In order to dissolve minerals from its compound that are suitable for radiometricdating and to get rid of their adhesions in the best possible way, the stone is ground several times with the jaw crusher and the roller mill. The minerals suitable for the chosen dating methodology are separated using density differences, magnetic properties and grain shape. Subsequently, the millbase is sieved, the finer grain fraction is of interest for further processin.
The Wilfrey wet-shaking hearth works on the same principle as the washing pan and requires an enrichment of the heavy minerals. Roughly, very large sample quantities can be divided into fractions of different densities.
Mineral separation by means of heavy liquids
The heavy fractions from the wet-shaking hearth and pre-separated fractions by means of magnetic separators are further separated with heavy liquids such as bromoform (density 2.82 g / cm³) and diiodomethane (3.3 g / cm³). Light minerals such. As quartz or alkali feldspar float in bromoform. Heavy miners such. As zirconium, monazite, garnet sink in bromoform and diiodomethane.