Nickel: smelting, producing-Metalpedia
The resultant carbon monoxide is re-circulated and reused through the process. The highly pure nickel produced by this process is known as "carbonyl nickel". Source: Nickel-Wikipedia; Hydrometallurgy of Nickel; The high temperature (~250°C) acid pressure leaching of nickeliferous laterite ore has been practised commercially since the late 1950's.