| 摘要 |
In the prodn. of coarse alumina by hydrolysis of a pregnant liquid (I), consisting of conc. Na alumina soln. in the presence of an Al hydroxide seed material (II) and calcination of the Al hydroxide pptd. (I) is distributed to an agglomeration-washing series (A) and a cementation-washing series (B). In (A), fine (II) is added to (I) agglomerated and washed, giving coarse particles. Coarse (II) is used in later stages of (A) and in (B) and the coarse material obtd. is washed and calcined. Alumina is used mainly as raw material in Al mfr. by electrolysis. The coarse prod. forms only a small amt. of dust. The process is simple and relatively high productivity can be maintained. |
