(Alexandra Eberle & Cheyenne Lea Henzelmann)
Rare earth elements
Rare earth = 17 metals --> same chemical properties:
physical properties --> very different
e.g. react magnetically under UV light.
Occur in many places in the earth's crust. Minerals monazite & bastnäsite contain several SEM occurrences above 1% --> rare, therefore "Rare Earth".
Largest deposits in China, Brazil and USA. Originally waste products from extraction of other metals. Today mined for high-tech industry.
Extraction:
Use of acids --> formation of radioactive waste. This makes mining expensive. Low environmental regulations and cheap labor --> development mass production (China) 2010 approx. 98% of SEM production (worldwide) from China. Export restriction kept world market prices high.
Different reactions of the industry:
Mines newly opened or reopened
Industrial processes developed --> raw materials in demand to be obtained by recycling --> e.g. magnets
Consumer side has reduced use of SEM --> replacement by alternative materials.
Rare earth elements