
Valves and pumps for gold autoclave pressure oxidation
Process reliability and productivity
Autoclave pressure oxidation (POX) is an effective pre-treatment option when extracting gold from refractory ore bodies, such as pyrite and arsenopyrite. While gold processing plants are the most common utilizers of POX technology, the process can also be applied to other metals, like copper, zinc and uranium. Valmet has a wide range of valves, pumps and services for POX process.
Benefits
Higher recovery rates and lower total cost of ownership
Over a century of experience in the mining sector
Higher resistance against abrasive media, corrosion and erosion
400+ service professionals in over 40 countries around the world
Valves and pumps control various flows in gold autoclave pressure oxidation process
Autoclave POX operations include several different types of valves to control both liquid and gaseous flows. Slurry feed and discharge valves, pump isolation valves, depressurization valves, steam supply and steam drum isolation valves, as well as oxygen feed valves, among others, make sure that the POX process works optimally and efficiently.
In the autoclave, valves are subjected to a high-temperature and an oxygen-rich environment, so the right selection of valves can potentially make a significant positive impact on the operation’s reliability.
Valves and pumps for slurry feed
The conditions that valves and pumps face in the POX process require the highest possible resistance against corrosion and erosion as well as against the deterioration caused by solids. The right material, seat and coating choices play an important role in maintaining the sealing abilities of slurry feed valves and pumps.
Valves for oxygen feed
Valves for depressurization
Valve and pump products and services
Autoclave POX for the extraction of refractory gold
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.
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