A microwave reduction furnace including a reaction furnace provided with a refractory chamber of silica or silicon carbide for storing a material therein, a supply section for supplying the material into the refractory chamber, the material being a mixture of a silica powder and a graphite powder or a mixture of a silica powder, a silicon carbide powder and a graphite powder, a discharge section for discharging molten silicon, obtained through reduction, out of the chamber, and a microwave oscillator for outputting microwave toward the refractory chamber in the reaction furnace with a degree of directionality by virtue of a helical antenna or a waveguide.

A chemical reaction apparatus includes: a horizontal flow-type reactor inside of which has been partitioned into multiple chambers by multiple partition plates, and a liquid content horizontally flows with an unfilled space being provided thereabove; a microwave generator that generates microwaves; and at least one waveguide that transmits the microwaves generated by the microwave generator to the unfilled space in the reactor. The content flows over each of the partition plates, and, in each chamber, a weir height on an inlet side is higher than a weir height on an outlet side by at least an overflow depth at the partition plate on the outlet side.

A method for producing silicon using microwave and a microwave reduction furnace for use therewith are disclosed, with which it is possible to quickly reduce silica to quickly produce silicon. A material of a mixture of a silica powder and a graphite powder of a mixture of a silica powder, a silicon carbide powder and a graphite powder is set in a refractory chamber. Then, the material set in the chamber is irradiated with microwave. The graphite powder absorbs a microwave energy to increase the temperature, after which silica and graphite react with each other to further increase the temperature while producing silicon carbide, and the heated silica and silicon carbide react with each other. SiO produced through this reaction and silicon carbide are allowed to react with each other, thereby producing high-purity silicon.

In order to provide a treatment apparatus that can efficiently perform microwave irradiation, a treatment apparatus includes: a vessel made of a microwave-reflecting material, and having a first end and an irradiation opening portion, which is an emitting portion of microwaves that are emitted into the vessel; a first filter located so as to partition the vessel, and configured to separate solids that are to be separated, from the contents of the vessel; and a first reflecting member located closer to the first end than the emitting portion is and so as to partition the vessel, and configured to allow at least the contents having passed through the first filter to pass through the first reflecting member, and to reflect microwaves.