| 摘要 |
PURPOSE:To reduce the quantity of etchant used, and to contrive facilitation of both the control of density of an electrolyte and the control of processes by a method wherein an etching electrolyte mainly composed of hydrochloride acid is continuously fed to the electrolyte vessel used in the former stage and the electrolyte used in the vessel used in the former stage is mainly used in the etching electrolyte for the electrolyte vessel used in the latter stage. CONSTITUTION:Three electrolytic vessels, namely, a first electrolytic vessel 1, a second electrolytic vessel 2 and a third electrolytic vessel 3, are provided, and an electrolyte mainly composed of hydrochloric acid is supplied to the first electrolytic vessel 1 continuously. The electrolyte used in the first electrolytic vessel 1 is fed to the second electrolytic vessel 2, and then the electrolyte used in the second electrolytic vessel 2 is supplied to the third electrolytic vessel 3. At this time, if the hydrochloric acid of 20% or higher in concentration, desirably 30 to 100%, is added to the electrolytic vessel used in the latter stage, the improvement in electrostatic capacitance of etched foil and reduction in quantity of waste liquid can be expected. Also, the quantity of etchant used can be reduced while the electrostatic capacitance is being maintained, and the control of concentration of the electrolyte and the control of process can also be facilitated. |
