저널

Traditionally and generally used calcined clay was carburized, and its characteristics were studied. Carburization treatment was performed by the thermally decomposed carbon and the deposit carbon which occur in a so called `Boudouard reaction $(2CO{ ightarrow}CO_2+C)`$ at fuel combustion process in a closed-type furnace. The color of the carburized calcine clay changed from yellow to black, and the carbon component revealed as crystalline graphite by the X-ray diffraction test. The weight of the carburized calcine clay decreased to about 4 wt.% by the 1st heating to $1400^{circ}C$ in air but it does not decreased by the 2nd heating of the same conditions. By the carburization treatment, the water absorption changed from 13 wt.% to 6 wt.%, and the contact angle for water drop changed, too, from 0 to $87^{circ}$ which was tested by the photograph of one minute after a water drop contact. It means the carburized calcine clay does not absorb water drop so it has a hydrophobic characteristic.

Calcined clay;Carburization treatment;Crystalline graphite;Thermal analysis;Water absorption;Water contact angle;Hydrophobic;