Hydrometallurgy Research Center, St. Petersburg, Russia

A. Yu. Lapin, Chief Researcher, Candidate of Technical Sciences, e-mail: lapin-a@gidrometall.ru
M. V. Klementyev, Deputy General Director, e-mail: klementev-m@gidrometall.ru

Ya. M. Shneerson, Director of Science and Development, Doctor of Technical Sciences, Professor, e-mail: shneerson-y@gidrometall.ru

Empress Catherine II St. Petersburg Mining University, St. Petersburg, Russia
V. I. Bolobov, Professor, Chair for Mechanical Engineering, e-mail: Boloboff@mail.ru

Modern autoclave-hydrometallurgical processes, on the one hand, involve high parameters (temperature, pressure, aggressive environment), and on the other, require the use of high-strength metallic materials, particularly titanium and titanium-based alloys. However, the presence of oxygen in the autoclave unit poses a real risk of spontaneous titanium combustion, which can lead, and has repeatedly led, to accidents and tragic consequences. Preventing such an emergency is possible through strict adherence to existing rules and regulatory requirements, which, unfortunately, are not always met. Spontaneous titanium combustion occurs when three conditions are simultaneously present: the presence of oxygen flow, the formation of a juvenile titanium surface, and the destruction (integrity damage) of the titanium sample. The main requirements for the safe use of titanium materials in autoclave oxidation are: the selection of metal for all non-titanium parts inside the autoclave from known-resistant materials that prevent their destruction and impact contact with titanium; prohibit the supply of oxygen to a cold autoclave or one that is not filled with working fluid; prevent the supply of high-pressure oxygen to the vessel or the removal of oxygen from the autoclave through titanium piping. Compliance with established rules enables the efficient and safe operation of modern industrial autoclaves, including units with titanium housings. The same rules must also be strictly followed when working with small-volume laboratory units.

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