Abstract
The precipitation of gelatinous aluminium hydroxide from aqueous solutions of aluminium sulphate and ammonium, potassium and sodium slums with sodium hydroxide solution was investigated under different conditions. The resulting precipitates were examined by X-ray diffraction study, infrared spectroscopy and thermal analysis (TG and DTA). It was determined that the composition of the precipitates depends on experimental conditions, in particular the pH value of aqueous solutions: this composition varied in the order of amorphous aluminium hydroxide, pseudoboehmite and bayerite as the pH of aqueous solutions in their formation increased, although the precipitation behavior was influenced by aluminium salts containing sulphate. The results obtained are discussed in comparison with the precipitates from aqueous solutions of chloride or nitrate of aluminium with alkali.
