Sustainable Processes Development for Recycling of Fluorescent Phosphorous Powders - Rare Earths and Mercury Separation

Research Project, 2011 – 2014

During a full PhD student time we will investigate, chemically and technically processes for removal of mercury and recovery of valuable or toxic metals from flourecent powders from spent lighting appliances. The processes are primarily based on leaching of the metals from the first mechanical treatment step. The base for mercury removal and metal recovery from this mixture are, firstly, to make land filling possible and secondly to make it possible to reinsert the valuable metals in the industrial production cycles. Based on previous results the investigation will be focused on: mechanical separation of macro fractions; metals leaching from the phosphorous mixture; their solvent extraction and mercury separation. Mercury content in the macro fraction will be carefully monitored. Important milestones are: 1. Optimization of the leaching for different batches of homogenous mixtures and investigation on how different compositions and metal species affect the leaching; 2. Development of the solvent extraction systems for important metals; 3. Proof of concept by setting up a lab scale separation process based on mixer settlers. During the project a continous feed back from the industry is expected thus making it possible for them to make a pilot scale process shortly after the finalisation of the project. The project is planned to be carried out as a cooperation between research groups at Chalmers , Chalmers Industriteknik, IVL and Nordic Recycling AB.