Abstract: Method and device implemented in a reactor for the plasma treatment of carried fragmented material or of pulverized elements by a support gas where the main element is an intermediate temperature plasma (PIT) generator fed by a source of electric pulses, the amplitude of whose current is limited and for which the generating frequency, the duration of the pulses and the duration of the time spans between the pulses are determined in such a way as to generate a nonthermal plasma (PIT) of large extent, the plasma and the carrier gas flux (4) laiden with the fragments of material or of pulverized elements to be treated (5) moving along helical trajectories coaxial with the axis of the reactor at controlled angles a and B respectively relative to the plane perpendicular to the axis of the reactor, the angles a and B being able to vary in a given manner according to the properties of the material to be treated and the technological parameters and the dimensions of the reactor.