How does heating electrolytic chromium with carbon lower its oxygen content?

Electrolytic chromium typically contains approximately 0.5 percent oxygen, which is often too high for certain industrial applications. To reduce this oxygen content, the chromium is combined with carbon and the resulting briquettes are heated to 1,400 °C (2,550 °F) under a vacuum of 13 pascals.1

This process effectively lowers the oxygen content to 0.02 percent, resulting in a metal with a purity level exceeding 99.9 percent. The reduction of oxygen through heating with carbon is a critical step in chromium processing to achieve the high-purity metal required for specialized uses.1