Heat treatment process of ammonia alum to aluminium sulfate and/or ammonium sulfate

摘要

In the present invention, there is disclosed a heat treatment process of ammonia alum to aluminium sulfate and/or ammonium sulfate by a single-stage dehydration and thermal decomposition: the proposed process is characterized in that alum is subjected to dehydration by heating thereof in fluidized bed and passage through several zones with successively increasing temperature from a room temperature up to 350 degC for a period of 10 to 60 minutes. Dehydrated product grain size is then adjusted below 0.4 mm and subsequently subjected to thermal decomposition by heating to a temperature ranging from 550 to 700 degC for a period of 15 to 75 minutes to give crystalline aluminium sulfate. Through absorption of the thermal decomposition gaseous components ammonium sulfate solution is obtained and then by optional crystallization thereof crystalline ammonium sulfate can be obtained.