An 8-acetoxyquinoline solution was added to the solution of pH 9 containing cadmium and lead ions to precipitate the 8-hydroxyquinolate from homogeneous solution. The crystal habit of the precipitates was studied from the viewpoint of crystal chemistry. Cadmium 8-hydroxyquinolate appeared initially in the needle form accompanied with a slight amount of lead. The precipitation of most of cadmium was followed by the precipitation of lead 8-hydroxyquinolate crystals in the long needle form. The needle crystals of cadmium 8-hydroxyquinolate belonging to the tetragonal system. transform easily to the hexagonal plate crystals belonging to the monoclinic system. But the transformation was restrained by the presence of stable needle crystals of lead 8-hydroxyquinolate. When cadmium and 8-acetoxyquinoline solutions were added to the suspended solution of the needle crystals of lead 8-hydroxyquinolate at pH 9, lead was replaced so rapidly with cadmium that cadmium 8-hydroxyquinolate formed as the needle crystals, and then the appearance of the long needle crystals of lead 8-hydroxyquinolate was followed. Cadmium 8-hydroxyquinolate crystals formed were of needle shape, differing from the hexagonal plate in the stable form, but it was found that their crystal structure belonged to the monoclinic system. The shape of cadmium 8-hydroquinolate crystals was affected by the presence of the needle crystals of lead 8-hydroxyquinolate and they kept the needle shape.

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水中又は海水中などに存在する極低濃度のバリウムを分離濃縮して定量するための基礎研究として,スルファミン酸の加水分解による均一溶液からの沈殿法(PFHS法)を用いて硫酸鉛に対するバリウムの共沈殿について検討した.鉛と少量のバリウムの混合溶液にスルファミン酸を加えて80℃で反応させたとき生成する沈殿を分析した.バリウムは硫酸鉛に対して濃縮系となって共沈殿し,かつ対数分配の法則に従い,対数分配係数は2.33となった.又,海水及び河川水中のバリウムを,硫酸鉛共沈殿法によって濃縮,原子吸光法によって測定し,海水11中約0.15mg,河川水11中約0.01mgのバリウムが溶存することが分かった.

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In order to understand the formative processes and textural change of anglesite from galena under natural sulfuric acid condition, chemical reaction of galena with sulfuric acid was experimentally examined. In the experiment, galena was sealed in the polypropylene bottle with sulfuric acid solution, and left for fixed duration in time. Three series of experiments, i.e., long term, rate analysis and solid textural analysis experiments, were carried out with changing temperature (30 to 170 °C), concentration of sulfuric acid (0.01 to 1 mol/l), duration (1 to 56 days) and state of galena (powder, grains or plastic crystals). The run products were filtered by 0.20 μm membrane filters, and the filtrated solution and residual solid were analyzed.
In the residual solid for all runs, the one and only identified reaction product is anglesite. In the long term experiment using powdered galena for 56 days, the amount of anglesite production increases with the increases of sulfuric acid concentration and temperature, which is well correlated with the equilibrium calculation results with considering oxygen contents in the bottle. The rate analysis experiment using powdered galena indicates that the amount of anglesite production increases with reaction time. Dissolution rate of galena for 1 day increases with the decrease of sulfuric acid concentration and the increase of temperature, in the range of 8.29×10^-9 mol・m^-2・s-¹ for the conditions of initial sulfuric acid 1 mol/l-110°C and 1.83×10^-8 mol・m^-2・s^-1 for 0.1mol/l-170°C. In the solid textural analysis experiment using grains or plastic crystals of galena, two types of anglesite occurrence are found, i.e., coarse euhedral crystals growing outside on galena surface and aggregates of fine grains which replace the initial galena crystal from surface. This differences would be explained by the degree of saturation for lead and sulfate ions under the microenvironment at the site of their formation. The random orientations of coarse euhedral crystals of anglesite on galena may be due to nonepitaxial growth. The increase of size of coarse euhedral crystals with time can well be explained by the Ostwald ripening.

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共沈殿現象の一端を解明しようとして,結晶系,溶解度が異なるが組成の類似したクロム酸鉛-バリウム系について検討した.バリウムと鉛の等モル量混合溶液にpH4.5で硝酸クロムと臭素酸カリウムを加えて一定温度で反応させ,いわゆる均一溶液からの沈殿法でクロム酸塩を沈殿させた.溶解度の小さいクロム酸鉛が優先的に沈殿し,バリウムが少量共沈殿した.長時間反応すると,単斜晶系のクロム酸鉛と斜方晶系のクロム酸バリウムが別個に生成した.

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