Influence of mechanical activation on DC conductivity of kaolin

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216208%3A11320%2F18%3A10388650" target="_blank" >RIV/00216208:11320/18:10388650 - isvavai.cz</a>

Alternative codes found

RIV/61389021:_____/18:00498237 RIV/68407700:21110/18:00328175

Result on the web

<a href="https://doi.org/10.1016/j.clay.2017.12.038" target="_blank" >https://doi.org/10.1016/j.clay.2017.12.038</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1016/j.clay.2017.12.038" target="_blank" >10.1016/j.clay.2017.12.038</a>

Result language

angličtina

Original language name

Influence of mechanical activation on DC conductivity of kaolin

Original language description

In this study, the effect of dry milling of kaolin (92 mass% of kaolinite) on its physical properties and microstructure development during firing was investigated using thermal analyses, X-ray diffraction, scanning electron microscopy, and DC conductivity measurements. X-ray diffraction showed a decrease in the intensity of reflections of kaolinite with rising milling time. Moreover, formation of agglomerates from kaolinite particles was observed. A longer milling time led to a lower dehydroxylation temperature and contributed to a more substantial overall contraction of samples. After dehydroxylation, the relative bulk density increased with an increasing milling time. Below the temperature 450 degrees C (start of dehydroxylation), the highest values of the DC conductivity of raw samples were observed for the longest milling times. The main charge carriers are the H+ and OH- ions, originated from dissociation of the adsorbed water and from the coordinated water that was formed during mechanical dehydroxylation of kaolinite, complemented with alkali ions Na+ and K+ which are present as impurities in kaolin. The presence of coordinated water was proven by increasing values of the DC conductivity and by decreasing values of conduction activation energy from 1.73 eV to 0.85 eV with increasing milling time. A similar trend of conduction activation energy was observed in the temperature range 650-750 degrees C, where the values of conduction activation energy changed from 0.79 eV to 0.52 eV with increasing milling time. After dehydroxylation (above 750 degrees C), the DC conductivity of raw samples slightly decreased with increasing milling time.

Czech name

—

Czech description

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Type

J_imp - Article in a specialist periodical, which is included in the Web of Science database

CEP classification

—

OECD FORD branch

10302 - Condensed matter physics (including formerly solid state physics, supercond.)

Project

<a href="/en/project/GBP105%2F12%2FG059" target="_blank" >GBP105/12/G059: Cumulative time dependent processes in building materials and structures</a><br>

Continuities

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Publication year

2018

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Name of the periodical

Applied Clay Science

ISSN

0169-1317

e-ISSN

—

Volume of the periodical

154

Issue of the periodical within the volume

154

Country of publishing house

NL - THE KINGDOM OF THE NETHERLANDS

Number of pages

7

Pages from-to

36-42

UT code for WoS article

000424722900005

EID of the result in the Scopus database

2-s2.0-85039718270