Copper smelter slag as bed material in fluidized bed combustion

This project examines the possibility to use granulated copper-smelter slag, järnsand in Swedish, as bed material in fluidized-bed combustion.

Järnsand is a low-value byproduct produced in huge quantities by the company Boliden. It consists mainly of iron and silicon oxides. During combustion, järnsand acts as a so-called oxygen carrier, meaning that it is capable of absorbing and releasing oxygen and acting as an oxygen buffer. Oxygen carriers have been shown to significantly improve the performance of existing boilers and their use in combustion is currently being commercialized by the company Improbed.

The ultimate goal of the project is to allow for the replacement of silica sand in combustion applications with the affordable secondary byproduct järnsand. This would lead to reduced outtake of primary minerals, and potentially to reduced costs and improved performance for existing boilers.


Magnus Rydén

Chalmers University of Technology

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Project information


Boliden Commercial AB
Improbed AB

Time schedule

November 2022 - June 2024

Total cost of project

1 540 250 SEK

Swedish Energy Agency project number