GB537401A - Improvements in or relating to a flotation process and to a flotation cell, for separating particles from pulp material containing the same, and capable of separating relatively coarse particles - Google Patents

Abstract

537,401. Concentrating coal &c. STEVENS, A. H. (Philade1phia & Reading Coal & Iron Co.). June 9, 1939, No. 16953. [Class 82 (ii)] A flotation process, for example, for coal, comprises introducing into a pulp in the lower part of a cell a controlled supply of air or gas so limited as to produce minute bubbles which remain minute and are present in insufficient quantity to cause coalesoence into larger bubbles, effecting classification in a quiescent zone of the cell. and removing the resulting froth which floats adjacent to and beneath the surface of the liquid. In the apparatus shown, the pulp, which may be conditioned by the addition of collecting and frothing agents such as kerosene and cyanamide, is fed through an inlet 3 to the upper face of an impeller 4 beneath a column 6 to which a current of air or gas is admitted through an adustable port 6b. The impeller discharges the mixture into a zone A and thence through vertical baffles 10 and grids 11, 11a to a separating zone B. Middlings pass into pockets 12 from which they may be returned to the inlet 3, or to another cell, while the concentrate which forms beneath the surface of the liquid is removed by conveyers 13, water sprays 17 being provided to clean the concentrate as it is being removed. Tailings pass out through an adjustable opening not shown. A series of such cells may be used, the tailings from one being treated in the next.