Correlating Mineral Surface Energy and Flotation Response Presented by: Syed Saad Ali Supervisor: Prof. Kristian Waters Department of Mining & Materials Engineering, McGill University Introduction Wettability and Surface Energy Results • Flotation is a physico-chemical separation • Wettability: measure of solid-liquid intermolecular • Figure 2 shows the Flotation Recovery Percentage against the Wadh at a surface coverage of 0.15 for galena, quartz and galena conditioned in KAX technique that utilizes the differences in wettability interaction; characterized by Work of Adhesion (Wadh) of different materials • Surface energy: dependent on the types of interactions 65.00 Galena yt 102 • Used in the mining industry to separates valuable occurring, and the chemical groups present, at the ) Galena 2 60.00 100 minerals in ores from gangue (waste material) surface Quartz yt 98 ) 55.00 2 Quartz • An estimated 450 million tons/yr of minerals are • 2 components of surface energy: dispersive/non-polar 96 Condioned 1 d + - 50.00 94 processed using froth flotation (γ ) and specific/polar (γ & γ ) Galena yt Condioned 45.00 92 galena (KAX) • However, the principles of flotation are poorly • The higher the solid surface energy, the higher the 90 40.00 understood Wadh and the wettability (more hydrophilic) 88 35.00 Wadh (mJ/m • There is room for process optimization and W = 2[(γ d*γ d)1/2 + (γ +γ -)1/2 + (γ -γ +)1/2] 86 adh s L S L S L 30.00 Surface Energy (mJ/m 84 improved separation, yielding significant economic Where γ = solid surface energy S 25.00 82 benefits 4 γL = liquid surface tension 0 0.1 0.2 0.3 0.4 0 20 40 60 Objective Frac4onal Surface Coverage Flota4on Recovery (%) Equipment • To optimize the procedure for surface energy Figure 5: Plot of Surface energy vs. Frac. Surf. Figure 6: Plot of Wadh vs. Flotaon Recovery for measurement using inverse gas chromatography Coverage for galena and quartz galena, quartz and condi/oned galena • To determine the correlation between the measured Conclusions surface energy and the flotation response of an ore • Accurate mineral surface energy measurements may be obtained using the SEA Froth Flotation • There is evidence of a direct positive correlation between the Work of Adhesion with water of a mineral and its flotation response • Air is bubbled through a mineral ore/water suspension in an agitated flotation cell Future Work • Hydrophobic (non-wettable) particles attach to air • Repeat the experiment with other sulphide and oxide minerals bubbles and are collected in the froth at the top of Figure 3: Surface Energy Analyzer Figure 4: Microflotaon Cell 6 • Investigate the effect of mineral oxidization the cell Schemac • The Surface Energy Analyzer (SEA) is an inverse gas • Hydrophilic (wettable) particles remain in the chromatography Acknowledgements suspension and are removed as tailings • It analytically determines surface energy using • The McGill Summer Undergraduate Research in Engineering Program • Various surfactants are used to alter surface retention time data of various vapour probes as they properties and control separation • Mr. Ray Langlois, Ms. Monique Rindeau & Dr. Mitra Mirnezami for their pass through a column containing the solid particles assistance with the experimental setup • The microflotation cell is then used to determine flotation response via small-scale flotation References 1- American Chemical Society. ‘New Technology for Recovering Valuable Minerals Experimental Methods from Waste Rock’. ACS News Service Weekly PressPac (2011) • A hydrophobic ore (galena) and a hydrophilic one 2- Encyclopedia Britannica. ‘Flotation’. Retrieved on 7th August from <http:// (quartz) are tested www.britannica.com/EBchecked/topic/210944/flotation> • Ore samples were crushed to -75 µm 3- Coleman, R. ‘Flotation cells: Selecting the correct concentrate launder design’. • 2-3g of sample is used to make an SEA column for Filtration and Separation, Vol. 46 Issue 6 (2009) 36-67 surface energy analysis, giving a total particle surface 4- Khoo, J. ‘iGC SEA Basic Principles and Applications’. Seminar - Surface area of ~0.5 m2 in the column Measurement Systems (2011) Figure 1: Schemac of a Flotaon Figure 2: Top View of an Industrial • 1 g of the sample was placed in the microflotation cell 6- Rehman, M. et al. ‘Optimization of powders for pulmonary delivery using Cell2 Flotaon Cell3 for 1 minute and the recovery percentage calculated supercritical fluid technology’. Eur. Jrn. of Pharm Sci, Vol. 22 Issue 1 (2004) 1-17 .