Abstract:
Froth floatation is the only beneficiation technique currently need for low-grade
Graphite. Liberation of Graphite from Graphite bearing rocks for the froth flotation
is more prominent using wet grinding techniques with grinding mills. This
generates a high amount of Graphite fines of size less than 100 microns which
ultimately mixed w i t h tailing and discarded as waste without further recovery of
Graphite. This occurs as the froth flotation process is optimum for recovering a
range of particle sizes between (100 to 200) microns. Agglomeration of Graphite
fines has been proven to be a possible by size enlargement technique proven by
previous studies.
I n the initial stages of the study, the character of the low-grade Graphite tailing
samples obtained from the column flotation plant of Ragedara Graphite mine was
characterised by carrying out analysis on particle size distribution and the amount
of fixed carbon according with the American Standards for Testing Materials
(ASTM). In the latter stages of this comprehensive study, the amenability of the
agglomeration of Graphite for the beneficiation of low grade Graphite tailing
samples containing 23.4% to 25.5% of fixed Carbon from Ragedara Graphite mines
was assessed by varying bridging liquid to tailing ratio for optimum purity and
recovery of Graphite. The study continued with increasing the sample size from
1 kg to 25 kg for variations in purity and recovery of upgraded Graphite for a fixed
bridging liquid to tailing ratio. The surface structural changes of upgraded Graphite
was observed with comparison to Natural Vein Graphite (NVG) using Scanning
Electron Microscope (SEM).
The beneficiation study has been able to obtain a concentrate with 88% fixed Carbon
at a recovery of 69.6% for 25 kg sample suggesting its amenability to be
implemented i n commercial scale w i t h periodic iterations for upgrading over 99+%
fixed Carbon. The results from the SEM study i n similar topographies using three
different magnifications (xl20, xlOOO and xl2000) have suggested no significant
changes between the untreated NVG and the agglomerated NVG.
With respect to the froth flotation process, this novel processing method has a low
water requirement and ability to process tailing w i t h any purity, while cutting off
the time for the separation of Graphite and also reduce the loss of the Graphite fines
to the tailing, while improving sustainability of the process.
Citation:
Mushmika, P.A.S., Lakshitha, E.D.P., Kusumsiri, G.A.R.L., Dissanayake, D.M.D.O.K. & Rohitha, L.P.S. (2019). Upgrading low-grade graphite tailing into high-grade graphite in pilot scale using agglomeration [Abstract]. In D.M.D.O.K. Dissanayake & G.V.I. Samaradivakara (Eds.), Proceedings of International Symposium on Earth Resources Management & Environment 2019 (p. 121). Department of Earth Resources Engineering, University of Moratuwa.