Paper manufacturing, chemicals used calcium carbonate

Properties Commercial grades Uses Manufacture White to grayish-white solid. Reacts with water to form calcium hydroxide. Commercial lime is available in lump, pebble, ground, and pulverized forms. One of the oldest commercial chemicals. Used in hundreds of applications. The most important uses are for making steel and chemicals, water treatment, pollution control, pulp and paper, and construction. Limestone (calcium carbonate, CaCOj) from mines or quarries is heated in a kiln (calcined). 

Food and pharmaceutical grades of calcium carbonate are covered by the Food Chemicals Codex (7) and the United States Pharmacopeia (8) and subject to U.S. Food and Dmg Administration Good Manufacturing Practices (9). Both purity requirements and test methods are available (7,8). Calcium carbonate is listed in the U.S. Code of Federal Regulation as a food additive, and is authorized for use in both paper and plastic food contact appHcations. 

Calcium carbonate is insoluble, and precipitates out during this reaction, leaving the sodium hydroxide in solution. Sodium hydroxide is a useful laboratory reagent and a very important industrial chemical. It is used in industry in the manufacture of soap, the refining of petroleum, and the manufacture of paper, textiles, rayon and cellulose film, and many other products. 

Many acids, bases, and salts occur in nature and serve a wide variety of purposes. For instance, your digestive juice contains approximately 0.10 mole of hydrochloric acid per liter. Human blood and the aqueous components of most cells are mildly acidic. The liquid in your car battery is approximately 40% H2SO4 by mass. Baking soda is a salt of carbonic acid. Sodium hydroxide, a base, is used in the manufacture of soaps, paper, and many other chemicals. Drano is solid NaOH that contains some aluminum chips. Sodium chloride is used to season food and as a food preservative. Calcium chloride is used to melt ice on... 

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