Study of Solidification of Chromium-Containing Sludge by Heating with Silicates (3)

—Relation between Chromium-Leached and Addition of Active Carbon on Firing—

Abstract

The series of experiments have been conducted by the present authors to develop the solidification process for stabilization of sludges containing hazardous metals. In the previous works Cr₂O₃, which was took up as a model of sludge, was solidified by heating with the mixture of Na₂CO₃, CaCO₃and SiO₂and the leaching test was applied to determine the environmental adequacy of the ternary system Na₂O-CaO-SiO₂as chemical fixation agents. In the present study a small amount of active carbon was added on firing to examine the effect of reducing atmosphere on the concentration of chromium leached from the fired products.