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Experimental in situ transformation of smelting wastes in soil systems
Jarošíková, Alice ; Ettler, Vojtěch (advisor) ; Hiller, Edgar (referee) ; Doušová, Barbora (referee)
Metallurgical activities are one of the important sources of environmental pollution, especially due to inappropriate treatment of waste materials containing potentially harmful elements. Soils in the vicinity of smelting operations are the main target reservoirs for these emitted contaminants. The aim of this study was to depict reactivity of copper smelter flue dusts and slags in aqueous and soil environments using laboratory and field experiments. Slags exhibited high concentrations of As (up to 0.95 wt.%), Cu (up to 2.4 wt.%), Pb (up to 1.02 wt.%), Sb (up to 0.37 wt.%), and Zn (up to 2.45 wt.%). Copper and other metal(loid)s were predominantly bound in sulphides, especially bornite, digenite, chalcocite, and galena. Flue dusts were mainly composed of As2O3 phase (arsenolite and claudetite), with minor amounts of gypsum, galena, quartz and covellite. The main contaminants in the dust were As (53.3 wt.%), Pb (3.41 wt.%), Sb (1.26 wt.%), Zn (1.41 wt.%), Cu (1.07 wt.%) and Bi (0.80 hm.%). The leaching tests performed in the pH range of 3-12 indicated that the release of metal(loid)s from both types of metallurgical wastes was highly pH-dependent. During the leaching in deionised water, up to 42 mg/kg As was released from slags and up to 52.6 g/kg was leached from the flue dust; the latter highly...
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Mineralogy of particulates from semi-arid soils polluted by mining and smelting and their transformation/re-mobilization during bushfires
Tuhý, Marek ; Ettler, Vojtěch (advisor) ; Kříbek, Bohdan (referee)
This thesis is focused on biomass-containing topsoils from a highly contaminated semi-arid area in the vicinity of mining and smelting operations in Tsumeb and Kombat in the northern Namibia. The highest concentrations of inorganic contaminants were found in samples from Tsumeb and attained the following values (mg/kg): As 1920, Cd 81, Cu 5840, Hg 7,66, Pb 4880, Sb 266, Zn 3310. X-ray diffraction analysis (XRD), scanning electron microscopy (SEM) and electron microprobe analysis (EPMA) have been used for determination of mineralogical composition of particulates adhering to surfaces of biomass and occurring in the heavy mineral fraction of topsoils. Quantitative partitioning of contaminants within individual mineral phases has been determined using autoSEM; contaminants were mainly bound in the slag glass (As: 16.7 %; Cu: 12.7 %; Pb: 26.2 %; Zn: 33.9 % of total concentration) and in metal(loid)-rich Fe-hydroxides (As: 14.4 %; Cu: 7.7 %; Pb: 21.6 %; Zn: 32.5 %). On biomass- rich topsoil samples, we have experimentally proved that bushfires can be responsible for transformation and re-mobilization of contaminants. Mercury is completely released at temperatures around 300 řC. In the same temperature range, also As anad Sb are released due to arsenolite (As2O3) thermal degradation. Cadmium is released...
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Leaching from slags and fly ashes from nickel metalurgy (Niquelandia and Barro Alto, Brasil)
Kvapil, Jindřich ; Ettler, Vojtěch (advisor) ; Vítková, Martina (referee)
Slag and fly ash originating from processing lateritic Ni-ore in the districts of Niquelândia and Barro Alto in Brazil are enriched with potentially toxic elements (PTEs). Higher contents of Ni and Co were observed in case of the fly ash (25 g/kg and 462 mg/kg, respectively), whereas higher concentration of Cr was observed in the slag (7, 58 g/kg). Mineralogical investigations indicate that slag mainly consists of olivine, pyroxene and glassy matrix. High content of glass corresponds to the product of quenching of slag melt in water basins during granulation. In contrast, the fly ash was mineralogically more complex with olivine, pyroxene, glassy phase and partly dehydrated serpentine phase, spinel, SiO2 and the furnace feed residues. Contaminant leaching was highly pH-dependent with the highest releases of PTEs from the fly ash at pH 3: up to 5, 42 g/kg Ni, 112 mg/kg Co and 4, 3 mg/kg Zn. Slag was significantly more stabile; only 47,9 mg/kg Ni was released at pH 3, but compared to the fly ash higher release of Cr was reported (up to 25.6 mg/kg). Towards alkaline conditions, the leachability of PTEs significantly decreases. Based on physic-chemical parameters of leachates, theoretical speciation of elements and saturation indices for selected solubility-controlling phases were calculated by...
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