Method and apparatus for denitration of nitrate solution by microwave heating

In an apparatus for denitration of a nitrate solution which is a substance to be treated, including an oven having a microwave waveguide tube and a gas discharging tube, and a microwave generator connected to the waveguide tube, the improvement comprising:

• the oven being cylindrical in shape and having a construction capable of being separated into an oven upper part and an oven lower power, the upper and lower parts being coupled through a choke coupling mechanism to form the cylindrical oven, the oven lower part constituting a closed-bottom vessel for receiving therein the substance to be treated by microwaves applied from the microwave generator, the lower part being horizontally rotatable by a rotary unit, the oven upper part being provided at a top wall thereof with the waveguide tube and the gas discharging tube, a detector for detecting the amount of reflected waves of applied microwaves being provided along the waveguide tube and the reflected wave detector being electrically connected with the microwave generator through a control unit which controls microwave power of the microwave generator according to the amount of reflected waves detected by the reflected wave detector.