Recovering solvent from waste with prodn. of dry granular or powdery residue - by adding urethane! foam powder as detackifier before vacuum distn. and drying, allowing washings from lacquering, degreasing or cleaning solns. to be recycled

摘要

In the distn. and drying of waste solvent, an additive is used to detackify the distn. residue, so that pure solvent and a granular or powdery residue are obtd. simultaneously. Before distn., the waste is treated with 5-20 wt.% of polyurethane foam powder with a density of 20-150 kg/m3 w.r.t. the solids content of the solvent; most of the solvent is distilled off at 40-100[deg]C and 0.5-1 bar; and the residue is dried further at 80-100[deg]C and 0.05-0.5 bar.