Chemical Leaching of Antimony and Other Metals from Small Arms Shooting Range Soil

Abstract

Military small arms shooting range (SASR) soils are heavily polluted by metals like copper, lead, antimony, and zinc. This study was carried out to define efficient operating conditions to solubilize these metals by a chemical leaching technique. The comparison of different leaching reagents (HCl, H2SO4, CH3COOH, and EDTA) has revealed that sulfuric acid leaching coupled with the addition of sodium chloride is the most interesting option for the solubilization of Cu, Pb, Sb, and Zn from the finest fractions (<125 μm) of SASR soil. The initial metal contents of the soil sample were 1,760 mg Cu kg−1, 43,300 mg Pb kg−1, 780 mg Sb kg−1, and 355 mg Zn kg−1. The important operational parameters for leaching ([H2SO4], [NaCl], pulp density, reaction time, and temperature) were also studied. The optimum leaching conditions identified were 1 M H2SO4 and 4 M NaCl with a 10 % (w/v) soil pulp density at ambient temperature. In these conditions, 83, 75, 61, and 72 % of Cu, Pb, Sb, and Zn were respectively solubilized after only 1 h of treatment. The use of five successive leaching steps and two washing steps removed 96, 99, 84 and 86 % of Cu, Pb, Sb, and Zn respectively from the soil.