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Problematic of behaviour of APC residues from metallurgical recycling of Pb in soil environment
Vrtišková, Růžena ; Strnad, Ladislav (referee)
Fly ashes from the metallurgical processing of Pb represent the main pollution source of soils in the vicinity of the smelters. The purpose of this thesis was to determine the leaching behaviour of the metallurgical fly ash in simulators of soil solutions - low-molecular-weight (LMW) organic acids. Batch leaching experiment was performed in the time span of 168 hours, at the solid-to-liquid ratio of 1/10 and in 500 µM solutions of organic acids (acetate, oxalate and citrate). In the leachate of acetate and oxalate were measured high concetration of heavy metals as Pb, Cd and Zn. Whereas the leaching efficiency of citrate was lower due to higher pH of suspensions, which is the main factor in this leaching process. According to the calculations using the PHREEQC-2 program the amount of Pb and Cd organic complexes in the leachate are minor (0,1 - 2,1%). Suprasing is the amount of organics complex of Zn and Cu (ZnCitrate- , CuCitrate- ), which is expected to be less mobile due to sorption onto positively charged surface of hydrous ferric oxides and organic matter. As far as acetate and oxalate are concerned, Pb concentrations at the end of experiment are controlled by precipitation of solid Pb acetate and oxalate. This phenomenon can represent a key mechanism of Pb immobilisation in soil systems, in...
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Problematic of behaviour of APC residues from metallurgical recycling of Pb in soil environment
Vrtišková, Růžena ; Strnad, Ladislav (referee)
Fly ashes from the metallurgical processing of Pb represent the main pollution source of soils in the vicinity of the smelters. The purpose of this thesis was to determine the leaching behaviour of the metallurgical fly ash in simulators of soil solutions - low-molecular-weight (LMW) organic acids. Batch leaching experiment was performed in the time span of 168 hours, at the solid-to-liquid ratio of 1/10 and in 500 µM solutions of organic acids (acetate, oxalate and citrate). In the leachate of acetate and oxalate were measured high concetration of heavy metals as Pb, Cd and Zn. Whereas the leaching efficiency of citrate was lower due to higher pH of suspensions, which is the main factor in this leaching process. According to the calculations using the PHREEQC-2 program the amount of Pb and Cd organic complexes in the leachate are minor (0,1 - 2,1%). Suprasing is the amount of organics complex of Zn and Cu (ZnCitrate- , CuCitrate- ), which is expected to be less mobile due to sorption onto positively charged surface of hydrous ferric oxides and organic matter. As far as acetate and oxalate are concerned, Pb concentrations at the end of experiment are controlled by precipitation of solid Pb acetate and oxalate. This phenomenon can represent a key mechanism of Pb immobilisation in soil systems, in...
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