Purificn. of soils contaminated with hydrocarbon(s) - by crushing, predrying, solvent extn. and post-drying

摘要

A process for purificn. of soils contaminated with aliphatic, aromatic and/or halogenated hydrocarbons is new. The process is carried out, after mechanical comminution and pre-drying, by homogenising in closed circuit with a solvent of n-pentane, petroleum ether, hexane or the like, moving the mixt. upwardly by a screw conveyor through an inclined reactor vessel having a bottom screen for sepn. of the contaminant/solvent mixt. and then post-drying, all the process steps involving solvent (vapour) being carried out under vacuum. The contaminated soil is comminuted to a particle size of max. 3 mm and its fines content is restricted to max. 30% (on dry basis) prior to pre-drying to a residual water content of max. 8%, the homogenised liq.-solids mixt. being subsequently sieved in the reactor vessel with a screen of max. 50 microns mesh (claimed). The appts. for carrying out the process is also claimed. ADVANTAGE - The process has low equipment costs and provides inexpensive soil decontamination.