Methods of recovering rare earth elements from a material

A method of recovering rare earth elements from a rare earth-containing material comprises contacting the rare earth-containing material with a solution formulated and configured to dissolve rare earth elements from the rare earth-containing material and form a solution including a plurality of rare earth elements dissolved therein. The method further includes exposing the solution including the plurality of rare earth elements dissolved therein to one of a liquefied gas or a supercritical fluid to isolate the rare earth elements from each other. Related methods of removing and purifying rare earth elements from materials and phosphor lamps are also disclosed.