Patent ID: 7976798

Claim:
A method for recovering rare earths from lamp waste A which contains a plurality of fluorescent materials which comprises halophosphates and rare earth fluorescent material, wherein the method comprises the following sequence of method steps: a) a mechanical treatment step, wherein the lamp waste A is treated to remove coarse constituents A′ to leave a solid starting material A″ which comprises rare earth containing fluorescent material; b) an extraction step to extract halophosphates, wherein the solid starting material A″ undergoes a cold acid leaching to produce a liquid filtrate B′ and a solid residue B″, wherein B′ contains waste material comprising halophosphates and B″ comprises rare earth compounds; c) an extraction step to extract rare earth compounds, yet insoluble in step b), yet soluble in acids, wherein the residue B″ undergoes a hot acid leaching to produce a liquid filtrate C′ and a solid residue C″, wherein C′ contains rare earth compounds soluble in acids and solid residue C″ contains as yet insoluble rare earth compounds; d) an extraction step to extract rare earth compounds yet insoluble in step c), wherein the residue C″ undergoes intensified hot acid leaching to produce a liquid filtrate D′ containing rare earth compounds and a solid residue D″ containing rare earth compounds; e) a digestion step by way of alkaline or acidic digestion to digest remaining compounds containing rare earth material, yet insoluble in step d), wherein the solid residue from step d) is digested to produce a liquid filtrate E′ containing rare earth containing material and a solid waste residue E″; f) a final treatment step to precipitate rare earth material wherein the liquid filtrates C″, D′ and E′ are each treated to recover the rare earths as precipitates.