Synthesis, optimisation and characterisation of the zeolite NaA using kaolin waste from the Amazon Region. Production of Zeolites KA, MgA and CaA

Abstract This study aimed to use industrial kaolin waste from the Capim (KC) and Jari (KJ) regions of northern Brazil in the synthesis of the zeolite NaA. A temperature of 110 °C was kept constant throughout the synthesis process of the zeolite NaA, and the durations and Na/Al ratios were altered. The results of X-ray diffraction (XRD) analysis showed that high purity zeolite NaA with a high degree of structural order was produced in the following conditions: a Na/Al ratio of 1.64 for KC and KJ and synthesis durations of 18 h for KC and 20 h for KJ. According to the XRD results, which indicated the formation of the zeolites KA, MgA and CaA, the process of cation exchange between the Na from zeolite NaA and the K, Mg and Ca from the solutions was efficient.