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Whole rock analysis

Whole rock analysis

Whole rock analytical methods are required when lithogeochemical classification by geochemistry will be applied. Whole rock methods all involve a fusion decomposition that breaks down all minerals in the sample, therefore liberating all elements for analysis. Also, methods for the major rock forming element determinations do not use hydrofluoric acid that volatises Si as SiF4 so that silicon can be reported.

Análise de rocha inteira

Whole rock analysis

Both XRF and ICP-AES instruments can be utilised to determine the major rock-forming elements following a lithium borate fusion. These methods are not suitable for samples with base or precious metals mineralisation. Specific commodities such as iron ore, bauxite, and base metal sulphides should be analysed with methods designed for those sample types as the flux and instrument calibration are optimised for them.

Methods available

ALS offers method ME-XRF26 which is an XRF measurement on a fused disc. Alternatively, an ICP-AES measurement method on a fused sample is an option by ME-ICP06. With XRF analysis the fused disc is analysed directly by the instrument, however, when measuring a fused sample by ICP-AES, there is an extra digestion step required to dissolve the fused sample for introduction to the ICP-AES as a solution.

Code Analytes and ranges (%) Description
ME_XRF26*
2g sample		 Al2O3 0.01-100 Fe2O3 0.01-100 Na2O 0.01-10 SrO 0.01-1.5 Fused disc XRF,
LOI by furnace or TGA
BaO 0.01-66 K2O 0.01-15 P2O5 0.01-46 TiO2 0.01-30
CaO 0.01-60 MgO 0.01-50 SO3 0.01-34 LOI 0.01-100
Cr2O3 0.01-10 MnO 0.01-39 SiO2 0.01-100
*For unmineralised samples with moderate sulphide content, please request ME_XRF06.
For mineralised and/or high sulphide content >4%, please request ME-XRF15c.
Performed on dried sample therefore expected to report slightly higher than ME_XRF06.




Code Analytes and ranges (%) Description
ME_ICP06*
2g sample		 Al2O3 0.01-100 Fe2O3 0.01-100 Na2O 0.01-100 TiO2 0.01-100 Fused bead,
acid digestion
and ICP-AES.
LOI by furnace
or TGA
BaO 0.01-100 K2O 0.01-100 P2O5 0.01-100 LOI 0.01-100
CaO 0.01-100 MgO 0.01-100 SiO2 0.01-100
Cr2O3 0.002-100 MnO 0.01-100 SrO 0.01-100
*For mineralised and/or high sulphide content >4%, please request ME-XRF15c.
Both the ME_XRF26 and ME_ICP06 packages include LOI by furnace or TGA.


Trace elements by lithium borate fusion

Fusion with lithium borate flux followed by acid dissolution of the fused bead coupled with ICP-MS analysis provides a quantitative analytical approach for a broad suite of trace elements. To this, whole rock analytes may be added by analysing the same digested solution by ICP-AES, or base metals from a separate four-acid digestion and ICP-AES.

Methods available

ALS offers method ME-MS81™ to determine trace elements from a fused sample with ICP- MS instrument analysis. To add a whole rock analysis (ME-ICP06) to the trace elements (ME- MS81™) an economical package ME-MS81d is available. There is also an option to add base metals from a four-acid digestion by requesting ME-4ACD81.

Code Analytes and ranges (ppm) Description
ME-MS81™
2g sample		 Ba 0.5-10,000 Hf 0.1-10,000 Sn 1-10,000 Y 0.1-10,000 Fused bead,
acid digestion
and ICP-MS
Ce 0.1-10,000 Ho 0.01-1,000 Sr 0.1-10,000 Yb 0.03-1,000
Cr 10-10,000 La 0.1-10,000 Ta 0.1-2,500 Zr 2-10,000
Cs 0.01-10,000 Lu 0.01-1,000 Tb 0.01-1,000
Dy 0.05-1,000 Nb 0.1-2,500 Th 0.05-1,000
Er 0.03-1,000 Nd 0.1-10,000 Tm 0.01-1,000
Eu 0.02-1,000 Pr 0.02-1,000 U 0.05-1,000
Ga 0.1-1,000 Rb 0.2-10,000 V 5-10,000
Gd 0.05-1,000 Sm 0.03-1,000 W 1-10,000

Frequently asked questions

Related Topics

Complete Characterisation Packages

Complete characterisation

There is no single analytical method that can determine all elements in a rock. ALS offers packages for complete characterisation.

MORE INFORMATION
Fusion Decomposition

Trace elements

When low detection levels are needed for trace elements, method ME-MS89L™ may be useful.

MORE INFORMATION
 
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