Résumé
The addition of Mg2+ cations to the synthesis medium of zeolite L favours the zeolite nucleation in the same way as Ag+, an heterogeneous nucleation agent, but slows down crystal growth in the same way as other alkaline earth cations. Comparison with the synthesis of zeolite Y indicates that the promotion of nucleation by Mg2+ is related to the presence of K+ in the synthesis system of zeolite L.