Abstract:
Reaction of Eppawela apatite with HC1 has been investigated in an attempt to convert rock phosphate to phosphorus enriched manure using a simple & low cost method. Although direct reaction of apatite with HC1 lead to a highly hygroscopic product, physical condition of this material could be improved by the treatment with ammonia. Apatite reaction with 12% HC1 followed by PH adjustment using an alkali, leads to the precipitation of dicalcium phosphate (CaHPO4), which could readily be used as a P-fertilizer. Use of ammonia & ammonium salts has an added extra advantage in that the product contains nitrogen in addition to phosphorus. And also the addition of KCl to the mixture ensured availability of K in required proportions. Since the cost of this product depends mainly on the cost of HC1, partial combination with Hydrochloric acid recognized as a potentially useful and economical method.
