Study on the mechanism of zeolite Y formation in the process of liquor recycling

Abstract

Abstract Crystallization of zeolite Y formation in the process of mother liquor recycling (MLR) has been studied. The zeolite crystallization mother liquor comprises a little sodium silicate as well as minor zeolite, Upon addition of aluminum sulfate, the silicate existed in the mother liquor reacts to form finely divided silica–alumina hydrogel (MLHG) which can be utilized later in zeolite Y formation. The particle of MLHG is relatively small and Si/Al of the gel's framework is a little great. Since amorphous aluminosilicate gel passes through two stages of gelation, the pseudoequilibrium between solid phase and liquid phase of gel is attained rapidly and the time of zeolite Y formation is much reduced. In addition, experiments have also showed that the quantities and the properties of zeolite Y added affect the process of crystallization heavily. Minor quantities of zeolite in the mother liquor have detrimental effect on the zeolite Y formation. Based on studies of crystallization from recycling mother liquor, a model of two-phase transformation for zeolite Y formation has been proposed.