NOVELTY - Producing sulfur ammonium phosphate product by phosphorus slag sewage treatment technique, involving: (1) mixing, at the same time adding ammonium sulfate slurry, ammonium phosphate slurry and slag; (2) mixing pump to circulate liquid, heating slurry to 85-100 degrees C; (3) putting prepared slurry into pelleting/drying spray granulation, obtaining semi-finished product; and 4) drying semi-finished product, sieving, and cooling to obtain the product, crushing, sieving, pelleting/drying; and (5) using dust scrubber, washing, and removing dust.    USE - For producing sulfur ammonium phosphate product (claimed) used as fertilizer for grape, sugar cane, radish and other crops.    ADVANTAGE - The method obtain sulfur phosphorus ammonium product which is nutrient stable, uniform, and has high compressive strength. The sewage treatment device greatly reduces the enterprise environmental protection caused by pressure, cost, and investment risk. The method is small and reduces the risk of investment.    DETAILED DESCRIPTION - Producing sulfur ammonium phosphate product by phosphorus slag sewage treatment technique, involving: (1) mixing with a stirrer, at the same time adding ammonium sulfate slurry, ammonium phosphate slurry and slag, where density of ammonium sulfate solution is 1.24-1.26 g/ml and density of ammonium phosphate slurry is 1.50-1.55 g/ml; (2) after the mixing pump to circulate liquid, heating the slurry to 85-100 degrees C; (3) putting the prepared slurry into the pelleting/drying spray granulation and drying, the drying heat source adopts coal furnace in fluid bed to generate high temperature smoke gas of 550-600 degrees C, obtaining semi-finished product; and 4) drying the semi-finished product, sieving, 2-4 particle enters the cooling tube and cooling to obtain the product, crushing, sieving, pelleting/drying; and (5) using dust scrubber, washing, removing dust. An INDEPENDENT CLAIM is included for a device for producing sulfur ammonium phosphate product, comprising: ammonification reactor (1), reaction circulating pump (2), second-effect evaporator (3), second-effect heater (4), second-effect circulating pump (5), primary mixing part comprises a mixing groove (11) which is provided with stirrer (10), mixing tank is connected to ammoniation reaction of ammonium phosphate slurry pipeline, the mixing groove is further provided with a sulfur ammonium phosphate slurry pipeline and a sewage pipeline, the material liquid circulation part comprises box wall formed by ground paste evaporator, slurry mixer and the liquid circulating pump (8), the drying part comprises a spraying pump, a pelleting drier, a hot-blast stove and a heater, the spraying pump is provided with a material liquid evaporator and the drier, and the heater (18) is connected with the drier, a heater through the hot-blast stove a hot-blast air; then the hot-blast stove is provided with a bucket elevator motor, a hot-blast stove, a bucket elevator is connected with a coal feeding belt, the crushing and sieving part comprises a semi-finished product bucket elevator, a semi-finished product (20), returning the crusher and a belt, the semi-finished product sieve is a bucket elevator a semi-finished product is connected with the drier is a semi-finished product is connected with returning crusher, a semi-finished product to a return outlet of the crusher is provided with a returning belt, a returning belt to the pelleting drier, the cooling wrap portion comprises a product cooling cylinder, the product cooling cylinder is provided with covering agent adding port, the tail gas washing part comprises a cyclone dust collector, the Venturi washer and a tail gas draught fan.