X-ray fluorescence (XRF) is a non-destructive analytical technique used to determine the chemical composition of materials. Portable XRF technology has been around since the late 1960s, and each generation has offered improved size, speed, performance, and ease of use. Today’s portable and handheld XRF analyzers have become the standard for instant elemental analysis in a wide range of applications in any field environment, yet misperceptions persist about the capabilities of these instruments. In this post, we’ll examine some of the most common myths about portable XRF analyzers.
Myth #1: XRF isn’t effective for locating precious metals.
In reality, precious metals can be detected directly by portable XRF analyzers in most instances, such as in ore grade control and exploration of rich zones. In cases where there are very low concentrations of precious metals, portable XRF analyzers are excellent at identifying pathfinder elements, which can be used to locate precious metal deposits because pathfinder elements are present at higher concentrations than the target elements, and they originate from the same source or were deposited at the same time and place. See an example of how it’s possible to successfully locate zones of high concentrations of precious metals (platinum, palladium, and gold, in this case) by using portable XRF on pathfinder elements.
Myth #2: XRF isn’t a useful technology for oil & gas exploration.
Oil and gas deposits are difficult to find and expensive to drill, so geologists need efficient, fast processes to figure out where these deposits are and evaluate their potential. Portable XRF technology is improving upstream oil and gas exploration and production by providing rapid sample analysis of drill cuttings, outcrops, piston-core sediment, and oil and gas cores. This information can be used for identifying formations and determining the mineral composition of rock and whether or not it has properties favorable to oil and gas production. New XRF analyzers are able to detect light elements to more accurately locate oil-bearing strata, improve mud-logging, and support geo-steering. And because XRF analyzers are used in the field, in real time, they provide a timely and cost-effective alternative to off-site laboratories. Read an application note about the use of XRF technology to analyze a variety of sample types common in the upstream E&P industry.
Myth #3: XRF cannot be used to determine lithology.
Another important aspect of oil and gas exploration that can be accomplished with portable XRF analysis is identifying rock type, or lithology. Lithology is accomplished with time consuming, off-site laboratory methods such as optical microscopy. Elemental composition and ratios can be used to determine lithology. XRF not only identifies elemental composition, but also the subtle changes in geochemistry of reservoir rocks, and can monitor the gradual transition from one rock type to another. Read a case study summarizing the results of field-portable XRF analysis conducted on 221 samples collected from an oil and gas drill site in Southeast Asia.
Myth #4: XRF is inferior to laboratory analysis.
With adequate sample preparation, portable XRF analyzers yield results comparable to laboratory results but generate this high-quality analytical data within minutes, rather than days or weeks. Portable XRF instruments are designed to simply “point-and-shoot.” While this method provides very accurate results similar to those from prepared samples, the results may not be repeatable because a different section of the sample will be analyzed in each assay. When sample heterogeneity is an issue, portable XRF combined with sample preparation is the answer. The uniform surface and homogeneous nature of a prepared sample can improve the detection limits and the accuracy of field portable XRF analyzers. Sample preparation takes only a few minutes, the results are repeatable, and XRF analysis is nondestructive, allowing a portion of the prepared sample to be sent to the lab for direct comparison. Review results of a study on how portable XRF analysis may be enhanced with sample preparation, including the correlation curves, repeatability data, methodology, and comments.
Myth #5: You have to be a scientist to use XRF.
Today’s portable and handheld XRF analyzers are specifically designed to be operated and interpreted by the non-scientist. Minimal training is required to operate a portable XRF analyzer. The instruments are usually pre-calibrated and display the exact percentages of elements present in a sample. Many analyzers are outfitted with GPS/GIS capability for instant geochemical mapping in the field. Finally, some believe that XRF analyzers are all the same. In fact there are a multitude of instruments designed and calibrated for specific applications within mining, as well as for other industries including metals analysis, consumer products screening, and environmental analysis.
View a comparison of popular XRF instruments to see which analyzer might be right for you.