Remediation Effects of Steel Slag and Fly Ash on Heavy Metal Contaminated Acidic Soil

Abstract

The remediation effects and mechanisms of the by-products of industry, fly ash and steel slag, on heavy metal contaminated acidic soil were investigated in this study. Fly ash was added at 0, 10, 20, 40, 60 and 80 g kg-1dry weight soil, and steel slag was added at 0, 1, 3, 5, 6 and 8 g kg-1dry weight soil, respectively. The results indicated that the application of fly ash and steel slag significantly increased soil pH values, and the increments improved with the increasing amendment dosages. The treatments of fly ash added at 20-40 g•kg-1and steel slag at 3-6 g•kg-1had the pH values within 5.5-7.0, and theSuperscript textneutral and weakly acidic soil environment was suitable for plant growth. The addition of amendments substantially decreased the avalibility of heavy metals, and the higher amendment dosages resulted in the lower CaCl2extractable heavy metal concentrations. X-ray diffraction analysis indicated that the mobile metals were mainly deposited as their silicates, phosphates and hydroxides in amended treatments. These results demonstrated that the application of fly ash and steel slag might be a potential strategy to remediate heavy metal contaminated acidic soil.