Beneficiation of limestone plant rejects for value addition

Attempts have been made to recover the additional calcium values from the limestone plant rejects by flotation as a beneficiation technique. The characterization study indicates, quartz and calcite are the major minerals present in this sample, while concentrate is highly upgraded with calcite content, by rejecting mostly quartz and clays in the tailing. Systematic studies have been conducted at different operating conditions using conventional cell and column flotation. A concentrate of 42.50% CaO content at an yield of 15.65% is produced by two stage conventional cell flotation from the limestone rejects with 12.09% CaO. Further enhancement in grade and yield of the concentrate could be achieved using single stage column flotation. The process flowsheet developed can be adopted to treat these rejects for production of cement grade concentrate.