An apparatus for producing ignitable solids-gas suspensions has a feeder for vertically feeding the solids-primary gas suspension, a secondary gas passage concentrically surrounding said feeder, and a stage for mixing both streams. In order to improve the igniting and melting of solids-gas suspensions in such apparatus, the feeder for the solids-primary gas suspension consists of a pressure relief vessel, which is provided with a tangentially extending supply line for supplying the solids-primary gas suspension, which supply line opens into said vessel in a substantially horizontal direction, and in that the pressure relief vessel is succeeded by two series-connected mixing stages which consist of venturi diffusers, the secondary gas passage concentrically surrounds the diffuser in the first mixing stage and the second mixing stage contains a flame-sustaining annular gas burner having fuel gas and oxygen nozzles arranged in alternation and surrounding the diffuser outlet, which is provided with a cooling chamber. The entire burner apparatus is mounted on the top rim of a vertical combustion shaft, which opens into a horizontal melting cyclone chamber.