scholarly journals Recycling of Spent Hydrodehalogenation Catalysts – Problems Dealing with Separation of Aluminium

2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Tomáš WEIDLICH ◽  
Barbora KAMENICKÁ
Keyword(s):  
Aqueous Solution ◽  
Printed Circuit Boards ◽  
Metal Salt ◽  
Volatile Components ◽  
Circuit Boards ◽  
Brominated Flame Retardant ◽  
Printed Circuit ◽  
Reductive Degradation ◽  
Zn Alloys

Our study is focused on utilization and recycling of copper and nickel applicable for reductive degradation of tetrabromobisphenolA (TBBPA), the high use brominated flame retardant for printed circuit boards. Deactivated and/or poisoned hydrodebrominationcatalysts are produced by reductive destruction of brominated phenol (TBBPA) dissolved in alkaline aqueous solution using RaneyAl-Ni and/or Devarda´s Al-Cu-Zn alloys. Spent metallic slurry is treated with aqueous sulfuric acid to dissolve residual aluminiumand/or zinc and decanted residual metal is subsequently treated under oxidation conditions and dissolved in excess of mineralacid by co-action of oxidant. The corresponding metal salt is separated from corresponding leachates containing excess of acid byevaporation and recycling of volatile components. Obtained copper or nickel salts were used as sources of Raney type hydrodebrominationcatalysts produced for in-situ by action of NaBH4.

Polymerization of poly-(amic acid) ammonium salt in aqueous solution and its use in flexible printed circuit boards

2017 ◽  
Vol 96 ◽  
pp. 393-402 ◽  
Author(s):  
Zhibo Cao ◽  
Xiaogang Zhao ◽  
Daming Wang ◽  
Chunhai Chen ◽  
Chunyan Qu ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Ammonium Salt ◽  
Printed Circuit Boards ◽  
Amic Acid ◽  
Circuit Boards ◽  
Printed Circuit ◽  
Flexible Printed Circuit

In-Situ Thermal Chamber 3D X-Ray Computed Tomography for Non-Destructive Detection of Submicron Via-Crack in Printed Circuit Boards

2020 ◽  
Author(s):  
Daechul Choi ◽  
Sooyoung Ji ◽  
Jaelim Choi ◽  
Miyang Kim ◽  
Eunju Yang ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Printed Circuit Boards ◽  
Fault Isolation ◽  
Circuit Boards ◽  
X Ray ◽  
Printed Circuit ◽  
Thermal Chamber ◽  
X Ray Computed ◽  
Non Destructive

Abstract In this paper, we demonstrate a case for non-destructive detection of submicron wide via-crack in printed circuit boards (PCBs) by using in-situ thermal chamber 3D x-ray computed tomography. The defect location is verified by a PFA (Physical Failure Analysis), and good agreement was made. This fault isolation method is proposed as a possible solution for identifying submicron cracks in PCB substrates during challenging investigations.

A Novel Wet Etch In-situ Decapsulation of Devices on Boards

2010 ◽  
Author(s):  
Michael A. Gonzales ◽  
Joanna Kiljan
Keyword(s):  
Integrated Circuits ◽  
Printed Circuit Boards ◽  
Region Of Interest ◽  
Temperature Sensitive ◽  
Circuit Boards ◽  
Endpoint Detection ◽  
Printed Circuit ◽  
Novel Technique ◽  
Wet Etch

Abstract This paper presents a novel technique for decapsulation of integrated circuits (ICs) mounted on printed circuit boards. This technique overcomes wet etch related sidewall blowouts that damage or alter the performance of the IC and board under test. It also allows well defined etch geometries and better endpoint detection. This is accomplished by protecting the region of interest (ROI) with a fast-curing, acid-resistant maskant that peels off easily. The technique was successfully utilized on a densely populated board, which exhibited temperature sensitive failure mechanism, as discussed in this paper.

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