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Geoscience ›› 2006, Vol. 20 ›› Issue (4): 657-662.

• Engineering Geology and Environmental Geology • Previous Articles     Next Articles

Sintering Reaction of Nepheline Syenite: Thermodynamic Analysis and Experimental Study

WANG Fang, MA Hong-wen, XU Jin-ming, SU Yu-zhu   

  1. National Laboratory of Mineral Materials, China University of Geosciences,Beijing100083,China
  • Received:2006-08-09 Revised:2006-10-19 Online:2006-04-20 Published:2006-04-20

Abstract:

Nepheline syenite is an important kind of mineral resource rich inK2O, Al2O3and SiO2. Thermodynamic calculation shows that the temperature of the sintering reaction is around 800 K(527 ℃), with sodium carbonate as the additive, and the products are mainly NaAlSiO4, KAlSiO4 and Na2SiO3. The sintering experimental results show that the decomposition temperatures of the major aluminosilicate minerals in the nepheline syenite are ranging from 1,073 to 1,123 K(800-850 ℃), and the products are those as expected. The decomposition rate of minerals in the nepheline syenite is over 95%. Leaching experiments of the sintered products by acidic solution show that the separation of silica and alumina by the current procedure is superior, with extraction rates of SiO2, Al2O3 and K2O up to 91.4%, 92.2% and 92.5% respectively. The technique developed in this paper is therefore a process with less energy and raw mineral resource consumptions, and cleaning production, compared with the Russian limestone-sintering technique.

Key words: nepheline syenite, sodium carbonate, sintering reaction, separation of silica and alumina, alumina

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