|
|
Fixation of the lead in alkali activated materials based on different types of ashes
Cába, Vladislav ; Kalina, Lukáš (referee) ; Koplík, Jan (advisor)
The aim of this work was to develop an alkali activated matrix based mainly on fly ash, to determine the ability to fix lead in these matrices, the impact of added lead on mechanical properties and to reveal the way of lead fixation in these matrices. The matrices consisted mainly of fly ash (four from fluidized bed combustion, one pulverized coal combustion) with an admixture of blast furnace slag and sodium silicate as an activator. Lechates were prepared on the basis of the ČSN EN - 12457-4 standard, lead concentrations in them were measured using an atomic emission spectrometer with inductively coupled plasma. The strengths of the samples were measured after 28 days. Images, element maps and element spectra were taken to determine the structure using a scanning electron microscope with an electron dispersion spectrometer, the samples were analyzed on an infrared spectrometer with a Furier transform, X-ray diffraction analysis and electron spectroscopy for chemical analysis were also used. The individual measurements showed that lead is accumulated in the form of hydroxide. The impact of lead doping on strength of the matrix was different for individual samples. Matrices from both types of fly ash released minimal amounts of lead into leachates, so it is possible to use them to fixate lead.
|
guest ::
RSS feed.