| 摘要 |
<p>The production of an agglomerated zeolite comprising at least 95% zeolite X, with a silicon/aluminium ratio of 1, exchanged with lithium, comprises: (a) submitting low silicon X (LSX) zeolites to one or more successive exchanges with a lithium chloride (LiCl) solution at 100 degrees C, and optionally to exchange of exchangeable cation sites with ions of groups 1A, IIA, IIIA and IIIB, trivalent lanthanide or rare earth ions, Zn(II), Cu(II), Cr(III) Fe(III), NH4<+> and/or hydronium ion, preferably calcium, strontium, zinc and rare earths; (b) washing the exchanged material several times; and (c) drying and thermally activating the washed product. The LSX zeolites are obtained by: (i) agglomeration of an LSX powder with a binder containing at least 80% of a zeolitisable clay; (ii) forming of the mixture; (iii) drying, then calcining at 500-700 degrees C, preferably 500-600 degrees C; (iv) contacting of the resulting product with an aqueous (at least 0.5M) caustic solution; and (v) washing, drying and activation at 300-600 degrees C, preferably 500-600 degrees C, without producing any hydrothermal degradation of the zeolite structure.</p> |
