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Publication numberUSRE34164 E
Publication typeGrant
Application numberUS 07/650,730
Publication dateJan 19, 1993
Filing dateFeb 4, 1991
Priority dateMar 30, 1974
Fee statusPaid
Publication number07650730, 650730, US RE34164 E, US RE34164E, US-E-RE34164, USRE34164 E, USRE34164E
InventorsChanakya Misra
Original AssigneeAluminum Company Of America
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Synthetic hydrotalcite
US RE34164 E
Abstract
Disclosed is a method for producing hydrotalcite in high yield including reacting activated magnesia with an aqueous solution containing aluminate, carbonate, and hydroxyl ions. The .[.method further includes a first step of.]. .Iadd.activated magnesia is produced by .Iaddend.heating magnesium carbonate or magnesium hydroxide to a temperature between about 500-900 C. .[.to form activated magnesia or magnesium oxide..]. The method is suited to producing synthetic hydrotalcite from industrial Bayer liquor.
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Claims(17)
What is claimed is:
1. A method of producing hydrotalcite, comprising:
(a) heating magnesium carbonate or magnesium hydroxide to a temperature between about 500-900 C. to form activated magnesia; and
(b) reacting activated magnesia with an aqueous solution of aluminate, carbonate, and hydroxyl ions at a pH above about 13 to form hydrotalcite at a conversion yield greater than about 75%.
2. A method as set forth in claim 1 wherein said solution comprises a Bayer liquor.
3. A method as set forth in claim 1 wherein said reacting includes heating to a temperature of at least about 80 C. at ambient pressure.
4. A method as set forth in claim 1, said first step comprising heating magnesium carbonate or magnesium hydroxide to a temperature between about 550-650 C. to form said activated magnesia.
5. A method as set forth in claim 4 wherein said magnesium carbonate or magnesium hydroxide is heated to a temperature between about 550-650 C. for a period of about 30 to 120 minutes.
6. A method as set forth in claim 1 wherein said aqueous solution containing ions of aluminate, carbonate, and hydroxyl comprises about 120-250 grams/liter NaOH (expressed as Na2 CO3), about 20-100 grams/liter NaCO3, and about 50.150 grams/liter Al2 O3.
7. A method as set forth in claim 6 wherein about 5-25 grams/liter activated magnesia is added to said aqueous solution.
8. A method of producing a material having a powder X-ray diffraction pattern of the mineral hydrotalcite comprising:
(a) heating magnesium carbonate or magnesium hydroxide to a temperature between about 500-900 C. to form activated magnesia; and
(b) reacting said activated magnesia with an aqueous solution of aluminate, carbonate, and hydroxyl ions at a pH above 13 to from hydrotalcite at a conversion yield greater than about 75%.
9. A method as set forth in claim 8 wherein said aqueous solution comprises an industrial Bayer liquor.
10. A method as set forth in claim 9 wherein said reacting comprises heating to a temperature of at least about 80 C. at atmospheric pressure.
11. A method as set forth in claim 10 said first step comprising heating magnesium carbonate or magnesium hydroxide to a temperature between about 550-650C. to form said activated magnesia.
12. A method as set forth in claim 11 further comprising recovering said hydrotalcite in dried form. .Iadd.
13. A method of producing hydrotalcite comprising:
reacting activated magnesia produced by heating magnesium carbonate or magnesium hydroxide to between about 500-900 C. with an aqueous solution containing aluminate, carbonate and hydroxyl ions at a pH above about 13 to form hydrotalcite at a conversion yield greater than about 75%. .Iaddend. .Iadd.14. A method as set forth in claim 13 wherein said solution comprises a Bayer liquor. .Iaddend. .Iadd.15. A method as set forth in claim 13 wherein said reacting includes heating to a temperature of at least about 80 C. at ambient pressure. .Iaddend. .Iadd.16. A method as set forth in claim 13 wherein said magnesium carbonate or magnesium hydroxide is produced by heating to a temperature between about 550-650 C. to form said activated magnesia. .Iaddend. .Iadd.17. A method as set forth in claim 16 wherein said magnesium carbonate or magnesium hydroxide is produced by heating to a temperature between about 550-650 C. for a period of about
30 to 120 minutes. .Iaddend. .Iadd.18. A method of producing a material having a powder X-ray diffraction pattern containing the mineral hydrotalcite comprising:
reacting activated magnesia produced by heating magnesium carbonate or magnesium hydroxide to a temperature between about 500-900 C. with an aqueous solution of aluminate, carbonate, and hydroxyl ions at a pH above about 13 to form hydrotalcite at a conversion yield greater than about 75%. .Iaddend. .Iadd.19. A method as set forth in claim 18 wherein said aqueous solution comprises an industrial Bayer liquor. .Iaddend. .Iadd.20. A method as set forth in claim 19 wherein said reacting comprises heating to a temperature of at least about 80 C. at atmospheric pressure. .Iaddend. .Iadd.21. A method as set forth in claim 20 wherein said magnesium carbonate or magnesium hydroxide is produced by heating to a temperature between about 550-650 C. to form said activated magnesia. .Iaddend. .Iadd.22. A method as set forth in claim 18 further comprising recovering said hydrotalcite in dried
form. .Iaddend. .Iadd.23. A method of producing hydrotalcite comprising reacting activated magnesia produced by heating magnesium carbonate or magnesium hydroxide to between about 500 and 900 C. with an aqueous solution containing aluminate, carbonate and hydroxyl ions to form hydrotalcite at a conversion yield greater than about 75%. .Iaddend. .Iadd.24. A method as set forth in claim 23 wherein about 5.25 grams of activated magnesia is added per liter of aqueous solution to said aqueous solution. .Iaddend. .Iadd.25. A method as set forth in claim 23 wherein said aqueous solution containing ions of aluminate, carbonate and hydroxyl ions comprises about 120 to 250 grams per liter of NaOH (expressed as Na2 CO3). .Iaddend. .Iadd.26. A method as set forth in claim 23 wherein said aqueous solution containing ions of aluminate, carbonate and hydroxyl ions comprises about 20 to 100 grams per liter of Na2 CO3. .Iaddend. .Iadd.27. A method as set forth in claim 23 wherein said aqueous solution containing ions of aluminate, carbonate and hydroxyl ions comprises about 50 to 150 grams per liter of Al2 O3. .Iaddend. .Iadd.28. A method as set forth in claim 23 wherein said aqueous solution containing ions of aluminate, carbonate and hydroxyl ions comprises about 120 to 250 grams per liter of NaOH (expressed as Na2 CO3) and about 20 to 100 grams per liter of Na2 CO3.
.Iaddend. .Iadd.29. A method as set forth in claim 23 wherein said aqueous solution containing ions of aluminate, carbonate and hydroxyl ions comprises about 20 to 100 grams per liter of Na2 CO3 about 50 to 150 grams per liter of Al2 O3. .Iaddend. .Iadd.30. A method as set forth in claim 23 wherein said aqueous solution containing ions of aluminate, carbonate and hydroxyl ions comprises about 120 to 250 grams per liter of NaOH (expressed as Na2 CO3) and about 50 to 150 grams per liter of Al2 O3. .Iaddend. .Iadd.31. A method as set forth in claim 23 wherein said aqueous solution containing ions of aluminate, carbonate and hydroxyl ions comprises about 120 to 250 grams per liter of NaOH (expressed as Na2 CO3), about 20 to 100 grams per liter of Na2 CO3 about 50 to 150 grams per liter of Al2 O3. .Iaddend. .Iadd.32. A method as set forth in claim 23 wherein said aqueous solution containing ions of aluminate, carbonate and hydroxyl ions comprises up to about 100 grams per liter of Na2 CO3. .Iaddend. .Iadd.33. A method as set forth in claim 23 wherein said aqueous solution containing ions of aluminate, carbonate and hydroxyl ions comprises up to about 150 grams per liter of Al2 O3. .Iaddend. .Iadd.34. A method as set forth in claim 23 wherein said aqueous solution containing ions of aluminate, carbonate and hydroxyl ions comprises up to
about 250 grams per liter of NaOH. .Iaddend. .Iadd.35. A method as set forth in claim 23 wherein at least 5 grams of activated magnesia is added per liter of said aqueous solution. .Iaddend.
Description
CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation-in-part of U.S. patent application Ser. No. 595,374, filed Mar. 30, 1984, now abandoned.

BACKGROUND OF THE INVENTION

This invention relates to a method for producing synthetic hydrotalcite.

Hydrotalcite is a naturally occurring mineral having the formula 6 MgO.Al2 O3.CO2.12 H2 O or Mg6 Al2 (OH)16 CO3.4 H2 O. Known deposits of natural hydrotalcite are very limited and total only about 2,000 or 3,000 tons in the whole world. Natural hydrotalcite has been found in Snarum, Norway and in the Ural Mountains. Typical occurrences are in the form of serpentines, in talc schists, and as an alteration product of spinel where, in some cases, hydrotalcite has formed as pseudomorphs after spinel.

The upper stability temperature of hydrotalcite is lower than the lower limit for spinel. Spinel and hydrotalcite theoretically never would appear together in stable condition. If equilibrium has been established, the spinel would be completely changed to hydrotalcite. However, naturally occurring hydrotalcite is intermeshed with spinel and other materials.

Natural hydrotalcite is not present as pure product and always contains other minerals such as penninite and muscovite and potentially undesirable minerals such as heavy metals. Conventional practice recognizes that it is practically impossible to remove such impurities from a natural hydrotalcite.

Previous attempts to synthesize hydrotalcite have included adding dry ice or ammonium carbonate (a) to a mixture of magnesium oxide and alpha-alumina or (b) to a thermal decomposition product from a mixture of magnesium nitrate and aluminum nitrate and thereafter maintaining the system at temperatures below 325 C. at elevated pressures of 2,000-20,000 psi. Such a process is not practical for industrial scale production of synthetic hydrotalcite by reason of the high pressures. Furthermore, the high pressure process forms substances other than hydrotalcite, such as brucite, boehmite, diaspore, and hydromagnesite.

Ross and Kodama have reported a synthetic mineral prepared by titrating a mixed solution of MgCl2 and AlCl3 with NaOH in a CO2 free system and then dialyzing the suspension for 30 days at 60 C. to form a hydrated Mg-Al carbonate hydroxide. The mineral product has been associated with the formula Mg6 Al2 CO3 (OH)16.4 H2 O while having the properties of manasseite and hydrotalcite. X-ray diffraction powder patterns have indicated that the mineral more closely resembles manasseite than hydrotalcite, while the differential thermal analysis curve of the precipitate has been characterized as similar to that given for hydrotalcite.

Kerchle, U.S. Pat. No. 4,458,026, discloses a preparation of Mg/Al/carbonate hydrotalcite which involves the addition of mixed magnesium/aluminum nitrates, sulphates or chlorides as an aqueous solution to a solution of a stoichiometric amount of sodium hydroxide and carbonate at about 25-35 C. with stirring over a several-hour period producing a slurry. The slurry is then heated for about 18 hours at about 50-200 C. (preferably 60-75 C.) to allow a limited amount of crystallization to take place. After filtering the solids, and washing and drying, the dry solids are recovered.

Kumura et al. U.S. Pat. No. 3,650,704, reports a synthetic hydrotalcite preparation by adding an aqueous solution of aluminum sulfate and sodium carbonate to a suspension of magnesium hydroxide. The suspension then can be washed with water until the presence of sulfate radical becomes no longer observable. The suspension is heated at 85 C. for three hours and dried. The magnesium component starting material is reported as any member of the group consisting of magnesium oxide, magnesium hydroxide, magnesium carbonate, and water-soluble magnesium salts, e.g., such as mineral acid salts including magnesium chloride, magnesium nitrate, magnesium sulfate, magnesium dicarbonate, and bittern.

It is an object of the present invention to produce synthetic hydrotalcite in high purity.

It is another object of this invention to produce hydrotalcite in high yield at atmospheric pressure.

SUMMARY OF THE INVENTION

The present invention includes a method for producing hydrotalcite including reacting an activated magnesia with an aqueous solution of aluminate, carbonate, and hydroxyl ions. The method can be carried out at atmospheric pressure to form hydrotalcite in high purity and high yield. Activated magnesia is formed by heating a magnesium compound such as magnesium carbonate or magnesium hydroxide to a temperature between about 500-900 C.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a graphical depiction of a powder X-ray diffraction pattern obtained from synthetic hydrotalcite produced by the method of the present invention.

FIG. 2 is a graphical depiction of the differential thermal analysis of synthetic hydrotalcite obtained by the method of the present invention.

FIG. 3 is a photographic representation of synthetic hydrotalcite obtained by the method of the present invention.

DETAILED DESCRIPTION

The present invention produces synthetic hydrotalcite by reacting activated magnesia with an aqueous solution of aluminate, carbonate, and hydroxyl ions. The magnesia must be activated to produce hydrotalcite in high purity. Otherwise, i.e., in the event that an unactivated magnesia is used, the resulting product will include substantial amounts of mineral forms other than hydrotalcite.

The activated magnesia can be formed by activating magnesium compounds such as magnesium carbonate or magnesium hydroxide at temperatures of between about 500-900 C. Below 500 C., the magnesium salt will not activate sufficiently and will contain inhibiting amounts of the starting material. Above 900 C., the resulting magnesium oxide takes on a form which is insufficiently active. The insufficiently active magnesia could be characterized as dead burnt. Such a form of magnesia will not form hydrotalcite predominantly over other mineral forms. The insufficiently active form of magnesia which is nonspecific to forming hydrotalcite will be avoided by heating the magnesium salt starting materials to elevated activating temperatures, but which must not exceed about 900 C., to form the activated magnesia or magnesium oxide (MgO).

The activated magnesium oxide is added to a solution containing ions of aluminate, carbonate, and hydroxl. Preferably the activated magnesium oxide is added to an aqueous solution having a pH above about 13. For example, a suitable solution may contain alkali hydroxide, alkali carbonate, and aluminum oxide. Industrial Bayer process liquor used for the production of alumina from bauxite is a suitable solution containing sodium hydroxide, sodium carbonate, and aluminate ions. A Bayer process liquor containing excess alumina also is suitable.

By way of example, 5-25 grams per liter of activated MgO can be added to 120-250 g/l NaOH (expressed as Na2 CO3), 20-100 g/l Na2 CO3, and 50-150 g/l Al2 O3 in an aqueous solution. The mixture should be agitated at a temperature of about 80-100 C. for 20-120 minutes.

It has been found that magnesium compounds other than the activated magnesia of the present invention produce less than desirable results. For example, MgSO4, MgCl2, or MgNO3 added to Bayer liquor yields Mg(OH)2 and Al(OH)3. Similarly, Mg(OH2 added to Bayer liquor remains mostly unreacted.

The process of the present invention produces hydrotalcite in high yield. By high yield is meant a conversion yield greater than about 75% and preferably greater than about 90%.

The mineral produced by the method of the present invention can be analyzed by powder X-ray diffraction. The product formed by Example 2 of this specification was analyzed in powder form in a Siemens X-ray diffractometer having Model No. D-500 supplied by Siemens AG (W. Germany). The resulting X-ray diffraction pattern is depicted in FIG. 1. The diffraction pattern indicates that the product is hydrotalcite at high purity. The dÅ spacing obtained by X-ray diffraction is shown in Table I for the mineral obtained from the method of Example 2 and is compared to (1) the ASTM standard for hydrotalcite and (2) natural hydrotalcite as reported by Roy et al. American Journal of Science, Vol. 251, at page 353. By these indications, the process of the present invention produces hydrotalcite in high purity.

High purity in the context of the present invention is established by the absence of diffraction lines attributable to compounds other than hydrotalcite. The absence of diffraction lines indicates that such other compounds are not present in any significant amount. By way of contrasting example, the material produced in Example 1 described hereinbelow using a non-activated magnesium oxide contains lines or peaks indicating the presence of compounds other than hydrotalcite. These lines are observed in the data in Table I for the dÅ spacing of the product from Example 1.

              TABLE I______________________________________X-RAY DIFFRACTION   Natural   HydrotalciteASTM    (Snarum,(22-700)   Norway)     Example 1    Example 2I/I            I/I          I/I         I/IdÅMax.   dÅ  Max.  dÅ Max.  dÅ                                        Max.______________________________________7.84 100    7.63    100   12.4676                            4.3   8.8729                                        3.73.90 60     3.82    50    12.3128                            4.8   7.7348                                        99.22.60 40     2.56    10    12.1094                            4.2   7.6746                                        100.02.33 25     2.283    5    11.8579                            5.5   6.0944                                        5.01.99030     1.941   10    11.5907                            4.2   6.0194                                        4.71.950 6     1.524    5    11.3070                            4.7   5.9257                                        5.91.54135     1.495    5    11.1268                            4.2   4.0786                                        8.61.49825                   10.9421                            4.2   3.9498                                        30.01.419 8                   10.5889                            4.1   3.8387                                        60.91.302 6                   4.7678 45.7  3.8192                                        64.51.26510                   4.6131 6.9   2.6644                                        4.01.172 2                   4.5742 6.0   2.5765                                        80.10.994 4                   4.5429 3.9   2.5204                                        25.20.976 6                   4.5093 5.3   2.5102                                        21.7                     4.4645 4.9   2.4960                                        14.9                     4.4154 3.3   2.4840                                        13.0                     4.3161 3.3   2.4643                                        10.8                     4.2944 3.0   2.4526                                        11.4                     4.2552 3.2   2.4364                                        10.0                     4.2163 5.9   2.0677                                        3.7                     4.1814 5.4   2.0530                                        5.7                     4.1349 7.4   2.0477                                        3.3                     4.1009 6.9   2.0467                                        3.9                     4.0676 9.7   2.0401                                        4.9                     3.9759 13.9  2.0318                                        7.4                     2.7284 5.4   2.0221                                        6.7                     2.6458 4.1   2.0191                                        6.6                     2.5774 30.4  2.0041                                        12.4                     2.4920 7.3   1.9976                                        10.3                     2.4800 6.6   1.5239                                        38.8                     2.4660 8.0   1.5115                                        18.4                     2.4372 19.9  1.4963                                        34.1                     2.3703 100.0 1.3209                                        2.0                     2.3191 15.5  1.3180                                        2.8                     2.2869 17.1  1.3161                                        4.1                     1.9616 5.2   1.3114                                        4.1                     1.9465 9.7   1.3099                                        3.3                     1.9372 8.3   1.2771                                        4.1                     1.9302 8.2   1.2722                                        5.2                     1.9244 7.3   1.2692                                        4.3                     1.8194 5.0   1.2689                                        5.6                     1.7953 27.1  1.2662                                        6.8                     1.5740 29.2  1.2632                                        4.1                     1.5614 3.0                     1.5557 4.2                     1.5347 4.7                     1.5225 18.2                     1.5102 7.9                     1.4918 87.7                     1.3745 4.9                     1.3719 5.2                     1.3692 3.0                     1.3176 2.2                     1.3121 7.8                     1.3089 8.4______________________________________

The product of Example 2 was analyzed by differential thermal analysis (DTA). FIG. 2 presents a graphical illustration of the DTA for the product of Example 2 which represents hydrotalcite in a high purity.

The synthetic hydrotalcite produced by the present invention is a highly porous mineral. A photograph by scanning electron micrograph was taken of the product of the process carried out in Example 2 and is presented as FIG. 3. The photograph illustrates the mineral product at a 5,000X magnification. The mineral can be seen to have a high surface area and high porosity.

Synthetic hydrotalcite produced by the process of the present invention has utility in one aspect in purification applications such as a filter aid. The synthetic hydrotalcite is adaptable in other aspects as a fire retardant material which releases water and CO2 on heating. Other applications include a filler material for paper or as a drying, bleaching, or absorbent material after activation by heating to over about 500 C. Synthetic hydrotalcite produced by the process of the present invention also is useful in purification and catalytic applications by virtue of an anion exchange capability wherein carbonate anion can be replaced with other anions without destroying the structure of the compound.

EXAMPLE 1

Magnesium carbonate in an amount of 25 grams was heated to about 1,100 C. for about 45 minutes and allowed to cool. The resulting magnesium oxide was added to a Bayer liquor prepared by digesting Suriname bauxite in a ratio of about 0.65 (defined as Al2 O3 /caustic expressed as Na2 CO3 as used in industrial practice) at blow off and then filtered. One liter of Bayer liquor was heated to about 95 C. Ten grams of the magnesium compound treated at 1,100 C. were added. The mixture was agitated for one-half hour and then filtered. The residue was washed and dried at 105 C. overnight.

The resulting product weighed about 16.7 grams which indicates a yield of less than 67%. The product of this Example 1 was analyzed by powder X-ray diffraction and was found to contain predominant amounts of Mg(OH)2 and MgO.

EXAMPLE 2

Activated magnesia was produced by heating 25 grams magnesium carbonate to about 600 C. for 45 minutes. The heating period of 45 minutes was selected to facilitate complete activation. For varying amounts and temperatures, the heating period should be adjusted to achieve an active product. Typical heating periods will range from about 30 to about 120 minutes.

Ten grams of the activated MgO were added to one liter of the same Bayer liquor used in Example 1. The mixture was heated to about 95 C. and agitated for about one-half hour. The mixture was filtered, and the residue was washed and dried at 105 C. overnight. The resulting precipitate had a white appearance, weighed about 22.5 grams, and had a refractive index of 1.50. The precipitate was a fine, free-flowing crystalline powder insoluble in water and organic solvents.

The precipitate was analyzed by powder X-ray diffraction and found to be hydrotalcite in high purity.

The 22.5 grams compares to a theoretical yield of 24.95 grams and indicates a high yield conversion of over 90%.

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US201208 *Jan 25, 1878Mar 12, 1878 Improvement in trace trimming and creasing machines
US3320029 *Dec 21, 1964May 16, 1967 Method of preparing magnesia
US3539306 *Jul 21, 1967Nov 10, 1970Kyowa Chem Ind Co LtdProcess for the preparation of hydrotalcite
US3650704 *Jan 6, 1970Mar 21, 1972Hasui KatuyukiNovel synthetic hydrotalcite and antacid comprising said synthetic hydrotalcite
US3796792 *Dec 8, 1970Mar 12, 1974Kyowa Chem Ind Co LtdComposite metal hydroxides
US3879523 *Dec 8, 1970Apr 22, 1975Kyowa Chem Ind Co LtdComposite metal hydroxides
US4046855 *Apr 14, 1976Sep 6, 1977Gebruder Giulini GmbhMethod for removing harmful organic compounds from aluminate liquors of the Bayer process
US4145400 *Apr 12, 1977Mar 20, 1979Imperial Chemical Industries LimitedCoprecipitation salts of aluminum and cobalt or nickel with sodium carbonate
US4229309 *Jul 18, 1977Oct 21, 1980Petrolite CorporationMagnesium-containing dispersions
US4351814 *Dec 18, 1980Sep 28, 1982Kyowa Chemical Industry Co., Ltd.Hydrotalcites having a hexagonal needle-like crystal structure and process for production thereof
US4443433 *Nov 1, 1982Apr 17, 1984Warner-Lambert CompanyAntacid material based on magnesium aluminum hydroxide and preparation thereof
US4447417 *Feb 15, 1979May 8, 1984Anphar S.A.Basic aluminium magnesium carbonate
US4482542 *Jul 12, 1983Nov 13, 1984Warner-Lambert CompanyAntacid material based on magnesium aluminium hydroxide and the preparation thereof
US4539195 *Feb 23, 1984Sep 3, 1985Giulini Chemie GmbhAntacides
US4560545 *Mar 5, 1984Dec 24, 1985Anphar S.A.Basic aluminum magnesium carbonate
US4591633 *Jul 8, 1985May 27, 1986Chisso CorporationMixing with inorganic double salts, or calcined products or hydrates thereof
US4593343 *Nov 5, 1984Jun 3, 1986Sprague Electric CompanyElectrolytic capacitor and spacer therefor
US4642193 *Jan 25, 1985Feb 10, 1987Kyowa Chemical Industry Co. Ltd.Ion exchanging with hydrotalcite
US4735987 *Jun 30, 1986Apr 5, 1988Osaka Yuki Kagaku Kogyo Kabushiki KaishaMethod for manufacture of high-expansion type absorbent polymer
US4774212 *Dec 22, 1987Sep 27, 1988Amoco CorporationPillared hydrotalcites
US4915930 *Nov 23, 1988Apr 10, 1990Aluminum Company Of AmericaProcess for producing aluminum hydroxide of improved whiteness
Non-Patent Citations
Reference
1"Synthesis of Hydrotalcite-Like Compounds & Their Physicochemical Properties . . . ", Clay & Clay Minerals, vol. 25, pp. 14-18, 1977.
2"Synthesis of New Hydrotalcite-Like Compunds & Their Physico Chemical Properties . . . ", Chemistry Letters, pp. 843-848, 1973.
3 *Hand Book of Chemical Synonyms & Trade Names, 1978, p. 365.
4 *Neoformation of Hydrotalcite Due to Industrial Inputs in Marine Sediments, American Mineralogist, vol. 62, pp. 1173 1179, 1977, Stoffyn et al.
5Neoformation of Hydrotalcite Due to Industrial Inputs in Marine Sediments, American Mineralogist, vol. 62, pp. 1173-1179, 1977, Stoffyn et al.
6 *Physico Chemical Properties of Synthetic Hydrotalcites in Relation to Composition Clay and Clay Minerals, vol. 28, 1, pp. 50 56, 1980.
7Physico-Chemical Properties of Synthetic Hydrotalcites in Relation to Composition Clay and Clay Minerals, vol. 28, #1, pp. 50-56, 1980.
8 *Properties of a Synthetic Magnesium Aluminum Carbonate Hydroxide and its Relationship to Magnesium Aluminum Double Hydroxide Manasseite and Hydrotalcite, The American Mineralogist, vol. 52, Jul., Aug. 1967.
9 *Synthesis of Hydrotalcite Like Compounds & Their Physicochemical Properties . . . , Clay & Clay Minerals, vol. 25, pp. 14 18, 1977.
10 *Synthesis of New Hydrotalcite Like Compunds & Their Physico Chemical Properties . . . , Chemistry Letters, pp. 843 848, 1973.
11 *The Syntheses of Hydrotalcite like Compouds & Their Structures & Physico Chemical Properties, Clay & Clay Minerals, vol. 23, pp. 369 375, 1975.
12The Syntheses of Hydrotalcite-like Compouds & Their Structures & Physico Chemical Properties, Clay & Clay Minerals, vol. 23, pp. 369-375, 1975.
13 *The System MgO Al 2 O 3 H 2 O & The Influence of Carbonate and Nitrate Ions on the Phase Equilibria, American Journal of Science, vol. 251, pp. 337 361, May 1953.
14The System MgO--Al2 O3 --H2 O & The Influence of Carbonate and Nitrate Ions on the Phase Equilibria, American Journal of Science, vol. 251, pp. 337-361, May 1953.
Referenced by
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US5474715 *Sep 9, 1993Dec 12, 1995Tdk CorporationPhotochromic material, photochromic thin film, clay thin film, and their preparation
US5514361 *Apr 29, 1994May 7, 1996Aluminum Company Of AmericaMagnesium aluminum hydroxide hydrates, reduced carbonate contamination
US5624646 *Feb 2, 1995Apr 29, 1997Aluminum Company Of AmericaMethod for improving the brightness of aluminum hydroxide
US5645810 *Jun 7, 1995Jul 8, 1997Aluminum Company Of AmericaHigh surface area meixnerite from hydrotalcites
US5750453 *Dec 20, 1996May 12, 1998Aluminum Company Of AmericaHigh surface area meixnerite from hydrotalcites infiltrated with metal salts
US5843862 *Oct 25, 1996Dec 1, 1998Amoco CorporationProcess for manufacturing an absorbent composition
US5882622 *Apr 9, 1997Mar 16, 1999Aluminum Company Of AmericaCarbon dixide adsorption of synthetic meixnerite
US6322885 *Dec 13, 2000Nov 27, 2001Isela Laminate Systems Corp.Mixture containing talc; dustless
US6803401Sep 21, 2001Oct 12, 2004Reheis, Inc.Including a hydrotalcite (a basic aluminum-magnesium carbonate) to provide corrosion resistance and discoloration inhibition to halogen-containing addition polymers containing catalytic titanium tetrachloride residue
WO1995029874A1 *Jan 6, 1995Nov 9, 1995Aluminum Co Of AmericaSynthetic meixnerite product and method
WO1996005140A1 *Jan 6, 1995Feb 22, 1996Aluminum Co Of AmericaTwo powder synthesis of hydrotalcite and hydrotalcite-like compounds
Classifications
U.S. Classification423/115, 423/179, 423/630, 423/430, 423/420.2, 423/600, 424/686
International ClassificationC01F7/00, C01F5/02
Cooperative ClassificationC01P2004/03, C01P2002/72, C01F5/02, C01P2002/88, C01F7/005, C01P2002/22
European ClassificationC01F7/00D2H, C01F5/02
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