The reaction products resulting from the interaction between kaolin ore and ammonium sulphate depend on molar ratios between reactants, reaction temperature and time of interaction. The reaction products were characterized by means of XRD. They were composed of silica, unreacted kaolin ore, traces of iron, magnesium, calcium, titanium and NH,Al(SO,), and (NH,),Al(SO,),. The last compound was produced alone at 553 K, whereas mixtures of them were produced between 553 and 823 K after a short time of interaction (0.5 h). On other hand the former compound was produced alone after longer heating (c. 2 h). At 823 K, a mixture composed of Al,(SO,) and NH,AI(SO,), was identified after 0.5 h, whereas anhydrous aluminium sulphate was detected alone after heating the reaction mixture for 2 h. The transformation of (NH,),AI(SO,), into NH,Al(SO,), and alumina leads to a decrease in the percentages of extracted alumina from kaolin ore at relatively higher temperatures and/or longer heating of reaction mixtures. The investigation was also devoted to establishing the possible reactions which lead to the formation of Fe,O,, MgO, CaO and TiO, as soluble salts together with aluminium compounds. The percentages of their extraction are low compared with the original quantities found in kaolin ore. From the obtained results, both Al,(SO,), and NH,Al(SO,), can be prepared from local kaolin with a reasonable degree of purity which makes it possible to produce them for use for different industrial and pharmaceutical purposes.