Recovery of dispersed clay-sized suspensions for X-ray diffraction mineralanalysis

The determination of soil engineering properties is essential for the succe ssful design of all types of construction projects. However, the testing me thods required are often time-consuming and expensive. Therefore, approxima te prediction techniques have been developed to save time and money using s impler soil tests, such as particle-size distribution, to achieve this purp ose. The existing methods for such particle identification rely purely on g rain size analysis and consider all mineral particles with an effective dia meter of less than two microns to be clays. However, soil mineralogy, geoch emistry and the differences between predicted and real values indicate that this is not entirely correct. To establish and quantify the 'true clay fra ction' for more realistic modelling of soil behaviour, a technique has ther efore been developed by which the mineral fraction can be recovered in a st ate that is suitable for X-ray diffraction analysis. The mineralogical data obtained in this manner can then be used to improve the available evaluati on parameters and thereby provide a more realistic prediction model of the soil's behaviour.