کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
213419 | 462099 | 2007 | 10 صفحه PDF | دانلود رایگان |

New methods were explored to intensify the precipitation of gibbsite from seeded caustic sodium aluminate liquor: gibbsite crystal seed was activated by boiling in distilled water and 15-crown-5-ether was used as additive in this investigation. Both methods promoted precipitation under selected conditions. The stability of pure sodium aluminate solution decreases in the presence of a high concentration of 15-crown-5-ether, this effect was examined using 27Al NMR. Particle size analyses showed that the product became finer when either intensifying method was introduced. The intensifying mechanism was proposed as follows: desorption of organic contaminants and adsorption of additive molecules primarily take place on the surface of large seed particles where active sites are denser, thus precipitation is promoted; available supersaturation for the small seed particle decreases as the large seeds grow rapidly thereby decreasing agglomeration giving a finer product. Scanning Electronic Microscope (SEM) images of samples support this mechanism.
Journal: Hydrometallurgy - Volume 89, Issues 1–2, September 2007, Pages 107–116