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I have a mixture that contains out of dirt/sand and salt. I want to extract and measure the salt. What would be the best way to extract the salt from this mixture?

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migrated from physics.stackexchange.com Apr 19 '16 at 0:16

This question came from our site for active researchers, academics and students of physics.

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Assuming you mean NaCl - the common "salt" (chemists call lots of things salt!).

If you extract the salt by physical means, it's a physics question.

Assuming that the "dirt" is not (or poorly) soluble in water, I would simply dissolve the salt in water, filter the liquid, then recrystallize (by evaporation of the liquid) and weigh the resulting crystals. Not sure if you call that chemistry or physics... it's physical chemistry. It is well described in text books and online - see for example this Scientific American page

Depending on how accurate you want to get, there are a slew of precautions to take. That would be the realm of the chemistry.stackexchange sister site.

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The question is very vague. Common road salt is typically $\ce{NaCl}$ or $\ce{CaCl2}$, both of which are soluble in water. The problem is that "dirt" could be anything, including lots of things that are also soluble in water.

So the idea that washing the mixture with water to remove the solutes would isolate the salt is insufficient. You would need to specify the type of salt you're dealing with and then ask on a chemistry forum how to chemically isolate just that compound.

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  • $\begingroup$ You're right, the question is vague. But, that is mainly because I didn't know what salt this was and what materials where in the "dirt". Turns out that it was just common table salt with some sand and small stones. Thanks for your answer. $\endgroup$ – bramhaag Apr 19 '16 at 11:41
  • $\begingroup$ @bramhaag , how did you know it was just NaCl and no other water soluble salts? $\endgroup$ – Technetium Apr 19 '16 at 12:28

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