Characterisation of kaolinite colloidal and flow behaviour via crystallinity measurements

Abstract

Please cite this article as: Bulelwa Ndlovu, Saeed Farrokhpay, Elizaveta Forbes, Dee Bradshaw, Characterisation of kaolinite colloidal and flow behaviour using its crystallinity measurements, Powder Technology (2014Technology ( ), doi: 10.1016Technology ( /j.powtec.2014 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPT A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPT AbstractThis study evaluates the possibility of predicting colloidal and flow behaviour of kaolinite suspensions by measuring kaolinite crystallinity. The Hinckley index of different samples was calculated from XRD spectra as an indicator of the crystallinity. Kaolinite samples with a high Hinckley index showed a defined platy morphology with smooth surfaces of low surface area, while progressively roughened basal planes with prevalent broken edges were observed in kaolinite samples of lower Hinckley indices. Despite similarity in the elemental composition, the kaolinite samples present different surface charge properties, likely due to variations in exposed pH dependent edge sites. Poorly crystallised kaolinite samples were characterised by higher yield stresses and viscosities. This study highlights the importance of crystallinity characterisation towards predicting colloidal behaviour and flow characteristics of kaolinite suspensions.

Kaolen Süspansi̇yonlarinin Susuzlaştirilmasinda Koagülant Ve Flokülantlarin Etki̇si̇

“…IEP value of kaolin was determined as 4.2. This is within the typically reported range for kaolin IEP pH 2.8 to 4.2 [20,21]. The zeta potential of the particles became more negative with the increase of suspension pH and finally decreased to approximately -22.88 mV at a pH 11.…”

Colloidal and Thermal Behaviors of Some Venezuelan Kaolin Pastes for Therapeutic Applications

“…According to Williams and Williams [32], the increase in acidity causes the zeta potential to become less negative and even reach positive values at low pH. The resulting ZP values are noticeably low when compared with other studied kaolins [48][49][50][51]. This behavior could be related to the natural acidity of the studied kaolin aqueous suspensions, to the tendency of these kaolin samples to flocculate, and to the high viscosities measured in the samples.…”

Aplikasi Kaolin dalam Farmasi dan Kosmetik

“…Secara umum, yield stress dan tingkat pengendapan larutan suspensi kaolin menurun dengan meningkatnya pH dan zeta potensial (Gupta et al, 2011). Larutan suspensi yang diformulasikan dengan kaolin kristalinitas rendah menunjukkan tekanan dan viskositas lebih tinggi daripada yang diformulasikan dengan kaolin kristalinitas tinggi (Ndlovu et al, 2015).…”