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Silicate minerals are rock-forming minerals made up of silicate groups. They are the largest and most important class of minerals and make up approximately 90 percent of Earth's crust. [1] [2] [3] In mineralogy, silica (silicon dioxide, SiO 2) is usually considered a silicate mineral rather than an oxide mineral. Silica is found in nature as ...
The silica cycle plays an important role in long term global climate regulation. The global silica cycle also has large effects on the global carbon cycle through the carbonate-silicate cycle. [43] The process of silicate mineral weathering transfers atmospheric CO 2 to the hydrologic cycle through the chemical reaction displayed above. [4]
When treated with calcium oxides and water, silicate minerals form Portland cement. Equilibria involving hydrolysis of silicate minerals are difficult to study. The chief challenge is the very low solubility of SiO 4 4-and its various protonated forms. Such equilibria are relevant to the processes occurring on geological time scales.
In some compositions, at high pressures without water crystallization of enstatite is favored, but in the presence of water at high pressures, olivine is favored. [12] Granitic magmas provide additional examples of how melts of generally similar composition and temperature, but at different pressure, may crystallize different minerals.
Sodium silicate is also the technical and common name for a mixture of such compounds, chiefly the metasilicate, also called waterglass, water glass, or liquid glass. The product has a wide variety of uses, including the formulation of cements , coatings, passive fire protection , textile and lumber processing, manufacture of refractory ...
Weathering is the deterioration of rocks, soils and minerals (as well as wood and artificial materials) through contact with water, atmospheric gases, sunlight, and biological organisms. It occurs in situ (on-site, with little or no movement), and so is distinct from erosion , which involves the transport of rocks and minerals by agents such as ...
These substances break down into dissolved ions as a result. For example, calcium silicate (CaSiO 3), or wollastonite, reacts with carbon dioxide and water to yield a calcium ion, Ca 2+, a bicarbonate ion, HCO 3 −, and dissolved silica. This reaction structure is representative of general silicate weathering of calcium silicate minerals. [9]
The carbonate that dissolved is therefore pulled out from the system while the silica precipitated recrystallizes into various silicate minerals, depending on the silica phase. [17] The solubility of silica strongly depends on the temperature and pH value of the environment [ 3 ] where pH9 is the controlling value. [ 1 ]