Browsing by Author "Malinowska, Agnieszka Agata"

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Ograniczenie szkodliwości pyłów stalowniczych poprzez ich zestalanie/stabilizację
(Data obrony: 2008-02-18) Malinowska, Agnieszka Agata
Wydział Odlewnictwa
One of the most important environmental problems in metallurgical processes is how to use dusts produced while preparing the liquid metal. These dusts are often classified as dangerous waste. The paper consists of research findings on leaching of selected heavy metals ( Cr, Cr( VI), Zn, Cu, Fe) out of the dust coming from the dry dust cleanings of furnace arc in one of the foundries. These dusts may contain considerable quantities of harmful metals depending on the scrap used and on the type of smelted steel. Most of these metals tend to leach easily causing real danger for the environment. In case of reduction of heavy metals leaching from steel dusts by solidification / stabilization method using cement. It is not only solidification dusts, but also immobilization of heavy metals by C-S-H phase. The leaching of dusts in raw state as well as solidified with Portland cement has been researched. Cement mixtures had 10 %, 20 %, 40 % and 66 % content of dust. Leavens, training norms and concretes based on cement mixtures with dust were prepared and then technical measures of these were executed. Concrete was also a subject to microscopic research made in order to observe C-S-H phase and how it is influenced by the examined heavy metals. Leaching of heavy metals from so-called TANK METOD concretes was also examined. Average effective diffusion factor for examined heavy metals mobility has been calculated according to Dutch standards concerning leaching. According to those standards a computer program assisting in calculation and simulation of effective diffusion factor has been prepared. The research showed that solidification considerably lowers the leaching of heavy metals in comparison to row dust. This concerns mainly such elements as chrome and lead.