发明名称 |
Method of regenerating an ammoniacal etching solution |
摘要 |
In addition to catalyzing the reoxidization of spent alkaline etching agent, the suspension of activated carbon powder in the etching solution also increases the speed of etching when the etching solution is recirculated in the etching of printed circuit boards. The ammonium sulfate etching solution is set to a pH of about 9 by the addition of ammonia gas. In the recirculation of the etching solution, a part of the solution can be freed by filtration from suspended carbon particles and passed through the cathode and anode chambers of an electrolysis cell for the recovery of the etched metal by deposition on the cathode. The activated carbon powder for this purpose is calcined before use, at a temperature of between 900 DEG and 1200 DEG C. in vacuum or in an atmosphere that is inert, reducing, or only slightly oxidizing as in the case of an atmosphere containing carbon dioxide, water vapor or both, in a concentration that does not appreciably oxidize the carbon particles.
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申请公布号 |
US4385969(A) |
申请公布日期 |
1983.05.31 |
申请号 |
US19810287492 |
申请日期 |
1981.07.27 |
申请人 |
KERNFORSCHUNGSANLAGE JUELICH GESELLASCHAFT MIT BESCHRAENKTER HAFTUNG;ELO-CHEM ATZTECHNIK GMBH |
发明人 |
KASTENING, BERTEL;FAUL, WOLFGANG;FUERST, LEANDER;HOLZER, WALTER |
分类号 |
C23F1/40;C23F1/46;H05K3/06;(IPC1-7):C25C1/12;C25C1/00;C25C1/16 |
主分类号 |
C23F1/40 |
代理机构 |
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代理人 |
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主权项 |
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地址 |
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