equipment using a certain concentration (here to 28% as an example) of ammonia as a desulfurization agent, the production of ammonia sulfate slurry, transported to the fertilizer plant treatment system. Ammonia required for ammonia desulfurization,By the preset PH control valve to automatically adjust, and by the flow meter to measure. Ammonium sulfate crystal in the desulfurization and dust catcher in the saturated ammonium sulfate slurry crystal, to generate 35% weight ratio of suspended particles.The slurry pump is sent to the processing field, after primary and two stage dehydration, and then, and then sent to the fertilizer plant for further dehydration, drying, condensation and storage, through the boiler dust removal equipment for flue gas desulfurization at the same time,