A PROCESS FOR SEPARATING A CONTAMINATING SUBSTANCE FROM A MATERIAL CONTAMINATED BY SAID SUBSTANCE

摘要

A method of separating a contaminating substance, e.g. PCB, mercury, from a material contaminated with said contaminating substance, e.g. soil. The method involves heating the contaminated material in a first separation process and treating said material with a recirculating gas which is caused to pass repeatedly through the material in a closed circuit, a main loop (23), during the process while increasing in temperature to the boiling point of the contaminating substance present in said material, so that said contaminating substance will be successively expelled from the material and enriched in vapour phase in the recirculating gas. The expelled and enriched contaminating substance is separated from the gas in a second separation process carried out in a sub-flow loop (27). Any thermal energy that is released during the second separation process is returned to the closed circuit (23) and therewith supplied to the first separation process.