Abstract: Coal gasification slag is a solid waste of coal chemical industry. Because it contains a lot of silicon and aluminum elements, it can be used as raw material to synthesize high value Y zeolite material, which realizes resource utilization. Y zeolite with octahedral morphology and single phase was successfully synthesized from Ningxia Ningdong coal gasification slag by hydrothermal synthesis method induced by directing agent after acid and alkali pretreatment. The effects of acid and alkali pretreatment conditions, Si/Al ratio, H₂O/SiO₂ ratio, crystallization temperature, crystallization time and directing agent content on the crystal phase of Y zeolite synthesized from coal gasification slag were investigated in detail. XRD, XRF, SEM and FT-IR were used to analyze the properties of synthesized Y zeolite. By optimizing the process conditions, the H₂O/SiO₂ ratio is reduced to 20, the crystallization time is shortened to 24 h, and the Y zeolite product has good crystallinity, high specific surface area of 538 m²/g and total pore volume of 0.350 cm³/g.

Key words: coal gasification slag, resource utilization, single phase, Y zeolite, process optimization