CGC is an integrated of companies consisting of mining operations, transportation, paper mills, manufacturing and distribution. The following are the main raw materials we use in many of our products for the construction business.
Plaster of Paris is de-hydrated gypsum. Gypsum is a naturally forming non-metallic mineral, found as a rock or sand composed of 70.1% calcium sulphate and 20.9% water by weight. Its chemical formula is CaSO4 • 2H2O.
Gypsum is found naturally in most parts of the world. In addition to mined gypsum there is ‘Byproduct’ gypsum. This product has several names but it basically is chemically produced gypsum (not mined) or a byproduct, created during manufacturing, industrial, or chemical processes. This byproduct gypsum is identical, chemically (CaSO4 • 2H2O) to natural (mined) gypsum. This byproduct gypsum is usually referred to by its production processes. Some of the various types of byproduct gypsum are flue-gas desulfurization (FGD) gypsum, fluorogypsum, citrogypsum, phosphogypsum, and titanogypsum.
Of these byproduct gypsums, Flue-gas desulfurization (FGD) gypsum is the most suitable for the production of drywall. For more information on FGD Gypsum, download our EPA Wallboard Review.
CGC makes our own paper. The paper is used as the front and back face surfaces of Sheetrock Brand gypsum panels and has been made with 100% recycled paper since the 1970s. We do not use bleach when making our papers.
Currently, CGC operates four paper mills across the United States in Otsego, Mich.; Galena Park, Texas; N. Kansas City, Mo.; and Oakfield, NY. Please note that for manufacturing optimizations, not all mills make paper for all plants or types of panels. In addition, rail is used for transportation to our panel plants when available.
CGC currently operates two facilities where we manufacture wool as the base mat for USG Acoustical Ceiling panels and tiles and USG Micore® mineral fiber panels. USG uses only steel blast furnace secondary slag material due to its controlled trace elements and consistency. Slag wool is made from recycled blast furnace slag — a by-product of steel production and other similar industries. The slag accounts for a minimum of 88% of the total final wool produced by weight (depending on specific product specification); the other main additive used in the production of our wool is granite, accounting for about 6% and recycled brick chips (3%).