著者
安達 正雄 谷本 明
出版者
無機マテリアル学会
雑誌
石膏と石灰 (ISSN:21854351)
巻号頁・発行日
vol.1975, no.135, pp.63-72, 1975-03-01 (Released:2011-03-07)
参考文献数
75

To analize mechanism of calcium scale deposit on heated wall in evaporator, accurate solubility data of calcium sulfate in pure water are required, but satisfactory data are not available from databooks. Therefore, an attempt to determine the equations which represent accurately the solubility of calcium sulfate is performed.All the solubility data which are taken from available original literatures are classified in five groups corresponding to modifications of calcium sulfate, i. e. dihydrate, α-and β-hemihydrate, soluble anhydrite and insoluble anhydrite. The equations for each group are determined by so-called double-minimum-square method using digital computor FACOM 230-35 of Kanazawa University.It is found that all the data for soluble anhydrite are obviously classified in two groups. Because of this fact and the other verification, two types of α and β exist in soluble anhydrite. At last, the equations of solubility for six modifications of calcium sulfate are presented. Deviation of the data from the equations are less than ±10% for temperature ranges from 0 to 170 or 200°C, but for dihydrate ±-1%, 0 to 110°C.It seems that the given each equation of solubility for modifications of calcium sulfate is the most accu-rate, comparing with the other's solubility equations.
著者
荒井 康夫 安江 任
出版者
無機マテリアル学会
雑誌
石膏と石灰 (ISSN:21854351)
巻号頁・発行日
vol.1983, no.187, pp.357-366, 1983-11-01 (Released:2011-03-07)
参考文献数
17

1 0 0 0 OA 人工宝石

著者
兒嶋 弘直
出版者
無機マテリアル学会
雑誌
石膏と石灰 (ISSN:21854351)
巻号頁・発行日
vol.1988, no.214, pp.177-182, 1988-05-01 (Released:2011-03-07)
著者
貫井 徳蔵
出版者
無機マテリアル学会
雑誌
石膏と石灰 (ISSN:21854351)
巻号頁・発行日
vol.1990, no.228, pp.303-309, 1990-09-01 (Released:2011-08-16)
参考文献数
27
著者
松田 伸一 池上 隆康 小浜 弘之
出版者
無機マテリアル学会
雑誌
石膏と石灰 (ISSN:21854351)
巻号頁・発行日
vol.1986, no.202, pp.142-151, 1986-05-01 (Released:2011-03-07)
参考文献数
20

Magnesium basic carbonate was synthesized by using so called “the sodium carbonate method”. The process composed of following steps such as precipitation and dissolution of the amorphous basic carbonate, crystallization and dissolution of the carbonate (nesquehonite), and the formation of the basic carbonate.The results obtained are summarized as follows : 1) The crystallinity of nesquehonite depends on the concentration ratio of [CO32-] / [OH-] 2.2) The formation rate of the basic carbonate depends on the dissolution rate of nesquehonite and the concentration ratio of [OH-] / [HCO3-].3) The composition of basic carbonate depends on aging conditions, that is 4MgCO3·Mg (OH) 2·8H2O is stable at high concentration of [OH-] and low temperature, 4MgCO3·Mg (OH) 2·5H2O (dypingite) is stable at low concentration of [OH-] and high tempbrature.4) Ultimate composition of basic carbonate depends on the drying temperature. 4MgCO3·Mg (OH) 2· 5H2O (giorgiosite) is stable at room temperature, on tne other hand, 4MgCO3·Mg (OH) 2·4H2O (hydromagnesite) is stable at about 110 °C.Above results indicate that the concentration of initial solution, the aging temperature, and the pH of mother's solution play the important role on the synthesis of magnesium basic carbonate.
著者
宮沢 清
出版者
無機マテリアル学会
雑誌
石膏と石灰 (ISSN:21854351)
巻号頁・発行日
vol.1969, no.103, pp.332-337, 1969-11-01 (Released:2011-03-07)
参考文献数
10
著者
湊 秀雄
出版者
無機マテリアル学会
雑誌
石膏と石灰 (ISSN:21854351)
巻号頁・発行日
vol.1977, no.147, pp.80-88, 1977-03-01 (Released:2011-03-07)
参考文献数
4
被引用文献数
2
著者
小俣 一夫
出版者
無機マテリアル学会
雑誌
石膏と石灰 (ISSN:21854351)
巻号頁・発行日
vol.1989, no.222, pp.262-268, 1989-09-01 (Released:2011-03-07)
参考文献数
18
著者
近藤 連一 大門 正機 大沢 栄也
出版者
無機マテリアル学会
雑誌
石膏と石灰 (ISSN:21854351)
巻号頁・発行日
vol.1971, no.112, pp.92-96, 1971-05-01 (Released:2011-03-07)
参考文献数
12

The equations showing the relationship between the rate of water absorption and the pore size of porous materials were studied in connection with the water absorption phenomena in consideration of the various capillary models and also new equations were tentatively derived.The water absorption experiments were done by using hydrated α and β-CaSO4·1/2 H2O for examples and the previonsly mentioned equations were applied to the results and some discussions were made. The electrical resistance which changes with absorption of the ionic solution into the specimen was measured for the calculation of the through pore size distribution.The results showed that in the case of β-CaSO4·1/2 H2O, the varying radius capillary model in which each capillary has various radius was in good accordance with the structure estimated by the mercury penetration method and the scanning electron microscope observation. While, the pore size distribution of α-CaSO4·1/2 H2O showed good accordance with the meandering capillary model rather than that with the varying radius model. The straight capillary model might be in general inadequate. These facts seem to indicate that the tortuosity is related with either the variation of radius in each capillary or the meandering of each capillary, varying with the sort of specimen.It was found that the method to measure the rate of water absorption is valuable to study the pore structure of the materials.
著者
小田部 廣男
出版者
無機マテリアル学会
雑誌
石膏と石灰 (ISSN:21854351)
巻号頁・発行日
vol.1987, no.210, pp.307-316, 1987-09-01 (Released:2011-03-07)
参考文献数
9