Prevention of Trace and Major Element Leaching from Coal Combustion Products by Hydrothermally-Treated Coal Ash

At the present time some 55 million tonnes of Coal Combustion Products (CCPs) are produced each year in Europe (EU 15). These CCPs include combustion residues such as boiler slag, bottom ash and fly ash from different types of boilers as well as desulphurisation products such as spray dry absorption product and FGD gypsum. Out of this total production of 55 million tonnes of CCPs, the amount of coal ash produced is around 47 million tonnes while approximately 8 million tonnes are products obtained from flue gas desulphurisation processes. CCPs are mainly utilised in the building material industry, in civil engineering, in road construction, for construction work in underground coal mining as well as for recultivation and restoration purposes in open cast mining. The majority of CCPs are produced to meet the requirements of standards or other specifications with respect to utilisation in certain areas. The utilisation rate of CCPs differs across European countries depending upon local conditions in respect of issues such as legislation, taxes and climate. The establishment of markets for CCPs has evolved over several decades and has involved a considerable amount of product development and research. As new technologies have been introduced, such as Cleaner Coal Technology (CCT), the power industry has had to adapt by carrying out further development and research to establish both technically and environmentally acceptable utilisation options for CCPs. While much development work has been carried out at a national level, recent years have seen an increasing amount of co-operation between different countries. In Europe an organisation known as ECOBA, the European Association for Coal Combustion, ‥Products has facilitated this.

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Assessment of efficiency of rare earth elements recovery from lignite coal combustion ash via five-stage extraction

Science of Sintering ◽

10.2298/sos2102169m ◽

2021 ◽

Vol 53 (2) ◽

pp. 169-185

Author(s):

Ljiljana Milicic ◽

Anja Terzic ◽

Lato Pezo ◽

Nevenka Mijatovic ◽

Ilija Brceski ◽

...

Keyword(s):

Rare Earth ◽

Rare Earth Elements ◽

Coal Combustion ◽

Extraction Procedure ◽

Coal Ash ◽

Principal Component ◽

Ceramic Materials ◽

Combustion Products ◽

Coal Combustion Products ◽

And Cluster Analysis

Rare earth elements (REE) are frequently referred to as ingredients for enhancements in modern industry, as they are extensively applied in many industrial branches due to their accented electro-magnetic and optical properties. REE have end-utilizations as catalysts, magnets, and as dopants for ceramic materials. Rare earth minerals are scarce therefore the unconventional REE-containing resources such as waste materials and industrial byproducts are continuously being investigated. Coal combustion products comprise REE concentrations varying between 200 ppm and 1500 ppm. This quantity can be isolated though the extraction procedure. In this study, the five stages extraction was conducted on the coal combustion ash from the selected landfill site. The extractions of 32 elements (As, Ga, Ce, Be, Ge, Nd, Cr, Zr, Eu, Cu, Nb, Gd, Co, Mo, Dy, Li, Ag, W, Mn, Cd, Au, Ni, In, Hg, Pb, Sn, Tl, V, Sb, Th, Zn, and La) were conveyed. Chemical analyses were conducted via XRF, ICP-OES, ICP-MS, and AAS techniques. The complexity of the obtained data was examined by Principal component analysis and Cluster analysis in order to derive interconnections between quantity of elements and landfill characteristics, as well as mutual relationships among the elements of interest, and to assess the accomplishment of REE recovery from the coal ash.

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