RESUMO
In this study, batch experiments were performed to investigate the effect of temperature on the Fe (II) oxidation and the formation of biogenic secondary iron minerals by Acidithiobacillus ferrooxidan. Results showed that the low temperature significantly inhibited the oxidation activity of A. ferrooxidan. In the FeSO4-H2O biological oxidation system facilitated by A. ferrooxidan, it was found that after 5 days culture, the oxidation rates of Fe (II) in treatments of 10 degrees C and 28 degrees C were 11.81% and 100%, respectively. In addition, it rapidly rose to 95.10% when the temperature was adjusted from 10 degrees C (cultured for 7 days) to 28 degrees C in 1 day, and the maximum oxidation rates were as follows: 10 degrees C (cultured for 7 days) +28 degrees C (2.25 h(-1)) > 28 degrees C (1.42 h(-1)) >10 degrees C (0.81 h(-1)). Furthermore, the XRD patterns showed that the lower Fe (III) supply rate was more conducive to the formation of amorphous schwertmannite in 9K medium at 10 degrees C. Correspondingly, the generation of amorphous schwertmannite was preceded to ihleite at 28 degrees C, and the crystallinity degree of ihleite was getting better with the extension of culture time. Combined with the SEM characteristics, it was judged that the 28 degrees C sample contained jarosite and schwertmannite.
