分别采用粒度分布测试仪、X射线衍射仪及扫描电镜测定和观察添加1.2×10^-2mol／L对甲基苯甲酸后氢氧化铝晶体的粒度分布、晶型及晶体初期形貌；用Materials Studio Dmol^3模块中的GGA-PW91基组计算对甲基苯甲酸与氢氧化铝（001）面结合前后的态密度、总能量、键合能及费米能级。结果表明，添加1．2×10^-2mol／L对甲基苯甲酸后，与空白相比，产品氢氧化铝的粒径基本不变，晶型不变，初期形貌发生了较大的变化；对甲基苯甲酸不易吸附于氢氧化铝（001）面，不是通过吸附在（001）面来抑制分解的。
α-alanine was adopted as a new additive to elucidate the seeded precipitation mechanism of sodium aluminate solution. α-alanine has the inhibitory effect at the initial period of reaction, but the favorable effect in subsequent reaction. The combined effect of amino and carboxyl group in α-alanine was confirmed by investigating the effect of propionic acid, ethamine and the mixture of propionic acid and ethamine (mole ratio 1-1) on the precipitation of sodium aluminate solution, respectively. The inhibitory effect derives from the adsorption of amino or carboxyl group in α-alanine on the active surface sites of gibbsite, which was confirmed by the alleviating inhibitory effects of propionic acid, ethamine and α-alanine due to the double crystal seed mass. The semi-quantitative IR spectrum analysis of the relative concentrations of Al2O(OH)62- with the band at about 550 cm-1 and polynuclear aluminate ion with the bands at about 880 cm-1 and 635 cm-1, indicates that the dynamic balance among some aluminate species present in sodium aluminate solution is broken due to the addition of α-alanine, thus resulting in the change of the seeded precipitation ratio of sodium aluminate solution.
