Method for preparing fine copper powder by recovering PCB alkaline etching waste liquid

The invention discloses a method for preparing fine copper powder by recovering PCB (printed circuit board) alkaline etching waste liquid, which comprises the following steps: under the condition of an ultrasonic field, adding a proper amount of sodium hydroxide into the PCB alkaline etching waste liquid to adjust the pH value of the solution, adding a certain mass of glucose to carry out pre-reduction reaction, then adding PVP (polyvinylpyrrolidone) and thiourea dioxide to carry out reduction reaction, and finally preparing the fine copper powder. Cuprous oxide generated by the pre-reduction effect is reduced into elementary copper, and fine copper powder is obtained. According to the method, an ultrasonic-assisted two-step liquid phase reduction method is adopted, valuable metal copper is recycled from the PCB alkaline etching waste liquid, and resource recycling and recycling of the etching waste liquid are achieved. Compared with the prior art, the method has the advantages of simple process, short reacti