Preparation of small analcime particles with narrow size distributions from acid-treated larger analcime particles

Narrowly size distributed analcime particles of 0.38–3.7 μm were hydrothermally synthesized from alkaline synthesis mixtures containing seeds of acid-treated larger analcime particles (25 ± 4.2 μm). Treatment of the larger particles with dilute HCl (∼0.5 N) led to fine cracking as aluminium dissolved; more concentrated HCl (>3.0 N) led to larger cracks and particles’ breaking. The acid-treated analcime particles dissociated into small zeolite domains in the alkaline synthesis mixture and acted as seeds to grow analcime particles. Seeds prepared with 1.0 N HCl grew into analcime particles of 0.38 ± 0.03 μm; the use of 4.0 N HCl resulted in analcime particles of 2.7 ± 0.07 μm. The analcime particles’ sizes could be controlled through the concentration of HCl used in the preparation of the seeds. Narrow particle size distributions arose due to the seeds in the synthesis mixtures and the rapid hydrothermal growth of analcime particles.

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► Production of uniformly sized seeds by acid treatment of large analcime particles.
► Synthesis of small analcime particles with narrow size distributions.
► Particles’ sizes could be controlled between 0.38 and 3.7 μm.