1965 年 15 巻 4 号 p. 203-208
Sulfur dioxide gas was passed through an aqueous suspension containing red mud, a by-product of alumina manufacture by the Bayer process, and the following results have been obtained:
(1) Dissolutions of Na, Si and Al cease practically in about 10min.
(2) Sodium aluminosilicate in the red mud is thoroughly decomposed.
(3) The rates of dissolution of Na, Si and Al are respectively estimated to be 100, 80 and 60%, however, those of Fe and Ti are very little.
(4) There is little effect of temperature on the dissolution of the components of the red mud.
(5) With increase in a ratio of red mud to water, the quantities of the components of the red mud dissolved are increased, however, the rates of dissolution of Na, Si and Al remain unchanged and those of the other components are decreased.
(6) The higher the concentration of the sulfur dioxide gas, the larger the quantities of the components of the red mud dissolved, and the decomposition of the insoluble sodium aluminosilicate can be almost taken place with 10% sulfur dioxide gas.
(7) From the experimental results mentioned above, the optimum conditions to recover Na, Al and Fe from the red mud by the present process have been determined.