Hydrothermal Synthesis of Na-LTA, Na-X and HS Zeolites from Tunisian Sand and Aluminum Scraps

Abstract

Na-LTA, Na-X and HS zeolites have been prepared from Tunisian sand and aluminum scraps. The alkaline attack of the sand leads to the metasilicate sol used as a source of silica. The aluminum source was prepared by dissolving aluminum in NaOH solution. The influence of several physicochemical parameters such as temperature, crystallization time and the alkalinity of the reaction mixture on the nature and the purity of the obtained products have been investigated.

Geopolymer Materials Based on Natural Pozzolans from the Moroccan Middle Atlas

“…The major band at 1000 cm 1 corresponds to the Si-O-Al/Si elongation vibration. extreme temperature and pressure resulting from the degradation of the silicate and aluminum [42]. Furthermore, the addition of metakaolin to the CPs makes the effect of these peaks considerable, which is in line with the results of [43,44].…”

“…However, the other crystalline phases, such as diopside, augite, and quartz, observed in the diffractograms of raw materials (Figure 7) are not affected by geopolymerization. The faujasite phase is generally synthesized under the conditions of extreme temperature and pressure resulting from the degradation of the silicate and aluminum [42]. Furthermore, the addition of metakaolin to the CPs makes the effect of these peaks considerable, which is in line with the results of [43,44].…”

Synthesis of high value-added Na–P1 and Na-FAU zeolites using waste glass from fluorescent tubes and aluminum scraps

“…To achieve this goal, researches used natural raw materials and low-cost industrial by-products to prepare zeolites (Chaves Lima et al 2019). Inexpensive materials are mainly clays [6][7][8][9] Liu et al, 2019;Yoldi et al, 2019), volcanic glasses [11], Tunisian sand [12,13] or industrial waste products as coal fly, bagasse fly ash [14,9,15], waste sanitary porcelain [16], waste aluminum cans [17], aluminum scraps [12,18,19] and glass wastes [20][21][22][23][24][25][26][27]. Due to the high silica content and its free composition of toxic and hazardous element, glass wastes are important starting materials for zeolite preparation.…”

“…After 6 days of crystallization, the amorphous phase totally disappears in favor of the crystalline phases. The peak intensities of zeolite Na-P1 increase after the prolonged crystallization period up to 6 days[40]. In table 3, is reported the zeolite quantification as function of time from 6 to 10 days.…”

“…Extended reaction time at high temperature and/or high pressure usually results in dense phases. The new phase occurs in the supersaturated solution throughout the dissolution of the former phase[40].…”