Abstract: Apparatus for drying material which is mixed with a solvent. Material and solvent are mixed in a mixer (1) and simultaneously vibration energy is radiated by one or more high frequency vibration generators (9) towards the free surface (10) of the mixture mass in the container with a frequency of 2450 MHz.Thereby the solvent, which is a polar material, is heated and vaporized so that a quick drying of the product is obtained without damage thereto.The structure of the apparatus is such that also when no product is present leakage radiation remains within the safety limits and a minimal reflection of the radiated energy within the apparatus takes place.