Estimate of clay minerals amounts from XRD pattern modeling: The Arquant model

This work presents an XRD pattern model applied to the quantification of clay minerals in the <2 mu m fraction. The model is based on a linear combination of patterns previously simulated with specific codes. The modeling procedure is especially adapted to the oriented deposits performed from a suspension although it can also apply to the oriented pastes. The estimate of mica-like phases proportions allows to correct efficiently the illite amounts obtained. The model displays an interesting accuracy with an uncertainty of 8.6% at 59% of confidence. It is applied to the analysis of a natural sample, collected from a particular clay rock formation, related to the French nuclear waste storage project. (C) 2006 Elsevier Ltd. All rights reserved.