期刊
SCIENCE OF THE TOTAL ENVIRONMENT
卷 770, 期 -, 页码 -出版社
ELSEVIER
DOI: 10.1016/j.scitotenv.2021.145241
关键词
Solid-waste coal gangue; Bacillus pasteurii; Bio-mineralized underground backfilling material; Circulation perfusion method; Strain domestication
资金
- National Science Fund for Distinguished Young Scholars [51725403]
- National Natural Science Foundation of China [52004271, 51874287]
This study proposes a cement-free eco-friendly technology using Bacillus pasteurii for CG-based backfilling material, which can consolidate loose grains with high biomineral content and no pollution. Through strain domestication and comprehensive analysis, the method successfully produces bio-mineralized material with significant influence on biomineral deposition.
Solid-waste coal gangue (CG) mixed with cement as underground backfilling material is widely applied in coal mines throughout China. However, thismaterial can pollute the environment during its production, preparation, and transportation, which ismainly caused by cement. As a cement-free eco-friendly technology, microbially induced carbonate precipitation (MICP) technology can produce biomineralization products to consolidate loose grains, and the microbial growth environment is adapted to underground temperature with no pollution. To this end, this study gets the Bacillus pasteurii with special resistance by strain domestication, proposes a CG-based bio-mineralized underground backfilling material without using cement, and analyses the characteristics of it from macro- to microscopic perspectives by dissolution test, scanning electron microscopy (SEM), Energy-dispersive spectroscopy (EDS) and X-ray diffraction (XRD). The results indicate that strain domestication leads to B. pasteurii, which can withstand CG leaching solution and 1 M urea simultaneously. This satisfies the basic requirements of CG based mineralized material. Through the circulation perfusion method, the intact CG based biomineralized specimens are obtained. Macroscopically, the bacteria bind gangue grains into a whole with high biomineral content (11.66%). The utilization rate of mineralizing solution is up to 66.82% which makes good use of raw materials. Microscopically, a new crystal formation is observed, and CG particles are consolidated well where the crystals precipitate to fill the pores and bind the particles together. Hence this method has a significant influence on the deposition of biominerals. Meanwhile the biomineralization improves the microstructure considerably and bonds the CG particles as a whole. A comprehensive analysis of the test results shows that, from an environment viewpoint, the preliminary study of new CG based bio-mineralized material is successful. (C) 2021 Published by Elsevier B.V.
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