| 摘要 |
PURPOSE:To return the etching soln. to be used cyclically for metallic iron-Ni based plates to the original state having etching power by separating and regenerating the Ni compsn. having no etching power formed in the etching soln. CONSTITUTION:An original mask plate enters an etching chamber 1 where the plate is perforated with aperture holes by an etching soln. consisting of FeCl3. The etching soln. is pumped P1 from a tank 4 into the chamber 1 and is ejected from a manihold 2, then the soln. returns into the tank 4. Lines 6-8 for feeding gaseous chlorine which is a regeneration agent, water and HCl are provided to the circulating system of the etching soln. A specified volume of the soln. from the tank 4 is pumped P2 to a regenerative circulating system, where aq. NH4OH is added thereto in a reaction tank 10 to modify the Fe<2+>- and Fe<3+>-contg. compsn. to the precipitate of iron hydroxide. The Ni<2+>-contg. compsn. remains in the form of complex salt in the soln. in this state and is separated by a filter 12. The filtrate is discarded. The separated precipitate is transferred into a dissolving tank 13, where a hydrochloric acid is fed to the precipitate to convert the same to iron chloride. Water is added thereto in an adjusting tank 16 and the compsn. is returned to the tank 4. |
