Eco-Friendly Pretreatment of Titanium Turning Scraps and Subsequent Preparation of Ferro-Titanium Ingots

In this study, an eco-friendly pretreatment process was developed to recycle titanium turning scraps and ferro-titanium ingots with low gaseous impurities were prepared using recycled titanium turning scraps. The amount of gaseous impurities of titanium scraps before removing the machining oils on the surface was as high as 20000 ppm. To remove these oils, the eco-friendly pretreatment solution excluding acid solution or organic solvent was developed. As a result, the respective gaseous impurities of oxygen, nitrogen and carbon showed reduction ratio of 54.0%, 96.2%, and 98.4% as compared to the raw material under the optimum condition of NaOH + Na4P2O7. When a Fe-Ti ingot was prepared with the eco-friendly pretreatment scraps under the optimum conditions, the total content of gaseous impurities in the Fe-Ti ingot with pretreated Ti scraps was reduced by 81% (O, N, C = 1365 ppm) compared to the Fe-Ti ingot with raw Ti scraps. (Received March 18, 2019; Accepted July 23, 2019)