Analysis Technology: Methods and Devices
About Analysis
In our laboratory, we use classical wet chemical methods such as gravimetry, volumetry, electrogravimetry, instrumental analytical methods and melt extractions for the main and minor group elements, especially for the precious metals Ag (silver), Au (gold), Pd (palladium), Pt (platinum) and Rh (rhodium).
Extraction of Precious Metals:
For precious metal analysis, we prefer to work with the methods established under the term docimasy (fire assay). This includes melting (1000 – 1200°C) and collecting the precious metals gold (Au), silver (Ag), platinum (Pt), palladium (Pd) with lead (Pb). The Pb can be partially or completely expelled. The remaining precious metal grain is either analyzed for its components Au, Pd and Pt using ICP-OES, titrated (Ag), or the Au is determined gravimetrically (roll sample).
Other collectors such as copper (Cu) or nickel sulphide (NiS) are often used specifically for the platinum group metals platinum (Pt), palladium (Pd), rhodium (Rh), iridium (Ir) and ruthenium (Ru). The docimastic methods separate the often interfering matrix of the sample material and enable instrumental analysis with a constant matrix of Cu or Pb while simultaneously enriching the precious metals Ag, Au, Pd, Pt, Rh, Ir, Ru. We have a large number of chamber furnaces for melting and driving work, so that there are no bottlenecks in the collective melting of Ag, Au, Pd, Pt, Rh, Ir, Ru.
Analysis Technology with Inductively Coupled Optical Emission Spectrometry (ICP-OES):
With the ICP-OES technique, we are able to analyse almost all elements of the periodic table of elements. We have two ICP-OES spectrometers at our disposal: ThermoFisher iCap 6300 (radial and axial observation of the plasma) and Spectro Arcos (radial observation). We also use the Analytik Jena Plasma Quant ICP-MS for trace levels. The working range is between 0.001 and 200 mg/L.
Certified or validated standard solutions with metrological traceability are a prerequisite for reliable results.
For stable measurements, we use the bracketing method, among other things.
Analysis Technology with Wavelength Dispersive X-ray Fluorescence Spectrometer (WD-XRF):
With this measuring method, all precious metals Ag, Au, Pd, Pt, Rh, Ir, Ru collected with Cu-docimania are measured in the copper king/copper regulus using specially calibrated methods. The accuracy is checked using natural reference material and synthetically produced comparators made of pure metals, the purity of which is checked by Elmaspecs using GDMS (Glow Discharge Mass Spectrometry) before use. The WD-XRF can analyse concentration ranges from 1 – 2 ppm up to 100% depending on the sample weight and the elements to be determined. We use the Axios (MalvernPanalytical) with a 4 KW molybdenum tube.
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Analysis of trace elements in a wide variety of sample material.
Myint Myint Sein, Wolfgang van Leeuwen and Peter Glörfeld (2017) Combination of fire assay and modern instrumental techniques for precious metal analysis, In: Production and recycling of non-ferrous metals: Saving resources for a sustainable future, European Metallurgical Conference EMC 2017, Vol. 4, 1785 – 1796.
Frequently Asked Questions (FAQ)
Which analysis methods are used in your laboratory?
We use classic wet-chemical methods such as gravimetry, volumetry and electrogravimetry as well as modern techniques such as ICP-OES, ICP-MS and WD-XRF.
How does precious metal analysis work in your laboratory?
For the analysis of precious metals we use methods of docimasy. Precious metals such as gold, silver, platinum and palladium are enriched by melting and collecting them with lead, copper or nickel sulphide and then analysed.
Which devices are available for the analysis technology?
Our laboratory has three ICP spectrometers (Spectro Modula, Spectro Arcos, ICAP 6300 DUO), a wavelength dispersive X-ray fluorescence spectrometer (WD-XRF) and several chamber furnaces for melting and forcing work.
Welche Geräte gibt es für die Analysetechnik?
Our methods cover concentrations from 0.1 mg/L to 100%, depending on the method and sample weight.
How is the accuracy of the analyses ensured?
Our results are checked with natural reference material and synthetic reference samples. We also use pure metals whose purity is carefully checked before use.
Can trace elements be analysed?
Yes, with our ICP-MS system we can precisely analyse trace elements in a wide variety of sample materials.