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Surface and Bulk Crystallization of Glass‐Ceramic in the Na 2 O‐CaO‐ZnO‐PbO‐Fe 2 O 3 ‐Al 2 O 3 ‐SiO 2 System Derived from a Goethite Waste
Author(s) -
Romero Maximina,
Rincón Jesús Ma.
Publication year - 1999
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.1999.tb01913.x
Subject(s) - materials science , magnetite , microstructure , crystallite , crystallization , goethite , chemical engineering , transmission electron microscopy , mineralogy , scanning electron microscope , ceramic , precipitation , glass ceramic , metallurgy , composite material , nanotechnology , adsorption , chemistry , physics , meteorology , engineering
A goethite waste from zinc hydrometallurgical processes has been used to produce a glass‐ceramic in the Na 2 O‐CaO‐ZnO‐PbO‐Fe 2 O 3 ‐Al 2 O 3 ‐SiO 2 system. The surface and bulk microstructure of this glass‐ceramic have been studied by using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The surface was comprised of crystalline and glassy areas. Two different types of crystalline growth and two morphologies were observed in the crystallized and glassy zones, respectively. The bulk microstructure was composed of a homogeneously distributed dendritic network comprised of small crystallites of magnetite. A glassy matrix was observed surrounding the magnetite network. Further heat treatment produced the precipitation of a nonstoichiometric zinc ferrite with magnetite crystals, being the nucleating agents of the secondary phase.