CMV - laboratoř anorganických materiálů

Browse

Recent Submissions

Now showing 1 - 5 of 35
  • Thumbnail Image
    Item
    Application of fly ashes from fluid bed coal combustion within refractory materials
    (IOP Publishing, 2018-07-12) Kotrla, Jan; Šoukal, František; Másilko, Jiří; Švec, Jiří; Janča, Martin
    The study deals with the possibility of utilization of fly ashes from coal combustion in refractory materials and its influence on resulting properties of the material. The effect of bed and filter ash addition on the properties of the droplet and the resulting mechanical properties, bulk density, shrinkage and firing temperature of stove fireclay. The subject of this study is also reduction of SO2 emissions evolved burning of fireclay containing fluid ash rich of anhydrite. Emissions of SO2 were observed by TG-DTA method. Characterization of prepared samples and study of heat treatment processes were based on XRD and TG-DTA.
  • Thumbnail Image
    Item
    Effect of Na3PO4 on the Hydration Process of Alkali-Activated Blast Furnace Slag
    (MDPI, 2016-05-20) Kalina, Lukáš; Bílek, Vlastimil; Novotný, Radoslav; Mončeková, Miroslava; Másilko, Jiří; Koplík, Jan
    In recent years, the utilization of different non-traditional cements and composites has been increasing. Alkali-activated cementitious materials, especially those based on the alkali activation of blast furnace slag, have considerable potential for utilization in the building industry. However, alkali-slag cements exhibit very rapid setting times, which are too short in some circumstances, and these materials cannot be used for some applications. Therefore, it is necessary to find a suitable retarding admixture. It was shown that the sodium phosphate additive has a strong effect on the heat evolution during alkali activation and effectively retards the hydration reaction of alkali-activated blast furnace slag. The aim of the work is the suggestion of a reaction mechanism of retardation mainly based on Raman and Xray photoelectron spectroscopy.
  • Thumbnail Image
    Item
    Effect of Ultrasonication Dispersion Technique on Sintering Properties of CNT Reinforced Al-Zn-Mg-Cu Powder
    (Polish Academy of Sciences, 2017-01-01) Rudianto, Haris; Dlouhý, Ivo; Šoukal, František
    CNT has been researched significantly due to its properties especially mechanical and conductivity properties. Due to strong affinity between particles, dispersion has been remained a problem for its applications. Ultrasonication technique was used to disperse CNT on aluminum powder. Ultrasonication has successfully dispersed CNT on aluminum powder in ethanol. Low energy ball milling for 1h under argon gas with 5: 1 ball to powder ratio was used to optimize dispersion of CNT on aluminum. CNT concentration in this research is ranged from 0.1 up to 3wt%. Premix Al-5.5Zn-2.5Mg-0.5Cu powder was used as matrix for this research. Sintering at 580 degrees C for 1h under argon gas was carried to produce high density materials. Pores are still remained on material and it is possibility that pores were caused by agglomeration of CNT. Dispersion high content of CNT is still remained obstacle on this research. Aluminum carbide, Al4C3 is recognized as a ` bridge between aluminum and CNT for stress transfer was investigated in this research. Raman Spectroscopy, XRD and SEM-EDS were carried out to characterize materials.
  • Thumbnail Image
    Item
    Reactivity of meta-talc in sodium hydroxide medium
    (IOP Publishing, 2018-07-12) Bednárek, Jan; Ptáček, Petr; Šoukal, František; Havlica, Jaromír; Novotný, Radoslav; Másilko, Jiří; Šiler, Pavel
    This work deals with the reactivity of XRD amorphous delaminated and dehydroxylated talc phase (meta-talc), in alkali medium. Talc ore Luzenac H70 was treated in a stirred ball mill (attritor) for 30; 60 and 90 min with subsequent thermal treatment at 700°C; 750°C and 800°C. Reactivity of mechanochemically and thermally treated talc ore in NaOH solution was studied using isothermal calorimetry. An influence of material crystallinity and amount of water coordinated in material structure after milling on its reactivity in alkali medium was studied.
  • Thumbnail Image
    Item
    Release of ammonia from conventional power plant fly ash after the introduction of SNCR process
    (IOP Publishing, 2018-07-12) Beranová, Denisa; Opravil, Tomáš; Ptáček, Petr; Snop, Roman
    The paper deals with a study of various factors affecting the release of ammonia from conventional power plant fly ash after introduction of SNCR (Selective non-catalytic reduction). SNCR is a method of flue gas denitrification based on the chemical reduction of nitrogen oxide into nitrogen and water vapour. Reduction has many by-products, various ammonia salts, which could contaminate fly ash and deteriorate its properties and application. The chemical and phase composition of fly ash was determined by X-Ray Fluorescence and X-Ray Diffraction. To predict the contaminated fly ash behaviour, the samples of fly ash with known ammonia content was prepared by mixing fly ash with exact amount of ammonia hydrogensulfate. Tests were performed on the samples prepared from contaminated fly ash as it was, contaminated fly ash with deionized water and as a mixture of contaminated fly ash, lime, gypsum and water (further stabilizate). Effects of various storage and mixing conditions on prepared samples properties were studied.