Cheng Wenting, Li Jie, Deng Jianhang, Li Yang, Cheng Fangqin
Institute of Resources and Environmental Engineering, Shanxi University, Taiyuan 030006, China.
Shanghai Shangde Experimental School Noble Academy, Shanghai 201315, China.
ACS Omega. 2024 Feb 16;9(8):9286-9294. doi: 10.1021/acsomega.3c08452. eCollection 2024 Feb 27.
Huge amounts of spent denitration catalysts are produced annually as waste from the flue gas denitration process, which will cause resource waste and environmental pollution. It is important to develop an efficient method for the recovery of metals from spent denitration catalysts. In this work, the leaching of vanadium (V) from the spent denitration catalyst by the sulfuric acid/oxalic acid combined solvent was investigated. Factors that influence the leaching rate of V have been studied. Results showed that the optimal leaching rate was 95.65% by 20 wt % sulfuric acid and 0.3 mol·L oxalic acid with a liquid-to-solid ratio of 20 mL·g at 140 °C for 7 h. For further study of the leaching process, the leaching mechanism of V was explored subsequently. Results indicated that sulfuric acid provided a strongly acidic environment, which was beneficial to transformation, complexation, and redox reactions of V in the mixed acid leaching system. Meanwhile, oxalic acid with excellent complexation and reducing-dissolving properties promoted the formation of stable water-soluble VO. The "complex effect" generated from the combined acids was greatly favored for leaching V from the spent denitration catalyst.
烟气脱硝过程每年会产生大量废弃脱硝催化剂，这将导致资源浪费和环境污染。开发一种从废弃脱硝催化剂中回收金属的有效方法至关重要。在本工作中，研究了用硫酸/草酸混合溶剂从废弃脱硝催化剂中浸出钒（V）。研究了影响V浸出率的因素。结果表明，在140℃下，以20 mL·g的液固比，用20 wt%硫酸和0.3 mol·L草酸浸出7 h时，最佳浸出率为95.65%。为进一步研究浸出过程，随后探讨了V的浸出机理。结果表明，硫酸提供了强酸性环境，有利于V在混合酸浸出体系中的转化、络合和氧化还原反应。同时，具有优异络合和还原溶解性能的草酸促进了稳定水溶性VO的形成。混合酸产生的“络合效应”极大地有利于从废弃脱硝催化剂中浸出V。
