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Calcium sulfate (or calcium sulphate) is the inorganic compound with the formula CaSO 4 and related hydrates. In the form of γ- anhydrite (the anhydrous form), it is used as a desiccant . One particular hydrate is better known as plaster of Paris , and another occurs naturally as the mineral gypsum .
Phosphogypsum (PG) is the calcium sulfate hydrate formed as a by-product of the production of fertilizer, particularly phosphoric acid, from phosphate rock. It is mainly composed of gypsum (CaSO 4 ·2H 2 O).
Gypsum is a soft sulfate mineral composed of calcium sulfate dihydrate, with the chemical formula CaSO 4 ·2H 2 O. [4] It is widely mined and is used as a fertilizer and as the main constituent in many forms of plaster, drywall and blackboard or sidewalk chalk.
This transformation is reversible, with gypsum or calcium sulfate hemihydrate forming anhydrite by heating to around 200 °C (400 °F) under normal atmospheric conditions. [6] Anhydrite is commonly associated with calcite, halite, and sulfides such as galena, chalcopyrite, molybdenite, and pyrite in vein deposits.
Other common desiccants include activated charcoal, calcium sulfate, calcium chloride, and molecular sieves (typically, zeolites). Desiccants may also be categorized by their type, either I, II, III, IV, or V. These types are a function of the shape of the desiccant's moisture sorption isotherm. Alcohols and acetones are also dehydrating agents.
10% calcium gluconate solution (given intravenously) is the form of calcium most widely used in the treatment of low blood calcium.This form of calcium is not as well absorbed as calcium lactate, [12] and it only contains 0.93% (93 mg/dL) calcium ion (defined by 1 g weight solute in 100 mL of solution to make 1% solution w/v).
Calcium sulfite, or calcium sulphite, is a chemical compound, the calcium salt of sulfite with the formula CaSO 3 ·x(H 2 O). Two crystalline forms are known, the hemihydrate and the tetrahydrate, respectively CaSO 3 ·½(H 2 O) and CaSO 3 ·4(H 2 O). [2] All forms are white solids. It is most notable as the product of flue-gas desulfurization.
For sodium sulfate, 250 to 500 mg/litre, with calcium sulfate at 250 to 1000 mg/litre and magnesium sulfate at 400 to 600 mg/litre. A study by Zoeteman found that having 270 mg of calcium sulfate and 90 mg of magnesium sulfate actually had improved the taste of the water.