We just learned about the Oil Refinery.
One part of refining oil is called a Desalter.
When crude oil comes out of the ground it has a bunch of chemicals in it that need to be removed to make it more useful.
Usually oil ends up getting mixed up with water which can have a lot of other things mixed in it like calcium, sodium and magnesium chlorides.
These are all called salts, and aren't the same as the salt you eat but they have to be removed from the oil.
The crude oil gets heated up really hot and then mixed with some fresh water.
It gets pumped into another tank that uses electricity to get the water and salts to go to the bottom of the tank and get separated from the oil.
The desalted oil on top then gets pumped out.
(from: wikipedia - desalter)
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