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Volume 1983, Issue 182
Displaying 1-6 of 6 articles from this issue
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Tamotsu YASUE, Norifumi NAGATA, Isamu KISHIDA, Yasuo ARAI1983 Volume 1983 Issue 182 Pages 3-11
Published: January 01, 1983
Released on J-STAGE: March 07, 2011
JOURNAL FREE ACCESSCalcium sulfite hemihydrate (CaSO3.1 /2H2O) was prepared by passing SO2 gas through a suspension of Ca (OH) 2. The hemihydrate (mixture of α- and β- forms, prepared in the ordinary condition) was dehydrated by calcining in the temperature range of 300-320°C in air or in nitrogen to obtain anhydrous calcium sulfite (CaSO3). The anhydrate (mixture of α- and β- forms) set and hardened in the presence of water, converting into the hemihydrate. The present work was investigated manufacture conditions, effects of additive and stability on the hardened body of the calcium sulfite hemihydrate. The optimum conditions of calcining temperature were at 300°C in air or 320°C in nitrogen. Also the water carrying capacity to prepare the hardened body fitted at 90% in view of flowability in the slurry. The hardened body from the anhydrate calcined in air shows 65 kg/cm2 for compressive, 20 kg/cm2 for bending strength and 0.8-0.9 for bulk density. However, when 0.5-2.0 wt% oxalic acid as setting accelerator was added to the anhydrate, the setting was accelerated and the strength of the hardened body containing 2 wt% additive increased to 90 kg/cm2 for compressive and 30 kg/cm2 for bending. The hardened body of calcium sulfite hemihydrate was considered to be useful as an architectural material since it had a high thermal stability and a low water solubility in comparison with that of gypsum.View full abstractDownload PDF (2523K) -
Kiyoshi ITATANI, Akira KISHIOKA, Makio KINOSHITA1983 Volume 1983 Issue 182 Pages 12-18
Published: January 01, 1983
Released on J-STAGE: March 07, 2011
JOURNAL FREE ACCESSThe reaction between magnesium metaphosphate glass (MMP) and 85% H3PO4 was studied.. The products formed at 300°C in air were separated by centrifuging and subjected to X-ray powder diffractometry. The resulting Mg2P4O12 was examined by scanning electron micrography and the measurement of grain size distribution.
Two kinds of MMPs (MMP-1 and MMP-2) were prepared. The content of residual water in MMP-1 was 1.07 mol%, while that in MMP-2 was 9.53 mol%. The mixing ratios of MMP to 85% H3PO4 in weight (g) were 10 : 0.2, 10 : 1, 10 : 3, and 10 : 10.
In the case of powder mixtures of 10 : 0.2, 10 : 1, and 10 : 3, the only product formed was the cyclic compound Mg2P4O12. The Mg2P4O12 grains were observed to be spherulite and most of those obtained from the (10 : 3) sample were about 1 pm in diameter.
In the case of a slurry mixture of 10 : 10, Mg2P4O12 was formed by the condensation of MgH2 P2O7. The Mg2P4O12 grains were observed to be truncated bipyramids of 2 to 5 pm in diameter.
Mg2P4O12 grains from MMP-2 were larger than those from MMP-1. This is attributed to the. effect of residual water in the original MMP.
Mg2P4O12 obtained in this experiment had better crystallinity than those obtained in air. The grain size was controlled by changing the amount of H3PO4.View full abstractDownload PDF (1273K) -
Takafumi KANAZAWA, Takao UMEGAKI, Masatoshi CHIKAZAWA, Masayuki NAGAI1983 Volume 1983 Issue 182 Pages 19-26
Published: January 01, 1983
Released on J-STAGE: March 07, 2011
JOURNAL FREE ACCESSFive sludge samples, formed by lime treatment of exhaust solution or gas containing fluoride and phosphate ions, were gathered from the respective factories in 1977-1978, and were the subjects of various experimental tests.
The mineral compositions of the sludges were determined to be mixtures of “CaF2+ apatite+ others” with low crystallinities. No special characteristic surface properties were detected when the fine powder samples were compared to the synthetic calcium fluoride and fluorapatite.
Solid state reactions and thermal decompositions occurred on heating the sluge, which resulted in crack phenomena observed in the molded bodies heat-treated. Therefore, generally speaking, a high temperature treatment of this sludge for ceramic use may be inappropriate. We found, however, that a sintered body with a low relative density could be produced by a mild hot-press.
It was also recognized that there was a possibility of F-PO4 separation by wet-process treatments of the sludge using acid and solution solvents, for example, HCl and Al (NO3) 3 solutions, respectively. Entirely different results were obtained using the two treatments.View full abstractDownload PDF (880K) -
Kenichi HATTORI, Masanori IIZUKA1983 Volume 1983 Issue 182 Pages 27-34
Published: January 01, 1983
Released on J-STAGE: August 16, 2011
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Mitsuo HANADA1983 Volume 1983 Issue 182 Pages 34-41
Published: January 01, 1983
Released on J-STAGE: March 07, 2011
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X-Ray Powder Diffraction (1)[in Japanese]1983 Volume 1983 Issue 182 Pages 43-46
Published: January 01, 1983
Released on J-STAGE: March 07, 2011
JOURNAL FREE ACCESSDownload PDF (508K)
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