Aerated bitumen droplet density

The linear correlation between aerated bitumen droplet density and bulk froth density for this ideal system is illustrated in Figure 14. The intercept of this line is equivalent to the assumed void fraction, and the slope represents the volume fraction of the material occupied by the aerated bitumen droplets. Experimental data for mean particle diameter and froth bulk density obtained under a variety of process conditions could... 

Danielson (64) measured bitumen droplet densities and corresponding froth compositions for two oil sands of differing processibility. For one oil sand, the mode of the observed distribution of aerated bitumen droplet densities was 0.31 g/mL with the recovered froth found to contain 52.9% bitumen. For the other oil sand, the mode of the density distribution was 0.51 g/mL with a corresponding froth assay of 63.2% bitumen. Although these froth compositions are somewhat higher than those predicted from Figure 13, the trend toward improved froth quality with increasing droplet density is evident. 

Figure 13. Relationship between froth quality and aerated bitumen droplet density.

Figure 29. Relationship between froth quality and aerated bitumen droplet density showing model (solid curve) and experimental results (broken curve). (Adapted from Schramm [110]. Copyright 1994, American Chemical Society.)...

The packing density of aerated bitumen droplets at the froth interface is a function of droplet size distribution, the flux of material imping-... 

An attempt has been made to develop the hot-water process for the Utah sands (Fig. 10) (20). With od-wet Utah sands, this process differs significantly from that used for the water-wet Canadian sands, necessitating disengagement by hot-water digestion in a high shear force field under appropriate conditions of pulp density and alkalinity. The dispersed bitumen droplets can also be recovered by aeration and froth flotation (21). 

Calculations can be performed to show the expected relationships between froth quality, bitumen droplet aeration, and packing density for... 

Example. Bitumen is recovered in the form of a froth when a separation-flotation process is applied to surface mined oil sand. Once de aerated, this bituminous froth is a W/O emulsion from which the water must be removed prior to upgrading and refining. At process temperature (80 °C) the emulsion viscosity is similar to that of the bitumen, but the density, due to entrained solids, is higher. Taking t) = 500 mPa-s and f> = 1.04 g/mL, the rate of creaming of 20 pm diameter water droplets under gravitational force will be very slow ... 

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