3 ms·

Canon develops quantum dot OLED materials without rare metals

12 points by benkan 3y ago

vinnyvichy 3y ago
This is misleading. They use (toxic) lead in place of rare earths. Lead has a reputation of being common and rare earths have a reputation of being uncommon, but the following chart shows that rare earths are actually as common as lead. https://upload.wikimedia.org/wikipedia/commons/0/09/Elemental_abundances.svg https://upload.wikimedia.org/wikipedia/commons/0/09/Elementa... It is cheaper to extract and process lead but that is not what is suggested by the headline
- adrian_b 3y ago
  Among the so-called rare-earth elements only cerium, lanthanum and neodymium have abundances in the Earth's crust (where they are highly enriched) that are comparable to lead, but the cost in energy and materials needed for their extraction, processing and recycling is many, many times greater than for lead. However here the news is about indium, which is one of the rarest chemical elements and for which alternatives are needed for most uses as its reserves are insufficient. In the Solar System, indium is less abundant than gold. In Earth's crust indium is enriched, but it still remains only about as abundant as silver. The right strategy with toxic elements like lead, mercury, cadmium and thallium is not to forbid their use. The real goal is to forbid their release back into the environment after their extraction. It is impossible to avoid their extraction because in mines they are mixed with other very desirable elements. If they are not separated, because the mine owners cannot sell them, they remain in mining waste, causing a pollution much more severe than from any industrial products. So if the use of such elements would be completely forbidden, the only method to make it really work would be if the governments would buy all the quantities of such elements that result as byproducts of mining operations and they would store them in safe places. Because these toxic elements can nonetheless be very useful for certain purposes, a more rational alternative to just store them is to allow their use for various applications, conditioned by a license that should be granted only if the applicant convincingly demonstrates that the toxic element will not be released from the product during its lifetime and that there exists a recycling process that can recover the element from the product at a certain efficiency, e.g. 95% (and the selling price should include the recycling cost, possibly also a deposit refundable on return to a recycling center, to guarantee that the products are not dumped randomly at end of life).
- jcarrano 3y ago
  How much do they use and how easy is it to recycle? For example, lead in lead-acid batteries can be completely recycled.

12 points by benkan 3y ago

This is misleading. They use (toxic) lead in place of rare earths. Lead has a reputation of being common and rare earths have a reputation of being uncommon, but the following chart shows that rare earths are actually as common as lead. https://upload.wikimedia.org/wikipedia/commons/0/09/Elemental_abundances.svg https://upload.wikimedia.org/wikipedia/commons/0/09/Elementa... It is cheaper to extract and process lead but that is not what is suggested by the headline

adrian_b 3y ago
Among the so-called rare-earth elements only cerium, lanthanum and neodymium have abundances in the Earth's crust (where they are highly enriched) that are comparable to lead, but the cost in energy and materials needed for their extraction, processing and recycling is many, many times greater than for lead. However here the news is about indium, which is one of the rarest chemical elements and for which alternatives are needed for most uses as its reserves are insufficient. In the Solar System, indium is less abundant than gold. In Earth's crust indium is enriched, but it still remains only about as abundant as silver. The right strategy with toxic elements like lead, mercury, cadmium and thallium is not to forbid their use. The real goal is to forbid their release back into the environment after their extraction. It is impossible to avoid their extraction because in mines they are mixed with other very desirable elements. If they are not separated, because the mine owners cannot sell them, they remain in mining waste, causing a pollution much more severe than from any industrial products. So if the use of such elements would be completely forbidden, the only method to make it really work would be if the governments would buy all the quantities of such elements that result as byproducts of mining operations and they would store them in safe places. Because these toxic elements can nonetheless be very useful for certain purposes, a more rational alternative to just store them is to allow their use for various applications, conditioned by a license that should be granted only if the applicant convincingly demonstrates that the toxic element will not be released from the product during its lifetime and that there exists a recycling process that can recover the element from the product at a certain efficiency, e.g. 95% (and the selling price should include the recycling cost, possibly also a deposit refundable on return to a recycling center, to guarantee that the products are not dumped randomly at end of life).
jcarrano 3y ago
How much do they use and how easy is it to recycle? For example, lead in lead-acid batteries can be completely recycled.