Problems and prospects of waste processing and recycling of production containing rare earth metals

Abstract

The demand for rare-earth metals (REMs), which are quite expensive and scarce resources, is constantly growing and there is a shortage of supply for individual metals. All this makes the task of the search for new sources of REMs, inclu-ding man-caused ones, very important. In solving these problems, a very promising direction is the development of REM recycling schemes, both directly from the wastes of the production of rare metals and other industries, and from the goods that have served their time, or in other words, the so-called end-of-life (EOL) goods. This direction of recycling seems to be the most efficient, reasoning from the volumes of REMs that pass to wastes in EOL goods, among which REM recycling from NdFeB magnets of electronic devices, fluorescent lamps, nickel-metal hydride (NiMH) batteries, and a number of other RE-containing products has become predominant. For example, the degree of REM recovery in the recycling of magnets is 80–95%; such a volume of secondary resources of rare earths is of serious commercial interest. As experts are assessing, the level of recycling of rare earths from fluorescent lamps will be ~95%, and it will be possible to recycle the lamps for another 30 years. When processing nickel-metal hydride (NiMH) batteries, up to 80% of REMs contained in them is returned to the commercial circulation. Another important direction of obtaining REMs is the disposal of industrial wastes. Such technologies can be developed in the countries where REM products with high value added are not manufactured, however, there are mineral resources and advanced industry. For example, in Russia, such technologies are used at the Solikamsk Magnesium Works, which produces rare-metal production from loparite concentrate. At the Russian Rare Metals plant, there has been developed a technology for processing grinding wastes from the production of permanent magnets based on rare-earth metals, from which the high-purity compounds of neodymium, praseodymium, and dysprosium can be obtained. Another technogenic resource for the development of REM recycling technologies in Russia are considerable, over 250 million tons, phosphogypsum wastes from the processing of Khibiny apatite concentrate. The Skaygrad Group has developed a technology that allows to obtain from 500 to 2000 tons of a sum of 17 rare-earth metals per year, with a total mass quota up to 99.5% of REMs. In general, it can be concluded that the technologies of REM recycling from both end-of-life goods and products, and industrial wastes will continue to develop not only in the countries of the Asia-Pacific region or EU, but also in Russia in spite of relatively low content of rare earths in them.