ABSTRACT
Alums are very important products because of their vast array of uses. In this investigation, about 91% kaolinite fraction was recovered from Kankara kaolin after beneficiation. The silica-alumina ratio of 2:1 obtained after calcination conformed to typical literature values. The raw clay yielded 72.91% alum (in terms of % wt of alumina extracted from the clay) while the fully beneficiated clay yielded 81.30% alum. Similarly, about 86% reduction in MgO content was achieved via beneficiation of the raw clay. When different salting agents (i.e sodium, potassium and ammonium sulfates and ethanol) were added to the dealumination filtrate, alum yields (in terms of % wt of alumina extracted from the clay) ranges between 60 to 81.30 % in contrast to the unsalted filtrate which gave a corresponding value of 37.63%. It was also observed that as the concentration of the potassium sulfate solution increased, alum yield also increased and the quality of the potassium alums was significantly constant. When dried at 2500C for 6 hours, the soda, potassium and ammonium alums showed a loss in weight of about 47.00% corresponding to the occluded acid and crystallization water content. The use of the heat of hydration of sulfuric acid in water for the dealumination process gave 81.30% alum yield, while the use of additional heat from oil bath for up to 3 hours gave a marginal increment of only about 6% yield. It was on this basis that dealumination without external heating source is recommended.