A comprehensive review on Y and Eu recovery from cathode-ray tube phosphors

Phosphors are essential components in lamps and monitors and major users of rare earths elements (REE) yttrium and europium. The use of cathode-ray tubes (CRTs) in monitors is declining worldwide as more efficient technologies emerge. Consequently, this sort of electronic waste accumulates untreated in recycling companies and warehouses. This review first provides an overview of the dismantling techniques used to collect CRT phosphors. Next, recycling processes of Y and Eu mixtures obtained from CRT phosphors are addressed, with particular focus on fundamental chemistry. Among the leaching approaches developed, some include high temperature pre-treatment, although most rarely improve REE recovery or selectivity. Separation approaches addressing REEs retrieving from leach liquors are not abundant in literature. However, some contributions employing phosphorated extracting agents revealed to efficiently produce REE-rich solutions with minimal contamination and will therefore receive more attention. Chemical precipitation is often applied thereafter to isolate REE-rich products, used as a less expensive method to obtain a less pure REE oxide in a first isolation step. Process optimisation, required for scale-up, is missing in most processing stages, and should deserve more attention from the research community. Also, sustainable recycling routes are scarce and should be explored in the future to improve sustainability.