Recovery of economic minerals from the Carbonatite-Sevattur (Tamil Nadu)

Abstract

Carbonatites from Sevattur contain pyrochlore and apatite with calcite as the main gangue. The feed sample assayed 0.5% (NbTa)2O5 and 10.0% P2O5. The pyrochlore (uraniferous type) is in metamic state and is disseminated. Mineralogy was studied. Based on bench scale beneficiation tests conducted on batches of 19 to 100 kg, a flowsheet was proposed for the recovery of Nb-Ta concentrates (pyrochlore) and acid grade phosphate (apatite) from this carbonatite. The low concentration of pyrochlore [0.5% (NbTa)2O5)] in feed necessitated upgradation in stages to at least 60 times the feed value. Ore was ground to -48 mesh (wt% 98) and wet tablet. Table tails were scavenged in flotation circuit depressing pyrochlore with sodium silicate. The floats (calcite-apatite) were set apart for apatite recovery by calcination method. The cell products together with the table concentrates were subjected to magnetic separation. The non-magnetics were further recleaned and refined employing wet tabling followed by reverse flotation of pyrochlore (after sulphuric acid treatment). The recoveries obtained so far are (NaTa)2O5 (pyrochlore recovery 20% at 30% grade, P2O5 (apatite) recovery 50% at 35.2% grade. (Ch. Rambabu, J.B. Narasimhan, G.V.U. Rao and K.K. Majumdar, Ore Dressing Division, BARC, Bombay)