Gypsum calcium

Some products are precipitated from the fermentation broth. The insoluble calcium salts of some organic acids precipitate and are col-lec ted, and adding sulfuric acid regenerates the acid while forming gypsum (calcium sulfate) that constitutes a disposal problem. An early process for recovering the antibiotic cycloserine added silver nitrate to the fermentation broth to precipitate an insoluble silver salt. This process was soon obsolete because of poor economics and because the silver salt, when diy, exploded easily. 

Gipfelwert, m. top (or peak) value, maximum. GIpa, m. gypsum calcium sulfate plaster of Paris. >abdruck, abguss, m. plaster cast, -arbeiter, m. plasterer, gipsartig, a. gypseous. 

Sulfates Metal ion(s) + sulfate ion(s) Gypsum (calcium sulfate), raw material for making plaster of Paris Alabaster (calcium sulfate or calcium carbonate), a lapidary material... 

The action of carbonic acid on limestone produces a calcium bicarbonate solution that is exceedingly soluble in water. (For comparison, at 20°C the solubility of calcium carbonate in water is only 0.0145 g per liter while the solubility of calcium bicarbonate is 166 g per literJ ) Magnesium ions from dolomite are also released into aqueous solution according to the same mechanism. The weathering of gypsum, calcium sulfate, also releases calcium ions into natural water supplies. 

Prayon One of the Wet processes for making phosphoric acid by reacting phosphate rock with sulfuric acid. The byproduct is gypsum, calcium sulfate dihydrate. It uses a compartmentalized, multi-section, lined, concrete reactor, with finishing tanks in which the gypsum crystals mature. In 1990 one third of the wet process phosphoric acid made in the Western World was made in this way. The process was developed in 1977 by the Societe de Prayon, Belgium. Variations are known as PH2, PHI 1, and PH12. One variation uses solvent extraction with isopropyl ether and tri-n-butyl phosphate. 

One of the most impottant oxides is dihydrogen oxide, or rather water (H O). There are numerous oxygen compounds on Earth, many of them with more that two elements. They include the sihcates, which make up rocks and soil, as well as hmestone (calcium carbonate), gypsum (calcium sulfate), bauxite (aluminum oxide), and many iron oxides. 

The LeBlanc process for the manufacture of soda ash was discovered in 1773 and was used universally for many years in Europe. Salt cake (sodium sulfate) reacts with limestone to give soda ash and a troublesome side product gypsum (calcium sulfate). The process is no longer used. 

In an undated letter to J. G. Gahn, which was probably written in 1774, Scheele stated that he had precipitated alum with lime water. "When I had the right proportion of the lime water to the acid in the alum, said he, I got a precipitate of alumina and gypsum (calcium sulfate) in the solution, . . and I found neither lime or gypsum in the clear solution, but pure water (18). Thus it is evident that Scheele was at that time unaware of the presence of potash in alum. 

Although the word alabaster is sometimes applied to a kind of translucent gypsum (calcium sulfate), Egyptian alabaster was a form of calcite... 

Gypsum (Calcium Sulfate Dihydrate, Alabaster), CaSO4.2H20 raw 172.17, sp gr 2.31-2.33, white substance, mp loses 3/2HaO by 128° and rest by 167° hardness 1.5 to 2. Occurs naturally in the USA, Canada, England, France, Sicily, Switzerland etc si sol in w sol in acids, glycerin and aqueous Na3S2Oa and ammonium salts... 

Gypsum calcium sulfate dihydrate CaS04 2H20... 

IMA Europe, European site devoted to industrial minerals such as gypsum, calcium carbonate, and so forth. 

In order to obtain the desired selling qualities in Ihc finished cement, there is added to the clinker about 2% of gypsum (calcium sulfate. CaSOj 2H2O), and ihe mixture is pulverized very finely. For every ton of Portland cement shipped, over two and one-half tons of raw materials and cement clinker must be ground very finely. See Table I. 

Extraneous Mineral Substances.—Addition of extraneous mineral substances, such as gypsum, calcium carbonate, alum, heavy metals, etc., is detected as in flour q.v., section 12), and a similar method serves for the detection of sand and soil resulting from the imperfect cleaning of the grain employed. 

Some of the rock strata may contain gypsum (calcium sulfate, CaS04.2H20), anhydrite (CaS04)... 

SULEATES Sulfur and Oxygen Gypsum calcium, hydrogen PLASTER... 

Calcium was named by Humphry Davy after the material from which it was produced, calx, the Latin for limestone. Davy isolated calcium metal in 1808 by electrolysis. Although calcium never occurs in elemental form, calcium compounds are widely found in nature, particularly in limestone and gypsum. Calcium metal is used in the production and purification of other metals, while calcium compounds have thousands of uses, including chemical production, plaster, and Portland cement. 

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