I. Introduction
In the field of precious metal recycling and trading, adulteration methods have become increasingly sophisticated, with rhenium (Re) and tungsten (W)—two metals with densities remarkably close to that of gold—emerging as the materials of choice for counterfeiting. Rhenium has a density of 21.02 g/cm³, tungsten 19.35 g/cm³, both closely matching gold's 19.32 g/cm³. Consequently, traditional identification methods such as density measurement and touchstone testing are often inadequate to detect such fraud. Once gold products adulterated with rhenium or tungsten are mistakenly accepted, recyclers face substantial financial losses.
X-ray fluorescence spectrometry (XRF), with its non-destructive, rapid, and accurate characteristics, has become one of the most effective techniques for identifying rhenium and tungsten dopants in gold. Lanscientific's ScopeX PS6 precious metal analyzer, based on XRF technology, is capable of precisely identifying the characteristic signals of adulterant elements like rhenium and tungsten, providing a robust technical safeguard for gold recycling, refining, jewelry quality inspection, and related industries.
II. Advantages of ScopeX PS6 in Detecting Rhenium and Tungsten Adulteration in Precious Metals
1、Precise Identification of Rhenium and Tungsten Adulterant Elements
The instrument
is equipped with a high-performance detector featuring excellent energy resolution, which can precisely capture the characteristic X‑ray signals of trace elements such as rhenium and tungsten, effectively avoiding misjudgment caused by peak overlaps.
2、Non‑destructive Testing, Preserving Sample Integrity
No sample preparation or destructive sampling is required. It can directly perform in‑situ analysis on gold bars, coins, finished jewelry, etc. The sample remains intact after testing, fully preserving the trading and collection value of precious metals.
3、High Accuracy and Sensitivity
The detection accuracy can reach 0.03 % (for 9999 gold). The high‑performance detector combines high sensitivity and high count rate, effectively lowering the limit of detection for trace impurities such as rhenium and tungsten. It can also stably collect signals even from irregular samples.
4、One‑touch Operation, Rapid Results
Equipped with a built‑in smart operating system and one‑touch automated testing, results can be obtained within tens of seconds. Even non‑professionals can easily operate it, significantly improving work efficiency in recycling and quality inspection processes.
5、Simultaneous Multi‑element Detection with Intelligent Alert
It supports simultaneous detection of multiple precious metals including gold, silver, platinum, palladium, etc., automatically identifies alloy grades, and accurately determines whether adulterant elements such as rhenium, tungsten, or iridium are present, effectively guarding against risks like plated items passed off as genuine and doping fraud.
6、Safe, Reliable, and Flexibly Adaptable
Equipped with multiple safety protections including a fully enclosed metal chassis and door status detection, ensuring operator safety. The oversized sample chamber can accommodate irregular and bulky samples, covering diverse application scenarios such as recycling stores, refineries, and pawnshops.
III. Test Cases
Test Samples: Two groups of gold samples submitted by a gold recycling customer, suspected of adulteration. To verify the purity, the ScopeX PS6 precious metal analyzer was used for non‑destructive testing, focusing on screening for high‑density adulterant elements such as rhenium (Re) and tungsten (W).
Test Results:
Sample 1
Sample 2
Test Conclusion:
Sample 1 has a measured gold content of 94.902%, with impurity elements tungsten (W) at 2.637% and rhenium (Re) at 1.974%, determined to be a mildly adulterated sample.
Sample 2 has a measured gold content of 52.532%, which is below the qualification standard of ≥99.9% for pure gold; the sample contains high proportions of impurities: tungsten (W) at 1.556% and rhenium (Re) at 42.15%, determined to be a highly adulterated sample.
Both samples contain non‑gold impurity elements, indicating that the samples were deliberately adulterated.
IV. Conclusion
Rhenium and tungsten have densities remarkably close to that of gold, making them difficult to detect by traditional testing methods, and they pose a significant adulteration risk to the precious metal recycling industry. The ScopeX PS6 precious metal analyzer, based on XRF technology and equipped with a high-performance detector, can accurately identify characteristic signals of adulterant elements such as rhenium and tungsten. Its one‑touch smart operation delivers results within tens of seconds. The non‑destructive testing is adaptable to various sample forms, including gold bars, jewelry, and powders, covering diverse scenarios such as recycling stores, refineries, pawnshops, and banks. From incoming material screening to authenticity verification, Lanscientific's gold analyzers provide precise, efficient, and reliable technical capabilities, building a robust defense against rhenium and tungsten adulteration in the precious metals industry, and effectively safeguarding fair trading and business security.