THE RECOVERY OF COARSE MINERALS BY AGGLOMERATION AND FLOTATION

The recovery of minerals, or in some cases the removal of contaminants, from ores and concentrates in the 150 micron to 3 mm size range has always presented a problem in extraction metallurgy. This paper gives three practical examples of how this problem has been successfully addressed. In the first application, coarse pyrite was removed from cassiterite jig concentrates through agglomeration on a specially-designed shaking table. Sulphide particles as large as 3 mm were floated off into the tailings stream. In the second application, copper sulphides in the 100 to 500 micron size range were successfully removed from a uranothorianite-baddeleyite heavy mineral concentrate using a Deister Flotaire cell. Recoveries in excess of 90 percent were obtained in a single stage of pilot-scale flotation, and this has led to the installation of two 0.76 m-diameter columns. Thirdly, the paper focusses on the pilot-scale recovery of a high grade, partially hydrolized phlogopite as a +98 percent concentrate using a similar type of cell. The design considerations for a pilot plant producing 100 t flake/month are described. In each of these three processes, the conditioning was carried out on a pulp which contained more than 50 percent solids by mass, since conventional conditioning did not prove to be effective.