中国有色金属学报(英文版)
Transactions of Nonferrous Metals Society of China
| Vol. 24 No. 10 October 2014 |
（1. National Engineering Laboratory for Hydrometallurgical Cleaner Production Technology,
Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China;
2. School of Materials Science and Engineering, University of Science and Technology, Beijing 10083, China）
Abstract:In order to clean production of chromium compounds, it is a critical process to remove aluminates and utilize aluminum compounds from artificial chromate alkali solutions. The effects of Na2CrO4 on the neutralization curve, Al(OH)3 precipitation efficiency and induction period of bayerite were investigated. The results indicate that the neutralization curve of the artificial chromate alkali solutions shows three distinct regions and its induction period is longer than that of pure sodium aluminate solutions at the same aluminum concentration. And the decreased temperature and volume fraction of CO2 enhance the particle size of bayerite β-Al(OH)3. Bayerite composed of agglomerates of rods and cone frustums was obtained from alkali metal chromate solutions with 28.5% CO2 (volume fraction) at temperatures ranging from 50 °C to 70 °C. Coarse bayerite with particle size (d50) from 24.2 μm to 29.3 μm extremely has few impurities, which is suitable for comprehensive utilization.
Key words: chromate alkali solutions; bayerite; carbonization; crystallization; precipitation efficiency
