Acta Phys. -Chim. Sin. ›› 2018, Vol. 34 ›› Issue (2): 168-176.doi: 10.3866/PKU.WHXB201707111

• ARTICLE • Previous Articles     Next Articles

Thermodynamics of the Hydrothermal Decomposition Reaction of Potassic Syenite with Zeolite Formation

Changjiang LIU1,Hongwen MA1,*(),Pan ZHANG2   

  1. 1 School of Materials Science and Technology, China University of Geosciences, Beijing 100083, P. R. China
    2 Blue Sky Technology Corporation, Beijing 100083, P. R. China
  • Received:2017-06-05 Published:2017-11-13
  • Contact: Hongwen MA E-mail:mahw@cugb.edu.cn
  • Supported by:
    Fundamental Research Funds for the Central Universities(2652015371);China Geological Survey Project(12120113087700)

Abstract:

The thermodynamics of hydrothermal decomposition reaction of potassic syenite, collected from Anhui province, China, with the formation of zeolites was studied in this work.The phase equilibrium model of the potassic syenite-NaOH-H2O hydrothermal system was constructed by the combination of "mixed solvent electrolyte model" and thermodynamic data of mineral end-members, as well as zeolites species, which was calculated from the"polymer model".According to the Gibbs free energy of reaction, the decomposition of potassic syenite into hydroxycancrinite, analcime, zeolite P, and zeolite A occurs spontaneously within the temperature range of 160-300℃.The formation conditions of hydroxycancrinite and analcime were predicted from the simulation of phase equilibrium by OLI Analyzer 9.3 software.After experimental verification, analcime (regular tetragonal trisoctahedron, ~50 μm) and hydroxycancrinite (columnar crystals, ~20 μm in length, 500 nm-1 μm in diameters) were respectively obtained with >97% K2O leaching.

Key words: Potassic syenite, Alkali-hydrothermal method, Zeolite, Chemical equilibrium, Thermodynamics

MSC2000: 

  • O641