PASTE & TAILINGS 2020
water to the plant, CDE’s AquaCycle is a highly
efficient water management solution that
minimises costly water consumption by ensuring
up to 90% of process water is recycled for
immediate recirculation.”
After feed material has been washed and
classified, waste is sent to the AquaCycle
thickener tank. Here, a small amount of
polyelectrolyte flocculant is added to the water
via an automatic dosing station. This forces fine
particles to settle on the bottom of the thickener
tank. The clean water on the top overflows the
weir and is stored in the AquaStore tank before
being re-circulated around the plant. The result is
a highly efficient water recycling system that
requires only a 10% supply of top-up water,
according to CDE.
Waste sludge is discharged into a buffer tank
where a motorised rake in constant rotation
ensures the material does not settle and solidify,
according to the company. If further dewatering
is required, a filter press or decanter is added to
the wet processing solution to eliminate the
need for settling ponds.
Intelligent design
Though water recycling may seem simple in theory,
it is, in practice, much more complex, CDE says.
“Water thickeners are not born equal and their
efficiency is the result of years of dedicated
research, development, and refinement,” it
added. “Every aspect of its design is carefully
considered so that the system is responsive to
the site-specific needs of its owner.”
Kevin Vallelly, Director of Engineering at CDE,
says the company sweats “the small stuff”.
“CDE has been co-creating with customers for
over 25 years to deliver collaborative,
imaginative and unique processing systems, and
this process has been informing and refining our
water recycling technologies,” he said.
All CDE equipment is designed to allow plugand-play
operation, with equipment pre-wired
and pre-tested before despatch, designed for
rapid assembly and set up, and can start
processing material within days of arrival on site.
These design considerations and factory
acceptance tests significantly reduce install time
and accelerate return on investment, the
company said.
Vallelly added: “Fast return on investment is a
very real proposition when the CDE AquaCycle
thickener is introduced to a washing operation. It
boosts the efficiency of the wet processing plant
by maximising the settlement of solids, which
reduces the quantity of flocculant required, cuts
running costs, and optimising the overall
efficiency of the plant.”
Return on investment with a CDE AquaCycle is
typically achieved in just six to nine months, says
CDE.
Settling ponds are known to be the source of
significant revenue losses, not only due to high
maintenance costs, site footprint, and downtime,
but also because high value fines can become
lost and trapped at the bottom of ponds.
Vallelly continued: “By recycling up to 90% of
process water, the requirement for settling ponds
is greatly reduced. With the addition of a filter
press tailings management system that need is
completely eliminated. When combined with a
CDE filter press custom-built fines management
system, this figure increases to 95%, removing
the need for settling ponds altogether.”
Long-term benefits
Water management systems are becoming a
must-have for mine and quarry operations to
comply with environmental regulations. Matters
concerning the protection of finite resources on
the planet will only become more prevalent,
too.
Vallelly concluded: “The benefits of the CDE
AquaCycle significantly outweigh their initial
investment; not only for the short period until
return on investment is achieved, but for the
preparedness it offers. Water management and
water recycling are prevalent issues that will only
become more tightly regulated and monitored in
years to come. The AquaCycle ensures operators
stay ahead of the curve while extracting
maximum value from available resources and
driving down operating costs.” IM