Intralabs Calcium Carbonate 250g - Very Fine Limestone Flour Powder

Product Information

Silicification occurs early in diagenesis, at low pH and temperature, and contributes to fossil preservation. [50] Silicification takes place through the reaction: [50] CaCO 3 + H 2 O + CO 2 + H 4 SiO 4 ⟶ SiO 2 + Ca 2 + + 2 HCO 3 − + 2 H 2 O {\displaystyle {\ce {CaCO3 + H2O + CO2 + H4SiO4 -> SiO2 + Ca Adrienne Mayor (2005), "Ancient Warfare and Toxicology", in Philip Wexler (ed.), Encyclopedia of Toxicology, vol.4 (2nded.), Elsevier, pp.117–121, ISBN 0-12-745354-7 The origin of carbonate mud, [30] and the processes by which it is converted to micrite, [45] continue to be a subject of research. Modern carbonate mud is composed mostly of aragonite needles around 5μm (0.20 mils) in length. Needles of this shape and composition are produced by calcareous algae such as Penicillus, making this a plausible source of mud. [46] Another possibility is direct precipitation from the water. A phenomenon known as whitings occurs in shallow waters, in which white streaks containing dispersed micrite appear on the surface of the water. It is uncertain whether this is freshly precipitated aragonite or simply material stirred up from the bottom, but there is some evidence that whitings are caused by biological precipitation of aragonite as part of a bloom of cyanobacteria or microalgae. [47] However, stable isotope ratios in modern carbonate mud appear to be inconsistent with either of these mechanisms, and abrasion of carbonate grains in high-energy environments has been put forward as a third possibility. [30] In 80 BC, the Roman general Sertorius deployed choking clouds of caustic lime powder to defeat the Characitani of Hispania, who had taken refuge in inaccessible caves. [23] A similar dust was used in China to quell an armed peasant revolt in 178 AD, when lime chariots equipped with bellows blew limestone powder into the crowds. [24] Most grains in limestone are skeletal fragments of marine organisms such as coral or foraminifera. [16] These organisms secrete structures made of aragonite or calcite, and leave these structures behind when they die. Other carbonate grains composing limestones are ooids, peloids, and limeclasts ( intraclasts and extraclasts [ ca]). [17]

Calcium oxide - Wikipedia Calcium oxide - Wikipedia

Coquina is a poorly consolidated limestone composed of abraded pieces of coral, shells, or other fossil debris. When better consolidated, it is described as coquinite. [40] a b c d e f Tony Oates (2007), "Lime and Limestone", Ullmann's Encyclopedia of Industrial Chemistry (7thed.), Wiley, pp.1–32, doi: 10.1002/14356007.a15_317, ISBN 978-3527306732 Limestone often contains variable amounts of silica in the form of chert or siliceous skeletal fragments (such as sponge spicules, diatoms, or radiolarians). [12] Fossils are also common in limestone. [3] Chalk is a soft, earthy, fine-textured limestone composed of the tests of planktonic microorganisms such as foraminifera, while Plaster: There is archeological evidence that Pre-Pottery Neolithic B humans used limestone-based plaster for flooring and other uses. [15] [16] [17] Such Lime-ash floor remained in use until the late nineteenth century.Croddy, Eric (2002). Chemical and biological warfare: a comprehensive survey for the concerned citizen. Springer. p.128. ISBN 0-387-95076-1. Ooids (sometimes called ooliths) are sand-sized grains (less than 2mm in diameter) consisting of one or more layers of calcite or aragonite around a central quartz grain or carbonate mineral fragment. These likely form by direct precipitation of calcium carbonate onto the ooid. Pisoliths are similar to ooids, but they are larger than 2 mm in diameter and tend to be more irregular in shape. Limestone composed mostly of ooids is called an oolite or sometimes an oolitic limestone. Ooids form in high-energy environments, such as the Bahama platform, and oolites typically show crossbedding and other features associated with deposition in strong currents. [20] [21]

Lime (material) - Wikipedia

Lime throughout history | Lhoist - Minerals and lime producer". Lhoist.com . Retrieved 10 March 2022. Skeletal grains have a composition reflecting the organisms that produced them and the environment in which they were produced. [18] Low-magnesium calcite skeletal grains are typical of articulate brachiopods, planktonic (free-floating) foraminifera, and coccoliths. High-magnesium calcite skeletal grains are typical of benthic (bottom-dwelling) foraminifera, echinoderms, and coralline algae. Aragonite skeletal grains are typical of molluscs, calcareous green algae, stromatoporoids, corals, and tube worms. The skeletal grains also reflect specific geological periods and environments. For example, coral grains are more common in high-energy environments (characterized by strong currents and turbulence) while bryozoan grains are more common in low-energy environments (characterized by quiet water). [19] Near-surface water of the earth's oceans are oversaturated with CaCO 3 by a factor of more than six. [43] The failure of CaCO 3 to rapidly precipitate out of these waters is likely due to interference by dissolved magnesium ions with nucleation of calcite crystals, the necessary first step in precipitation. Precipitation of aragonite may be suppressed by the presence of naturally occurring organic phosphates in the water. Although ooids likely form through purely inorganic processes, the bulk of CaCO 3 precipitation in the oceans is the result of biological activity. [44] Much of this takes place on carbonate platforms. Limestone is a substitute for lime in many applications, which include agriculture, fluxing, and sulfur removal. Limestone, which contains less reactive material, is slower to react and may have other disadvantages compared with lime, depending on the application; however, limestone is considerably less expensive than lime. Calcined gypsum is an alternative material in industrial plasters and mortars. Cement, cement kiln dust, fly ash, and lime kiln dust are potential substitutes for some construction uses of lime. Magnesium hydroxide is a substitute for lime in pH control, and magnesium oxide is a substitute for dolomitic lime as a flux in steelmaking. [28] Safety [ edit ]Chemical or power production: Solid sprays or slurries of calcium oxide can be used to remove sulfur dioxide from exhaust streams in a process called flue-gas desulfurization. a b Haynes, William M., ed. (2011). CRC Handbook of Chemistry and Physics (92nded.). Boca Raton, FL: CRC Press. p.4.55. ISBN 1-4398-5511-0. Connelly, Ashley Nicole (May 2012) Analysis and Interpretation of Neolithic Near Eastern Mortuary Rituals from a Community-Based Perspective. Baylor University Thesis, Texas