Application of Response Surface Methodology (RSM) in Production of Potassium Aluminium Sulphate from Egyptian Kaolin

Alum is a commonly a hydrated double sulfate salt of aluminum with the general formula XAl(SO4)(2)<middle dot>12H(2)O, wherein X is a monovalent cation that includes Ammonium or Potassium. It is used in water purification, medicines, cosmetics, food preparation, and flame-retardant paper and textiles. The goal of the present work is to produce potassium aluminum sulfate (PAS) from local kaolin. Alum is produced through leaching of metakaolin with H2SO4 to obtain liquid aluminum sulphate (AS), which crystallized with potassium sulphate to produce crystalline PAS. Response surface methodology (RSM) (Box-Behnken) technique is used to optimize the leaching conditions to maximize the yield. The studied parameters are temperature (70 -210 degrees C), acid concentration (2- 6 Molar), and Time (60 -120 min). A predicted maximum yield of 97.3062 % was obtained on using 5.3 M acid concentration, 180 degrees C temperature of reaction and of 92 min for time. The suggested model (quadratic) was found to be highly significant, withR(2) (0.9764) and P value < 0.005. The determined maximum yield is tested experimentally through five runs at optimum conditions. The average yield of the five runs is 94.592 % with a standard deviation 0.89, the percentage error did not exceed 2.49 %. Which confirms the validity of the model.