Poling is a refining step where a reducing agent is introduced into a bath of liquid copper oxide. Traditionally, workers shoved green wood logs into the melt, which released steam and reducing gases to strip away the oxygen. Current industrial practice achieves the exact same chemical result by injecting natural gas or ammonia directly into the furnace. This prevents the formation of cuprous oxide networks that would make the final metal brittle.
Heard on the job
Keep the gas flowing and pole this batch a bit longer, the oxygen levels are still running high on the analyzer.
Insider tip
If you leave the reducing agent in too long, you can overpole the copper, causing it to absorb hydrogen and become porous when it solidifies.
Also heard as
- poling