| 摘要 |
<p>Prepn. of acicular goethite (alpha FeO.OH) which can readily be made into magnetic gamma Fe2O3, which comprises precipitating ferrous hydroxide at 60 degrees C using an excess of alkali such that no local excess of Fe++ ions occurs, oxidising this hydroxide at 20-60 degrees C, and then bringing the suspn. to the boil to complete crystallisation. The final concn. of alpha FeO.OH, which should have a particle size 0.5 mu, must be 15 gpl. The appts. used for the pptn. and oxidn. is a casting dish of FR 1157156.</p> |
