Processing Coal Wastes

—The processing of coal waste is considered. There is a clear need to increase the recycling of coal waste in Russia, on the basis of innovative technology. The content of nonferrous metals, rare metals, and rare-earth metals is analyzed at three levels: in coal; in coal ash, coal slag, and cake; and in fly ash and cake ash. The concentrations of some noble metals (silver), rare metals (cadmium, selenium, titanium, rubidium, and tantalum), and rare-earth metals (lanthanum, neodymium, and gadolinium) are found to be close to the values recommended for further evaluation in coal. Elevated concentrations in coal waste are noted for other metals: molybdenum (nonferrous metal), lithium, niobium, germanium, and scandium (rare metals); and praseodymium, yttrium, ytterbium, and samarium (rare-earth metals). The need to extract valuable metals from coal waste is confirmed, especially for fly ash and cake ash. Price analysis of rare and rare-earth metals establishes that their extraction from coal waste is promising. The case is made for assessing the overall impact of processing coal waste, taking account of economic, social, environmental, and indirect effects. By comprehensive processing of coal waste, metal concentrates and associated products may be derived on the basis of innovative methods.