Specific minerals

Section XI.2.2 includes a discussion of some thermodynamic properties of thorite, including a discussion of the thorite-huttonite phase transformation. 

This result indicates that Th-brannerite is entropy-stabilised and may be stable at high temperature only. 

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Regularly interstratified (1 1) chlorite and vermiculite has been attributed to the mineral corrensite [12173-14-7] (141). Chlorite mixed layers have been documented with talc, vermicuhte, smectite, iUite, biotite, kaolinite, serpentine, and muscovite. The mixed-layer mineral is named after the components, eg, talc—chlorite. The eadier Hterature, however, has reference to specific minerals such as kulkeite [77113-95-2] (talc—chlorite and tosudite... 

NOTE In practice, higher quality, pre-boiler water treatment generally means the use ofFW with significantly lower levels of dissolved solids than typically employed in lower rated boilers. Additionally, it implies the reduction of certain specific minerals, ions, and noncondensable gases to meet very low, or extremely low, concentration specifications. 

The number of oxide type minerals is quite large. Rostov (1956) has identified 160 specific minerals, grouped them into classes (chrysoberyl, spinel, corundum, periclase, etc.), and proposed a classification system. Only a few examples will be discussed here. 

It is important to distinguish clearly in this scenario between the general solidification of the Earth s crust, which had the effect of freezing in variations in the U/Pb and Th/Pb ratios, and the specific mineralization event which created the galena (lead sulfide, PbS) deposits, which removed the lead from the uranium and thorium, and effectively therefore froze the isotopic composition of the lead in the galena at the values representative of the time of mineralization. 

Also the aim of the wastewater treatment process will change strongly. Preference will be given to treatment technologies which have not only the potential to purify water but which have also the potential to produce valuable products from pollutants (such as biogas) or to recover valuable components from the wastewater, such as nutrients (phosphate and ammonia), heavy metals or specific minerals. Also the specific process conditions, such as use of chemicals and energy, and the wastes which are produced in a wastewater treatment step are more and more considered from an environmental point of view. Finally it can be expected that the compactness of the treatment process, related tot the required residence time of the wastewater in the system, is becoming more and more important. The... 

To the extent that the surfaces of the kaolinite layers resemble the surfaces of other silicate minerals, the structure of the adsorbed hole and associated water can serve as a useful model. To determine the applicability of our model to a specific mineral, it will be necessary to know in some detail the structure of the external surfaces of that mineral. 

Discussion and Conclusion The chemical composition of iron oxides is useful to discriminate a range of mineral deposit types. Discriminant diagrams can be used to identify potential for specific mineral deposit types to occur in an area that has been glacially eroded using till. In this study, a small subset of the ferromagnetic fraction (50 grains, 0.5-1.0 mm size fraction) of a till has been shown to adequately display the compositional... 

In this research, the purpose of the cluster analysis Is to obtain groupings of samples with compositions similar to specific minerals or with only a subset of all the minerals In the bulk sample. This Is necessary In most geological samples In order to... 

Despite considerable effort to understand the chemical nature of the organic and inorganic portions of coal, and substantial advances in instrumentation and methodologies, much of coal s chemical nature remains intractable. This paper reviews methods and their limitations for the determination of specific minerals in coal, and presents results of efforts at Consolidation Coal Company to develop FTIR methods for routine coal mineralogy. 

In geothermometry, geologists use information in a rock to infer the temperature history of a rock. For example, if a rock contains sillimanite, it can be inferred that it must have experienced temperatures above the triple point of sillimanite, kyanite, and andalusite. If a rock contains sanidine, it must have experienced high temperatures and have cooled down rapidly. The appearance of specific minerals only gives a limit on the temperature. To infer the specific temperature, homogeneous or heterogeneous reactions with continuous variation of K on temperature are required. 

Furthermore, specific mineral matrices for use in conditioning separated radio nuclides are also elaborated and studied on the basis of mineral structures, known in nature for their selective-insertion capabihties with respect to certain radio nuclides and their stabihty over time. Among those phases, hollandite, zirconoUte, apatite and monazite are particularly studied. 

Although it is beyond the scope of this book, we will note that trace element partitioning can be modeled if partitioning coefficients between a magma and specific minerals have been measured. These models (described numerically in most geochemistry texts) provide quantitative constraints on melting or crystallization processes. 

Electron microprobes can be used in spot mode to measure the chemical compositions of individual minerals. Mineral grains with diameters down to a few microns are routinely measured. The chemical composition of the sample is determined by comparing the measured X-ray intensities with those from standards of known composition. Sample counts must be corrected for matrix effects (absorption and fluorescence). The spatial resolution of the electron microprobe is governed by the interaction volume between the electron beam and the sample (Fig. A.l). An electron probe can also be operated in scanning mode to make X-ray maps of a sample. You will often see false-color images of a sample where three elements are plotted in different colors. Such maps allow rapid identification of specific minerals. EMP analysis has become the standard tool for characterizing the minerals in meteorites and lunar samples. 

Allevardite is one specific mineral name and/or mineral group which should be more closely defined. Essentially this is an ordered, mixed layered mineral, that is one with regularly alternating non-expanding and expandable layers. The major character of these minerals is the... 

It is obvious then that A1 is not synonymous with Fe in sedimentary mica-like minerals. The increasing influence of trivalent iron in a sedimentary system will obviously provoke the crystallization of a specific mineral series which is not contiguous with illite and which would not be present otherwise. The development of glauconite in sediments should be due to specific local conditions which permit the chemical evolution of an initial montmorillonite material to celadonite mica-like phase. In fact previous observations have consistently led to this conclusion as to the origin of glauconite in sediments and sedimentary rocks. 

Specific mineral identification is not important beyond the designation... 

Sepiolite and palygorskite have a rather special composition and seem to be related to specific mineral parageneses. They appear to be stably associated with montmorillonite, corrensite, serpentine, chert, sulfates, carbonates and various salts. They are found in deposits typified by processes of chemical precipitation or solution-solid equilibria (Millot, 1964) and are therefore rarely associated in sediments with large quantities of detrital minerals. Their chemical environment of formation is in all evidence impoverished in alumina and divalent iron. Their frequent association with evaporites, carbonates and cherts indicate that they came from solutions with high chlorinity. 

F maximum—is that in geological situations, the persistence of a specific well-defined set of physical conditions during mineral crystallization should be rare since pressure and temperature vary with time and thus their influence upon the crystallization of a specific mineral assemblage cannot be represented by a set of fixed conditions. Certainly some mineral assemblages are formed when P maximum but they are probably rare. 

It has been postulated that proteoglycans play an important role on mineral growth253,2S5, s04, s05). Also, a specifically mineral-generative role for these compounds has been suggested506-508. Evidence has been found for calcium storage in... 

These examples illustrate that biomolecules may act as catalysts in soils to alter the structure of organic contaminants. The exact nature of the reaction may be modified by interaction of the biocatalyst with soil colloids. It is also possible that the catalytic reaction requires a specific mineral-biomolecule combination. Mortland (1984) demonstrated that py ridoxal-5 -phosphate (PLP) catalyzes glutamic acid deamination at 20 °C in the presence of copper-substituted smectite. The proposed pathway for deamination involved formation ofa Schiff base between PLP and glutamic acid, followed by complexation with Cu2+ on the clay surface. Substituted Cu2+ stabilized the Schiff base by chelation of the carboxylate, imine nitrogen, and the phenolic oxygen. In this case, catalysis required combination of the biomolecule with a specific metal-substituted clay. 

Coal from Dorenaz, Valais, Switzerland. This anthracitic coal of Carboniferous age shows interesting peculiarities (Figure 5). In contrast to the former case, the a-activity is arranged along lines parallel to the bedding, either as stars or as bands (Figure 5d, e). In the polished sections one observes elliptical halos without specific mineral inclusions or bands of very fine black particles. The anisotropy effects are very marked as different kinds of crosses or vivid bands (Figure 5a, b). 

The procedure used to define an equilibrium model is to (1) define all the variables and (2) define independent equilibria as a function of phase equilibria. The variables are defined as the chemical parameters typically measured in water chemistry. For the major constituents and some of the more important minor constituents, these are calcium, magnesium, sodium, potassium, silica, sulfate, chloride, and phosphate concentrations as well as alkalinity (usually carbonate alkalinity) and pH. To this list we would also add temperature and pressure. The phase equilibria are defined by compiling well-known equilibria between gas-liquid phases and solid-liquid equilibria for the solids commonly found forming in nature in sedimentary rocks. Within this framework, one can construct different equilibrium models depending upon the mineral chosen actual data concerning the formation of specific minerals therefore must be ascertained to specify a particular model as valid. 

Natural colours are due to the chemicals present in them. Pigments or colours are obtained from specific minerals. Colours of the gems are also due to the chemicals present in them. Some minerals are ground into fine powder and used in the manufacture of cosmetics, paints and inks. 

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