MATERIAL FOR PHOSPHATE FERTILIZER AND METHOD FOR PRODUCTION THEREOF

摘要

A material for a phosphate fertilizer, which comprises a slag being formed in the dephosphorization of hot−iron and containing phosphoric acid and has a composition wherein the content of phosphoric acid satisfies the following formula (1), preferably formula (2): [P2O5] ≥ 5.6 X [F] + 7 ..... (1) [P2O5] ≥ 5.6 X [F] + 10 ..... (2) wherein [P2O5] and [F] represent the contents of phosphoric acid and fluorine in the slag (mass %), respectively; and a method for producing the material which comprises providing a hot−iron having a satisfactorily reduced Si concentration, adding an oxygen source and a CaO source to effect the dephosphorization of the hot−iron, or comprises supplying a CaO source and gaseous oxygen to a hot−iron in a specific form and under a specific condition to effect the dephosphorization of the hot−iron. The material for a phosphate fertilizer has excellent fertilizer characteristics.