Germanium content in Polish hard coals

Dorota Makowska,Katarzyna Kosowska,Andrzej Strugała,Faustyna Wieroóska

doi:10.1051/e3sconf/20161000121

Abstract

Due to the policy of the European Union, it is necessary to search for new sources of scarce raw materials. One of these materials is germanium, listed as a critical element. This semi-metal is widely used in the electronics industry, for example in the production of semiconductors, fibre optics and solar cells. Coal and fly ash from its combustion and gasification for a long time have been considered as a potential source of many critical elements, particularly germanium. The paper presents the results of germanium content determination in the Polish hard coal. 23 coal samples of various coal ranks were analysed. The samples were collected from 15 mines of the Upper Silesian Coal Basin and from one mine of the Lublin Coal Basin. The determination of germanium content was performed with the use of Atomic Absorption Spectrometry with Electrothermal Atomization (GFAAS). The investigation showed that germanium content in the analysed samples was at least twice lower than the average content of this element in the hard coals analysed so far and was in the range of 0.08 ÷ 1.28 mg/kg. Moreover, the content of Ge in the ashes from the studied coals does not exceed 15 mg/kg, which is lower than the average value of Ge content in the coal ashes. The highest content of this element characterizes coals of the Lublin Coal Basin and young coals type 31 from the Vistula region. The results indicate a low utility of the analysed coal ashes as a source of the recovery of germanium. On the basis of the analyses, the lack of the relationship between the content of the element and the ash content in the tested coals was noted. For coals of the Upper Silesian Coal Basin, the relationship between the content of germanium in the ashes and the depth of the seam was observed.

Highlights

In 2008 the European Commission initiated a discussion on the rare raw materials [1] resulting from China's economic policy
The germanium content in the analysed samples of coal ash is lower than the world average content of germanium for coal fly ashes, which is 18 ± 1 mg/kg [32], while calculating the germanium content in coal samples, the maximum value obtained is 1.28 mg/kg, which is almost twice lower than the world average germanium content in hard coals and even lower than the average content of this element in sedimentary rocks (1.4 mg/kg) or lithosphere (1.7 mg/kg)
Germanium content in the examined Polish coals does not exceed the average content of this element in the earth's crust;

Summary

Introduction

In 2008 the European Commission initiated a discussion on the rare raw materials [1] resulting from China's economic policy. The first report of the working group "Raw Materials Supply Group" of the European Commission "Enterprise and Industry" was announced in 2010 [2], and the in 2014 [3]. These reports set out the situation of raw materials in Europe and a list of elements and minerals necessary for the further development of European countries was compiled. For this reason, it becomes necessary to search for new sources of these metals. A number of studies in the literature discussed the issue of critical raw materials for national mineral resources [4,5] and the current resource market in Poland is monitored by Mineral and Energy Economy Research Institute, Polish Academy of Sciences [6,7]

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