Regeneration of Waste Ferric Chloride Etchant Using HCl and $H_2O_2$

HCl과 $H_2O_2$를 이용한 폐 $FeCl_3$ 에칭액의 재생

  • Lee, Hoyeon (Department of Chemical Engineering, Inha University) ;
  • Ahn, Eunsaem (Department of Chemical Engineering, Inha University) ;
  • Park, Changhyun (Department of Chemical Engineering, Inha University) ;
  • Tak, Yongsug (Department of Chemical Engineering, Inha University)
  • 이호연 (인하대학교 공과대학 화학공학과) ;
  • 안은샘 (인하대학교 공과대학 화학공학과) ;
  • 박창현 (인하대학교 공과대학 화학공학과) ;
  • 탁용석 (인하대학교 공과대학 화학공학과)
  • Published : 2013.02.10

Abstract

$FeCl_3$ has been used as an etchant for metal etching such as Fe, Cu, and Al. In the process of metal etching, $Fe^{3+}$ is reducted to $Fe^{2+}$ and the etching rate becomes slow and etching efficiency decreased. Waste $FeCl_3$ etchant needs to be regenerated because of its toxicity and treatment cost. In this work, HCl was initially mixed with the waste $FeCl_3$ and then, strong oxidants, such as $O_2$ and $H_2O_2$, were added into the mixed solution to regenerate the waste etchant. During successive etching and regeneration processes, oxygen-reduction potential (ORP) was continuously measured and the relationship between ORP and etching capability was investigated. Regenerated etchant using a two vol% HCl of the total etchant volume and a very small amount of $H_2O_2$ was very effective in recovering etching capability. During the etching-regeneration process, the same oxygen-reduction potential variation cannot be repeated every cycle since concentrations of $Fe^{2+}$ and $Fe^{3+}$ ions were continuously changed. It suggested that the control of etching-regeneration process based on the etching time becomes more efficient than that of the process based on oxygen reduction potential changes.

Keywords

ferric chloride;hydrogen peroxide;Fenton reaction;etching;regeneration

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