Abstract: A flotator for use in benefication, coal dressing, wet refining and so forth, incorporating a surface flotation technic. The flotator has a funnel-shaped liquid cell having a bottom of an area smaller than that of the top opening. A bubbling device is constituted by an upper sleeve partly immersed in the liquid contained by the cell, a lower sleeve disposed coaxially with the upper sleeve and fully immersed in the liquid. The upper end of the lower sleeve is spaced by a predetermined distance from the lower end of the upper sleeve to form therebetween a spaced region located at a small depth from the liquid surface. The bubbling device further has a rotary blade unit constituted by upper and lower blades separated by a flat partition plate.

Abstract: A method of drying brown coal in which the brown coal is pelletized before the drying into pellets of 2 to 5 mm dia. by a wet pelletizing process making use of the water contained by the coal itself as the binder. The brown coal in the form of dried pellets has a larger bulk density than the brown coal in the form of fine powders which are obtained when the brown coal after the exploitation is directly dried, and, therefore, contributes to the reduction of the transportation cost. In addition, the dried brown coal in the form of pellets can be handled and transported in quite an easy manner, as compared with the case of powdered brown coal. Further, thanks to the improved ventilation afforded by the gaps between the pellets, the possibility or chance of undesirable spontaneous combustion is greatly reduced.