Impurities dolomite

Olivine crystallizes from magmas that are rich in magnesia and low in silica and which form such rocks as gabbros, norites, peridotites and basalts. The metamorphism of impure dolomites or other sediments in which the magnesia content is high and silica low seems to produce olivine. 

Lassey KR, Blattner P (1988) Kinetically controlled oxygen isotope exchange between fluid and rock in one-dimensional advective flow. Geochim Cosmochim Acta 52 2169-2175 Latlanzi P, Rye DM, Rice J.M (1980) Behavior of C and O in carbonates during contact metamorphism at Marysville, Montana Implications for isotope systematics in impure dolomitic limestones. Am J Sci 280 890-906... 

A relatively "hard-to-burn" feed from the western U.S., with a very impure dolomitic limestone, has 6.7% >125 pm and an acetic-acid insoluble residue of 9.5% >45 pm, the latter comprised of quartz, feldspar, medium to finely crystalline igneous and metamorphic rock fragments, and an abundance of ferro-magnesian minerals (mainly amphiboles and pyroxenes). = 1.6% and = 4.5%. Belite nests (many with tightly packed crystals), solitary belite, and periclase are abundant in this fine- to medium-crystalline clinker. Nevertheless, a high-compressive strength mortar (44.8 to 48.3 MPa) is made, mainly because of the small alite size and the well-scattered solitary belite. 

The term lime also has a broad coimotation and frequently is used in referring to limestone. According to precise definition, lime can only be a burned form quicklime, hydrated lime, or hydraiflic lime. These products are oxides or hydroxides of calcium and magnesium, except hydraiflic types in which the CaO and MgO are chemically combined with impurities. The oxide is converted to a hydroxide by slaking, an exothermic reaction in which the water combines chemically with the lime. These reversible reactions for both high calcium and dolomitic types are Quicklime... 

Many lime plants are able to reduce the impurities in their lime product by careful screening and selecting of stone for burning. Because 9 kg of limestone produce only 5 kg of quicklime, the percentage of impurities in a quicklime is nearly double that in the original stone. Analyses of typical samples of high calcium, magnesian, and dolomitic limestones found in the United States are Hsted in Table 1. 

Over the past decades, advances have been made that reduce environmental impacts of coal burning in large plants. Some arc standard and others experimental. Limestone (mainly calcium carbonate) scrubber smokestacks react with the emitted sulfates from the combustion and contain the chemical products, thereby reducing the release of SO., into the atmosphere by a large factor (of ten or more). Pulverization of coal can also allow for the mechanical separation of some sulfur impurities, notably those in the form of pyrites, prior to combustion. Currently deployed—with more advanced versions in the development stage—are various t yies of fluidized bed reactors, which use coal fuel in a pulverized form, mixed with pulverized limestone or dolomite in a high temperature furnace. This technique reduces sulfate release considerably. There are... 

Thermal analysis has been widely and usefully applied in the solution of technical problems concerned with the commercial exploitation of natural dolomite including, for example, the composition of material in different deposits, the influence of impurities on calcination temperatures, etc. This approach is not, however, suitable for the reliable determination of kinetic parameters for a reversible reaction (Chap. 3, Sect. 6). 

Marble. The word marble is used as the common name for two types of monomineral rocks one derived from limestone and therefore composed of calcium carbonate, the other derived from dolomite and composed of calcium magnesium carbonate. Extremely high pressures and heat during past geological times modified the structure of both limestone and dolomite, compacting them into a characteristic crystal structure. Most marble is white however, minor and trace amounts of metallic impurities cause the formation of stains in a variety of colors, hues, and patterns, or of colored marble. 

Basic Open Hearth A version of the Open Hearth process for steelmaking in which the hearth is made from calcined dolomite (calcium and magnesium oxides). The sulfur and phosphorus impurities in the raw materials are converted to basic slag, which is separated from the molten steel. First operated in 1882 at Alexandrovsky, near St. Petersburg, Russia, and at Le Creusot, France. It was the major steelmaking process in the world in the first half of the 20th century. See Thomas. 

The Arnold Pit is on the steeply dipping, overturned limb of the Sylvia Lake Syncline, the structural hanging wall is the stratigraphic footwall. Commercial talc occurs in Unit 13 near the contact with Unit 14 of the Upper Marble from the metamorphism or impure evaporative dolomite. The upper section of Unit 13 grades from tremolite-rich talc ore into a pure talc schist up section. Unit 12 is a white massive doiomitic marble with convolute bands of grey and orange to... 

Zoisite occurs in crystalline schists which are products of regional metamorphism of basic igneous rocks rich in plagioclase, the calcium-nch feldspar also in argillaceous calcareous sandstones, thulite from quartz veins, pegmatites, and metamorphosed impure limestones and dolomites. 

Table II shows the quantitative XPS results for all of the samples studied. Not unexpectedly, the dolomite substrate showed the least amount of carbon of all the samples. Two samples, Sample 2 (the shiny coating with little substrate) and Sample 3, had high levels of nitrogen, significantly more than would be expected for a humic or fiilvic acid. The atomic compositions of the other coating samples compared well with experimental and theoretical C, N, and O contents for humic acids. The standard humic acid from Alfa Aesar contained a significant amount of K as an impurity. The origin of this particular humic acid is not known, even to Alfa Aesar. Traces of Ca, Cl, Fe, and Si are likely from dissolved salts that are deposited at the cave surface.

Several studies of the effects of heating on pure clays have been reported in archaeological literature, but very little systematic work has been done on the effects of admixed mineral impurities upon the clays that constitute ceramic paste. The purpose of this chapter is to study the controlled firing of four measured mixtures of the clays, kaolinite and montmorillonite, with the common carbonates, calcite and dolomite. 

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