The reactions of gamma-irradiation on 5 mm beta-FeOOH in the presence of is
opropanol and water have been investigated. In the initial stage of the gam
ma-irradiation, beta-FeOOH turned into alpha-FeOOH. With the gamma-irradiat
ion continued, alpha-FeOOH was slowly reduced to Fe3O4. After the gamma-irr
adiation with a dose of 64.3 kGy, all the beta-FeOOH and alpha-FeOOH disapp
eared and the product was a single phase of Fe3O4, which had an average par
ticle size of 54 nm. The process of this reaction is discussed. The gamma-i
rradiation of beta-FeOOH should be a new method of preparing magnetite. (C)
1999 Published by Elsevier Science Ltd. All rights reserved.