Summary for cyanide gold solution analysis Discussion
cyanide gold solution analysis by xrf is the core issue in this thread: Robert Belter says a new XRF is giving results far below actual value for cyanide gold baths, while an older unit had tracked gravimetric checks much better. Bob Forrest first suggests the older instrument may have drifted and recommends getting fresh standards from the supplier, noting that if the standards are still valid the instrument may be faulty. Robert clarifies that he makes his own standards and that the new instrument, not the old one, is the problem. Pancho Macalincag advises going back to the supplier or manufacturer for sample-specific guidance, and cautions that synthetic calibration standards can limit absolute accuracy. He also notes that a 40% low result is significant and could point to errors in standard preparation. The discussion does not resolve the exact cause, but points toward instrument applicability, calibration, and standard preparation as the main checks.
Q. I am currently working for a company that performs Au analysis of their cyanide-based baths (type 1 and 3) by XRF. Although this instrument is over ten years old, it appears to furnish results that are well within the degree of accuracy required for Au add determination, etc… The problem arises from a new XRF that was recently purchased in order to take advantage of the advances in software, multiple layer thickness determination and real-time emission analysis of unknown metallic samples. I have not been able to obtain usable results whatsoever when analyzing said cyanide gold solutions. My cyanide gold salts in DI water standards are not effective on this new instrument. If I didn’t know better, I would suspect matrix interference/ signal supression, but why? And why not on the older XRF? Different X-ray lamp energies? Any input would be of help. I can easily say more, but I’ll throw this out there for the time being!
Robert Belter
– San Diego, California, USA
2003
A. I have used this instrument. It operates on radio active isotopes. The older unit may have been losing its energy. The newer unit is full. If your standards do not work, contact the company and ask them for a set of new standards. This may be the problem. If their standards are still out, the instrument is faulty.
Good luck. It is a nice instrument and should work for you. First impression is it is out of spec.
Bob Forrest
– Maine
2003
Q. I don’t think you quite understand. I make my own standards and it’s the NEW instrument that’s giving me grief. The same calibration run on the two XRF’s give me two totally different results. Outside gravimetric analysis shows that our old XRF is close to the mark whereas the new instrument will give me 60% of actual value, at best.
Robert Belter [returning]
– El Cajon, California, USA
2003
A. I think you should go back to the supplier or manufacturer of the new XRF. They may be able to give you specific recommendation on its use or applicability to the specific type of sample at hand. Just like most analytical instruments, absolute accuracy is not possible, if they are dependent on synthetic calibrations standards. Based on what you said you are getting, 40% less than the actual value is quite significant and could indicate errors in standard preparation.
PANCHO MACALINCAG
– Auckland, New Zealand
February 23, 2011