Title

Preparation of Inorganic Compounds At Near Room Temperature by the Direct Conversion of Borate Glass in Solutions of the Corresponding Anions

Abstract

The preparation of alkaline-earth chromate, selenite, and stannate compounds at near room temperature by the direct conversion of borate glass in aqueous solutions of the corresponding anions was investigated. Borate glass particles (150-300 μm) with the composition 20Na 2O. 20CaO. 60B 2O 3 or 20Na 2O. 20BaO. 60B 2O 3 (mol%) were prepared by conventional methods and immersed in dilute solutions of K 2CrO 4, K 2SeO 3, or K 2SnO 3 at 37°C. The conversion of the glasses was monitored using weight loss and pH measurements, while X-ray diffraction (XRD), X-ray fluorescence, and scanning electron microscopy were used to characterize the structure and composition of the products. After a reaction for 140-320 h, porous crystalline products identified by XRD as CaSeO 3.H 2O, CaSnO 3.3H 2O, BaCrO 4, and BaSeO 3 were obtained. The conversion of fibers (0.5-1.0 mm in diameter) of the Na 2O-BaO-B 2O 3 glass in K 2CrO 4 solution was pseudomorphic. The kinetics and mechanisms of the conversion process, as well as the structure of the products, are discussed.

Department(s)

Mining and Nuclear Engineering

Second Department

Materials Science and Engineering

Keywords and Phrases

Alkaline earths; Aqueous solutions; Borate glass; Conventional methods; Conversion process; Dilute solutions; Direct conversions; Kinetics and mechanisms; Ph measurements; Room temperatures; Stannate; Weight loss; X-ray diffractions; X-ray fluorescences; XRD

International Standard Serial Number (ISSN)

27820

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2008 American Ceramic Society, All rights reserved.


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