Deflocculant consumption of clay suspensions as a function of specific surface area and cation exchange capacity

Clay Minerals ◽  
2013 ◽  
Vol 48 (3) ◽  
pp. 473-480
Author(s):  
D. G. G. Delavi ◽  
A. De Noni ◽  
D. Hotza

AbstractCeramic tile production by the wet route requires clay suspensions with a high solid content and low viscosity. In this work the deflocculation of clays in aqueous suspensions was investigated by varying the type of clay and additive. Three kaolinitic and two illitic clays were characterized and dispersed with deflocculants based on lithium, sodium and potassium silicates and polyacrylates. The clays were characterized by chemical and mineralogical analyses, particle size distribution, zeta potential, organic carbon content, cation exchange capacity (CEC) and specific surface area (BET). Deflocculation curves were determined by measuring the viscosity for 50 wt.% clay slips. The results indicate that additive consumption is closely related to CEC and BET, which correspond respectively to the chemical and physical characteristics of the clay mineral's surface. Moreover, viscosity values at the deflocculation point are closely related to BET.


Clay Minerals ◽  
2019 ◽  
Vol 54 (4) ◽  
pp. 369-377 ◽  
Author(s):  
Maja Milošević ◽  
Predrag Dabić ◽  
Sabina Kovač ◽  
Lazar Kaluđerović ◽  
Mihovil Logar

AbstractThis study focuses on the mineralogical characterization of four raw clay samples from Dobrodo deposit, Serbia. Several analytical methods were applied to determine the chemical and mineralogical composition, morphology and physical properties (colour, plasticity, specific surface area, particle size and cation-exchange capacity) of the clay samples. Kaolinite, smectite and illite are the predominant phases in all of the samples studied that contain between 60.2 and 87.1 wt.% of clay. Quartz, feldspars, paragonite and Ti- and Fe-bearing phases were also identified. The relatively high SiO2/Al2O3 mass ratio indicates abundant quartz. The cation-exchange capacity of the samples varied between low and moderately charged clay minerals (12–52 mmol 100 g–1) with specific surface area values ranging from 94 to 410 m2 g–1. The plasticity index values (11–23%) suggest low to moderate plasticity. Preliminary results show that most of the raw clay from Dobrodo deposit might be suitable for use in ceramic applications.



Geoderma ◽  
2006 ◽  
Vol 135 ◽  
pp. 216-223 ◽  
Author(s):  
E.N. Hepper ◽  
D.E. Buschiazzo ◽  
G.G. Hevia ◽  
A. Urioste ◽  
L. Antón


2016 ◽  
Vol 30 (3) ◽  
pp. 369-374 ◽  
Author(s):  
Kamil Skic ◽  
Patrycja Boguta ◽  
Zofia Sokołowska

Abstract Parameters of specific surface area as well as surface charge were used to determine and compare sorption properties of soils with different physicochemical characteristics. The gravimetric method was used to obtain water vapour isotherms and then specific surface areas, whereas surface charge was estimated from potentiometric titration curves. The specific surface area varied from 12.55 to 132.69 m2 g−1 for Haplic Cambisol and Mollic Gleysol soil, respectively, and generally decreased with pH (R=0.835; α = 0.05) and when bulk density (R=−0.736; α = 0.05) as well as ash content (R=−0.751; α = 0.05) increased. In the case of surface charge, the values ranged from 63.00 to 844.67 μmol g−1 Haplic Fluvisol and Mollic Gleysol, respecively. Organic matter gave significant contributions to the specific surface area and cation exchange capacity due to the large surface area and numerous surface functional groups, containing adsorption sites for water vapour molecules and for ions. The values of cation exchange capacity and specific surface area correlated linearly at the level of R=0.985; α = 0.05.



Author(s):  
Atma Sharma ◽  
Budhaditya Hazra ◽  
Giovanni Spagnoli ◽  
Sreedeep Sekharan

Specific surface area (SSA) and cation exchange capacity (CEC) are two fundamental clay properties. However, the determination of CEC and SSA is challenging due to inherent uncertainties and difficulty in experimental measurement. Popular approach is to employ transformation models for its estimation. However, most of the existing models were developed on limited sample sizes, and quantification of uncertainty associated with the estimate is not possible. Therefore this study proposes a multivariate probabilistic approach for estimation of CEC and SSA. First, a five-dimensional database (278×5) for parameters liquid limit (LL), plasticity index (PI), clay fraction (CF), CEC and SSA (labelled as CLAY/C-S/5/278) is developed. Thereafter, multivariate distribution for the five parameters in the database is constructed using vine copula approach. Implementation of the proposed approach is demonstrated by updating prior/unconditional probability density function (PDFs) of CEC and SSA given single/ multiple clay parameters using Bayes’ rule. The posterior/conditional PDFs of CEC and SSA are also summarized as practitioner friendly analytical expressions. Two geotechnical application examples are also shown. In the proposed approach, CEC and SSA are characterized by their complete joint distribution, and is, therefore, superior to the popular deterministic transformation approach in literature.



Soil Science ◽  
1989 ◽  
Vol 148 (4) ◽  
pp. 250-257 ◽  
Author(s):  
MICHAEL L. THOMPSON ◽  
HAILIN ZHANG ◽  
MASOUD KAZEMI ◽  
JONATHAN A. SANDOR


2016 ◽  
Vol 7 (01) ◽  
pp. 137-140
Author(s):  
Sri Hilma Siregar ◽  
Wirdati Irma

Bentonite is a material that has several layers, which consists of one layer of octahedral and two tetrahedral layers or commonly known as the bentonite mineral that is composed of layers of 2: 1. Bentonite nature in general is less than optimal when used as an adsorbent. This can be overcome by activating the natural bentonite either chemistry or physics. In this study, natural bentonite acid activated. Bentonite activated with HF acid with a variety of 1% -5%. Acid can damage the structure of octahedral layers in the space between the layers. Effect of activation with HF acid cause ion exchange of Al3+, Fe3+, Mg2+ with H+ ions from the acid HF so changes smectite crystalline structures. Activation of bentonite with lead acid cation exchange capacity decreased and significantly increases the specific surface area of 26.893 m2 / g (natural bentonite) to 43.167 m2 / g (activated).





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