University of Oulu

Lin, Y., Luo, Q., Yan, B. et al. Effect of B₂O₃ addition on mineralogical phases and leaching behavior of synthetic CaO–SiO₂–MgO–Al₂O₃–CrOₓ slag. J Mater Cycles Waste Manag 22, 1208–1217 (2020).

Effect of B₂O₃ addition on mineralogical phases and leaching behavior of synthetic CaO–SiO₂–MgO–Al₂O₃–CrOₓ slag

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Author: Lin, Yong1; Luo, Qingyun1; Yan, Baijun1;
Organizations: 1School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing, 100083, China
2Research Unit of Process Metallurgy, University of Oulu, 90014, Oulu, Finland
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 2.2 MB)
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Language: English
Published: Springer Nature, 2020
Publish Date: 2020-09-10


Boron oxide is frequently applied in modification of stainless steelmaking slag to mitigate the disintegration of slag. In this work, the effect of B₂O₃ on mineralogical phases and hexavalent chromium leaching behavior of synthetic CaO–SiO₂–MgO–Al₂O₃–CrOx slag was investigated. Di-calcium silicate, merwinite, spinel, akermanite, and matrix phase were observed as main minerals in slags by scanning electron microscope (SEM) equipped with energy-dispersive spectrometry (EDS) and X-ray diffraction (XRD) techniques. It was found that 2% B₂O₃ addition is sufficient to eliminate the disintegration of synthetic slag by suppressing the phase transition to γ-Ca₂SiO₄. The size of spinel phase increases with increasing B₂O₃, which could be well interpreted by enhanced Ostwald ripening. The amount of Ca₂SiO4 phase in slag was reduced by addition of B₂O₃; however, excess B₂O₃ (> 2%) addition would significantly increase chromium concentration and overall chromium distribution in Ca₂SiO₄ phase. Leaching results according to US-EPA-3060A method indicated that excess boron oxide addition (> 2%) leads to a significant increase of hexavalent chromium leaching concentrations and should be avoided for stabilizing stainless steel slag.

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Series: Journal of material cycles and waste management
ISSN: 1438-4957
ISSN-E: 1611-8227
ISSN-L: 1438-4957
Volume: 22
Issue: 4
Pages: 1208 - 1217
DOI: 10.1007/s10163-020-01015-4
Type of Publication: A1 Journal article – refereed
Field of Science: 215 Chemical engineering
216 Materials engineering
Funding: Open access funding provided by University of Oulu including Oulu University Hospital. This work was supported by the Academy of Finland for Genome of Steel Grant (No. 311934) and Natural Science Foundation of China (NSFC Contract No. 51774026).
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