ISSN 1017-2548(Print)
ISSN 2234-8530(Online)
Volume 16, Number 4
JKCSEZ 16(4)
August 20, 1972 

Hadong-Kaolin was treated with aqueous sodium hydroxide solution. The crystalline structure was studied by X-ray powder diffraction method. The optimum conditions for various crystal formation were as follows: Crystal Concentration Temp. reating time Halloysite 1~4 N NaOH 60℃ 0.5~4 hr Sodium A zeolite 0.5~2 N NaOH 80~100℃ 6~20 hr Hydoxysodalite > 4 N NaOH 80~100℃ > 4 hr The ratio of Na2O to SiO2 for crystallizing sodium A zeolite was 0.5-1.5. The Ca++ ion exchange capacity of produced sodium A zeolite for 0.2 N CaCl2 solution at 25℃ was amounted to 65% of theoretical value.