Analysis of Adsorption Mechanism of Cobalt on the Crud by Emission Mossbauer Spectroscopy

在本研究所购买的振荡式高压反应釜中，在102ﾟC下研究了镁离子、钙离子、锶离子和锌离子对γ-Fe_2O_3和Fe_3O_4表面钴离子吸附的影响。用发射穆斯堡尔谱研究了钴在凝固物表面的吸附状态，得出以下结论：(1)当块状样品中具有较高八面体择优位置的镁离子先于钴离子被吸附在凝固物表面的八面体位置时，镁离子被吸附在凝固物表面的八面体位置上，从而延缓了具有较高八面体择优位置的钴离子与CRUD的反应。(2)当体相中具有较高四面体晶位择优的锶离子或钙离子优先于钴离子吸附时，钴离子只吸附在晶须表面的八面体晶位上。(3)当块体中具有最高四面体择优的锌离子优先于钴离子吸附在CRUD上时，预计锌离子将被吸附在CRUD上的四面体位置上，并形成最高水平的钴铁氧体。而经锌离子和锌离子处理后的实验结果与未加锌离子的实验结果相同。这一现象可以用锌离子在溶液中的分配比很小来解释。

Effect of pretreatment with Mg^<2+>, Ca^<2+>, Sr^<2+>, or Zn^<2+> ions on adsorption of cobalt ions on gamma-Fe_2O_3 and Fe_3O_4 crud was studied at 102ﾟC in a vibrating-type autoclave which was purchased by this scientific research. Absorption state of cobalt on curd was also investigated by emission Mossbauer spectroscopy and the following conclusions were derived : (1) When Mg^<2+> ions having high octahedral site preference in bulk sample were adsorbed on crud prior to cobalt ions adsorption, Mg^<2+> ions were adsorbed on octahedral site on crud surface, and reaction of crud with cobalt ions having high octagedral site preference was retarded. (2) When Sr^<2+> or Ca^<2+> ions having high tetrahedral site preference in bulk were adsorbed on crud prior to cobalt ions adsorption, cobalt ions were adsorbed only on octahedral sites on crud. (3) When Zn^<2+> ions having the highest tetrahedral site preference in bulk are adsorbed on crud prior to cobalt ions adsorption, it is expected that Zn^<2+> ions are adsorbed on tetrahedral sites on crud and cobalt ferrite is formed at the highest level. However, the experimental result pretreated with Zn^<2+> ions was the same as that without pretreatment. This fact can be explained by small distribuion ratio of Zn^<2+> ions between crud and solution.