Standardless quantitative mineralogical analysis of rocks

Abstract

The main difficulty in the quantitative mineral analysis of rocks is connected with the variable nature of the mineral species. In the present paper a combined method (and a corresponding computer program) is proposed, which practically overcomes this difficulty. This method is based on linear equations, which are a combination of the chemical mass-balance equations with those of the quantitative X-ray diffractometry, and can perform (completely or partly) both the quantification and the chemical characterization of the minerals on several rock samples simultaneously, demanding only easily accessible initial information, such as: (i) major element (oxide) compositions for the samples; (ii) qualitative mineral composition of the samples; (iii) X-ray intensities for one or few nonoverlapped reflections of the crystalline minerals (not necessarily of all): (iv) some characteristic data for the phases (i.e., chemical composition data), if these are accurately known. Where it is possible the minerals may be expressed via end members. The samples may contain amorphous phases and/or phases without X-ray data. From the general case some very simple partial cases are derived, demanding less initial information. This method has the following advantages over the previous ones of similar philosophy: (i) drastic reduction of the number of required samples; (ii) sufficiency of equations for any analytical problem; (iii) possibility of performing partial analysis when a complete one is impossible; (iv) possibility of using the same end member in more than one solid solution. Analysis examples are given.

Engineering Properties and Shrinkage Limit of Swelling Soils in Greece

“…The mineralogical composition in clay samples (Table 2), was determined by X-ray diffraction analyses, and the quantitative analyses was obtained by the method described by Bayliss [9] and Zangalis [10]. From the quantitative X-ray analysis the following minerals were found to be present and the results from three locations are shown on Table 2.…”

Quantitative Phase Analysis of Mixtures of Three Components using Rietveld and Rius Standardless Methods. Comparative Results

“…(a) Standardless analysis methods based on X-ray data only (MOORE, 1965;SALYN & DRITS, 1972;ZEVIN, 1977;FIALA, 1980;STARKS et al, 1984;FANG and ZEVIN, 1985;RIUS et al 1987;BISH and POST, 1993;ESTEVE et al, 1997b;ZANGALIS, 1998). Below are presented two different cases of these methods, described for quantitative X-ray analysis.…”

“…Below are presented two different cases of these methods, described for quantitative X-ray analysis. (b) Standardless methods based on chemical and X-ray data simultaneously (ZANGALIS, 1991(ZANGALIS, , 1998STARKS et al, 1984;WANG & PU, 1991). Here the number of phases is considered to be given and one or more nonoverlapping reflections correspond to each phase.…”