| 摘要 |
<p>The nucleation hydrate is prepared by complete carbonatation of alkalimetal-aluminate (specif. Na), maintaining the temperature below a maximum proportional to the free alkali conc. in the soln. (pref. 29-43 degrees C), after which an alkalialuminate solution (temp. pref. not above 38 degrees C) is stirred in to start the crystallizing process which is completed with constant stirring. The aluminate soln. pref. contains a little organic matter free iron solution as 'sinter' liquid it is pref. a 'Bayer liquid'. Spec. bayerite of surface area 30-100m2/g paricles size 0.4-30 mu is produced at 26-82 degrees C (esp. 65-77 degrees C). The precipitated hydrate is sepd. at 38-54 degrees C. The product is used for filling or coating paper.</p> |
