Purificn. of contaminated grainy material such as soils

摘要

Purificn. process for contaminated grainy material, esp. soils, involves: classification of a fed contaminated grainy material by sieving off at least one coarse material; washing of the fine fraction using high pressure water streams, settling and/or decelerating the wash mixt. of grainy material, water and air by passing it through a run out stretch; conveying the solid portion of the mixt. onto a wash sieve to sieve off at least one fine grain portion under 100 mu m contg. the sepd. contaminants; rinsing the sieve overflow contg. purified material; and separate collection of the purified material, contaminant contg. fine grain material and used wash water. The feed material classification may proceed with a sepn. of a coarse fraction above 20 mm. The fine material may be put under stress during washing by multistage high pressure water streams, these operating at up to 800 bar. The fine fraction may be pre-homogenised before the wash process by elutriation. During settling and/or deceleration of the wash mixt., the air portion may be sepd.. The solid portion of the wash mixt. may be sepd. in a multistage sieve with three sieve stages for overflows of above 300 mu m, above 150 mu m, and above 50 mu m. The various sieve overflows may be brought together and washed again. The sieving of the sieve overflows may proceed with wash water spraying. The used wash water may be collected and sent to water processing.