| 摘要 |
H3PO4 with a P2O5-content of 40-55% and an F-content of max. 0.3% is neutralised to the first H-ion with natural phosphate of 10-40% at 90-130 degrees C. The slurry produced is reacted with CaCO3, CaO or Ca(OH)2 or mixts. at 50-100 degrees C until the pH of its 0.01M aq. soln. is 3-6. The resulting solid is then dried at 80-150 degrees C sieved, milled and packed. The mono- and dicalcium phosphates produced are used as animal feedstuffs. The process may also be carried out to produce dehydrated Ca phosphates. (a) Compared with processes reacting H3PO4 with CaO, CaCO3 or Ca(OH)2 expensive H3PO4 is reduced by 4-15% and calcium reagents by 10-40%. CaSO4 is removed in bulk in the solid first phase preventing settling on walls and stirrers. Development of gas is reduced by 10-40% and foaming is reduced. |
