Potentially Economic Concentrations of Rare Earth Elements and Gold in Power Plant Coal Combustion Products (Far East, Russia)

Abstract

The distribution of rare earth elements (REE) and gold (Au) in fly ash released during combustion of brown coal from the Pereyaslavskoye (Siberia) and Erkovetskoye (Far East) deposits has been investigated. Coal combustion was carried out in two locations: the boiler unit of the Blagoveshchenskaya coal-fired power plants (CFPP), equipped with an electrostatic precipitator (ESP); and at the Amur Experimental and Technological Complex (ETC) with the aim of separating the combustion products (slag, fly ash, sludge). It was found that in both processes the highest contents of REE (400 and more ppm) and Au (up to 0.29 ppm) are concentrated in fly ash. These characteristics of coals were used as the basis for the author's calculation of the predicted resources of REE and Au under the conditions of the annual operation of firstly one boiler unit, and then five, equipped with an ESP. Further research by the authors will be aimed at improving the degree of recovery of concentrates through the development of technologies at pilot plants such as ETC “Amur”.

Rare Erath Elements: Their Geological Sources and the Potential of Organosulfonic Acids For Rare Earth Elements Leaching from Coal Ash and Process Optimization

“…These elements occur in clay phases mainly as sorbed forms (by organic matter and clay particles) and fine-grained authigenic minerals (Seredin et al, 1996;Birk & White, 199; associated with coal deposits. Normally, combustion of coal under different conditions results in the concentration of REEs in feed coal ash due to imminent volume changes, Taggart et al, 2016), with concentrations reaching 33 ppm Maity et al, 2022) and 400 ppm (Dugin et al, 2022). However, while coal deposits generally contain lower concentrations of REEs, coal seems containing 300 to 1000 ppm REEs have been reported in some Russian Far East deposits (Seredin et al, 1996).…”