Fresh primary froth

Table n. Viscosities, Densities, and Compositions of Some Fresh Primary Froths by On-Line Measurements... 

Composition and Density. Density is of fundamental importance to any flotation process. The density of bitumen is much less variable and less dependent on temperature than on its viscosity. Thus, the density data reported by Ward and Clark (41) and Camp (22) shows slight temperature dependence for Athabasca bitumens. However, the density of froth is strongly influenced by the gas phase and also the entrained solid particles. Primary froth typically has a composition of 66% bitumen, 25% water, and 9% solids, and secondary froth typically contains 24% bitumen, 59% water, and 17% solids. Table II shows a series of freshly formed primary froth densities that vary from 0.7 to 0.9 g/cm3 at about 70 °C (the experimental conditions are described later). 

Fresh froth viscosities can be quite high compared to that of bitumen at the same temperature, primary froth having a viscosity of typically 1.8 to 3.0 x 103 mPa-s at about 80 °C (shear rate of 58 s-1), compared to a bitumen viscosity of 495 mPa s under the same conditions. 

In an attempt to obtain more reproducible, more representative data for freshly produced froth, some on-line measurements for continuously produced primary froth have also been made. The processing was carried... 

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