The Mullitizatiou of North Korea Kaolin at 1000°C

Abstract

Effect of additives on the mullite formation reactions of North Korea kaolin was studied. Knead-formed samples containing 20mol% of LiF, Li₂CO₃, MgF₂, MgO, CuF₂ and CuO were heated at 1000°C up to 90 days and the amount of mullite formed was determine dby X-ray diffractometry. Mullite yields (%) were as follows: without additives 8.7; when Li₂CO₃ was added, 16.5; LiF, 18; Li₂CO₃ (10mol%), 19.7; MgF₂, 20.7; MgO, 22.5; CuF₂, 27.7 and CuO, 29.3. It has been deduced that all the reaction rate curves obtained follow the Tammann's equation, where the mullite yield increases linearly with logarithm of time and reaches to a constant value α_e at a time t_e.