Chemical soaking of kaolin
Kaolin powder is soaked in saturated urea solution by chemical reagent soaking method. At the same time, the kaolin powder is heated to 30-80 C, and a small amount of dispersant is added to make the kaolin disperse sufficiently. Then the kaolin is stirred at high speed, so that the crystals are laminated and peeled off. Benzidine and acetamide can also be used instead of urea. The neutral aqueous solution of AlCl3 was mixed with Na2SiO3 in the ratio of 1:0.75 to 1:5 to produce precipitation. At 110 degrees Celsius, Al2O3? 2SiO2? 2H2O was obtained by drying.