Bubble Generation, Design Modeling and Optimization of Novel Flotation Columns for Phosphate Beneficiation. Volume 2
To select frothers for sparger performance and phosphate flotation, 28 commercially available frothers were investigated by measuring air holdup under various operational conditions in an air/water system. The detailed description of operation characteristics for different commercially available spargers is given in this report. Generally speaking, an eductor sparger and two-phase ejector have strong air dispersion ability, simple operation, less clogging potential, and less energy consumption, compared with other external spargers. However, the addition of much more water to the eductor is required to aspirate atmospheric air into the sparger and to disperse into fine bubbles. For phosphate rougher flotation, the water added by the eductor meets the requirement for dilution of the dewatered reagentized feed. In applications where the feed is not dewatered, the eductor water may cause excess water addition to the flotation system. This problem can be overcome by properly selecting the eductor size to minimize the addition water amount. An economic performance measure was developed, which includes recovery, grade, and the reagent prices. A parametric study was conducted on both unsized and sized feeds to optimize column flotation. Another useful product of this project is a novel “intelligent” model for phosphate column flotation which combines a first-principles model with artificial neural networks. The model learns from column operational data: the more data presented to the model, the more accurate it becomes.