Patent ID: 7624877

Claim:
A flotation device including: a sequence of at least two flotation tanks arranged relatively as an upstream tank and a downstream tank, each of said tanks being adapted to receive slurry incorporating fine and coarse particles containing minerals to be extracted, and each of said tanks including: a feed inlet for admission of slurry; agitation means to agitate the slurry; aeration means to aerate the slurry whereby floatable minerals in suspension float upwardly to form a surface froth; an overflow launder for removal of the surface froth; and a bottom outlet for withdrawal of relatively coarse or dense components of the slurry; wherein the bottom outlet from the upstream tank is connected to the feed inlet of the downstream tank whereby a relatively dense fraction of the slurry including a relatively high proportion of coarse or dense components is withdrawn from the upstream tank and fed directly to the downstream tank for reprocessing in the downstream tank; and wherein at least one of said tanks includes an upper side outlet adapted for withdrawal of a relatively fine fraction of the slurry including a relatively high proportion of fine or lower density components for separate size processing independently of the upstream and downstream tanks.