Upgrading low-grade graphite tailing into high-grade graphite using agglomeration

Abstract

Low grade Graphite ore is mostly beneficiated by froth flotation. For the liberation of Graphite from the related gangue materials, flotation circuits depend heavily on wet grinding of the ore with grinding mills. This produces significant amounts of Graphite fines, which are eventually lost to the tailings and discarded as wastes without further Graphite recovery. Agglomeration of the Graphite fines has been proven to be a size enlargement technique by previous studies. The character of Graphite agglomeration for beneficiation of low-grade Graphite tailing samples containing 23.4% to 25.5% Fixed Carbon (FC) obtained from Ragedara Graphite mine, Sri Lanka was assessed by varying the bridging liquid to tailing ratio and increasing the sample size. Comparative surface changes of upgraded Graphite were observed using Hitachi SU6600 Analytical VP FE-SEM. With respect to the froth flotation process, this novel method will need low water requirement while reducing the time for the separation of Graphite. The beneficiation study was able to obtain a concentrate with 88% fixed carbon at 69.6% recovery for 25 kg sample with no major surface structural changes compared with Natural Vein Graphite, indicating that it could be applied on commercial scale with periodic iterations for upgrading over 99% fixed carbon.