Ignition of Titanium Cladded Steel in Pressure Oxidation Leaching Autoclaves

摘要

The mining industry utilizes pressure acid leaching (PAL) and pressure oxidation leaching (POX) autoclaves constructed out of titanium cladded steel for the refinement of certain ore bodies. Previous work showed that ignition was possible in elevated temperature and pressure environments like those inside POX autoclaves due to the exothermic nature of the oxidation of titanium. This study focused on the characterization of the damage to POX autoclave caused by a promoted fire on the titanium surface. Examination using scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), and light microscopy identified TiO, α-Ti and TiO dendrites, Fe_1Ti intermetallic compound, and TiC in the resolidified portion of the titanium cladded steel flange. The exothermic nature of the formation reactions of these phases is believed to help sustain the titanium fire and melting of the flange. A thermodynamic model was developed to determine the amount of heat generated during the formation of the different phases.