Chen, H.-J.; Lin, Y.-R.; Tang, C.-W.; Hung, Y.-C. Application of Biomineralization Technology in the Stabilization of Electric Arc Furnace Reducing Slag. Appl. Sci.2023, 13, 10435.
Chen, H.-J.; Lin, Y.-R.; Tang, C.-W.; Hung, Y.-C. Application of Biomineralization Technology in the Stabilization of Electric Arc Furnace Reducing Slag. Appl. Sci. 2023, 13, 10435.
Chen, H.-J.; Lin, Y.-R.; Tang, C.-W.; Hung, Y.-C. Application of Biomineralization Technology in the Stabilization of Electric Arc Furnace Reducing Slag. Appl. Sci.2023, 13, 10435.
Chen, H.-J.; Lin, Y.-R.; Tang, C.-W.; Hung, Y.-C. Application of Biomineralization Technology in the Stabilization of Electric Arc Furnace Reducing Slag. Appl. Sci. 2023, 13, 10435.
Abstract
Most of the current methods for stabilizing electric arc furnace (EAF) slag are time-consuming and cannot be completely stabilized. In view of this, this study aimed to apply microbial‑induced calcium carbonate precipitation (MICP) technology in the stabilization of EAF reducing slag, and this was to be achieved by using the reaction between carbonate ions and free calcium oxide (f-CaO) in reducing slag to form a more stable calcium carbonate to achieve the purpose of stabilization. The test results showed that, when the EAF reducing slag aggregates (ERSAs) were immersed in Bacillus pasteurii bacteria solution or water, the f-CaO contained in it would react such that stabilization was achieved. The titration test results showed that the f-CaO content of the ERSAs immersed in the bacterial solution and water decreased. The expansion test results of the ERSAs that were subjected to hydration showed that the seven-day expansion of ERSAs after biomineralization could meet the Taiwan regulation requirement of a less than 0.5% expansion rate. The thermogravimetric analysis showed that both the experimental group and the control group might contain calcium carbonate compounds. The results of the X-ray diffraction analysis showed that the CaCO3 content in the ERSAs that were immersed in the bacterial solution was significantly higher than those that were immersed in water. Moreover, the compressive strength test results of concrete prepared with ERSAs showed that the compressive strength of the control group concrete began to decline after 28 days. In contrast, the experimental group concrete had a good stabilization effect, and there was no decline in compressive strength until the age of 180 days. At the age of 240 days, the surface cracks of the experimental group were particularly small, while the surface of the control group showed obvious cracks. These results confirmed that a mineralization reaction with B. pasteurii bacteria could be used as a stabilization technology for ERSAs.
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