Project: UTILIZATION OF SULPHIDE MINE TAILINGS IN GEOPOLYMER MATERIALS

Acronym	GEOSULF
Duration	01/03/2014 - 30/06/2017
Project Topic	The GEOSULF project aims to sustainable utilization of sulphide mine tailings in geopolymer materials. Three Universities from Finland, Poland and Portugal will develop geopolymerization recipes, geopolymer aggregates and concrete products utilizing sulphide mine tailings provided by Finnish and Polish gold and copper mines. In geopolymerization, alumina and silica rich materials are activated with alkali solution. The formed geopolymer is a three-dimensional amorphous network that can immobilize hazardous components into its structure. The project aims at deep understanding on geopolymerization of mine tailings into a form in which harmful substances cannot dissolve. The project involves four RTD parts: 1. Understanding of geopolymerization by model sulphide and heavy metal components; 2. Development of geopolymer recipes and aggregates from mine tailings; 3. Development of novel geopolymer based products like mine backfills and concrete bricks; 4. Environmental assessment of products developed. The project results in new treatment technologies, mining practices and novel products. Development of new methods and products will provide new business opportunities for companies and more jobs in EU and promote exportation business possibilities from EU to other countries. To roll out research results across all EU member states will promote generation of new European researcher network in the area of mine tailings utilization.
Project Results (after finalisation)	Disposal of mine tailings is one of the most important environmental issues during mine lifetime. In the EU, mining and quarrying are contributing 727 million tonswaste, which is 28.3 % of the total waste amount. 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. Alkali activation or geopolymerization is known to be an effective method to stabilize hazardous waste materials including the mine tailings. This aim of this project was to understand more deeply the methods how different elements can be stabilized and what are the possibilities to stabilize mine tailings with high amount of sulphates. The project involves the contributionof three different universities from Finland, Poland and Portugal in order to provide knowledge for more sustainable disposing methods for mine tailings all over the Europe. The Finnish mine tailings studied in this work had chemical composition promising for alkali-activation. However, the reactivity of the material was low, which means that there is need for co-binder to utilize these tailings in geopolymer materials. With a proper co-binder material such as blast furnace slag or metakaolin, it was possible to achieve strength required in construction materials. The Portuguese mine tailings had low aluminosilicate content, so it was proposed to use as an aggregate rather than a reactivecomponent. Even though there was a possibility to achieve good mechanical properties of geopolymer based on tailings and slag, the environmental analysis shows that there was increased leaching of oxyanions such as As and V after geopolymerization. Although the stabilization of anionicspecies was poor, it was possible to stabilize a large amount of different cationic species into the geopolymer structure. Longer curing period improved also the immobilization of oxyanion species. The immobilization mechanism should be further examined in order to understand the role of different parameters from stabilization point of view. It is possible to use mine tailings as geopolymer aggregates or fillers in concrete. The mine tailings were incorporated into mortar and concrete bricks either as partial aggregate replacement (sand) or in the form of lightweight aggregates previously prepared by geopolymerization of Finnish mine tailings. This introduction of mine tailings promoted obvious benefits in the fresh and hardened state of mortars and concretes. The introduction of mine tailing into a ceramic brick tile paste was also evaluated and it is a viable solution with improved final properties for this type of products. Nevertheless, the viability of this solution still requires further studies. The project shows promising results to use of sulphidic tailings as geopolymer aggregates in mortar or concrete. The project improved significantly the current understanding on geopolymerization of mine tailings. In future, tailings with different mineralogy (e.g. silicate tailings) might be further studied since the research related to geopolymerization of mine tailings is still at very initial stage.
Website	visit project website
Network	ERA-MIN
Call	Sustainable And Responsible Supply Of Primary Resources

Project partner

Number	Name	Role	Country
1	University of Oulu	Coordinator	Finland
2	University of Aveiro	Partner	Portugal
3	AGH University of Science and Technology	Partner	Poland