A gas converter is disclosed, especially for the treatment, including dissociation, of gases produced in the pyrolysis of waste materials. The converter includes a feeder for airtight feeding of fuel from the upper region of the reactor tower to the bed of hot fuel, a gas outlet, and a slag removal system. The reactor tower is furnished at its lower end near the conduits for the admission of air and gases with a rotating distributor member. The feeder is provided by a bucket-wheel valve arrangement.