The name is absent

Chapter 6

Ca/ Mg ions, and has little effect on pH of synthetic brine. Carbonate ion can
increase pH, bicarbonate ion concentration and precipitate Ca ions, which can
make zeta potential more negative.

6.1.3. Diluted bitumen emulsion separation

At 50 ^oC, diluted bitumen emulsion with dilution ratio 0.7 adding demulsifier
PRs produces incomplete separation with a rag layer between oil and water.
When a small amount of silicate is present in the water drops, the solid particles
are more water-wet and the volume of the rag layer is smaller. Optimal condition
of aqueous phase for emulsion separation is adding 1×10^⁴ M sodium meta-
silicate (Na₂SiOs) at pH 8.5.

If the clean oil is removed after this initial demulsification step and sodium
hydroxide is added to the remaining material with shaking to increase pH to 8.8,
the skins making up the rag layer are destroyed, an O∕W emulsion forms, and
nearly all of the solids are released to the aqueous phase. Finally, adding
hydrochloric acid to reduce pH to 5.0 breaks the O∕W emulsion. This three-step
procedure yields nearly complete separation of water, diluted bitumen and solids.

Karl Fischertitration can be used to measure water content in diluted bitumen.
Toluene-methanol mixture with toluene volume ratio 75 % is the appropriate
solvent for the titration of water in diluted bitumen. This method only needs small

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