Enhanced Soil Washing for the Remediation of a Brownfield Polluted by Pyrite Ash
Journal article, 2017

Soil from an abandoned/disused fertilizer plant polluted with pyrite ash containing heavy metal(loid)s (As, Cu, Pb, and Zn) was treated by means of physical and chemical washing. We first performed an exhaustive characterization of the soil-pollutant interaction, which allowed us to determine the chemical nature (complex oxyhydroxides), potential mobility and bioavailability of the pollutants (very low), as well as the grain size fractions of preferential accumulation (silt-clay fraction comprises more than 60% of the material and revealed contents well above 2.000 ppm of Cu, Zn and Pb). Soil/ash samples were subjected to a number of chemical washing trials, including leaching with 2 M HCl, 2 M NaOH and acidic process water (pH around 0). The fraction below 63 µm was mechanically separated and exposed to additional leaching tests e.g. chloridizing roasting with NaCl plus water leaching. Of all the tested procedures, the latter proved the most effective, particularly with regard to Cu and Zn recovery (recoveries up to 40% and 34%, respectively). The information gathered offers an insight into the modes and rates at which metals can be leached from pyrite ashes after chloridizing roasting as a prelude to more extensive soil washing feasibility studies focused on potential metal recovery.

Pyrite ash

soil washing

leaching

chloridizing roasting

brownfield

Author

Karin Karlfeldt Fedje

Chalmers, Civil and Environmental Engineering, Water Environment Technology

C. Sierra

University of Cantabria

J. R. Gallego

University of Oviedo

Soil and Sediment Contamination

1532-0383 (ISSN) 1549-7887 (eISSN)

Vol. 26 4 377-390

Subject Categories

Civil Engineering

DOI

10.1080/15320383.2017.1319335

More information

Latest update

5/23/2019