Analysis of the occurrence of critical elements and raw materials in Polish lignite deposits with particular emphasis on coal ashes

Acta Geologica Polonica

“…This was additionally supported by the low mean values of the reflectance coefficient (less than 0.3%) determined on euulminite B (Kwiecińska and Wagner 2001). On the other hand, the investigated lignites were classified as medium-ash (10-20 wt.%), while the ashes produced from the burning of the MPLS-1 represented the calcium-rich type (>10 wt.% of CaO) (Vassilev et al 1997;Wagner et al 2019;. A slight general tendency towards lower δ 13 C of TOC values from the floor to the seam roof may be additional evidence of peat accumulation during the climate cooling (Lücke et al 1999).…”

Gospodarka Surowcami Mineralnymi - Mineral Resources Management

“…In general, bottom ashes, left as residue after the combustion process (e.g., Goldsztejn 2007; Chomiak 2020a), are less frequently investigated than fly ash which is relatively more harmful to the environment (e.g., Galos and Uliasz-Bocheńczyk 2005;Misiak 2015;Wagner et al 2019). The rule is that as the temperature rises, the ash loses organic matter and gains mineral matter (e.g., Kolovos et al 2002;Filippidis et al 1996).…”

“…In general, ash chemistry is of great importance in many aspects of lignite (and hard coal) exploitation, combustion, and ash utilization, including environmental protection (e.g., Filippidis et al 1996;Vassilev et al 1997;Ratajczak et al 1999;Ward 2002;Galos and Uliasz-Bocheńczyk 2005;Carmona and Ward 2008;Markič and Sachsenhofer 2010;Misiak 2015;Karayiğit et al 2019;Oskay et al 2019;Životić et al 2019;and references therein). In Poland, fly ash is analyzed for critical elements content in lignite intended for the production of 'clean energy' (Bielowicz 2016;Wagner et al 2019) and/or its utilization (Galos and Uliasz-Bocheńczyk 2005; Uliasz-Bocheńczyk 2011), while bottom ash obtained in the laboratory is studied for purposes of environmental protection, including human health (Goldsztejn 2007;Bielowicz 2013).…”

“…Simply put, a temperature of 100°C was too low to initiate mineralogical transformations and the incomplete combustion of organic and mineral-organic particles occurred (e.g., Filippidis et al 1996;Markič and Sachsenhofer 2010). Since the CaO content in ashes from lignite burned at different temperatures was relatively high (second only to SiO 2 , Table 1), they can be called Ca-rich ashes (>10 wt%) according to the BN-79/6722-09 standard (e.g., Galos and Uliasz--Bocheńczyk 2005; Wagner et al 2019).…”