ABSTRACT
Processes for phosphate fertilizer production from phosphate rock are divided into a wet process using acid or alkali, and a dry or a thermal process using heat. Thermal phosphates may be divided into fused phosphate and calcined phosphate by the production process. The melt was water quenched and minus 10 mesh portion of the products were subjected for citric solubility tests after ground to pass 100 mesh screen. Moreover, for the calcined phosphate added with phosphoric acid and sodium, the amount of silica was as critical as with the phosphate without phosphoric acid. The commercial production of the calcined defluorinated phosphate using small amounts of phosphoric acid and sodium salt was started in Japan in late 1950s and then in the United States and Israel.
