Gypsum powder is a natural product found in deposits throughout the United States. It begins as a soft, white mineral rock and is processed to make a dry powder. Naturally occurring gypsum is composed of calcium, sulfur, oxygen and hydrogen. Gypsum powder is mainly used in building materials such as drywall, but it is also useful in agriculture as a soil fertilizer and conditioner. Gypsum can be also be used as a food additive to enhance the texture of ingredients in processed foods.
Gypsum Chemical Formula
Gypsum is the common name for the mineral calcium sulfate, which has a chemical formula CaSO4. Gypsum bonds easily with water and is usually found in its natural state as hydrated calcium sulfate, with a chemical formula of CaSO4.2H20. Gypsum is a soft mineral that usually appears white or gray and is composed of translucent crystals. Gypsum deposits are found as sediment in areas that were once covered by water. When rock gypsum is heated, it releases the water molecules bonded to it, and the resulting product is anhydrous gypsum, a dry powder.
Building Materials: Ancient and Modern
The most common uses of gypsum powder are in building materials. Gypsum has been used for centuries to decorative elements for buildings. Pure white rock gypsum is also known as alabaster and has been used to make carved statues and sculptures. The ancient Greeks used translucent gypsum crystals to make windows. Gypsum powder mixed with water makes plaster of Paris, a molding material used to make ornate fixtures to adorn buildings as well as a coating for walls. Ancient builders also used gypsum to enhance pigments used to paint structures.
Nearly all modern homes and buildings use gypsum in the form of wall board, also known as gypsum board, drywall or sheet rock. Americans homes typically contain tons of gypsum in the form of drywall. It is attached to wooden framing to make walls and ceilings. Gypsum powder mixed with water becomes hardened and rock-like when dried. The hardened gypsum is pressed between sheets of paper to form slabs of drywall. Drywall makes an inexpensive building material that can easily be cut to size. It provides a sound barrier and is resistant to fire.
Gypsum powder is also added to cement and paints used in building construction and finishing. In cement and concrete mixes, gypsum helps to increase the time it takes for concrete and cement to dry and harden, resulting in a more stable structure. In paint, gypsum powder is used a filler to adhere to the pigments and improve the paint’s texture.
Soil Conditioning and Fertilizing
Gypsum powder is used in agriculture as a soil conditioner and fertilizer. Applying it to soil as a fertilizer contributes calcium and sulfur, two nutrients used by plants. Gypsum powder is especially beneficial to corn and soybeans, which need a lot of sulfate in the soil to thrive. The affinity gypsum mineral has for water molecules increases soil’s ability to hold water when the gypsum is worked into the soil because the positively charged calcium ions (Ca2+) in gypsum displace the positively charged sodium ions (Na+) present in the soil.
FDA-Approved Food Additive
Because gypsum is considered generally safe for humans, it can be used in small amounts in food and beverage production. In the food industry, gypsum may be used as an anti-caking agent, drying agent, dough-strengthener, firming agent, color enhancer, stabilizer and thickener. Food products that may be made with gypsum include baked goods, frosting, candies, ice cream and other frozen dairy products, puddings, gelatins and pasta. Gypsum powder is also a non-active ingredient in toothpaste.
About the Author
A.P. Mentzer graduated from Rutgers University with degrees in Anthropology and Biological Sciences. She worked as a researcher and analyst in the biotech industry and a science editor for an educational publishing company prior to her career as a freelance writer and editor. Alissa enjoys writing about life science and medical topics, as well as science activities for children
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