RECYCLING ELECTROCHEMICAL MACHINING FOR METAL RECOVERY AND WASTE ELIMINATION Brian T. Skinn Faraday Technology, Inc. MSEC2014-4048 Co-Authors Savidra C. Lucatero, Stephen T. Snyder , E. Jennings Taylor Timothy D. Hall, Maria Inman
June 13, 2014
[email protected]
Outline • Electrochemistry Overview – Conventional vs. Pulse/Pulse-Reverse (P/PR)
• Recycling Electrochemical Machining – ECM: Problem & Opportunity – (R)ECM Concept & System Design – Results to Date
2
MSEC 2014 - B Skinn - 13 Jun 2014
Electrochemical Processing
Conventional vs Pulse/Pulse-Reverse
Electrochemistry Red ⇋ n e – + Ox Electronic Current + Anode
– Cathode
Ionic Current
Current is net flow of POSITIVE CHARGE
4
MSEC 2014 - B Skinn - 13 Jun 2014
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
5
MSEC 2014 - B Skinn - 13 Jun 2014
Electrochemistry Red ⇋ n e – + Ox Electronic Current + Anode
e–
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
Water Electrolysis Anodic / Cathodic H2 production Bubble generation
Current is net flow of POSITIVE CHARGE
6
MSEC 2014 - B Skinn - 13 Jun 2014
Pulsed Waveforms vs DC Know:
Linearized Concentration Profile C
DC Nernst Diffusion Layer Model
(-)
Cb
Cb
Time x
(+)
X=0
Distance from electrode
7
MSEC 2014 - B Skinn - 13 Jun 2014
Pulsed Waveforms vs DC Know:
Linearized Concentration Profile C
Nernst Diffusion Layer Model
(-)
Cb
Cb
Time x
(+)
X=0
Distance from electrode
8
Pulsed Waveforms vs DC Know:
Linearized Concentration Profile C
Nernst Diffusion Layer Model
(-)
Cb
Cb
Time x
X=0
(+)
Distance from electrode
Cx,t
Boundary Layer Cb t1 < t2
< t3
