Bulk Powder Analysis (BPA) of whole rock samples is suitable for quick mineral identification. Samples can be ground in an agate dish (XBP) or micronized by McCrone Mill (MBP) to obtain the desired particle size distribution (< 10 μm).
Recommendation
- 5 g of a dry powdered sample of < 250 μm size fraction is preferred. If samples are delivered wet and bulky, additional preparation steps (drying, grinding, or sieving) prolong the analysis.
- If the sample is already finely ground upon receipt, it is gently disintegrated in an agate dish before installation in the sample tray (XBP rate).
- The average turnaround time for BPA analysis is two weeks per 10 samples.
Methodology
XBP: 3-5 g of the sample (< 250 μm) is ground in an agate dish before installation in the sample tray. Step-scanned data is collected from 5° to 70° 2θ with a fixed rate of 1° per minute with a step size of 0.02°2θ.
MBP: 3-5 g of the sample (< 250 μm) is mixed with 10 mL of propylene alcohol and then micronized for 10 minutes in McCrone Mill. The sample suspension is rinsed from the grinding jar, centrifuged, decanted, and dried in an oven at 70 °C overnight. Once in powdered form, the sample is packed into a sample tray and analyzed by XRD. Step-scanned data is collected from 5° to 70° 2θ with a fixed rate of 1° per minute with a step size of 0.02°2θ.
Results
- The XRD (XBP, MBP) analysis provides qualitative (mineral phase identification) based on the location and intensity of peaks of the 2θ scale compared with the PDF2 database using Materials Data Inc. (MDI) known as JADE.
- The Quantitative XRD analysis is based on the Rietveld refinement and the semi-quantitative analysis.