1. Functionalized Silica Polyamine Composites for Metal Recovery from
Hazardous Mining Wastewater and Acid Leach Solutions Acknowledgments
• Dr. Bob Fischer
• Dr. Johnnie Moore
Dr. Ed Rosenberg (Chemistry) Toxic and polluting metals contaminate waters worldwide. The reported materials exhibit exceptional metal
• Carolyn Hart
selectivity and capacity at high flowrates. Functionalized silica polyamine composites were utilized to recover
Dan Nielsen (Ph.D. Student – Chemistry) copper(II), zinc(II) and manganese(II) from Berkeley Pit Lake water (Butte, MT). Additional composite materials • John Deming
Joel Clancey (Research Assistant) were used to separate five rare earth elements from an authentic acid leach matrix. Iron(III) was removed from • Montana Board of Research &
Purity Systems, Inc. Jeff McKenzie (Research Assistant) a synthetic copper(II) electrowinning solution. All reported process strategies allow for continuous high flow
treatment. Bench-scale studies show the potential for these materials to be used at an industrial-scale.
Commercialization Technology
• Department of Energy
In 2003 the U.S. Geological Survey had identified
over 230,000 abandoned hardrock mines in the
western U.S., 6,000 of these are located in pH Adjustment & Floculation Chamber
Montana state. 350 of Montana’s sites have been
Mixer
- Raise pH to 5.2 (using base)
- Add ~0.1% (by volume) floculant
determined to affect water quality designating
them as high priority sites. The Berkeley Pit (Butte,
MT) contains Cu(II), Zn(II), and Mn(II) pH
concentrations ideal for metal recovery using silica
Meter
C
u
composite technology. These three metals are
ubiquitous among mining waste sites as acid mine Z Holding
Pump
drainage (AMD), and their recovery offsets the cost
Settling n Tank M
Tank
n
of waste treatment. Multistage treatment begins by
the extraction of copper from the Berkeley Pit Lake
Pump
Pump
utilizing the picoline silica poly(allylamine) Pump
composite “CuWRAM.” Fe(III) and Al(III) are then
Filter Press
Recycle Filtrate
precipitated and removed as the metal hydroxides Depth (ft) Fe Zn Mg Ca Al Mn Cu Cd As
Treated Solution
0 270 378 430 512 195 179 86.8 1.84 <0.22
at pH 5.2. The acetate silica poly(ethyleneimine)
Berkeley Pit
50 892 578 538 494 281 212 145 2.39 0.34 Feed Reservoir Sludge toto Dump
Sludge Dump
composite “WP-2” is next used to concentrate and 500 986 580 536 494 281 209 177 2.43 0.78
purify zinc. Manganese is subsequently recovered
via “BP-2” (acetate silica poly(allylamine) Major Species Conc. (mg/L) of Berkeley
composite) in the sodium ion (base form). Abandoned Hardrock Mines in the Western U.S. Montana State’s High Priority Cleanup Sites The Berkeley Pit 1981 (top), 1999 (bottom) Pit Lake Water (at Various Depths) Diagram of Treatment Process
WP-2-CF Breakthrough Curve (4 CV 0.010 M NaOH to pH 1.9) BP-2-CF Breakthrough Curve
The target metals Cu(II), 0.50 CV/min., Feed pH = 2.2, 32 mg/g Cu(II) Capacity 600
0.50 CV/min., Feed pH = 5.3, 26 mg/g Zn(II) Capacity 0.50 CV/min., Feed pH = 4.9, 23 mg/g Mn(II) Capacity
Zn(II), and Mn(II) have been
700 800
700 Zn
Mn(II) Feed = 255 mg/L
selectively removed producing 600 Cu(II) Feed = 193 mg/L
500 Fe 600 700
Ca(II) Feed = 407 mg/L
Cu(II) Zn(II) Mn(II)
recovery solutions concentrated
Al Mg(II) Feed = 501 mg/L
Fe(III) Feed = 300 mg/L
600
500
Metal Conc. (mg/L)
Metal Conc. (mg/L)
500 Zn(II) Feed = 620 mg/L
Metal Conc. (mg/L)
400
Metal Conc. (mg/L)
Berkeley Pit (% purity) 5.0 18 6.0
10 - 50 fold, with high purity
Mn
Al(III) Feed = 253 mg/L
500
Mn(II) Feed = 248 mg/L
Zn(II) Feed = 602 mg/L 400
Recovery (% purity) 97 99.98 83 400
(83 - 99.98%). Molecular Mn(II) Feed = 172 mg/L
300 400
Berkeley Pit (g/L) 0.17 0.58 0.21
structures illustrate
300 300
300
200 H
Recovery (g/L) 10 6.5 9.0
rudimentary metal coordination 200 200 P O
N 200
- +
for clarity. Bench scale 100 100
100
O Na
100
treatment used 5.0 mL 0 O
O
Berkeley Pit Lake Metal Ion Recovery Data 0 50 100 150 200 250
0 0 Si N 0
columns, and data is reported Column Volume (CV = 5.0 mL)
2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5 0 20 40 60 80 100 120
O H H O
+
0 10 20 30 40 50 60 70 80 90 100
O Na
pH -
as a function of column
Column Volume (CV = 5.0 mL) O Column Volume (CV = 5.0 mL)
Si N N
WP-2-CF Strip Fractions
volume. CuWRAM was able to 0.50 CV/min., 9.0 N H2SO4, 97% Cu(II) Purity, 3% Fe(III) Berkeley Pit Precipitation/Filtration Study 10000
0.50 CV/min., 9 N H2SO4, 99.98% Zn(II) Purity O H
Mn2+ 0.50 CV/min., 9 N H2SO4, 83% Mn(II) Purity
O-
separate Cu(II) directly from 12000
9000 N
12000
Berkeley Pit Lake water in the H 10000 Cu(II) 32 mg/g 8000 Zn(II) 22 mg/g P H
O
10000 Mn(II) 30 mg/g
presence of Fe(III) and Al(III). H P O
N Fe(III) 1 mg/g
P P Ca(II) 4 mg/g
Metal Conc. (mg/L)
7000 Mn(II) 0 mg/g
Metal Conc. (mg/L)
Metal Conc. (mg/L)
H
Treated effluent from CuWRAM
8000 Al(III) 0.0 mg/g 8000 Mg(II) 2 mg/g
N HO N 6000
Zn(II) 0.0 mg/g N
was then adjusted to pH 5.2 O
O
Si N
H
N L = H2O, HSO4-, or SO42-
6000
Mn(II) 0.0 mg/g
N O 5000
Schematic Structure of BP-2 (base form) 6000
HO
and the produced Fe(III) and
P 4000
O
O H L L 4000 O 4000
Al(III) hydroxide precipitate O Si N O 3000
2+
Si N Cu H
O 2000
was removed by filtration. High
2000 - 2000
O H N N O N N O
