TAILIEUCHUNG - Encyclopedia of Global Resources part 131

Encyclopedia of Global Resources part 131 provides a wide variety of perspectives on both traditional and more recent views of Earth's resources. It serves as a bridge connecting the domains of resource exploitation, environmentalism, geology, and biology, and it explains their interrelationships in terms that students and other nonspecialists can understand. The articles in this set are extremely diverse, with articles covering soil, fisheries, forests, aluminum, the Industrial Revolution, the . Department of the Interior, the hydrologic cycle, glass, and placer mineral deposits. . | 1206 Talc Global Resources dioxide are added to extensively altered olivine- or pyroxene-rich igneous rocks and when water and silica are added to altered carbonate rocks talc forms. Talc is also found in cr ystalline schists. The mineral is found mostly in mountainous regions with China South Korea and Japan as the chief sources. Historically the Pyrenees Mountains of France were a major source of talc and contributed to the beginning of the cosmetic s industry in that country. History Talc has been used since ancient times for car ved and engraved ornaments and utensils. American Indians used steatite for making bowls pots and stoves and Eskimos used it for sculptures. Talc has become an important ingredient in many commercial products. Obtaining Talc Generally talc is obtained through open-pit mining techniques. In his book Functional Fillers for Plastics 2005 Marino Xanthos outlines the seven-to-eight-step process for obtaining talc through open-pit mining. First the overburden is removed thus exposing Talc is the softest mineral on the Mohs hardness scale. USGS the talc. The talc is then shoveled out of the mine in order to be crushed. Then it is categorized by brightness and content. The talc is ground to break it down further. For most talc this is the final procedure. However high-grade talcs such as those used in the pharmaceutical industr y require treatment with various chemical compounds. Uses of Talc In the ceramics industr y talc is used in tableware electrical porcelain and glazed wall tiles. In paints talc is used as a extender and as a pigment. It is used as a filler in paper rubber insecticides lubricants and leather salves. In cosmetics it is used in toilet powders soaps and creams with its extreme softness leading to its use as talcum powder and face powder. With revelations that talc in cosmetics might be linked to lung ovarian and skin cancers many consumers began to avoid talc-containing products. Massive slabs of talc are used for acid-proof

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