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Effect of alkali roasting and sulfatization on the extraction of different metal oxides from waste alum sludge
Water treatment plants (WTP) generate a significant amount of sludge as byproducts with environmentally harmful elements. Thus, this work focused on the recycling of alum sludge through the extraction of different metal oxides, i.e., Al2O3, Fe2O3 and SiO2, for use in different applications, such as...
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Published in: | Ceramics international 2021-08, Vol.47 (16), p.23181-23193 |
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Main Authors: | , , , , |
Format: | Article |
Language: | English |
Subjects: | |
Citations: | Items that this one cites Items that cite this one |
Online Access: | Get full text |
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Summary: | Water treatment plants (WTP) generate a significant amount of sludge as byproducts with environmentally harmful elements. Thus, this work focused on the recycling of alum sludge through the extraction of different metal oxides, i.e., Al2O3, Fe2O3 and SiO2, for use in different applications, such as ceramics, cement, and agriculture. The extraction of Al2O3, Fe2O3, and SiO2 from alum sludge was performed using sulfatization and roasting to compare which of the two processes could produce the metal oxides of the highest purity. Precipitated powders were calcined at 700°, 900° and 1100 °C. Moreover, the obtained prepared and calcined powders were characterized by studying their phase compositions, microstructure, particle size, and surface area. Results indicated that roasting achieved the highest yield of alumina. Iron oxide was extracted mostly in maghemite form through roasting after calcination at 1100 °C. Further, silica was obtained in cristobalite and quartz phases after calcination at 1100 °C for the samples prepared through sulfatization. However, these phases of silica were combined with albite and obtained after calcination at 1100 °C for the samples prepared through roasting method. |
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ISSN: | 0272-8842 1873-3956 |
DOI: | 10.1016/j.ceramint.2021.05.030 |