The handheld X-ray Fluorescence (XRF) analyzers from Evident offer high-performance, real-time data for faster elemental analysis of not just metallic samples like Gold (Au) pin samples but also precipitates, mill feeds, and environmental samples in gold mines.
Laboratory personnel use XRF analyzers as a screening tool and in certain instances as an alternative for fire assay techniques. Progresses in signal processing and XRF detector technology have led to optimization of the detection limits and precision, a considerable reduction in analysis test times, and an increase in the number of elements that can be measured.
These analyzers can offer a quick return on investment in a gold mine site laboratory.
Handheld XRF vs Fire Assay—Au
Advantages of Handheld XRF
- Reduction in analytical turnaround time from several hours to several minutes
- Considerable cost savings related to reagents consumed and decrease in lab technician time
- Enhanced metallurgical recovery of gold in the mill using handheld XRF for everyday stockpile/feed analysis of Silica
- Improvements in industrial hygiene, laboratory safety, and environmental performance
Handheld XRF vs Fire Assay—Au
Return on Investment
The Evident Handheld XRF analyzers have been employed as screening tools and are currently being used in certain cases as an alternative technique for Gold (Au) and Silver (Ag) fire assays in gold mine laboratories. Linear regression analysis and other comparison analyses (discussed above) exhibit excellent agreement between fire assay techniques and XRF for the analysis of Ag and Au content in refinery pin samples. Cost savings are achieved through the reduction in preparation and analytical time, reduction in labor cost, and elimination of the consumption of reagent compared to fire assay analysis.
Examples from one specific mine show that it is possible to reduce the preparation and analysis time from 2 hours using conventional fire assay methods to 2 minutes using handheld XRF. Investigation with the XRF involves just rolling (flattening) the pin and carrying out multiple short tests (10 seconds in certain cases) at different places on the pin and computing the average.
Improvement in Laboratory Safety, Industrial Hygiene, and Environmental Performance
1. Laboratory Safety
- Handheld XRF avoids the need for using concentrated hydrochloric and nitric acids for preparing the sample, as necessitated by the fire assay techniques
- Handheld XRF prevents exposure of the technician to prospective skin burns and inhalation of lead fumes from the cupels and furnaces, which could happen while using the fire assay process
- The use of the handheld XRF reduces the heat fatigue due to the decrease in furnace usage and minimizes physical fatigue related to loading/twisting of furnaces
2. Industrial Hygiene
- Lower exposure to lead oxide (used in the fire assay techniques) leads to a potential advantageous effect on the levels lead in blood for the technician
- Real-time monitoring of levels of SiO2 dust in the laboratory and mine space — eliminates the need to wait for results from an offsite lab (turnaround times are usually 2 weeks)
3. Environmental Performance
- Handheld XRF enables real-time analysis of environmental samples (such as soil contamination and SiO2 dust) without depending on offsite laboratories
- Decrease in hazardous waste related to the fire assay techniques
Mill Feeds, Precipitates, and Bullion Penalty Elements
- Outstanding correlation exhibited between handheld XRF and ICP for Silica
- Using the XRF for everyday analyses of stockpile samples for silica helps metallurgists to remain informed about correlation between quartz content and potential lower gold recoveries related to grinding effectiveness
- XRF can be used to test refinery precipitate for Bi, Cu, Pb, Se, SiO2, and Fe
- XRF data can be used on Pin samples to ascertain penalty elements in bars and flux adjustments in precipitates
This information has been sourced, reviewed and adapted from materials provided by Evident (XRF / XRD).
For more information on this source, please visit Evident (XRF / XRD).