Selected Critical Raw Materials in Waste from Coal Gasification in Poland

Barbara Bielowicz

doi:10.3390/en14238071

Abstract

In an effort to identify new sources of critical raw materials (CRMs) possibility of recovering selected CRMs from Polish coals, chars, and ashes resulting from the combustion of coals and chars was investigated. The samples were collected from pilot fluidized bed gasification systems. The search for CRMs in coal gasification wastes has not been widely reported before. The study used 2 bituminous coal and 1 lignite sample; the concentration of individual critical raw materials (CRMs) was analyzed using the ICP-MS method. The obtained results were compared with Clarke values in coal ash and in the Earth’s crust, and with the adopted cut-off grade. As shown by the analysis, the highest concentrations of CRMs can be found in fly ash, mainly in samples from the eastern part of the Upper Silesian Coal Basin. This applies mostly to Be, Cs, or Sb due to the fact that their concentrations were found to be higher than the Clarke value in the Earth’s crust; the mentioned fly ashes could be used as potential sources of critical elements if appropriate recovery technologies are developed. In addition, the tested materials have elevated Se, Pb, Ni concentrations, but their recovery is currently not economically viable. Compared to the currently adopted cut-off grade levels, there are no critical elements in the analyzed coal gasification waste that could be recovered.

Highlights

Because of the ever-increasing environmental degradation associated with the exploitation and use of non-renewable energy resources, work is being done on the development of environmentally friendly technologies for obtaining energy from coal
Of the 56 elements analyzed, the critical raw materials whose concentrations in the analyzed samples were above the minimum detection limit were selected (Supplementary Materials)
The detailed description of the critical raw materials for which no Clarke value has been calculated, even though they are present in large amounts in coal and its ashes, is omitted

Summary

Introduction

Because of the ever-increasing environmental degradation associated with the exploitation and use of non-renewable energy resources, work is being done on the development of environmentally friendly technologies for obtaining energy from coal. One of these technologies is the gasification of coal. The gasification process includes surface gasification following the exploitation of coal and underground gasification; the process is carried out directly in the seam The latter is not widely used due to a number of requirements related to geological, environmental, and hydrogeological conditions of underground coal gasification [2]. The current energy policy of Poland. [4] and the world is aimed at the implementation of circular economy, i.e., the best possible use of the waste generated

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Results

Conclusion