Method and apparatus for heat treatment of raw materials

An apparatus for the heat treatment of raw materials for the production of a melt, the apparatus comprising:

• a preheating chamber including a preheating chamber inner space and a preheating chamber heating element;
• and
• a plurality of microwave sections, each microwave section having a first chamber including a first chamber crucible, a first chamber inlet for a raw material leading to the first chamber crucible, at least one first chamber microwave generator, and a first chamber outlet for a melt formed from the raw material, having at least a second chamber including a second chamber crucible, a second chamber inlet for receiving the melt leading to the second chamber crucible, at least one second chamber microwave generator, and a second chamber outlet, and having one or more baffles or cascades arranged within the apparatus so that the melt flows over, under, or through an opening in at least one of the baffles or cascades,
• wherein the first chamber inlet receives the raw material from the preheating chamber.