Kinetics of Heavy Metals Leaching from Contaminated Soils in Metallurgical Plants Paolo Desogus , Pier Paolo Manca , Giampaolo Orrù Abstract The work aims to highlight the main parameters that affect the efficiency of the process of leaching of heavy metals from a natural soil taken from inside a metallurgical plant. The studies were conducted by laboratory tests and the results will allow identifying the fundamental choices for the applications of the technique of in situ soil flushing. The tested soil samples were mainly made by fine silica sand, with medium density. Their pollution was caused by waste of the metallurgy of lead and zinc released into the soil to transport by rainwater. Their depth ranges from 1 to 2 meters from ground the level from which they are separated by artificial strata composed of soil mixed with metallurgical solid waste. The layer of soil tested hosts an aquifer with a slow permeability, variable depth generally higher than 10m contaminated by heavy metals. The leaching experiments were conducted through the batch and column tests. Acid solutions (acetic. nitric. hydrochloric and sulfuric) were used as extracting agents. During the leaching tests, concentrations of analytics Zn, Pb, Cd, Cu, Mn and Al were verified. The results highlighted two aspects: (a) the conditions for which they get the best efficiency of leaching and (b) the laws of statistical correlation that describe the kinetics of reaction. The calculations performed have shown that the most efficient leaching agent was the CH3COOH and mainly the flow velocity of the leaching solution conditions the reaction kinetics in the column.
Kinetics of heavy metals leaching from contaminated soils in metallurgical plants
MANCA, PIER PAOLO;
2011-01-01
Abstract
Kinetics of Heavy Metals Leaching from Contaminated Soils in Metallurgical Plants Paolo Desogus , Pier Paolo Manca , Giampaolo Orrù Abstract The work aims to highlight the main parameters that affect the efficiency of the process of leaching of heavy metals from a natural soil taken from inside a metallurgical plant. The studies were conducted by laboratory tests and the results will allow identifying the fundamental choices for the applications of the technique of in situ soil flushing. The tested soil samples were mainly made by fine silica sand, with medium density. Their pollution was caused by waste of the metallurgy of lead and zinc released into the soil to transport by rainwater. Their depth ranges from 1 to 2 meters from ground the level from which they are separated by artificial strata composed of soil mixed with metallurgical solid waste. The layer of soil tested hosts an aquifer with a slow permeability, variable depth generally higher than 10m contaminated by heavy metals. The leaching experiments were conducted through the batch and column tests. Acid solutions (acetic. nitric. hydrochloric and sulfuric) were used as extracting agents. During the leaching tests, concentrations of analytics Zn, Pb, Cd, Cu, Mn and Al were verified. The results highlighted two aspects: (a) the conditions for which they get the best efficiency of leaching and (b) the laws of statistical correlation that describe the kinetics of reaction. The calculations performed have shown that the most efficient leaching agent was the CH3COOH and mainly the flow velocity of the leaching solution conditions the reaction kinetics in the column.
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