A green approach for simultaneously preparing Ti5Si3 and Ti5Si4-TiAl3 alloys using spent SCR catalyst, Ti-bearing blast furnace slag, and Al alloy scrap

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Vol. 430; p. 132916
• Main Authors: Zhang, Yakun, Lei, Yun, Ma, Wenhui, Shi, Zhe, Chen, Qiushi, Li, Zhanchao, Wang, Chao
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15.02.2022
• Subjects: Extraction; Separation and purification; Ti5Si3; Ti5Si4-TiAl3; Waste treatment; Ti5Si4-TiAl3; Extraction; Waste treatment; Ti5Si3; Separation and purification
• ISSN: 1385-8947; 1873-3212
• DOI: 10.1016/j.cej.2021.132916

[Display omitted] •A green approach is proposed for the extraction of valuable metals from wastes.•The entire process produces no carbon, waste acid, or waste gas.•A new approach for preparing Ti5Si3 alloy and Ti5Si4-TiAl3 alloy.•Three wastes are cleanly utilized through an approach. Spent SCR catalyst (SSC), Ti-bearing blast furnace slag (TBFS), and Al alloy scrap (AAS) are industrial wastes that are rich in Ti and Al. To utilize Ti and Al resources in these three wastes, here, an efficient approach is proposed to prepare two useful alloys, Ti5Si3 and Ti5Si4-TiAl3, using the three wastes as raw materials. First, AAS was used as a reductant to extract Ti and Si from the SSC and TBFS and simultaneously prepare Ti-Si-Al alloys. The effect of the crucible (Al2O3 and MgO crucibles) and CaO addition (slagging agent) on Al reduction was investigated, and the results showed that a MgO crucible and the addition of CaO increased the extraction ratio of Ti and Si. Then, Ti5Si3 and Ti5Si4-TiAl3 alloys were prepared sequentially by the separation of molten Ti-Si-Al melt via electromagnetic directional crystallization. Impurities in the Ti-Si-Al alloy were removed during electromagnetic directional crystallization. No carbon, waste acid, and waste gas were discharged throughout the whole production process. This work provides a green, high-efficiency, and low-cost method that also treats accumulated SSC, TBFS, and AAS wastes.