Abstract: An electrode plate (20) for storage batteries is immersed into an aqueous solution (18) containing phosphoric acid, an ethoxy alcohol, ammonium bifluoride, sulfonic acid and sodium xylenesulfonate, and the aqueous solution (18) is stirred by a screw stirrer (22). The aqueous solution (18) is kept at about 30° C. by a heater (14), and the active material of the electrode (20) is separated therefrom. The aqueous solution (18) contains the respective solutes in the following mass ratios: 15-20 parts by mass of the phosphoric acid; 3-7 parts by mass of the ethoxy alcohol; 2-6 parts by mass of the ammonium bifluoride; 4-8 parts by mass of the sulfonic acid; and 1-3 parts by mass of the sodium xylenesulfonate.

Abstract: An electrode plate (20) for storage batteries is immersed into an aqueous solution (18) containing phosphoric acid, an ethoxy alcohol, ammonium bifluoride, sulfonic acid and sodium xylenesulfonate, and the aqueous solution (18) is stirred by a screw stirrer (22). The aqueous solution (18) is kept at about 30° C. by a heater (14), and the active material of the electrode (20) is separated therefrom. The aqueous solution (18) contains the respective solutes in the following mass ratios: 15-20 parts by mass of the phosphoric acid; 3-7 parts by mass of the ethoxy alcohol; 2-6 parts by mass of the ammonium bifluoride; 4-8 parts by mass of the sulfonic acid; and 1-3 parts by mass of the sodium xylenesulfonate.