Thermo Fisher Scientific has developed a system to provide fast and efficient impurity analysis of solid metals, including steels, platinum group metals, gold and other conductive materials.
Combining the Thermo Scientific iCAP 6500 Duo ICP emission spectrometer with a separate sampling and excitation accessory (SSEA), the system allows close monitoring of all stages of the silver refinery process.
The iCAP 6000 Series allows the sensitive, multi-element determination of impurities at ppb and sub-ppb levels in liquid-phase matrices, and by adding the SSEA accessory, solid- phase metallic matrices can also be analysed with minimal sample preparation.
Silver refinery plants receive low-assay silver from suppliers and have to analyse the silver, gold and platinum group metals (PGM) content as well as toxic and harmful elements which may interfere with the refinery process.
Impurities present in silver require the reprocessing of contaminated products, resulting in metal and cost losses.
As a consequence, the maximum total concentration of impurities allowed in saleable silver bullion is less than 100ppm with the required detection limits for each impurity less than 1ppm in solid.
ICP emission spectrometry has been traditionally used for the analysis of silver, but this method is associated with extensive sample preparation.
By using an SSEA, sample preparation is greatly reduced, allowing for rapid silver analysis in minutes compared with traditional ICP spectrometry, which takes hours in sample digestion.
The Kolyma State Refinery, based in the Magadan region of Russia, uses the iCAP 6500 Duo with SSEA for routine analysis of an extended range of silver products, including low- assay silver and high-purity silver.
Using the iCAP 6500 Duo SSEA system, silver values are determined by concentration ratios to give a final silver concentration.
Following 10 replicate analyses of a high-purity silver sample, the standard deviation of the impurity results is multiplied by three.
The results further support the capabilities of the method for high-sensitivity, multi-element determination of impurities at ppm and sub-ppm levels in solid silver matrices, as well as the ability to determine the silver content itself.
High repeatability is also demonstrated.
The iCAP 6500 Duo features superior sensitivity in axial view, as well as electronic control and triggering capabilities, so is able to couple with and fully support an SSEA.
Using a bloom-resistant CID camera, the iCAP 6500 can analyse for trace elements in the presence of high-intensity emissions, while allowing full wavelength coverage and maximum resolution, thereby reducing interferences.
