| 摘要 |
PROBLEM TO BE SOLVED: To solve the problem wherein aβ-type iron silicate containing iron in its crystal lattice has low crystallinity and low resistance to heat. SOLUTION: Aβ-type iron silicate has a fluorine content of 400 ppm or less relative to the dry weight and has all or part of iron contained in aβ-skeleton structure, provided that crystalline particles of theβ-type iron silicate have a dual truncated quadrangle pyramid under a scanning electron microscope. Preferably, theβ-type iron silicate has a SiO<SB>2</SB>/Al<SB>2</SB>O<SB>3</SB>molar ratio of 300 or higher and contains at least 5.5 wt.% iron relative to the dry weight. Theβ-type iron silicate can be manufactured by carrying out hydrothermal crystallization of a raw material mixture composition comprising iron, silica, alumina and SDA (structure directing agent), particularly the composition having a (SDA/SiO<SB>2</SB>) molar ratio of 0.10-0.35. COPYRIGHT: (C)2011,JPO&INPIT |
