Active material compositions with porous protective sheath and method for preparing
AssigneesFujimi Kenmazai Kogyo Co., Ltd., Mitsubishi Petrochemical Co., Ltd.
InventorsYoshinobu Yamaguchi, Nanahiko Kitano, Yoshihisa Watanabe, Makoto Imanari
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Abstract
A particulate composition composed of a core of active material and a protective sheath having communicating micro pores to permit access of reactants to the active materials is described as well as a method for preparing same.
Claims13
A structurally strong particulate composite of active materials comprising a core and a microporous sheath surrounding said core, said core containing the active material selected from group consisting of catalysts, adsorbants, microsieves, ion exchangers or mixtures thereof in particulate form and said microporous sheath consisting of a solid, strengthening, enclosing structure for said core having an open porous structure including communicating open pores forming passageways for access to said core from the space surrounding said sheathed composite, said porous structure resulting from sintering a sheath-forming material admixed with an organic material that is combustible at sintering temperatures, said sheath-forming material being a crystalline or amorphous inorganic salt or oxide selected from the group consisting of fused alumina, silicon carbide, alumina, silica, zirconia, feldspar, sodium glass, lead glass, borosilicate glass, Portland cement and amorphous alumina cements and said communicating open pores resulting from the combustion of said combustible organic material thereby providing voids comprising said passageways for access to said core from the space surrounding said particulate composite.
The process for preparing particulate composites wherein said active materials are enclosed by a structurally stronger sheath which comprises the steps of
- a. shaping individual cores comprising said active material in particulate form,
- b. coating the cores in the first coat of fugitive material
- c. further coating said cores with a second coat of a coating composition of sheath-forming material comprising
- 1. a structural component of crystalline and amorphous inorganic oxides, salts and mixtures thereof selected from the group consisting of fused alumina, silicon carbide, alumina, silica, zirconia, feldspar, sodium glass, lead glass, borosilicate glass, Portland cement, amorphous alumina cements;
- 2. a binder for said composition component;
- and
- 3. a fugitive component, said fugitive component being selected from among material which are combustible at sintering temperatures;
- d. then forming said second coat into a microporous sheath by heating said coated cores to elevated sintering temperatures thus sintering said second coat around said cores, and also combusting said fugitive material from said first and second coats during said heating step to concurrently form voids in the spaces previously occupied by said fugitive component.
Dependencies are inferred from the claim text.