Abstract
The oxidation of ferrous hydroxide Fe (OH) 2 was investigated by using an experimental apparatus. When the precipitates of Fe (OH) 2 in the brine was oxidized by the air injected, iron compounds produced at various temperatures of oxidation had different forms, e. g., Fe3O4 at high temperature and γ-FeOOH at low temperature. And the boundary of formation of γ-FeOOH was extended to higher temperature stage, as the ratio of iron concentration in the brine to air flow rate through the brine decreased.
The data on the chemical compositions of the iron sludge formed in the two plants, each of which had a capacity of 100m3/d and 2,000m3/d respectively, were obtained. In these plants, the iron compound was oxidized by the dissolved oxygen in the brine. The concentration of the iron compound and the dissolved oxygen in the plants were very low in comparison with the experimental data, so the oxidation condition of the iron compounds in the plants differed from the condition of the fundamental experiment. However, the forms of the iron compounds produced in the plants were similar to the ones experimentally produced. In the 100m3/d plant, in which the ratio of iron to oxygen was large, the formation of Fe3O4 was observed in the wide range. On the other hand, in the 2,000m3/d plant, in which the iron concentration in the brine was low, the most of the iron sludge had the form of γ-FeOOH.
