Transforming mining residues to valuable products Stage II

Purpose and goal:

The Residue2Product-II project is dedicated to supporting the Swedish Mining Innovation Roadmap 2022´s objectives for the mining, metallurgy and recycling themes. Our project´s primary goals include decreasing the loss of valuable minerals and metals, enhancing the recovery of by-products, reducing the environmental impact of mining residues, and developing a resource-efficient and eco-friendly waste-to-product recovery approach.

Specifically, our focus is on transforming waste gypsum and pyrite tailings into valuable commodities like CaO, SO2, and Fe. Expected results and effects:

The findings of this full-scale project will significantly benefit the Swedish mining and metallurgical industry by offering better residue management practices. Moreover, these results can be applied to the extraction of base metals from sulphidic ores beyond the Swedish mining industry. Through this proposed project, we aim to promote the sustainability of the mining industry, minimize environmental impacts from waste generation, reduce CO2 emissions from conventional recycling methods of gypsum, and generate economic value by converting residues into useful products.

Approach and implementation:

The planned work is divided into six interconnected work packages; WP1) Project coordination by LTU; WP2) Sampling and Theoretical exploration which will be handled by LTU and Boliden; WP3) Pyrite decomposition which will be conducted by LTU; and WP4) Pyrrhotite reduction and CaS formation which will be handled by LTU (process metallurgy and mineral processing groups); WP5) Gypsum conversion which will be handled mainly by LTU and Cementa; and WP6) Product and process evaluation which will be handled mainly by Boliden and Cementa.