Figure 1.
Distribution of the main minerals in the studied sample: (a) magnetite (Mt) and hematite (Hem) structure; (b) minerals permeating the hematite structure; (c) small amounts of pyrite (Py), sphalerite (Sp), pyrrhotite, spinel, chalcopyrite (Ccp) and natural iron; (d) a small amount of pyrrhotite (Po), with an irregular granular shape.
Figure 2.
Microscopic photos of lead and zinc mineral impurities in raw ore samples: (a) irregular granular galena (Gn) with interstitial structure; (b) turbid chalcopyrite (Ccp) distributed in irregular granular sphalerite (Sp).
Figure 3.
Microscopic images of a roasted sample at 750 °C: (a) distribution of hematite (Hem), limonite (Lm), and galena (Gn); (b) irregular distribution of sphalerite (Sp) and pyrite (Py).
Figure 4.
Microscopic images of a roasted sample at 900 °C: (a) Hematite (Hem), Limonite (Lm), and pyrite (Py) granules; (b) granules of galena (Gn), sphalerite (Sp), and FeO.
Figure 5.
Microscopic images of a roasted sample at 1200 °C: (a) dense appearance of iron granules; (b) small granules of galena (Gn) with iron granules.
Figure 6.
Electron images of EPMA showing the microstructures of area 1: (a) the area corresponding to the element mapping analyses; (b) areas selected for the spot analyses.
Figure 7.
Elemental distribution maps observed by EPMA: area 1 (a).
Figure 8.
Electron images of EPMA showing the microstructures of area 2: (a) the area corresponding to the element mapping analyses; (b) areas selected for the spot analyses.
Figure 9.
Elemental distribution maps observed by EPMA: area 2 (b).
Figure 10.
Electron images of EPMA showing the microstructures of area 3: (a) the area corresponding to the element mapping analyses; (b) areas selected for the spot analyses.
Figure 11.
Elemental distribution maps observed by EPMA: area 3 (c).
Figure 12.
Electron images of EPMA showing the microstructures of area 4: (a) the area corresponding to the element mapping analyses; (b) areas selected for the spot analyses.
Figure 13.
Elemental distribution maps observed by EPMA: area 4 (d).
Figure 14.
Electron images of EPMA showing the microstructures of area 5: (a) the area corresponding to the element mapping analyses; (b) areas selected for the spot analyses.
Figure 15.
Elemental distribution maps observed by EPMA: area 5 (e).
Figure 16.
Electron images of EPMA showing the microstructures of area 6: (a) the area corresponding to the element mapping analyses; (b) areas selected for the spot analyses.
Figure 17.
Elemental distribution maps observed by EPMA: area 6 (f).
Figure 18.
EDS spectra of different micro-zones: (a) Fe micro-zone; (b) Pb micro-zone; (c) Zn micro-zone; (d) roasting temperature 750 °C; (e) roasting temperature 900 °C; (f) roasting temperature 1200 °C.
Figure 19.
Effects of reduction roasting temperature on magnetic separation concentrate indicators.
Table 1.
Chemical analysis result of raw sample/(mass fraction, %).
Chemical Composition | TFe | FeO | Pb | Zn | S | P | CaO | MgO |
Content | 47.04 | 1.25 | 0.39 | 0.30 | 1.19 | 0.099 | 2.62 | 1.89 |
Chemical composition | Mn | Cu | SiO2 | Al2O3 | K2O | Na2O | C | Ig |
Content | 0.66 | 0.110 | 20.33 | 2.85 | 0.843 | 0.783 | 0.31 | 2.81 |
Table 2.
Compositions and contents of main minerals in the raw sample/(mass fraction, %).
Minerals | Content | Minerals | Content |
---|
Hematite | 53.0 | Copper-bearing minerals | 0.3 |
Limonite | 7.5 | Quartz | 18.6 |
Magnetite | 4.6 | Feldspar | 7.5 |
Pyrite, pyrrhotite | 1.1 | Calcite, chlorite, actinolite | 2.5 |
Sphalerite | 0.4 | Sericite, biotite | 2.7 |
Galena | 0.3 | Others | 1.5 |
Table 3.
Compositions and contents of main minerals for roasted samples/(mass fraction, %).
Minerals | 750 °C | at 900 °C | 1200 °C | Minerals | 750 °C | at 900 °C | 1200 °C |
---|
CO2 | 4.776 | −1.686 | −14.265 | CaO | 1.834 | 1.569 | 1.942 |
Na2O | 0.313 | 0.294 | 0.254 | TiO2 | 0.152 | 0.121 | 0.175 |
MgO | 0.655 | 0.445 | 0.516 | MnO | 0.943 | 1.458 | 0.98 |
Al2O3 | 4.578 | 3.478 | 4.232 | Fe2O3 | 59.777 | 70.202 | TFe 44.134 |
SiO2 | 20.914 | 16.889 | 21.377 | CuO | 0.151 | 0.171 | 0.109 |
P2O5 | 0.277 | 0.307 | 0.244 | ZnO | 0.337 | 0.343 | 0.128 |
SO3 | 2.009 | 1.395 | 1.648 | BaO | 2.064 | 1.994 | 2.556 |
K2O | 0.809 | 0.634 | 0.835 | PbO | 0.32 | 0.318 | 0.032 |
Table 4.
Iron mineral phase analysis of raw sample/(mass fraction, %).
Iron Phase | Magnetite | Hematite/Limonite | Siderite | Sulfide Minerals | Ferric Silicate | Total Fe |
---|
Fe content | 1.89 | 42.97 | 0.067 | 0.10 | 2.01 | 47.04 |
Distribution | 4.02 | 91.35 | 0.14 | 0.21 | 4.27 | 100.00 |
Table 5.
Lead phase analysis results in raw sample/(mass fraction, %).
Lead Phase | Lead Sulfide | Lead Oxide | Lead Sulfate (Alum) | Plumbojarosite | Total Pb |
---|
Pb content | 0.028 | 0.19 | 0.0095 | 0.16 | 0.39 |
Distribution | 7.23 | 49.03 | 2.45 | 41.29 | 100.00 |
Table 6.
Zinc phase analysis results in raw sample/(mass fraction, %).
Zinc Phase | Zinc Sulfide | Zinc Oxide | Zinc Sulfate | Zinc–Iron Spine | Total Zn |
---|
Zn content | 0.017 | 0.27 | 0.0023 | 0.0087 | 0.30 |
Distribution | 5.71 | 90.60 | 0.77 | 2.92 | 100.00 |
Table 7.
Electron microprobe analyses of selected spots from area 1 (wt.%).
Points | O | Al | Si | S | Ca | Cr | Mn | Fe | Cu | Zn | Pb |
---|
P4 | 22.28 | 0.00 | 0.00 | 0.00 | 0.10 | 0.00 | 0.00 | 77.62 | 0.00 | 0.00 | 0.00 |
P10 | 11.12 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.47 | 88.41 | 0.00 | 0.00 | 0.00 |
P18 | 10.65 | 0.00 | 0.00 | 0.00 | 0.00 | 0.31 | 0.54 | 88.49 | 0.00 | 0.00 | 0.00 |
Table 8.
Electron microprobe analyses of selected spots from area 2 (wt.%).
Points | O | Al | Si | S | Ca | Cr | Mn | Fe | Cu | Zn | Pb |
---|
P2 | 8.76 | 0.00 | 0.83 | 0.00 | 0.16 | 2.35 | 0.00 | 5.30 | 0.00 | 0.82 | 81.78 |
P17 | 7.33 | 0.00 | 0.00 | 0.00 | 0.31 | 0.56 | 0.00 | 2.13 | 2.45 | 0.75 | 86.48 |
P23 | 7.24 | 0.31 | 0.99 | 5.59 | 0.00 | 2.13 | 0.00 | 1.56 | 5.95 | 0.00 | 76.25 |
Table 9.
Electron microprobe analyses of selected spots from area 3 (wt.%).
Points | O | Al | Si | S | Ca | Cr | Mn | Fe | Cu | Zn | Pb |
---|
P4 | 0.00 | 0.00 | 0.00 | 30.95 | 0.00 | 0.00 | 0.00 | 1.43 | 0.00 | 67.62 | 0.00 |
P13 | 2.02 | 0.00 | 5.65 | 29.53 | 0.00 | 0.00 | 0.00 | 1.15 | 0.00 | 61.65 | 0.00 |
P17 | 0.00 | 0.00 | 0.26 | 32.02 | 0.00 | 0.00 | 0.00 | 0.93 | 0.00 | 66.79 | 0.00 |
Table 10.
Electron microprobe analyses of selected spots from area 4 (wt.%).
Points | O | Si | S | Fe | Cu | Zn | Pb |
---|
P5 | 21.92 | 7.11 | 0.21 | 59.47 | 0.00 | 0.00 | 3.84 |
P9 | 35.42 | 10.08 | 2.21 | 40.69 | 0.00 | 1.89 | 0.00 |
P13 | 14.26 | 8.69 | 0.00 | 70.22 | 0.00 | 1.81 | 1.68 |
Table 11.
Electron microprobe analyses of selected spots from area 5 (wt.%).
Points | O | Si | S | Fe | Cu | Zn | Pb |
---|
P4 | 26.17 | 59.18 | 0.57 | 11.32 | 0.52 | 0.00 | 2.23 |
P10 | 9.63 | 0.47 | 0.00 | 89.90 | 0.00 | 0.00 | 0.00 |
P16 | 22.50 | 47.06 | 0.65 | 27.31 | 0.00 | 0.00 | 2.49 |
Table 12.
Electron microprobe analyses of selected spots from area 6 (wt.%).
Points | O | Si | S | Fe | Cu | Zn | Pb |
---|
P6 | 13.97 | 25.30 | 5.56 | 52.16 | 0.00 | 0.00 | 0.00 |
P10 | 2.32 | 5.22 | 0.00 | 91.79 | 0.00 | 0.00 | 0.00 |
P13 | 11.06 | 0.00 | 0.18 | 88.27 | 0.50 | 0.00 | 0.00 |