Rotary kiln

A rotary kiln comprising:

• a sintering device provided with a cylindrical rotation tube configured to mix a powder raw material, the cylindrical rotation tube being configured to rotate about a horizontal axis, the horizontal axis being parallel to a central longitudinal axis;
• an external heating device configured to heat the powder raw material input into the rotation tube, the external heating device being configured to heat an exterior of the rotation tube;
• and
• an internal heating device configured to simultaneously stir and heat the powder raw material input into the rotation tube,
• wherein the internal heating device comprises:
• a microwave generation part configured to generate microwaves;
• a guide part configured to guide the microwaves into the rotation tube;
• and
• a stirring heat generation part coupled to an inner circumferential surface of the rotation tube,
• wherein the stirring heat generation part is configured to stir the powder raw material input into the rotation tube and the stirring heat generation part is configured to absorb the microwaves to generate heat, and
• wherein the stirring heat generation part comprises:
• a coupling rod disposed on the inner circumferential surface of the rotation tube, the coupling rod being parallel to the horizontal axis;
• at least one stirring heat generation element configured to be coupled to the coupling rod, the at least one stirring heat generation element being configured to stir the powder raw material input into the rotation tube and being configured to absorb the microwaves to simultaneously heat the powder raw material;
• and
• a coupling piece configured to couple each of both ends of the coupling rod to the inner circumferential surface of the rotation tube, and
• wherein, the at least one stirring heat generation element includes a plurality of stirring heat generation elements, wherein an auxiliary tube is configured to be fitted and coupled to the coupling rod, the auxiliary tube being fixed between the plurality of stirring heat generation elements, and wherein the auxiliary tube is configured to be incapable of heat generation by absorption of the microwaves.