Alkali-activation of industrial aluminosilicate sidestreams: Application for mine water treatment and sediment remediation

Thesis event information

Date and time of the thesis defence

Place of the thesis defence

University of Oulu, L6

Topic of the dissertation

Alkali-activation of industrial aluminosilicate sidestreams: Application for mine water treatment and sediment remediation

Doctoral candidate

Master of Science Johanna Laukkanen

Faculty and unit

University of Oulu Graduate School, Faculty of Technology, Sustainable Chemistry / Kerttu Saalasti Institute

Subject of study

Sustainable Chemistry


Professor Tuula Tuhkanen, University of Jyväskylä


Professor Ulla Lassi, University of Oulu

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Industrial sidestreams can be used to minimize the environmental impact of mining

Industrial sidestreams can be used to produce water treatment materials that can be used both to clean leachate from mines and to bind metals in sediments in lakes near mines. However, the durability of the material and the effects of water chemistry on the behaviour of the manufactured materials need to be further investigated.

The industry generates large quantities of both solid sidestreams and water requiring treatment. The need for new uses for the by-products generated has grown strongly in recent years. At the same time, environmental issues have received more attention and the need to clean up already contaminated sites has been recognized.

The challenge for industrial wastewater, and in particular for mine water, is the diversity of the resulting waters from a hydrochemical point of view. Consequently, the treatment methods developed may not be effective between different mines. The challenge is to find suitable side stream materials for different applications.

The aim of this dissertation was to examine a number of different industrial side-stream materials, to prepare water-treatment materials from them and to investigate their performance in treating mine leachate and stabilizing lake sediments. The performance of materials in these applications was investigated in both laboratory and field tests. The leachate treatment experiment was carried out at the closed nickel mine in Hitura and the sediment stabilization experiments were carried out in Lake Kivijärvi in Sotkamo.

An important new aspect is the evaluation of the influence of the curing time of the prepared material on the adsorption properties of the material. As a result of the study, it can be concluded that the blast furnace slag-based water treatment material removes especially nickel from mine leachate and may be well suited as a material for passive water treatment structures in the future. The sediment stabilization trials were also promising and may allow for a much more environmentally friendly alternative to lake dredging in the future.

The study has been useful in exploring new uses for industrial sidestreams. In particular, the testing of manufactured materials both on a laboratory and on a pilot scale will provide a broader understanding of the performance and potential of the materials on an industrial scale.
Last updated: 23.1.2024