Treatments of Magnetized. Bauxite by Reduction in Wet System

Abstract

The author has developed an improved method for the separation of red mud from an alkaline solution of bauxite (South Eastern Asia). The experimental results are summerized as follows. (1) The reduction of iron (III) oxide in bauxite by hydrogen with the aid of nickel catalyst was achieved in alkaline solution to produce magnetic iron (II) diiron (III) oxide. (2) The sedimentation rate of the magnetized mud was greater than that of non-magnetized one, except in the liquid medium of low density. However, when the liquid density was too low, the sedimentation rate decreased, and when the density became ca. 1.004, the mud almost stopped in falling. The reason of this decrease may be explained in terms of the peptization of the mud particles. The role of sodium ion was discussed in this regard. (3)A filtration apparatus of magnetized mud was devised. This was a filtration layer consisting'of iron powder placed in magnetic field. By this apparatus the separation of aluminate solution from the mud could be made completelyand rapidly.