Study on Solidification of Chromium-Containing Sludge by Heating with Silicates (2)

—Effect of Firing Time and Addition of Al₂ O₃ on Chromium Extraction from Heated Mass—

Abstract

Previous work revealed that the optimum heating temperature for the solidification of Crcontained sludge by using the ternary system of Na₂O-CaO-SiO₂ as a chemical fixation agent was 800-1000°C. In this report, an optimum heating period to reduce the Cr-extraction was investigated between 30- 300 min at 1000°C. The leach test showed that the heating period of 30-120 min reduced the total Cr-extraction remarkably, and further extension of the period was not effective for reduction.