| Precipitates of goethite have been obtained by the oxidation of ferrous ion by oxygen as an oxidant in the ferrous sulfate solution which added the various concentration of sodium hydroxide. When the mole ratio, R(=2｜OH ｜/｜Fe^(2+)｜) is 0.5 in the formation of goethite, the reaction seems to begin with the dissociation of ferrous hydroxide and to proceed with the formation of Fe(OH)₂. The reaction mechanism of goethite in R=4 was very different from that in R=0.5. From this fact, the reaction can be thought of oxidation reaction in HFeO₂. As the temperature was increased, the particle length of the products was increased in spite of decreasing of reaction time. When the flow rate of oxygen as an oxidant was increased, both the particle length of product and reaction time were decreased. During the reaction of goethite formation by aging the ferric hydroxide in the condition of 50℃ and pH=2, the hydrolysis reaction of Fe(OH)₃ proceeds with aging time. |
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