Anionic flocculants

Polymeric flocculants are available in various chemical compositions and molecular weight ranges, and they may be nonionic in character or may have predominantly cationic or anionic charges. The range of application varies but, in general, nonionics are well suited to acidic suspensions, anionic flocculants work well in neutral or alkaline environments, and cationics are most effective on organic material and colloidal matter. 

Mineral segregation in industry relies heavily on the selective adsorption of macromolecules onto the surfaces of those minerals that have particular industrial applications. This selectivity is governed mainly by the surface chemistry of the mineral and the type of polymer used as a flocculant. " Effectiveness of flocculation depends upon the charge, concentration and molecular weight of the polymer, and also the pH and salt concentration of the clay suspension. The bonding between the anionic flocculant polyacrylamide (PAM) and clay mineral surfaces has been effectively reviewed recently by Hocking et al and the reader is referred to this should they require an in-depth literature review. For more information on general colloidal chemistry of clay suspensions the reader is referred to the review of Luckham and Rossi." ... 

Acrylamide/amine copolymers (+ amine deriv.) Anionic flocculants... 

The order of effectiveness for cations does not support this interpretation. The strongly hydrated lithium ion, for example, was the least potent of the monovalent cations studied. Moreover, the highly hydrated divalent cations were also relatively poor flocculants. We also note that the most effective anionic flocculant, S04, is only weakly hydrated, if it is hydrated at all. The results for both anions and cations suggest that flocculation is not induced simply as a consequence of the dehydration of the stabilizing moieties. 

Uses Comonomer (anionic flocculants/dispersants) protective colloid and/ or copolymerizable surfactant in actylic/modified acrylic latexes for use in paints, inks, adhesives, and sealants in food-contact paper/paper-... 

Empirical C7H13NO4S Formula H2C=CHCONHC(CH3)2CH2S03H Properties M.w. 207.25 m.p. 195 C Toxicology Cancer suspect agent Precaution Corrosive Uses Comonomer (anionic flocculants/dispersants) protective colloid and/or copolymerizable surfactant in acrylic/modified acrylic latexes for use in paints, inks, adhesives, and sealants in food-contact paper/paperboard Manuf./Distrib. ABCR UK http //www.abcr.de] Aldrich http //www.sigma-aidrich.com] CBC Europe Fisher Scientific UK http //www.fisher.co.uk, Fluka http //www.sigma-aidrich. com Lancaster Synthesis UK http //www.iancastersynthesis.com] Lubrizol... 

Flotation results show that the flocculation of polyacrylonitrile decreases obviously with introducing small amounts of -COOH groups. When the introduced quantity of -COOH groups is 1/3, however, the flocculation of polyacrylonitrile increases. When the introduced quantity of -COOH groups is 2/3, polyacrylonitrile appears an anionic flocculant which is similar to Aerofloc 550. 

PolyacryUc acid is a typical anionic flocculant which is able to flocculate the Ca, Mg, and Ba minerals under alkaline conditions. 

Other anionic flocculants comprise polyoxybenzyl cw-butenedioic acids, alginic acids, humic acids, anionic starchs, and mannogalactan. Other cationic flocculants mainly involve in guanidines, cationic starchs, and polyamines. 

With inorganic suspensions non-ionic and anionic flocculants generally... 

Field showed that a combined anionic flocculant/cationic coagulent system, at constant coagulent dose, performs better on coal-tailings than when flocculant alone is used. In general, it is the type of solid-liquid processes in use which dictate the molecular weight of the chosen electrolyte—see Table 4.5. On the other hand, the chemical type necessary generally depends on the slurry characteristics, i.e. solid chemical surface type, particle size distribution, the dissolved electrolytes and the pH. 

Flocculation by enlargement of the hydroxide floe on which the destabilized colloids or micelles are adsorbed. An anionic flocculant is often added. 

Coal tailings require the use of an anionic flocculant, albeit a relatively small amount, which is usually admitted upstream of the decanter, as in this case. The first four runs recorded were conducted at a standard bowl speed, giving just under 2400g gravitational field. The last six runs were when using a much lower gravitational field, under 1 OOOg. 

Neff RE, Pellon JJ, Ryles RG. Method of dewatering suspensions with unsheared anionic flocculants. US patent 5961840. 1999. 

Fig. 4. The variation of normalised resonant frequency with time for a 20% v/v kaolin/water suspension (density, 1370 kgm ) 17°C at various reed positions relative to the top of the settling zone Curve A, 699 mm Curve B, 900 mm Curve C, 1096 mm, Curve D, 1296 mm. Sedimentation is induced by adding 200 cm3 of a 5% wt/wt anionic flocculant (Magnafloc 155) solution to the suspension.

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