The influence of flocculant adsorption kinetics on the dewaterability of kaolinite and smectite clay mineral dispersions

McFarlane, Angus, Yeap, Kai Ying, Bremmell, Kristen and Addai-Mensah, Jonas (2008) The influence of flocculant adsorption kinetics on the dewaterability of kaolinite and smectite clay mineral dispersions. Colloids and Surfaces A: Physicochemical and Engineering Aspects, 317 1-3: 39-48. doi:10.1016/j.colsurfa.2007.09.045


Author McFarlane, Angus
Yeap, Kai Ying
Bremmell, Kristen
Addai-Mensah, Jonas
Title The influence of flocculant adsorption kinetics on the dewaterability of kaolinite and smectite clay mineral dispersions
Journal name Colloids and Surfaces A: Physicochemical and Engineering Aspects   Check publisher's open access policy
ISSN 0927-7757
1873-4359
Publication date 2008-03-20
Year available 2007
Sub-type Article (original research)
DOI 10.1016/j.colsurfa.2007.09.045
Volume 317
Issue 1-3
Start page 39
End page 48
Total pages 9
Place of publication Amsterdam, Netherlands
Publisher Elsevier BV
Language eng
Formatted abstract
Polymer mediated flocculation is central to efficient water recovery from and impoundment volume reduction of mineral waste tailings, particularly where clay minerals comprise a significant proportion. In this study, the adsorption kinetics of four high molecular weight polymeric flocculants onto colloidal, negatively charged kaolinite and smectite clay substrates under orthokinetic conditions has been investigated. For both kaolinite and smectite surfaces, the adsorption rate decreased in the sequence: non-ionic polyacrylamide homopolymer (PAM N) > anionic polyacrylamide-acrylate copolymer (PAM A) > non-ionic polyethylene oxide (PEO) > anionic polyacrylamide 2-acrylamido 2-methylpropane sulphonate copolymer (PAM S). Upon flocculation under laminar flow conditions, optimum subsidence rates for both clay types decreased according to flocculant type in the order PAM S > PEO > PAM A > PAM N, implying slower polymer adsorption rate facilitated higher floc settling behaviour. Calculation of first order rate constants for the adsorption of PAM N, PAM A and PAM S onto kaolinite at 25 °C and 50 °C and subsequent estimation of an activation energy in the range 14–22 kJ mol−1 polymer suggest that the overall energy is distributed among the transition state hydrogen bonds which are PAM polymer structure independent. Rationalisation of the results suggests that under industrially relevant conditions, flocculants with relatively slower tails’ particle attachment kinetics facilitate improved bridging performance and markedly enhanced settling behaviour.
Keyword Adsorption kinetics
Polyelectrolyte
Flocculation
Dewatering
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Unknown
Additional Notes Available online 13 October 2007

Document type: Journal Article
Sub-type: Article (original research)
Collection: Julius Kruttschnitt Mineral Research Centre Publications
 
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Created: Tue, 09 Aug 2011, 15:44:19 EST by Karen Holtham on behalf of Julius Kruttschnitt Mineral Research Centre