The hotter it is the quicker water will evaporate.
To get water back from a solution, first to evaporate the water and then you condense the vapour on something cool.
To separate solids of different sized dry particles you sieve.
To separate an insoluble solid from a liquid you filter it.
To separate an insoluble solid from a soluble solid of similar sized particles you mix them with water and filter the insoluble solid out and then evaporate the solution to get the soluble solid back.
To separate a mixture of Iron filings from another solid, you can use a magnet. The magnet will attract the iron and leave the other solid behind.
