“ARD REMEDIATION WITH SLAG: AN APPLICATION TO BERKELEY PITLAKE WATER” Courtney A. Young Dept Head and Lewis S. Prater Professor Metallurgical & Materials Engineering Montana Tech Butte MT 59701 Denver, CO April 3-5, 2012 Monitoring and Treatment Session 8
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“ARD REMEDIATION WITH SLAG: AN APPLICATION
TO BERKELEY PITLAKE WATER”
Courtney A. Young
Dept Head and Lewis S. Prater Professor
Metallurgical & Materials Engineering
Montana Tech
Butte MT 59701
Denver, CO April 3-5, 2012 Monitoring and Treatment Session 8
Dick Berg, State Geologist, MBMG
Montana Tech, Butte MT
Larry Twidwell, Professor Emeritus, M&ME
Montana Tech, Butte MT
Krag Filius, Project Engineer
MSE Technology, Butte MT
Eric Streich, Process Engineer
Holcim Cement, Trident MT
• Berkeley Pitlake
• Previous Research
• Silicate Slags
• Objectives
• Procedures
• Results & Discussions
• Conclusions
• Acknowledgements
• Berkeley Pitlake
• Previous Research
• Silicate Slags
• Objectives
• Procedures
• Results & Discussions
• Conclusions
• Acknowledgements
Continental Pit
– Treatment Plant
– Horseshoe Bend Water
– MR Concentrator
Butte – Viewing Stand
Interstate 15/90 –
Walkerville –
1880 - Butte was an early copper-mining town:
- Referred to as “The Richest Hill on Earth”
- One of the world’s largest sulfide ore deposits
1920 - ACC controlled most mines
1955 - ACC began phasing out underground mining
1977 - ARCO purchased all operations
1982 - Operations halted and pumps turned off
1983 - Water first appeared in the pit
- Listed as a Superfund site
- Part of the largest mining Superfund site
Berkeley Pitlake Water: - encompasses ~700 acres - is ~1,000 feet deep - contains ~40 billion gallons - fills at 2.6 million gallons per day - will reach “critical level” in 2023
SO4 (7500 ppm) Fe (1000 ppm) Zn (650 ppm) Al (300 ppm) Mn (250 ppm) Cu (200 ppm) Cd (2.5 ppm) As (0.5 ppm)
Berkeley Pitlake Water: - is acidic near pH 2.5 - contains metals at high concentrations (99% Water):
Participate in a “series” of 5 studies to summarize available information Generate new information to formulate conceptual environmental models for the Berkeley Pitlake from all of its features Provide data for the development of advanced treatment technologies
243.5 566.3 2.3 151.2 214.2 5.9 1019.8 Initial BPL Water
Al Zn Cd Cu Mn As Fe
0.2 5 0.005 1.3 0.05 0.05 0.3 Drinking Standard
Stage 1A: H2O2 = 2OH
; Fe2+ + OH
= Fe3+ + OH-; Fe3+ + 3OH
- = Fe(OH)3
Stage 1B: 3Mn2+ + 2MnO4
- + 2H2O = 5MnO2 + 4H+
Stage 2: Cu2+ + S2- = CuS
Stage 3: Cd2+ + S2- = CdS; Zn2+ + S2- = ZnS
Stage 4: Al3+ + 3OH- = Al(OH)3
G a s
G l a s s F r i t
U V S o u r c e
M a g n e t i c S t i r r e r
E l e c t r o d e
M a g n e t
Fe/Mn/As Precipitation
Cu Precipitation
Zn/Cd Precipitation
Al Precipitation
SO Remediation
Berkeley PitlakeWater
2 2
H S
H S
NaOH
UV/H O /NaOH
2
2
Vacuum
Na, K, Mg, Ca Solution
To Softening and Discharge
?
• Selective metal recovery is possible • A 7-stage process has been envisioned and shown to work (in batch mode) • Fe, As, Cu and Cd met DWS • Al almost met DWS • Mn and Zn did not meet DWS • KMnO4 addition needs to be precise • Zn may have precipitated amorphously • SO4 removal was not done but options are Freeze Crystallization Reverse Osmosis Gypsum Precipitation SRB Bioreduction Chemoreduction Photoreduction Reductive Precipitation • Softening to remove Na, K, Mg and Ca
0 5 1 0 1 5 2 0 2 5 3 0 3 5
D e p t h ( m )
2 . 2 0
2 . 2 5
2 . 3 0
2 . 3 5
2 . 4 0
2 . 4 5
2 . 5 0
p H
0 . 0
0 . 5
1 . 0
1 . 5
2 . 0
2 . 5
3 . 0
3 . 5
4 . 0
4 . 5
D i s s o
l v e d
O x y
g e n
( m g / l )
3 0 0
3 5 0
4 0 0
4 5 0
5 0 0
5 5 0
6 0 0
6 5 0
E ( m
V )
6
8
1 0
1 2
1 4
1 6
1 8
2 0
2 2
2 4
T e m
p e r a t u r e ( C )
p H
H
E H
D O
T e m p
B e r k e l e y P i t l a k e S e p t . 5 , 1 9 9 1
o
-1.0
-0.5
0
0.5
1.0
1.5
0 2 4 6 8
pH
Fe(SO 4 ) +
Fe(
SO
4 ) 2
-
Fe 2+
FeSO 4 ( aq )
Fe
Fe 8 O 8 (OH) 6 SO 4 . 5H 2 O
(HSO 4 - ) (SO
4 2- )
(HS - ) {H 2 S( aq )}
E H
(V
olt
s)
*
Profiles indicated chemoclines/thermoclines existed and were successfully reproduced in lab
They have been explained by, but can not be totally attributed to
HSBW being less dense than BPLW so, when it enters the pitlake, it floats on top rather than mixes in, and
Biological activity which should increase DO as well as pH
Experiments showed that the interaction of sunlight (UV radiation) and air with BPL water plays a significant role
(Deep Water, Pore Water and Sediment)
Collect Core Sample Split & Section the Core Siphon/Filter Off
Deep/Pore Water
Analyze the Water
& Solid Contents
(Deep Water, Pore Water and Sediment)
zzz
zzzzzzz
wwwwwwwwvvv
Ferric Iron Solubility in Pore WaterSchwertzmannite
Fe8O8(OH)6SO4
0.001
0.01
0.1
1
10
100
Fe
3,p
pm
0 1 2 3 4 5
pH
x x x x x x
z z z z z z z z z
z w w
w w w w w w v
v v
Potassium Solubility Jarosite
A KFe 3 (SO 4 ) 2 (OH) 6 B KAl 2 AlSi 3 O 10 (OH) 2
A A + B
A A + B
0.001
0.1
10
1000
0 1 2 3 4 5
pH
Surface Water (pH ~ 2.5)
Deep Water (pH ~ 3.3)
Concentrations are controlled by the solubility of identified minerals and precipitates!
A = Fe/Si Ratio (0-2); B = Size (um); C = Amount (g/L)
Size = 37 μm Size = 147 μm
Design-Expert® Software
pH 10.05
4.57
X1 = A: Fe/Si Ratio X2 = C: Amount, g/L
Actual Factor B: Size, um = 37
0.0 0.5 1.0 1.5 2.0
200
350
500
650
800 pH
A: Fe/Si Ratio
C: A
mo
un
t, g
/L
5.5 6.0 7.0
7.5
9.0
5.0
6.5 8.0
8.5
9.5
Size = 92 μm
0 0.5
1 1.5
2
200 350
500 650
800
0
650
1300
1950
2600
Fe
(p
pm
)
Fe/Si Ratio
Amount (g/L)
Design-Expert® Software
Original Scale
Log10(Fe, ug/L)
974000
13.7
X1 = A: Fe/Si Ratio
X2 = C: Amount, g/L
Actual Factor
B: Size, um = 37
0.0 0.5 1.0 1.5 2.0
200
350
500
650
800
Fe, ug/L
A: Fe/Si Ratio
C: A
mount, g/L
300 1000100 10000
0
0.5
1 1.5
2
200 350
500 650
800
0.0
42.5
85.0
127.5
170.0
As (ppb)
Conc (g/L)
0
0.5
1
1.5
2
200 350
500 650
800
0
650
1300
1950
2600
Fe (ppm)
Fe/Si Ratio Conc (g/L)
Fe/Si Ratio
0 0.5
1 1.5
2 200
350
500
650
800
0
300
600
900
1200
Zn (ppm)
Fe/Si Ratio Conc (g/L)
0 0.5
1 1.5
2
200
350
500
650
800
0
700
1400
2100
2800
Cd (ppb)
Fe/Si Ratio Conc (g/L)
a) b)
c) d)
Berkeley Pitlake
Previous Research
Silicate Slags
Objectives
Procedures
Results & Discussions
• Conclusions
• Acknowledgements
Slags can be an effective for remediating ARD
Their use could or will: replace lime (pseudowollastonite slag) diminish lime consumption (fayalite/olivine) lead to remediation of two ecosystems
Depending on the slag type and particle size: effluent pH from 5-9 can result effluent concentrations can meet DWS
Al and Cu concentration profiles are similar to Fe
Likewise, Al and Cu redissolution at high pH is minimal similar to Fe
Berkeley Pitlake
Previous Research
Silicate Slags
Objectives
Procedures
Results & Discussions
Conclusions
• Acknowledgements
This research was previously funded by the MWTP via an Interagency Agreement (IAG) between the U.S. EPA and the U.S. DoE, IAG No. DW89935117-01-0.
Thanks are also extended to the Department of Metallurgical & Materials Engineering at Montana Tech for bearing the costs for some analyses and the MBMG for helping collect samples: James Madison and Ted Duaime.
Sincere appreciation is given to the workforce who have worked on these projects over the years. MS students included Ray Ziolkowski, Tom McMillan, Yu Chuan Tai, Eric Streich and Krag Filius. BS students include Sonny Adams, Jennifer Gambill and Brian Ross.
We are always on the lookout for funding Series VI to !
Berkeley Pitlake
Previous Research
Silicate Slags
Objectives
Procedures
Results & Discussions
Conclusions
Acknowledgements
U.S. EPA Hardrock Mining Conference (Advancing Solutions for a New Legacy)