Split of mercury between products of coal cleaning versus mercury emissions reduction

The article deals with the analysis of the split of mercury present in raw coals between commercial products and wastes in 21 Polish collieries producing hard steam coal (Upper Silesia Coal Basin). The coal cleaning constitutes the first step in the reduction of mercury emissions in coal utilisation (mainly combustion) processes by decreasing the charge of mercury in the commercial products in comparison to the raw coal. The ratio of this reduction depends, first of all, on the technological characteristics of raw coal, as well as on the range of the applied coal cleaning method. The charges of mercury in exploited raw coals are split in coal preparation processes (mainly coal cleaning processes) between commercial products and waste products. The mercury content in commercial products has been analysed together with the emissions from coal combustion processes. In the second case, tools for the reduction of emissions have already been employed. Characteristics of waste products, in particular the mercury content, have been under consideration to a less extent so far. Data presented in the article allows for better, broadened with the waste products, analyses, understanding and assessment of all environmental mercury originated risks, arising from coal production, including coal cleaning. Presented data generate also the need for discussion of such terms like: "mercury reduction in commercial coal products" and "mercury emissions reduction", as the result of coal cleaning processes.