Method for extracting germanium from germanium-containing smoke dust

The invention relates to a method for extracting germanium from germanium-containing smoke dust, and belongs to the technical field of chemical metallurgy. The method adopts the germanium-containing smoke dust, which is obtained by dry distillation of lignite and has the germanium content of 8.0-30.0wt%, as a raw material to perform extraction, and comprises the following steps: performing leaching distillation on the germanium-containing smoke dust; cooling the obtained gas containing germanium tetrachloride to obtain a crude germanium tetrachloride solution; performing first-time extraction on the crude germanium tetrachloride solution; filtering the germanium tetrachloride solution obtained by the first-time extraction by using a separating column; performing second-time filtration on the obtained germanium tetrachloride solution to obtain a refined germanium tetrachloride solution; and hydrolyzing the obtained refined germanium tetrachloride solution into germanium dioxide, and reducing the germanium dioxide to obtain germanium. According to the method provided by the invention, the technological process is easy to control and strong in operability, the germanium recovery rate is stable, the cost is significantly reduced relative to that of a continuous distillation or continuous extraction process, the purity of germanium can reach more than 99.999%, and the resistivity of germanium is more than 15 ohm cm.