Granulating thomas phosphate potash fertilizers - with increased yield of useful size particles

摘要

Process for increasing the yield and throughout in the granulation of PK fertilizers prepd. from Thomas phosphate (I) and K salt soln. comprising (I) with practically dry K salt contng. 50-60% K2O; (2) moistening prod. to 2-5 wt.% water; (3) moistening recycled material from stage 9 to 2-5 wt.% water; (4) discharging damp material to a worm granulator and adding more water to give 9-13 wt.% moisture; then (5) to a granulating drum of 10 degrees-24 degrees slope rotating at 8-15 rpm; (b) drying the damp granules at an exit temp. of 110-140 degrees C; (7) sieving the hot granules, removing over-sized particles, grinding and returning to sieve; (8) collecting the granules and cooling to 30-60 degrees C and (9) recycling residu to stage 3. Process gives high proportion of useful 1-4mm size particles and less material to be recycled.