Introduction and Historic Overview

Products such as bricks, whitewares, cements, glasses, and alumina are considered traditional ceramics because they are derived from either (1) crude minerals taken directly from deposits or (2) refined minerals that have undergone beneficiation to remove mineral impurities and control physical characteristics [1]. Most traditional ceramics are fabricated using substantial amounts of clay. Clays are distinguished from other naturally occurring raw materials by their development of plasticity when mixed with water [2]. As a common mineral constituent of the Earth’s crust, clays have been used to fabricate useful objects for countless generations, with earthenware ceramics dating back to at least 5000 B. C. [3]. Clay-based ceramic objects were used by virtually all pre-historic cultures for practical, decorative, and ceremonial pur­poses. Analysis of shards from these objects is our primary means of gathering infor­mation on these civilizations. The hard porcelains produced by the ancient Chinese (~575 A. D. more than 100 years before their European counterparts) stand as the ulti­mate achievement in the field of ceramics prior to the industrial revolution [4,5]. Clay minerals continue to be widely utilized in the production of traditional ceramics and other products due to their ubiquity and low cost combined with properties that include plasticity during forming, rigidity after drying, and durability after firing [6].

For much of the twentieth century, the ceramics industry centered on the utilization of clays and other silicate minerals. Ceramic engineering educational programs and organizations such as the American Ceramic Society were founded to serve industries

J. F. Shackelford and R. H. Doremus (eds.), Ceramic and Glass Materials: 111

Structure, Properties and Processing.

© Springer 2008

based on the utilization of silicate or aluminosilicate minerals [7]. As clay-based tradi­tional ceramics became commodity items in the middle and latter portions of the twentieth century, the focus of educational programs and industrial development shifted away from mineral utilization and toward advanced ceramics, which include phase-pure oxides, electronic materials, and non-oxide ceramics. The raw materials for these prod­ucts are classified as industrial inorganic chemicals because they have been chemically processed to improve purity compared with the crude or refined minerals used to produce traditional ceramics [1]. Despite the shift in focus away from traditional ceramics, the production of clays has not fallen significantly over the past 30 years (Fig. 1). At a current average cost of more than $30 per ton (Fig. 2), clay production was a $1.3 billion

Introduction and Historic Overview

Fig. 1 Clay production from 1900 to 2002 [8]

Introduction and Historic Overview

Fig. 2 Cost of clay per ton from 1900 to 2002 [8]

industry in 2002, based on 40.7 million metric tons [8]. Traditional ceramics still account for a significant fraction of the total industry with production in the nonmetallic minerals sector that produced approximately $95 billion in goods during 2001 [9].