Assay Sampling Protocols for Industrial Metal Scrap Valuation
Assay sampling protocols establish true dry weight and payable metal content, directly governing settlement values, working capital allocations, and lender borrowing base limits.
ICP OES
Meaning
Inductively coupled plasma optical emission spectrometry is an analytical instrument used to measure the concentrations of multiple elements in a liquid sample simultaneously. Operating an icp oes requires nebulising the liquid into an aerosol and carrying it into a high-temperature argon plasma. This excitation causes each element to emit characteristic light at specific wavelengths.
Sample Excitation
The liquid sample is pumped into a nebuliser to create a fine mist. This mist is carried by argon gas into the core of the plasma, which burns at nearly ten thousand Kelvin. At this extreme temperature, the molecules are broken down into individual atoms and ions.
These excited species emit light as they return to their ground states. This emission is then captured by the spectrometer to begin the detection process. The intensity of this light is directly related to the concentration of the element.
Elemental Measurement
Optical systems separate the emitted light into its component wavelengths. A solid-state detector measures the intensity of each wavelength to determine the concentration of the corresponding metal. This multi-element capability allows laboratories to scan for dozens of metals in a single run.
The instrument provides rapid throughput for busy commercial assay facilities.
Matrix Limitation
Samples containing high concentrations of dissolved salts or heavy metals can interfere with the light emission. This can lead to spectral overlaps or physical nebulisation errors. Chemists must dilute the sample or use internal standards to correct for these effects.
If the matrix is too complex, the accuracy of the assay will suffer.