Heavy metals stabilization in lead zinc mine tailings by using mechanical, mechano-chemical, and microwave oven activation; tailing waste utilization in building materials

Abstract

Lead–zinc mine tailings are hazardous waste that is produced by mining activities. Poor tailings management can lead to heavy metals leaching into the groundwater or surrounding environment if not properly managed. In this study, lead zinc mine tailings were treated using several activation methods to stabilize their heavy metals. Thus, in this study, several activation methods like mechanical, mechano-chemical, and microwave oven activation were applied to stabilize the heavy metals and reuse them effectively in construction. Toxicity-characteristic leaching procedures were performed to analyze the leaching concentration based on USEPA standard limits. A modified sequential extraction procedure (BCR) was used to determine the detailed distribution of heavy metals. 20% of tailings were replaced with cement. Tailings aggregates used in construction reduce the cost of construction and minimize the emissions of CO₂ to the environment as cement consumption is reduced. Characterizations supported the stabilized structure of concrete after activation methods were applied. Overall, it was concluded that activation methods can treat tailings powders and make them suitable for safe utilization in construction. Mechanical activation (200 rpm), mechano-chemical-activation (Graphene Oxide, 0.03%), and microwave oven activation (high power) for 40 minutes was selected for successful applications for concrete based on tailings due to their better-stabilizing effects and cementous properties.