Removing chemical contaminants from sandy soil - by treating with contaminant-dissolving additive, and washing with water passing upwards through sieve to suspend particles

摘要

Process for cleaning sand-contg. soil contaminated by chemicals comprises (1) mixing a quantity of the soil with an additive which dissolves the contaminant(s), (2) washing the soil with water by placing it in a sieve, passing water upwards through the sieve in rapid laminar flow such that the particles of soil become suspended, and (3) draining the water off rapidly through the sieve. A gas such as air may be introduced into the wash water flowing up through the sieve. The soil may be mixed with the additive prior to being placed on the sieve, or the soil may be placed on the sieve untreated and the additive added to the water. The process is esp. useful for cleaning soil on land which is to be reclaimed and which is contaminated by cyanides (e.g. from gas works, plating residues, etc.), heavy metals, etc. During the washing stage on the sieve, the sand particles become sepd. from the clay, then on rapid draining, the sand forms a filter bed on the sieve through which the water drains away from the sand and clay rapidly and completely.