| Share
 

fire clay

fire clay, clay that has a high degree of resistance to heat. By the best standards it should have a fusion point higher than 1,600°C. The term "fire clay" is commonly held to exclude kaolin and other refractory potter's clays. Fire clay should contain high percentages of silica and alumina, with as little as possible of such impurities as lime, magnesia, soda, and potash, which lower the fusion point of the clay. Fire clay often forms the bed layer of earth under seams of coal. Two types are recognized—flint clay, exceedingly hard, nonplastic, and resembling flint in appearance, occurring in the United States; and plastic fire clay. The principal uses of fire clay are in the manufacture of firebrick and of various accessory utensils, such as crucibles, saggers, retorts, and glass pots, used in the metalworking industries.

The Columbia Electronic Encyclopedia, 6th ed. Copyright © 2012, Columbia University Press. All rights reserved.

More on fire clay from Infoplease:

See more Encyclopedia articles on: Geology and Oceanography


Premium Partner Content
HighBeam Research
Documents Images and Maps Reference
(from Newspapers, Magazines, Journals, Newswires, Transcripts and Books)

Research our extensive archive of more than 80 million articles from 6,500 publications.

Additional search results provided by HighBeam Research, LLC. © Copyright 2005. All rights reserved.

24 X 7

Private Tutor

Click Here for Details
24 x 7 Tutor Availability
Unlimited Online Tutoring
1-on-1 Tutoring