解淀粉芽孢杆菌对粉煤灰浸矿脱硅的研究

Optimization analysis based on bio-leaching of silicon from fly ash by Bacillus amyloliquefaciens

采用解淀粉芽孢杆菌ZGW-12对粉煤灰进行生物脱硅研究,确定菌种培养和矿物脱硅的最适条件。实验确定细菌培养的初始接菌量为5 mL,保持30℃恒温并在125 r/min条件下培养4 d达到生长稳定期。粉煤灰脱硅最佳条件为:7.5%浓度的无菌矿浆100 mL中接菌5 mL,在30℃和150 r/min的条件下摇瓶浸出。粒度小于75μm的粉煤灰浸矿7 d后矿浆中Si 2+浓度高于158 mg/L,脱硅效果较好。将粉煤灰浸矿31 d,测定矿浆中Si 2+、Al 3+浓度分别可达306 mg/L和0.5 mg/L,说明细菌对粉煤灰中硅元素浸出效果较好。结合SEM-EDS和FTIR检测发现ZGW-12易吸附于矿样表面,使其中Si—O键断裂,对粉煤灰有较好的脱硅提铝效果。

In this study,the bio-desilication experiment of fly ash using Bacillus amyloliquefaciens ZGW-12 is determined the optimal conditions for strain culture and bio-desilication of ore samples.The initial inoculation amount of bacteria culture is determined to be 5 mL,maintained at 125 r/min and the temperature of 30℃for 4 days to reach a growth stable period.The best conditions for bio-desilication of fly ash are determined that 5 mL bacteria culture medium is inoculated in 100 mL sterilized medium with 7.5 g fly ash and it is bio-leaching at 30℃and 150 r/min.The Si 2+concentration in the ore pulp with a particle size of less than 75μm is all higher than 158 mg/L after 7 days bio-leaching,meaning the its bio-desilication is better.Bio-leaching the fly ash for 31 days measured that Si 2+concentration could reach 306 mg/L,while Al 3+concentration is basically maintained at 0.5 mg/L,illustrating that ZGW-12 have a good effect on the bio-desilication of fly ash.Combined with SEM-EDS and FTIR analysis,ZGW-12 is easily adsorbed on the surface of the fly ash,and the Si—O bond is broken in the ore sample,which had a good effect on extracting silicon and retaining aluminum with fly ash.