iron alum
1.In the process of evaporation-neutralization-crystallization, it was found that most of the impurities (iron, aluminum) in the concentrated leach liquor could be separated from beryllium, when the solution was adjusted to pH1.5 with ammonia gas and cooled to room temperature for crystallization, because of aluminum and iron forming ammonium alum and ferrous ammonium sulphate with the (NH4)2SO4 in the solution.
