Clay Mineral Analysis

X-Ray diffractometry is used to determine semiquantitatively the content of minerals belonging to the mica-, chlorite-, smectite- and kaolinite group in the fractions < 20 µm or < 2 µm. After ion exchange with potassium and magnesium, textured samples are prepared on ceramic plates. Identification of clay minerals is based on expansion characteristics following solvation with glycerine and dimethylsulfoxide. Additionally, the content of non-sheet silicates (quartz, feldspar, carbonates) from non-textured samples is determined. An effective smectite content can be calculated based on the grain size content < 2 µm. Active minerals are identified in the course of a frost susceptibility assessment (Frostsicherheit ON 4810) or a test for suitability as a mineral sealing layer (ON S 2074), for example.

Equipment: Philips PW 1830 (Cu-tube) © TU Graz/IAG

Reference Standard: ON B 4810; ON S 2074