Chapter 4
kaolinite at the bottom. The third and fourth bottles are the samples with 100 ppm
sodium naphthenate adding 0.6 mM NaOH (24 ppm) or 0.3 mM Na2SiO3 (37 ppm),
respectively. These two samples have similar separation results to the second
sample. Comparing the first sample and other samples, adding naphthenate
changes the wettability of kaolinite to more oil-wet. In the last three samples,
some of the kaolinite becomes partially oil-wet and stays in the upper oil-in-water
emulsion layer.
! A ‘4 ;
No Naphthenate With Naphthenate 0.6 mM NaOH 0.3 mM Na2SiO3
pH 8.3 8.3 9.0 9.0
Figure 4.2 Separation of toluene-brine mixture with 1.0 % kaolinite
Figure 4.3 shows water-wet fraction of kaolinite in the samples with 1.0 w.%
kaolinite in toluene-brine mixture (1:1, v∕v). The first bar is water-wet fraction (96%)
in the sample without sodium naphthenate at pH 8.3. Almost all the kaolinite is
water-wet in absence of naphthenate.
The second bar is water-wet fraction (18%) in the sample with 100 ppm
sodium naphthenate at pH 8.3. In this case, water-wet fraction is much Iowerwith
the presence of naphthenate. This indicates naphthenate can change the
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