Nickel is one of the key metals necessary for battery construction which is in high demand due to the current transition to green energy. Nickel is hosted in a variety of deposit styles and rock types, mafic intrusions, laterites, and sediments. This variety of host rocks and mineralisation styles require a diverse range of analytical methods.
Targeted exploration analysis for nickel can involve lithological studies which identify magmatic processes active in a suite of rocks. Identification of magmatic processes requires multi-element geochemical methods that represent the whole rock. These methods often require fusion decomposition to ensure all resistate minerals are broken down. For some situations a near-total four-acid digestion may be sufficient to provide the required information.
For nickel, analysis is ideal via a sodium peroxide fusion or four-acid decomposition, as opposed to a lithium borate fusion which may not fully recover base metals. Our multi-element sodium peroxide method analysed by ICP-MS (ME-MS89L™) reports low detection levels. A range of four-acid methods to suit all stages of exploration is also offered. Our super trace method (ME-MS61L™) reports nickel to our lowest level of 0.08ppm as described in the Generative Exploration section. Other Ni methods derived from a four-acid digestion include ME-MS61 with a detection level of 0.2ppm and ME-ICP61 with a detection level of 1ppm.
The choice of analysis method is influenced by sample mineralogy and expected concentration range for the elements of interest. When samples contain minerals that are resistant to acid digestions, which is commonly the case for ultramafic rocks, a fusion decomposition is required for fully recovery. Samples with a high percentage of sulphides require oxidising agents as part of the fusion to ensure full decomposition.
Ore grade nickel can be provided as a sole analyte (such as with four-acid methods Ni-AA62 and Ni-OG62, or sodium peroxide method Ni-ICP81), or from a multi-element suite (such as ME-ICP81). Multi-element analysis can provide valuable information at all stages of exploration and mining. Application of multi-element geochemistry at the mining stage can include monitoring of deleterious elements and geometallurgical assessment of ore. Sodium peroxide fusions are used to decompose sulphides, arsenides, chromite, rutile, ilmenite and titanite. For nickel sulphide analysis, a sodium peroxide fusion with ICP-AES instrument finish (ME-ICP81) is recommended.
|Analytes & Ranges (%)
Nickel laterites are formed by the weathering of ultramafic rocks and concentration of nickel into secondary minerals. Nickel can be hosted in goethite, smectite, adsorbed onto manganese oxides or as garnierite. Analysis of these samples is best achieved using a fusion decomposition due to the likely occurrence of acid-resistant minerals.
For nickel laterite samples, ALS recommends a fusion decomposition with XRF determination that includes a loss on ignition measurement. Results are typically reported un-normalised (ME_XRF12u), however, an option is available to normalise results to 100% (ME_XRF12n). This method is not suitable for samples with greater than 5% sulphide content as there is no oxidant added to the flux. For samples with higher sulphide content methods ME-ICP81, ME-XRF15b or ME-XRF15c are more appropriate.
|Analytes and ranges (%)
| Fused disc XRF,
LOI by furnace or TGA
These methods are designed to extract nickel sulphides while leaving nickel oxides and metallic nickel undigested. This is achieved by using a short digestion time at room temperature. These methods provide an approximation of the proportion of nickel present as sulphides, but some variation can occur due to sample mineralogy and the reaction of by-products. These methods are most powerful when combined with mineralogical investigations.
ALS offers two methods to selectively extract nickel sulphides: Ni-ICP05 and ME-ICP09. Both methods use acids that preferentially break down sulphides.
ALS can accept samples from most countries and regions with the correct paperwork. If you would like to submit samples from a country that doesn’t have an ALS lab, please contact the client services group for that region. A map of geochemistry locations is available under ‘Locations’ at the top of this page, with relevant contact details. Our client services team can provide information about import requirements for the region receiving the samples.
If you have special instructions for the laboratory, it is important to include these on the submittal form and contact client services at the receiving lab region to confirm instruction have been noted.
ALS offers a wide range of analytical methods for exploration applications for most geological sample materials.MORE INFORMATION
ALS has expert teams for mineralogy studies for all stages of exploration and mining.MORE INFORMATION