| abstract |
A method of purifying, in which calcium and barium are removed from a copper salt solution, such as a copper chloride etchant waste occurring after etching with a cupric chloride solution, to thereby attain purification; a relevant purification apparatus; and a copper chloride solution purified by the purification method. In particular, there is provided a method comprising neutralizing a copper salt solution, such as a copper chloride etchant waste, with an alkali, such as sodium hydroxide, so that, for example, the pH value falls within the range of 3.5 to 7.0 (step S1); subjecting the obtained solid-liquid mixture to solid-liquid separation (step S2); and re-dissolving the solid contents obtained by the solid-liquid separation in an inorganic acid, such as hydrochloric acid (step S3), thereby obtaining a copper chloride solution having calcium and other impurities removed therefrom. |