An Alternative Route For Manufacture Of Diammonium Phosphate

The present study was undertaken with the aim of producing Diammonium Phosphate (DAP) using air as a source of nitrogen and bones a source of phosphoric acid. Oxygen was removed from air by passing air over heated copper granules in the temperature range of 300oC – 500oC. Copper granules were heated using charcoal packed in a ceramic charcoal stove. The nitrogen was reacted with lithium to form lithium nitride which was hydrolysed to produce ammonia. The phosphoric acid extracted by boiling bones with concentrated hydrochloric acid or phosphoric acid was reacted with ammonia produced from hydrolysis of lithium nitride to form diammonium phosphate. The percentage concentration of phosphorus in the fertilizer was determined using U.V spectroscopy whereas that of nitrogen was determined by titration.  The cost of energy for the production of one tone of DAP using this procedure was calculated and results show that the total energy required was 4.95 GJ. This is equivalent to 1375 kW. The cost of basic materials ( operational costs and production costs) of producing one tone of DAP using this procedure was found to be $1070.88 while the estimated cost of regenerating lithium from lithium chloride was 1.26 GJ, which is equivalent to 350 kW.