Method for preparing ammonium fluosilicate by utilizing tail gas containing fluorine in phosphatic fertilizer production

The invention relates to a method for preparing ammonium fluosilicate by utilizing tail gas containing fluorine in phosphatic fertilizer production. Ammonium fluosilicate crystal mother solution is taken as cleaning solution to absorb tail gas containing fluorine of phosphatic fertilizer, so as to obtain high concentration rich liquor, then ammonium is used for neutralization and filtration, filtrate is cooled and is separated out ammonium fluosilicate crystal, liquid-solid separation is carried out to obtain ammonium fluosilicate crystal mother solution and ammonium fluosilicate solid product, the ammonium fluosilicate crystal mother solution is returned to the phosphatic fertilizer absorption system to be taken as cleaning solution, so as to recycle and absorb the tail gas containing fluorine, and the steps are repeated. The invention utilizes the existing phosphatic fertilizer absorption system to cause the ammonium fluosilicate crystal mother solution to be transformed into rich liquor containing fluorine