Mineralogical phases

Although sequential fractionation procedures generally do not allow assessing the precise association of elements with each soil mineralogical phase, they can provide operationally defined phase associations and may be a powerful tool for the identification of some of the main binding sites, allowing to assess the potential for remobilisation and bioavailability of arsenic in polluted soils (Wenzel et al. 2001 Martin et al. 2007a). 

The country-wide dataset of stream sediment analyses in Austria consists of 36,136 samples analyzed for 34 chemical elements (Fig. 1), (Thalmann et al. 1989). Complemented by local surveys of hydrochemistry, whole rock geochemistry, soil chemistry and mineralogical phase analyses, these data are used to derive natural background levels of different rock units, investigate chemical fluxes between soil, rock and groundwater, and evaluate the emission risks of historical mine waste. 

However, factor analysis cannot always distinguish between naturally elevated heavy metal concentrations and anthropogenic pollution. In specific areas, detailed mineralogical phase analysis is used to make this distinction and to determine the origin and transport distance of industrial particles in the environment (Neinavaie et al. 2000). 

Spectral parameters of the structured green luminescence (Fig. 4.4d) are absolutely similar to those of luminescence in fluorite after thermal treatment (Tarashchan 1978). Principally, during the calcination of the sedimentary phosphates new mineralogical phases, including fluorite, may be formed. Taking these data into accoimt, it is possible to conclude that after thermal treatment uranium is concentrated in the fluorite lattice in the form of... 

Various workers have questioned the ability of sequential extraction to provide accurate information on the mineralogical phases with which trace elements are associated in soil or sediments (e.g. Nirel and Morel, 1990). Problems, including non-selectivity of reagents and readsorption of analytes following release, are frequently reported. Hence, nowadays, most environmental analytical chemists accept that sequential extraction should be considered an operational form of speciation, in which the fractions isolated are defined purely by the sequence of reagents used, and not as a means to determine information on the specific mineralogical phases to which trace elements are bound. Modern sequential extraction procedures label the fractions obtained in terms of the type of chemical reaction used to isolate them, in order to emphasise this, e.g. reducible or oxidisable species. Unfortunately, this distinction is not always made clear in the wider environmental literature. 

Considerable interest centres on the Mantle constituting, as it does, more than half of the Earth by volume and by weight. Attention has been focussed on several problems, including the chemical composition, mineralogy, phase transitions and element partitioning in the Mantle, and the geophysical properties of seismicity, heat transfer by radiation, electrical conductivity and magnetism in the Earth. Many of these properties of the Earth s interior are influenced by the electronic structures of transition metal ions in Mantle minerals at elevated temperatures and pressures. Such effects are amenable to interpretation by crystal field theory based on optical spectral data for minerals measured at elevated temperatures and pressures. 

The mineralogical phase composition of the sample SW [86] (in wt %) is 90% 5% clinoptilolite and 10% 5% others, which include montmorillonite (2-10 wt %), quartz (1-5 wt %), calcite (1-6 wt %), feldspars (0-1 wt %), magnetite (0-1 wt %), and volcanic glass (3-6 wt %). Employing this sample and a pure clinoptilolite, whose TCEC fluctuates between 2.0-2.2 mequiv/g depending on the Si/Al relation of the clinoptilolite monocrystal, it is possible to indirectly evaluate the total cation-exchange capacity of the sample SW as follows ... 

The mineralogical phases formed by heating the clay-carbonate mixtures are summarized in Tables I and II. Solid-state chemical reactions at temperatures below fusion are rather common. 

Table 15-1 Ranges of Chemical Composition and Mineralogical Phases Present in Acid Brick (Red Shale and Fireclay)...

The results of practical tests with glasses and slags indicate that with porous refractories melt infiltration takes place which may change the mineralogical (phase) composition in zones even quite distant from the interface. If the melt penetrates to points of lower temperature, reactions with the melt may create new minerals, in the form of quite distinct zones parallel to the surface. The infiltration can be effected not only through pores but also by faster dissolution of the finer bond between the Coarser grog grains. Such a transformed surface layer may cause faster destruction. 

Thus, these data represent a mineralogical system of four main variables, changing with geological time (=depth) (Figure 2). The four main mineralogical phases are ... 

Mineralogical phases formed at different temperatures for each coal sample are summarized in Table III. The major mineral phases detected by XRD in LTA samples are quartz, pyrite, bassanite, kaolinite and plagioclase. The processes responsible for subsequent mineral transformations include oxidation, vaporization, sulfur fixation, dehydration and solid-state Interactions. The temperatures at which specific transformations occur are assigned on the basis of previous experimental work by Mitchell and Gluskoter (4) and published chemical data in the Handbook of Chemistry and Physics ( ). In addition to mineral-mineral interactions it is believed that reactions between minerals and exchangeable cations occur (2) ... 

For a better understanding of the peculiarities of SEPs, we discuss the most commonly elucidated TE fractions briefly in the following sections. Particular attention is given to the selectivity of leachants toward mineralogical phases. 

This says that the maximum number of phases to be expected in any naturally occurring system is given by the number of components in that system. This is called the Mineralogical Phase Rule, and was pointed out by Goldschmidt in 1911. In open systems,... 

To begin with, recall the Mineralogical Phase Rules, (14.60) and (14.61), which can also be written... 

Coal is a sedimentary rock composed of three categories of substances (1) organic carbonaceous matter—macerals, (2) inorganic (mainly crystalline) minerals, and (3) fluids. The latter occur in pores within and between the other two solid constituents. The fluids in coal prior to mining are mainly moisture and methane. Applied to coal, the term mineral matter is an inclusive term that refers to the mineralogical phases as well as to all other inorganic elements in coal, that is, the elements that are bonded in various ways to the organic (C, H, O, N, S) components. 

Results obtained from the present research suggest the limonitic laterite can be partially reduced by ferrous sulphate. Maximum nickel extraction was 64% at SO C, 2.73 g FeS04/ g of ore, 130 g/1 total ammonia in 10 hours. At the same conditions the cobalt and manganese extractions were only 16% and 43%, respectively. The different leaching behavior between nickel, cobalt and manganese is due to the fact that they are associated with different mineralogical phases. 

C to 5.2 at 585 °C). It is the Curie point of magnetite, which forms at 572 °C, as the DTA curve demonstrates. The values of the measured dielectric constants do not accurately correspond to the real respective constants of the mixture while being heated with microwaves, because the heating rates are much higher and a number of different mineralogical phases are formed where topically high temperatures are achieved. However, the measured constants approach the real values in parts of the sample that were heated relatively smoothly with microwaves, that is, the external surface. 

In order to determine the mineralogical phases by X-Ray Diffraction (XRD), a Philips X-Ray Diffractometer was used (model X Pert MPD) equipped with a graphite monochromator and rotational anode, operated at 40 kV and 40 mV. The data were collected via Cu-Ka radiation at a step of 0.01° and time p>er step of 2 s, in order to determine the phases present in the samples. 

Table 4. Concentrations (in Vo) of the main mineralogical phases found in the commercial cement (CEM) taken as reference in this work.

Incidentally, these zeolites have been identified from the XRD diffractograms of the samples, as presented in Table 5.38. The mineralogical phase transition in the activated residues also reveals the higher zeolitization characteristics of the OHA for synthesizing a class of zeolites with a slightly higher SAR value (2.64 > SAR > 1.60), which is in close proximity to common fly ash zeolites, Faujasite and Analcime [47]. 

---