The content of heavy metals in foundry dusts as one of the criteria for assessing their economic reuse

The heavy metal content is one of the criteria for foundry dust commercial use. To assess the possibility of foundry dust use, it is necessary to analyze its composition, including the content of basic heavy metals, and its mechanical properties. The paper presents the results of research on foundry dust from one of the Polish foundries. The aim of the study was to assess the waste management based on its composition and content of heavy metals. Dust samples were taken from one of the Polish foundries, producing iron and steel castings. Samples were taken from several places in the foundry, i.e. from electric furnace dust collectors, shock grating unit, transport of moulding sands unit, pneumatic blast cabinet units and the regeneration of spent foundry sand units. Samples were taken twice from each place at the turn of 2017–2018. The total content of heavy metals such as Cd, Pb, Cu, Zn, Cr, Ni, Mn, and Fe for recovery and additionally Hg as environmental pollution was analyzed. Based on the results of the research, it was found that the dust from foundry furnaces and pneumatic cleaners can be used in metallurgy due to a high percentage of iron. It was found that the dust from casting cleaning, transport and regeneration department can be used in the cement or construction industry. In addition, an assessment of the mercury content showed that the re-use of this dust would not cause an environmental hazard. It was found that the profitability of foundry dust use depends on the stability of its composition and requires testing for each batch of dusts.