Clay Identification and Analysis

Clay minerals are used in a wide variety of industries, including ceramics, oil drilling, mining, paints, coatings, absorbents and the metal and paper industry. These industries face a host of clay-related problems. Clays can be difficult to characterize due to their small size, variable structural composition and relative slow kinetics of formation and alteration. SGS has the industry-leading expertise in High Definition Mineralogy to provide clay identification and interpretation.

XRD (X-ray diffraction) provides rapid identification of minerals and reveals detailed information about the chemical composition and crystallographic structure of your samples. It is useful for identifying fine grained phases which are difficult to identify optically, by Scanning Electron Microscope/Energy Dispersive Spectrometer (SEM/EDS) or Quantitative Evaluation of Materials by Scanning Electron Microscopy (QEMSCAN®).

Applications

XRD is the preferred method for clay speciation, particularly swelling clays such as smectites. Clay mineralogy can provide a critical indicator of the presence of mineralization. This technology has a number of important applications for clays:

• Indication of presence of mineralization
• Identification of fine grained phases
• Understanding mineralogy textures and grain size distribution for processing activities

Clay Speciation XRD Analysis

Clay minerals identified by X-ray diffraction analysis will be reported and grouped into major (>30%), moderate (10-30%), minor (2-10%) and trace (<2%) amounts. Due to the poor crystallinity of clay minerals, the samples are separated using a centrifuge followed by a series of procedures (e.g. the addition of ethylene glycol and high temperature heating). This preparation is necessary to differentiate between clay species.

Semi-quantitative Clay Speciation XRD Analysis

Clay minerals can be reported and grouped into major, moderate, minor and trace amounts. Mineral abundances for the bulk sample (in weight %) generated by RIR (or Rietveld) XRD analysis will be reconciled with a whole rock analysis plus the analysis of any other major elements contained in the sample and reported. Whole rock analysis by X-ray fluorescence spectroscopy includes SiO₂, Al₂O₃, Na₂O, K₂O, CaO, MgO, Fe₂O₃, Cr₂O₃, MnO, TiO₂, P₂O₅, V₂O₅ and LOI.

SGS is the industry leader in High Definition Mineralogy for the global minerals industry and other market sectors that need detailed material, product or residue characterizations. For quantitative mineralogical analysis and determination of clay technological properties, trust SGS.