Synthesis of NaY Zeolite Using Mixed Calcined Kaolins

Abstract

Abstract. Kaolin is one of several types of clay minerals. The most common crystalline phase constituting kaolin minerals is kaolinite, with the chemical composition Al 2 Si 2 O 5 (OH) 4 . Kaolin is mostly used for manufacturing traditional ceramics and also to synthesize zeolites or molecular sieves. The Si-O and Al-O structures in kaolin are inactive and inert, so activation by calcination is required. This work studies the conversion of kaolin originating from Bangka island in Indonesia into calcined kaolin phase as precursor in NaY zeolite synthesis. In the calcination process, the kaolinite undergoes phase transformations from metakaolin to mullite. The Bangka kaolin is 74.3% crystalline, predominantly composed of kaolinite, and 25.7% amorphous, with an SiO 2 /Al 2 O 3 mass ratio of 1.64. Thermal characterization using simultaneous DSC/TGA identified an endothermic peak at 527 °C and an exothermic peak at 1013 °C. Thus, three calcination temperatures (700, 1013, and 1050 °C) were selected to produce calcined kaolins with different phase distributions. The best product, with 87.8% NaY zeolite in the 54.7% crystalline product and an SiO 2 /Al 2 O 3 molar ratio of 5.35, was obtained through hydrothermal synthesis using mixed calcined kaolins with a composition of K 700C : K 1013C : K 1050C = 10 : 85 : 5 in %-mass, with seed addition, at a temperature of 93 °C and a reaction time of 15 hours.

Kaolin as a Source of Silica and Alumina For Synthesis of Zeolite Y and Amorphous Silica Alumina

“…The main purpose of this paper is to improve efficiency of the synthesis process of zeolite Y from kaolin that has been done previously [7][8], by substituting the supply of porous silica through the process of leaching metakaolin rather than calcinating of kaolin at high exothermic temperature. Furthermore, alumina-rich liquids were be used as nutrients for synthesis of ASA.…”

Karakterisasi Stabilitas Termal Kaolin Tatakan Kalimantan Selatan

“…amorf. Peristiwa eksotermik terjadi pada rentang suhu 925 • C hingga 1100 • C, dan puncaknya terjadi pada suhu 977,5 • C dimana dalam peristiwa ini akan terbentuk kembali fasa kristalin seperti spinel dan silica amorf [14]. Keadaan paling stabil teramati berdasarkan kurva DSC-TGA adalah antara rentang suhu 700-900 • C, untuk itu suhu kalsinasi diputuskan pada rentang suhu tersebut dan akan dipelajari efek apa yang akan terjadi.…”