Mineralogical and chemical characterization of DD3 kaolin from the east of Algeria

Hamza Senoussi a, Hocine Osmani a, Christian Courtois b, Mohamed el Hadi Bourahli a,∗
a Non Metallic Materials Laboratory, Institute of Optics and Precision Mechanics, University Ferhat Abbes, Setif 1 Algeria
b Ceramics Materials and Processes Laboratory, University of Valenciennes and Hainaut-Cambresis, France

The mineralogical and chemical characteristics, based on X-ray diffraction (XRD) and scanning
electron microscopy, of a kaolin known as DD3, from eastern Algeria were examined
in the present study.
The results showed that kaolin DD3 has an alumina content of 39%. The SiO2/Al2O3 molar
ratio of 2.14 is close to that of a pure halloysite. The hematite concentration is relatively
large and the flux oxides ratios remain as acceptable impurities. Microscopic observations
showed a predominant tubular halloysite phase, flattened hexagonal platelets corresponding
to the presence of kaolinite and its polymorphs (nacrite, dickite), and hydrated alumina.
The SiO2/Al2O3 molar ratio and tubular DD3 suggest possible uses in technical ceramics and
nanotechnology applications.
Analysis by XRD revealed the presence of many phases. Thermal treatment at 450 ◦C and
chemical treatment with HCl confirmed the presence of halloysite. The inclusion in the clay
of organic molecules (dimethylsulfoxide (DMSO), DMF, and diluted glycerol) showed that the
DMSO led to expansion of the inter-planar distance. The intercalation by DMSO molecules
resulted in a shift of the basal peak from 10 to 11.02 A˚ and partial displacement of the peak
from 3.35 to 3.65 A. ˚ These two peaks are characteristic of halloysite. The presence of residual
nacrite was also confirmed by the shift of the peak observed at 3.35 A. ˚
A full analysis of the XRD patterns using the Match software, based on these results,
showed that the DD3 clay consists of >60% halloysite.

Original Article at: https://ac.els-cdn.com/S0366317515001260/1-s2.0-S0366317515001260-main.pdf?_tid=26e52889-5066-480f-b857-c000bb1d6d3c&acdnat=1523718766_594018c22dd1ec83f91c55473e1eab0b

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