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Wyszukujesz frazę "clay dispersion" wg kryterium: Temat


Wyświetlanie 1-8 z 8
Tytuł:
Clay-organic complexes in a Polish loess soil
Autorzy:
A. Czyż, Ewa
Rejman, Jerzy
R. Dexter, Anthony
Jadczyszyn, Jan
Rafalska-Przysucha, Anna
Stanek-Tarkowska, Jadwiga
Tematy:
carbon sequestration
clay dispersion
complexed organic matter
non-complexed clay
strip tillage
Pokaż więcej
Wydawca:
Polska Akademia Nauk. Instytut Agrofizyki PAN
Powiązania:
https://bibliotekanauki.pl/articles/973053.pdf  Link otwiera się w nowym oknie
Opis:
Complexes formed between clay and soil organic matter are important for carbon sequestration and for soil physical quality. Here, we use samples of loessial soil from South-East Poland to explore the phenomenon of complexing in loess. Soil samples were collected from a single catchment 8 years after the introduction of strip tillage and their compositions were characterized by traditional methods. Complexing was characterized in terms of the content of non-complexed clay which was estimated in two ways: firstly, by measurement of the content of readily-dispersible clay (which was assumed to be the non-complexed clay); and secondly, by calculation using algorithms that had been developed and evaluated previously. The calculations were based on the concept that, at carbon saturation, the clay/organic carbon mass ratio is equal to n. The calculations were done with a range of values of n. It was assumed that the correct value of n was that which gave the greatest coefficient of correlation between the measured values of clay dispersion and the predicted values of non-complexed clay. For the loess used, the optimum value was n = 14.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mechanical dispersion of clay from soil into water: readily-dispersed and spontaneously-dispersed clay
Autorzy:
Czyz, E.A.
Dexter, A.R.
Tematy:
mechanical dispersion
clay
soil
water
readily-dispersed clay spontaneously-dispersed clay
Pokaż więcej
Wydawca:
Polska Akademia Nauk. Instytut Agrofizyki PAN
Powiązania:
https://bibliotekanauki.pl/articles/24323.pdf  Link otwiera się w nowym oknie
Opis:
A method for the experimental determination of the amount of clay dispersed from soil into water is described. The method was evaluated using soil samples from agricultural fields in 18 locations in Poland. Soil particle size distributions, contents of organic matter and exchangeable cations were measured by standard methods. Sub-samples were placed in distilled water and were subjected to four different energy inputs obtained by different numbers of inversions (end-over-end movements). The amounts of clay that dispersed into suspension were measured by light scattering (turbidimetry). An empirical equation was developed that provided an approximate fit to the experimental data for turbidity as a function of number of inversions. It is suggested that extrapolation of the fitted equation to zero inversions enables the amount of spontaneously-dispersed clay to be estimated. This method introduces the possibility of replacing the existing subjective, qualitative method of determining spontaneously-dispersed clay with a quantitative, objective method. Even though the disper-sed clay is measured under saturated conditions, soil samples retaina ‘memory’ of the water contents at which they have been stored.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of controlled dispersion on rheology of swelling clay suspensions in the presence of coal flotation reagents
Autorzy:
Zhang, M.
Cao, Y.
Chen, Y.
Yu, W.
Tematy:
swelling clay
rheological properties
controlled dispersion
flotation reagents
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Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Powiązania:
https://bibliotekanauki.pl/articles/110619.pdf  Link otwiera się w nowym oknie
Opis:
Swelling clay minerals, which are innately capable of dispersing into thin flakes in water, can significantly depress coal flotation. Some researchers partially attribute depression to pulp viscosity increments. This study sought to understand the role of swelling clay minerals in fine coal flotation, by investigating the rheological behavior of bentonite suspensions under controlled and uncontrolled dispersion conditions. The effect of collector, frother, and solution pH on rheological properties of the pulp was studied. Findings showed that at a natural pH, Newtonian flow properties were displayed when bentonite was directly added into a swelling suppressed solution containing calcium ions. The same process was repeated under uncontrolled conditions, and the suspensions transferred from Newtonian to non-Newtonian flows with pseudo-plastic characteristics, depending on the solid density. Further, pH value, methyl isobutyl carbinol (MIBC) and kerosene had the potential to alter the rheological behavior of controlled and uncontrolled systems, especially pH value in the uncontrolled system.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of swelling clay dispersion type on fine coal flotation
Autorzy:
Zhang, Mingqing
Yu, Wei
Cao, Yijun
Xu, Haiyu
Tematy:
fine coal flotation
swelling clay
controlled dispersion
CaCl2
slime coating
Pokaż więcej
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Powiązania:
https://bibliotekanauki.pl/articles/110246.pdf  Link otwiera się w nowym oknie
Opis:
The influence of bentonite dispersion on fine coal flotation was examined to better understand the role of swelling clay in the process of flotation. It was found that the coal flotation recovery was lower with uncontrolled dispersion of bentonite than with controlled dispersion. The detrimental effect was attributed to the increase in slime coating. In the uncontrolled dispersion, the dispersed bentonite platelets formed an extensive card-house structure. The three-dimensional networks increased the slurry viscosity, and caused significant coating of the coal particles, thereby inhibiting particle mobility and bubble-particle attachment. In the controlled dispersion, the bentonite mineral appeared as separate particles with low aspect ratios. The coal particles were partially coated, and the slurry viscosity was lower, resulting in higher flotation recovery. The findings in this study suggested that a practical solution to mitigate the negative impact of swelling clay on flotation would be to maintain high electrolyte levels in the wash water to inhibit clay swelling and dispersion.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Hydration layers on clay mineral surfaces in aqueous solutions: a review
Warstwy uwodnione na powierzchni minerałów ilastych w roztworach wodnych: przegląd
Autorzy:
Min, F.
Peng, C.
Song, S.
Tematy:
warstwy uwodnione
minerały ilaste
dyspersja
siła hydratacji
hydration layers
clay minerals
dispersion
hydration force
Pokaż więcej
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:
https://bibliotekanauki.pl/articles/219390.pdf  Link otwiera się w nowym oknie
Opis:
Hydration layer on clay mineral surfaces is originated from the adsorption of polar water molecules and hydrated cations on the surfaces through unsaturated ionic bonds, hydrogen bonds and van der Waals bonds. It has attracted great attentions because of their important influences on the dispersive stability of the particles in aqueous solutions. This review highlighted the molecular structure of clay minerals, the origin of hydration layers on clay mineral surfaces, the hydration layer structural model, hydration force and the main parameters of affecting the hydration layers on clay minerals (crystal structure, cationic type and strength, and solution pH). Also, the research methods for hydration layers were briefly described, especially the determination of hydration layer thickness by the Einstein viscosity method and AFM method. In addition, the applications of the stability of fine clay mineral particles in aqueous suspensions were summarized.
Warstwa uwodniona na powierzchni minerałów ilastych (gliniastych) powstaje w wyniku adsorpcji polarnych cząsteczek wody i uwodnionych kationów powierzchniowych wiązanych za pomocą nienasyconych wiązań jonowych, wiązań wodorowych i wiązań van der Waalsa. Zagadnienie to wzbudza wiele uwagi ze względu na to, że w dużej mierze warunkuje stabilność dyspersyjną cząstek w roztworach wodnych. W pracy omówiono strukturę molekularną minerałów ilastych, powstawanie warstw uwodnionych na powierzchni minerałów ilastych i siły hydratacji; przedstawiono także model strukturalny warstwy uwodnionej oraz główne parametry warunkujące powstawanie warstwy uwodnionej na powierzchni materiałów ilastych (struktura krystaliczna, rodzaj występujących kationów, stężenie roztworu i jego pH). Ponadto, pokrótce przedstawiono metody badań, ze szczególnym uwzględnieniem badania grubości warstw uwodnionych przy zastosowaniu modelu lepkości Einsteina oraz metody AFM. Ponadto, zestawiono zagadnienia związane ze stabilnością cząstek drobnoziarnistych minerałowa ilastych i ich potencjalne zastosowania.
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-8 z 8

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