RECYCLING ELECTROCHEMICAL MACHINING FOR METAL RECOVERY AND ELIMINATION OF WASTE Brian T. Skinn Faraday Technology, Inc. 227th Meeting of the Electrochemical Society Chicago, IL
Co-Authors Savidra C. Lucatero, Stephen T. Snyder , E. Jennings Taylor Timothy D. Hall, Heather A. McCrabb, Holly G. Garich, Maria Inman
May 26, 2015
[email protected]
Outline • Applied Electrochemistry – Scope – Conventional vs. Pulse/Pulse-Reverse (P/PR)
• Recycling Electrochemical Machining – ECM: Problem & Opportunity – (R)ECM Concept & System Design – Results to Date
2
227th ECS - B Skinn - 26 May 2015
Applied Electrochemistry Red ⇋ n e – + Ox Electronic Current + Anode
– Cathode
Ionic Current
Current is net flow of POSITIVE CHARGE
3
227th ECS - B Skinn - 26 May 2015
Applied Electrochemistry Red ⇋ n e – + Ox Electronic Current
e– +
Anode Reactions
–
M0 n e – + Mn+ Anode
Cathode
S n e – + Sn+
Ionic Current
2 H2O 4 e – + 4 H+ + O2
Current is net flow of POSITIVE CHARGE
4
227th ECS - B Skinn - 26 May 2015
Applied Electrochemistry Red ⇋ n e – + Ox Electronic Current
e– + Anode
Anode Reactions
Material Processing Anodic (subtractive) Electropolishing
–
M0 n e – + Mn+
Cathodic (additive) Electroplating
S n e – + Sn+
Solute Modification Anodic / Cathodic Chlor-alkali
Cathode
Ionic Current
2 H2O 4 e – + 4 H+ + O2
Current is net flow of POSITIVE CHARGE
5
Water Electrolysis Anodic / Cathodic H2 production Bubble generation
227th ECS - B Skinn - 26 May 2015
Pulsed Waveforms vs DC Know:
Linearized Concentration Profile C
DC Nernst Diffusion Layer Model
(-)
Cb
Cb
Time x
(+)
X=0
δ
Distance from electrode
6
227th ECS - B Skinn - 26 May 2015
Pulsed Waveforms vs DC Know:
Linearized Concentration Profile C
PC DC Nernst Diffusion Layer Model
(-)
Cb
Cb
Time x
(+)
X=0
δ
Distance from electrode
7
227th ECS - B Skinn - 26 May 2015
Pulsed Waveforms vs DC Know:
Linearized Concentration Profile C
PC DC Nernst Diffusion Layer Model
(-)
Cb
Cb
Time x
δ
X=0
(+)
Distance from electrode
Cx,t
Boundary Layer Cb t1
< t2
< t3
τ
