Projektdeltagare från Boliden, LTU och Swerim

A new product is developed from slag that reduces the concrete's climate impact!

18 October, 2023

In collaboration with Boliden, Swerim has developed equipment for water granulation of slag on a pilot scale. The experimental set-up has many possible future applications for handling various slag-based materials.

Slag in cement reduces the climate impact

The last step in slag handling at Rönnskär's copper smelter is the so-called granulation, where the treated slag from primary smelting is quickly cooled with the help of water. The resulting product, called iron sand, has several applications such as building materials and blasting sand.

Fine distribution and rapid cooling of slag

Granulering pågår hos Swerim
Granulation in progress. The slag is thrown with the help of water jets into a concrete compartment for later collection.

In a new initiative, Boliden is now working on developing a new product that reduces the use of calcium oxide (CaO) in cement, a pozzolan product (Supplementary Cementitious Material).

Swerim has carried out a series of trials in which a synthetic slag was produced on a pilot scale. The composition of the synthetic slag is optimized to maximize reactivity in cement applications and results in a cement product (SCM). The product is developed by Boliden in collaboration with Luleå University of Technology (Fredrik Engström, Andreas Lennartsson och Anton Andersson) and RISE Research Institutes of Sweden (Katarina Malaga och Sumit Srivastava). With the help of new pilot equipment, water granulation of the new product on a tonne scale could be carried out at the desired cooling rate. The test setup can be used in future projects to optimize or evaluate water granulation of various slag-based materials.

­– The collaboration with Swerim is of great importance to be able to go from laboratory tests to pilot scale and reduce the risk in investments in industrial production capacity, says Åke Roos, program manager, business development Boliden Smelters.

First image: Project participants from Boliden, LTU and Swerim review the produced material.