Minerals calcite, CaCO

The minerals calcite, CaCOs, magnesite, MgCOs, and dolomite, CaCOs MgCOs, decompose when strongly heated to form the corresponding metal oxide(s) and carbon dioxide gas. A 1.000 g sample known to be one of the three minerals was strongly heated and 0.477 g CO2 was obtained. Which of the three minerals was it ... 

Chemical Bond Formation (Chemisorption). This is the mechanism that leads to the formation of the strongest bonds between coUectors and mineral surfaces. Chemically adsorbed reagents usuaUy form surface compounds at the active waU sites. The flotation of calcite (CaCO ) and... 

Inside the system, the acido-basic equilibria are always reached. Nevertheless, solutions can be supersaturated regarding the two mineral species, calcite (CaCOs) and calcium oxalate (CaC204). 

As in most parts of today s deep ocean the concentrations of Ca and of CO are nearly constant with water depth, profiles of CaCOs content with depth reflect mainly the increase in the solubility of the mineral calcite with pressure (see Figure 2). This increase occurs because the volume occupied by the Ca and ions... 

The most abundant carbonate minerals in mine wastes are calcite [CaCOs], dolomite [CaMg(C03)2], ankerite [Ca(Fe,Mg)(C03)2], siderite [FeC03] or mixtures thereof. The dissolution of calcite can be described as... 

Carbonate minerals. Calcite (left) and aragonite (middle) are both CaCOs, and smithsonite (right) isZnCOs. 

The regional distribution of hardness (i.e. Ca plus Mg) is shown in Fig. 4. This probably reflects the distribution of free carbonates in the sediments with areas of hard water reflecting their presence and low hardness areas reflecting their absence. The most probable carbonate minerals are calcite (CaCOs) and dolomite (CaMg(C03)2). The absence of pH and bicarbonate data from the National Hydrochemical Survey dataset means that saturation indices for these minerals could not be calculated. However, data from the three Special Study Areas (Smedley et al., 2001) suggest that there is both calcite and dolomite saturation, even slight supersaturation. 

Sedimentary calcium carbonates are formed as the shells of marine plants and animals. Biologically produced CaCOs consists primarily of two minerals aragonite and calcite. Shallow-water carbonates, primarily corals and shells of benthic algae (e.g. Halimeda) are heterogeneous in their mineralogy and chemical composition but are composed mainly of aragonite and magnesium-rich calcite (see Morse and Mackenzie (1990) for a discussion). Carbonate tests of microscopic plants and animals, most of which hve in the surface ocean (there are also benthic animals that produce carbonate shells), are primarily made of the mineral calcite, which composes the bulk of the CaCOs... 

Figure 2.5. Scanning electron micrographs of (a) hyphae of Serpula himantioides mineralized with calcite (CaCOs) and whewellite (calcium oxalate monohydrate, CaC2O4-H2O), (b) calcite precipitated in proximity to and (c) on biomass of a Doratomyces sp. (From E. P. Burford and G.M. Gadd, unpublished Burford et al., 2006.)...

Jacobs, G.K., Kerrick, D.M., and Krupka, K.M. (1981) The high- temperature heat capacity of natural calcite (CaCOs), Phys. Chem. Minerals 7, 55-59. 

Catti, M., Pavese, A., Aprd, E., and Roetti, C. (1993) Quantum- mechanical Hartree-Fock study of calcite (CaCOs) at variable pressure, and comparison with magnesite (MgCOs), Phys. Chem. Minerals 20, 104-110. 

The development of CaCOs tablet-like arrays was achieved at the air/water interface through the cooperative mineralization regulated by a polypeptide and a DHBC, namely PEO-PMAA [95]. The experimental data indicate that the role of the block copolymer is focused on the regulation of the arrangement and orientation of the CaCOs tablets. The cooperative action of a polypeptide is essential for the formation of CaCOs tablet at the air/water interface. In the absence of the polypeptide, the formation of calcite CaCOs particles in the water phase was observed. 

Biochemical or biogenic sedimentary rocks are formed from calcareous skeletons of organisms. The main constituent mineral is calcite (CaCO ). Limestone is the main rock type in this category. 

TIC in soils predominantly derives from carbonate minerals such as calcite (CaCOs) and dolomite (MgCOs). TIC will also be impacted upon by soil s... 

The most common nonphosphalic accessory minerals associated with sedimentary phosphate rocks are quaife— clays, and two carbonates dolomite (CaMg(C03)2) and calcite (CaCOs). Carbonate-cemented phosphate rocks are particularly noteworthy because of their abundance. McClellan and Gremillion [14[ estimated that there are 3 tonnes of carbonate-cemented phosphate rock for every tonne of ore that could be handled by conventional milling and flotation processes (quartz- and clay-containing phosphate rocks). 

The most important carbonate mineral is calcium carbonate, CaCOs. This substance occurs in beautiful colorless hexagonal crystals as the mineral calcite. Marble is a microcrystalline form of calcium carbonate, and limestone is a rock composed mainly of this substance. Calcium carbonate is the principal constituent also of pearls, coral, and most sea shells. It also occurs in a second crystalline form, as the orthorhombic mineral aragonite. 

The calcium carbonate, CaCOs, in an eggshell has the same crystal structure as In the mineral calcite. 

The most abundant carbonate minerals are calcite (CaCOs) and dolomite (CaMg(C03)2). Secondary minerals are anhydrite, chert, and quartz. Accessory minerals are phosphates, glauconite, ankerite, siderite, feldspars, clay minerals, pyrite, etc., depending on the environment of deposition and diage-netic history. 

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