Minerals combined techniques

One example of the ability of this combined technique to analyze complex mixtures is provided by the use of GC-MS for a sample of mineral oil with over 50 components. Accurate identification of peaks from amounts of solutes ranging from 5 ng to 200 ng was possible. The pyrolysis of polymers, followed by separation by gas chromatography and identification by mass spectrometry (Py-GC-MS) extends the combination to include three distinct techniques. 

Two examples of surface modification of minerals will be discussed in order to illustrate the merits of a combined-technique approach. The breadth of the subject constrains the discussion to that dealing with strategies for gathering information and for choosing the most relevant surface analytical techniques. 

Hudson-Edwards, K. a., Macklin, M. G., Curtis, C. D. Vaughan, D. J. 1995. Characterisation of Pb- Zn- Cd- and Cu-bearing phases in river sediments by combined geochemical and miner-alogical techniques. In Contaminated Soils. Proceedings of the Third International Conference on the Biogeochenmtry of Trace Elements, Paris. 

Applications to coal, shale, minerals heavy hydrocarbons Combined Techniques... 

Silicate scales are among the most heat transfer-resisting of all scales. They are particularly adherent, requiring special and expensive techniques for their removal. In addition, silica forms particularly elaborate glassy scales in combination with a wide range of other minerals. Some of these scales are described here ... 

A combination of SIPS with the stabilising and synthesis-favouring properties of clay minerals was studied by Rode et al. (1999) in experiments involving dry/wet cycles. The simultaneous use of both SIPS and clay minerals as catalytically active surfaces led to peptides up to and including the hexamer (Gly)6. The question as to whether this technique fulfils prebiotic conditions can (within certain limitations) be answered positively, since periodic evaporation phases in limited areas (lagoons, ponds) are conceivable. The container material could have consisted of clay minerals. Further progress in the area of peptide synthesis under conditions which could have been present on the primeval Earth can be expected. 

WVGES has not had analytical laboratory facilities since the 1970 s so contract geochemical analyses are a necessity. After considering a variety of sources for analytical work including both university and government laboratories, we decided to use a commercial lab, located in Ontario, which specializes in analyses for the mineral exploration industry (they have since expanded into the environmental field as well). For the sake of consistency, each sample is analyzed using the same set of techniques, a combination of Instrumental Neutron Activation Analysis (INAA) and Selective Extraction-Ignition Coupled Plasma spectroscopy that yield results for 49 elements - Au, Ag, As, Ba, Br, Ca, Co, Cr, Cs, Fe, Hf, Hg, Ir, Mo, Na, Ni, Rb, Sb, Sc, Se, Sn, Sr, Ta, Th, U, W, Zn, La, Ce, Nd, Sm, Eu, Tb, Yb, Lu, Cu, Pb, Mn, Cd,... 

Since then this method has been used to solve numerous other complex crystal structures [6-13]. Because solving a stmcture from a single projection requires a short (3 to 5 A) crystal axis, the method was later extended to combine the information from several orientations which allows also to uncover stmctures with pronounced overlap of the atom columns in projection. This technique was applied in 1990 to solve the 3D stmcture of the mineral staurolithe HFe2Al9Si404 [14, 15] and more recently to determine the stmcture of the huge quasicrystal approximant v-AlCrFe [16] which contains 129 atoms per as5mimetric unit. How CIP works to solve a crystal stmcture from projected data is shown in figure 10 (for further details see [17]). 

Abstract Mobile Au in soil has been postulated for many years. It has been used by the mineral exploration industry in areas of transported overburden as a vector towards buried deposits. Until now, the nature of this mobile Au has not been known or investigated. Soil samples from a colluvial area above the Bounty Deposit (Yilgarn Craton, Western Australia) investigated by analytical techniques including laser ablation inductively coupled mass spectrometry (LA-ICP-MS) and synchrotron x-ray fluorescence (SXRF) combined with X-ray absorption spectrometry (XAS) have allowed us to map the invisible Au in these soils and suggests that at least some of it occurs in an ionic form. 

In any practical application in the mineralogy field the main task is composition analyses. There is no single detection technique that can by itself provide a 100% probability of different minerals detection combined with a low false alarm rate. We suggest the system approach, which combines different laser-based technologies having orthogonal detection and identification capabilities. In such a way the strength of one technique may compensate for the weaknesses of the others, and the vulnerability of one detection device could be compensated for by another detection device. Clever combination of the detection techniques may achieve detection probabilities and false alarm rates that are more acceptable than those of systems based on one method only. 

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