Precious Metals Analysis
Accurassay Laboratories is pleased to offer a high calibre analytical capability, with high sample capacity, reliable quality and fast turnaround service for these key precious metals: Au, Ag, Pt, Pd, Rh. All of our precious metals analyses are performed using our Fire Assay procedure combined with multiple finishes( AAS, ICP, and Gravimetric). These combinations allow for a wide spectrum of detection limits (from 1ppb to 1%) and raw sample concentrations.
Historically, the analysis of gold has been performed using a 30g sub-sample during the fire assay procedure. A 50g sub-sample can also be used to help increase the sensitivity of gold detection while decreasing the sampling error. However, high levels of base metals, chromium, selenides and tellurides can reduce the effectiveness of the gold collection. Accurassay Laboratories may decrease the subsample size during fusion to overcome these effects.
For a more comprehensive analysis of gold in rock/core, we would recommend the Pulp Metallic procedure. This procedure is able to overcome the “Nugget Effect” of gold by increasing the sub-sample size to 1,000g and physically collecting the free gold within the system using a 150 mesh (106μ) sieve. This procedure is most effective when the whole sample is used for the analysis. The sub-sample is pulverized to ~90% -150 mesh (106μ) and subsequently sieved through a 150-mesh (106μ) screen. The entire +150 metallics portion is assayed along with two duplicate sub-samples of the -150 pulp portion. Results are reported as a weighted average of gold in the entire sample.
For the analysis of gold in soils, sediments, and tills we recommend using a 50g sub-sample for the fire assay procedure with an ICP finish with the lower detection limit of 2ppb.
For a more comprehensive analysis of both the gold content of the sample and the particulate size of the gold within the material, we recommend a Screen Metallic analysis. Screen Metallics analysis includes the crushing of the entire sample to 90%-10 mesh and using a Jones Riffler (unbiased splitter) to split the sample to a 1kg sub-sample. The entire sub-sample is pulverized and subsequently sieved through a series of meshes (80, 150, 200, 230, 400 mesh). Each fraction is then assayed for Gold (maximum 50g.). Results are reported as a calculated weighted average of Gold in the entire sample.
Platinum Group Elements (PGEs)
The analysis for PGEs can be achieved through the use of the fire assay technique, combined with AAS, ICP, or INAA finish methods.