Synthesis and characterization of zeolite Y and ZSM-5 from Nigerian Ahoko Kaolin using a novel, lower temperature, metakaolinization technique

Abstract

Zeolite Y was synthesised, for the first time, using Nigerian Ahoko kaolin. In addition, a novel metakaolinization technique was used to produce the necessary reactant phase. The first step involves the refining of the raw kaolin sample, which removes a substantial amount of quartz, a major impurity present in all kaolin including Ahoko kaolin. The second step, metakaolinization, was carried out at a significantly lower temperature and for a shorter time than in previous studies. The method for the production of metakaolin, based on rapidly exposing a sample of refined kaolin to elevated temperature was investigated in this work. Metakaolin was obtained after 6 min of exposure at 600 °C. The metakaolin produced was then used to synthesis zeolite Y and ZSM-5 using conventional hydrothermal treatment and the shortened thermal treatment cycle was shown to be effective for commercial kaolin as demonstrated by the synthesis of zeolite A.