抄録
(1) The length of time of the aqua regia digestion are giving showing that have an effect on the results for the insoluble material in phosphate rock. (2) The silica was determined in a number of samples of phosphate rocks by the Berzelius and ordinary alkali fusion methods. The results show that, owing to the presence of fluorine in phosphate rock the percentage of silica obtained by method of ordinary rock analysis, are 0.02〜2.22 percent lower than the percentages obtained by the Berzelius method. (3) The Berzelius procedure is shown to be applicable to the determination of silica in phosphate rock. (4) The silica contents was determined on the phosphate rocks from continental or Island origins by the Berzelius method. The average contents from Florida was 10.43% the Idaho, 6.56% : the Algeria 1.60% : the Egypt, 5.29% : the Morocco, 1.60 : the Angaur, 0.46% : the Christmas, 0.27% : the Makatea, 0.33% : the Ocean, 0.65% : the Raokai, 5.81% : the Paracel, 0.28%. (5) The amounts of hydrochloric acid, sodium carbonate, sulfuric acid soluble silica, and free silica as quartz was determined on the few samples. Chemical Research Institute, Taki Fertilizer manufacturing o., Befu
