How are cobalt arsenide ores treated to remove arsenic?

To treat cobalt arsenide ores and remove arsenic, the concentrates are typically processed using one of two primary methods:

• Roasting: The ores are roasted under controlled conditions, similar to the process used for sulfide concentrates. This procedure effectively removes the arsenic by converting it into an impure arsenic trioxide.1
• Leaching and Precipitation: Alternatively, the concentrates can be leached. Following this, the cobalt is recovered through precipitation using hydrogen, a technique also utilized for nickel sulfide concentrates.1

These processes are essential for handling primary cobalt ores, which include arsenides such as smaltite, safflorite, and skutterudite, as well as the sulfoarsenide cobaltite.2