PURPOSE: To efficiently and inexpensively produce highly pure cuprous chloride by adding a reducing agent to a cupric chloridecontaining solution high in the concentrations of copper and hydrochloric acid, filtering off impurities from the obtained chloro complex solution, and subsequently cooling the filtrate.
CONSTITUTION: For example, a cupric chloride etching waste solution is concentrated into a solution having a copper concentration of 11wt.% and above and a hydrochloric acid concentration of ≥9wt.%. The cupric chloride-containing solution is mixed with a reducing agent such as iron or copper to reduce the cupric chloride into cuprous chloride. The cuprous chloride forms a chloro complex and is dissolved to provide a chloro complex solution. Impurities are filtered off from the chloro complex solution. The chloro complex solution is cooled at e.g. approximately 20°C to deposit the cuprous chloride from the solution by the utilization of the difference between the solubilities due to the difference of temperatures, followed by filtering out the cuprous chloride, thus recovering the crystals of the highly pure cuprous chloride.
AWAYA MASARU
SUZUKI MICHIMASA
HIRAHARA BUNJI
