Introduction
Materials
Constituent | GMT (m/m) | FA (m/m) | BOF slag (m/m) |
---|---|---|---|
Na2O | 0.27 | 0.07 | 0.02 |
MgO | 5.16 | 0.62 | 3.32 |
Al2O3 | 6.98 | 25.34 | 6.63 |
SiO2 | 74.5 | 47.97 | 14.8 |
P2O5 | 0.083 | 0.67 | 0.05 |
SO3 | 3.05 | 1.33 | 1.1 |
Cl | 0.18 | 0.02 | – |
K2O | 1.26 | 1.26 | 0.02 |
CaO | 0.53 | 7.26 | 41.1 |
TiO2 | 0.44 | 2.71 | 0.3 |
V2O5 | 0.03 | 0.00 | – |
Cr2O3 | 0.12 | 0.06 | 0.01 |
MnO | 0.06 | 0.08 | 3.91 |
Fe2O3 | 7.03 | 10.01 | 27.3 |
NiO | 0.05 | 0.02 | 0.02 |
CuO | 0.01 | 0.02 | – |
ZnO | 0.02 | 0.02 | 0.01 |
Rb2O | 0.01 | 0.01 | – |
Y2O3 | 0.01 | 0.14 | 0.23 |
ZrO2 | 0.02 | 0.11 | – |
Nb2O5 | 0.01 | 0.00 | – |
BaO | 0.08 | 0.16 | – |
PbO | 0.02 | 0.13 | 0.18 |
ThO2 | 0.01 | 0.01 | 0.02 |
Methods
Determination of CASH/CSH phase
Determination of geopolymer phase
Statistical analysis
Results and discussion
Effect of BOF slag/FA content and KOH concentration
KOH concentration | 5 M | 10 M | 15 M |
---|---|---|---|
Free Ca2 + (ppm) | 35 | 20 | 100 |
Effect of elevated curing temperature
XRD analysis of geopolymers
Ftir
Sem
Tclp
50 FA precursor material | 50 FA geopolymer | 50 BOF precursor material | 50 BOF geopolymer | Statutory limits (ppm) (South African water Guideline 1996) | |
---|---|---|---|---|---|
Fe | 14.65 | 3.54 | 34.55 | 1.87 | 5 |
Ni | 7.34 | 0.31 | 6.67 | 0.21 | 0.4 |
Cu | 3.44 | 0.98 | 4.44 | 0.88 | 2 |
Mn | 2.67 | 1.41 | 5.87 | 1.12 | 10 |
Zn | 1.45 | 0.87 | 1.33 | 0.34 | 4 |
Sulphates | 10,325 | 3100 | 10,489 | 2245 | 6000 |
pH | 6.45 | 11.22 | 8.34 | 11.78 | – |
Sample | Fe (mg m−2) | Zn (mg m−2) | Mn (mg m−2) | Ni (mg m−2) | Cu (mg m−2) |
---|---|---|---|---|---|
50 FA | 100 | 82 | 110 | 25 | 10 |
50 BOF | 110 | 89 | 85 | 12 | 20 |