The name is absent

Chapter 5

skins in the rag layer, slides were prepared by sampling from different positions of
emulsion samples. The skins were observed for 10 minutes before adding NaOH.
Then NaOH was added at time zero. The pH of the aqueous phase was increased
from 8.5 to 9.5 by adding 0.1 M NaOH. Photomicrographs of clay solids skins
were taken as the function of time.

5.4.2. Results and discussions

Figure 5.3 shows the photomicrographs of clay solids skins with time when
increasing pH for 8.5 to 9.5 as described in section 5.4.1.

Before adding NaOH, the skins did not change in 10 minutes. After adding
NaOH, the skins became smaller gradually and disappeared. Finally, only clay
solids remained. Clay solids and the oil form rigid skins. Athabasca bitumen has a
relatively high acid number (total acid number 3.3 mg KOH/ g oil) ^[8]. With an
increase of pH, additional naphthenic acids in the oil form soaps and separate the
oil from clay solids. So increasing pH can break the skins.

Based on the discussion in section 5.3.2, sample 2 with silicate at initial pH
8.5 has the best emulsion separation results. In the second step, emulsion
samples were prepared starting with sample 2 of Table 5.1. After separating the
clean oil layer, five samples were prepared as described in section 5.4.1.

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