Method and device for manufacturing granular chemical fertilizer by utilizing secondary guniting

The invention belongs to the technical field related to granular fertilizer production, and provides a method for producing a granular fertilizer by using secondary guniting, which comprises the following steps: preparing a powdery raw material ammonium sulfate required by the fertilizer; pouring all the raw materials, namely ammonium sulfate, into a No.1 dryer for primary drying to prepare a solid fertilizer; pouring the dried solid fertilizer into an extrusion granulator, and carrying out extrusion granulation on the fertilizer to prepare a granular fertilizer; the granulated fertilizer is placed on a first screening machine to be screened, and the granulated fertilizer with the preset specification is preliminarily screened out; putting the sieved granular fertilizer into a pulp shooting machine, and carrying out pulp shooting and film coating; the granulated fertilizer obtained after guniting and film coating is put into a second drying machine to be subjected to secondary drying; putting the dried and de