Dr. Joachim Janus
Diplom-Chemiker Diplom-Wirtschaftschemiker
Wollseifener Str. 6 ∙ D-52152 Simmerath
Analysis of Precious Metals
The analysis of precious metals, especially the quantitative gold analysis, is still today carried through predominantly in the conventional way.
The modern instrumental methods, e.g. atomic absorption spectroscopy (AAS) or X-ray-fluorescence are more and more improved upon, but with the analysis of gold alloys, e.g. from jewellery or dental alloys, their accuracy does not reach the from fire essay usually expected - and requested - level.
It is true, the spectroscopic methods are fast and comfortable, but their range of application is reduced to diluted solutions and alloys with very low contents of precious metals.
The historic fire essay is lengthy and requires much labour, but it is the only method, which yields sufficient exact and reliable results (with Au ± 0,1 ‰), and Ag as well as Pt and Pd can be analysed with little additional expenditure.
It is a prerequisite for an appropriate application to use best possible implements.
Exact, comfortable and quickly weighing analytical balances are available today.
The essential item of the analytical equipment is the refining furnace. Muffle furnaces heated by gas are uncomfortable for the analytic chemist because of their noise, and the exact temperature adjustment requires much experience; besides that the wear of the muffles is high.
An appropriate electric furnace works noiseless, it dos not produce waste gas, the useful life of the muffles is longer, and the adjustment of the temperature is electronically exact.
The separation of the precious metal buttons coming from the muffle furnace is still today effected in a Kjeldahl flask. It should be heated by an air bath, which avoids reliably the feared delays in boiling.
Besides some further details an effectively working controlled ventilation is necessary, in order not to violate worker's protection laws. An additional waste air purification is normally only under more critical conditions necessary (e.g. in a city centre).
The individual design, delivery and erection of complete analytical laboratories as well as the education of your staff belong to our program. We are ready for more detailed informations without obligation.