Utilization of sulphidic mine tailings in alkali-activated materials

Jenni Kiventerä,Mirja Illikainen,Jan Deja,Juho Yliniemi,Victor Ferreira,Lukasz Golek,J Castro-Gomes,S Yang,J Durán-Suárez,X Zhou,C Sangiorgi,M Górski

doi:10.1051/matecconf/201927401001

Abstract

Disposal of mine tailings is one of the most important environmental issues during the mining lifetime. Especially sulphidic tailings can cause environmental and ecological risks because of their tendency to oxidize in the presence of water or air. Because of small particle size and harmful chemical properties, utilization possibilities of sulphidic mine tailings are limited. The aim of the present study was to develop technologies to utilize sulphidic mine tailings in alkali activated materials. Alkali-activated materials also known as geopolymers are nanosized zeolite type or slightly amorphous materials comparable to traditional Portland cement concrete, which can physically encapsulate or chemically stabilize the hazardous elements such as heavy metals into the 3D structure. Mine tailing based geopolymer aggregates were successfully produced from sulphidic mine tailings with good physical properties. The geopolymer aggregates performed as a concrete aggregate comparable to commercial lightweight aggregates. In addition, geopolymer mortars were prepared from mine tailings. In mortar application, there is a need to add some co-binder such as blast furnace slag in order to achieve high strength for the material. The mine tailing based geopolymer structure has an ability to stabilize a large number of cationic species into the structure while some anionic species were not able to immobilize by alkaline activation.

Highlights

Disposal of mine tailings is one of the most important environmental issues during the lifetime of a mine
Even though the strength were higher the workability decreased with the higher concentration of alkaline solution
Gold mine tailings were able to be used as a raw material in alkali-activated materials with a proper co-binder material such as blast furnace slag or metakaolin

Summary

Introduction

Disposal of mine tailings is one of the most important environmental issues during the lifetime of a mine. In the EU, mining and quarrying are contributing 727 million tons waste, which is 28.3 % of the total waste amount [1] Some of these wastes, such as sulphidic mine tailings, consist of many harmful components which can cause several environmental and ecological risks because of their tendency to oxidize in the presence of water or air. These uneconomic residues are disposed into the impounding lakes with high water content. Alkali activation of hazardous waste materials can represent one of the environmentally friendly and low-cost treatment methods for the encapsulation of hazardous elements [3,4,5]. The geopolymer structure can have many excellent properties such as high strength, low density, micro- or nano-porosity, low shrinkage, high thermal stability, and high chemical and fire resistance [7]

Objectives

Results

Conclusion