Preparation of a High-Silicon ZSM-5 Molecular Sieve Using Only Coal Gangue as the Silicon and Aluminum Sources

Abstract

The traditional preparation of ZSM-5 molecular sieves relies on chemical reagents to provide silicon and aluminum sources, which are limited as raw materials and cannot be commonly used in production practice. Using coal gangue as the raw material and using medium-temperature chlorination roasting and the pressure acid leaching process to control the silicon–aluminum ratio [n(Si/Al)] of coal gangue, a ZSM-5 molecular sieve was prepared using the alkali melting hydrothermal method. The pressure acid leaching process solved the limitation that kaolinite and mica cannot simultaneously be activated. Under optimal conditions, the n(Si/Al) of the coal gangue increased from 6.23 to 26.14 and complied with the requirements for the synthesis n(Si/Al) of a ZSM-5 molecular sieve. The effect of n(Si/Al) on the preparation of the ZSM-5 molecular sieve was studied. Finally, spherical granular ZSM-5 molecular sieve material with a microporous specific surface area of 169.6329 m2/g, an average pore diameter of 0.6285 nm, and a pore volume of 0.0988 cm3/g was prepared. Providing ideas for the high-value utilization of coal gangue, it is significant for solving the problem of coal gangue solid waste, as well as the problem of ZSM-5 molecular sieve feed stock.

Medium-temperature calcination and acid pressure leaching extract the Al2O3 from coal gangue: activation mechanism and kinetic analysis

“…6–8 Coal gangue can be used for the production of chemical products such as alumina, 9 aluminum sulfate, 10 and polymeric aluminum chloride, 11 as well as for the preparation of molecular sieve materials. 12 Therefore, coal gangue can be used as a substitute for bauxite to provide raw materials for the development of the downstream aluminum industry. Currently, the amount of coal gangue accumulation has reached 45–50 Bt.…”

A Novel Strategy for the Preparation of Supported Pd as an Efficient Catalyst for the Hydrogenation of Nitrobenzene in Mild Conditions

“…Until now, various materials, including carbon [14], zeolites [15][16][17], metal oxide [18][19][20], and metal-organic frameworks [21], have been explored as supports for the synthesis of supported noble metal catalysts. In these materials, zeolites gain much attention because of their high surface area, high stability, and tunable porosity and acidity [22][23][24]. In the literature, many zeolites supported by noble metal catalysts were prepared by conventional impregnation [25,26] or sol-gel deposition methods [27].…”