Synthesis of high-purity titanium powder from biomedical waste titanium chips using a mechanical grinding method

In this study, Cp-Ti particles were produced by using mechanical grinding method by supporting the wet pre-grinding of titanium chips obtained from turning, which is one of the machining methods, by using different ball-powder ratios and grinding times. It was observed that the smallest particle size obtained with 15:1 ball-powder weight ratio was approximately 15 times smaller compared to the powders produced with 5:1 ratio. After 4 hours of grinding process with 15:1 ball-powder ratio, TiO2 (Anatase and Rutile) phases were observed in the structure of Cp-Ti particles, while no oxidation signs were found in the XRD analysis results of the grinding processes performed using lower ball-powder ratios (5:1 and 10:1). At 0.5 hours of grinding time, the lowest apparent density and hardness were determined as 2.8 g/cm³ and 126 HV, respectively. In the 7-hour milling period, the highest apparent density and hardness were measured as 3.45 g/cm³ and 325 HV, respectively. In addition, the response of TiO₂ powders obtained from recycled Ti powders to hydrogen gas was tested, and a linear increase in response was observed from 1000 ppm to 40,000 ppm. For characterization processes, scanning electron microscope (SEM), X-ray diffractometer (XRD), energy dispersive spectrometer (EDS), thermogravimeter analysis (TGA) and a master sizer device operating with the laser light scattering principle for powder size measurement were used.