Work

Sustainable conversion of acid mine drainage sludge into high-quality iron-based pigments through thermal processing

Year: 2025

Type: article

Abstract: This study investigates the calcination of Acid Mine Drainage (AMD) sludge to produce stable iron-based pigments, providing a sustainable solution for mining waste management. Thermal processing at temperatures ranging from 100 °C to 1200 °C led to critical mineralogical transformations: dehydration of gypsum to anhydrite at 400 °C, conversion of schwertmannite to hematite at 800 °C, and formation of magnetite at 1200 °C, as confirmed by XRD and TG-DSC analyses. These transformations enhanced pigment stability and optical properties, with ΔE* ab values demonstrating colour stability comparable to commercial standards. Pigments exhibited vibrant red hues at 800 °C and transitioned to dark-grey tones at 1200 °C, aligning with industrial requirements. A key innovation of this study is the introduction of a predictive polynomial model for ΔE * ab variation that was developed to optimize pigment production processes. This work highlights the potential of AMD sludge valorisation to promote circular economy principles, reducing environmental risks and creating high-value materials for industrial applications.

Source: Process Safety and Environmental Protection

DOI: 10.1016/j.psep.2025.107181

Authors: Alexandra Zamfir, Aurelia Meghea, Ovidiu Cristian Oprea, Maria Mihaly

Institution: Universitatea Națională de Știință și Tehnologie Politehnica București

Language: English

Topic: Mine drainage and remediation techniques

Subfield: Environmental Chemistry

Field: Environmental Science

Domain: Physical Sciences

SDG: Responsible consumption and production

Open Access status: hybrid

Estimated APC paid: $3,500