Separation of Oil-Contaminated Glass Grinds by Supercritical Fluid Extraction (SFE)

An extraction method is presented which relies on supercritical carbon dioxide as extractant. The development of the method and its demonstration in a bench-scale facility are described by the example of residues with high mineral oil and lead contents from machining optical glasses, the so-called glass grinds. By the extraction method, the oil can be recovered from the grinds in such a quality that direct recycling as grinding oil is possible.