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FLOTATION frothers. G flotation = G final - G initial = [ sg - ( sl + lg )] A. sg = sl + lg cos . w hen = 0 o , cos = 1, G flotation = 0, no flotation w hen = 90 o , cos = 0, G = - l g . full flotation
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FLOTATION frothers
Gflotation= Gfinal- Ginitial = [sg - (sl+ lg)] A sg = sl+ lgcos when = 0o, cos = 1, Gflotation= 0, no flotation when= 90o, cos = 0, G = -lg. fullflotation Thus, flotationreagentscan be classifiedinto • collector (decreases G) • frother (no ornegligablechange of G) • depressor (increases G)
FROTHERS Role of frother 1. Gas dispersion 2. Froth formation 3. Speeding up flotation 4. Improvingselectivity of flotation (by interaction with collector)
FROTHERS frother structure with depth
frother structure H. Khoshdast, A. Sam,Flotation Frothers: Review of Their Classifications, Properties andPreparation, The Open Mineral Processing Journal, 2011, 4, 25-44 25, 1874-8414/11 2011
Other classifications of frothers H. Khoshdast, A. Sam,Flotation Frothers: Review of Their Classifications, Properties andPreparation, The Open Mineral Processing Journal, 2011, 4, 25-44 25, 1874-8414/11 2011
Neutralfrothersapplied in flotation Laskowski, 1988 (with somemodifications) FROTHERS
Other classifications of frothers Frothersclassification (Lekki and Laskowski, 1974)
Properties of frothers CMC MIBC – metyloizobutylokarbinol CMC – criticalmicellizationconcentration Collector ions can be present in aqueous solution as free ions(a), premicellar species, (b)spherical micelles (c). Structures appear with increasing surfactantconcentration in aqueous solution. Symbol o denotes ion appositively charged to surfactantion
CCC Properties of frothers DF250 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. CCC95denotes 95% in Sauter mean bubble size reduction compared to mean bubble size in water only. Plotted by Kowalczuk, Ind. Eng.Chem. Res., 2013
in flotationimportantisdynamicsurfacetension Atrafi et al., 2012, MineralEng., vol. 36-38, 138-144
CCC vs frother dose Relationshipbetweenflotationselectivitycoefficienta and concentration of CxPyfrother. ppm = g/dm.Notelocation of CCC. Kowalczuk, Ind. Eng.Chem. Res., 2013
HLB (Hydrophobic - Lipophilic balanse) HLB = 7 + hydrophilicgroups – lipophylicgroups Hydrophilicgroups -O- 1.3 -OH (free) 1.9 -OH (sorbitan ring) 0.5 -SO4Na 38.7 -COOK 21.1 -COONa 19.1 -COOH 2.1 -SO3(H) (sulfonate) ~11 -tertiary amin 9.4 -ester (free) 2.4 Lipophilicgroups -CH, –CH2–, CH3–, =CH–0.475 -(CH2-CH2-CH2-O–) 0.15
CCC vs HLB Kowalczuk, Ind. Eng.Chem. Res., 2013
DFI and other Comparison of differentfrothersproperties (DI, CCC, Jw) and ability to mechanicalflotationmax. Theyaresimilar (Szyszka et al., 2008)
Quartzflotation in the presence of differentfrothers (Szyszka et al., 2008)
a– selectivitycoefficient of flotation – useful component recovery in concentrate r – non-usefulcomponentsrecovery in tailing Drzymala, unpublished , 2013
Frother properties Zhang, W., Nesset, J.E., Rao, R., Finch, J.A., 2012, Minerals, 2, 208–227.