“…al. [8], [7], [21], dealing with the following acid-base system H + , H 3 PO 4 , H 2 PO − 4 , HPO 2− 4 , PO 3− 4 , OH − , which are assumed to be at equilibrium, which is reached instantaneously. There are also a formation of salts (CaHPO 4 and Ca 3 (PO 4 ) 2 ), which may stay in solution as well as precipitate and form a solid phase.…”