Enhancing The Recyclability of Titanium. A Case Study

Abstract

Titanium, a metal that is abundant in the earth's crust and known for its exceptional properties, faces major barriers when it comes to widespread use. These challenges arise from the high costs associated with extraction, therefore limited opportunities for utilisation. The aim of this project is to develop a new approach to recycling titanium scraps to promote sustainability for titanium. The literature review in this thesis shows the titanium extraction process, metallurgy, and the methods of titanium recycling. Titanium recycling uses conventional and newer, more sustainable methods. Titanium and its alloys are usually remelted using electron-beam melting or vacuum arc remelting. These methods have drawbacks. Energy consumption, water, and air pollution are examples. Newer environmentally friendly and economically viable methods like hydrogenation-dehydrogenation, ball milling (BM), Continuous Extrusion (Conform), and FAST-forge can recycle titanium scrap into powders and near-net shapes. This thesis emphasises the complexity of these processes and the importance of developing a more effective approach to enhance the recyclability of titanium. The BM process has been chosen in the case study due to its ability in generating controlled powders from scrap. However, removing impurities from scraps requires several time- consuming steps before BM. So, the case study has proposed a new recycling technique (hybrid process), that combines molten salt electrolysis and then BM to convert Ti-6Al-4V scraps into a high-purity powder feedstock intended for additive manufacturing purposes. The hybrid process replaces the impurity cleaning steps before BM with molten salt electrolysis, which decreases the number of required steps. The hybrid process achieves a high purity level of 99.94%, allowing the efficient collection of valuable vanadium metal. Moreover, the hybrid process might provide environmental benefits, reduces energy consumption, lowers greenhouse gas emissions, and decreases global warming potential. The hybrid process could be considered as an enhancement in titanium recycling, offering a sustainable solution for tackling titanium scraps.