In the POX process, the ore is crushed and mixed with water to create aqueous slurry that is then heated and fed into an autoclave.
Oxygen is added to the vessel to react with the slurry. The POX process uses high temperatures (approximately 200 °C/400 °F) and high pressures (10-35 bar/150-500 psi) to facilitate the leaching process.
After the autoclave processing step, the slurry is returned to atmospheric condition by taking it through two or more flashing letdown stages.
Once at atmospheric condition, the slurry is washed and separated, at which point the metal can be recovered from the liquid portion in the downstream processing circuits.