Stimulation of Leaching of Rare Earth Elements from Ash and Slag by Energy Impacts
V. A. Chanturia, V. G. Minenko, A. L. Samusev, E. V. Koporulina, C. A. Kozhevnikov
Academician Melnikov Research Institute of Comprehensive Exploitation of Mineral Resources-IPKON, Russian Academy of Sciences, Moscow, Russia
Keywords: Ash and slag, rare earth elements, leaching, efficient parameters, kinetics, energy impacts
Abstract
The authors describe the studies into nitrate leaching of rare earth elements (REE) from ash and slag. The morphology, texture and structure of surface of ash and slag micro spheres are examined using the methods of scanning electron microscopy and X-ray phase analysis. The experimental efficient parameters of nitric leaching of REE, which ensure the maximum REE extraction at the level of 50.4% include: the temperature of 130 °С, the nitric acid concentration of 7.2 M, the leaching duration of 180 min and the mineral suspension stirring frequency of 500 min-1. The REE leaching kinetics conforms with the pore-diffusion model of nucleus shrinkage. It is possible to stimulate REE leaching by preliminary treatment of ash and slag by powerful electromagnetic impulses and ultrasound, which ensures intense disintegration of aluminosilicate micro spheres and, as a consequence, provides increased extraction of REE in subsequent leaching by 1.8-18.2%.
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