Rare earth elements are essential for use in modern technology and are key components in most electronic products. Despite the importance of rare earth elements, only about 1% of them are recovered from the final product, and the rest is converted into waste.
There have been recent challenges in developing efficient rare earth element recovery processes. This article will discuss different methods of recovering rare earth elements and show that it is possible to recover rare earth elements from waste to make permanent magnets.
Application of rare earth elements:
Rare earth elements, also known as rare earth metals, are a group of 17 different elements, each with a characteristically similar physical characteristic: silvery-white soft heavy metals. Scandium and yttrium are also rare earth elements because they are found in the same deposits as most lanthanides and exhibit similar chemical properties, but differ electronically and magnetically. Each rare earth element has various applications and uses.
Here are some of their applications:
1. Scandium alloys are used in the manufacture of aerospace components and radioactive heat tracers in oil refineries.
2. Yttrium is used in the manufacture of camera lenses and refracting telescope lenses.
3. Promethium is used to make car batteries.
4. Samarium is used in the manufacture of lasers, neutron capture, and control rods in nuclear reactors.
5. Other applications of rare earth elements include the manufacture of hard disk drives, magnets, X-ray machines, metal halide lamps, fiber optic technology, LED light bulbs, etc.
Waste that may contain rare earth elements
Rare earth elements are emerging pollutant that poses a risk to the environment due to their increasing use in different technological applications. E-waste remains a significant source of rare earth element pollution. This is because e-waste contains high concentrations of rare earth elements, which are often disposed of in unsafe ways and are harmful to the environment.
Recycling of rare earth elements:
Rare earth metals are very critical components present in different consumer products such as permanent magnets, electric vehicles, smartphones, etc. It occurs naturally in the ore as a mixture and must be purified before use. Rare earth elements are expensive to mine, so it is cheaper to recycle rare earth elements that have been processed into materials. Despite their ability to be reused, rare earth-containing products are only used once and discarded. Recycling rare earth elements will provide manufacturers with a steady supply of rare earth metals while reducing waste and the significant environmental burden it creates. E-waste is a major source of rare earth elements.
Recent advances in recycling technology have made it more feasible to extract rare earth elements from these materials. For example, Japan has some recycling plants in operation, and an estimated 300,000 tons of rare earth metals are stored in unused electronics. Also, in France, efforts are underway to build two factories that will produce 200 tons of rare earth metals a year from second-hand fluorescent lamps, batteries, and magnets. In addition, coal and by-products are potential sources of key elements, including rare earth elements estimated to yield about 50 million tonnes of rare earth elements.
Rare earth element recovery method:
Developing an effective and economical strategy for REE recovery depends on different factors, including commodity prices, size of deposits, disposal costs, and potential hazards.
Methods for recovering rare earth elements from waste electronics in most developed countries are:
1. The gadget is chopped and ground into powder form, from which the basic components, the rare earth elements, are extracted.
2. Pyrometallurgical methods separate electronic waste by heating elements to very high temperatures. This method requires a lot of energy.
3. Liquid-liquid extraction is another common method in use today. In this method, the waste is dissolved in strong acid and then rare earth is extracted using a range of solvents.
Uses of recycled rare earth elements:
The use of recycled rare earth elements has increased. Most rare earth elements are used in the production of catalysts and magnets. Rare earth elements are critical in the production of high-performance magnets, alloys, glass, and electronics.
The manufacturing method of rare earth magnet:
Recycled rare earth elements can be used to make rare earth magnets. Rare earth magnets are strong permanent magnets made of rare earth element alloys. They are the strongest permanent magnets, producing stronger magnetic fields than other types of magnets.
Rare earth magnets such as neodymium magnets are mainly manufactured by powder metallurgy process. In this method, a suitable composition is pulverized to a fine powder, compacted, and heated by "liquid phase sintering" to induce densification. Permanent magnets such as ferrite, samarium cobalt (SmCo), and neodymium iron boron magnets are made this way. In conclusion, rare earth elements recovered from waste can be used to make permanent magnets.
