Abstract: A vortex combustion furnace (1) for the production of glass beads is generally cylindrical and has an outlet flue (24) at its upper end. A burner (13) at the lower end burns a gas/air mixture. Secondary air is introduced to the chamber through tangential air inlets (16) and creates a vortex within the chamber. The vortex has a top-hat temperature profile with a central heating region with a temperature in excess of 1000.degree. C. and a surrounding cooling region with a temperature not much above ambient. Glass cullet injected into the chamber follows a spiral path in the vortex, is heated, melts to form glass beads, is then cooled and finally is collected after striking the wall of the chamber.