2015-Sustainable Industrial Processing Summit
SIPS 2015 Volume 11: Recycling & Environmental
| Editors: | Kongoli F, Havlik T, Pagnanelli F |
| Publisher: | Flogen Star OUTREACH |
| Publication Year: | 2015 |
| Pages: | 410 pages |
| ISBN: | 978-1-987820-34-8 |
| ISSN: | 2291-1227 (Metals and Materials Processing in a Clean Environment Series) |
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Reclamation of Valuable Metal Cations from Waste Slags through a Novel Mechanical Approach
Sung Suk Jung1; Il Sohn2;1YONSEI UNIVERSITY, Seoul, Korea (Republic of [South] Korea); 2YONSEI UNIVERSITY MATERIALS SCIENCE AND ENGINEERING, Seoul, Korea (Republic of [South] Korea);
Type of Paper: Regular
Id Paper: 467
Topic: 7
Abstract:
The optimized particle-size-dependent separation methodology of pulverized electric arc furnace (EAF) slag to lower Fe contents has been sought via consideration on the microstructure and physical properties of each solid phases. Vickers hardness and fracture toughness were measured on the spinel and amorphous phases within the solidified slag by the indentation method after isothermal cooling processes which were intended for spinel growth. The differences in the hardness between each phase were enlarged when the slag was isothermally cooled. The variation in the hardness of the spinel was observed in the slags at different FetO/Al2O3 mass ratios and isothermal cooling temperatures, showing reduced hardness of the amorphous phase with isothermal cooling time. Structural studies using X-ray diffraction (XRD) and Raman spectroscopy suggested that the formation of the triclinic unit cell which expands with the increased FetO/Al2O3 ratio results in decrease of hardness for the primary spinel crystals and structural transformation into silicate-dominant with increased isothermal cooling period leads to densification for the amorphous phase and consequent lower hardness. Fracture toughness could be calculated by using the crack information obtained from the Vickers hardness test and Young's modulus could be calculated based on the force-displacement curves from nano-indentation test. The controlled milling process produced particles of different size for each phase due to the distinguished fracture toughness allowing separation of Fe content within the EAF slag powder based on the particle size.