Spherical agglomeration of nickel-manganese-cobalt hydroxide in turbulent Batchelor vortex flow
| Autor: | Xiaotong Sun, Woo-Sik Kim, Jinsoo Kim |
|---|---|
| Rok vydání: | 2021 |
| Předmět: |
Materials science
Cobalt hydroxide Turbulence General Chemical Engineering Batchelor vortex Analytical chemistry chemistry.chemical_element 02 engineering and technology General Chemistry 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences Industrial and Manufacturing Engineering 0104 chemical sciences Reaction rate chemistry.chemical_compound Nickel chemistry Agglomerate Shear stress Environmental Chemistry Hydroxide 0210 nano-technology |
| Zdroj: | Chemical Engineering Journal. 421:129924 |
| ISSN: | 1385-8947 |
| DOI: | 10.1016/j.cej.2021.129924 |
| Popis: | In this study, turbulent Batchelor vortex flow, due to its periodic fluid motion, was used to produce highly dense and spherical Ni-Mn-Co (NMC) hydroxide agglomerates (microparticles) in a rotation disk crystallizer. A high shear stress (1500 rpm) in the turbulent Batchelor vortex regime, and the presence of ammonia at a pH of 12, help form spherical shaped agglomerates with a high tap density (2.1 g/m3) from irregular shaped agglomerates. The coefficient of variation (0.38) of the agglomerates also narrowed while using this approach. When sufficient ammonia was supplied to form a complex ([M(NH3)n]2+) with all M2+, the reaction rate with OH– slowed and the agglomeration process was affected by the high shear stress in a sufficient amount of time. On the contrary, when ammonia is not present in the reaction solution, free M2+ ions rapidly react with OH– ion, resulting in irregular shaped agglomerates. The pH was related to the OH– concentration and all of the [M(NH3)n]2+ complex was consumed during the agglomeration process when the OH– concentration reached a mol ratio of 1:2 ([M(NH3)n]2+:OH–). When the ammonia feeding rate was higher than 1.2 mL/min, highly dense agglomerate was obtained. However, the [M(NH3)n]2+ complex could not be generated when the pH exceeded a value of 12, according to the mass and equilibrium calculations. In addition, the residence time was significantly shorter (30 min) in the turbulent Batchelor vortex flow regime compared to previous studies (~12 to 50 h). This study suggests that the high shear stress in the turbulent Batchelor vortex flow regime can be effectively used for making highly dense and spherical NMC hydroxide, with high tap density, in a short amount of time. |
| Databáze: | OpenAIRE |
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