The use of an induction furnace for rapid radiochemical separations in neutron activation analysis of rocks is discussed in general and the activation analysis of sulphur in geological samples is described as a specific application. After irradiation the sample is heated in an induction furnace in a flow oxygen. The expelled sulphur oxides are adsorbed onto activated charcoal and measured in the well of a sodium iodide detector. The 3102 keV peak of the 5 minute37S is used for analysis. The separation time is seven minutes, the yield 99% and the detection limit 200 μg S. Results of the analysis of ores are presented.