n
n
Dramatically reduce coal dewatering costs.
n
n
Drastically reduce the high cost of large filter presses.
n
n
Eliminate the need for a large number of tailings ponds.
Background
At one coal washing plant in India, fine tailings (typically
- 0.5 mm) from the flotation circuit were thickened using a
thickener and then pumped to a tailings pond. After
settlement, clear water was pumped back to the washery and
solids were allowed to dry. The solids were then removed
and sold to many buyers. This process required a large land
area for the tailings pond. In addition, considerable amounts
of water was being lost due to evaporation and seepage.
Solution
Derrick HI-G dryers were recommended to assist in
dewatering the thickened solids. The units are now operating
in combination with filter presses to provide online
dewatering of the solids. Clear water is recirculated to the
washery and dewatered solids are taken to a storage yard for
disposal/sale. In the plant, which was designed with the
assistance of Derrick Corp, tailings from washery 2 and
washery 3 are pumped to this plant where hydrocyclones are
used for separating solids at 0.15 mm and thickening to 50%
solids. Thickened solids are dewatered using six HI-G dryers
and the - 0.15 mm fraction is sent for dewatering in filter
presses. Nearly 75% of the total 240 tph solids are recovered
in Derrick screens and 25% are dewatered in the filter
presses. Clear water containing less than 100 ppm solids is
pumped back to the respective washeries, while solids are
stored for disposal.
Conclusion
This environmentally-friendly plant has helped in eliminate
a large number of tailings ponds. Many coal clients are now
planning to duplicate this technology in their coal washing
plants.
New flow sheet incorporating Derrick HI-G
®
dryers.
HI-G dryer dewatering thickened solids.
Cover story: Derrick HI-G
®
dryers
cleaning for tough applications,
concluded the company.
Telescoping radial
stacker automation
Superior Industries has released
version 12.0 of its telescoping radial
stacker automation program, giving
the software a “major makeover”,
according to the company.
“The new, user-friendly screen
design is equipped with bolder
graphics and modern onscreen buttons
to help users navigate the software
more easily,” the company said in a
press release. “In addition, navigation
was tweaked to help improve the user
experience. Also new, the automation
software is now equipped with
onscreen access to the TeleStacker
conveyor owner’s manual and a
running meter that reports the unit’s
motor hours.”
According to the company,
TeleStacker conveyors dating all the
way back to the original units, which
were manufactured in 1997, can be
upgraded.
High-speed conveyor
backstop
Engineers from a Pennsylvania coal
mine have chosen Stieber Clutch’s
RDBK high-speed backstop to meet
the requirements of a new inclined
conveyor. According to the clutch
manufacturer, the RDBK is a
centrifugally operated, lift-off sprag,
high-speed backstop. It is equipped
with integral torque limiter that limits
the backstop’s transmissible torque to
a value that is factory set, in agreement
with user specification – a feature that
is often specified on multi-drive
systems, such as large inclined
conveyors, where two or more
backstops share the reverse load.
The backstop is designed to be fully
bearing-supported. It rotates
backwards under overload so it can
perform several reverse rotations as
86
|
World Coal
|
June 2015
