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    Wyświetlanie 1-7 z 7
    Tytuł:
    Some remarks on attachment of a gas bubble to another phase both immersed in water
    Autorzy:
    Kowalczuk, P. B.
    Drzymala, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/110908.pdf
    Data publikacji:
    2016
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Tematy:
    hydrophobicity
    aquaoleophobicity
    contact angle
    liquid film
    attachment
    Opis:
    In this paper the importance of definition of hydrophobicity and aquaoleophilicity in terms of contact angle as well as the properties of water films in flotation and oil agglomeration were briefly presented. It was shown that the hysteresis of contact angle for a considered system depends on the way of measurement and geometry of the system due to the presence of other that excess pressure and capillary forces and buffering properties of the capillary force. It was suggested that, the measured advancing and receding contact angles should be, when possible, recalculated into the Young (rest, equilibrium) contact angle. It was discussed that quartz is not a good model of hydrophilic surface because its contact angle with a gas phase in water is not zero and that a spontaneous attachment between highly hydrophobic materials such as hydrocarbons and Teflon in dynamic system, such as flotation, does not occur.
    Źródło:
    Physicochemical Problems of Mineral Processing; 2016, 52, 1; 147-154
    1643-1049
    2084-4735
    Pojawia się w:
    Physicochemical Problems of Mineral Processing
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Structure and surface energy of both fluorite halves after cleaving along selected crystallographic planes
    Autorzy:
    Janicki, M. J.
    Drzymala, J.
    Kowalczuk, P. B.
    Powiązania:
    https://bibliotekanauki.pl/articles/110167.pdf
    Data publikacji:
    2016
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Tematy:
    fluorite
    fluoride
    surface energy
    interfacial energy
    cleaving
    reorganization
    surface ions
    Opis:
    The density functional theory, supported with a commercial software, was used to compute the geometry and surface energy of fluorite cleaved along the (111), (110) and (100) planes. In the case of cleaving a piece of fluorite along the (111) plane the two newly created surfaces are identical consisting of fluorite ions with the surface energy equal to 0.384 J/m2. Cleaving fluorite along the (110) plane also provides identical halves and, both contain one Ca ion next to two F ions, with the surface energy equal to 0.723 J/m2. When cleaving takes place along the (100) plane, it creates two corresponding halves with different surface structures. One half, having only surface Ca ions (100Ca) has the surface energy equal to 0.866 J/m2, while the surface energy of the second half, having only F surface ions (100F), is 0.458 J/m2. Different structures and energies of the corresponding fluorite surfaces, that is (100Ca) and (100F) planes, should have an impact on their chemical properties, including hydrophobicity expressed by contact angle. The calculations performed in the paper also showed that reorganization of fluorite surfaces after cleaving was insignificant for all of the investigated planes.
    Źródło:
    Physicochemical Problems of Mineral Processing; 2016, 52, 1; 451-458
    1643-1049
    2084-4735
    Pojawia się w:
    Physicochemical Problems of Mineral Processing
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Influence of frother type and dose on collectorless flotation of copper-bearing shale in a flotation column
    Autorzy:
    Kowalczuk, P. B.
    Mroczko, D.
    Drzymala, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/109396.pdf
    Data publikacji:
    2015
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Tematy:
    flotation
    hydrophobicity
    frother
    shale
    flotation column
    Opis:
    In this paper the influence of nonionic (methyl isobutyl carbinol, tri(ethylene glycol) monobutyl ether) and cationic (hexylamine) frothers on flotation of copper-bearing shale in a flotation column was investigated. It was shown that naturally hydrophobic shale did not float in pure water but it floated in the presence of the investigated frothers. The real contact angle of shale, measured by the sessile drop method, was equal to about 40°, while its effective contact angle was zero when shale was floated in a flotation column in pure water. The investigated surfactants increased the effective hydrophobicity of shale from zero to 16±1, 22±1 and 33±2° for coarse, medium and fine particles, respectively. The calculations of the effective contact angle were based on a simplified probabilistic model of flotation.
    Źródło:
    Physicochemical Problems of Mineral Processing; 2015, 51, 2; 547-558
    1643-1049
    2084-4735
    Pojawia się w:
    Physicochemical Problems of Mineral Processing
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Kinetic separation curves based on process rate considerations
    Autorzy:
    Drzymala, J.
    Ratajczak, T.
    Kowalczuk, P. B.
    Powiązania:
    https://bibliotekanauki.pl/articles/110027.pdf
    Data publikacji:
    2017
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Tematy:
    separation
    flotation
    kinetics
    separation curves
    process rate
    Opis:
    There are many graphical representations of separation results involving time as a crucial parameter determining the kinetics of a process. The graphical representations of results of separation are usually in the form of 2D plots relating two parameters which one of them is time. Time can also be utilized as a complex parameter such as a process rate. The plots involving time are called kinetic curves. Theoretically, the number of kinetic curves is infinite. The basic process kinetic curves, relating either yield (or recovery) and time can be modified to obtain numerous local and global efficiency curves. The global efficiency kinetic curves provide characteristic constants which do not change with the time and yield of a process. In this paper the local and global efficiency plots were created using experimental data which followed the so-called first order kinetics. It was shown that the integral 1st order kinetic equation provided the kinetic constant k which was numerically identical with the 1st order specific rate v, while their units were different (k, 1/min; v, %/(%·min). The global efficiency parameters plotted versus the maximum yield provided another type of plot, which can be called the limits kinetic curve. The limits kinetic curves are very useful for characterizing, quantification and classification of separation systems. The limits kinetic curves can be normalized providing one universal curve with a characteristic point, for instance, v50 indicating the specific rate (or kinetic) constant at the maximum recovery equal to 50%. The mathematical equation of the normalized limits kinetic curve was given in the paper.
    Źródło:
    Physicochemical Problems of Mineral Processing; 2017, 53, 2; 983-995
    1643-1049
    2084-4735
    Pojawia się w:
    Physicochemical Problems of Mineral Processing
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Surface roughness in bubble attachment and flotation of highly hydrophobic solids in presence of frother – experiment and simulations
    Autorzy:
    Kosior, D.
    Kowalczuk, P. B.
    Zawala, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/109319.pdf
    Data publikacji:
    2018
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Tematy:
    surface roughness
    attachment
    flotation
    kinetics
    frother
    Opis:
    In this paper, the kinetic of the three-phase contact (TPC) formation and the flotation recovery of highly hydrophobic solids with different surface roughness were studied in pure water and aqueous solutions of n-octanol. The surface roughness varied between 1 to 100 μm. It was found that there was a strong influence of surface roughness on both kinetics of TPC formation and flotation. The time of three phase contact formation and flotation rate were much faster for rough surfaces in both water and aqueous solutions of frother. Irrespective of the surface roughness, at above a certain frother dose, the attachment time increased and the flotation rate decreased. It was related to the presence of air at the hydrophobic solid surfaces. The mechanism of this prolongation of the time of TPC formation at the solid surfaces with different roughness due to the frother overdosage was discussed, and the experimental data were confirmed by numerical simulations.
    Źródło:
    Physicochemical Problems of Mineral Processing; 2018, 54, 1; 63-72
    1643-1049
    2084-4735
    Pojawia się w:
    Physicochemical Problems of Mineral Processing
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    In search of an efficient frother for pre-flotation of carbonaceous shale from the kupferschiefer stratiform copper ore
    Autorzy:
    Kowalczuk, P. B.
    Buluc, B.
    Sahbaz, O.
    Drzymala, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/109705.pdf
    Data publikacji:
    2014
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Tematy:
    frother
    pre-flotation
    copper ore
    shale
    Opis:
    This papers shows that frothers such as aliphatic alcohols (CnH2n+1OH), poly(propylene glycols) (HO(C3H6O)mH), poly(propylene glycol) alkyl ethers (CnH2n+1O(C3H6O)mH) and poly(ethylene glycol) alkyl ethers (CnH2n+1O(C2H4O)mH), can be used for collectorless flotation of a sample of carbonaceous copper shale manually separated from the Kupferschiefer stratiform copper ore. It was shown that flotation is influenced by the type and dose of frothers. The best flotation results were obtained with tri(propylene glycol) butyl ether C4P3, tri(propylene glycol) propyl ether C3P3 and tri(propylene glycol) P3. For these frothers, the yield vs. frother dose relationship was in the form of convex curves indicating that carbonaceous copper shale can float at relatively low dosages of the frother. It means that these frothers can be used for pre-flotation of carbonaceous matter from the investigated copper ore. Other frothers formed concave yield–frother dose relationships and were less effective.
    Źródło:
    Physicochemical Problems of Mineral Processing; 2014, 50, 2; 835-840
    1643-1049
    2084-4735
    Pojawia się w:
    Physicochemical Problems of Mineral Processing
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Water contact angle on corresponding surfaces of freshly fractured fluorite, calcite and mica
    Autorzy:
    Kowalczuk, P. B.
    Akkaya, C.
    Ergun, M.
    Janicki, M.
    Sahbaz, O.
    Drzymala, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/110595.pdf
    Data publikacji:
    2017
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Tematy:
    contact angle
    surface properties
    cleaving plane
    surface composition
    corresponding halves
    fluorite
    calcite
    mica
    Opis:
    Advancing and receding contact angles of water with corresponding surfaces of freshly fractured calcite, fluorite and mica were measured. The corresponding surfaces were obtained by mechanical splitting of a small lump of each mineral into two pieces. Theoretical considerations revealed that depending on the mineral cleaving plane, surfaces created by splitting into halves can be either identical or entirely different as far as their surface chemical composition is concerned. It was experimentally established that receding and advancing contact angles measured on the corresponding surfaces of fluorite, calcite and mica were identical for the sessile drop method. When the contact angle was measured by the captive bubble approach, there were small differences in the contact angles measured on the corresponding surfaces of fluorite. It was most probably due to surface irregularities and roughness, and therefore different times needed to rupture the liquid film between the bubble and solid surface.
    Źródło:
    Physicochemical Problems of Mineral Processing; 2017, 53, 1; 192-201
    1643-1049
    2084-4735
    Pojawia się w:
    Physicochemical Problems of Mineral Processing
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
      Wyświetlanie 1-7 z 7

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