RARE EARTH METALS LEACHING FROM COAL ASH AND THEIRS CONCENTRATION
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Abstract (English):
Problems related to rare earth metals leaching from coal ash and theirs ion-exchange concentration from sulfuric solutions, in particular the characteristics of scandium, yttrium and lanthanum sorption by different ion exchange resins have been considered in this work. It has been shown that the best way to leach rare earth metals from coal ash is a complex acid and biological treatment of ash waste. Kinetics related to the process of scandium, yttrium and lanthanum acid leaching from ash and slag waste of CHPP in Kumertau has been investigated. Subsequent metal solutions concentration was achieved using ion exchange resins. The results of experimental studies related to the processes of rare-earth metals (in particularly scandium) ion exchange concentration by cation exchange resin in the Naform PC-100 have been presented, as well as the results of experimental studies related to rare earth metals (scandium including) sedimentation process, using special sedimentators. Dependences of rare earth metals (in particular scandium) sedimentation efficiency against pH value have been constructed, and recommendations for pH values, that are optimal for rare earth metals sedimentation, have been given. Based on obtained experimental results it was created and tested an experimental laboratory prototype of plant for rare earth metals (scandium, yttrium and lanthanum including) extraction from located near Moscow brown coal basin’s slag heaps, and from ash dumps of Russian Federation’s energy enterprises. This plant’s process flow diagram as well as its operation description has been presented. The created plant was tested in modes previously fulfilled in laboratory conditions. At the same time, carried out integrated exploration have showed the prospects for implementation of developed technical solutions for processing of ash dumps of Russian Federation’s various energy enterprises.

Keywords:
rare earth metals leaching, acid and biological treatment, coal ash, ion exchange concentration, ion exchange resins, scandium, yttrium, lanthanum.
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References

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