| 摘要 |
<p>Mercury-contaminated soil is treated in such a way that the mercury content is reduced from a maximum of 300 mg of mercury per kg of solids to less than 10 mg of mercury per kg of solids. To this end, the contaminated soil is fed in an essentially dry state to a sieve (7), the relatively fine material which has passed through the sieve is fed, together with water, a degreasing agent and a surface-tension-reducing agent, to a shaking table (1) of the Wilfley type, the discharge end of the connecting channel (7a) between sieve (7) and shaking table (1) being below the liquid level. The table (1) is shaken parallel to the ridges (2), the mercury concentrate separated off being discharged in the vicinity of a point essentially diagonally opposite the pulp feed and the treated material being collected in a gutter (4) at the said second side and fed via a pump (11) to at least one dewatering cyclone (12). The overflow material from the cyclone is fed to a thickener (20) in order to separate off suspended sludge particles smaller than 30 to 40 νm, and said water from which suspended sludge has been removed is recycled to the sieve (7) and/or shaking table (1).</p> |
