| 摘要 |
In the production of alumina from aluminum hydroxide, a) aluminum hydroxide is purified with washing water in a hydrate filter, b) the purified aluminum hydroxide is at least partly dried and/or precalcined in at least one preheating stage, c) this pretreated aluminum hydroxide is calcined in a fluidized-bed reactor to obtain alumina, d) the alumina obtained is cooled in at least one indirect cooling stage using water as coolant, e) the steam (D) obtained from the cooling water due to the heat transfer in the indirect cooling stage is separated from the liquid fraction (A) of the exit stream from the cooling stage (E), f) and at least one partial stream (T) of the liquid fraction (A) is guided to the hydrate filter and used there as washing water for purifying the aluminum hydroxide in the hydrate filter. In accordance with the invention, an additional water stream (Z) is added to the partial stream (T) of the liquid fraction (A) guided to the hydrate filter and the mixing ratio of the two streams (T, Z) is adjusted such that the washing water stream (W) resulting therefrom has a constant maximum temperature value below the boiling point of water and the volume flow required by the hydrate filter as washing water. |
