Enhancement of P2O5 Content in SSP Made from Local Rock Phosphate of Pakistan

The Phosphorus content is a necessary part of fertilizers used in Pakistan and is readily available in single super phosphate fertilizer. Pakistani rock phosphate being of low grade cannot be used by conventional method to prepare good quality SSP. This rock however, can be used by some unconventional techniques for preparing some better quality fertilizer. For the subject study rock phosphate samples were collected from Hazara, Pakistan and were ground to 150 mesh level containing 24% total phosphate pentoxide (P2O5) content and were treated with different ratios of sulphuric acid (H2SO4) and phosphoric acid (H3PO4). Seven samples with composition comprising of fix weight of rock phosphate i.e. 100 gm were prepared by treating it with H2SO4 (diluted to 65%) and H3PO4 (of 85% purity) in w/w ratios of (13:1, 13:2, 4:1, 11:4, 2:1 and 3:2) were manually prepared and analyzed through spectro-photometric method before and after a curing period of two weeks. The results obtained showed that there was enhancement in P2O5 up to 22.9% total and 19.9% available P2O5 content by addition of H3PO4 and H2SO4 (in weight ratios of 3:2) to the conventional formulation of single super phosphate (SSP) containing the rock phosphate and H2SO4 only. The results lead to conclude that the phosphorus content in SSP made from low quality local rock phosphate can be effectively enhanced and a market grade SSP(with 18% available P2O5) can be prepared using the local rock without any need to import rock phosphate from other countries.