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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 · 2 H 2 O).
The following chart shows the solubility of various ionic compounds in water at 1 atm pressure and room temperature (approx. 25 °C, 298.15 K). "Soluble" means the ionic compound doesn't precipitate, while "slightly soluble" and "insoluble" mean that a solid will precipitate; "slightly soluble" compounds like calcium sulfate may require heat to precipitate.
English: The temperature dependence of the solubility of calcium sulfate in pure water. 3 phases are marked: gypsum (calcium sulfate dihydrate), hemihydrate (plaster of Paris), and anhydrite. Data source: "The ASME Handbook on Water Technology for Thermal Power Systems", Paul Cohen (ed), American Society of Mechanical Engineers, 1989.
2. Na 2 CO 3 + Ca(OH) 2 ←→ 2 NaOH + CaCO 3. Calcium carbonate precipitates from the white liquor and is recovered and heated in a lime kiln where it is converted to calcium oxide (lime). 3. CaCO 3 → CaO + CO 2. Calcium oxide (lime) is reacted with water to regenerate the calcium hydroxide used in Reaction 2: 4. CaO + H 2 O → Ca(OH) 2
The tables below provides information on the variation of solubility of different substances (mostly inorganic compounds) in water with temperature, at one atmosphere pressure.
Nutrients in the soil are taken up by the plant through its roots, and in particular its root hairs.To be taken up by a plant, a nutrient element must be located near the root surface; however, the supply of nutrients in contact with the root is rapidly depleted within a distance of ca. 2 mm. [14] There are three basic mechanisms whereby nutrient ions dissolved in the soil solution are brought ...
The electric power consumption of an efficient plant is around 20 kWh per tonne of lime. This additional input is the equivalent of around 20 kg CO 2 per ton if the electricity is coal-generated. Thus, total emission may be around 1 tonne of CO 2 for every tonne of lime even in efficient industrial plants, but is typically 1.3 t/t. [14]