Patent ID: 6994219

Claim:
A method for separating a particulate feed comprising a first particle type and a second particle type, the method comprising the steps of providing a separation apparatus comprising a separation vessel having a top and a bottom, wherein the separation vessel includes inwardly sloping side walls with a greater spacing between the side walls at the top of the separation vessel than at the bottom of the separation vessel, and a magnet structure having a first pole positioned exterior of and adjacent to each of the side walls of the separation vessel, and a second pole positioned above the separation vessel; thereafter introducing a mixture of the particulate feed and a ferrofluid into the separation vessel; and thereafter permitting the particulate feed to separate into a first particle fraction comprising more of the first particle type than the second particle type, wherein the first particle fraction sinks in the ferrofluid of the separation vessel, and a second particle fraction comprising more of the second particle type than the first particle type, wherein the second particle fraction floats in the ferrofluid of the separation vessel away from the side walls of the separation vessel.