Adsorbent and substrate products and method of producing same
First Claim
1. A composition useful as an adsorbent or substrate comprising about 20%-80% by weight hydrotalcite mixed with about 80%-20% by weight activated alumina, wherein said composition has been activated by heating the hydrotalcite to a temperature of about 500°
- -60020 C. or after mixing with the activated alumina.
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Abstract
Novel adsorbent and substrate compositions are formed by mixing activated aluminas and synthetic hydrotalcite produced by reacting activated magnesia with an aqueous solution containing aluminate, carbonate, and hydroxyl ions. Activated magnesia used in this method is formed by heating a magnesium compound such as magnesium carbonate or magnesium hydroxide to a temperature between about 500°-900° C. The method is suited to producing synthetic hydrotalcite from industrial Bayer liquor. The synthetic hydrotalcite so formed can be heated to a temperature of about 500°-600° C. to form a highly porous and adsorbent product either before or after mixing with activated aluminas to form the composite of the present invention.
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Citations
15 Claims
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1. A composition useful as an adsorbent or substrate comprising about 20%-80% by weight hydrotalcite mixed with about 80%-20% by weight activated alumina, wherein said composition has been activated by heating the hydrotalcite to a temperature of about 500°
- -60020 C. or after mixing with the activated alumina.
- View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method of producing an adsorbent or substrate comprising:
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(a) heating magnesium carbonate or magnesium hydroxide to a temperature in the range of about 500°
-900°
C. to form activated magnesia,(b) reacting said activated magnesia at a temperature of about 80°
-100°
C. with an aqueous alkali solution containing ions of aluminate, carbonate, and hydroxyl comprising 120-250 g/l NaOH (expressed as Na2 CO3), 20-100 g/l Na2 CO3, and 50-150 g/l Al2 O3 to form a synthetic hydrotalcite,(c) mixing said synthetic hydrotalcite with activated alumina, and (d) heating said synthetic hydrotalcite to a temperature of about 500°
-600°
C. before or after said mixing with said activated alumina. - View Dependent Claims (10, 11, 12, 13, 14)
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15. A method of producing an adsorbent product comprising:
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(a) heating magnesium carbonate or magnesium hydroxide to a temperature in the range of about 500°
-900°
C. to form activated magnesia,(b) reacting said activated magnesia with an aqueous solution of industrial Bayer liquor at a temperature of abut 80°
-100°
C. and a pH above about 13, said Bayer liquor containing aluminate, carbonate, and hydroxyl ions present in an amount of 120-250 g/l sodium hydroxide expressed as sodium carbonate, 20-100 g/l sodium carbonate, and 50-150 g/l aluminate,(c) washing and drying said hydrotalcite to form recovered hydrotalcite, (d) heating said recovered hydrotalcite to a temperature in the range of about 500°
-600°
C. to form a porous and adsorbent product,(e) mixing said porous product of hydrotalcite with activated alumina to form an adsorbent mixture, and (f) rehydrating said mixture of hydrotalcite and alumina and forming by pan-type agglomerator, fluidized bed, extruder, or tablet forming apparatus.
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Specification