Rare earths are a group of special chemical elements which, when used in small quantities, are the " vitamins " essential to the development of new technologies, particularly green technologies. For example, they are used in high-performance magnets (for electric vehicles, off-shore wind turbines), and in pollution control systems for petrol and diesel vehicles (catalytic converters and soot removal systems). They are also used in energy-saving lighting systems (lamps known as " low consumption " and LEDs), or medical examination devices (MRI - Magnetic Resonance Imaging, and PET Scan - Positron Emission Tomography). Rare earths are - for the most part - relatively abundant. Nevertheless, their exploitation, from ore to the industrial production of "usable" material, requires a high level of technical expertise and substantial investment. To illustrate this, we'll take the example of the industrial development of luminophores. Luminophores are the "active" elements of the light-emitting system, and are today mainly used in lamps (fluorescent lamps, LED lamps) and screens (plasma screens and LCD backlights).
First, we'll look at the issues involved in extracting and separating rare earths, as well as the technical solutions implemented, including new recycling processes. Next, we'll look at the synthesis of advanced phosphor materials, explaining the steps involved at each scale, from research laboratory to industrial production. Historical examples will highlight the key luminophores that made technological breakthroughs possible, such as the first color cathode ray tube displays, the most efficient fluorescent lamps, or high-light-quality LED lamps.
