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Geopolymers: The influence of alkaline activator cations on efflorescence
Novotná, Martina ; Polonská, A. ; Šídlová, M. ; Perná, Ivana
This paper describes the effect of the type of cations in the alkaline activator on geopolymer properties and especially on the formation of efflorescence. The susceptibility to the formation of efflorescence is discussed according to the standard ČSN 72 1565-13. Cations in alkaline activators influence the mineralogical type of efflorescence: Li+ and Na+ cations form carbonates (Li2CO3 and Na2CO3, respectively), whereas K+ cations form sulphate (K2SO4). The mechanical properties, workability and pore structure of the geopolymer composites have been determined. Alkaline activators with sodium and potassium ions reach higher mechanical strength than those containing lithium cations. For lithium alkaline activators, there was a noticeable difference in the properties between the SiO2/Li2O ratios 1.8 and 2.6. Based on the properties of the mentioned geopolymer composites with various alkaline cations, it is possible to use lithium alkaline activators in geopolymer technology.
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Chemical Properties of Flue Gas Desulphurization Gypsums from Different Energy Sources
Kroulíková, S. ; Mercl, F. ; Száková, J. ; Perná, Ivana ; Tlustoš, P.
There were compared flue gas desulphurization gypsums (FGDGs) from four different power plants in the Czech Republic on chemical properties (pH, total content of nutrients and risk elements) and then was assessed their potential for utilization in agriculture as fertilizer without any risk to the environment. According to our results, the FGDGs represent an important possible source of sulphur (17.8 – 19.0 %) and calcium (23.0 – 30.2 %) for reduction of their deficit in the soil. However, contents of arsenic and of mercury in three of the tested FGDGs not fulfil the limit values for fertilizers. In the future, the remaining FGDG is thus necessary to evaluate for its fertilizing effects in model and field conditions.\n\n
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Rehabilitation of slag
Hanzlíček, T. ; Perná, Ivana ; Šupová, Monika
The paper describes the historical context of the heap of blast furnace slag in Kladno. It also characterizes the chemical and mineralogical composition and offers an explanation of the different composition of the bottom active and top inactive layers. It was found that if the slag contains active components in the form of a disordered gehlenites it can be easily reprocessed by alkaline activation into valuable, stable and water-insoluble matter.
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The ash quality monitoring of biomass combustion
Tlustoš, P. ; Ochecová, P. ; Száková, J. ; Perná, Ivana ; Hanzlíček, Tomáš ; Habart, J. ; Straka, Pavel
The aim of methodology was, on the basis of results of analyzes of ash from more than 40 sources in the Czech Republic, these ash categorize by feedstock and identify suitable ash for use on agricultural land. It could lead to a significant shift to reduce the cost of incinerators, to the entry of new businesses on the market and to easier fulfilling of republican obligations in the share of energy production from renewable sources. Another advantage of finding employment for these materials, from an environmental view, is the reduction of landfilling and support for recycling of nutrients. The methodology presented the process for the selection of suitable ash for agricultural purposes and the reader should be able to determine the applicability of the material.
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Research and development of the new materials and technology for treatment of radioactive and danger waste
Vokál, A. ; Hanzlíček, Tomáš ; Kiselová, M. ; Laciok, A. ; Landa, J. ; Lukin, D. ; Perná, Ivana ; Polívka, P. ; Sázavský, P. ; Selucký, P. ; Steinerová, Michaela ; Straka, Pavel ; Vojtěchová, H.
Development of geopolymer composites for storing of hazardous radioactive sledge and spent ion exchangers from Czech nuclear power stations.
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