Abstract: The present invention relates to a fluidized-bed reactor for the thermal treatment of fluidizable substances, comprising at least one means for feeding microwave radiation into the fluidized-bed reactor and a metallic reactor wall defining the reactor and having a thermal insulation coating. To increase the energy utilization of such reactors, it is proposed in accordance with the invention that the thermal insulation coating is provided on the inside of the reactor wall and has an outer layer as seen from the reactor wall, which comprises refractory brick and/or refractory concrete as well as an inner layer comprising light-weight refractory brick and/or insulating concrete.

Abstract: The invention relates to a method and a plant for the heat treatment of sulfidic ores, in which solids are heated to a temperature of approximately 450 to 1500° C. in a fluidized bed reactor (1). In order to improve the energy utilization, it is proposed to introduce a first gas or gas mixture from below through a gas supply tube (3) into a mixing chamber (7) of the reactor (1), the gas supply tube (3) being at least partly surrounded by a stationary annular fluidized bed (35) which is fluidized by supplying fluidizing gas. The gas velocities of the first gas or gas mixture as well as of the fluidizing gas for the annular fluidized bed (35) are adjusted such that the particle Froude numbers in the gas supply tube (3) are between 1 and 100, in the annular fluidized bed (35) between 0.02 and 2 and in the mixing chamber (7) between 0.3 and 30.

Abstract: A gas mixture comprising molecular oxygen and 15 to 60 vol-% SO2 flows through a first catalyst layer which contains a catalyst containing vanadium pentoxide, and directly subsequently through a second catalyst layer which contains a catalyst containing iron. With an inlet temperature of 350 to 600° C., the gas mixture is introduced into the first catalyst layer which contains a granular V2O5 catalyst and 20 to 80 wt-% catalytically inactive inert material. Directly subsequently, the gas mixture is introduced into the second catalyst layer with a temperature of 500 to 750° C. Preferably, the catalyst of the second catalyst layer contains 3 to 30 wt-% arsenic oxide. There is produced an SO3-containing product gas with a volume ratio of SO2: SO3 of not more than 0.1.