石膏と石灰
Online ISSN : 2185-4351
ISSN-L : 0559-331X
1966 巻, 85 号
選択された号の論文の5件中1~5を表示しています
  • (第7報) 鉱酸によるリン酸セッコウの脱水および水和
    山田 保, 水谷 千尋, 永井 彰一郎
    1966 年 1966 巻 85 号 p. 198-202
    発行日: 1966/11/01
    公開日: 2011/03/07
    ジャーナル フリー
    The constitutional diagram of gypsum in the H3PO4 acid (1) or mixed acid of H3PO4 and H25O4 (2) has been reported already. But there are many questions about phosphoric acid gypsum which have not been solved.
    In the present paper, we have examined the dehydration and hydration of gypsums produced by actual phosphoric acid process. We have examined 4 phosphoric acid gypsums. Their analytical comosition (3) is as Table 1, and their crystal figure is as Fig 1. And, for reference, a extra pure gypsum and a clay gypsum were also examined.
    These gypsums in 10 to 40% H2504 were dehydrated by heating as shown in Fig. 2. The higher acid than 50% H2SO4 makes the all gypsum to anhydride but hemihydrate state. When the acid is more dilute than 40%, A and C gypsum has hemihydrate zone, but B and D has not. We assumed this difference is caused by anhydrite contained in B and C, for the solubility of anhydrite is so lower than hemihydrate that hemihydrate precipitates to the anhydrate. The experimental comfirmations of this assumption shall be reported in another paper.
    Both the reagent gypsum and clay gypsum dehydrate at apploximately same temperature calculated by Nordengren's (1) and Murakami's (4) equation.
    In HCl and HNO3 all gypsums dehydrate in same way as shown in Fig. 3. We suppose this cause is that the anhydrite of the gypsum is all solved out by these acid until it can not precipitate.
    As per Fig. 4 the hydration velocity in H2SO4 is higher than in HCl. The gypsum of uniform and grane crystal as A dehydrate linearly by heating time, but another gypsum of thin and irregular form crystal, dehydrate more easily and quickly. (5, 6) These character of dehydration is the causes of difference of dehydration of Fig. 2 and 3. By hydration of hemihydrate of A in the acid to which the crystal modifier of Fe3+ or Al3+ ion, (7, 8) is added, the gypsum crystalize out to the uniform and 2 to 3 times as large as crystals.
  • 笠井 順一, 市場 正夫, 中原 万次郎
    1966 年 1966 巻 85 号 p. 203
    発行日: 1966/11/01
    公開日: 2011/03/07
    ジャーナル フリー
  • 高橋 博
    1966 年 1966 巻 85 号 p. 204-218
    発行日: 1966/11/01
    公開日: 2011/03/07
    ジャーナル フリー
    The writer studies a geophysical prospecting on the structure of limestone deposit. By electrical prospecting the thickness of “soil” which lies the limestone determined on the range of practical accuracy. And in this paper problemes of prospecting of limestone deposit are also discussed.
  • 青木 繁樹, 藤田 輝彦, 中原 万次郎
    1966 年 1966 巻 85 号 p. 219-224
    発行日: 1966/11/01
    公開日: 2011/03/07
    ジャーナル フリー
  • 日本石膏ボード工業組合
    1966 年 1966 巻 85 号 p. 228-236
    発行日: 1966/11/01
    公開日: 2011/03/07
    ジャーナル フリー
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