Recovery of Rare Earth Metals

About

Background and Basic Concept of the Technology The long-term power shortages that are being experienced in South Africa have meant that Eskom has initiated a number of campaigns to save energy and thereby reduce the pressure being placed on the power generation capabilities of the country. One of these campaigns is the replacement of incandescent light bulbs with compact fluorescent light (CFL) bulbs. The CFL bulbs contain small amounts of mercury, which is toxic. At present, the ‘burnt out’ bulbs, that are collected, are disposed of in hazardous waste landfill sites, as no recycling operation exists in South Africa. The disposal of the CFL bulbs in these hazardous waste landfill sites is an expensive alternative to recycling. Apart from the bulbs that are collected, an even larger portion of the waste CFL bulbs that are generated in South Africa are incorrectly sent to ordinary landfill sites, where the water soluble mercury enters into the groundwater. A novel process was developed for the recovery of rare earth metals (yttrium oxide and europium oxide at present) from the luminophorous powder used in the CFL bulbs. The sale of the rare earth metals that are recovered from the CFL bulbs makes the recycling of CFL bulbs a viable business opportunity. A semi-commercial pilot plant has been designed using this process, and has been constructed at the University of KwaZulu-Natal. Alongside recovery of the rare earth metals, the pilot plant also converts the harmful elemental mercury that is present in the luminophorous powder into mercury sulphide, which occurs naturally and is non-toxic. The process that is used for the recovery of the rare earth metals is a novel process, and it is a first in the world for the recovery of rare earth metals from used CFL bulbs. Applications & Market Opportunities Rare earth elements play an important role in a number of industries, particularly the high tech and green energy sectors where properties such as robust performance, durability and low carbon emissions are important. In some applications, rare earths do not have any effective substitutes and are important to the particular manufacturing process. Rare earths are used in a variety of modern technologies with applications in the military, medical, scientific, aerospace and consumer sectors plus in the increasingly important "green" sector. Therefore, the industry drivers and markets are as equally diverse. The presence of mercury in the CFLs means that the disposal of the CFLs in landfill sites is not an environmentally viable option, due to the subsequent mercury emissions. Other means of disposing of the CFLs therefore need to be developed. With the rapid increase in the price of these rare earth metal oxides, it has become a viable option to recycle the rare earth metal oxides from CFLs alongside the glass, mercury and other components. Up until now, the glass and mercury have been recovered from the CFLs, with phosphorescent materials being sent to landfill sites. Stage of Development Pilot plant has been built at the University of KwaZulu-Natal, Howard College. Intellectual Property Status South African Patent (2013/02663). Collaboration Sought Industry Partner/Funders.