Abstract: An apparatus for drying and classification of a material, the apparatus including a drier (1) having a rotatable drying drum (2) that is substantially horizontal or slightly inclined relative to the horizontal direction for drying a moist material being fed through a first end (3) of the drier, and a screen device (4) provided at a second end (5) of the drier to receive dried material passed through the drying drum for classification of the material. The screen device (4) is a multilayer screen including nested screen drums (6, 7, 8, 17) attached to the drying drum (2) to rotate with the drying drum about a common rotating axis (x-x).

Abstract: A steam drier including a rotatable elongated drum (1) and a set of heating elements (2) provided in the interior space within the drum and supported on the drum in order to rotate along with it. Each heating element (2) includes a pair of straight first longitudinal pipes (3, 4) supported in parallel to each other at a distance (A) from each other. The first longitudinal pipes extend in the longitudinal direction of the drum. A pair of end pipes (5, 6) extends substantially transversely relative to the first longitudinal pipes in the vicinity of the ends of the first longitudinal pipes. The end pipes connect the first longitudinal pipes rigidly to each other. The first longitudinal pipes are provided in flow connection to each other through the end pipes in order to allow the flow of steam within the heating element. The heating element (2) includes a set of straight second longitudinal pipes (7) provided in parallel to the first longitudinal pipes (3, 4).

Abstract: An apparatus and method for feeding powderized raw material, such as aluminum oxide, into an aluminum producing electrolysis reaction, in which the electrolysis is produced by an anode and cathode apparatus and a powderized raw material is conveyed from a silo or equivalent to a feeding apparatus and then into an electrolyte melt. The feeding apparatus has a controlling box for controlling the raw material feeding and a feeding pipe connected thereto. The feeding apparatus has a feeding device arranged to operate within the box and connected through a piston shaft to a vibrator. The vibrator produces a substantially vertical vibration of the feeding device. An open lower end of the controlling box is positioned in the vicinity of the surface of the electrolyte melt so that the controlling box operates within the electrolyte crust.

Abstract: A method and device for feeding a raw material, such as aluminum oxide, into an aluminum electrolysis using a reciprocatingly vibrating feeding means in which a raw material is carried into a controlling box positioned in proximity to the surface of electrolyte melt. Mechanical vibrations are directed at a feeding device positioned inside the controlling box. The vertical amplitude of the vibrations is selected in the range of about 0.5 cm to about 1.5 cm. The oscillation frequency of the vibrations is selected in the range of about 11 Hz to about 40 Hz. Raw material is continuously fed by the feeding device into the electrolysis through an opening produced in the crust of the electrolyte melt around the controlling box.