Solidification/Stabilization of hazardous wastes from the mine "La Prieta" in Hidalgo del Parral, Chihuahua, México

Abstract

The mining industry of Mexico is one of the oldest and most useful activity for the Mexican economy, however it has a high environment impact from the subsoil to the atmosphere. It generates a large amount of solid, liquid and gaseous wastes. The most impacted mining wastes are tailings due to the high content of toxic components. One of the most widespread alternatives for handling toxic metal is the blocking in a manageable solid system which allows the proper solidification/stabilization (S/S) of hazardous components and its subsequent safe disposal. Ordinary Portland Cement (OPC) has been widely studied to retain potentially toxic heavy metals, but the use of other alternative binders is receiving growing attention. For instance, the use of Calcium Aluminate Cement (CAC) to safely encapsulate hazardous materials has proved to be highly effective. In this study both binding matrices, OPC and CAC, were assayed to encapsulate loaded naturally toxic metal mining tailings with the aim to obtain a waste-containing solid block with improved management and successfully disposal. A semi-dynamic Tank Test (EA NEN 7375, 2004) was applied in elucidating leaching mechanisms and to evaluate the supporting evidence in solidify/stabilize of these hazardous wastes in this type of cement-based matrices.