Corrigendum to “Metallurgical slags from Cu production and Pb recovery in Poland - Their environmental stability and resource potential” [Appl.
Geochem. 98 (2018) 459-472].
Copper is recovered from ores mainly by means of pyrometallurgical processes that are responsible for generating waste slag, estimated at a level of ca. 2.2 tons of slag for every ton of Cu (Gorai et al., 2003; Jarošíková et al., 2017). Worldwide production of recoverable Cu reached 19.7 Mt in 2017 (USGS, 2018), and was associated with at ca 43 Mt of slags in 2017.
Copper slags resemble basalt
Rocks from chemical and mineralogical point of view. Their chemical nature and other unique properties (sharp-edged shape, resistance to corrosion) enable utilization of slags in many ways, for example in road construction (Murari et al., 2015 and references therein) or as replacement of sand in concrete of different applications (Shi et al., 2008;Wu et al., 2010; Kua, 2013). On the other hand, these materials contain substantial amounts of potentially toxic elements. These include, Cu, Pb, Zn, As, Cd, Cr etc., which are proved to pose danger to biotic and abiotic environments (Kabata-Pendias and Szteke, 2015; Potysz et al., 2016a, 2017, 2018c). These elements can be released from the slags as the result of prolonged exposure to weathering conditions and consequently contaminate nearby ecosystems as proven in numerous studies (Piatak et al., 2004, 2015; Lottermoser, 2005; Vítková et al., 2010,
2011; Kierczak and Pietranik, 2011; Kierczak et al., 2013; Khorasanipour and Esmaeilzadeh, 2016; Kaksonen et al., 2017; Potysz et al., 2018b).
Mineralogical and chemical investigations are useful not only to understand the environmental impacts of slag dumps, but also to reproduce slag formation conditions (Sāez et al., 2003; Puziewicz et al., 2007; Ettler et al., 2009; Warchulski et al., 2015; Potysz et al., 2016b; Tyszka et al., 2018).
Copper is recovered from Kupferschiefer ores located in SW Poland. In 2015, 479,000 Mg of Cu was produced (Kozłowska-Roman and Oszczepalski, 2016), which was associated with the generation of over 1 Mt of slag. Polish copper deposits contain considerable amounts of metals that are not recovered in the smelting process, e.g. REE, Co, Mo and V (Kucha, 2003; Sawłowicz, 2013; Oszczepalski et al., 2016; Sawłowicz and Sutton, 2017). These metals (except for Mo) are listed as critical raw materials for the EU (EC, 2017) because they are not produced from the EU resources, their availability is limited and the
demand is covered by import, mostly from unstable countries, which
provides high supply risk.
In this study, the authors examined three different slag residues derived from Cu production in SW Poland. Leaching protocols applied to assess the environmental stability of examined materials revealed that simulated rainfall leads to negligible metal(loid) discharge in the view of the worst-case scenario. On the other hand, sequential extraction results indicate that the metals are not bound to labile fractions unless the material is highly amorphous (GS). Nonetheless, the results of this study demonstrated that studied slags are susceptible to release out metals. Therefore, further focus of this research should be placed on metal recovery feasibility studies. The high concentrations of valuable metals considered critical or scarce (REE, Co, Mo, V) in slags combined with their dubious environmental stability can be seen as an imperative to conduct further research concerning the efficient recovery of metals
from these slags. The recovery can be achieved using environmentfriendly methods, e.g. bioleaching, which is currently being performed by our team.
Since sulfuric acid has been one of the most frequently studied extracting agent proven to perform efficient extraction, an application of H2SO4 will be done. Furthermore, H2SO4 can also be biologically produced (Oliveira et al., 2013). Thus, biologically assisted metals extraction is a “green” alternative to the chemical leaching. On the other hand, organic extractants are also known for their good performance due to complexing features. Thus, a comparison between inorganic and organic leaching, as well as chemical versus biological leaching, will be attempted as the next steps of the authors' studies.
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