The value and assorted uses of gold, platinum and palladium are well known. However, there are a growing number of uses for the rarest of the Platinum Group Elements (PGEs): rhodium (Rh), ruthenium (Ru), iridium (Ir), and osmium (Os) in new technology applications. This, along with their high market price, makes them potentially valuable by-products. Gold, platinum, and palladium may be determined by standard lead oxide collection fire assay and ICP-MS or ICP-AES finish. For the full suite of platinum group elements, nickel sulphide collection fire assay must be used for quantitative results.
Homogenised and pulverised samples are mixed with flux composed of PbO and SiO2 with variable amounts of borax, soda ash and other reagents. The flux and sample are mixed, then heated at high temperature (>1,000°C) to decompose rock lattices and allow precious metals within the sample to be collected into a lead button. The button is placed in a porous cupel and heated again in an oxidising environment to convert lead to lead oxide that is absorbed into the cupel, leaving the precious metals behind as a doré bead or prill. The gold, platinum and palladium content of the prill is then determined spectroscopically.
Code | Analyte | Range (ppm) | Description |
---|---|---|---|
Trace Level | |||
PGM-MS23L | Pt Pd Au |
0.0001-1 0.0002-1 0.001-1 |
Super trace Pt, Pd and Au by fire assay and ICP-MS finish. 30g nominal sample weight |
PGM-MS23 PGM-MS24 |
Pt Pd Au |
0.0005-1 0.001-1 0.001-1 |
Pt, Pd and Au by fire assay and ICP-MS finish. 30g Sample Pt, Pd and Au by fire assay and ICP-MS finish. 50g Sample |
PGM-ICP23 PGM-ICP24 |
Pt Pd Au |
0.005-10 0.001-10 0.001-10 |
Pt, Pd and Au by fire assay and ICP-AES finish. 30g sample Pt, Pd and Au by fire assay and ICP-AES finish. 50g sample |
Ore Grade | |||
PGM-ICP27 | Pt Pd Au |
0.01-100 0.01-100 0.01-100 |
Pt, Pd and Au by fire assay and ICP-AES finish. 30g nominal sample weight |
A 30g sample is fused with a mixture of soda ash, borax, silica, sulphur and nickel carbonate or nickel oxide at >1,000°C to produce a nickel sulphide button. The button is weighed then milled to a fine powder before dissolution in hydrochloric acid. The platinum group elements and gold are precipitated as tellurides on a cellulose nitrate membrane filter which is then digested in hydrochloric and nitric acids. The final solution is analysed by ICP-MS.
Code | Analyte | Range (ppm) | Description |
---|---|---|---|
PGM-MS25NS | Pt, Pd | 0.002-15 | Au, Pt, Pd, Ir, Os, Rh, Ru by nickel sulphide collection fire assay and ICP-MS finish. 30g nominal sample weight. |
Au, Rh | 0.002-5 | ||
Ir | 0.001-5 | ||
Os | 0.002-1 | ||
Ru | 0.003-5 |
Rhodium analysis is carried out in a similar manner to PGM by lead collection fire assay, with the additional step of gold inquarting during the fusion process and modified cupellation. Analysis is carried out using ICP-MS instrumentation.
Code | Analyte | Range (ppm) | Description |
---|---|---|---|
Rh-MS25 | Rh | 0.001-1 | Rh by fire assay, gold collection and ICP-MS. 30g nominal sample weight |