METHOD FOR INDIVIDUAL RARE EARTH METALS RECYCLING FROM FLUORESCENT POWDER E-WASTES

• Main Authors: PATIL, Ajay Bhagwan, LUDWIG, Christian, STRUIS, Rudolf P. W. J, SCHULER, Albert Josef
• Format: Patent
• Language: English; French; German
• Published: 24.02.2021
• Subjects: ADHESIVES; CHEMISTRY; DYES; FERROUS OR NON-FERROUS ALLOYS; MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FORELSEWHERE; METALLURGY; MISCELLANEOUS APPLICATIONS OF MATERIALS; MISCELLANEOUS COMPOSITIONS; NATURAL RESINS; PAINTS; POLISHES; PRETREATMENT OF RAW MATERIALS; PRODUCTION AND REFINING OF METALS; TREATMENT OF ALLOYS OR NON-FERROUS METALS

A robust and economically viable process technology is developed for the recycling of critical rare earth (REEs) metals from end of life lamp fluorescent powder (FP) e-waste. This is one of the first efforts to recycle invidual pure REEs from municipal e-waste components to arrive at commercially promising individual REEs purity, which are knowingly difficult to separate from wastes. The process technology addresses the management of strategically important REEs resources relevant for green energy and smart/hybrid technology. The methodology involves cheap mineral acid for near quantitative RE metal sequential digestion and extractive (liquid-liquid) separation protocols using the selective extractant ligand molecules and hydrometallurgical process conditions to separate Y, Eu, and Tb, to more than 99% purity and Gd, La and Ce to elevated purities each from the metal digested FP waste fractions. The developed technology has potential for scale up on industrial scale, re-use of extractant and organic phase as well as extended use for recovering RE metals from other e-waste after optimizations. The process can be employed to REE mixtures from e-waste as well as mining tailings origin. The process has the advantage over inseparable combined digested phosphor fractions as well as over inefficient leaching of Tb from LAP phosphor. It is also one of the first attempts to achieve the individual purity of rare earths raw materials from such a complex waste streams. The novel approach proposed herein with judicial choices of extractants and inventive steps of process hydrometallurgy will help to tap potential in e-waste secondary resources.