Desalting of Bitumen in Upgrading facility

When bitumen is received by an upgrading facility, it is often accompanied by salt and water. In the desalter, bitumen is washed with fresh water, and a de-emulsifier is added to assist in phase separation. I have read that salt removal is challenging because salts are trapped within a bitumen coating. How did salts end up being trapped within a bitumen coating when water was used for bitumen recovery from subsurface (through steam injection) or through mining, where they were dissolved in water?

Emulsions of high-viscosity crude oil, like bitumen, are very stable and difficult to treat because the viscosity of the oil hinders the movement of dispersed water droplets, thus retarding their coalescence. Additionally, bitumen contains emulsifiers (e.g., asphaltenes). De-emulsifier, which is soluble in bitumen, is added to bring the suspended water droplets together into larger water droplet particles. However, since the density of water and bitumen is comparable, will phase separation take place, and how are the trapped salts released?