A reactor for molybdenum sulphide (MoS2), wherein MoS2 is ionized by an electric field generated by a first set of magnetrons at a frequency in the range of 2500-3500 MHz and heated by a variable magnetic field of 2500 Hz produced by a winding coil, resulting in the exclusive evaporation of molybdenite. MoS2 in gas state is then stimulated by a second set of magnetrons and, with the injection of air, oxidized until trioxide is obtained. Hot gases essentially containing molybdenum trioxide, sulphur dioxide, and nitrogen are conducted from a first body towards a second body though a first duct. Cold air is added to the second body through a second duct to cool the gas, and crystals formed by liquefaction settle and are removed through a lower duct while gases at a temperature of 600° C. are conducted through a higher duct.