Microwave-Supported Leaching of Electric Arc Furnace (EAF) Slag by Ammonium Salts
Abstract
:1. Introduction
2. Experimental Procedure
3. Results and Discussion
3.1. Calcium Leaching by NH4Cl with Conventional and Microwave Leaching Processes
3.2. Effect of Different Leaching Parameters on Calcium Leaching Ratio from EAF Slag
3.3. Leaching Behaviors of Impurity Ions from EAF Slag
3.4. Removal of Impurity Ions from the Leachate
4. Conclusions
- (1)
- The calcium leaching ratio at the constant temperature in the microwave field increases about 10% than that under the water bath at the same time. The greater the microwave power, the higher the impact of calcium leaching ratio, which proves that microwave treatment can improve the leaching ratio. Meanwhile, the leaching solutions are boiling within several minutes at constant power in the microwave field.
- (2)
- The rapid calcium leaching step (up to 5 min) is possibly due to the easy reaction of calcium silicate and the slower calcium leaching step (after 5 min) is owing to the difficult reaction of calcium ferroaluminates for the hydrolysis of iron and aluminum.
- (3)
- The leaching behaviors of magnesium and calcium ions affected by different leaching parameters are similar and the concentration of aluminum, iron and phosphorus can be neglected.
- (4)
- Calcium ion is probably not precipitated in the real leaching solution from steel slag by NH4Cl solution as its concentration is less than 0.32 mol/L. However, the concentration of magnesium ion starts to drop sharply when the pH value is higher than 10 and it has precipitated completely at pH value of 11.6.
Acknowledgments
Author Contributions
Conflicts of Interest
References
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Spectrum | Mg | Al | Si | P | Ca | Mn | Fe | Possible Phase | |
---|---|---|---|---|---|---|---|---|---|
Figure 3 | 1 | 33.31 | 65.3 | 1.36 | Ca2SiO4(C/S = 1.96) | ||||
2 | 54 | 1.58 | 3.23 | 41.22 | RO phase | ||||
3 | 32.54 | 66.2 | 1.29 | Ca2SiO4(C/S = 2.03) | |||||
4 | 75.4 | 1.79 | 22.8 | RO phase | |||||
5 | 76.8 | 0.84 | 2.32 | 20.04 | RO phase | ||||
6 | 31.98 | 68 | Ca2SiO4(C/S = 2.13) | ||||||
7 | 62.6 | 2.03 | 35.4 | RO phase | |||||
8 | 59 | 3.64 | 37.34 | RO phase | |||||
9 | 6.55 | 5.59 | 66.9 | 4.34 | 16.66 | - | |||
10 | 32.24 | 66.3 | 1.42 | Ca2SiO4(C/S = 2.07) | |||||
11 | 31.88 | 67.2 | 0.9 | Ca2SiO4(C/S = 2.11) | |||||
12 | 13.37 | 50.5 | 36.18 | CaFA(C/(A + F) = 1.02) | |||||
13 | 59.1 | 5 | 35.94 | RO phase | |||||
Figure 4 | 1 | 1.85 | 1.39 | 63.84 | 4.64 | 23.48 | 1.01 | 3.79 | Calcium silicate after leached |
2 | 51.47 | 2.32 | 3.40 | 42.81 | RO phase | ||||
3 | 68.96 | 0.92 | 3.15 | 26.98 | RO phase | ||||
4 | 33.39 | 0.14 | 1.25 | 5.28 | 59.94 | RO phase | |||
5 | 1.12 | 1.90 | 55.37 | 13.43 | 24.99 | 3.19 | Calcium silicate after leached | ||
6 | 2.91 | 4.23 | 62.41 | 8.42 | 18.33 | 1.17 | 2.53 | Calcium silicate after leached | |
7 | 9.60 | 1.44 | 47.54 | 41.42 | CaFA(C/(A + F) = 0.93) |
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Tong, Z.; Ma, G.; Zhang, X.; Cai, Y. Microwave-Supported Leaching of Electric Arc Furnace (EAF) Slag by Ammonium Salts. Minerals 2017, 7, 119. https://doi.org/10.3390/min7070119
Tong Z, Ma G, Zhang X, Cai Y. Microwave-Supported Leaching of Electric Arc Furnace (EAF) Slag by Ammonium Salts. Minerals. 2017; 7(7):119. https://doi.org/10.3390/min7070119
Chicago/Turabian StyleTong, Zhibo, Guojun Ma, Xiang Zhang, and Yongsheng Cai. 2017. "Microwave-Supported Leaching of Electric Arc Furnace (EAF) Slag by Ammonium Salts" Minerals 7, no. 7: 119. https://doi.org/10.3390/min7070119