Flotation of fine minerals: Novel temperature responsive polymer as flocculant and collector

Project Leader: George Franks
Staff: Luke Connal
Collaborators: Liza Forbes (CSIRO)
Primary Contact: George Franks (gvfranks@unimelb.edu.au)
Disciplines: Chemical & Biomolecular Engineering
Domains: Convergence of engineering and IT with the life sciences
Research Centre: Particulate Fluids Processing Centre (PFPC)

Froth flotation is an efficient method for selectively recovering valuable mineral particles in the range 50 to 200 microns, but low collection efficiency is observed for fine particles < 50 microns. Conventional flotation reagents are typically low molecular weight surfactants. These molecules specifically adsorb to the valuable mineral, rendering it hydrophobic. The low molecular weight surfactants are not good at aggregating fine particles and as such they are not collected. It would be of significant financial advantage to be able to recover fine minerals for sale, especially as the increasing reliance on low grade ores requires additional grinding in order to liberate the valuable mineral. The Franks group at the University of Melbourne has developed temperature responsive flocculants based on poly (N-isopropyl acrylamide) (PNIPAM) over the past few years.1-3 In addition to aggregating the fine primary particles into aggregates with optimum size suited for flotation, the surface of the particles is rendered hydrophobic, so the aggregates can be collected by flotation.4-6 The aim of this PhD project is to investigate the use of temperature responsive polymers as flotation reagents. In addition to mineral flotation experimentation, polymer synthesis will be expected of the student in order to develop novel reagents with specificity towards sulphide and oxide minerals.  Fine iron ore is one specific example of a mineral separation which can be investigated. Copper sulfides is another example.

Students with degrees in Minerals Processing or Chemical Engineering are encouraged to apply, especially those with experience in flotation or flocculation. The project is to be conducted in collaboration with the CSIRO (Australian National Laboratory) in Clayton Victoria.  

For technical information on the project, contact the academic supervisors, Prof. George V. Franks, gvfranks@unimelb.edu.au  and Dr. Liza Forbes (CSIRO), elizaveta.forbes@csiro.au.

1) G. V. Franks, “Improved Solid/Liquid Separation using Stimulant Sensitive Flocculation and Consolidation”, Journal of Colloid and Interface Science,292, 598-603 (2005). 

2) H. Li, J.-P. O’Shea and G. V. Franks, “Effect of Molecular Weight of Poly(N-isopropylacrylamide) Temperature-Sensitive Flocculants on Dewatering”, AIChE Journal, 55 [8] 2070-2080 (2009).

3) J.-P. O’Shea, G. G. Qiao and G. V. Franks, “Solid-liquid separations with a temperature-responsive polymeric flocculant: effect of temperature and molecular weight on polymer adsorption and deposition”. Journal of Colloid and Interface Science, 348, 9-23 (2010).

4) Burdukova, H. Li, N. Ishida, J.-P. O'Shea and G. V. Franks, “Temperature Controlled Surface Hydrophobicity and Interaction Forces Induced by Poly (N-Isopropylacrylamide)”, Journal of Colloid and Interface Science, 342, 586-592 (2010).

5) G. V. Franks, H. Li, J.-P. O’Shea and G. Qiao, “Temperature responsive polymers as multiple function reagents in mineral processing”, Advanced Powder Technology, 20, 273-279, (2009).

6) E. Burdukova, H. Li, D. Bradshaw and G. V. Franks, “Poly (N-isopropylacrylamide) (PNIPAM) as a flotation collector: effect of temperature and molecular weight”, Minerals Engineering, 23, 921-927 (2010).