Recovery of rare-earth elements from obsolete fluorescent lamps

• Grant number: 22/16500-1
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: February 01, 2023
• End date: October 11, 2024
• Field of knowledge: Engineering - Chemical Engineering
• Principal Investigator: Denise Crocce Romano Espinosa
• Grantee: Luan Matheus da Silva Alvarenga
• Host Institution: Escola Politécnica (EP). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Associated research grant: 19/11866-5 - Development of innovative processes for the recovery of critical metals, AP.TEM
• Associated scholarship(s): 23/15490-5 - Recovery of yttrium from obsolete fluorescent lamps, BE.EP.IC

Abstract

The use of rare earths elements has intensified in recent decades with the advances in technology. The applications of these elements stand out in the areas of electronic information, metallurgy, petrochemical industry, energy and environment, and national defense. The main issue when mining rare earth elements lies in their low concentration in the ores. Thus, the mining process becomes more expensive and sometimes commercially unviable. Therefore, recovery from urban waste can become a viable alternative. One of the advantages of regaining rare earths from urban waste is that the formation of radioactive by-products associated with mining, such as thorium and uranium, can be avoided. Among the devices that have one or more rare earth elements in their composition are fluorescent lamps. The phosphor layer present in lamps corresponds to approximately 3% of the total lamp components. This phosphor powder fraction is rich in europium, terbium and yttrium. The amount of rare earth elements in phosphor powder is between 10 and 20%, which is higher than the fraction present in the ore. This paper is proposed to study the elements present in fluorescent lamp powder in order to determine qualitatively and quantitatively the fractions present with the focus on the rare earth elements present in this device. In addition, after characterization, to evaluate fractioning routes of rare earth elements aiming the recovery of metals. Finally, the solvent extraction technique will be evaluated to recover the rare earths.