Continuous rotary kiln calcination of YBaCuO precursor powders

A bench rotary kiln was used to produce pure YBa sub(2)Cu sub(3)O sub(6+x) by continuous calcination of spray-roasted precursor powder using a countercurrent air flow to avoid a reaction between evolved CO sub(2) and the product. Product agglomeration caused a spread in the velocity distribution, re...

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Bibliographic Details
Published in:Industrial & engineering chemistry research 1994-02, Vol.33 (2), p.421-427
Main Authors: SHELUKAR, S. D, KESHAVA SUNDAR, H. G, SEMIAT, R, RICHARDSON, J. T, LUSS, D
Format: Article
Language:English
Subjects:
360201 - Ceramics, Cermets, & Refractories- Preparation & Fabrication
ALKALINE EARTH METAL COMPOUNDS
Applied sciences
BARIUM COMPOUNDS
BARIUM OXIDES
CALCINATION
CHALCOGENIDES
Chemical industry and chemicals
CHEMICAL REACTIONS
COPPER COMPOUNDS
COPPER OXIDES
DECOMPOSITION
Exact sciences and technology
HIGH-TC SUPERCONDUCTORS
Industrial chemicals
Inorganic industry
MATERIALS SCIENCE
OXIDES
OXYGEN COMPOUNDS
PYROLYSIS
SUPERCONDUCTORS
SYNTHESIS
THERMOCHEMICAL PROCESSES
TRANSITION ELEMENT COMPOUNDS
YTTRIUM COMPOUNDS
YTTRIUM OXIDES
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Summary:A bench rotary kiln was used to produce pure YBa sub(2)Cu sub(3)O sub(6+x) by continuous calcination of spray-roasted precursor powder using a countercurrent air flow to avoid a reaction between evolved CO sub(2) and the product. Product agglomeration caused a spread in the velocity distribution, requiring the use of extra calcination for a pure product. High-purity YBa sub(2)Cu sub(3)O sub(6.6) was obtained at 940 degree C for 0.9 vol% solid loading, an average residence time of 75 min, and N theta (N identical with rotation rate, theta identical with inclination) between 3 and 4.5 rpm deg. However, at a residence time of 77 min, increased product agglomeration at 2.5 rpm deg caused incomplete conversion to YBa sub(2)Cu sub(3)O sub(6.6). Increasing the average residence time above 75 min increased the oxygen content of the product, with pure orthorhombic YBa sub(2)Cu sub(3)O sub(6.9) forming at 160 min. Due to reaction and temperature induced changes in particle size and shape, existing correlations cannot predict the dependence of the average solid residence time on the operating conditions.
ISSN:0888-5885
1520-5045
DOI:10.1021/ie00026a038