A method and apparatus for thermally reacting one or more inorganic materials, the method involves the step of maintaining a flame in a combustion chamber at a predetermined reaction temperature by supplying a sufficient quantity of a hydrocarbon fuel and oxygen into the flame through a fluid stream comminuting the inorganic materials to be reacted to a particle size which can be transported by gas flow and suspending the comminuted inorganic compound in an intimate admixture with the fluid stream containing the hydrocarbon fuel and oxygen and passing the admixture to the interior of the flame to effect thermal reaction of the particulate inorganic material. The apparatus can comprise a blower, a grinding means, a furnace means, and a means for collecting the reacted material.