| 摘要 |
<p>PURPOSE:To obtain surely and with good yield a ferromagnetic divalent-trivalent iron salt holding stably characteristics as an active substance. CONSTITUTION:An alumina sol wherein a boehmite alumina (gamma-Al2P3.H2O) of neutral zone is a main component is formed by incorporating basic aluminum sulfate (Al:SO4=1.8:1.0, the concn. is 5%) and soldium hydroxide (1N, NaOH) into an iron (II) sulfate soln. (1N, FeSO4) as a divalent iron salt soln. Then, it is stirred rapidly while air is made to blow therein and a sol mixed with alumina wherein a ferromagnetic divalent-trivalent iron salt is homogeneously dispersed and carried under the condition of an ultrafine particle is formed. Then, after this mixed sol is washed by means of electrophoresis, it is kept on standing in a nitrogen-sealed container for 24 hours, and then, it is dehydrated and dried by means of vacuum concn. to obtain a powdery alumina-iron salt composite contg. the divalent-trivalent iron salt.</p> |
