R. L. Davison, D. F. S. Natusch, J. R. Wallace and C. Evans Jr, “Trace Elements in Fly Ash. Dependence of Concentration on Particle Size,” Environmental Science & Technology., Vol. 8, No. 13, 1974, pp. 1107-1113. doi:10.1021/es60098a003

has been cited by the following article:

• TITLE: Dissolution of Rare Earth Elements from Coal Fly Ash Particles in a Dilute H2SO4 Solvent

  AUTHORS: Shunsuke Kashiwakura, Yuichi Kumagai, Hiroshi Kubo, Kazuaki Wagatsuma

  KEYWORDS: Coal Fly Ash; Rare Earth Elements; Dissolution Behavior; Unreacted Core Model

  JOURNAL NAME: Open Journal of Physical Chemistry, Vol.3 No.2, May 23, 2013

  ABSTRACT: Recently, the worldwide supply of rare earth element (REE) resources will be severely restricted. On the other hand, coal fly ash particles emitted from coal-fired electric power plants contain relatively high concentrations of REEs. The contents of REEs in coal fly ash are regularly several hundreds of ppmw. In order to extract and recover REEs from coal fly ash particles, as a first step, we have investigated their dissolution behavior in a dilute H2SO4 solvent. The REE content of coal fly ash specimens has been precisely determined, and their presence in the ash component of the original coal and their enrichment in coal fly ash particles during coal combustion have been suggested. REEs in coal fly ash dissolve gradually in H2SO4 over time, and this implies two types of occurrences of the REEs in coal fly ash particles. By applying the unreacted core model to the dissolution behavior of REEs in a H2SO4 solvent, we can explain both types of occurrences.