- Soda-lime glass
Soda-lime glass, also called soda-lime-silica glass, is the most prevalent type of
glass, used for windowpanes, and glass containers (bottles and jars) for beverages, food, and some commodity items. Also Pyrexbrand kitchen glassware manufactured since 1998 (when the brand was spun off under World Kitchen) is made of soda-lime glass cite web | url = http://www.sec.gov/Archives/edgar/data/1063574/000101540204001267/0001015402-04-001267.txt | title = 10-K filing, WKI Holding Co., Inc. | date = 2004 | pages = 8 | accessdate = 2006-10-22 see also: [http://www.pyrex.com Pyrex website] .] (previously, it was made of better quality, thermal shockresistant borosilicate glass).
Soda-lime glass is prepared by melting the raw materials, such as soda, lime,
silica, alumina, and small quantities of fining agents (e.g., sodium sulfate, sodium chloride) in a glass furnace at temperatures locally up to 1675°C.B. H. W. S. de Jong, "Glass"; in "Ullmann's Encyclopedia of Industrial Chemistry"; 5th edition, vol. A12, VCH Publishers, Weinheim, Germany, 1989, ISBN 3-527-20112-5, p 365-432.] The temperature is only limited by the quality of the furnace superstructure material and by the glass composition. Green and brown bottles are obtained from raw materials containing iron oxide. For lowering the price of the raw materials, pure chemicals are not used, but relatively inexpensive minerals such as trona, sand, and feldspar. The mix of raw materials is termed "batch".
Soda-lime glass is divided technically into glass used for windows, called "
float glass" or " flat glass", and glass for containers, called " container glass". Both types differ in the application, production method (float process for windows, blowing and pressing for containers), and chemical composition (see table below). Float glass has a higher magnesium oxideand sodium oxidecontent as compared to container glass, and a lower silica, calcium oxide, and aluminium oxidecontent."High temperature glass melt property database for process modeling"; Eds.: Thomas P. Seward III and Terese Vascott; The American Ceramic Society, Westerville, Ohio, 2005, ISBN 1-57498-225-7] From this follows a slightly higher quality of container glass concerning the chemical durabilityagainst water (see table), which is required especially for storage of beverages and food.
Typical compositions and properties
The following table lists some physical properties soda-lime glasses. Unless otherwise stated, the glass compositions and many experimentally determined properties are taken from one large study. Those values marked in "italic" font have been interpolated from similar glass compositions (see
calculation of glass properties) due to the lack of experimental data.
Coefficient of Restitution (glass sphere vs. glass wall): 0.97 ± 0.01 [P. Gondret, et al.: "Bouncing Motion of Spherical Particles in Fluids"; Physics of Fluids, vol. 14, 2002, no. 2, p 643-652.]
Thermal Conductivity: 0.9-1.3 W/m.K [Janssen, L.P.B.M., Warmoeskerken, M.M.C.G., 2006. "Transport phenomena data companion". Delft: VVSD.]
Hardness (Mohs Scale): 6–7Fact|date=December 2007
Knoop Hardness: 585 kg/mm2 + 20Fact|date=December 2007
Glass batch calculation
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