The invention relates to a process for preparing an AFX-structure zeolite comprising at least the following steps: i) mixing, in an aqueous medium, an FAU-structure zeolite having an SiO.sub.2 (FAU)/Al.sub.2O.sub.3 (FAU) molar ratio of between 2.00 (limit included) and 6.00 (limit excluded), an organic nitrogenous compound R, at least one source of at least one alkali and/or alkaline-earth metal M, the reaction mixture having the following molar composition: (SiO.sub.2 (FAU))/(Al.sub.2O.sub.3 (FAU)) between 2.00 (limit included) and 6.00 (limit excluded), H.sub.2O/(SiO.sub.2 (FAU)) between 1 and 100, R/(SiO.sub.2 (FAU)) between 0.01 and 0.6, M.sub.2/nO/(SiO.sub.2 (FAU)) between 0.005 and 0.7, limits included, until a homogeneous precursor gel is obtained; ii) hydrothermal treatment of said precursor gel obtained on conclusion of step i) at a temperature of between 120° C. and 220° C., for a time of between 12 hours and 15 days.

A catalyst may include a metallic function derived from a metal constrained within cages and/or channels of a microporous material, wherein the cages and/or channels of the microporous material are defined by 8 tetrahedral atoms or fewer; and an acidic function derived from an additional zeolite having cages and/or channels defined by 10 or more tetrahedral atoms, wherein the microporous material providing the metallic function and additional zeolite providing the acidic function are coupled by a binder.

Provided is a beta-type zeolite which has a high catalytic activity and is not easily deactivated.

The beta-type zeolite of the invention has a substantially octahedral shape, has a Si/Al ratio of 5 or more, and is a proton-type zeolite. The Si/Al ratio is preferably 40 or more. This beta-type zeolite is preferably obtained by transforming a raw material beta-type zeolite synthesized without using a structure directing agent into an ammonium-type zeolite through ion exchange, then, exposing the beta-type zeolite to water vapor, and subjecting the exposed beta-type zeolite to an acid treatment.

A zeolite membrane structure includes a porous support, and a zeolite membrane. The zeolite membrane has a first zeolite layer located in a surface of the porous support, and a second zeolite layer located outside of the surface of the porous support and integrally formed with the first zeolite layer. The porous support has an outermost layer in which the first zeolite layer is located. An average thickness of the first zeolite layer is less than or equal to 5.4 micrometers. An average pore diameter of the outermost layer is greater than or equal to 0.050 micrometers and less than or equal to 0.150 micrometers.

The present invention relates to a new chiral zeolite material of composition a SiO.sub.2:b GeO.sub.2:c X.sub.2O.sub.3:d YO.sub.2, with an ITV structure, prepared with a specific chiral organic structure-directing agent, (1S,2S)—N-ethyl-N-methyl-pseudoephedrine or its enantiomer, (1R,2R)—N-ethyl-N-methyl-pseudoephedrine, which means that the material is rich in one of the crystalline forms; a method whereby said material is obtained, and the use thereof in adsorption and catalysis processes.

The present invention relates to a new chiral zeolite material of composition a SiO.sub.2:b GeO.sub.2:c X.sub.2O.sub.3:d YO.sub.2, with an ITV structure, prepared with a specific chiral organic structure-directing agent, (1S,2S)—N-ethyl-N-methyl-pseudoephedrine or its enantiomer, (1R,2R)—N-ethyl-N-methyl-pseudoephedrine, which means that the material is rich in one of the crystalline forms; a method whereby said material is obtained, and the use thereof in adsorption and catalysis processes.

An aluminum-rich molecular sieve material of MFS framework type, designated SSZ-123, is provided. SSZ-123 can be synthesized using 1-ethyl-1-[5-(triethylammonio)pentyl]piperidinium cations as a structure directing agent. SSZ-123 may be used in organic compound conversion and/or sorptive processes.

An aluminum-rich molecular sieve material of MFS framework type, designated SSZ-123, is provided. SSZ-123 can be synthesized using 1-ethyl-1-[5-(triethylammonio)pentyl]piperidinium cations as a structure directing agent. SSZ-123 may be used in organic compound conversion and/or sorptive processes.

A catalyst based on a zeolite of AFX structural type and on at least one transition metal, can be prepared by a process comprising at least the following steps: i) mixing, in an aqueous medium, of at least one source of silicon in oxide form SiO2, of at least one source of aluminium in oxide form Al2O3, of an organic nitrogen-comprising compound R, of at least one source of at least one alkali metal and/or alkaline-earth metal M until a homogeneous precursor gel is obtained; ii) hydrothermal treatment of said precursor gel to obtain a crystallized solid phase, iii) at least one ion exchange with a transition metal; iv) heat treatment. The catalyst can be used for the selective reduction of NOx employing the catalyst, and can achieve an NOx conversion (conversion=(NOx inletNOx outlet)/NOx inlet) of 100% at a temperature of 430 C. or lower.

A system for recovering rare earth elements from coal ash includes a leaching reactor, an ash dryer downstream of the leaching reactor, and a roaster downstream of the ash dryer that is cooperatively connected to both the leaching reactor and the ash dryer. Coal ash is mixed with an acid stream such that rare earth elements present in the coal ash are dissolved in the acid stream, thereby creating (i) a leachate containing the rare earth elements and (ii) leached ash. The leachate is heated to obtain acid vapor and an acid-soluble rare earth concentrate. Mixing of the coal ash with the acid stream can occur in a leaching reactor and heating of the leachate can occur in a roaster. The acid-soluble rare earth concentrate can be fed to a hydrometallurgical process to separate and purify the rare earth elements.