Evaluation the Solidification/Stabilization of Heavy Metals by Portland Cement

摘要

Many of the solutions used in the site to treat pollution, including remediation of heavy metals and hazardous wastes by solidification/stabilization (S/S) with cement as a binder. S/S is one of the most commonly methods used for treating inorganic wastes. The aims of this research, evaluation the cement Solidification / stabilization (S/S) through study the leaching characteristics of four different synthetic heavy metal wastes (Chromium, Iron, Zinc, and Manganese ions). Finally determine the strength of Cement based (S/S) by Unconfined Compressive Strength (UCS) testing. In this study used three loads of pollution in three mix designs by contaminated sands. The result of the unconfined compression test, it was observed value 1-15 MPa with OPC cement content 25% in the solidification / stabilization process was a good enough to comply with the limited value set by the (US EPA). In addition, the concentration of zinc ion was 500-1500- 3000 kg / mg caused an increase in compressive strength in the early period of age, But degrease at a later age. Increase in Iron concentration ion caused an increase in compressive strength at a later age, the Effective retention percentages show to be (97, 93.5, 96 and 92) for iron, zinc, manganese and chromium ions respectively, which obtain with initial contaminated exceeded 3000 mg / kg. Also found the high effectiveness in holding and retaining metals within the matrix of solidification / stabilization at the particle size above 9.5 mm, Also showed the samples (Mn and Cr) with the low amount of cement in the mix treatment was not able to retain the required TCLP regulatory limits value, the initial extraction pH 4.9 . However, the final pH 9.5 is alkaline and stabilization effects of the cement matrix.