Abstract

Filtration experiments were carried out using both an AlF3 slurry-coated and an uncoated Al2O3 ceramic foam filter to study the removal of nonmetallic inclusions and impurity elements. the results showed that the 30-ppi ceramic foam filter removed up to 85 pct inclusions from aluminum. Several pictures of two- and three-dimensional morphologies of both nonmetallic and intermetallic inclusions also have been presented. the following contributing mechanisms for the removal of nonmetallic inclusions in the deep-bed filtration mode are proposed: (1) collision with walls and interception effect and (2) the formation of both intermetallic and nonmetallic inclusion bridges during filtration. Fluid dynamics modeling of inclusion attachment to the filter walls showed that most inclusions, especially those with larger sizes, are entrapped at the upper part of the filter, whereas smaller inclusions are dispersed well throughout the filter. the calculated inclusions removal fractions for the 30-ppi filter showed that almost all inclusions >125 μm are removed, and inclusions ~5 μm in size are removed up to 85 pct. the interfacial energy between two collided same-size inclusions was calculated, indicating that a strong clustering of inclusions may result within the filter window. Magnesium impurities were removed up to 86 pct by the AlF3 slurry-coated filter. the filter acted in active filtration mode in addition to the contribution of the air oxidation of dissolved [Mg], which was calculated to be 13 pct. the total mass transfer coefficient of dissolved [Mg] to the reaction interface was calculated to be 1.15 x 10-6 m/s. © 2010 the Minerals, Metals & Materials Society and ASM International.

Department(s)

Materials Science and Engineering

Comments

Missouri University of Science and Technology, Grant None

International Standard Serial Number (ISSN)

1073-5615

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2024 Springer, All rights reserved.

Publication Date

01 Aug 2010

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