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- Title
Recovery of tungsten from spent selective catalytic reduction catalyst by sulfuric acid precipitation and evaporation crystallization method.
- Authors
Wang, Bo; Yang, Qiaowen; Chen, Yue; Bai, Ruoyan; Cao, Hui
- Abstract
BACKGROUND: Selective catalytic reduction (SCR) can effectively handle NOx from flue gas in coal‐fired power plants. However, as the core part of the SCR method, V2O5–WO3/TiO2 catalyst has a limited operational life in the complex flue gas environment. The recovery of rare metals from spent catalyst would not only bring economic benefits but also solve environmental problems. The process of reducing acid leaching and further roasting‐water leaching could realize the efficient recycling of vanadium, tungsten and titanium. RESULTS: After reducing acid leaching and roasting‐water leaching to treat spent SCR catalyst, the obtained solution containing tungsten was used as the raw material in this study. The optimal pH value of solution for removal of silicon and aluminum impurities was 9.2–9.5. The best tungsten precipitation conditions were shown as follows: a tungsten concentration of 30 g L−1, a sulfuric acid concentration of 8 mol L−1, reaction temperature of 70 °C and reaction time of 2 h. Under the optimal tungsten precipitation conditions, the tungsten precipitation efficiency can reach 92.53%. Finally, in order to further improve the purity of the crude H2WO4, the crude H2WO4 was fully dissolved in ammonia, followed by filtration and evaporation crystallization to obtain 5(NH4)2O.12WO3.5H2O (APT) crystals with a purity of 93.05 wt%. The crystallization efficiency of APT was 73.37% at 60 °C for 2 h with a rotor speed of 400 rpm. CONCLUSION: These results indicated that a higher purity of APT crystals can be obtained by the steps of removing silicon and aluminum, precipitation of tungsten by sulfuric acid, ammonia dissolution and evaporation crystallization. © 2023 Society of Chemical Industry (SCI).
- Subjects
SOCIETY of Chemical Industry (Great Britain); SALTING out (Chemistry); CATALYTIC reduction; SULFURIC acid; TUNGSTEN; ACID catalysts; FILTERS &; filtration; LEACHING
- Publication
Journal of Chemical Technology & Biotechnology, 2024, Vol 99, Issue 4, p797
- ISSN
0268-2575
- Publication type
Article
- DOI
10.1002/jctb.7558