Division of Information Technology, Engineering and the Environment
Applied Centre for Structural and Synchrotron Studies
Applied Centre for Structural and Synchrotron Studies
Project duration: 2004-2007
Client: Rio Tinto
Chief Investigators: Gayle Morris*, Marek Zbik*, Roger Smart
Description:
Flocculation and
dewatering of slurry streams containing significant proportions of
clays (particularly kaolin and smectites) is becoming increasingly
urgent in view of the growing demand for high density disposal of
mining slurries, tailings and other mineral wastes. Mine tailings
are often disposed of as high water content slurries (e.g. >75 wt%)
into tailing dams. Release of water, for recycle and reduced make-up
water consumption, from these slurries in tailings streams and beds
is usually slow and incomplete. Because clay particles are extremely
small, generally <200 nm, natural separation by sedimentation is
very slow.
Flocculation is achieved using long chain polymers however the role
of aggregation prior to flocculant addition is not well understood.
Our research during the recent collaborative project has indicated
that this aggregation region is where large gains in efficient
dewatering can be made. The structure of aggregates formed before
flocculant addition is understood to be determinative of the
sedimentation rate, the final bed density and the retained water
after drainage. This is where the focus of this project lies.
The project therefore has two sets of aims.
Mechanistic understanding of aggregate formation and change.
including interparticle forces, aggregate compressibility, manipulation
Control of these processes in practice.
including study of actual aggregate structures in different tailings, toolkit application, and trials of aggregate structural change.
* Ian Wark Research Institute
