Rare earth recovery from Urban Mines: Recycling of luminescent powder from fluorescent lamps By Thomas Langer OSRAM AG
Agenda Page 1. Introduction 2. Fluorescent lamp recycling and the material circle 3. Urban Mining 4. How does the recovery work? 5. Summary 3 5 8 10 14 Electronic Recycling Asia 09.03.2012 Page 2
1. Introduction Recycling of rare earth elements Important rare earth oxides for the lighting industry The oxides of the rare earth elements Cerium, Europium, Lanthanum, Terbium and Yttrium are the most important ones for the lighting industry, respectively OSRAM. This is because they are needed to produce the phosphor mix contained in fluorescent lamps. Phosphor is the white powder on the inside of the lamp that converts ultraviolet light into visible light. In fact, the oxides of the above-mentioned rare earth elements are responsible for the creation of red, green and blue light. As the graphic below illustrates, the combination of these lights makes it possible to generate a natural and pleasant white light. Electronic Recycling Asia 09.03.2012 Page 3
1. Introduction Recycling of rare earth elements To OSRAM, the recycling of rare earth elements and their chemical compounds has been an important issue for a long time. The company started first research on this topic in 1985. In 2004, efforts were reinforced and a project was launched to find an industrially viable method for the recovery of rare earths from fluorescent lamps. After two years, the research results led to a patent application. Electronic Recycling Asia 09.03.2012 Page 4
2. Fluorescent lamp recycling and the material circle Fluorescent lamps construction and composition, principal of operation Fluorescent lamps are gas discharge lamps that use mercury vapors to produce light. The inside of the tube is coated with a thin layer of triband luminescent powder containing rare earth. Mercury is added in the manufacturing process for conversion of electrical energy into radiant energy. The inner coating layer absorbs the UV energy causing visible light. The composition of the luminescent powder is responsible for the light s color and intensity. Electronic Recycling Asia 09.03.2012 Page 5
2. Fluorescent lamp recycling and the material circle What does recycling mean for the material flow? Fluorescent lamp recycling When WEEE came into force 2002, lamp recycling became a major factor for the lamp production. Glass was the first material that was brought back into the circle in order to produce new tubes. Apart from the glass also Aluminum got back to the industry as a new raw material for lamp bases. Recently also the fluorescent powder became reusable. That means an almost closed material loop of fluorescent lamps. Releases of Mercury into the environment are correlated with the processing and the disposal methods of spent fluorescent lamps. Considering the environmental implications, the recovery of contained Mercury is very important. Electronic Recycling Asia 09.03.2012 Page 6
2. Fluorescent lamp recycling and the material circle Lamp recycling equipment Electronic Recycling Asia 09.03.2012 Page 7
3. Urban Mining What is urban mining? The process of reclaiming compounds and elements from products, buildings and waste. (via urbanmining.com) To explain that better, let s take a look at an example, where the principle of urban mining applies: Rare Earth Luminescent powder from the recycling of fluorescent lamps is the ideal source of rare earth elements for lamp manufacturers like OSRAM. The fluorescent powder contains all rare earth elements needed to make new fluorescent powder. The ratio of rare earth elements fits optimal to the fluorescent powder composition used in fluorescent lamps. Electronic Recycling Asia 09.03.2012 Page 8
3. Urban Mining How does urban mining work? That doesn t mean, we are going dumpsite diving! No, it s much easier!! Lamp recycling before waste deposit is basically the source we are talking about. Europe for example has already established quite a good collection system of end of life lamps. All those lamps are treated in recycling plants and are separated into the different fractions like glass, aluminum, fluorescent powder and others. The recycled powder is now the material we would like to take a deeper look into. Electronic Recycling Asia 09.03.2012 Page 9
4. How does the recovery work? Where does the recycling powder come from? Our sources are recycling plants all over the world in Europe, USA, Asia und other countries OSRAM collects the powder and transports it to its facilities in Germany Our own production shrinkage gets collected, too. Europe: OSRAM works together with the collection and recycling schemes in all countries single recyclers Other Countries: In many other countries outside Europe OSRAM has contracts with recyclers. A complicated part is the bureaucracy of transboundary waste shipment of these powders. Electronic Recycling Asia 09.03.2012 Page 10
Rare Earth Recycling: Basic Steps Electronic Recycling Asia 09.03.2012 Page 11 Recycling Powder consists of 1. Triband Phosphor (1% - 30%) 2. Impurities a) Glass Dust (40% 80%) b) Halophosphate Phosphor (20% - 40%) c) Organic Impurities (0,1% - 1%) d) Other Metals (0,1% - 1%) e) Mercury (0,01% - 1,5%) Triband Phosphors from EoL lamps can t be reused directly and have to be decomposed into single RE via Extraction removal of impurities (glass, halophosphate, Hg,..) discomposing of triband phosphors and production of synthetic RE ore Separation separate heavy RE elements from each other in high purity grade (99,99%) and produce precursors for the phosphor synthesis
4. How does the recovery work? The OSRAM patent (German patent 2007; US-American patent 2011) The OSRAM Patent includes 6 steps Mechanical separation of coarse components Separation of the Halophosphate phosphor Extraction in acids of easily soluble rare-earth fluorescent substances (mainly Y, Euoxide) Extraction in acids of rare-earth fluorescent substances which dissolve with difficulty (e.g. rare-earth phosphates) Breakdown of the remaining components which contain rare earths (e.g. rare-earthaluminates) Final treatment results in a synthetic ore of all rare earth elements. Mechanical separation of coarse components: This basically includes the mercury removal and sieving to remove glass and other impurities. The distilled mercury is being reused too. Electronic Recycling Asia 09.03.2012 Page 12
4. How does the recovery work? Separation of the synthetic ore into single rare earth oxides The most commend technique is the liquid - liquid extraction. There are different systems, but all of them are able to separate the synthetic ore into single rare earth oxides. The most difficult rare earth elements for processing are the so called heavy rare earths like Terbium and Yttrium. But all are essential for fluorescent lamps. Europium is a typical rare earth element which is only used in the lighting industry. Out of the rare earth oxides, fluorescent powder components for new lighting powder are produced. Yttrium / Europium for red color Cerium, Lanthanum and Terbium for green color Europium for blue color Electronic Recycling Asia 09.03.2012 Page 13
5. Conclusion / Summary Recycling of luminescent powder from fluorescent lamps is really sustainable Fluorescent lamps are by themselves already Green Lighting Products as they are highly efficient light sources. In combination with the recently developed recycling of fluorescent powder and mercury it becomes even more a Green Product! More than 90% of the material used in a fluorescent lamp is recovered within the recycling circle! RE Recycling prevents RE Phosphor land filling and thus reduces the demand on natural sourced RE oxides! Electronic Recycling Asia 09.03.2012 Page 14
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