Final flocculant solution characteristics

Nothing has yet been said about the concentration of polymer required, as it is to be fed to the centrifuge. A level of 0.1% of active ingredient is very common and could be considered the norm. It is more common to quote solution strengths in terms of active ingredient, but polymers, which are supplied in solution or as a dispersion, are sometimes quoted in terms of percentage of as supplied . Care must then be taken when assessing performance. 

Because of the physical nature of the solid polymer, some suppliers add small amounts of chemicals to enhance the flow properties or aid dissolution. When assessing polymer dosage these additives also need to be taken into account. This again emphasises the need to record polymer dosage as kilograms of active ingredient per ton of dry solids in the feed, when assessing relative performance levels. 

The viscosity of a polyelectrolyte solution is a measure of not only its concentration, but also of the molecular weight of the polymer. Moreover, violent agitation, or circulating the solution under pressure through an 

The more dilute the polymer, the more efficiently it works, providing optimum mixing with the process liquor. However the bigger the difference between the viscosities of the polymer solution and the process liquor, the more difficult is the mixing. The higher viscosity component tends not to break up and disperse so easily as the other liquor. 

Another factor that affects the choice of the polymer concentration is the quantity to be used, compared with the quantity of process liquor. Once the size of the decanter has to be increased to cope with the extra volumetric load of the flocculant solution, then dilution has gone loo far. The flow of flocculant solution should be not more than, say, 10 or 1 5% of the feed rate, on this basis. 

---

A model of flocculent and dripless adsorptive layers also is good agreed with the experimental ellipsometric data on kinetics of adsorption of different upon nature and length polymieric chains and also on number and distribution in them of the functional groups [19-23], It is follows from these references that the kinetic curves of adsorption of the polymeric chains Ifom the diluted solutions consist of two sections the first is starting - quick and short with the characteristic time by 10 s order and the second one (final) - slow and long with the characteristic time... 

---