Authors: Labbett, DM; Swift, JD; Austin, PJ; Heath, AR; Francis, NS; Livk, I; Fawell, PD; Farrow, JB; Bui, A; Rudman, M
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Labbett, DM, Swift, JD, Austin, PJ, Heath, AR, Francis, NS, Livk, I, Fawell, PD, Farrow, JB, Bui, A & Rudman, M 2006, 'Optimising Flocculation and Thickener Performance for Paste Disposal', in R Jewell, S Lawson & P Newman (eds), Proceedings of the Ninth International Seminar on Paste and Thickened Tailings
, Australian Centre for Geomechanics, Perth, pp. 37-46.
The optimisation of thickener feedwells is often done to maximise throughput, i.e. achieving the best solids
settling flux through control of flocculation conditions and feedwell hydrodynamics. Changes in feedwell
design or the flocculant type, dosage and addition point can significantly alter the size of the aggregates
formed by feedwell flocculation and hence their settling rates. However, the resultant aggregate properties
also determine the solids fraction and rheology of the thickener underflow, and hence the propensity to
produce paste behaviour for a given thickener design and operating conditions. A focus of the AMIRA
P266D “Improving Thickener Technology” project was to understand the nature of aggregates formed within
full-scale thickener feedwells and their relationship to throughput, overflow clarity and underflow density,
through both laboratory studies and computational modelling (Farrow et al., 2000).
Understanding how permeability and compressibility parameters vary with solids concentration is crucial to
the modelling of thickener performance (Buscall and White, 1987). Despite this, there is little such
information for slurries flocculated under carefully controlled conditions. This paper outlines the
development of procedures to fully characterise these parameters and how they can be used to provide
insight into the way underflow properties are affected by the initial flocculation conditions.
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