Sorting in an electrostatic field is a processing step, which attracts extractive industry’s notice – especially the industrial minerals industry - because of its dry operational mode and the possibilities of specific interaction with multiple processing relevant parameters. Distinctiveness is given by the necessity of controlling the process environment, such as adjusting of a specific humidity and temperature, which (may) have great influence on the separation behaviour. To condition the grains’ surface reagents can also have influence on the charging behaviour and subsequently on the separation sequence’s selectivity. Superordinate scope of this thesis is to investigate the efficiency of electrostatic sorting by triboelectric charging for processing magnesite ores of Austrian origin. A matter of particular interest is possibility to obtain magnesite concentrates of high quality through the application of specific reagents. On the one hand a depletion of siliceous mineral components is important and it’s also on the other hand essential to separate occurring carbonaceous accompanying minerals calcite and dolomite. In this thesis experiments were made with several reagents and their effect on the separation of magnesite from siliceous components as well as the carbonaceous minerals calcite and dolomite was determined. Magnesite ores from four different deposits were investigated. All deposits are property of STYROMAG GmbH. The experimental run Kaintaleck was the basis for all further investigations. Within this run the influences of many parameters were investigated e.g. reagent type and its amount, periods and possibilities of conditioning, charging devices, humidity and temperature and also with single- and two-stage process. With all those expertise of magnesite ores of the deposit Kaintaleck gained, further experimental runs were customised for the other deposits Hohentauern, Wald am Schoberpass and Angerer. Those runs were processed henceforth in two steps. In a first step siliceous components were degraded in an unconditioned mode. In a second step the remaining intermediate fraction was conditioned hereupon with selected reagents and separated in the electrostatic field again. All samples were analysed in STYROMAG GmbH’s company own laboratory. The data gained were transferred into mineral processing balance tables and the results were shown in limit curves of selectivity according to Steiner in order to illustrate processing efforts. Amongst other things determinations were made that an accurate procedure of systematic experimental runs is of particular importance in order to find ideal working units, that currently better results can be achieved in depleting siliceous minerals in comparison to carbonaceous accompanying minerals and finally that some of the tested reagents contribute to an enhancement / increase of selectivity.