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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).
Microbiologically induced calcium carbonate precipitation (MICP) is a bio-geochemical process that induces calcium carbonate precipitation within the soil matrix. [1] Biomineralization in the form of calcium carbonate precipitation can be traced back to the Precambrian period. [ 2 ]
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 .
900 to 1050 °C – the remaining calcium carbonate decomposes to calcium oxide (CaO) and CO 2. 1300 to 1450 °C – partial (20–30%) melting takes place, and belite reacts with calcium oxide to form alite (Ca 3 O·SiO 4) (also known as C3S in the Cement Industry). Typical clinker nodules. Alite is the characteristic constituent of Portland ...
The calcium cycle is a transfer of calcium between dissolved and solid phases. There is a continuous supply of calcium ions into waterways from rocks, organisms, and soils. [1] [2] Calcium ions are consumed and removed from aqueous environments as they react to form insoluble structures such as calcium carbonate and calcium silicate, [1] [3] which can deposit to form sediments or the ...
The production of sulfuric acid from anhydrous calcium sulfate produces calcium silicates. [9] Upon being mixed with shale or marl, and roasted at 1400 °C, the sulfate liberates sulfur dioxide gas, a precursor to sulfuric acid. The resulting calcium silicate is used in cement clinker production. [10] 2 CaSO 4 + 2 SiO 2 + C → 2 CaSiO 3 + 2 SO ...
Sulfite pulps now account for less than 10% of the total chemical pulp production [3] and the number of sulfite mills continues to decrease. [5] [6] [7] Magnesium was the standard counter ion until calcium replaced it in the 1950s.
The benefits of improving soil structure for the growth of plants, particularly in an agricultural setting, include: reduced erosion due to greater soil aggregate strength and decreased overland flow; improved root penetration and access to soil moisture and nutrients; improved emergence of seedlings due to reduced crusting of the surface; and ...