GB1131649A - Method of and apparatus for separating mineral particles by a flotogravitation process - Google Patents

Abstract

1,131,649. Separating minerals by froth flotation. GOSGORKHIMPROEKT. 7 Sept., 1966, No. 39985/66. Heading B2H. In a process for separating mineral particles by froth flotation a pulp of the particles is caused to froth by aeration, the frothed pulp is fed on to the surface of an aerated fluid so that it spreads in a layer over the whole surface of the fluid, an ascending flow is caused in the aerated fluid in the region where the frothed pulp is fed on to it, and a flow is caused, at the surface of the aerated fluid at which separation occurs, in a direction from the pulp feed-in region to a location at which the required separated fraction of the mineral particles is discharged, the intensity of aeration of the fluid being decreased in the direction of flow at the surface of the fluid. In the apparatus shown in Fig. 2, the fluid is contained in a tank I and is aerated by air blown through two rows of perforated pipes 2 connected to collectors 3, 4, the collector 3 having three sections each of which is connected to a source of compressed air in such a manner that more air is fed into the tank at the pulp feed-in region than at the froth product discharge region. Reagentconditioned pulp is fed through a pipe 9 and spreads into a thin layer on to inclined decks 8 arranged in cascade. A spreader 11 distributes the pulp evenly into two launders 7 in which air and liquid are added to the pulp by means of perforated pipes 12 and nozzles 13 respectively The frothed pulp spills over the upper curved portions of the walls 14 of the launders on to the surface of the aerated liquid. The non-uniform delivery of air in the tank I gives rise to a vertical upward flow of liquid and air bubbles in the pulp feed-in zone where the bubbles concentrate, this upward flow being changed to a horizontal flow by the upper curved portion of the launder walls 14 thus carrying the froth and the desired separated particles contained therein towards an over flow lip at the tank periphery. The unwanted particles sink towards the bottom of the tank and are removed through an automatically operated valve 5. In a modification, Fig. 3, the fluid is aerated by means of air which is fed with water as a mixture through ejectors 15 which direct the mixture against the launder walls 14 so as to create the concentration of air bubble in the pulp feed-in zone and the horizontal flow in the surface of the fluid. In a further modification, Fig. 4 (not shown), aeration of the fluid is by air blown through a row of perforated pipes and through nozzles arranged in the sides of the tank above the level of .perforated pipes. In a still further modification, the apparatus may be one-sided and have only one launder 7 in which case the spreader 11 is dispensed with. Instead of a valve 5, a screw or a conveyor may be provided.