| 摘要 |
Bicalcium phosphate for use in animal feeds is prepd. by reaction of concd. phosphoric acid on calcium oxide until a dry powder prod. is obtd. The concn. of phosphoric acid is pref. 50-75% H3PO4 and the lime contains 80-100% CaO. The lime has a particle size such that 90% passes a 5000 openings/cm2 sieve and 100% passes 1000 openings/cm2 sieve. The phosphoric acid may be sprayed onto the lime, the reaction pref. being effected with the starting materials being added portionwise. The heat of reaction is sufficient to evaporate the excess water introduced with the acid. The product is dry, homogeneous and free from lumps. In an example, 550kg. lime (94% CaO) passing through a sieve of 5000 openings/cm2 was treated with 1580kg. 55.8% phosphoric acid at a rate of 900 litres/hr. On complete addition, 150kg. lime and 400kg. acid were added at the same rate, and after 5 minutes, a further 200kg. lime, then 520kg. phosphoric acid. At the end of the addition the mixt. was allowed to react for 90 minutes to give 2500kg. bicalcium phosphate contg. 2.5% water. |
