Analytical Suite Metadata

ActLabs 1A3-Ag: Au, Ag Fire Assay - Gravimetric

ActLabs Code 1A3-Ag – Au, Ag Fire Assay Gravimetric; 29.16g sample weight; 0.03-10,000 g/mT (Au), 3-1,000 g/mT (Ag)

General Methodology:

A sample size of 5 to 50 grams can be used but the routine size is 30 g for rock pulps, soils or sediments (exploration samples). The sample is mixed with fire assay fluxes (borax, soda ash, silica, litharge) and with Ag added as a collector and the mixture is placed in a fire clay crucible. The mixture is then preheated at 850°C, intermediate 950°C and finish 1060°C with the entire fusion process lasting 60 minutes. The crucibles are then removed from the assay furnace and the molten slag (lighter material) is carefully poured from the crucible into a mould, leaving a lead button at the base of the mould. The lead button is then placed in a preheated cupel which absorbs the lead when cupelled at 950°C to recover the Ag (doré bead) + Au.

The cupellation of the bead is controlled by the volatility of the silver. The Ag bead is weighed and Ag value calculated from the weight. Au is separated from the Ag in the doré bead by parting with nitric acid. The gold (roasting) flake remaining is weighed gravimetrically on a micro balance for Au.

[description retrieved on 2016-02-01 from]

Instrument: unstated

Sample material: solid

Sample weight: unstated

Analytical Technique:

Hierarchical classification

Technique >> Gravimetry >> Weighing



Analytical Decomposition:

Hierarchical classification

Decomposition >> Fusion >> Fire Assay


Pb | PbO/Ag | NiS

Analytical Methods:

IndexMethod OrderMethod IDQuantityDetection Limit
1  5469     Au_FA_GRA  0.03
2  5470     Ag_FA_GRA  3

Associated Analytical Packages:

IndexPackage IDPackage Name
1  296     ActLabs GSC TGI4 whole rock analysis (variant #1)
2  297     ActLabs GSC TGI4 whole rock analysis (variant #2)
3  298     ActLabs GSC TGI4 whole rock analysis (variant #3)
Date modified: