Lagno F, Demopoulos G P
Department of Mining, Metals and Materials Engineering, McGill University, 3610 University St., Montreal, QC, Canada H3A 282.
Environ Technol. 2006 Nov;27(11):1217-24. doi: 10.1080/09593332708618735.
The dissolution mechanism and stability of a synthetic hydrated aluminium phosphate, AlPO4 x 1.5H20 (AlPO4-H3) was investigated at 22 degrees C over the pH range 2.4 to 8.8. AlPO4 x 1.5H2O was found to be more soluble than the better known dihydrate (variscite, AIPO4 x 2H2O) hence proving to be metastable. This material was determined to undergo incongruent dissolution at pH around 3.0 and higher producing initially amorphous Al(OH)3 which gradually (within 30-day dissolution period) converted to the stable gibbsite phase. Upon evaluation of the experimental data with PHREEQC it was possible to calculate the solubility product ( logKsp ) and the standard Gibbs free energy of formation (deltaGf,0) for AlPO4 x 1.5H2O to be respectively-- 20.46+/-0.40 and -1980.5+/-.0 kJ mol(-1) at 22 degrees C.
在22摄氏度、pH值为2.4至8.8的范围内，对合成水合磷酸铝AlPO₄·1.5H₂O（AlPO₄-H₃）的溶解机制和稳定性进行了研究。发现AlPO₄·1.5H₂O比更知名的二水合物（磷铝石，AlPO₄·2H₂O）更易溶解，因此证明其为亚稳态。该物质在pH约为3.0及更高时会发生不一致溶解，最初生成无定形Al(OH)₃，其在30天的溶解期内逐渐转化为稳定的三水铝石相。在用PHREEQC评估实验数据后，可以计算出AlPO₄·1.5H₂O在22摄氏度时的溶度积（logKsp）和标准生成吉布斯自由能（ΔGf⁰）分别为 -20.46±0.40和 -1980.5±0.0 kJ·mol⁻¹。
