Table 1.

The saturation indices (SI) of the different compounds in the PEM medium by pH 8.5, 25 °C treatment were predicted with Visual MINTEQ software

Compounds	lgIAP	lgKsp	SIa
Ca10(PO4)6(OH)2	− 20.90	− 44.33	23.43b
Ca4H(PO4)3·3H2O	− 34.33	− 47.95	13.63b
β-Ca3(PO4)2	− 18.41	− 28.92	10.51b
am2-Ca3(PO4)2	− 18.41	− 28.25	9.84b
Mg3(PO4)2	− 14.08	− 23.28	9.20b
am1-Ca3(PO4)2	− 18.41	− 25.50	7.09b
MgHPO4·3H2O	− 14.47	− 18.18	3.70b
CaHPO4	− 15.92	− 19.28	3.36b
CaHPO4·2H2O	− 15.92	− 19.00	3.08b
Mg(OH)2	14.87	18.79	− 3.93c
MgO	14.87	21.58	− 6.72c
Ca(OH)2	13.42	22.70	− 9.28c
CaO	13.42	32.70	− 19.28c

^aSI saturation index = lgIAP − lgKsp; ^bSI > 1, oversaturation; ^cSI < 1, undersaturation; IAP ion activity product, K_SP solubility product constant