| 摘要 |
<p>The invented heat treatment process of ammonia alum to aluminium sulfate and ammonium sulfate by two-stage dehydration and thermal decomposition is carried out in such a manner that in the first stage ammonia alum is brought into contact with combustion products at a temperature ranging from 500 to 900 degC and subsequently it is heated in a fluidized bed for a period of 20 to 60 minutes to a temperature in the range of 140 to 350 degC. Grain size of the obtained intermediate is then adjusted to 0.15 to 0.5 mm and in the second stage said intermediate is dehydrated by contacting thereof with combustion products at a temperature ranging from 300 to 800 degC, whereupon it is subjected to thermal decomposition at a temperature ranging from 550 to 700 degC for a period of 15 to 75 minutes to give crystalline aluminium sulfate. A solution of ammonium sulfate or crystalline ammonium sulfate is obtained by absorption from gaseous components and optional subsequent crystallization.</p> |
