Hoover and Strong offers a variety of analytical services to our customers. The technique used will depend on your budget, timeframe, the elements to be determined and the level of accuracy required.
It is our goal to recover the highest possible amount of gold, silver, platinum and palladium from your scrap material. Our leading-edge laboratory offers a variety of analytical techniques that are capable of detecting even the smallest amounts of precious metals. After your bullion has been weighed, drill samples are taken from each end and fire assayed in duplicate to determine the precious metal content. The results of the assays must agree. If they do not, the bar is remelted to ensure that it is homogeneous and then resampled and reassayed.
XRF: X-Ray Fluorescence Spectroscopy is a non-destructive technique capable of determining the concentration of multiple elements in a sample. It is particularly useful in providing qualitative results, defining the elements present in the sample with a less accurate determination of their concentration. This technique provides the most accurate results from smooth, flat, homogeneous samples. Please note that the XRF spectrometer cannot determine elements lighter than aluminum.
Accuracy: GOOD ± 0.1% for gold & ± 0.5% for all other metals. Results are dependent on sample quality and homogeneity.
Cost: $25 per sample
Turnaround: One working day from receipt of sample
FIRE ASSAY: This is the oldest and arguably the most accurate method for determining gold content. This ancient technique is still used today and requires a small amount of your sample to undergo a thermal and chemical process. Samples must be homogeneous.
Accuracy: BETTER ±0.01% or better
Cost: $50 per sample
Turnaround: Two working days from receipt of sample
ICP-OES: Our most precise technique utilizing Inductively-Coupled-Plasma Optical Emission Spectroscopy (ICP-OES). This method is capable of simultaneously detecting multiple elements in a sample and providing their concentration at the parts per million level (PPM). Sample preparation and processing time for this technique however, takes much longer than the two processes mentioned above. Single and multiple element analysis are available.
Accuracy: BEST ±10 Parts per million (PPM)
Cost: $75 for a single element and up to $275 for multiple elements per sample
Turnaround: 1-2 weeks from receipt of sample
Samples submitted for analysis must be homogenous and in a solid form for accurate results. A melt charge of $100 will be levied if this is necessary for the analysis.