Applications of XRD and XRF

Bricks and Tiles

X-ray Mineral Services have been operating in the bricks and tiles industry since 2006, providing X-ray diffraction (XRD) and X-ray fluorescence (XRF) analytical and consultancy services. The major players including Wienerberger and BMI Redland (formerly The Monier Group) have benefitted from our analytical and geological expertise and experience in characterising heavy clays. With samples originating from various quarries in the UK, Europe and worldwide, we have built a vast library of data on clay materials from multiple sources. This includes routine process control samples, stockpile layers and composites, as well as fillers and blends whereby XRD is used to characterise and quantify the clay mineralogy and XRF to determine the elemental chemistry.

These analyses are imperative prior to brick and tile manufacturing to ensure consistency within the raw materials and are therefore valuable quality control tools. They also provide important information on any impurities that are inevitably present in natural raw materials, identifying iron compounds, carbonates and sulphates. Understanding the mineralogy of the raw material is critical to determine both clay and non-clay components as they inherently control the firing behaviour, colour and mechanical strength of the final product. The chemical analysis and quantification of the elemental oxides using XRF provides invaluable data and validates the mineralogical phases identified by XRD. The loss on ignition is also determined separately and can be attributed to the structurally-bound water, oxidation of sulphides, breakdown of carbonates and combustion of organic matter.

Routine analyses of stockpiles can highlight subtle variations in the mineralogical and chemical composition of the raw materials that may impact the quality and consistency of the final product. Therefore, consistent sampling can indicate any heterogeneities both within and between stockpiles and can be dealt with prior to manufacturing. These analytical processes are also invaluable tools when applied to the investigation of quarry extensions and the search for compatible as well as new resources.

Data quality is regularly checked by participation in inter-laboratory proficiency tests and competitions. Click for more details.

Question: When is a 'marl' not a marl?

Answer: When it comes from Etruria, and we are not talking about Italy here! In the latter part of the 19th century the 'productive' rocks of the British Carboniferous were the basis of explosive growth in manufacturing and contemporary geologists were struggling to make sense of the disparate mineral outcrops of different regions.

The Clays of Seiont Brickworks Quarry

Bricks were made on the southern outskirts of Caernarfon from the mid-19th century until 2008 under the name Seiont, though latterly in the hands of the Butterley Group and Hanson PLC. Unlike other small brickmakers in northwest Wales, the raw clay was not alluvial in origin, but a friable outcrop of Ordovician mudstone. That is in itself a strange feature, since the Nant Ffrancon Formation is elsewhere a very hard, low-grade metamorphic rock famous for producing some of the country's finest roofing slates.