Gold cyanidation

Cyanide leaching

Cyanide leaching was first applied to extract gold from pyritic ore, which prior to the discovery of gold cyanidation could not be extracted. This led to heavy investment in mining in the 1890s and the opening of larger gold mines. Leaching gold with cyanide is still a widely used hydrometallurgical process in today's mining industry. Cyanide methods are applied to samples from many stages of the mining cycle. These methods can be used in exploration on large-sized soil or sediment samples to identify anomalies, or drill samples with known mineralisation to identify cyanide soluble minerals.

Cianidação de ouro

Gold by cyanide leach analysis

Cyanide leaches are a routine analytical method used during resource drilling as a first pass estimation of how an ore will behave during cyanide hydrometallurgical processing. ALS has a number of method options available for cyanide leach with AAS finish.

Gold Cyanidation methods

Code Analyte Range (ppm) Description
Au-AA13
Ag-AA13
Cu-AA13		 Au
Ag
Cu		 0.03-50
0.03-350
0.1-2,000		 Au, Ag, Cu by cyanide leach with AAS finish.
30g sample
Au-AA14 Au 0.01-200 Au by cyanide leach with AAS finish. 12hr Leach.
Up to 1kg sample
Au-AA15a
Au-AA15b
Au-AA15c
Au-AA15d		 Au 0.001-125 Au by accelerated cyanide leach using LeachWELL Assay Tabs™ with AAS finish. 4hr Leach.
500g sample request Au-AA15a
For 1kg request Au-AA15b
For 2kg request Au-AA15c
For 3kg request Au-AA15d
Au-AA31
Au-AA31a		 Au 0.03-500 Au Preg Rob Leach with Gold Spike.
Au Preg Rob Leach without Gold Spike.
10g sample per method

Super trace gold analysis by cyanide extraction

For gold exploration, cyanide leaches can be used to analyse soils and sediments to levels below crustal abundance. Cyanide leach provides ALS's lowest gold detection limit which is possible due to the stability of gold cyanide complexes coupled with ICP-MS instrumentation optimised for gold sensitivity. Cyanide leaches have lower matrix effects and lower dilution factors compared to aqua regia digestion, which enables detection levels for gold to be five times lower.

Super trace methods - Au-CN43TM & Au-CN44TM

Code Analyte Range (ppm) Description
Au-CN43™
Au-CN44™		 Au 0.02ppb-1ppm Au by cyanide extraction with ICP-MS finish. 25g sample
Au by cyanide extraction with ICP-MS finish. 50g sample

Related resources

Bulk Leach Extractable Gold

Cyanide for bulk leach extraction

Cyanide is used in bulk leach extraction methods which are designed to overcome nugget effect in the sampling of gold bearing materials.

MORE INFORMATION

Downloads

pdf

ALS Cyanide Leach Tech Note

4 JUL 2024

pdf

The importance of low detection levels for gold

17 JUN 2022