Method and an installation for producing granulated triple superphosphate (TSP)

A method of producing granulated triple superphosphate, comprising the following steps:

• i preparing a slurry of previously ground phosphate and a solution of phosphoric acid;
• ii granulating the slurry;
• iii drying the granulated product;
• iv separating the granulated product by grain size;
• v disposing of and scrubbing waste gases;
• and
• vi recycling rejected finished product after grain size separation;
• the improvement comprising:
• preparing the slurry of step i via a premixing operation using a premixer for the phosphate and the acid with said premixer being situated upstream from a reactor having a reaction tank in which the acid solution attacks the granulated phosphate, with said premixing operation accomplished by guided insertion of the previously ground and measured-out phosphate into the premixer through a flexible tube having a free end defining a confined area and with said flexible tube being deformable along an axial path and by spraying the phosphoric acid solution into the premixer under pressure through the confined area of said tube for contacting the phosphate at the end of the guided axial insertion path at an oblique angle relative to the direction of said phosphate whereby the free end of said flexible tube is set in motion to randomly move about said premixer by the pressure from said acid for ensuring thorough premixing of the phosphate within said premixer without clogging.