Figure 1.
The mineralogy of limonitic nickel laterite (G—Goethite, He—Hematite, Ma—Maghemite, E—Enstatite, Si—Stishovite, C—Chromite spinel, R—Resin). (a) Morphology photograph, (b) Optical photograph, (c) SEM analysis photograph.
Figure 1.
The mineralogy of limonitic nickel laterite (G—Goethite, He—Hematite, Ma—Maghemite, E—Enstatite, Si—Stishovite, C—Chromite spinel, R—Resin). (a) Morphology photograph, (b) Optical photograph, (c) SEM analysis photograph.
Figure 2.
Schematic diagram of the pressurized densification sintering process of limonitic nickel laterite in sinter pot tests (1—control cabinet, 2—pressure device, 3—sinter pot, 4—hearth layer, 5—pressurized weight, 6—sinter bed, 7—bar grate, 8—thermocouple, 9—vacuum chamber, 10—condenser tube, 11—air blower, 12—chimney).
Figure 2.
Schematic diagram of the pressurized densification sintering process of limonitic nickel laterite in sinter pot tests (1—control cabinet, 2—pressure device, 3—sinter pot, 4—hearth layer, 5—pressurized weight, 6—sinter bed, 7—bar grate, 8—thermocouple, 9—vacuum chamber, 10—condenser tube, 11—air blower, 12—chimney).
Figure 3.
Sintering performance of limonitic laterite under various external mechanical pressure.
Figure 3.
Sintering performance of limonitic laterite under various external mechanical pressure.
Figure 4.
Metallurgical performance of the product sinter of different sintering processes (A) Traditional sintering process, (B) Pressurized densification sintering process.
Figure 4.
Metallurgical performance of the product sinter of different sintering processes (A) Traditional sintering process, (B) Pressurized densification sintering process.
Figure 5.
Variations of exhaust-gas temperature (a) and vertical sintering speed (b) with external mechanical pressure.
Figure 5.
Variations of exhaust-gas temperature (a) and vertical sintering speed (b) with external mechanical pressure.
Figure 6.
Porous structure of product sinter of different sintering processes (P—Pore, R—Resin), (a) and (b) are porous macrostructures of the sinter of the traditional and pressurized densification sintering processes, respectively; (c) and (d) are porous microstructures of the product sinter of the traditional and pressurized densification sintering processes, respectively.
Figure 6.
Porous structure of product sinter of different sintering processes (P—Pore, R—Resin), (a) and (b) are porous macrostructures of the sinter of the traditional and pressurized densification sintering processes, respectively; (c) and (d) are porous microstructures of the product sinter of the traditional and pressurized densification sintering processes, respectively.
Figure 7.
Porosity and shrinkage of the product sinter of different sintering processes (A) Traditional sintering process, (B) Pressurized densification sintering process.
Figure 7.
Porosity and shrinkage of the product sinter of different sintering processes (A) Traditional sintering process, (B) Pressurized densification sintering process.
Figure 8.
X-ray diffraction patterns of the product sinter of different sintering processes (A) Traditional sintering process, (B) Pressurized densification sintering process.
Figure 8.
X-ray diffraction patterns of the product sinter of different sintering processes (A) Traditional sintering process, (B) Pressurized densification sintering process.
Figure 9.
Microstructure of product sinter (A) of traditional sintering process (H—(Fe, Mg)·(Fe, Al)2O4, H-1—Fe(Fe, Al)2O4, H-2—(Fe, Mg)Fe2O4, K—CaO·(Fe, Mg) Al2O4·SiO2, K-1—CaO·FeAl2O4·SiO2, K-2—CaO·(Fe, Mg)Fe2O4·SiO2, SFCA—silico-ferrite of calcium and alumina, N—NiFe2O4, C—(Fe, Mg)·(Cr, Fe, Al)2O4, P—Pore, R—Resin). (b–f) are the selected areas in (a).
Figure 9.
Microstructure of product sinter (A) of traditional sintering process (H—(Fe, Mg)·(Fe, Al)2O4, H-1—Fe(Fe, Al)2O4, H-2—(Fe, Mg)Fe2O4, K—CaO·(Fe, Mg) Al2O4·SiO2, K-1—CaO·FeAl2O4·SiO2, K-2—CaO·(Fe, Mg)Fe2O4·SiO2, SFCA—silico-ferrite of calcium and alumina, N—NiFe2O4, C—(Fe, Mg)·(Cr, Fe, Al)2O4, P—Pore, R—Resin). (b–f) are the selected areas in (a).
Figure 10.
Microstructure of the product sinter (B) of the pressurized densification sintering process (H—(Fe, Mg)(Fe, Al)2O4, H-1—Fe(Fe, Al)2O4, H-2—(Fe, Mg)Fe2O4, K—CaO·(Fe, Mg)Al2O4·SiO2, SFCA—silico-ferrite of calcium and alumina, N—NiFe2O4, C—(Fe, Mg)(Cr, Fe, Al)2O4, P—Pore). (b–f) are the selected areas in (a).
Figure 10.
Microstructure of the product sinter (B) of the pressurized densification sintering process (H—(Fe, Mg)(Fe, Al)2O4, H-1—Fe(Fe, Al)2O4, H-2—(Fe, Mg)Fe2O4, K—CaO·(Fe, Mg)Al2O4·SiO2, SFCA—silico-ferrite of calcium and alumina, N—NiFe2O4, C—(Fe, Mg)(Cr, Fe, Al)2O4, P—Pore). (b–f) are the selected areas in (a).
Figure 11.
Schematic diagram of the pressurized densification sintering process in industrial applications.
Figure 11.
Schematic diagram of the pressurized densification sintering process in industrial applications.
Table 1.
Energy dispersive spectrum (EDS) analysis results for areas in
Figure 1.
Table 1.
Energy dispersive spectrum (EDS) analysis results for areas in
Figure 1.
Area No. | Elemental Compositions (Atomic Conc, %) | Mineral Phases |
---|
Fe | Cr | Ni | Mg | Al | Si | Ca | O |
---|
1 | 31.59 | 0.59 | 0.26 | 0.45 | 2.72 | 1.21 | 0.78 | 62.40 | Goethite |
2 | 35.27 | 0.67 | 0.34 | 0.89 | 4.28 | 0.68 | 0.29 | 57.58 | Goethite |
3 | 40.36 | 0.62 | 0.13 | 0.22 | 0.85 | 0.21 | 0.18 | 57.43 | Hematite |
4 | 38.91 | 0.23 | 0.15 | 0.69 | 0.79 | 0.11 | 0.21 | 58.91 | Maghemite |
5 | 20.40 | 16.34 | - | 2.12 | 2.49 | 0.33 | 0.27 | 58.05 | Chromite spinel |
6 | 0.11 | - | - | 0.08 | 0.12 | 32.67 | 0.14 | 66.88 | Stishovite |
7 | 0.98 | - | - | 21.37 | 0.03 | 18.96 | 0.28 | 58.38 | Enstatite |
Table 2.
The detail varying of sinter indices of limonitic laterite with external mechanical pressure.
Table 2.
The detail varying of sinter indices of limonitic laterite with external mechanical pressure.
Pressure (Pa) | Tumble Index (%) | Productivity (t·m−2·h−1) | Solid Fuel Rate (kg/t) |
---|
0.00 | 45.87 | 0.97 | 140.52 |
1561 | 50.40 | 1.09 | 130.24 |
3121 | 50.93 | 1.11 | 128.81 |
4682 | 54.27 | 1.13 | 127.26 |
6242 | 54.67 | 1.15 | 126.12 |
7803 | 53.87 | 1.08 | 128.97 |
Table 3.
Chemical compositions of product sinter of different sintering processes (wt%).
Table 3.
Chemical compositions of product sinter of different sintering processes (wt%).
Sintering Processes | Fetotal | FeO | NiO | Cr2O3 | SiO2 | CaO | Al2O3 | MgO |
---|
Traditional sintering process [18] | 43.95 | 21.15 | 1.08 | 3.36 | 7.69 | 10.79 | 4.89 | 6.65 |
Pressurized densification sintering process | 43.73 | 20.59 | 1.09 | 3.68 | 7.76 | 10.83 | 4.85 | 6.61 |
Table 4.
EDS analysis results for areas in
Figure 9.
Table 4.
EDS analysis results for areas in
Figure 9.
Area No. | Elemental Compositions (Atomic Conc, %) | Mineral Phases |
---|
Fe | Cr | Ni | Mg | Al | Si | Ca | O |
---|
1 | 34.02 | 0.23 | 0.16 | 4.78 | 0.56 | 0.43 | 0.32 | 59.50 | Hercynite |
2 | 35.27 | 0.14 | 0.09 | 3.69 | 5.21 | 0.54 | 0.27 | 54.79 | Hercynite |
3 | 16.78 | 17.25 | - | 3.72 | 6.33 | 0.22 | 0.13 | 55.57 | Chromite spinel |
4 | 12.27 | 0.08 | 0.11 | 4.56 | 0.36 | 11.24 | 12.79 | 58.59 | Eutectic olivine phase |
5 | 13.89 | 0.05 | 0.07 | 0.23 | 6.69 | 12.31 | 14.57 | 52.19 | Eutectic olivine phase |
6 | 34.65 | 0.46 | 0.29 | 0.66 | 6.77 | 0.35 | 0.21 | 56.61 | Hercynite |
7 | 11.39 | 0.06 | 0.08 | 4.35 | 5.27 | 10.98 | 13.36 | 54.51 | Eutectic olivine phase |
8 | 31.74 | 0.05 | 16.59 | 0.35 | 0.52 | 0.12 | 0.09 | 50.54 | Nickel-ferric spinel |
9 | 33.68 | 0.13 | 0.25 | 5.39 | 0.45 | 0.15 | 0.12 | 59.83 | Hercynite |
10 | 30.37 | 0.31 | 0.18 | 0.68 | 4.54 | 4.33 | 7.68 | 51.91 | SFCA |
11 | 26.56 | 0.19 | 0.13 | 0.88 | 6.82 | 5.36 | 8.22 | 51.84 | SFCA |
12 | 31.26 | 0.17 | 0.09 | 0.51 | 3.79 | 5.33 | 7.69 | 51.16 | SFCA |
Table 5.
EDS analysis results for the areas in
Figure 10.
Table 5.
EDS analysis results for the areas in
Figure 10.
Area No. | Elemental Compositions (Atomic Conc, %) | Mineral Phases |
---|
Fe | Cr | Ni | Mg | Al | Si | Ca | O |
---|
1 | 12.42 | 21.53 | 0.11 | 3.98 | 6.78 | 0.14 | 0.33 | 54.71 | Chromite spinel |
2 | 32.95 | 0.72 | 0.44 | 3.78 | 7.07 | 0.13 | 0.33 | 54.58 | Hercynite |
3 | 37.61 | 0.17 | 0.51 | 4.92 | 0.52 | 0.18 | 0.51 | 55.58 | Hercynite |
4 | 10.34 | 0.11 | 0.05 | 2.12 | 6.15 | 13.21 | 15.80 | 52.22 | Eutectic olivine phase |
5 | 34.98 | 0.23 | 0.35 | 0.69 | 6.75 | 0.19 | 0.48 | 56.33 | Hercynite |
6 | 34.39 | 0.52 | 0.10 | 5.30 | 0.24 | 0.19 | 0.33 | 58.93 | Hercynite |
7 | 35.28 | 0.28 | 17.54 | 0.80 | 0.31 | 0.20 | 0.27 | 45.32 | Nickel-ferric spinel |
8 | 37.99 | 0.84 | 0.33 | 4.92 | 2.55 | 0.12 | 0.59 | 52.66 | Hercynite |
9 | 28.53 | 0.72 | 0.12 | 0.81 | 5.61 | 4.52 | 6.99 | 52.70 | SFCA |
10 | 34.32 | 0.45 | 0.14 | 0.68 | 3.69 | 4.07 | 6.45 | 50.20 | SFCA |
11 | 35.21 | 0.63 | 0.11 | 0.85 | 3.36 | 4.29 | 6.77 | 48.78 | SFCA |
Table 6.
Mineral compositions of product sinter of different sintering processes (area-%).
Table 6.
Mineral compositions of product sinter of different sintering processes (area-%).
No. | Solid Phases | Liquid Phases |
---|
Hercynite | Chromite Spinel | Nickel-Ferric Spinel | Eutectic Olivine Phases | SFCA |
---|
H | H-1 | H-2 | K | K-1 | K-2 |
---|
A [18] | 17.14 | 20.81 | 23.24 | 2.55 | 1.05 | 17.23 | 2.13 | 7.07 | 8.78 |
B | 23.28 | 15.78 | 16.36 | 3.09 | 1.18 | 20.69 | - | - | 19.62 |
Table 7.
Comparison of the sinter indices of limonitic laterite sintering in industrial production.
Table 7.
Comparison of the sinter indices of limonitic laterite sintering in industrial production.
Sinter Indices | Tumble Index (%) | Productivity (t·m−2·h−1) | Solid Fuel (kg/t) |
---|
Traditional sintering process [18] | 51.07 | 0.90 | 161.04 |
Pressurized densification sintering process | 58.73 | 1.04 | 144.94 |
Table 8.
Anticipated techno-economic benefits of pressurized densification sintering process.
Table 8.
Anticipated techno-economic benefits of pressurized densification sintering process.
Technical Benefits | Economic Benefits |
---|
Proportions (%) | Variations (Thousand t/a) | Unit Prices (RMB/t) | New Profits (Million RMB/a) |
---|
Productivity Improvement | Solid Fuel Rate Reduction | Production Increase | Anthracite Consumption Reduction | Product Sinter | Anthracite | Sinter Production | Anthracite Consumption | Total |
---|
15 | 10 | 300 | 37.04 | 850 | 750 | 255 | 27.78 | 282.78 |