RECOVERY OF CO2-SOLUTIONS BY FROTH FLOTATION .2. COS PRECIPITATION( IONS FROM AQUEOUS)

Cobalt ions have been recovered from aqueous solutions by dispersed-ai r flotation in acidic conditions. The preliminary step of precipitatio n as cobalt sulfide using Na2S is kinetically limited, with only appro ximately 70% of the cobalt ions being recovered. Recoveries increase c onsiderably under alkaline conditions, where Co(OH)I is also precipita ted. Several collectors have been tested: cetyl trimethyl ammonium bro mide, sodium dodecyl sulfate, cetyl pyridinium chloride, and dodecylam ine; dodecylamine was found to be the most efficient. The gas flow rat e 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 incre ase in column height was found to have an adverse effect on CoS recove ry.