General Outlook

Clays will continue to be an important industrial mineral for the foreseeable future. Clays continue to be used widely as raw materials for refractories and other traditional ceramics because of their availability, low cost, and ease of processing. However, a majority of applications for clay minerals lie outside the field of ceramics, as summa­rized in Tables 10 and 11 and described in detail in several of the references [8,14,21]. Because of this breadth of applications and continued availability of easily-mined, high-quality clay deposits, the current level of production and utilization of clay minerals should continue [8]. Production is currently stabilized around 40 million metric tons per year with an average price of approximately $30 per ton [8]. More importantly for the modern materials community, understanding the processing and characterization of traditional ceramics can provide significant insight into the struc­ture of the materials curriculum and the methods used to process and characterize advanced ceramic materials.

Table 10 Important applications for clay minerals grouped by clay type and application [8]

Clay

Application

Important Property(ies)

Kaolin

Paper

Absorbency, color

Refractories

High temperature stability

Traditional ceramics

Plasticity, fired strength

Ball Clay

Traditional ceramics

Plasticity, fired strength

Bentonite

Kitty litter

Absorbency

Foundry sand

Binding ability

Iron ore palletizing

Binding ability

Petroleum drilling mud Viscosity control, thixotropy

Fire Clay

Refractories

High temperature stability

Table 11 Other applications for clay minerals

Application

Reason for use

Absorbent

Water affinity

Adhesive

Viscosity control, inert filler

Aggregate

Low cost, low density

Cement

Al2O3 source

Clarification of beverages

Surface charge characteristics

Paint

Pigment, inert filler, viscosity control

Paper

Brightness, absorbency

Petroleum refining

Catalytic activity

Acknowledgments Many of the references used in the preparation of this chapter were donated to the Materials Science and Engineering department at MS&T from the A. P. Green Industries, Inc. corporate library. The author would like to thank Dr. David J. Wronkiewicz of the MS&T Geology and Geophysics program, Dr. Jeffrey D. Smith of the MS&T Materials Science and Engineering Department, and Ms. Jill C. Fahrenholtz for their critical reviews of various drafts of the manuscript.