Synthesis of Zeolite from Electrolytic Manganese Residue: Investigation on the Variation of the Propert of Zeolite during the Conversion Process

Abstract

In this study, the cation exchange capacity (CEC); phosphate immobilization capacity (PIC); and chemical, mineralogical, and morphological characteristics of the synthesized electrolytic manganese residue (EMR) based zeolite (EMRZ) were systematically investigated during the synthesis process. By varying synthesis conditions, different zeolites with different purity were generated, and it was proven that a lower Si/Al ratio, relatively higher temperature, and relatively longer time favored the synthesis of zeolite. Besides, the decrease in Si/Al ratio and variation within a narrow range contributed to the forming of Al rich zeolite. Meanwhile, the discrepancy of CEC and PIC of EMRZ contributed to the case in which various elements in EMRZ do have an impact on CEC (Na2O element and type of zeolite) and PIC (calcium and iron components). Moreover, the synthesis conditions were optimized and evaluated in terms of their CEC, specific surface area (SSA), and crystallinity. According to the analyses using XRD, FE-SEM, and XRF and the SSA analysis, the EMRZ (mainly zeolite A, LTA) synthesized under the optimum conditions (initial Si/Al ratio of 1.5, at 100°C, for 1.5 h) was found to be mainly composed of highly ordered cubic zeolites A crystals with a Si/Al ratio of 1.02 and a CEC of 3.45 meq/g.