TREATMENT METHOD FOR SOIL POLLUTED WITH HEAVY METAL

摘要

PROBLEM TO BE SOLVED: To provide a treatment method for heavy metal-polluted soil which is capable of efficiently separating and removing particles containing heavy metals in a high concentration in the soil and recovering a large amount of cleaned soil.

SOLUTION: Soil polluted with heavy metals is sieved and soil with a particle size in a prescribed range is introduced into an attrition tank 5 and mixed with an insolubilization agent. Particles are abraded one another to separate pollutants adhering to the surface. After that, the particles are sent to a liquid cyclone 7 to take out particles from which the pollutants are separated as clean soil and the remaining fine particles are led to a centrifugal jig type specific-gravity separator 8. The centrifugal jig type specific-gravity separator 8 has a layer of particles with a prescribed diameter and separates the particles into a high specific gravity fraction containing a much amount of heavy metals passing through the layer by the centrifugal force and a low specific gravity fraction containing a little amount of heavy metals, and the high specific gravity fraction and particles with 30μm or smaller are discarded after dewatering with a dewatering means 10. The low specific gravity fraction is treated by a detoxification means 9 and turned back or discarded.

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