Microstructural study of synthetic alumina-magnesia spinel for refractories from natural raw materials

Author

Yu-I Eunice Chao

Abstract

"Alumina-magnesia spinel is being used increasingly as a high quality refractory material in furnace and cement rotary kiln applications, but the cost of synthetic powders and grains limits its application. Different sources of bauxite from Guyana and China, and diaspore from Missouri have been utilized to synthesize spinel for refractories in order to reduce the cost.

The purpose of this research is to examine the extent and character of spinel formation under different firing conditions and varying Al₂O₃:MgO ratios. Finely ground aluminous raw materials were mixed with hardburned magnesia in certain ratios to form spinel. X-ray analysis was used for mineralogical analysis and showed that after heating at 1550°C, spinel readily occurs together with some impurity minerals such as rutile, corundum, mullite, aluminum titanium oxide and some glassy phase.

Reflected light microscopy, scanning electron microscopy (SEM) and cathodoluminescence microscopy (CLM) were utilized in a microstructural study to determine the amount and distribution of each phase present in thirty-nine samples prepared at different firing temperatures and with different starting chemical compositions. The chemical compositions of each phase were also analyzed by an energy dispersive X-ray spectrometer (EDS).

The results of this investigation provide a better understanding of the nature of the microstructure of synthetic spinels and indicate that selection of starting raw materials is crucial in the synthesis, among all the variables which could affect the nature and the amount of phases generated"--Abstract, pages iii-iv.

Advisor(s)

Hagni, Richard D.
Moore, Robert E., 1930-2003

Committee Member(s)

Grant, S. Kerry

Department(s)

Geosciences and Geological and Petroleum Engineering

Degree Name

M.S. in Geology and Geophysics

Publisher

University of Missouri--Rolla

Publication Date

Fall 1993

Pagination

xii, 47 pages

Note about bibliography

Includes bibliographical references (pages 42-45).

Rights

© 1993 Yu-I Eunice Chao, All rights reserved.

Document Type

Thesis - Restricted Access

File Type

text

Language

English

Thesis Number

T 6641

Print OCLC #

29985743

Electronic OCLC #

993783264

Recommended Citation

Chao, Yu-I Eunice, "Microstructural study of synthetic alumina-magnesia spinel for refractories from natural raw materials" (1993). Masters Theses. 1182.
https://scholarsmine.mst.edu/masters_theses/1182