School of Chemical Technology, KIIT Deemed to Be University, Bhubaneswar, 751024, Odisha, India.
H& EM Division, CSIR-Institute of Mineral and Materials Technology(IMMT), Bhubaneswar, 751013, Odisha, India.
Environ Sci Pollut Res Int. 2023 Aug;30(39):90195-90208. doi: 10.1007/s11356-023-26182-3. Epub 2023 Mar 11.
The application of organic acids towards the extraction of both Cu and Cr from the Cu-Cr spent catalyst was investigated. A series of organic acid such as acetic acid, citric acid, formic acid, ascorbic acid and tartaric acid were adopted, and after screening, acetic acid showed a profound effect on dissolution of either of the metals over other green reagents. The spent catalyst was characterized by XRD and SEM-EDAX to confirm the existence of the oxide phase due to both Cu and Cr metals. For efficient dissolution of metals, the critical parameters such as agitation speed, acetic acid concentration, temperature, particle size, as well as S/L ratio affecting on it was systematically investigated. It was observed that at approximately 99.99% of Cu along with 62% of Cr was extracted at the optimised conditions (agitation speed: 800 rpm, 1.0 M CHCOOH, 353 K temperature, particle size of (75-105) µm and S/L: 2% (W/V). The leach residue obtained after the first stage of leaching was analysed by SEM-EDAX and XRD, indicating no peaks due to the presence of Cu ensures complete dissolution of Cu at the optimum conditions. Further, to attain the quantitative leaching yield of Cr, the leach residue obtained after the first stage was sequentially investigated using varied acetic acid concentration and temperature. Leaching kinetics was established based on obtained results at the varied operating parameters, and it revealed support for fitting a model of the leaching data to the shrinking core chemical control model (R = 0.99) for both metals (Cu and Cr). The activation energy determined to be 34.05 kJ mol and 43.31 kJ mol for Cu and Cr, respectively, validates the proposed leaching kinetics mechanism.
研究了有机酸在从废 Cu-Cr 催化剂中提取 Cu 和 Cr 中的应用。采用了一系列有机酸，如乙酸、柠檬酸、甲酸、抗坏血酸和酒石酸，并经过筛选，发现乙酸对溶解这两种金属的效果比其他绿色试剂都要好。采用 XRD 和 SEM-EDAX 对废催化剂进行了表征，以确认由于 Cu 和 Cr 金属的存在而存在氧化物相。为了有效地溶解金属，系统地研究了影响溶解的关键参数，如搅拌速度、乙酸浓度、温度、粒度以及固液比。结果表明，在最佳条件下（搅拌速度为 800 rpm、1.0 M CHCOOH、353 K 温度、（75-105）µm 粒度和 S/L 比为 2%（W/V）），Cu 的提取率约为 99.99%，Cr 的提取率为 62%。第一阶段浸出后得到的浸出残渣用 SEM-EDAX 和 XRD 进行了分析，表明不存在由于 Cu 的存在而导致的峰，这确保了在最佳条件下 Cu 完全溶解。此外，为了获得 Cr 的定量浸出率，在第一阶段浸出后，对浸出残渣进行了使用不同乙酸浓度和温度的连续浸出。根据在不同操作参数下获得的结果，建立了浸出动力学，结果表明，该模型适用于拟合浸出数据到收缩核化学控制模型（R=0.99），适用于两种金属（Cu 和 Cr）。确定 Cu 和 Cr 的活化能分别为 34.05 kJ/mol 和 43.31 kJ/mol，验证了所提出的浸出动力学机制。
