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| Experiment and Mechanism of Microbial Dealkalization in Red Mud |
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Received:April 23, 2023
Revised:April 28, 2023
Accepted:May 05, 2023
Published Online:August 11, 2023
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| DOI：doi：10.3969/j.issn.1007-7545.2023.09.008 |
| KeyWord:red mud; dealkalization; Bacillus megaterium; microorganism; organic acid |
| Author | Institution |
| YAN Xudong |
河南理工大学 |
| ZHU Xiaobo |
河南理工大学 |
| LI Wang |
河南理工大学 化学化工学院 |
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| Abstract: |
| Red mud is an alkaline industrial waste produced in aluminum industry, and its strong alkalinity prove to be the primary factor restricting the comprehensive utilization of red mud. Microbial dealkalization of red mud was studied to reduce the harm to the environment. The effects of Bacillus megatherium powder addition amount, treatment time, liquid-solid ratio, culture method and air supply on the dealkalization of red mud were investigated. The mineral-phase composition and surface morphology of red mud and its dealkalization slag were characterized by XRD and SEM test, and acid production of strain was analyzed by HPLC. The results show that pH value of red mud samples drops from 10.3 to 6.5, and keeping a constant figure at 7.5 under the conditions including shock culture, amount of red mud of 20 g, amount of bacteria powder of 20 g, the ratio of liquid to solid of 7.5. The XRD analysis implies that the diffraction peak of calcium nepheline tremendously weakened, while that of calcium carbonate is strengthened. The SEM results exhibit a more regular physical morphology of dealkalization slag treated by microorganism. The decrease of pH of red mud results from the neutralization of acid produced by microbial metabolism. The HPLC data demonstrates that the organic acids metabolized by Bacillus megaterium are mainly propionic acid and malic acid. |
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