Development And Characterization Of Zeolitey From A Nigerian Local Raw Material.

ABSTRACT

Zeolites are important chemical materials used in chemical processes. The manufacture of the materials usually involves the use of expensive chemicals. This study involves the use of Elefun Nigerian Kaolin (ENK) as precursor material for the development of zeolite Y. The synthesis of zeolite Y was successful following a sequence: collection of raw kaolin clay from Elefun area of Ogun state, Nigeria; subjecting it to, calcination, partial dealumination and final hydrothermal synthesis. The raw clay was refined using sedimentation technique to recover 98 percent kaolin. Both conventional and novel methods

of metakaolinization technique were used to convert kaolin into the reactive metastable phase. Amorphous metakaolin was obtained at a temperature of 850oC at residence time of 6 hours. The percentage of the alumina in the metakaolin was reduced through reaction with

sulphuric acid to give Silica/Alumina molar ratio of 4.7 after ageing for between seven and nine days. The unique procedure of gel formation and Crystallization to NaY zeolite was achieved after 24hours at 100oC. The NaY zeolite was modified by ion exchange process to

give a more acidic zeolite HY with improved Bronsted active acid sites.

The synthesised Zeolite HY was characterized and confirmed through the XRD pattern and the silica/alumina ratio of about 3.62 using XRF, the results were corroborated with the analytical results from both SEM (Scanning Electron Microscope) and BET (Brunauer,

Emmet and Teller). The activity of the synthesised zeolite Y was confirmed. It compared favourably to the market commercial brand through its very similar conversion in the cracking reactions of cyclohexane and Gas Oil to lighter products when tested in NNPC

Kaduna Refinery Laboratory.

Keywords: Zeolite-Y, metakaolinization, dealumination, hydrothermal, metastable phase, Bronsted, microkinectic.