FIRE CLAY

Fire clay is a detrital material, either plastic or rocklike, that is often found below coal beds. Within the United States, most fire clay is of Pennsylvanian Age, scattered from Virginia to Missouri. Fire clay contains high percentages of alumina and silica. Low concentrations of iron oxide, lime, magnesia and alkalies enable the material to withstand high temperatures. Fire clay is composed mainly of kaolinite and most often is mined by openpit methods. Once kiln-processed, fire clay ranges from buffs to grays in color. Production Fire clay was the dominant clay type mined in the United States prior to the 1940s and accounted for nearly 70 percent of the total clay tonnage produced from 1900 through 1939. Domestic production of fire clay (the quantity sold or used by producers) increased sharply from the beginning of U.S. involvement in World War II through the immediate post-war period, peaking at 10.8 Mt in 1951. The trend reversed in 1956 and was followed by several years of decreasing rates of production. In every year since 1986, fire clay production has been lower than that in 1900 and reached a low of 183 kt in 2012. During the past five years, fire clay production gradually increased from 567 kt in 2018 to an estimated 720 kt in 2022. In 2022, fire clay production accounted for about 3 percent of total clay produced domestically. In 2022, six companies (The Belden Brick Co., Christy Minerals Co., General Shale Brick Inc., Harbison Walker International, Resco Products Inc. and Triangle Brick Co.) were thought to mine fire clay in four states (Colorado, Missouri, North Carolina and Ohio). Other companies may or may not have produced fire clay as year-to-year output recently became variable as common clay producers entered and exited the marketplace in response to short-term demands. Fire clay production was estimated to have increased by 7 percent to 720 kt in 2022 compared with 675 kt in 2021. Reliable data on global output of fire clay are not available because many countries either do not report clay production or do not distinguish between fire clay and other clay types. Consumption Structural concrete was estimated to be the leading market of fire clay in 2022. Other markets for fire clay included common brick, fire brick, floor and wall tile, portland cement, refractory grogs and calcines, and miscellaneous uses. The U.S. Geological Survey withholds data related to specific market consumption of fire clay to avoid disclosing company proprietary data. Prices The average unit value of fire clay was estimated to be unchanged at $12/t in 2022 from that of 2021. Fire clay prices have trended downward since 2007, when the average unit value was $42/t. Over the past five years (2018-2022) the average unit value of fire clay was estimated to be $12/t. According to the U.S. Census Bureau, the average unit value of imported fire clay in 2022 was $206/t, compared with $459/t in 2021. The average unit value of exported fire clay was $504/t in 2022, compared with $463/t in 2021. Average unit values for imports typically fluctuate more than the average unit values for exports owing to smaller, high-value shipments. Foreign trade According to the U.S. Census Bureau, fire clay exports decreased in 2022 to 158 kt valued at $47.4 million from 210 kt valued at $52.9 million in 2021. The principal destinations for U.S. exports of fire clay in 2022 were the Netherlands (34 percent), Taiwan (15 percent), Mexico (13 percent), Germany (8 percent) and Japan (6 percent). Imports of fire clay increased in 2022 to 14 kt valued at $2.9 million compared with 6 kt valued at $2.8 million in 2021. China (62 percent) and Spain (32 percent) were the leading sources of fire clay imports in 2022. Outlook The fire clay industry is mature and is not expected to experience large changes. Fire clay production is expected to remain relatively stable over the next several years supported by applications that use refractory brick, such as the aluminum, cement, glass, heavy-clay products, lime and steel industries.

FIRE CLAY

Authored by:
Kristi J. Simmons

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From sessions to strategy: Revealing long-term and emerging innovation trends in data analytics, intelligent systems and automation

Mining education gets federal boost as industry faces workforce crunch

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To view the past issues of the UCA magazine you must be a member of SME/UCA.

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