# Stabilization of Ultrafine Iron Tailings with Acrylic–Styrene Copolymer for Sustainable Geotechnical Applications

## TL;DR

This study shows how adding an acrylic-styrene copolymer can strengthen ultrafine iron ore tailings, making them usable in construction.

## Contribution

The novel use of an acrylic–styrene copolymer to stabilize ultrafine iron tailings for geotechnical applications is introduced.

## Key findings

- Polymer addition increased unconfined compressive strength from 49 kPa to over 3000 kPa.
- Permeability remained low at 10−6 cm/s, indicating the polymer acts as a binder.
- A power-law model successfully predicted strength based on polymer content and density.

## Abstract

Considerable research in recent years has examined the reuse of tailings; however, the lack of particle cohesion limits their application as construction materials. Therefore, this study assessed the stabilization of ultrafine iron ore tailings using an acrylic–styrene copolymer. Geotechnical characterization and polymer dosage, hydromechanical and microstructural tests were carried out, including unconfined compressive strength (UCS), permeability, scanning electron microscopy (SEM) and microtomography (μCT). The polymer effectively enhanced the mechanical behavior of the tailings, increasing the UCS from 49 kPa for untreated material to 2114 kPa and 3324 kPa for 30% and 40% polymer content, respectively. A robust power-law model (R2 ≥ 0.90), based on the porosity/volumetric polymer index (η/Pᵢᵥ), was developed to predict strength, showing that mechanical gains can be achieved by increasing either polymer content or dry density, as supported by statistical analyses. Permeability remained on the order of 10−6 cm/s regardless of polymer addition, indicating that the polymer does not fill voids but instead acts as a binding agent, as confirmed by SEM and μCT analyses. Overall, this study establishes a technically feasible and sustainable approach for tailings management, highlighting the potential of polymer stabilization to turn environmentally challenging tailings into functional geotechnical materials.