Transcript Diapositiva 1

National Polytechnic School
Extractive Metallurgy Department
Quito - Ecuador
VALORIZATION OF SOLID WASTE
RICH IN NICKEL AND VANADIUM
PRODUCED BY THE COMBUSTION OF FUEL OIL
Ibujés Paulina, De la Torre Ernesto and Guevara Alicia
The combustion of fuel oil in boilers
Fuel oil
Fly ash acumulation
Slag incrustation
The problem
Fly ash
Slag
Fly ash
methodology
Acid leaching
HNO3, HCl, H2SO4
25°C 24h 20 – 40 g/L
Crystallization
75 °C
solution
Roasting
250 – 950 °C
0.5 – 2.0 h
Characterization
Atomic Absorption Spectrophotometer
A X-ray diffraction (XRD) in a D8 advance equipment
Acid leaching
H2SO4
25°C 24h 20 – 200 g/L
cake
Stabilization
Cake
33-60 %
Cement 33-40 %
Lime
10-33 %
Fly ash characterization
by Atomic Absorption Spectrophotometer
Elements
Concentration (%)
Iron
5.42
Vanadium
5.31
Nickel
1.61
Calcium, sodium, potassium
< 1.00
Fixed carbon
85.00
Moisture
1.24
Volatile matter
0.86
Mineralogical content
by X-ray diffraction (XRD) equipment
fly ash roasted at 550 - 950°C
Mineral
Formula
Coulsonite
FeV2O5
Sodium vanadium oxide
Nickel vanadium oxide
Calcium vanadium oxide
Iron oxide
Iron hydroxide oxide
Grupo plagioclasa (albita, andesita, anortita)
NaV6O15 / Na0,33V2O5
NiV2O6
Ca0,17V2O5
Fe2O3
Fe1,833(OH)0,5 O2,5
(Na,Ca)Al(Si,Al)Si2O8
Karelianite
V2O3
Quartz
SiO2
Magnesiun Aluminium iron oxide
MgAl0,8Fe1,2 O4
Metal recovery in solution (%)
Vanadium, nickel and iron recovery
from stirred leaching (750rpm) with H2SO4 200 g/L and 25% solids on the fly ash
burned at 350°C for 1.5 hours.
100
90
80
70
60
50
40
30
20
10
0
0
2
4
6
8
10
12
14
16
18
20
Leaching time (h)
V
Ni
Fe
22
24
Crystallization of the strong solution
The strong solution produced
from stirred leaching (750rpm) with H2SO4 200 g/L and
25% solids on the fly ash burned at 350°C for 1.5 hours.
Mineral
Formula
Approximate
composition (%)
Iron sulfate
Fe2(SO4)3
60
Vanadium oxide
V2O5
27
Morenosite
NiSO4.7H2O
5
Jambornite
(Ni,Fe,Ca)(OH)2(OH,S,H2O)
4
Stabilization of cake
The cake produced
from stirred leaching (750rpm) with H2SO4 200 g/L and 25% solids
on the fly ash burned at 350°C for 1.5 hours
Mineral
Formula
Approximate
composition (%)
Carbon
C
90
Rhomboclase
HFe(SO4)2.4H2O
10
 The standard of public
38%
Cake
31%
Cement
31%
Lime
sewer system discharge
(Ecuador)
 U.S. EPA 40 CFR 261.24
standards, EPA 2003
Slag
Leaching
HNO3, HCl, H2SO4, HNO3+HCl,
NH3, NaOH, NaCl, NH4Cl, Na2CO3
Leaching H2SO4 + Br / H2O2
20-300 g/L
25-80°C
Roasting
2h
A scanning electron
microscope (MEB-EDX)
A X-ray diffraction (XRD) in
a D8 advance equipment
20-100 g/L
450-550°C
Roasting
NaCl, Na2CO3
Characterization
Atomic Absorption
Spectrophotometer
Leaching H2SO4
2h
450-550°C
Leaching H2O
18-22%
NaCl/Na2CO3
Crystallization
Leaching H2SO4
Leaching Na2CO3
120-200 g/L
0.5-2.5 M
Stabilization
Slag characterization
by Atomic Absorption Spectrophotometer
Elements
Concentration (%)
Vanadium
28.72
Nickel
8.16
Sodium
1.62
Iron
1.60
Fixed carbon
46.57
Volatile matter
2.50
Moisture
1.01
Components distribution of the slag section
by scanning electron microscope (MEB-EDX)
Increase 200x
V
Increase 1500x
Ni
Si
Fe
O
Mineralogical content of the slag
by X-ray diffraction (XRD) in a D8 advance equipment
Slag roasted at 550 and 650 °C
Mineral
Formula
Calcium vanadium oxide
Ca0,17V2O5
Sodium vanadium oxide
Na0,33V2O5 / NaV6O15
Bannermanite
Na0,76V6O15
Cristobalite
SiO2
Grupo plagioclasa
(albita, andesita, anortita)
Nickel vanadium oxide
(Na,Ca)Al(Si,Al)Si2O8
NiV2O6
Recovery of vanadium, nickel and iron
in solution by mean slag leaching
100
90
80
70
60
50
40
30
20
10
0
V
Ni
Fe
Metal recovery in solution (%)
Vanadium, nickel and iron recovery in solution
by agitated leaching (750 rpm) with H2SO4 200 g/L, 25% solids at 70°C.
100
90
80
70
60
50
40
30
20
10
0
0
4
V
8
12
16
Leaching time (h)
Ni
20
Fe
24
Metal recovery in solution (%)
Vanadium, nickel and iron recovery in solution
from agitated leaching (750 rpm) of the solid residue (from H2SO4 leaching)
with Na2CO3 2 M at 75°C.
100
90
80
70
60
50
40
30
20
10
0
0
4
8
12
16
20
Leaching time (h)
V
Ni
Fe
24
Crystallization of the strong solutions
Process
Leaching 1
200 g/L H2SO4
70 °C
25 % solid
Leaching 2
2 M Na2CO3
75 °C
25 % solid
Approximate composition (%)
Vanadium oxy sulphate
V2O3(SO4)2
51
Nickel hidrate sulphate
NiSO4.6H2O
27
Fe2(SO4)3
7
K2 NiSO4.6H2O
5
Na3H(CO3)2. H2O
Na2CO3. H2O
NaV6O16
Ca3(V2O7)(OH)2(H2O)
28
24
16
15
14
Mikasaite
Nickel and potasium hidrate sulphate
Trona
Thermonatrita
Barnesita
Volborthita
Calcium magnesium vanadium oxide
CaMgV2O7
Stabilization of slag cake
The cake produced from leaching sequence with
H2SO4 and Na2CO3 was constituted by
Formula
Approximate
composition (%)
Vanadium nickel oxide
Ni3(VO4)2
56
Calcium aluminum oxide
CaAl2O4
15
Aluminum phospate
AlPO4
8
Iron sulphur
Fe7S8
6
Mineral
50%
Cake
40%
Cement
10%
Lime
 The standard of public
sewer system discharge
(Ecuador)
 U.S. EPA 40 CFR 261.24
standards, EPA 2003
Conclusions
Fly ash
The fly ash has 5.42wt-% iron, 5.31wt-% vanadium and 1.61wt-%
nickel, and amorphous material. (NaV6O15, NiV2O6, Na0.33V2O5,
NiV2O6, Ca0,17V2O5, NaV6O15)
Fly ash was roasted at 350°C for 1.5 hours and agitated leaching
with H2SO4 200 g/L at 25°C, 25wt-% solids for 8 hours at 750 rpm
in order to recover 91wt-% vanadium, 73wt-% nickel and 70wt-%
iron in solution
Conclusions
Slag
The slag has 28.72wt-% vanadium, 8.16wt-% nickel, 1.62wt-%
iron. (Ca0,17V2O5, Na0,33V2O5, Na0,76V6O15, NaV6O15, NiV2O6, SiO2)
Slag was leached with H2SO4 200 g/L at 70°C, 25wt-% solids for 4
hours stirring (750 rpm) followed by another leaching with Na2CO3
2 M, 75°C, 25wt-% solids and 8 hours
in order to recover 75wt-% vanadium, 21wt-% nickel and 34wt-%
iron
The fly ash and slag processing is costly and complex. Their
valorization for vanadium and nickel recovery is possible, but must
be evaluated with large scale essays