Synthesis of zeolites from mechanically activated kaolin clays

The Effect of Thermal and Mechanical Treatments on Kaolinite: Characterization by XPS and IEP Measurements

“…The NMR data showed the presence of tetra-, penta-, and octahedral Al coordinated forms in the mechanically treated samples and only tetra-and octahedral in the 500 and 900°C kaolinite transformation, respectively. Additionally, it was shown that kaolinite modified by grinding is reactive for zeolite synthesis, producing products similar to those obtained when kaolinite undergoes thermal activation (6). The well-crystallized kaolin can not supply the necessary concentration of aluminate and silicate ions for the crystallization of NaA zeolite, whereas in the mechanically and thermally treated samples this component can be extracted from the collapsed structure.…”

Formation of Inorganic Supports and Components of Catalysts with the Help of Mechanical Activation

“…Äëÿ ïîëó÷åíèÿ öåîëèòîâ òèïà À è Õ àâòîðû [121,122] ïîäâåðãàþò ñìåñü èñõîäíûõ êîìïîíåíòîâ (êàîëèíèò, NaOH è âîäà) ÌÀ â ïëàíåòàðíîé ìåëüíèöå â òå÷åíèå 23 ÷. Ìåõàíè-÷åñêàÿ àêòèâàöèÿ êàîëèíà ðàññìàòðèâàåòñÿ â ýòîì ñëó÷àå êàê àëüòåðíàòèâà ñòàäèè ïðîêàëèâàíèÿ ïðè òðàäèöèîííîì ñèíòåçå öåîëèòà À [123]. Ñðàâíèòåëüíûé àíàëèç [124] ñâîéñòâ öåîëèòà À, ñèíòåçèðîâàííîãî èç ìåõàíîàêòèâèðîâàííîãî èëè òåðìîîáðàáîòàííîãî êàîëèíà, ïîêàçûâàåò, ÷òî ÌÀ êàîëèíà ñïîñîáñòâóåò ñèëüíîé ðàçóïîðÿäî÷åííîñòè ñòðóêòóðû êàîëèíà è áîëüøåé ëàáèëüíîñòè èîíîâ àëþìèíèÿ, êóáè÷åñêàÿ ìîðôîëîãèÿ ñèíòåçèðîâàííîãî öåîëèòà A â ýòîì ñëó÷àå ìåíåå ñîâåðøåííà, êàòèîíîîáìåííàÿ ñïîñîáíîñòü ïðè ùå-ëî÷íîé àêòèâàöèè ìåõàíîàêòèâèðîâàííîãî êàîëèíà ïîâûøàåòñÿ íå ñòîëü ñóùåñòâåííî.…”

Um novo procedimento de síntese da zeólita A empregando argilas naturais

“…A fase metacaulim é uma fase amorfa do caulim e é considerada mais reativa. 8,9 Em vista disso, podemos dizer que em temperaturas mais elevadas, como a 900 o C, está ocorrendo a transformação do caulim em metacaulim, sendo esta última fase a mais adequada para tabela 1. 26 Além disso, a grande amorfização estrutural causada pelo aquecimento em altas temperaturas ajuda na formação da zeólita a partir do metacaulim.…”