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Wyszukujesz frazę "sepiolite" wg kryterium: Temat


Wyświetlanie 1-2 z 2
Tytuł:
Effect of crystallinity and surface silanol groups on rheological properties of different sepiolites
Autorzy:
Çınar, Mustafa
Gülgönül, Ilhan
Ozdemir, Orhan
Çelik, Mehmet S.
Powiązania:
https://bibliotekanauki.pl/articles/2146875.pdf
Data publikacji:
2022
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
sepiolite
rheology
crystallinity
pH
Opis:
In this study, differences in the rheological properties of three different types of brown sepiolites (K1, K2, and K3) along with one beige (B) sepiolite with different physicochemical properties were explained based on their crystallinity and level of surface silanol groups. Towards this aim, SEM images, XRD and chemical analyses, cation exchange capacity (CEC), and water absorption tests were conducted along with surface area measurements and time-dependent pH profiles. The pH profiles at 3% by wt. revealed that each sepiolite sample attained the equilibrium at different times. These differences showed a parallel behavior with the degree of crystallinity. While sepiolite with better crystallinity (K1) was rather slow in reaching the equilibrium pH, the sepiolites with poor crystallinity (B and K3) reached their equilibrium pH more quickly. The rheological studies conducted with different sepiolites at 3% solids concentration exhibited time-dependent flow of the Bingham plastic model and thixotropic. Differences observed in the rheological behavior of sepiolites were found to correlate with the fiber size, CEC, surface area, and water absorption. The results further indicated that sepiolites with low crystallinity or high level of surface silanol groups (K3 and B sepiolites) show the best rheological properties.
Źródło:
Physicochemical Problems of Mineral Processing; 2022, 58, 5; art. no. 153947
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Rheological behavior of sepiolite suspensions homogenized by ultra-turrax high-speed homogenizer
Autorzy:
Tonkur, Hatice
Can, Muhammed Fatih
Sabah, Eyüp
Powiązania:
https://bibliotekanauki.pl/articles/2146870.pdf
Data publikacji:
2022
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
sepiolite
rheology
modeling
ultra-turrax homogenizer
Opis:
The ability to disperse sepiolite suspensions is of great interest in various fields such as the production of cosmetics, pharmaceuticals, colors, etc., and in preparing the sample material for analytical purposes. In this study, the flow curves and time-dependent rheological behavior of sepiolite aqueous suspensions homogenized by Ultra-Turrax high-speed rotor-stator homogenizer were investigated under operating conditions. Forward and backward flow curves for homogenized sepiolite suspensions at different homogenization times and solid concentrations were plotted, and the amount of existing hysteresis loop was measured to determine the best conditions for the obtention of a suitable product having gel-forming properties for industrial and/or analytical applications. The results showed that the dispersed sepiolite suspensions exhibited a substantial increase in the viscosity values owing to gel formation, and thixotropic behavior that was rapidly improved by the increasing the solid content of suspension/ homogenization time, and their apparent viscosity decreased by the increasing the time of shearing, and flow characteristic was time-dependent. However, changing the distance between dispersing tool/bottom showed no favorable effect on preserving the rheological behavior of sepiolite suspensions, although the apparent viscosity decreased marginally due to increased distance between dispersing tool/bottom. Also, two time-dependent/independent models, namely the Power-law model and the Weltman model, were used to describe the thixotropy behavior, and different parameters of these models were analyzed. The Weltman model was found to be appropriate to fit the timedependency behavior of sepiolite suspensions and the most obtained value for model parameters A and B belonged to sepiolite suspension with 6 wt% at 25 min, which was considered as the optimized sample in the applied experiments, its final viscosity level increased from 0.82 to 12.55 Pas.
Źródło:
Physicochemical Problems of Mineral Processing; 2022, 58, 5; art. no. 153415
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-2 z 2

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