a lead monoxide precursor of high surface-area for lead-acid battery paste
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A Lead Monoxide Precursor of High Surface-Area for Lead-Acid Battery Paste. R Vasant Kumar Department of Materials Science University of Cambridge, UK. Acknowledgements. - PowerPoint PPT PresentationTRANSCRIPT
A Lead Monoxide Precursor of High Surface-Area for Lead-Acid Battery Paste
R Vasant Kumar
Department of Materials Science
University of Cambridge, UK
Acknowledgements
Seref Sonmez, Vega Kotzeva, Jiakuan Yang, Lilia Sanchez, Richard Darby, Yingjun Liu, David Zou, of Department of Materials Science
Lei Wang, Nigel Williams of the Business School
Maggie Wilkinson & Zlatka Stoeva of Cambridge Enterprise
A Schematic Cut-Away of Lead Battery
Table 1 Range of Compositions from a dry lead battery paste
Material Wt %
Lead sulphate 55-65
Lead dioxide 15-40
Lead monoxide 5-25
Metallic lead 1-5
Carbon black, plastics, fibres, other sulphates
1-4
Current Method - Pyrometallurgy
*For 10,000 tpy plantCapital: $4-5MEnergy: 14,000MWH*Independent Consultants
Battery Manufacture
Lead is then chemically oxidised to PbO for the battery industry
PbO is electrochemically reduced to Pb and oxidised to PbO2 to make anode and cathode
Lead containing Organic
Crystalline Compounds
PbO Precursor
New
A new process for recycling lead battery waste
→
↓↑
→
Special Leaching/Crystallization Process
Lead Battery
Combustion/Calcination Process
Manufacturing Lead Battery
Waste Battery
Paste
New Paste
Patent: PCT/GB2007/004222; WO2008/056125RV Kumar, S Sonmez and V Kotzeva
A new process for recycling lead battery waste
→
Paste
Pb GridHeat Energy from pasterecycling
New Grid
New Paste directly from paste recycling
Kettle
Waste Battery
New lead Battery
Green PB Recycling Process
Patent: PCT/GB2007/004222; WO2008/056125RV Kumar, S Sonmez, V Kotzeva
Leaching
Combustion-Calcination
SpentLead grid
MetallicLead
Energy
0
1
2
3
4
5
6
0 10 20 30 40 50 60
Time / mins
Tem
pera
ture
Ris
e / °
C
1.5 : 1 1.25 : 1 1 : 1
Leaching of battery paste PbO and PbO2
Ratio ofPaste/reagent
10
20
30
40
50
0 5 10 15 20 25 30 35 40 45 50 55 60 65
Reaction time(min)
Tem
pera
ture
(℃
) Lead (II) oxide
Lead (IV) dioxide
Lead sulfate
1
1.5
2
2.5
3
3.5
4
4.5
0 10 20 30 40 50 60
Time / mins
pH
1.5 : 1 1.25 : 1 1 : 1
pH vs time for varying paste/reagent ratio
5 15 25 35 45 55 65
2 θ(degree)
Inte
nsi
ty(a
.u.) A
B
C
D
XRD Pattern of A: Standard Lead citrate; B: from PbO; C: fromPbO2 and D: from PbSO4
Lead organic crystallites of Lead citrate (A) from PbO and PbO2
SEM images of Lead Citrate (B) from PbSO4
Precursors Ideal weight loss
Fromdehydrating
weight loss
(TGA)
Ideal weight loss
For decomposition to PbO
weight loss
after exothermic peak of TGA
weight loss
calcined at 350 for ℃1h
Precursor I[Pb(C6H6O7)]·H2O 4.3% 4.20% 46.3% 49.8% 48.2%
Precursor II[Pb(C6H6O7)]·H2O 4.3% 4.20% 46.3% 49.8% 49.0%
Precursor III[Pb3(C6H6O7)2]·3H2O
5.1% 5.50% 36.6% 38.3% 37.5%
Combustion-Calcination of Lead citrates in Air
334.01°C
2000J/g
167.76°C
151.79°C238.7J/g
285.09°C
-5
0
5
10
15
20
25
He
at
Flo
w (W
/g)
0
20
40
60
80
100
120
We
igh
t (%)
40 80 120 160 200 240 280 320 360 400
Temperature (°C)
Sample: 20070423PbO-airSize: 7.8140 mgMethod: Ramp
DSC-TGAFile: C:...\yj231\20070423\20070423PbO-air.002Operator: yj231Run Date: 23-Apr-2007 14:50Instrument: SDT Q600 V8.2 Build 100
Exo Up Universal V4.3A TA Instruments
Wt loss and heat produced on decomposing Pb citrate (A)
357.91°C2427J/g
117.77°C
284.16°C
9.869%
-5
0
5
10
15
20
25
He
at
Flo
w (W
/g)
0
20
40
60
80
100
120
We
igh
t (%)
40 80 120 160 200 240 280 320 360 400
Temperature (°C)
Sample: 20070411PbSO4airSize: 15.9840 mgMethod: Ramp
DSC-TGAFile: C:...\DSC\20070411-PbSO4air-analysis.001Operator: rs489Run Date: 11-Apr-2007 14:27Instrument: SDT Q600 V8.2 Build 100
Exo Up Universal V4.3A TA Instruments
Wt loss and heat produced from lead citrate (B)
10 20 30 40 50 60 70 80 90
2 θ(degree)
Inte
nsity
(a.u
.)
300℃
350℃
400℃
450℃
Pb
PbO
Mixture of α and β PbO and metallic Pb – can be controlledto varying ratios
Heat Produced
Combustion-calcination of lead citrates can generate thermal energy of 2 kJ/ g of lead battery paste
The Raceway Adiabatic Flame Temperature is over 1500K!
This energy is equivalent to 550 kWh/kg of paste!
PbO morphology after combustion-calcination
SEM
TEM
Spongy PbO Agglomerated PbO
Skeletal PbO
Additives during leaching to control PbO morphology
Lead citrate PbO
Addition of C-fibre to PbO precursor
FEGSEM – Each fibre is coated FEGSEM – Each fibre is coated with PbOwith PbO
Physical Properties of PbO
Free Pb: 0 to 20 % Crystal structure: α/β ratio: 0.05 to 1 Crystal size: 20 – 100 nm Particle average size: 1 – 5 μm Specific surface area (BET) m2/g: 2.4 to 5.5 Acid absorption (mg H2SO4/ g oxide): 270 –
530
Preliminary Electrochemical Testing
First discharge capacity in the 130 – 160 mAh/g of PbO
Increase in discharge capacity with no of cycles up to 8-10 cycles and then remained constant to 50 cycles
Further work is ongoing
-5.0 -2.5 0 2.5-0.10
-0.05
0
0.05
0.10
E (Volts)
I (A
mps/
cm2 )
A
BC
DE
A: PbO /PbSO4 reduction to PbB: Pb oxidation to PbSO4
C: PbSO4 oxidation to PbO2
D: PbO2 reduction to PbSO4
E: PbSO4 reduction to Pb
The Green PB Process
For 10,000 tpy plantCapital: $1-1.5 MEnergy: 1750 MWH
5000 MWhEnergy available
Conclusions
New method for directly recovering PbO from spent battery paste
Many control variables available to vary physical properties of PbO product
Promising preliminary results Thank You