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How to Identify Nickel in a Fire Assay

Identifying nickel deposits in a field location can be accomplished through several methods. Scientists test plant life with biogeochemical assays and earth samples with fire assays. Though fire assays are typically used to discern the presence of precious metals such as gold, platinum or palladium, the assay can also divulge information about other elements. The fire assaying process requires sample preparation and exposure to high temperatures (often over 1100 degrees C). By utilizing different preparation steps, this process can identify and quantify nickel and other metals.

Things You'll Need

Nitric acid
Fire assaying furnace
Argon-based, high temperature radio frequency plasma
Inductively coupled plasma mass spectrometer
Electron multiplier detector

Instructions

- 1
  Select a field sample and record its characteristics, mass and dimensions. Preserve the sample with nitric acid. In the assaying facility, crush the ore sample. Divide the sample into several smaller aliquots.
- 2
  Perform a gold-detecting fire assay on one or more aliquots. Lead carries the precious metals to the bottom. The slag remaining upon the surface reveals other metals through coloration. Brown to black coloration identifies nickel's presence.
- 3
  Aspirate one or more aliquots into an argon-based, high temperature radio frequency plasma. This dissolves, atomizes and ionizes the aliquot. With an inductively coupled plasma mass spectrometer (ICP-MS), isolate and extract nickel ions from the plasma based upon their mass to charge ratio.
- 4
  Count ions with an electron multiplier detector. Process the resulting information with a computer to quantify the amount of nickel in each aliquot.

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