Effect of Ultrasonic Cleaning of Titanium Turning Scraps Immersed in Alkaline Solution and Subsequent Preparation of Ferrotitanium Ingots

Yoo, Suhwan; Chae, Jikwang; Oh, Jung-Min; Lim, Jae-Won

doi:.59.2.113

Korean Journal of Metals and Materials > Volume 59(2); > Article

Research Paper

doi: https://doi.org/10.3365/KJMM.2021.59.2.113

Effect of Ultrasonic Cleaning of Titanium Turning Scraps Immersed in Alkaline Solution and Subsequent Preparation of Ferrotitanium Ingots

Suhwan Yoo¹, Jikwang Chae¹, Jung-Min Oh¹, Jae-Won Lim^1,2

¹Division of Advanced Materials Engineering, College of Engineering, Jeonbuk National University, Jeonju 54896, Republic of Korea
²The Research Institute of Mineral Resources and Energy Development, Jeonbuk National University, Jeonju 54896, Republic of Korea

Correspondence

Jae-Won Lim ,Tel: +82-63-270-2307, Email: jwlim@jbnu.ac.kr

Received: 13 August 2020; Accepted: 29 December 2020. Published online: 27 January 2021.
*Suhwan Yoo and Jikwang Chae contributed equally to this work.

ABSTRACT

Ti has excellent properties but is more expensive than other materials due to its high melting point, high reactivity and difficult processability. One way to lower the production cost of Ti products is to recycle Ti scraps. Before recycling Ti scraps, pretreatment to remove contamination is essential. Ti scraps can be pretreated in an alkaline solution, thus eliminating the use of acidic solutions. However, a pretreatment only involving immersion in alkaline solution requires a high concentration solution, and has low efficiency. Therefore, in this study, an optimized ultrasonic cleaning process is introduced to pretreat Ti scraps in a lowconcentration alkaline solution. The carbon content of Ti scraps before pretreatment was 6,800 ppm, and showed a sharp decrease with pretreatment. Using this pretreatment process, C, O, and N impurities were removed by 97.6%, 58.8%, and 29.2%, respectively. Ferrotitanium ingots were then produced by vacuum arc melting (VAM) and plasma arc melting (PAM) using the pretreated Ti scraps and electrolytic iron. Differences in ingots melted by VAM and PAM were investigated. As the time was increased, the content of impurities decreased. Subsequently, a ferrotitanium ingot prepared using the pretreated Ti scraps showed that the carbon concentration in the ingot was less than 200 ppm.

Keywords: Ti scraps, pretreatment, recycling, ultrasonic cleaning, ferrotitanium