Abstract
Since their exceptional rheological behavior, bentonite suspensions are widely used in engineering, industrial, agricultural, and drilling applications. So, the aim of the present study is to investigate the rheological properties of three types aqueous suspensions prepared with calcium bentonite (CaB), sodium bentonite (NaB) obtained from that by Na2CO3 activation, and NaB with the excess soda. The CaB taken from Giresun/Turkey region contains calcium smectite (CaxS) as clay mineral and opal CT (SiO2.nH2O) as impurity which is paracrystalline silica. Soda content by the activation and bentonite content in the suspension were changed in the interval of 2.5-15.0% and 5-20% by mass, respectively. CaxS completely converted to sodium smectite (Na2xS) by the activation with the soda content of 2.5% and then Na2xS+Na2CO3 mixtures formed. Rheological properties of these aqueous suspensions were measured using a Fann Viscometer. These properties reached their maxima by the most thixotropic Na2xS suspensions and greatly increased with the increasing of smectite content. Rheological plots drawn of the shear rate vs. shear stress in the interval of 170-1020 s-1 showed that the suspensions flow as a Bingham Plastic. Change in rheological properties depending on the smectite type and content as well as excess soda content was explained thermodynamically based on the chemical potential gradient between interlayer and dispenser waters.
Highlights
Bentonitic clays are one of the most important industrial raw materials [1]
The effect of opal-CT on the rheological properties of the bentonite suspensions was assumed as insignificant compared to the smectites
Calcium smectite can be converted to sodium smectite by an ion exchange reaction such as soda activation
Summary
Bentonitic clays are one of the most important industrial raw materials [1]. Their clay minerals are smectites such as montmorillonite, nontronite, saponite, beidellite and hectorite. Smectite minerals are hydrous hydroxylated aluminum, iron, and magnesium silicates. Their layered crystal structures are similar but the chemical compositions are different. Smectites layers consist of one octahedral (O) sheet between two tetrahedral (T) sheets which are bonded by oxygen bridges [4]. This three sheets layer is pointed out as T-O-T or 2:1 abbreviation. They have been isolated from bentonite by the purification process [5]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
