Gypsum & Lime
Online ISSN : 2185-4351
ISSN-L : 0559-331X
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Volume 1987, Issue 207
Displaying 1-9 of 9 articles from this issue
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  • Structural Analysis of Silicate Anions in Calcium Silicates by Trimethylsilylation Method
    Tamotsu YASUE, Kenichi TANAKA, Yasuo ARAI
    1987 Volume 1987 Issue 207 Pages 65-73
    Published: March 01, 1987
    Released on J-STAGE: March 07, 2011
    DOIhttps://doi.org/10.11451/mukimate1953.1987.65
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    In order to establish the availability of trimethylsilylation (TMS) method, which was applied to change of silicic acid groups having various structures in the formation process of calcium silicates. The results were compared with those of different techniques of X-ray diffraction and infrared spectroscopy.
    The calcium silicates were prepared by heating the mixture of Ca (OH) 2 and SiO2·nH2O of varying Ca/Si atomic ratios of 1/1, 3/2 and 2/1 at 400-1400°C for 3 hours. In the case of Ca/Si atomic ratio of 1/1, it was found from the results obtained by applying the TMS method to formation of low crystalline calcium silicates consisting in ranges of monomer to cyclic tetramer from temperature at 600°C and especially, to presence of Si2O76- ion due to Ca3Si2O7 that did not identified by X-ray diffraction and infrared spectrum. It was confirmed that the heated product above 1100°C must be converted to p-CaSiO3 having low temperature type at room temperature but was stabilized to α-CaSiO3 (Ca3Si3O9) having high temperature type as trimer and existed together Si2O76- ion and SiO44- ion due to β-Ca2SiO4. In the formation process of Ca/Si atomic ratio of 2/1, the heated product showed the formation of monomer to cyclic tetramer at temperature above 600°C but finally changed to SiO44- ion. The above results obtained by Lentz's method were partially compared with those of Masson's method.
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  • Microstructure and Strength Development of Akermanite by Hydrothermal Reaction
    Kiyoshi ASAGA, Jun TANABE, Masaki DAIMON, Kyung Hee LEE
    1987 Volume 1987 Issue 207 Pages 74-81
    Published: March 01, 1987
    Released on J-STAGE: March 07, 2011
    DOIhttps://doi.org/10.11451/mukimate1953.1987.74
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    Authors investigated microstructure and strength development during the hydrothermal reaction of akermanite (Ca2MgSi2O7) at 210°C and 350°C under saturated steam pressure.
    1) Antigorite (Mg3Si2O5 (OH) 4) was formed as the main crystalline phase of produced magnesium silicate hydrate from akermanite. Talc (Mg3Si4O10 (OH) 2) was the main crystalline phase when quartz was co-existed. These magnesium silicate hydrates increased the strength development.
    2) The strength of hydrothermally treated akermanite was weak because of the slow rate of reaction. The strength of the samples with Ca (OH) 2 did not increase in spite of the proceeding reaction. Mg (OH) 2 was formed, in this case, instead of magnesium silicate hydrates.
    3) The best strength development was achieved when quartz was co-existed. The microstructure was very fine by the production of magnesium silicate hydrate and calcium silicate hydrate such as xonotlite (Ca6Si6O17 (OH) 2).
    4) The system of akermanite-quartz seemed to be suitable for geothermal well cement.
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  • Size and Shape Effects of Coating Powders on the Fluidabilities and Caking Properties of Granular Detergent
    Osamu OKUMURA, Ryuichi NAKAGAWA, Yasuo TSURUTA
    1987 Volume 1987 Issue 207 Pages 82-87
    Published: March 01, 1987
    Released on J-STAGE: March 07, 2011
    DOIhttps://doi.org/10.11451/mukimate1953.1987.82
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    Blending effects of fine calcium sulfite and calcium carbonate with different particle size and shape on the laundry granular detergent has been studied in the basis of fluidability and property of caking.
    When the particle sizes of calcium sulfite and calcium carbonate are in the range of 1 to 2μm in average diameter, fluidabilities of the granular detergents are obtained in the desired level without any caking of the granular detergent even in the hot and high humid conditions. Fluidabilities and properties of caking are also effectively affected by the particle shapes of calcium sulfite and calcium carbonate.
    The powders characterized by cubic in shapes are more useful for improving the fluidability and the properties of caking in granular laundry detergent.
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  • Synthesis of 3CaO·Al2O3·6H2O in Aqueous Solution under the Atmospheric Pressure and Rehydration of Their Thermal Decomposition Products
    Hiroyuki SANGO, Tsugio MIYAKAWA
    1987 Volume 1987 Issue 207 Pages 88-98
    Published: March 01, 1987
    Released on J-STAGE: March 07, 2011
    DOIhttps://doi.org/10.11451/mukimate1953.1987.88
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    Tricalcium aluminate hexahydrate (3CaO-Al2O3·6H2O or C3AH6) is known as a stable phase which is generally formed by hydration of anhydrous calcium aluminate.
    Synthesis of C3AH6 from calcium hydroxide and aluminium hydroxide was investigated. The starting mixture was heated at various temperatures in aqueous solutions under the atmospheric pressure. Thermal dehydration of synthesized C3AH6 was studied by means of an X-ray diffractometer and a scanning electron microscope. The rehydration process of heat-treated C3AH6 was observed. The results obtained are as follows :
    (1) C3AH6 can be obtained from a mixture of calcium hydroxide and aluminium hydroxide below 100°C in aqueous solutions under the atmospheric pressure.
    (2) During the synthesis of C3AH6, a mixture of calcium hydroxide and aluminium hydroxide in aqueous solutions should not be exposed to air containing carbon dioxide.
    (3) At about 300°C, C3AH6 is decomposed to C12A7H and calcium hydroxide. Calcium hydroxide is dehydrated into calcium oxide at 400°C. At temperature above 1000°C, C12A7H (or C12A7) and calcium oxide recombine to form C3A.
    (4) C12A7H containing calcium hydroxide (C12A7H*) which is prepared by decomposition of C3AH6 accelerates the setting of ordinary portland cement (O. P. C.), but it decreases the compressive strength of it.
    (5) The early strengths of O. P. C. are increased by adding mixtures of C12A7H* and anhydrous gypsum II.
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  • Erratum to : Gypsum and Lime Concerning Industrial Waste
    1987 Volume 1987 Issue 207 Pages 98d
    Published: 1987
    Released on J-STAGE: March 07, 2011
    DOIhttps://doi.org/10.11451/mukimate1953.1987.207_98d
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  • Erratum
    1987 Volume 1987 Issue 207 Pages 98a
    Published: 1987
    Released on J-STAGE: March 07, 2011
    DOIhttps://doi.org/10.11451/mukimate1953.1987.207_98a
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  • Erratum to : Synthesis of Hexagonal Plate-like Crystal of Calcium. Hydroxide by Hydration of Calcium Oxide
    1987 Volume 1987 Issue 207 Pages 98b
    Published: 1987
    Released on J-STAGE: March 07, 2011
    DOIhttps://doi.org/10.11451/mukimate1953.1987.207_98b
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  • Erratum to : Ion Exchange Behavior of the Initial Product in the Synthesis of Zeolite A
    1987 Volume 1987 Issue 207 Pages 98c
    Published: 1987
    Released on J-STAGE: March 07, 2011
    DOIhttps://doi.org/10.11451/mukimate1953.1987.207_98c
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  • Preparation of Ultrafine Powders
    Seisiro ITO
    1987 Volume 1987 Issue 207 Pages 99-105
    Published: March 01, 1987
    Released on J-STAGE: March 07, 2011
    DOIhttps://doi.org/10.11451/mukimate1953.1987.99
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