Study On The Synthesis Of Zeolites From Oil Shale Ash

Zeolites are crystalline aluminosilicates with indefinitely extending three-dimensional network of aluminium and silicon tetrahedral linked by sharing of oxygen atoms.Due to their excellent ion exchange,catalytic and adsorption properties,they are widely applied in the fields of detergent industry,petrochemical industry and fine chemical industry etc.At present, the main materials used to synthesized zeolites are the chemical materials,which results in a high cost and the widely utilization has been limited.Therefore,many researchers try to seeking cheap materials for their synthesis.Based on lots of literatures of zeolites synthesis,a series of zeolites are hydrothermally synthesized successfully from the oil shale ash.Besides,the influence of treatment conditions is studied systematically.A series of zeolite products(SOD,ANA and CAN type) were synthesized by using oil shale ash and alkali solution as starting materials through the hydrothermal method.It is discussed in depth the effects of H₂O/Na₂O,Na₂O/SiO₂ molar ratio on the synthesis of zeolites.The binary crystallization phase diagram was obtained and the key parameters of synthesizing zeolites were optimized to achieve the best synthetical conditions.A modified fusion process is studied to synthesis NaA and NaX from oil shale ash.It is found that the fusion process could be utilized for the synthesis of NaX and that the addition of alumina to the fused fly ash produced single phase NaA.The result confirms that the quantity of dissolved Al species is critical for the type of zeolite formed.Converting oil shale into zeolites not only alleviates the disposal problem but also turns an waste material into a marketable commodity.