Methods for the quantitative determination of asbestos and quartz in bulk samples using X-ray diffraction

Abstract

Procedures are described for the quantitative determination of the asbestos and α-quartz contents of bulk samples by use of X-ray powder diffractometry. The method gives satisfactory results for several different types of asbestos and for mixtures of two or more different types. Problems with sample grinding and preferred-orientation effects have been largely overcome. An effective procedure has been developed for grinding samples to a suitable particle size for accurate quantitative work. This procedure works equally well for all the types of asbestos studied and the sample is intimately mixed with the internal standard, nickel (II) oxide, at the same time. A sample press has been designed that enables the same pressure to be applied to each sample when sample holders are filled for the diffractometer, giving the same degree of preferred orientation each time. Calibration lines have been calculated for chrysotile, amosite, crocidolite and anthophyllite, and results are given for mixtures containing two or more types of asbestos as well as other commonly occurring minerals.

Similar techniques are used to grind samples containing quartz and to mix them with internal standard. Work on both synthetic and real samples is described and results are compared with those obtained by use of an infrared spectroscopic method.