Abstract: An apparatus to burn carbon bodies has at least two independently controllable electric resistance heating circuits, at least two temperature sensors and a comparator. Two or more regions of a selected carbon body can be independently heated by the two circuits. The actual temperature of each of those two or more regions can be monitored by corresponding temperature sensors connected to the comparator. The comparator controls each electric resistance heating circuit independently so as to minimize any difference between a preselected temperature and the actual temperature of each region.

Abstract: An agitation flotation cell for the preparation of minerals and coals having at its lower end a structure including a vertical shaft with a disk at the lower end of the shaft being circular in plan view with said disk having a first lateral section tapering outwardly and downwardly from a central diametral line passing through the shaft and a disk having a second lateral section tapering outwardly and downwardly from the central diametral line with the two sections meeting at a peak to form a roof-shaped surface with first and second radially extending vanes projecting above the first and second sections extending at right angles to the peak and third and fourth radial vanes extending downwardly from the peak on the bottom side of the vanes and being parallel to the peak.