Recovery of Co²⁺ Ions from Aqueous Solutions by Froth Flotation. Part II. CoS Precipitation

Abstract

Cobalt ions have been recovered from aqueous solutions by dispersed-air flotation in acidic conditions. The preliminary step of precipitation as cobalt sulfide using Na₂S is kinetically limited, with only approximately 70% of the cobalt ions being recovered. Recoveries increase considerably under alkaline conditions, where Co(OH)₂ is also precipitated. Several collectors have been tested: cetyl trimethyl ammonium bromide, sodium dodecyl sulfate. cetyl pyridinium chloride, and dodecylamine; dodecylamine was found to be the most efficient. The gas flow rate was found to affect the process, with a flow rate corresponding to a superficial gas velocity of 0.1 cm/s yielding maximum recoveries; any further gas flow rate increase resulted in lower recoveries. An increase in column height was found to have an adverse effect on CoS recovery.

Key Words:

• Precipitate flotation
• umn flotation
• alt ions