FLOTATION frothers

when  = 0 o, cos  = 1,  G flotation = 0, no flotation when  = 90 o, cos  = 0,  G = -  lg. full flotation Thus, flotation reagents can be classified into a)collector (decreases  G) b)frother (no or negligable change of  G) c)depressor (increases  G)  G flotation = G final - G initial = [  sg - (  sl +  lg )] A  sg =  sl +  lg cos 

Role of frother 1. Gas dispersion 2. Froth formation 3. Speeding up flotation 4. Improving selectivity of flotation (by interaction with collector)

frother structure with depth

frother structure H. Khoshdast, A. Sam, Flotation Frothers: Review of Their Classifications, Properties and Preparation, The Open Mineral Processing Journal, 2011, 4, , /

Other classifications of frothers H. Khoshdast, A. Sam, Flotation Frothers: Review of Their Classifications, Properties and Preparation, The Open Mineral Processing Journal, 2011, 4, , /

Neutral frothers applied in flotation Laskowski, 1988 (with some modifications)

Other classifications of frothers Class Property of aqueous solution Liquid-gas interactions at flotation concentrations Froth/foam Surface active Form colloidal solutions (fatty acids amine, sulfonates, sulfates) Stronly reduce water surface tension Form two (foam) and three (froths) phase systems Form true solutions (alcoholes) Change aqueous surface tension Form two (foam) and three (froths) phase systems Surface inactive Organic compounds forming true solutions (ethyl acetal, ethyl diacetone) Do not change aqueous surface tension Form only three phase system (froth) Inorganic electrolyties Increase surface tension of water Form weak foams and strong froths with hydrophobic particles Frothers classification (Lekki and Laskowski, 1974)

CMC – critical micellization concentration MIBC – metyloizobutylokarbinol Properties of frothers CMC Collector ions can be present in aqueous solution as free ions(a), premicellar species, (b) spherical micelles (c). Structures appear with increasing surfactant concentration in aqueous solution. Symbol o denotes ion appositively charged to surfactant ion

Properties of frothers CCC Data of Finch, J.A., Nesset, J., Acuna, C., 2008, Role of frother on bubble production and behaviour in flotation, Miner. Eng., 21, 949–957. CCC 95 denotes 95% in Sauter mean bubble size reduction compared to mean bubble size in water only. Plotted by Kowalczuk, Ind. Eng.Chem. Res., 2013 DF250

Atrafi et al., 2012, Mineral Eng., vol , in flotation important is dynamic surface tension

Relationship between flotation selectivity coefficient a and concentration of C x P y frother. ppm = g/dm. Note location of CCC. Kowalczuk, Ind. Eng.Chem. Res., 2013 CCC vs frother dose

HLB (Hydrophobic - Lipophilic balanse) HLB = 7 + hydrophilic groups – lipophylic groups Hydrophilic groups -O OH (free) 1.9 -OH (sorbitan ring) 0.5 -SO 4 Na COOK COONa COOH 2.1 -SO 3 (H) (sulfonate) ~11 -tertiary amin 9.4 -ester (free) 2.4 Lipophilic groups -CH, –CH 2 –, CH 3 –, =CH– (CH 2 -CH 2 -CH 2 -O–) 0.15

HLB Application Antifoaming reagents 3,5-6 Emulsification reagents 4-10 Frothers 7-9 Wetting reagent s 8-18 Emulsifikation reagents (oil in water) Detergents Solubilization reagents Application of surfactants depending on their HLB

CCC vs HLB Kowalczuk, Ind. Eng.Chem. Res., 2013

DFI and other Comparison of different frothers properties (DI, CCC, J w ) and ability to mechanical flotation  max. They are similar (Szyszka et al., 2008)

Quartz flotation in the presence of different frothers (Szyszka et al., 2008)

Drzymala, unpublished, 2013

a – selectivity coefficient of flotation  – useful component recovery in concentrate  r – non-useful components recovery in tailing Drzymala, unpublished, 2013

Frother familyTypenmHLBMW g/mol CCC 95, mmol/dm 3 Aliphatic alcohols C n 1-Propanol Butanol Pentanol Hexanol Heptanol Octanol Propanol Butanol Pentanol Hexanol Heptanol Octanol Pentanol Hexanol Propylene glycol ethers C n P m Propylene glycol methyl ether Propylene glycol propyl ether Propylene glycol butyl ether Di(propylene glycol) methyl ether Di(propylene glycol) propyl ether Di(propylene glycol) butyl ether Tri(propylene glycol) methyl ether Tri(propylene glycol) propyl ether Tri(propylene glycol) butyl ether Polypropylene glycols P m Di propylene glycol Tri propylene glycol Tetra propylene glycol Poly propylene glycol Poly propylene glycol Poly propylene glycol Commercial FX DowFroth 250 DF DowFroth 1021 DF FX FX F F Frother properties Zhang, W., Nesset, J.E., Rao, R., Finch, J.A., 2012, Minerals, 2, 208–227.