High Quality Content by WIKIPEDIA articles! Raffinating something is a technique used in metallurgy to remove impurities from liquid material. There are many different kinds of raffination, for example you can use vacuum to extract hydrogen from metals. In solvent extraction, a raffinate is a liquid stream that remains left after the extraction with the immiscible liquid to remove solutes from the original liquid. From French raffiner, to refine. In solvent extraction, the two liquids must be immiscible. This will allow separation of the product rich extract and the depleted raffinate.