18 BULKDISTRIBUTOR
Industrial Packaging
January/February 2016
Freeing the zircon bottleneck
A Flexicon heavy-duty bulk bag filling station handles abrasive zircon and rutile
T
ronox Western Australia operates the
world’s largest fully integrated titanium
ore and titanium dioxide (TiO2) project,
covering the spectrum from mining of mineral
sands through extraction and upgrading to
obtain TiO2 pigment.
The project is also a major producer of the
mineral zircon (zirconium silicate), which is also
obtained from the mineral sands.
The chief products at Tronox’s Western Australian
operations are rutile (TiO2) and zircon (ZrSiO4),
which ultimately are loaded into bulk bags (FIBCs)
at Tronox’s Henderson shipping facility and
transported in shipping containers to nearby
Fremantle, Western Australia’s largest port for
export and domestic use.
The loading of bulk bags over the years had
become a bottleneck, but has been remedied by a
special bulk bag filling station from Flexicon
Corporation Australia.
Tronox’s Western Australian operations start with
the mining of mineral sands, which are gravityseparated at the mine to obtain a wet concentrate
that is rich in the desired minerals: rutile (highgrade Ti mineral), ilmenite (FeTiO3 ,lower-grade Ti
mineral), and zircon. The minerals are separated
and recovered by magnetic and electrostatic
processes at the company’s Chandala dry
separation process plant in Muchea. Ilmenite is
further refined in a reduction kiln to remove iron
and ultimately produce synthetic rutile.
The granular zircon and rutile are brought to the
company’s shipping facility in Henderson in tipper
trucks, which empty their loads onto the concrete
floors of large storage sheds. From there, the
product is loaded into bulk bags.
The bagging operation was largely a manual
process in which a forklift truck held the bag while
a second forklift truck held a V-shaped funnel (or
hopper) over the bag and a front end loader
dropped the ore through the funnel into the bag.
When the bag was nearly full it was weighed and
the rest of the material was added by hand.
Tronox dramatically improved its bulk bag filling
with a heavy-duty skid-mounted mobile bulk bag
filling station that integrates a 2.5 cbm capacity
hopper, a 4.5m long steel tube screw conveyor,
and a Twin-Centrepost bulk bag filler.
Nicknamed ‘Rhonda’ at the Henderson facility,
the bulk bag filling station stands 3.3m at its
highest point and is 3.6m long. It was engineered
and supplied by Flexicon (Australia) Pty Limited
(Wacol, Queensland), a subsidiary of Flexicon
Corp. (Bethlehem, Pennsylvania, USA). The unit
doubles output per operator over the former
method, while improving health and safety since
filling is enclosed and essentially dust-free,
according to the company.
Formerly, three employees filled about 80 bags in
a 10-hour day. Currently, two employees fill about
90 bags in an 8-hour day.
Heavyweight operation
The Flexicon Twin-Centrepost design with two
on-centre posts maximises strength, which is
essential since the unit must fill material of
differing weights — 1,000kg, 1,750kg and
2,000kg. The basic design consists of two steel
posts, which support a fill head and pneumaticallyretractable hooks on which the bag hangs.
Enclosing the bulk bag filler and supporting the
Skid-mounted mobile bulk bag filling station at the Tronox Henderson facility consists of a 2.5cbm capacity hopper, a 4.5m long tubular screw
conveyor, a Twin-Centrepost bulk bag filler, and PLC control
4.5m long tubular conveyor is the station’s heavyduty outer frame.
The bag filling station moves between the zirconand rutile-filling operations, which are located
approximately 800m apart. Due to its relatively
small footprint, the skid-mounted system can be
moved using a three ton forklift.
Nevertheless, the capacious hopper can hold
6.4–7.3 tonnes of zircon or 4.5–5.4 tonnes of
rutile, in granular form. During filling, the front
end loader empties material into the hopper while
the conveyor draws the material from the inlet at
the bottom of the hopper and transports it 4.5m
at an incline of 40deg before it gravity feeds
through the conveyor outlet, transition adapter
and telescoping steel downspout into the bulk
bag.